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Po a Pe
CHEMISTRY:
GENERAL, MEDICAL, AND PHARMACEUTICAL.
At the First International Pharmaceutical Exhibi-
fton, held in Vienna in August, 1883, for this
Manual the Author was awarded a Gola Medal.
At the Second, held in Prague in 1896, he
received for the book the still higher, indeed
the highest, prize of a Diploma of Honor.
The Nineteenth Edition of thia Manual has been
revived from the Eighteenth English Edition
and is adapted to conform to the new United
States Pharmacopwia.
CHEMISTRY:
GENERAL, MEDICAL, AND PHARMACEUTICAL,
INCLU DING
THE CHEMISTRY OF THE U. 8. PHARMACOPQIA.
A MANUAL
ON THE SCIENCE OF CHEMISTRY, AND ITS APPLICA-
TIONS IN MEDICINE AND PHARMACY.
BY
JOHN ATTFIELD, F.R.S.,
M. A. AND PH. D. (T(UBINGEN), F. 1. C., F.C. &
PROFESSOR OF PRACTICAL CHEMISTRY TO THE PHARMACEUTICAL SOCIETY OF GREAT
BRITAIN, 1862-96; FORMERLY DEMONSTRATOR OF CHEMISTRY AT ST BARTHOLOMEW’S
HOSPITAL, LONDON; HONORARY MEMBER OF TWENTY-THREE SOCIETIES,
ASSOCIATIONS, AND COLLEGES OF PHARMACY IN EUROPE AND AMERICA;
ONE OF THE THREF. EDITORS OF THE BRITISH PHARMACOPCEIA, 1885;
EDITOR OF THE ADDENDUM TO THE BRITISH PHARMACOPGIA,
EDITOR OF THE BRITISH PHARMACOPGEIA, 1898, AND
OF IT8 INDIAN AND COLONIAL ADDENDUM, 1900
Epitep sy LEONARD DOBBIN
PH. D. (WURZBURG), F. I. C., F.C. 8.
LECTURER ON CHEMISTRY IN THE UNIVERSITY OF EDINBURGH: LATELY
EXAMINER IN CHEMISTRY ON THE BOARD OF EXAMINERS FOR SCOTLAND,
OF THE PHARMACEUTICAL SOCIETY OF GREAT BRITAIN
NINETEENTH EDITION
LEA BROTHERS & CO.,
PHILADELPHIA AND NEW YORK,
GA!
he
— ee | ee
LEA BROTHERS & CO.
Authority to use for comment the Pharmacopoeia of the United
States of America (Eighth Decennial Revision), in this volume, has
been granted by the Board of Trustees of the United States Pharmaco-
poial Convention; which Board of Trustees is in no way responsible
for the accuracy of any translations of the Official Weights and
Measures, or for any statement as to strength of Official Preparations.
DORNAN, PRINTER,
PHILADELPHIA.
arn
ARE
\ar&
“But the greatest error of all is, mistaking the ultimate
end of knowledge; for some men covet knowledge out of a
natural curiosity and inguisitive temper; some to entertain
the mind with variety and delight ; some for ornament and
reputation ; some for victory and contention ; many for lucre
and a livelihood; and but few for employing the divine
gift of reason to the use and benefit of mankind.”—Lorp
Bacon.
“T hold that the greatest friend to man is labor; that
knowledge without toil, if possible, were worthless; that
toil in pursuit of knowledge is the best knowledge we can
attain; that the continuous effort for fame is nobler than
fame itself; that it is not wealth suddenly acquired which
is deserving of homage, but the virtues which a man exer-
cises In the slow pursuit of wealth—the abilities so called
forth, the self-denials so imposed; in a word, that Labor
and Patience are the true schoolmasters on earth.""—LorD
LYTTON.
“T want to hearn all that one human being can. It is
awful to be buried alive in the coffin of one’s own ignorance
and helplessness.”"—GRAHAM TRAVERS.
PREFACE.
Tue short title on the back of a book, and even the words on
the title-page, are generally, and even necessarily, imperfect
descriptions of the contents, and hence not unfrequently induce
at the outset misconceptions in the minds of readers, The
author of Chemistry: General, Medical, and Pharmaceutical,
would at once state, therefore, that his chief aim is to teach
the science of chemistry to medical and pharmaceutical
pupils. So far as laws and principles are concerned, the book
is a work on General Chemistry ; but inasmuch as those laws
and principles are elucidated and illustrated by that large por-
tion of chemistry which is directly interesting to medical prac-
titioners and pharmacists, the book may be said to be a work
on Medical Chemistry and on Pharmaceutical Chemistry. Only
in this conventional sense would the author speak of Medical
and Pharmaceutical Chemistry; for the truths of chemistry
are the same for all students—crystalline verities which cannot
be expanded or compressed to suit any class of workers. The
leading priacipies of the science, however, can as easily be
illustrated by or deduced from those facts which have interest
as from those which have little or no special interest for the
followers of medicine and pharmacy. The grand and simple
leading truths or laws of chemistry, the lesser truths or prin-
ciples, and nearly all the interesting relationships of elements
and compounds—in a word, the science of chemistry—can be
taught to medical and pharmaceutical students with little other
aid than that afforded by the materials which lie in rich abun-
dance all around these workers. Such a mode of teaching | the
7% meral principles of the science and their applications in medi-
ein sand pharmacy is adopted in this volume. It isa mode which
gree ily increases the usefulness of the science tu the students
Wii
Vii PREFACE.
chiefly addressed, while it in no way diminishes the value of
chemistry to them as an instrument of mental culture—an
instrument which sharpens and expands the powers of observa-
tion, which enlarges and strengthens memory and imagina-
tion, which gives point to the perceptive faculties, and which
develops and elaborates the powers of thought and of reason.
This Manual is intended, then, as a systematic exponent of
the science of chemistry, but is written mainly for the pupils,
assistants, and principals engaged in medicine and pharmacy.
It is a Manual of Applied Chemistry or Technical Chemistry,
but it is first of all a Manual of Chemistry.
The book will be found equally useful as a reading-book for
students having no opportunities of attending lectures or per-
forming experiments, or, on the other hand, as a text-book for
college pupils; while its comprehensive Index, containing
nearly ten thousand references, will fit the work for after-
consultation in the course of business or professional practice.
From most other chemical text-books it differs in three par-
ticulars : first, in the exclusion of matter relating to compounds
which at present are only of interest to the scientific chemist ;
whose aims have no special relation to medicine and pharmacy ;
secondly, in containing more or less of the chemistry of every
substance recognized officially or in general practice as a
remedial agent; thirdly, in the paragraphs being so cast that
the volume may be used as a guide in studying the science
experimentally,
The order of subjects is that which, in the author's opinion,
best meets the requirements of medical and pharmaceutical
students in Great. Britain, Ireland, India, the British colonies,
and the United States of America. Introductory pages are
devoted to a few leading properties of the elements. <A
review of the facts thus unfolded affords opportunity for stat-
ing the views of philosophers respecting the manner in which
these elements influence each other as components of terres-
trial matter. The consideration in detail of the relations of
the elementary and compound radicals follows, synthetical and
analytical bearings being pointed out, and attention frequently
PREFACE. ix
directed to connecting or underlying truths or general prin-
ciples. The chemistry of substances met with in vegetables
and animals, or of similar substances artificially produced (the
so-called “organic chemistry”), is next considered. Chemical
toxicology and the chemical as well as microscopical characters
of morbid urine, urinary sediments, and calculi are then given.
The coneluding sections form a laboratory-guide to beginners
in the study of quantitative analysis.
In the course of the treatment outlined in the preceding
paragraph it will be observed that the whole of the elements
are first noticed very shortly, to give the pupil a general view
of his course of study, and afterward at length and _thor-
oughly; that the chemistry of the metallic radicals precedes
that of the acid radicals (a term applied consistently through-
out the Mannal to designate that part of each of the acids
which is not replaceable hydrogen); and that while the
metallic radicals are arranged according to their analytical
relations, the common radicals are arranged according to
exchangeable value or quantivalence, and the rarer acid
radicals alphabetically. By this plan the more important
facts and principles are repeatedly brought under consideration,
the pointa of view, however, differing according as interest is
concentrated on physical, synthetical, analytical, or quantitative
. This arrangement of matter was adopted, also, partly
in the belief that the separate and general truths of chemistry
never do or can enter the mind in the order of any scientific classi-
fication at present possible. Chemical facts are not yet united
by any single, consistent theory. In the current state of
chemical knowledge consistency in the methodical arrangement
even of clements can only be carried out in one direction, and
is Hecessarily accompanied by inconsistencies in other directions
—a result most perplexing to learners, and hence totally sub-
yersive of the chief advantages of classification. For this reason
the writer has preferred to lead wp to, rather than follow, scien-
he classification—has allowed analogies and affinities to
Biggest, rather than be suggested by, classification, Among the
acidulous radicals, especially, any known system of classification
x PREFACE,
would have given undue prominence to one set of relations,
and undeserved obscurity to others. Then, by separating
more important from less important matter, instruction is
adapted to the wants of gentlemen whose opportunities of
studying chemistry vary greatly, and are unavoidably insuf-
ficient to enable them to gain a knowledge of the whole area
of the science. One great advantage of the mode of treat-
ment is, that difficulties of nomenclature, notation, chemical
constitution, and even those arising from conventionality of
language, are explained as they arise, instead of being massed
under the head of “Introductory Chapters,’ “ Preliminary
Considerations,” or “ General Remarks,” which are not unfre-
quently too difficult to be understood by a beginner, too vo-
luminous to be remembered except by the aid of subsequent
lessons, and are consequently the cause of much trouble and
confusion. ‘This plan has also admitted of greater prom-
inence being given to “The General Principles of Chemical
Philosophy,” the only section to which the student is asked
frequently to return until he finds himself naturally employing
those principles in the interpretation of the phenomena obtained
by experiment,
The metric system of weights and measures (that which,
doubtless, is destined to supersede all others) is alone used
in the sections on quantitative analysis. In other parts of
the Manual avoirdupois weights and imperial measures are
employed, necessarily.
It is hoped that the numerous etymological references scat-
tered throughout the following pages will be found useful.
Words in Greek continue to be rendered, by special request,
in English characters, letter for letter. The word © official”
is used throughout for things recognized officially by the com-
pilers of pharmacopeias.
Chemical substances recognized in the United States Phar-
macopeia, but not in the British Pharmacopwia, have, never-
theless, a certain amount of notice in the British editions of
the Manual, and the chemical substances official in Great
Britain are noticed in the American editions.
PREFACE. x1
Students are strongly recommended to test their progress by
frequent examination. To this end appropriate questions are
appended to each subject.
The author's ideal of a manual of chemistry for medical and
pharmaceutical students is, then, one in which not only the
sctence of chemistry is taught, but in which the chemistry
of every substance having interest for the followers of med-
icine and pharmacy is noticed at more or less length in pro-
portion to its importance, and at least its position in relation
to the leading principles of chemistry is set forth with all
attainable exactness. The extent to which he has realized
this ideal he leaves to others to decide. Such a work will
doubtless in certain parts partake of the character of a diction-
ary; but this is by no means a fault, especially if a good index
be appended, for the points of contact. between pure and applied
chemistry are thus multiplied, and abundant outlets supplied by
which a lover of the science may pass into other chemical domains
by aid of other guides, or even into the regions of original re-
search. Among the rarer alkaloids, bitter bodies, glucosides, salts
of organic radicals, solid fats, fixed oils, volatile oils, resins, oleo-
resins, gum-resins, balsams, and coloring-matters mentioned in
this volume, will be found many such points whence the ardent
student may start for the well-known, the less-known, or the
untrodden paths of scientific chemistry.
WATForD, HERTS, ENGLAND,
September, 1906.
No. oF
EDITION.
]
2
~I
10
11
12
18
14
15
16
17
18
LIST OF PREVIOUS EDITIONS.
DATE,
1867
1869
1870
1872
1873
1875
1876
1879
1881
18838
1885
1889
1889
1893
1893
1898
1808
1903 |
xii
NOTES.
A hand-book of practical chemistry only.
This and succeeding editions included the
chemistry of the British Pharmacoporia.
American edition : adapted to the United
States Pharmacopeia.
English edition.
American edition,
English edition. This and succeeding editions
contained notices of substances included in
the Indian Pharmacopeia.
American edition.
English editions.
American edition.
English edition.
American edition.
English edition.
American edition,
English edition.
American edition.
English editions.
ADVICE TO STUDENTS
RESPECTING THEIR OBJECT IN STUDYING.
Avorp studying chemistry, or indeed any subject, merely by
way of “preparation for examination ;” all ordinary “ exam-
inations” being, admittedly, inefficient tests of competency.
Do not so mistake the means for the end. You are studying
to fit yourself for your position in the world. Work dili-
gently, study thoughtfully and deliberately; above all, be
thorough, otherwise your knowledge will be inaccurate and
transient, and will be unaccompanied by that enlightenment
of the understanding, that mental training, mental discipline,
and general elevation of the intellect, which constitute, in a
word, education. When you are thus educated you will with
ease and pleasure pass any examination in the knowledge you
have thus acquired.
All authorities on education, whether statesmen, teachers,
or examiners, regard “ examinations,” even by the most highly
skilled “ Board,” with ample time at its disposal and a wide
area from which to select questions, as but a partial test of
knowledge and an imperfect test of education. It is the least
unsatisfactory, however, that has been devised, and is especially
useful when, following instead of leading education, it is re-
stricted to the subjects of a well-defined, earnestly followed,
compulsory public curriculum of study—a curriculum directed
by a competent representative body, administered by properly
qualified teachers, and followed by pupils who have had sound
preliminary training.
Students! in all honor and in the highest self-interest take
care that any inefficiencies inseparable from * examination ” are
abundantly compensated by the extent and precision of your
knowledge and by the soundness and thoroughness of your
whole education.
xiii
APPARATUS.
List or Apraratus for ExrertmMents in ANALYSIS.
List of apparatus suitable for the three months’ course of practi-
cal chemistry in the summer session of medical schools or for any
similar series of lessons—ineluding the preparation of elementary
wases, analytical reactions of common metals and acidulous radicals,
analysis of single salts, chemical toxicology, and the examination
of urine, urinary sediments, and caleuli:
One dozen test-tubes, A 2-inch and a 35-inch evaporat-
Test-tube stand. ing-basin,
Test-tube cleaning-brush, , Two porcelain crucibles.
A few pieces of glass tubing, | Blowpipe.
eight to sixteen inches long, | Crucible tongs.
with a few inches of india-rub- | Round file. —
ber tubing to fit. Triangular file.
Small flask, Small retort-stand.
Two small beakers. Sand-tray.
Two small funnels. Wire triangles.
Two watch-glasses, Platinum wire and foil.
Two or three glass rods. | Test-papers.
Wash-bottle. Filter-paper.
Small pestle and mortar. Towel.
A 2-pint earthenware basin. Two dozen corks,
(This set, packed in a case, can be obtained of any chemical-appara-
ius maker for about seven dollars. )
List or Apparatus ror Exreriments 1n SyNTHESIS AND ANALYSIS.
A larger set, suitable for the performance of most of the synthet-
ical as well as qualitative analytical experiments described in this
Manual :
A set of evaporating-basins, of the | Two soup-plates.
following sizes ; One flat-plate.
One 3-inch; one 4-inch: one 64-| Two spatula knives,
inch; one 7}-ineh; one 84-inch. | One pair of scissors.
One retort-stand and three rings. | One round file.
Two test-glasses. One triangular file.
One half&pint flask. Half a pound of glass rod.
Half a quire of filter-paper, Half a pound of glass tubing.
Two porcelain pas § Wi One foot of small india-rubber
One measure-class, 5 oz, tubing.
Blowpipe, 8-inch. Three dozen corks of various
Two glass funnels. sixes,
One dozen test-tubes (hard glass). | Platinum wire and foil.
(ine test-tube brush. | Test-papers.
One pair of 8-inch brass eracible A nest of three beakers.
tongs. One test-tube stand.
(This set, packed in a case, can be obtained of any chemical-appara-
lus maker for ahout twelve dollars.)
A sponge, towels, and a note-book may be included,
MIV
APPARATUS.
List of Furnitvre or A CoemicaL LAsorarory.
The following glam should be ready to hand for students fol-
lowing an ex
apart for the purpose:
= bench Saihcas pea stool.
ater-supply and waste-pipe.
A Suphoad attached toa aTmiey
with an outward draught.
A furnace fed with coke ; tongs,
hot-plate or sand-bath, ete.
A wnaate-box.
Shelves for chemical and other
materials ad yes or bottles,
Gas-supply and lamp with flexible
tube (or @ spirit-lamp and
spirit).
Other articles, such as flasks, retorts, receivers, condensers, large
evaporating-dishes, may be obtained as wanted
Analysis Dp apparatus described in the sections
be req
ed course of practical chemistry, in a room set
Test-tube rack, two dozen holes,
Tron stand or cylinder for support-
ing large dishes,
Iron adapters for fitting dishes to
cylinder.
Pestle and mortar, 5 or 6 inches.
One 6-inch funnel.
Brown pan, |- or 2-gallon.
White jug, I-gallon.
Water-bottle, quart.
Twenty-eight test-bottles, 6-oz,
In Quantitative
on that subject will
List or From Reacents.
Certain chemical substances are used so frequently in analytical
tles in front of the operator.
that it is desirable to have small quantities placed in bot-
| (See p. 22.
As these reagents are
generally = ge in a stute of solution, nearly all the solid salts
at once
may
should be well s
issolved (in distilled water), The bottles employed
pered, and of 5 or 6 ounces capacity. Common
glass bottles of this size may be had for about one dollar and a
per dozen. The bottles should not be more than about
with ease and precision.
full ; single drops, if required, can then be poured out
is e following list of test-solutions 1s
recommended ; directions for methods of preparing the substances
not readily purchasable will be found by referring to the Index:
Sulphuric Acid, Cone. and dilute. | r
itric oh * | Sodium, 5 to 15 percent.
be
Potassium Hydroxide, 5 percent,
ota
Hydroxide Ammonia, 10 percent.
Lime-water, saturated.
‘The next nine may contain about 10 percent, of solid salt :
Ammonium Carbonate, with «
ittle solution of Ammonia
Ammonium Chloride.
Ammonium Hydrosulphide.
Barium Chloride.
Caleiu rit Chloride.
Potassium Chromate.
Sodium Bitartrate,
Xvi SOLID CHEMICAL SUBSTANCES
The succeeding seven may have a strength of about 5 percent. :
Potassium Ferrocyanide. | Ferric Chloride.
Potassium Ferricyanide. Silver Nitrate.
Potassium Iodide. Chloroplatinic Acid.
Ammonium Oxalate.
a ee -_——- --—-
Lists OF SOLID CHEMICAL SUBSTANCES FOR StTupy.
List of chemical substances necessary for the practical study of the
non-metallic elements mentioned un pp. 17 to 37. The quantities are
sufficient. for several experiments :
Potassium Chlorate . . . 1oz. Phosphorus ... . . . $02.
Black Manganese Oxide . 1 oz. | Hydrochloric Acid . . . J 2.
Zine . 2... ew ee . Loz! Sulphur... .... * doz.
Sulphuric Acid . . . . . 2oz. | ludine. ..... ... doz
List of chemical substances necessary for the analytical study of
the important inctallic and acidulous radicals (pp. 71 to 361). The
(quantities will depend on the frequency with ‘which experiments are
repeated or analyses performed ; those mentioned are sufficient for
one or two students. The eight substances mentioned in the above
list are included : |
The set of test-solutions described | Black Manganese Oxide . 3 Ib.
in the previous section : ' Manganese Chloride. . . 4 oz.
Potassium Carbonate . . 1 oz. Cobalt Chloride. . . . 50 grs.
Tartaric Acid . . .. . Loz. | Nickel Nitrate... . . 402.
Litmus ........ 4}oz. | Chromic Chloride... 1 oz.
Magnesium Sulphate . . 1 oz. | Gold-leaves. . 2... 2or3.
Zine Sulphate... . . 1oz.| Cadmium Chloride . . } oz.
Alum... ..... 102. j Bismuth Nitrate... . } oz.
Ferrous Sulphide. . . 1 Ib. | Potassium Bromide .. } oz.
Oak-galls .... Los Starch 2... . le. (los.
Potassium Thiveyanate . | 02. Potassium Nitrate . . . 1 oz.
Arsenic Trioxide =. ©. 3.02. Copper borings or turnings 1 oz.
Zine 2... ..... 4 Ib. Indigo rrr i 2
Chareval Loe 3 db. | Potassium Chlorate. . . 1 os.
Ferrous Sulphate - low. |Todine . 2... 2... Jon.
Copper-foll 2. 2 6. © Loz. Alcohol (90 to 95 percent.) 1 oz.
Copper Sulphate loz. Sulphur... .. . . Los.
Tartarated Antimony oz. Potassium Acid Oxalate . 1 oz.
Mercury 2... 2... Loz) Citrie Acid 2. 2... . Loz.
Mercurie Chloride. =. 4oz. Phosphorus . . 2... 1 oz.
Cslomel 2... 2... doz. Borax. 2...) los.
Tin. 2. 2... Doz. Turmerie 2... 2... Jon.
Potassium Bicarbonate. 1oz. Benzoie Acid. 2... 50 grs.
Lead Acetate 2.0. 0... Loz. Fluor Spar... . . 1 oz.
Potassium Cyanide. . 2) 4.02. Tannie Acid 2... 50 ers.
Sodium Thiosulphate . 2 loz. Callie Acid 2...) . 50 gre.
A Lithium Salt... . 0 1Ogrs. Pyrogallic Acid ©. . 50 grs.
Strontium Nitrate . . . | 02.
CHEMICALS. Xvi
The quantities of materials required for the study of chemistry
synthetically will necessarily vary with the desires and tastes of the
operator or according to the number and requirements of students
working together,
The materials that will be needed for the home-study of organic
chemistry will vary with the requirements of the student. By the
time he has qualified himself for a preliminary experimental course
in that section of the science he may trust largely to his own judg-
ment as regards both materials and apparatus.
CONTRACTIONS USED IN THIS MANUAL.
B. P., British Pharmacopeeia. F., Fahrenheit.
U.S. P., United States Pharma- | grm., Gramme.
cuporia. mm., Millimetre.
C., Centigrade. T.S., Test solution, U.S. P.
Ce., Cubic centimetres. V.S., Volumetric solution, U.S. P.
CONTENTS.
PREFACE... .. we ew ew ee we ht ht el
ADVICE 10 STUDENTS we ee ee we ee
Lists OF APPARATUS ... .
LIsT OF FURNITURE OF A CHEMICAL “LABORATORY
LIST OF FLUID REAGENTS . .
LISTS OF SOLID CHEMICAL SUBSTANCE ES FOR stu DY
INTRODUCTION
(7ENERAL PROPERTIES OF THE Nox-M ETALLIC ELEMENTS,
DERIVATION OF NAMES OF ELEMENTS
NUMERICAL AND PHYSICAL MATTERS
THE GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY .
THE METALLIC ELEMENTS, THEIR OFFICIAL PREPARA-
TIONS AND TESTS: ;
Salts of Potassium, Sodium, Ammonium, Lithium,
Barium, Strontium, Calcium, Magnesium, Zinc,
Manganese, Cobalt, Nickel, Aluminium, Iron,
Chromium, Arsenic, Antimony, Tin, Gold, Platinum,
Copper, Mercury, Lead, Bismuth, Cadmium, Silver .
. 243
ANALYTICAL TABLES FOR THE METALS
Common Actp RADICALS, OFFICIAL ACIDS, AND TESTS:
Chlorides, Bromides, Iodides, Cyanides, Nitrates, Hypo-
chlorites, Chlorates, Bromates, Todatex, Acetates,
Sulphides, Sulphites, Sulphates, Thiosulphates, Persul-
phates, Carbonates, Oxalates, Turtrates, Citrates, Phos-
phates, Borates,
SALTS OF RARER ACID RADICALS:
Benzoates, Cyanates, Formates, Hippurates, Ferrocy-
anides, Ferricyanides, Fluorides, © Hypophosphites,
Lactates, Malates, Meconates, Metaphosphates, Ni-
trites, Phosphites, Pyrophosphates, Silicates, Tannates
and Gallates, Thiocyanates, Urates, Valerates, etc.
xix
PAGE
vii
Xill
XIV
xv
XV
Xvi
17
20)
37
40
49
71
. 251
. 321
XX CONTENTS.
ANALYTICAL TABLE FOR ACID RADI€ALS
SYSTEMATIC ANALYSIS
ORGANIC CHEMISTRY ... .. 2 22
CHEMICAL TOXICOLOGY ... ....
EXAMINATION OF URINE AND CALCULI
OFFICIAL GALENICAL PREPARATIONS
OFFICIAL CHEMICAL PREPARATIONS
QUANTITATIVE MEASUREMENTS . . .
QUANTITATIVE ANALYSIS:
INTRODUCTORY REMARKS
VOLUMETRIC ANALYSIS
GRAVIMETRIC ANALYSIS... . . - ee es
DIALYsSIgs .......
APPENDIX :
THE ELEMENTS, THEIR SYMBOLS, AND ATOMIC
WEIGHTS .....- 2-2. es ee we
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CHEMISTRY:
GENERAL, MEDICAL, AND PHARMACEUTICAL,
INTRODUCTION;,'
MAN can neither create matter nor destroy matter, but he
can permanently alter its character. All that is burned is
thus altered, and nearly all that is eaten and digested is
thus altered. Man can in many cases bring about, or in a”
measure control, these permanent alterations which matter is
capable of undergoing; and in all cases he can investigate the
alterations in matter which are ever proceeding around him
in animal, vegetable, and mineral nature. The study of
these alterations in all their known length, and breadth, and
depth, is the study of natural science, of which Chemistry—
the study of most of the alterations—is one of the most com-
prehensive branches.
The infinite varieties of solid, liquid, and gaseous matter
of which our earth and atmosphere are composed may be so
altered by man as to be resolved into a few distinct substan-
ees appropriately termed Elements (E/ementum, first or con-
it principle of anything), for by no known means can
they be further decomposed. More than seventy of these —
elements have beeu proved to exist. Some, such as gold, occur
naturally in the uncombined state; but the greater number
are combined in so subtle a manner as to conceal them from
ordi methods of observation. Thus none of the common
of water indicate that it is composed of two ele-
ments, both gases, but differing much from each other; nor
enn the senses of sight, touch, and taste, or other ordinary
meana of examination, detect in their concealment the three
@lements of which sugar is composed. The art by which
| } Students using this book as a guide in following chemistry practi-
Hy should read the first four pages, and then commence work by pre-
All stadents should read the prefatory pages, especially
ye of “ Advice to Students," ae
a 17
18 INTRODUCTION.
these and all other compound substances are resolved into
their elements is termed the art of Chemistry, a name derived
possibly from the Arabic word kamai, to conceal.' The art
of Chemistry also includes the construction of compounds
from elements, the decomposition of compounds, and the con-
version of substances of one character into others of different
character. The science of Chemistry deals with the general
principles or leading truths relating to the elements, and to
the manner in which they severally combine ; with the obser-
vation of the phenomena which accompany chemical combi-
nations, interactions, and decompositions; and with the de-
scription of the general properties of the substances produced
during these changes.
From these few words concerning the nature of the art and
science of chemistry, it will be seen that in most of the oceu-
_pations that engage the attention of man, Chemistry plays an
important part—in few more so than in the practice of the
various departments of Medicine, especially the branches
termed Therapeutics * and Pharmacy,’
Air, water, food, drugs, and chemical substances—in short,
all material things—are composed, as stated, of Elements,
An intimate knowledge of the properties of the more impor-
tant Elements, both in the free (or uncombined) and in the
combined state, and of the various substances they form when
they have combined with each other; all attainable knowledge
'The idea that common metals contained valuable metals concealed
within them was the one seed from which chemical knowledge mainly
sprang. The men who endeavored to find the secret of such conceal-
ment were appropriately termed alchemists, and their efforts were spoken
of as alchemy (al kimia, from kamai, to conceal), Their persistent labors,
generation after generation, were unsucessful so far as the transmuta-
tion of haser metals into gold was concerned, vet were invaluable to pos-
terity ; for new substances were discovered and truths of nature unveiled ¢
from these discoveries further discoveries resulted, and thus grew the
still progressing branch of knowledge called Chemistry,
* Therapeutics (@epawewrecs, therapentikos, from @epareiw, therapend, T
nurse, serve, or cure) is the branch of medicine which treats of the ap-
plication of remedies for diseases. The therapeutist also takes cogni-
vance of hygiene—the department of medicine which respects the preser-
vation of health—and of dietetics, the subject of diet or food. By phar-
macology is understood the normal or physiological action of drugs, as
underlying the therapeutic action.
* Pharmacy (from ¢dppacor, pharmakon a drug) is the generic name for
the operations of preparing or compounding medicines, whether per-
formed by the Medical Practitioner or by the Pharmaceutical Chemist or
the Chemist and Droggist. It is also sometimes applied, like the corres
ponding term Surgery, to the apartment in which the operations are con-
ducted. /harmacoqnosy is the study of the crude drugs of the vegetable
and animal kingdoms,
METALLIC ELEMENTS, 19
oy eh or force (the chemical force or chemical affinity )
the elements contained in the compounds are held
together ; and the application of such knowledge to Pharmacy
wat Medicine, must be the objects sought to be attained by
thestudant of chemistry for whom especially this book has been
written.
Pei Elements.—Of the seventy or so known elements, the
‘ of about forty is essential for the proper comprehension
af Fortunately for sheaicad, and pharmaceutical
students ¢ these are of special medical or pharmaceutical
interest, hence such students while learning the science itself
ean study its es ene to medicine and pharmacy. ‘Two-
thirds of the are metals, one-third non-metals, The re-
mainder of the elements! are seldom met with in Nature, or
occur only in small quantities; and a number of them have
not received any practical application either in Medicine, Art,
or as Nanubtare
Before intimately y studying the elements, it is desirable to
fiequire some general notions concerning them : such a proced-
ure will also serve to introduce the practical student to his
Saat and make him better acquainted with the various
canta Recents. With regard to the metallic elements,
it may safely be assumed that the reader has sufficient know!-
edge for present purposes ; but little, therefore, need be said
them at this stage. He has an idea of the appear-
: Esight, hardness, ete., of such metallic ele-
ver, copper, lead, tin, zine, and iron. If he
knowledge of mercury, antimony, arsenic,
aluminiuf, magnesium, potassium, and
ild embrace the earliest opportunity of seeing
ing specimens of each of these metallic elements,
‘ate tee in the Appendix. (See also pp. 37 and 59.)
fer, s need not discourage the voungest student
hath <i F wha sa the same time a pupil in medicine or phar
- ney of a few phials, wine-glasses, or other similar
visas ls _ st hand, he may, by studying the follawing pages, learn
tions which are constantly occurring in the course of
ig 0 » medicines, understand the processes by which medicinal
ratte sen Bre zomgufictured, and detect udulterations, impurities, or
ite of ve ! Among the substances used in medicine will be
ne: ‘all the cliemical materials required, If, in addition, a
. st-tu os ind w few feet of glass tubing be procured, many of
periments described may be formed. For full lists of apparatus
sd chemical materials, see the prefatory pages.
20 NON-METALLIC ELEMENTS.
Non-Metallic Elements.— With regard to the non-metallic
elements, it is here supposed that the student has no general
knowledge. He should commence his studies, therefore, by
a series of operations as follows, on eight of their number,
OXYGEN.
Preparation.—Oxygen is the most abundant element in nature,
forming (in 4 state of combination) about one-half of the whole
weight of our globe. To obtain it for experimental purposes
all that is necessary is to apply heat to certain easily decompos-
able compounds containing oxygen, whereupon the latter is
evolved in the gaseous condition, There are several substances
which readily yield oxygen upon heating, but the crystalline salt
known as potassium chlorate is perhaps best fitted for the experi-
ment. The size and form of the vessel in which to heat the salt
will mainly depend on the quantity of oxygen required; but for the
purposes of the student the best is a fest-tube, an instrument in
constant use in studying practical chemistry. It is simply a tube
of thin glass, a few inches in length, and half or three-quarters of
an inch in diameter, closed by fusion at one end. It is made
of thin glass, in order that it may be rapidly heated or cooled
without risk of fracture, (See pictures of test-tubes in Figs, 3
and 4.)
Outline of the Process.— Heat potassium chlorate, Potassit
chloras, U.S. P., (say, as much as will lie on a twenty-five
cent piece in a test-tube held in the flame of a Bunsen burner
or spirit lamp. The salt first fuses—i.e., liquefies—and forms
a colorless liquid; and on further heating this liquid, gaseous
oxygen is quickly evolved. Before applying heat, however,
provision should be made for collecting the gas.
Collection of Gases (See in Fig. 3).—Procure a piece of glass
tubing about the thickness of till pen, and a foot or eigh-
teen inches long, and fit it to the test-tube by means of a
cork, (Longer tubes may be neatly cut to any sie by
smartly drawing the edge of a triangular file across the glass
at the required point, then clasping the tube, the seratch be-
ing between the hands, and pulling the portions asunder, the
pull being exerted as if to open out the crack which the file
has commenced. ) The tube is fixed in the cork through a
round hole made by the aid of a red-hot wire, _ or, better, by
a rat-tail file, or, best of all, by one of a set of -cork-borers—
pieces of brass tubing of different diameters, sharpened at
one end and having a flat head at the other. The cork and
OXYGEN. 21
test-tube must be fitted to each other accurately and closely,
but not so tightly as to break the test-tube. The long piece
of tubing should be bent to the most convenient shape for de-
livering the gas.
To Bend Glass Tubes.—Hol<d the part of the tube required
to be bent in any gas- or spirit-flame (a fish-tale gas-jet, for
example, Fig. 1), constantly rotating it, so that about an inch
Fre, 1.
Softening and bending glass tubes.
of the glass becomes heated. It willsoon begin to soften, and
by the gentle pressure of the fingers, it can then be made to
aasume any required angle. In the present case, the tube
should be heated at about four inches from the extremity
to which the cork is attached, and bent to an angle of 90
degrees (Fig. 2). A similar bend may be mace near the other
end, and the short piece of straight tubing should then be
eut off The cut ends should finally
be rounded off by holding them in Fra, 2,
the fame until the glass softens. The
finished tube has the shape shown in
Fig. 3.
it the cork and bent tube into
the teat-tube ; the apparatus will then ag
be ready for delivering gas at a con- Yj
venient distance from the heated por- ©
tion of the arrangement. To collect
the oxygen, have ready three or four
(or small wide-mouthed bot-
thes) quite filled with water, and in-
v in a basin or other vessel, also
containing water, taking care to keep
the mouths of the filled tubes a little
below the surface. Now apply heat
t the chlorate contained in the test-
tube, and so arrange the open end of
the bent tube under the water that the gas which presently
extapes with effervescence from the melted chlorate may
22 NON-METALLIC ELEMENTS.
pass out from the free end of the tube, and may bubble
into and gradually fill the previously water-filled inverted
test-tubes. The first tubeful may be rejected, as it probably
consists of litthke more than the air which was originally in
Fra, 3.
na ona
ines
—)
— |
——=|
=
Hitt
This picture represents the preparation, collection, and storage of small
quantities ofoxygengas, <A lest-tube and bent glass tube, connected by menns
of a perforated cork, are supported by the arm ofan iron stand. (The appara-
tus Might be held by two fingers.) The test-iube is heated Ina’ Bunsen” fame.
The spirit-lamp shown at back might be used Instead.) Thegas evolved from
the heated substance displaces water from an inverted test-tube, Spare tuboe
in a test-tube rack are af band, and tubes already filled with the gas have been
set aside until wanted. Asetof cork-borers, a round file, « triangularfile and
a test-tube cleaning brush are lying on the table or student's benth, Below
are cupboards for apparatus, above are bottlos containing testing liquids, ete,
24 NON-METALLIC ELEMENTS.
small scale, and Wroblewski obtained it in larger quantity as
a transparent fluid, closely resembling water in appearance,
but slightly bluer ; Dewar has now liquefied it in large quan-
tities, and has also ‘obtained it in the solid condition. Obvi-
ously oxygen is not very soluble in water, or it could not be
collected by the aid of that liquid. It is soluble, however, to
a certain extent, about 3 volumes dissolving in. 100 of water
at ordinary temperatures. When any ordinary sample of cis-
tern or river water is heated, or subjected to greatly reduced
pressure, numerous small bubbles of gas, containing a consid-
erable proportion of oxygen, gradually escape from it. The
presence of dissolyed oxygen in river and sea water is essen-
tial for the respiration of fishes.
To observe the relation of oxygen to combustion, remove
one of the tubes from the water, by placing the thumb over
its mouth, and apply for a second a lighted wood match to the
orifice ; the gas will be found to be incombustible. | Extin-
guish the flame of the match, and then quickly introduce the
still incandescent carbonized extremity of the wood well in-
side the test-tube; the wood will at once burst into flame,
owing to the extreme violence with which oxygen supports com-
bustion. These tests of the presence of free oxygen may also be
applied at the extremity of the delivery-tube whilst the gas is
being evolved. (It is desirable to retain two tubes of the gas
for use in subsequent experiments; also one tube in which
only one-third of the water has been displaced by oxygen. )
Relation of Oxygen to Animal and Vegetahle Life.-—Not only
the carbon at the end of a piece of charred wood, but any other
substance that will burn in air (which, as will be seen presently,
in diluted oxygen) will burn more brilliantly in pure oxygen.
The warmth of the bodies of animals is kept up by the continuous
burning of the tissues in the oxygen of the air, drawn into the
system through the lungs. The product of this combustion is
exhaled into the air as a gaseous compound of carbon and oxygen
termed carbonic anhydride, a gas which, in sunlight, is absorbed
by and decomposed in the cells of plants with fixation of carbon
and liberation of the oxygen, Thus, too, is the atmosphere kept
constant in composition,
Memorandum,—At present it is not advisable that the reader
should trouble himself with the consideration of the chemical
action which occurs either in the elimination of oxygen from
its compounds, or in the separation of any of the following non-
metallic elements from their combinations. It is to the properties
of these elements themselves, especially in their free, or uncom-
HYDROGEN. 25
bined, condition, that he should at present restrict his attention.
Working thus from simple to more complex facts, he will in due
time find that the comprehension of such actions as occur in the
preparation of these few elements will be easier than if he
attempted their full study now.
HYDROGEN.
Preparation and Collection.—The element Hydrogen, in
the uncombined state, is also a gas.’ It is obtainable frora its
commonest compound, water (of which about one-ninth by
weight is hydrogen), by the agency of hot zine or iron, but
more conveniently by the action of either of these metals on
cold dilute sulphuric acid. The apparatus used for making
oxygen may be employed for this experiment; but no lamp
is required. Place several pieces of thin zinc* in the gener-
ating tube (Fig. 4), or in a common glass bottle (Fig. 5), or
flask, and cover them with water. The collecting-tubes
(these alsomay be wide-mouthed bottles) being ready, add
concentrated sulphuric acid (oil of vitrol) to the zine and
water, in the proportion of about 1 volume of acid to 5 of
water, and fit on the delivery-tube; or pour the acid down
1 Graham obtained alloys of hydrogen with palladium and other metals
compounds in which several hundred times its bulk of gas is retained
by the metal in raeno or even at a red heat. This was regarded as phys-
ical confirmation of the opinion long held by chemists, that hydrogen is
& gaseous metal. Graham termed it hydrogeninm, other chemists hydrinm,
and considered ite relative weight in the solid state to be nearly three-
fourths that of water. Olszewski claimed to have liquefied hydrogen in
1695, It has been liquefied by Dewar, who finds its critical temperature
(i. «, the temperature to which it must be cooled before it is possible to
convert it into the liquid state by the application of any pressure, how-
ever 1) to be approximately—233° C., and its boiling point—243° C,
Helium.— More than thirty years ago, Frankland and Lockyer, to ac-
count for a certain yellow line in the solar spectrum, assumed the exist-
ence of a separate element which they termed helinm. In 1805 Ramsay
found a new element in the mineral clevite giving an iguition a yellow
line in the spectrum, probably identical with that just alluded to. To
this new terrestrial element he gave the name helium. Ramsay, Collie,
and Trivers afterwards found helium in many minerals, often accom-
panied by hydrogen, though it seems rather to have analogies with argon,
another comparatively recently discovered element which will be re-
ferred to under nitrogen. Many minerals yield gases when heated, and
even contein sin cavities. .
The best form is granulated zine prepared by heating zine in an iron
| Over a fire, and immediately the metal is fused, pouring it ina slow
stream into nm pail of water from a height of & or 10 feet. Each drop of
mine thos yields 4 thin little bell, which, for its weight, presents a large
' to the action of the acid liquid. If the melted zine becomes too
hot, the little bells will not be formed. At race of iron in the zine greatly
fnereases the rate at which the hydrogen is evolved.
NON-METALLIC ELEMENTS.
such « funnel-tube' as is shown in Fig. 5; the hydrogen at
once escapes with effervescence from the fluid. Having re-
jected the first portions (or having waited until the air orig-
Preparation of hydrogen.
inally in the bottle may be considered to be all expelled),
collect four or five tubes of the gas in the manner described
under oxygen.
Notes.—In making larger quantities, bottles of appropriate size
may be employed, Other metals, notably potassium and sodium,
liberate hydrogen the moment they come into contact with water ;
but the processes are not economical, and the action is danger-
ously violent,
Properties.—Hydrogen, like oxygen, is colorless, odorless,
and tasteless. If iron be used to generate the gas, it has a
marked smell; but this is due to impurities derived from the
iron.
Apply a flame to the mouth of the delivery-tube, but not
until it is plain that the brisk effervescence of hydrogen must
have resulted in the driving out of all air from the generating
tube or bottle, jor the mixture of hydrogen and air may explode.
Ignition of the hydrogen ensues, showing that, unlike oxygen,
it is combustible.
Plunge a lighted match well into a tube (or wide-mouthed
bottle) containing free hydrogen; the gas is ignited, but the
match becomes extinguished. This shows that hydrogen is
not a supporter of ordinary combustion.
' Funnel-tubes may be purchased of the apparatus-maker; or, if the
pupil has access to a lable blowpipe, and the advantage of a tutor to di-
rect his operations, they may be made by himself,
HYDROGEN, 27
Hydrogen in burning unites with the oxygen of the air
and forms water, which may be condensed on a cool stiee a or
other surface. Prove this by holding a glass vessel a few
inches above a hydrogen-flame. In burning the hydrogen
contained in one of the tubes or bottles, the flame is best seen
when the tube is held mouth upward, and water poured in
so as to expel the gas gradually.
If, instead of this gradual combination of the two elements
oxygen and hydrogen, they be mixed together in the right
proportions and then ignited, they will rapidly combine, and
explosion will result. Prepare a mixture of this kind by
filling up with hydrogen a test-tube from which one-third of
the water has already been expelled by oxygen. Remove
the tube from the water, placing a finger over its mouth, and
having a lighted match ready, apply the flame; explosion
ensues, owing to the instantaneous combination of the whole
bulk of the two elements, and the expansive force of the
highly heated steam produced. If anything larger than a
test-tube is employed in this experiment, it should be an
aérated water bottle, or some such vessel equally strong.
Notes —These gases thus unite at a temperature far higher than
that of boiling water, two volumes of hydrogen and one of oxy-
gen yielding two of gaseous water (steam).
The noise af such explosiona is caused by concussion between the
suddenly expanded gaseous body and the air.
The force of the explosion, or, in other words, the pressure of
the suddenly heated and therefore suddenly expanded steam, is
below that necessary to break the test-tube. Some pressure,
however, is exerted; and hence the necessity of the precaution
previously suggested, of allowing all the air which may be in a
hydrogen-apparatus to escape before proceeding with the experi-
ments, If a flame be applied to the delivery-tube before all the
air is expelled, the probable result will be ignition of the mixture
of hydrogen and oxygen (of the air) and consequent explosion,
But even in this case the generating vessel is not often fractured
unless it be large and of thin glass, the ordinary effect being that
the cork is blown out, and the delivery-tube broken on falling to
the ground.
Hydrogen ia a constituent of all the substances burned for pro-
ducing artificial light, such as solid fats, oil, and coal-gas, The
explosive force of large quantities, such as a roomful, of coal-gas
and air is well known to suffice for blowing out thut side of the
room which offers least resistance. =
The composition of water can be proved analytically as well as
28 NON-METALLIC ELEMENTS,
synthetically, by passing'a current of electricity through dilute
sulphuric acid (electrolysis, from Ai, /uo, I loose, or I decom-
pose). During the passage of the current, hydrogen and oxygen
are liberated in the proportions in which they are present in
water, twice as much hydrogen as oxygen, by volume, being
produced. The quantity of sulphuric acid remains the same at
the end us at the beginning of the experiment, the quantity of
water haying alone diminished.
COMBUSTION (from comburo, I burn),—The experiments with
hydrogen and oxygen illustrate the true character of combustion,
Whenever chemical combination is sufficiently intense to be ac-
companied by heat and light, the materials are said to undergo
combustion. Combustion only occurs at the line of contact
of the combining bodies; a jet of oxygen will burn in an
atinosphere of hydrogen quite as easily as a jet of hydrogen in
oxygen. A jet of air (diluted oxygen) will burn as readily in a
jar of coal-gas as a jet of coul-gas burns in air; each is combus-
tible, each supports the combustion of the other, Hence the
terms combustible and supporter of combustion are merely conven-
tional, and only applicable so long as the circumstances under
which they are applied remain the same. In the case of sub-
stances burning in air, the conditions are, practically, always
the same; hence no confusion arises from regarding air as the
great supporter of combustion, and bodies which burn in it as
being combustible,
Fig, 6.
Structure of candle-flame. “Bunsen,” or sire, burner,
Structure of Flame.—A candle-flame (Fig. 6) or oil-flame is
composed of intensely heated material; the central portion is un-
burnt gas, the next envelope is formed of partially burnt and
very dense gaseous und solid particles sufficiently highly heated
to give light, and the outer cone of completely burnt gases. In
the figure the sharpness of limit of these cones is purposely
HYDROGEN. 29
somewhat exaggerated. Air made by any mechanical contri-
vance to mix with the gas in the interior of a flame at once burns
tip, Or perhaps prevents the formation of, dense gases; giving a
hotter, but non-luminous jet. The air-gas lamps (Fig. 7), or
“Bunsen” gas-burners, commonly used in chemical laboratories,
are constructed on this principle; their flame has the additional
advantage of not vielding a deposit of soot.
In the air-gas burner coal-gas escaping from a small orifice at
the bottom of the upright tube draws in and mixes with rather
more than twice its volume of air (supplied through adjacent
holes). The mixture, when kindled, only burns at the end of the
upright tube, and not within it, partly because the metal of the
burner, by conducting heat away, cools the mixture below the
temperature at which it can ignite; partly because the velocity
with which the mixture flows out is greater than the rate at which
such a mixture ignites; and partly because the proportion of air
to gas in the mixture is insufficient for perfect combustion, the
external air immediately surrounding the flame contributing ma-
terially to the complete combustion of the gas. In the Dary
cafety-lamp advantage is taken of the rapidity with which a sur-
face of wire gauze conducts away heat; a wire-gauze cage sur-
rounds an oil-flame; an inflammable mixture of gas (fire-damp)
and air can pass through the gauze and burn inside; but the
flame cannot, ordinarily, be communicated to the mixture out-
side, because the metal of the gauze and of the other parts cools
down the gas below the temperature at which combustion can
continue.
oper of Hydrogen (continued ).—Gaseous hydrogen
is the lightest substance known. It is used for filling bal-
loons, but has been, to some extent, superseded by coal-gas
because coal-gas, though not so light, is cheaper and more
easily obtained. The lightness of hydrogen may be rendered
evident by the following experiment:—Fill two test-tubes
with the gas, and hold one with its mouth downwards and
the other with its mouth upward. The hydrogen will have
1 from the latter in a few seconds, whereas the former
will still contain the gas after the lapse of many seconds.
This may be proved by applying a lighted match to the
mouths of the tubes,
The relative weight or specific gravity of oxygen is nearly six-
teen times that of hydrogen. A vessel holding one grain of hy-
yen will hold nearly sixteen grains of oxygen. The relution
of weight of hydrogen to air is as 1 to 14.44, or as 0.0693 to
1,0, One grain of hydrogen by weight measures alk mut 27 fluid
NON-METALLIC ELEMENTS.
ounces, and, therefore would about fill a common wine-bottle.
Such a bottle would, at ordinary temperatures, hold about 144
grains of air, or about 16 grains of oxygen,
Memorandum.—lIt is desirable to retain two tubes of hydrogen
for use in subsequent experiments.
Dirrusion oF Gases.—Hydrogen cannot be kept in such ves-
sels as the inverted test-tube of the above experiment ; for, though
much lighter than air, it diffuses downward into the air, while the
air, though much heavier, diffuses upward into the hydrogen.
This power of diffusion is possessed by all gases. The rates of dif-
fusion of the different gases are inversely proportional to the
square roots of the densities of the gases (Graham). Thus hydro-
gen diffuses four times faster than oxygen. The great and impor-
tant property of diffusion suggests that the particles of gases are
always moving, never at rest; how otherwise cou/d gases diffuse
into each other as they do, notwithstanding the opposing influ-
ence of gravitation? Diffusion strongly supports this (Clausius’s)
kinetic («ivéa, bined, I move, or put in motion) theory of the
physical condition of gases,
PHOSPHORUS.
Appearance and Source.—Phosphorus (Phosphorus, U. 8. P-.)
is a solid element, in appearance and consistence resembling
white wax ; but it gradually becomes yellow by exposure to light.
It is a constant constituent of bones, and may be prepared from
them by a process which will be described subsequently,
Caution. —Phosphorus, on account of its great affinity for oxy-
gen, takes fire very readily in the air, and should therefore be
kept under water. When wanted for use, it must be cut under
waiter, Itis employed in tipping lucifers though red or amor-
phous phosphorus is \eas objectionable for this purpose.
Experiment,—Dry a piece of ordinary phosphorus, about
the size of a pea, by quickly and carefully pressing it between
the folds of porous (filter or blotting) paper; place it on a
plate, and ignite it by touching it with a piece of warm wire
or wood. The product of combustion is a dense white suffo-
eating smoke, which must be confined at once by placing an
inverted tumbler, or beaker, or other similar vessel over the
phosphorus. The fumes rapidly aggregate, and fall in white
flakes on the plate. When this has taken place, and the
phosphorus is no longer burning, moisten the powder with a
drop or two of water, and observe that some of the water is
converted into steam, an effect due to the intense affinity with
which another portion of the water and the powder have com-
bined, with the evolution of heat.
NITROGEN, 3l
The powder produced by the combustion of phosphorus is
termed phosphoric anhydride ; the combination of the latter with
the elements of water produces a variety of phosphoric acid which
dissolves in the water and forms, on standing, a dilute solution of
ordinary phosphoric acid. The Diluted Phosphoric Acid of the
Pharmacoperia is a similar solution, made in a somewhat different
way, und of definite strength.
NITROGEN.
Source.—The chief source or this gaseous element is the
atmosphere, nearly four-fifths of which consists of nitrogen
(whilst roughly one-fifth is oxygen ).
Preparation.— Burn a piece of dry phosphorus, the size of
& pea, in a confined portion of air. The oxygen is thus re-
moved, and the nitrogen remains. The readiest mode of per-
forming this experiment is to fix a piece of earthenware (the
lid of a small porcelain crucible answers very well) on a thin
iece of cork, so that it may float in a dish of water (Fig. 8).
lace the dry phosphorus on the lid, ignite with a warm rod,
and then invert a tumbler, or any glass vessel of about a half-
pint capacity, over the burning phosphorus, so that the mouth
ofthe glass may dip into the water. Let the arrangement
rest for a short time, for the flakes of phosphoric anhydride to
subside and dissolve in the water, and then decant the gas into
test-tubes as indicated in Fig. 9, using a tub or other vessel of
Fig, 8.
Decantation of gases,
sufficient depth to admit of the glass containing the nitrogen
being turned on one side without air gaining access.
Larger eee of nitrogen may be obtained in the same way.
bles, a8 sulphur or « candle, might be used to burn
NON-METALLIC ELEMENTS.
out the oxygen gas from the air, but none answer so quickly ar
completely as phosphorus, added to which, the products of the
combustion would not always be dissolved by water, but would
main mixed with the nitrogen.
Memorandum.—The statement concerning the composition
the air is roughly confirmed in isolating nitrogen, about one-fift
of the volume of the air originally in the glass vessel havir
disappeared, its place being occupied by water.
Properties.—Nitrogen, like oxygen and hydrogen, is colo
less, tasteless, and odorless. By pressure, Cailletet and Picte
condensed it toa liquid. Wroblewski and Olszewski obtaine
it some quantity as a nearly colorless, transparent fluid, whie
congeals, by its own evaporation, to a white snow-like soli¢
It is only slightly soluble in water. /'ree nitrogen is distir
guished from most other gases by the absence of any chara
teristic or positive properties. Apply a flame to some co
tained in a tube; it will be found to be incombustible, Im
merse a lighted match in the gas; the flame is extinguished
showing that nitrogen is a non-supporter of combustion,
Nitrogen is nearly fourteen times as heavy as hydrogen.
The free nitrogen in the air acts as a dilutent of the energeti
oxygen, with which it forms merely a mechanical mixture.
The air is nearly fourteen and a half (14.44) times as heavy a
hydrogen. It may be liquefied and solidified, Its average com
position, including minor constituents (which will be referred t
subsequently), is as follows :—
Composition of the Atmosphere,
In 100 volumes,
CPOE és hie Eas sk ae tw . ROBB
Ce i Ae ms « TORR
Argon Y Pee £ 2 O4
Carbonic anhydride . Nth atts. a. Pt ; 084
A i ae or
Ammonia, nitric acid, carburetted
hydrogen, hydrogen, ozone, helium, } traces,
krypton, neon, xenon. , -)
Sulphuretted hydrogen, sulphurous } traces in
OS! a a
Pure dry air, freed from carbonic anhydride, ete., is remarkabl
constunt in composition, and contains approximately :—
Percent. Percent.
by volume. by weight.
Nitrogen (including argon, etc.) . . 79,04 76.9
Oxygen r a rT a * * o * ' # 20), 96 Ph ]
CHLORINE, 33
- Free Nitrogen and Combined Nitrogen,
Notwithstanding the comparative inactivity or negative charac-
ter of nitrogen in its free condition—that is, when uncombined
with other elements—this element, when combined with hydro-
gen, carbon, oxygen, etc., is a constituent of a large number of
important substances, including the ammonium compounds, the
various cyanogen compounds, the extensive group of salts called
nitrates, the valuable medicinal agents known as alkaloids, the
various albuminoid and collagenic matters characteristic of the
tissues of — and plants, and so forth. Free nitrogen is not,
however, altogether inactive, for the nitrogen of the air appears to
be absorbed and assimilated by some plants—certain rare
taining more nitrogen than the soil and manure in which they
grew. The absorption is effected by means of nodules which oc-
cur on the roots of clover and other leguminous plants ; these are
the dwelling-places of microérganisms, and it is through their
ageney that the soil in which such plants grow becomes richer in
nitrogen. Experiments have been made with a view to inducing
these organisms to live on the roots of graminaceous plants, for if
this, could be done a great saving of artificial manures could be
ARGON. KRYPTON. NEON.
Tt has long been known that when nitrogen is prepared from
atmospheric air, the gas obtained is slightly heavier than nitrogen
pared from nitrates or from ammonia, The investigations of
Rayleigh and Ramaay have proved that this is due to the presence
of another gas, heavier than nitrogen, to which, on account of
it# apparent chemical inactivity, they gave the name argon (a,
without, fpyov, ergon, work). Its density is about 19, It is
sheen in atmospheric air to the extent of nearly 1 percent.
ly a compound of argon with carbon has been obtained by
the passage of electricity between thin carbon poles in an atmos-
phere of argon; and experiments show that it probably combines
with the vapor of magnesium ata very high temperature. Argon
and helium oceur with nitrogen in the gases of many naturally
Ramsay obtained another element from atmospheric air, to
which he gave the name Krypton (xpirmrroc, kryptos, hidden);
traces only are present. Rameay and Travers subsequently an-
nounced the presence of another element, Neon (vcore, neos, new),
CHLORINE.
Source.—The chief source of this element is common salt,
more than half of which is chlorine.
3
3j4 NON-METALLIC ELEMENTS.
Preparation.—A bout a quarter of an ounce each of salt
and of black munganese oxide are mixed, placed in a test-
tube, and covered with water ; on adding a small quantity of
sulphuric acid, evolution of chlorine commences. For the
mode of collection see the following paragraphs.
Another process.—As the action of the sulphuric acid on
the salt in the above process is mainly to give hydrochloric
acid, the latter acid (about 4 parts) and the black mangan-
ese oxide (about 1 part) may be used in making chlorine,
instead of salt, sulphuric acid, and black manganese oxide.
Collection and Properties.—F ree chlorine is a suffocating
vas. Care therefore must be observed in experimenting with
this element. As soon as its penetrating odor indicates that
it is escaping from the test-tube, the cork and delivery-tube
(similar to that used in making oxygen) should be fitted on,
and the gas led to the bottom of another test-tube containing
water (Fig. 10). When thirty or forty small bubbles have
Fig. 10.
Preparation of chlorine.
passed, their evolution being assisted by slightly heating the
generating tube, the latter should be removed to the cup-
board usually provided in laboratories for performing opera-
tions with noxious gases, or be dismounted and the contents
carefully and rapidly washed away. The water in the col-
lecting-tube will now be found to smell of the gas, chlorine
being soluble in about half its bulk of water.
Larger quantities may be made from hydrochloric acid and
black manganese oxide (4 to 1) in a flask fitted with a delivery-
tube, the flask being supported over a flame by the ring of a
CHLORINE. on
retort-stand (Fig. 11), A piece of cardboard on the neck of the
colleeting-bottle, as indicated in the figure, retards diffusion of
chlorine from the bottle during the process of collection,
Memorandum,—F \asks and similar glass vessels are less liable
to fracture if protected from the direct action of the flame by being
placed on a piece of wire gauze about 6 inches square, or on a
sand-bath, that is, a saucer-shaped tray of sheet iron on which a
thin layer of sand is placed.
_ During these manipulations the operator will have noticed
that chlorine is of alight yellowish-green color. The tint is ob-
servable when the gas is colleeted in large vessels. As chlorine
is soluble in water (24 vols. in 1 vol. at 60° F., 15.5° C.), it can-
not be economically stored over that liquid. Being, however,
nearly two and a half times as heavy as air, the gas may be col-
lected by simply allowing the delivery-tube to pass to the bottom
of a dry test-tube or dry bottle (Fig. 11).
An important property of free chlorine is its bleaching
wer. Prepare a colored infusion by placing a few chips of
logwood in a test-tube half full of hot water. Pour off some
this red infusion into another tube and add a few drops of
chlorine-water; the red color is rapidly destroyed.
Free chlorine readily decomposes offensive effluvia; it is one of
the most powerful of deodorizers. It also decomposes putrid and
infectious matter; it is one of the best of disinfectants, (Antiseptics
are substances which prevent putrefaction. )
Combination of Hydrogen with Chlorine, forming Hydro-
chloric Acid. —If an opportunity occurs of generating chlorine
in a closed chamber or in the open air, a test-tube, of the
same size as one of those in which hydrogen has been retained
from a ge operation, is filled with the gas. The hydro-
sn-tube is then inverted over that containing the chlorine,
ye mouths being kept together by encircling them with a
finger. After the gases have mixed, the mouths of the tubes
are Te brought into contact with a flame, when explosion
occurs fames of a compound of hydrochloric acid gas
with the moisture of the air are formed, The Hydrochloric
Acid of pharmacy (Acidum Hydrochloricum, U.S. P.) isa
solution of this gas (made in a more economical way) in
The foregoing experiment affords evidence of the powerful
iftinity of chlorine and hydrogen for each other. Chlorine dis-
il vec do water will, in sunlight, slowly remove hydrogen from
ob NON-METALLIC ELEMENTS.
some of the water and liberate oxygen. The bleaching power of
chlorine is generally referred to this indirect oxidizing effect which
it produces in presence of water; for dry chlorine does not bleach.
Density.—Chlorine is more than 35 times as heavy as hy-
drogen, A wine-bottle would hold about 35 grains.
SULPHUR, CARBON, IODINE.
The physical properties (color, hardness, weight, ete.) pos-
sessed by these elements, when they are in the free state, are
probably familiar to the student. Some of their leading
chemical characters will also be understood when afew facts
concerning each are made the subject of experiment.
Sulphur.— Burn a small piece of sulphur ; a penetrating odor
is produced, due tu the formation of a colorless gas. This
product is a chemical compound formed by the union of the
oxygen of the air withthe sulphur, It is termed sulphurous
anhydride (or sulphurous acid gas),
Carbon, in a more or less pure condition, is familiar, in the
free form, as soot, coke, charcoal, graphite (or plumbago, pop-
ularly termed blacklead), and diamond. The presence of
combined carbon, in wood and in other vegetable and animal
matter, is at once rendered evident by heat. Place a little
tartaric acid on the end of a knife ina flame; the blackening
that. occurs is due to the separation of carbon. The black
matter at the extremity of a piece of half-burned wood also
is free carbon,
Carbon, like hydrogen, phosphorus, and sn)phur, has a great
affinity for oxygen at high temperatures. A striking evidence of
that affinity is the evolution, during its combustion, of sufficient
heat to make the materials concerned red or even white-hot,
When ignited in the diluted oxygen of the air, carbon simply
burns with a moderate glow, as seen in an ordinary coke or char-
coal fire; but when ignited in pure oxygen, the intensity of its
combustion is greutly exalted. The product of the combination
of the two elements, if the oxvgen be in excess, is an invisible gas
termed carbonic anhydride (or carbonic acid gas); if the carbon
be in excess and the temperature very high, another invisible gas,
termed carbonic oxide, results,
Iodine.—A prominent chemical characteristic of free
iodine is its great affinity for metals. Place a piece of iodine,
about the size of a pea, in a test-tube with a small quantity of
water and add a few iron filings or smal! nails. On gently
THE ELEMENTS. yi
warming this mechanical mixture, or even shaking, if longer
time be allowed, the color and odor of the iodine disappear ;
it has chemically combined with the iron—a chemical eom-
pound has been produced. If the liquid be filtered, a clear
aqueous solution of the compound of the two elements is ob-
tained.
This compound is an iodide of iron. Its solution, made as
above, and mixed with sugar, forms, when of a certain
strength, the ordinary Syrup of Ferrous Iodide of pharmacy
(Syrupus Ferri Iodidi, U. S. P.). The solid iodide is ob-
tained on remoying the water of the above solution by evap-
oration.
Sulphur and Jron, also, when very strongly heated, chemically
combine to form a substance which has none of the properties of a
mixture of sulphur and iron—that is, has none of the characters
of sulphur and none of iron, but new properties altogether. The
product is termed Ferrous Sulphide. Its manufacture and uses
will be alluded to in treating of the compounds of iron ; it is men-
tioned here as a simple but striking illustration of the difference
between a chemical compound and a mechanical mixture,
Aja Yan, y THE ELEMENTS, © | Ayu.
From the foregoing statements a general idea will have
been obtained of the nature of several of the more frequently
occurring elements. Some additional facts concerning them
may be gathered from the following Table, which gives the
origin of the names of a number of the elements ;—
Aluminium . The metallic basis of alum was at first confounded
with that of irom sulphate, which was the alum of
the Romans, and was so-called in allusion to its
tonic properties, from alo, I wowrish.
[Ammonium] This body is not an element; but its components
exist in all ammonical salts, and apparently play
the part of such clements as potassium and sodium.
Sal ammoniac (ammonium chloride) was first ob-
tained from near the temple of Jupiter Ammon in
Libya; henee the name. a. Se
Zrifc (stibi), OF erie (stimmi), was the Greck name
for the native antimony sulphide, The word an-
timony is said to be derived from dvri (anti)
againal, and moine, French for monk, from the fret
that certain monks were poisone él by it,
From a, Withont : épyor (e rgon), work.
Aprevinse (arsenikon ), the Greek name for orpi- -
ment, an arsenic sulphide. C ‘ommon white arsenic
is arsenic trioxide.
Boron .
Bromine
Cadmium
Calcium
Carbon .
Carium.
Chlorine .
Chromium .
Cobalt. .
THE ELEMENTS,
From fapvs ( barts) heary, in allusion to the high spe-
cific gravity of “heavy spar,"’ the most common
of the barium minerals,
Slightly altered from the German Wismuth, derived
from Wiesematte, “a beautiful meadow," a name
given to it originally by the old miners in allusion
to the prettily variegated tints presented by the
freshly exposed surface of this crystalline metal,
From berak or bouwrak, the Arabic name of horas, the
substance from which the element was first ob-
tained.
From fpayos (bromos), a stink, It bas an intoler-
able odor,
Kadueia (kadmeia) was the ancient name of calamine
(xine carbonate), with which cadmium carbonate
was long confounded, the two often occurring
together,
Calx, lime, calcium oxide,
From carbo, coal, which is chiefly carbon,
Discovered in 1503, aud named after the planet
Ceres, which was discovered on Jan, 1, 1801.
From yAwpds (chidros) green, the color of this ele-
ment.
From ypwye (chrima) color, in allusion to the char-
acteristic appearance of its sults,
Cobalus, or Kobold, was the name of a demon sup-
posed to inhabit the mines of Germany. The
ores of cobalt were formerly troublesome to the
German miners, and hence received the pame
their metallic radical now bears.
Copper (Cuprum) From (yprus, the name of the Mediterranean island
Fluorine .. =.
Gold (Aurum) .
Hydrogen. .
Iodine .. =.
Iron (Ferrum)
Lead (Plumbum)
Lithium ,
Magnesium ..
Manganese
where this metal was first worked.
From fluo, [ flow. Calcium fluoride, its source, is
commonly used as a flux in metallurgic opera-
tions.
Aurum (Latin) from a Hebrew word signifying the
color of fire.
(old ; «similar word is expressive of bright yellow in
several old languages.
From ¢éep (hud6ér) water, and yéveou (Genesis), gener-
ation, in allusion to the product of its combustion
in air,
From ior (ion) @ violet, and «ldos (eidos) likeness, in
reference to the color of its vapor,
Prehistoric. The spelling may be from the Saxon
iren, the pronunciation from the Gothic “itarn.”
The derivation is perhaps Aryan; it probably
originally meant metal.
The Latin expresses “ something heavy”; the Saxon
Led has a similar signification.
From Ai@eos (litheios) stony, in allusion to its sup-
posed existence in the mineral kingdom only.
From Magnesia, the name of the town (in Asia
Minor) near which the substance now called
“native magnesitim carbonate" was first dis-
covered,
Probably the slightly altered word magnesia, with
Whisee compounds those of Manganese were con-
founded till 1740,
DERIVATION OF NAMES, 39
Mercury . . . Hydrargyrum, from tbep (huddr) water, and adpyuvpo¢
(Hydrargyrum) (arguros) silver, in allusion to its liquid and lus-
trous characters. Mercury, after the messenger
of the gods, on meccount of its susceptibility of
motion. The old naue quicksilver also indicates
its realy mobility and silvery appearance,
Nickel from nil, worthless, Nickel ore wus formerly
called Kupfernickel, false copper. When a new
element was found in the ore, the name nickel
was retained for it,
From vitpoy (nitron) and yeveow (wenesis) generation,
i. €., generator of nitre.
From ogi¢ (oxiis) acid, and yeveris (genesis) generation,
i. ¢, generator of acids, When first discovered it
wus supposed to enter into the composition of all
acids,
tes (phos) light, and ¢dpeaex (pherein) to bear, The
light it emits may be seen on exposing it in a dark
room.
From platina (Spanish), diminutive of plata, silver.
Itsomewhat resembles silver, but ts less white and
lustrous,
Kalium from kali, Arabic for ashes (see Sodium).
Manufactories in which compounds of potassium
and allied sodium sults are made, are called a/kali-
works to this day. Polassinm, from potash. Pot-
ash so-called because obtained by evaporating the
lixivium of wood-nshes in pots.
Silicon . .- From siler, Latin for flint, which is nearly all silica
(silicon oxide}.
Silver .. “Apyypos (arguros) silver, from apyts (argos) white.
(Argentum) Words resembling the term ¢i/ver occur in several
langnages, and indicate a white appearance.
Sodium (Natrium) Nairivm, from netron, the old name for certain
natural deposits of sodium carbonate. Sodimm,
from soda, the name originally given to the resi-
due of the combustion of marine plants. Soda
ashes were chemically distinguished from pot-
ashes by Duhamel in 1736, Previously both were
simply kali or ashes from two different sources,
Sir Hompbhry Davy first isolated the two metals,
in 1807.
This name is commemorative of Stronfian, a mining-
village in Argyleshire, Scotland, in the neighbor-
hood of which the mineral known as strontianite,
or strontium carbonate, was first found.
From #a/, a salt and wip (ptr) fire, indicating its com-
bustible qualities. Its common name, brimstone,
has the same meaning, being the slightly altered
Saxon word, hr ynatone, i. @. “4 burnstone,
Both words wre possibly corruptions of the old Brit-
ish word slacn, or the Saxon word stan, o stone.
Tin wwe first Alsciverod in Cornwall, and the ore
(an oxide) is called finstone to the present day.
From Ger, Zinn, tin, with which Zine seems at first
to have been confounded,
40 NUMERICAL AND PHYSICAL MATTERS.
QUESTIONS AND. EXERCISES,
Distinguish between the art and the science of chemistry.—Of how
muny elements is terrestrial matter composed? Enumerate the chief
non-metallic elements,—Describe a process for the preparation of oxy-
geu.—How are gases usually stored ’—Mention the chief properties of
oxygen.— What is the source of animal warmth ?—State the proportion of
oxygen in air—Is the proportion constant, and why ?—Give a method
for the elimination of hydrogen from water.—State the properties of
hydrogen,—Whzy is a mixture of hydrogen and air explosive ?—Explain
the effects producible by the ignition of large quantities of coal-gas and
uir.— What is the nature of combustion ?—Delfine a combustible and a su
porter of combustion,— Describe the structure of flame,—State the principle
of the Davy safety-lamp.—In what proportion is hydrogen lighter than
oxygen /—What do you mean by diffusion of gases ?—State Graham's law
concerning diffusion.—Name the source of phosphorus, and give its char-
acters.—Why does phosphorus burn in air?—What gas remains when
ignited phosphorus has removed all the oxygen from a confined portion
of air?—Mention the properties of nitrogen.—What office is fulfilled by
the nitrogen of the air?—State the proportions of the chief constituents
of air.— Mention the minor or occasional constituents of air.—W hat is the
proportion by weight of nitrogen to oxygen in the atmosphere ?—Give
the specific gravity of nitrogen.—How is chlorine prepared ?—Enumerate
the properties of chlorine.—Define the terms deolorizer and disinfeotant.—
Explain the bleaching effect of chlorine —What proportion of hydrogen
to chlorine is necessary for the formation of hydrochloric acid gas ?—State
the prominent chemical and physical characters of sulphur.—State those
of carbon.—State those of iodine.—Give the derivations of the names of
some of the elements,
NUMERICAL AND PHYSICAL MATTERS OF SPE-
CIAL IMPORTANCE IN ELEMENTARY
CHEMISTRY.
The Metric System of Weights and Measures (the word
metric is from the Greek pérpor, metron, measure) which is
now in common use in most of the countries of Europe and
elsewhere, presents several advantages over the older systems.
The two chief advantages of the metric system are, that cer-
tain of the units are related to one another in an exceeding]
simple and practical manner; and that the system is a deci-
mal one throughout, and is thus in complete harmony with
the universal mode of counting.
The metric system of weights and measures is founded on
the metre. Fig. 12 represents a pocket folding measure the
tenth partof a metre in length, divided into 10 centimetres,
and each centimetre into 10 millimetres,
The units of the system, with their multiples and submul-
tiples, are as follows:—
Length.—The Unit of Length is the Metre, derived from
THE METRIC SYSTEM. 41
the measurement of the Quadrant of a Meridian of the Earth.
(Practically it is the length of certain carefully preserved
bars of metal, from which copies have been taken.)
Surface.—The Unit of Surface is the Are, which is the
square of Ten Metres.
The decimetre.
Capacity.—The Unit of Capacity is the Livre. It was
originally intended that the Litre should be exactly one
Cubic Decimetre, but the Standard Litre although very
nearly in conformity with this intention is not i 80.
(1 Litre = 1.00016 Cubie Decimetre.) In the U. 8. Phar-
macopeeia the Cubic Centimetre is understood to be identical
with the millilitre, or thousandth part of a litre,
_ Mass.—The Unit of Mase is the Grammer,’ which is the
mass of that quantity of distilled water, at its maximum den- ~
sity pomt (4°C.) which occupies the space of the one-
thousandth part of a Litre (1 Millilitre),
TABLE.
Note,—Multiples are denoted by the Greek words ‘‘Deka,”
Ten, ‘‘Hecto,” Hundred, ‘‘Kilo,’’ Thousand.
Subdivisions by the Latin words, ‘‘Deci,’’ One-tenth,
*Centi,’’ One-hundreth, ‘‘Milli,’’ One-thousandth,
Length. Surface. Capacity. Weight.
Kilo-metre es Kilo-litre Kilo-gramme
Heeto-metre Hectare Hecto-litre Hecto-cramme
10 Deca-melre ~~ > Deca-litre Deca-gramme
1 f Units) METRE ARE LITRE GRAMME
Deci-metre Deci-litre Deci-cramme
On Centi-metre Centiare Centi-litre Centi-gramme
-001 Milli-metre aie) 8 Milli-litre Milli-gramme
When the Metric method is exclusively adopted, these Units
and Table, comprising the entire System of Weights and Measures,
represent all that will be essential to be learned in lieu of the
numerous and complicated Tables hitherto in use. Adopting the
style of elementary books on arithmetic, the table may be ex-
panded thus:—
| Di ecinae gramme is sometimes, unfortunalely written gram, which
too closely resembles the word grain.
42 NUMERICAL AND PHYSICAL MATTERS.
10 milligrammes make 1 centigramme; 10 centigrammes make
1 decigramme; 10 decigrammes make 1 gramme; 10 grammes
make | decagramme, or dekagramme; 10 decagrammes make 1
hectogramme; 10 hectogrammes make | kilogramme; 10 milli-
litres make 1 centilitre. etc.; 10 millimetres make | centimetre, etc.
Abbreviations, —Metre = m ; decimetre = dm ; centimetre = em;
millimetre = mm; kilometre= 4m. Square metre = mn? ; cubic
metre—=ne®; and so on. Litre=/; decilitre=ad/ etc, Kilo-
gramme = ky ; decagramme = dég ; gramme = g; decigramme =
dg; centigramme = cg; and milligramme = mg.
The following approximate equivalents of metrical units should
be committed to memory:
1 Metre =3 feet 3 inches and 3 eights.
1 Are = square whose side is 11 yards.
1 Litre = 2642 U. 8. liquid gallons
1 Gramme = 15) grains,
The Kilometre is eqnal to 1100 yards,
The Hectare = 24 acres nearly.
The Metric Ton of 1000 Kilogrammes = 19 ewt, 2 qrs. 20 lbs, 10 oz,
The Kilogramme =2 Ibs. 3} oz. nearly.
A litre of water at 39° F. (8.9° C.) weighs 15,432 grains; at
50° F. (10° C,), 15,429 grains; at 60° PF. (15.5° C.), 15,418
grains; at 70°F, (21.1°C.), 15,403 grains; and at 80°F, (26.7°C.),
15,383 grains (Pile).
Decimal Coinage.—In most countries where the metric system
of weights and measures is employed, a decimal coinage is also
adopted, This, conjoined with the ordinary decimal method of
enumerating, which fortunately is in universal use simplifies
calculations of all kinds,
WEIGHTS AND MEASURES OF THE METRIC SYSTEM.
WEIGHTS.
1 Milligramme = the thousandth part of one grm.,or 0.001 grm.
| Centigramme =the hundreth ‘ . Gil
1 Decigramme = the tenth af os | «4
1 Gramme = weight of one millilitre of dis-
tilled water at 4° C, (39.2° F.)
1 Dekagramme — ten grammes 10.0 *
1 Hectogramme = one hundred grammes 1OO,0
1 Kilogramme = one thousand grammes 1000.0 (1 kilo).
MEASURES OF CAPACITY.
1 Millilitre —the volume at 4° C. of 1 gramme of water.
1 Centilitre ie Ke 10 ee rT
1 Decilitre ‘4 ke 100 7 ee
1 Litre : as as LOOo és ee
THE METRIC SYSTEM. 43
MEASURES OF LENGTH.
vi 1 Millimetre = the thousandth part of one metre or 0,001 metre
|
a, *
1 Centimetre =the hundreth ‘ ee eon us
1 Decimetre =the tenth hy + 0.1 ¥
1 Metre = vs a 0.0 “
RELATIONS BETWEEN THE VARIOUS UNITS OF WEIGHTS AND
MEASURES IN USE.
39,3700 inches
00.914402 metre
0), 264170467 liquid gallon
5.755434 litres
29.5737 millilitres
2.20462 pounds or 15482.35689 grains
458.5924277 grammes
28,3495 grammes
1 Metre
1 Yard
1 Liguid gall
1 Liguid gallon
1 Fiuidounce
1 Kilogramme
1 Pound
1 Ounce
1 Apothecaries’ fe
ounce j
Hd ad
31. 103848 grammes
= 64.7989 milligrammes
COMPARISONS OF WEIGHT AND VOLUME AT MAXIMUM DENSITY,
IN VACUO,
1 Litre of water weighs 1 Kilogramme
1 Gallon of water weighs 3785.434 grammes or 58418. 1444
grains,
1 Fluidounce of water weighs 29.5737 grammes or 456.392
grains,
1 Apothecaries’ Ounce of water measures 31,10348 millilitres
or cubic centimetres, or 504.829 minims.
QUESTIONS AND EXERCISES.
Mention some advantages of the metric (decimal) system of weights
and measnres.—What is the chief unit of the metric system ?—Mention
the names of the metric units of surface, capacity, and mass, and state
how they are derived from the unit of length.—How are multiples of
metric units indicated )—State the designation of submultiplesof metric
onitse.—How many metres are there in a kilometre ?—How many milli-
métres ina metre?—How many grammes in 5 kilogrammes ?—How thany
in 13) grammes?—In 1898 centigrammes how many
mes ?—In a metre measure 5 centimetres wide and 1 contimetre
thick, how many cubic centimetres ?—How many litres are contained
i acubic metre of any liquid ?—State the equivalent of the metre in
Teet and inches.—How many square yards in an are?—How many
fuldounices in a litre ?—How many ounces in a kilogramme ?
Measurement of Temperature. Fahrenheit and Centigrade Ther-
mometer Seales (Fig, 13).—The measurement of temperature is
Carried out by aid of the thermometer,’ the construction of which
>»
|
. al * From Mpuy, therme, heal, and wérpov, metron, measure.
44 NUMERICAL AND PHYSICAL MATTERS
is described in the Section on Quantitative Measurements, The
thermometers employed in the United States are practically always
graduated in accordance with either the Fahrenheit or the Centi-
Fic. 13 grade scale. On the Centigrade (C,) scale
. the freezing-point of water is marked zero,
and the boiling-point 100; on the Fahrenheit
(F,) scale the zero is placed 32 degrees below
the freezing-point of water, and the boiling-
point is 212. Conversions of expressions of
temperatures in degrees F. into the corres-
ponding expressions in degrees C., and con-
versions in the reverse direction, can be made
by applying the following rules :—
1. F. toC, Substract 32, multiply the re-
mainder by 5, divide the product by 9.
Exrample:—68° F. Find the corresponding
id
68-32 = 36; 36% 5 = 180+9=— 20. 68° F.
corresponds to 20° O,
2. C, to F. Multiply by 9, divide the pro-
duct by 5, add $2,
Example:—52° C. Find the corresponding
Fahrenheit, Centigrade.
Thermometric scales, of
52 9 = 468; 468+ 5 = 93.6; 93.6 + 82=1
52 °C. corresponds to 125.6° F.
The following is an easily remembered rule for converting from
°C. to °F. :—
Double the number of degrees C., substract from the result its
tenth part, add 32,
Thus, applying the rule to the example immediately preceding:
52 2= 104; 104-10,4 = 93.6; 93.6 + 382 = 125.6.
52 °C. corresponds, as above, to 125.6 °F.
Care must be taken in dealing with expressions of temperature
having the — sign; that is, with expressions representing tempera-
tures below the zero points of the respective scales.
Example-— -4 °F, Find the corresponding °C,
—4-32=>-36; -—36 « 5=—-—180+ 9 =—20,
-4 °F, corresponds to — 20 °C.
Measurement of Atmoapheric Pressure. The Barometer.—The
analysis of gasea and yapors involves determinations of the varying
pressure of the atmosphere as indicated by the barometer (from
Bdpoc, baros, weight, and yérpov, mefron, measure).
The ordinary mercurial barometer is a glass tube 38 or 34 inches
long, closed at one end, which has been filled with mereury and
inverted in a small cistern or cup of mercury (Fig. 14). The
ATMOSPHERIC PRESSURE. 45
greater part of the mereury remains in the tube, owing to the
pressure of the atmosphere on the exposed surface of the liquid,
the average height of the column being nearly 30inches. In the
ej Soa form of the instrament, the wheel barometer, the cistern
is formed by a recurvature of the tube (Fig. 15); on the exposed
surface of the mercury a float is
Fie. 14. placed, from which a thread passes Fia, 15,
*~. over a pulley and moves an index ia
/ whenever the column of mercury rises
\
4
%
* or falls, The glass tube and con-
tained column of mercury are alto-
gether enclosed, the index alone
being visible In the form first
described the upper end of the glass
tube and mercurial column are ex-
posed, and the height of the mer-
cury is ascertained by direct obser-
vation.
The aneroid barometer (from 4, a,
without, and wypic, nérox, fluid) con-
sists of a small, shallow, vacuous
metal drum, the sides of which ap-
proach cach other when an increase
of atmospheric pressure occurs, their
elasticity enabling them to recede
toward their former position on a
decrease of pressure. This motion
is so multiplied and altered, in direc-
. tion by levers, etc., as to act on a
Barometer. hand traversing a plate on which Shwnen shad
are marked numbers corresponding
with those showing the height of the mercurial column of the
ordinary burometer by which the aneroid was adjusted. The
Bourdon barometer (from the name of the inventor) is a modified
aneroid, containing in the place of the round metal box a flattened
vacuous tnbe of metal bent nearly toa circle. These barometers
are also used for measuring the pressure in steam-boilers, ete,
Under the name of pressure-gauges they are sold to indicate
pressures of as much as 500 pounds per square inch or higher.
Aneroid barometers, on account of their portability (they can be
made of 1 to 2 inches in diameter and less than an inch thick),
are handy companions for ascertuining the heights of hills,
mountains, and other elevations,
-
wesc as aaa” *
Se a ae oe
= 7
===
=_
*%
<—_m ree ee =
—
== a i
"
\
!
\
'
\
‘
'
‘
'
'
'
)
4
]
i
i
4
a
'
\
(
1}
4
'
t )
'
‘
L
‘
46 NUMERICAL AND PHYSICAL MATTERS.
QUESTIONS AND EXERCISES,
Give rules for the conversion of degrees C. into degrees F., and of
degrees F. into dogrees C.—Name the degree C. equivalent to 0° F.—
What degree C. is represented by - 4° F, ?—Mention the degree F.
indicated by 20° C.—Convert 100° F, into degrees C.—How are varia-
tions in atmospheric pressure determined {—Explain the construction
and mode of action of barometers.—In what respect does a wheel-
harometer differ from an instrument in which the readings are taken
from the top ef the column of mereury !)—Describe the construction
and mode of action of an aneroid barometer.
Relation of the Volume of a Gas to Pressure and to Temperature,
The volume occupied by any given quan tity of a gas varies (a)
with variations in the pressure to which it is subjected; and (6)
with variations in its temperature. The amount of the variation
in volume for any given change in either of these conditions is
practically independent of the nature of the gas, since (within
moderate ranges of pressure and of temperature) it is approx-
imately the same for all gases, unless these are near their
liquefying points, The observed variations take place approxi-
mately in accordance with the following laws:—
Boyles Law.—When the temperature of a quantity of gas is
kept constant, the volume which the gas occupies varies inversely
as the pressure. When the original pressure is doubled, the volume
is diminished to one-half ; when it is trebled, the volume is
diminished to one-third ; when it is halved, the volume is doubled,
and soon, The pressu re under which a gas is measured is expressed
in millimetres of mercury—that is, by the height in millimetres
of a column of mercury capable of conten balancing the pressure
exerted by the gas.
Charles's Law.’—When the pressure under which a quantity of
gus is measured is kept constant, the volume which the gas occupies
varies directly as the ‘‘absolute’’ temperature. The absolute
temperature is obtained by adding 273 to the observed temperature
of the gis in degrees Centigrade. Suppose that a quantity of gas
occupies 273 Ce. at 0° C., then the volumes which it is found to
occupy at the temperatures in Column I. of the following table
are those given in Column IIT, Columns IT. and IIL. show how the
volume yaries directly as the absolute temperature,
[. IT. I.
Temperature Absolute ote lee Volume in
in °C. (=t.). (=
1
Ps
LO
ol)
—I1
— 10
— $0
t Also occasionally called “Gay Lussac’s Law."
DENSITY. 47
This table illustrates another way in which Charles’s law may
be stated, viz., that the volume of a gas is increased or diminished
by =f; (= 0.00366) of its volume at 0° C. for each degree Centi-
grade that the temperature of the gas is raised or lowered.
Standard Temperature and Pressure.—The temperature of 0 C.
and the pressure of 760 Mm. are termed standard temperature and
itendard pressure respectively,
It is frequently necessary to calculate, in accordance with the
foregoing laws, what the volume of a quantity of gas would become
under new conditions of pressure and of temperature, when its
volume under stated conditions (original conditions) is known,
The calculation (which is often termed ‘‘correction for pressure and
temperuture’’) can be made in all such cases in accordance with
the following fairly obvious rule:—
Taking the known volume,
(1) Multiply by the original pressure, and divide by the new
pressure; and
(2) Multiply by the new absolute temperature, and divide by
the original absolute temperature.
Example:—A quantity of hydrogen occupies 260 Ce, at 27 C.,
and 750 Mm. Find its volume at 0° C. and 780 Mm.
We have here:—Known volume = 260 Cc. ; Original Pressure =
750 Mm.; New Pressure = 780 Mm.; Original Absolute Tempera-
ture = 273 4- 27° = 300°; New Absolute Temperature = 273 +
0° = 273°.
Proceeding as indicated by the rule given above, we get:
750 275
sou Xx — > — = 227.5 Co,
780 30)
Density —By the density of a substance we understand the
number of units of mass of the substance which occupy a unit
of space. The gramme and the millilitre are adopted as unit of
mass and unit of space respectively, and the density of a substance
is then represented by the number of grammes of that substance
which oceupy a millilitre. At 4° Centigrade one gramme of water
iesa millilitre, hence at this temperature the density of water
is = 1 in terms of the nbove units.
Relative Densities ar Specific Gravities of Liquids and of Solids. —
Relative densities (or specific gravities) are the densities of other
substances a4 compared with that of some substance which is
chosen as standard. Water at 4° C. (with density assumed = 1)
would be a theoretically perfect standard for the comparison of
the relative densities of other liquids and of solids. At 4° Centi-
grade water ia at ita maximum density point; that is to say, any
given en of water occupies at this temperature a smaller
volume than it does at any temperature above or below 4°C, The
- Mimbers representing the relative densities of solids and of liquids,
48 NUMERICAL AND PHYSICAL MATTERS.
in terms of the units and standard referred to above, would thus
show how many times heavier or lighter the respective substances
are, bulk for bulk, than water at 4° C.; or, what is the same thing,
how many grammes of the respective substances occupy the same
space as one gramme of water at 4° C, (i.e, 1 millilitre),
Relative Densities of Cases. —The relative densities (or specific
gravities) of other guses are usually compared with the density of
hydrogen, the lightest known gas, which is arbitrarily chosen as
standard, with density =1. (Formerly air was the standard
adopted with density=1.) In order to be in a position to compare
the density ofany given gas with that of the standard, itis necessary
to determine the masses of equal volumes of both gases, under
the same conditions of pressure and of temperature (sce p, 46, and
the Section on Quantitative Measurements), The numbers repre-
senting the relative densities of gases show how many times heavier
the respective gases are, bulk for bulk, than hydrogen under the
sume conditions of pressure and of temperature, or, what is the
sume thing, how many grammes of the respective guses occupy,
under the same conditions of pressure and of temperature, the
same space as one gramme of, hydrogen (i.e, 11.1 litres).
Vapor Density. —This term is applied to the relative density (or
specific gravity) of the vapor in the case of any substance which
is liquid or solid at ordinary temperatures but which is capable of
being converted into the state of vapor, without undergoing decom-
position, by a sufficient rise of temperature. Vapor densities are
thus strictly comparable with the relative densities of gases. (See
the Section on Quantitative Measurements. )
QUESTIONS AND EXERCISES,
Define Boyle’s law.—What does the volume of a litre of hydrogen
at ordinary atmospheric pressure become when the pressare is doubled,
halved, quadrupled !—Mention to ways in which the regularity known
as Charles’s law may be stated.—How is the number which represents
the ahsolute temperatare obtained ?—Define standard temperature and
presstire.—What is the rule for “correcting’’ the volume of a gas for
change in temperature and pressure ?—What do you understand by the
terms density, relative density, vapor density ?
The student ia recommended to read the following paragraphs on
the General Principles af Chemical Philosophy carefully onee or
twice, then to study (experimentally, if possible) the succeeding pages,
returning fo and reading over the General Principles Jrom time to
time until they are thoroughly comprehended,
' Note, however, that the standard temperature adopted in practice
for comparing specific gravities is not 4° C,, bul 25° C. (77° F,), (See
the Section on Quantitative Measurements. )
CHEMICAL AND PHYSICAL CHANGES, 49
THE GENERAL PRINCIPLES OF CHEMICAL
PHILOSOPHY,
The Science of Chemistry treats of a particular class of changes
that matter undergoes, These changes result in the formation of
new substances—that is, of substances which are different in com-
position and properties from the materials out of which they have
been produced—and they are commonly called chemical changes.
Such changes may be the result of natural agencies only, as in
the growth of plants and animals in a wholly natural state, and in
the transformations that the inanimate materials of which the
earth is composed undergo owing to climatic and other influences ;
or they may be directed and, so far, controlled by human agency,
as, for example, in the processes carried out in the chemical labora-
tory or manufactory.
Chemical and Physical Changes. —Many well-marked, or typical,
cases of chemical change are easily recognized as such. Some-
times, however, it is difficult, and occasionally it is not possible,
to recognize whether a particular change really is a chemical
change, or whether it belongs to the class of phenomena called
physical changes. The existence of any uncertainty arises from
the difficulty in proving conclusively whether a new substance has
been produced or not, together with the fact that it is not an alto-
gether easy matter to define strictly what constitutes the formation
of a new substance. Familiar examples of physical changes are
furnished by the transformations of solids into the liquid state (as
of ice into water) or of liquids into the state of vapor (as of water
into steam) without any change in the composition of the sub-
stances. In typical cases, the occurrence of chemical change may
usually be recognized by the accompanying phenomena character-
istic of such change. Two of the most important of these phe-
nomena are;—
lL. The disappearance of the properties of the substance or sul-
dances which take part in the change, and the formation of a new
rubstance or of new enbatances possessing other properties,
A mixture of free oxygen und hydrogen is still a gas; water, «
themical compound of oxygen and hydrogen, is a liquid; here is
great alteration in properties. Iodine is only slightly seluble in
water, forming a brown-colored solution, and iron is insoluble ;
tut when iodine and iron are chemical/y combined, the product is
very soluble in water, forming a light-green solution which is
utterly unlike iron or iodine in any one of its properties, and in
which the eye can detect neither iodine nor iron, Tartaric acid
and sodium carbonate, mixed together in presence of water, give
rise to other and wholly different chemical compounds, the original
substances having interacted and formed fresh combinations.
4
50 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY,
Sand, sugar, and butter, rubbed together, form a mere mixture,
from which water would extract the sugar, and ether dissolve out
the butter, leaving the sand. These examples illustrate how
chemical action is distinguished, namely, by producing an entire
change of properties in the resulting substances,
2. The giving out, or the absorption of heat, during the change.
When coal or a candle burns in the air, the carbon present in
the combustible material unites with the oxygen of the atmos-
phere, with the evolution or giving out of heat, Sulphur, phos-
phorus, certain metals such as magnesium and zinc, as well as
many other substances, likewise burn in the air, with the evolu-
tion of heat, These instances of combustion are all examples of
chemical action, and are readily distinguishable as such.
Besides the two important phenomenn noted nbove as character-
istic of chemical changes, it is further to be observed that chem-
ical combination takes place between the substances which enter
into reaction (interact) in certain definite proportions by weight
only, and not simply in any proportions in which they may, by
chance or by intention, be mixed together. The quite general
recularities that have been observed in connection with this matter
are discussed below under the Laws of Chemical Combination.
Elements and Compounds.—In modern chemistry the term ele-
ment is applied to any substance which has not. been shown to be
compound—that is, to possess a composite nature. The word is
strictly reserved for those substances which the chemist is neither
able to break up into two or more simpler substances, nor to pro-
duce by the union of two or more simpler substances, The ele-
ments are the simplest forms of matter known, The term com-
pound is applied to all substances the composite nature of which
can be proved. The proof may consist in breaking up the com-
pound into two or more simpler substances by some method of
decomposition ; or it may consist in building up the compound from
two or more simpler substances, by causing these to combine—that
is, by affecting its synthesis,'
Up to the present, about 70 elements have been discovered, and
more or less minutely examined and described. Of these ele-
ments, about 40 are either of practical importance themselves, or
they enter into the composition of compounds which are of prac-
tical importance, All of the enormous number of chemical com-
pounds that have been prepared and examined are combinations
of two or more of the known elements.
Chemieal Affinity is the name applied to that tendency exhibited
by certain clementary and compound substances to enter into
fresh combinations with one another so as to form new compounds,
The name is sometimes applied also to the tendency of substances
1 The word synthesis is (rom wieteos, sunthesis, a putting together; anal-
yeis, a term often used to designate the reverse operation of decomposi-
tion, 18 from areaAve, analud, I resolve,
LAW OF CHEMICAL COMBINATION. 51
to remain combined after combination, with the formation of new
compounds, has taken place.
Laws of Chemical Combination.—Chemical combination takes
place between definite quantities of substances. The more impor-
tant quantitative relations are expressed by the following laws:—
The Law of Constant Proportions states that the same chemical
arene is always composed of the same elements, and~That
th ements are present in the compound in the same relative
proportions by weight. Thus any pure specimen of common galt
if found on analysis to contain the elements sodium and chlorine
only, and these are associated with each other in proportions of
22.88 parts by weight of sodium to 35,18 parts by weight of
chlorine, Similarly any pure specimen of sulphuric acid contains
hydrogen, sulphur, and oxygen, associated with one another in the
proportions of 2 parts by weight of hydrogen to 31.83 of sulphur
and 65.52 of oxygen. To the general statement of the law of
constant proportions, it may be added that the mass of (or quan-
tity of matter contained in) any compound substance is equal to
the sum of the masses of its constituents.
The Law of Multiple Proportions,—The same elements are some-
times capable of wniting with each other in more than one propor-
tion by weight. The law of multiple proportions states that, when
this is the case, the several quantities of one of the elements
which combine to form two or more compounds with any given
quantity of the other element, stand in simple multitude relations
either to each other or to some common submultiple. Thus in
the two oxides of carbon there are contained :
|
Parts by weight Parts by weight of
of Carbon. | Oxygen.
Carbonic oxide... 16
Carbonicanhydride. . . : 32
_ OOOO
and in the two oxides of phosphorus there are contained :
Parts by weight of Parts by weight of
Phosphorus, Oxyren,
Phosphorous anhydride . 62 | 48 (=16«38)
Phesphoricanhydride .. 62 | 80 ( <16«5)
—
The Law of Gaseous Volumes states that when gases combine
with one another, the volumes which unite stand in a simple rela-
tion to each other and also to the volume of the product when
52 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
this is 4 gaseous substance. The simple relations of the volumes
of the combining gases to each other and to the volume of the
product in a few cases illustrative of this law, are exhibited in the
following table;—
Volumes of Combining gases. Volume of product.
VWydrogen 1, Chlorine 1 Hydrochloric acid 2
Hydrogen 2, Oxygen 1 Water vapor 2
Carbonic oxide 2, Oxygen 1 | Carbonic anhydride 2
Carbonic oxide 1, eI, Chlorine 1 Phosgen 1
N. B.—In each of the foregoing cases it is necessary to assume
that the volumes of the combining gases and of the product are
measured under the same conditions of pressure and of tempera-
ture. (See p. 46.)
The Atomie Theory.—Certain theoretical conceptions which
have since developed into what is now called the Atomic Theory,
were first employed in chemistry by John Dalton, a Manchester
chemist, in explanation of the regularity which has already been
mentioned as the Law of Multiple Proportions (p. 51). The most
important assumptions of this theory are stated in the following
paragraphs.
Matter of all kinds is assumed to be composed of extremely
minute, indivisible particles. These particles have been called
afoms, Single atoms are so small as to be entirely beyond our
powers of observation, even with the aid of the most powerful
magnifying instruments. It is assumed that each element consists
of atoms of one kind only, the kind, however, being different for
every element, Every compound, on the other hand, is assumed
to contain atoms of at least two different kinds—that is, atoms of
at least two different elements—combined together chemically.
Estimates have been made as to the probable shape, size, and
mass of atoms, At best, these must be regarded as approxi-
mations only. Experimental evidence points to the atoms of
different elements possessing very different weights, The absolute
mass is not known in the case of any atom, but the ratio to each
other of the weights of the atoms of different elements can he
determined with accuracy. A series of numbers which represent
the relative weights of the different kinds of atoms has nccordingly
been drawn up. These numbers are relative atomic weights, and
are asm rule simply called atomic weights. They will be discussed
further on,
The aggregates of atoma which are produced when two or more
unlike atoms combine together to form the smallest particles of a
AVOGADRO'’S HYPOTHESIS. 53
compound substance, are called molecu/es,' The most simply
constituted molecule of a compound substance conceivable must
necessarily consist of at least two unlike atoms, The molecules
of carbonic oxide are believed to possess this simple constitution,
and to consist each of one atom of carbon and one atom of oxygen.
The next simplest conceivable constitution for the molecule of a
compound is that it should consist of three atoms. In this case ,
there are two possibilities: —
1, All three atoms may be different ; or
2. Two atoms may be of one kind and one of another. |
The molecules of hydrocyanic acid are regarded as illustrating
the first of these possibilities, and as consisting each of one atom
of hydrogen, one of carbon, and one of nitrogen. The molecules
of carbonic anhydride are regarded as illustrating the second, and
as consisting each of one atom of carbon and two of oxygen,
The molecules of many substances are supposed to present much
greater complexity than these,
If we now compare carbonic oxide and carbonic anhydride in
light of the atomic theory, we perecive the character of the ex-
planation afforded by the theory for the observed facts concerning
the quantitative relations to each other of the elements which form
the two compounds (p. 51). Carbonic anhydride contains, for a
given weight of carbon, exactly twice as much oxygen as carbonic
oxide does. According to the atomic theory, this is because a
molecule of carbonic anhydride contains for one atom of carbon,
two atoms of oxygen, while a molecule of carbonic oxide contains
for one atom of carbon, only one atom of oxygen.
Avogadro's Hypothesis. —When the facts which find expression
in the Law of Gaseous Volumes—referring, as they do, to the
combination of gases in simple rational proportions by volume to
form products whose volumes are simply related to those of the
which combine (p. 51)—are considered in connection with
idea of combination in simple atomic proportions according to
Dalton’s atomic theory, it becomes evident that there must be a
simple relation between the volumes which gases occupy and the
numbers of molecules present in these volumes. The nature of
the relation is expressed by the Hypothesis of Avogadro, which is
usnally stated as follows:—
Equal volumes of all gases, under the same conditions of presaure
and of temperature contain the same number of molecules,
Tn order to bring this very simple hypothesis into harmony with
the observed facts, in all cases of combination of gases with each
other, it is necessary to make the further assumption that even in
mentary prises, hydrogen, oxygen, nitrogen, and chlorine,
4 1 word molecule is alao applicd, as will appear later, to aggregates
& of two or more bike wtoms. A numberof elementary gases
“S00 yapor are supposed to be made op of particles consisting of such
groups of like atoms,
54 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY,
the particles do not consist of single atoms, but of pairs of /ike
atoms associnted together to form molecules, In illustration of
this matter, the case of the combination of hydrogen with chlorine
furnishes a ‘good example. One volume of hydrogen combines,
as we have seen (p. 52), with one volume of chlorine to form two
volumes of hydrochloric acid gas.’ The volume of the product
. is here double that of either of the constituent gases, there-
fore, according to Avogadro’s Hypothesis, it contains twice as
many molecules as either of those volumes, But every molecule
of the resulting hydrochloric acid gas contains both hy drogen and
chlorine, and, as there are twice as many molecules of it (each
containing hy drogen and chlorine) as there were of the original hy-
drogen or of the original chlorine, each molecule of the two latter
gases must have undergone division into two parts, and must
therefore have consisted originally of not fewer than two atoms.
There is evidence from another source that the molecules of the
elementary gases do not consist of more than two atoms (p. 58).
Molecular Weights.—If, as Avogadro’s Hypothesis assumes,
equal volumes of all gases contain, under like conditions, the same
number of molecules, then the differences in the weights of equal
volumes of the various gases (as observed in making determinations
of their relative densities) can only be accounted for by differences
in the weights of the respective molecules of which the different
gases consist, Accordingly the determination of the weights of
equal volumes of different gases (under like conditions) should
furnish numbers which stand to each other in the ratios of the
weights of the molecules of the respective gases. But this is the
determination which is actually made in ascertaining the relative
densities of gases (p. 48); hence the numbers representing the
relative densities of gases lead directly to the relative weights of
the molecules of the gases.
As already stated, hydrogen is adopted as standard, with density
= 1, for the comparison of the relative densities of other gases
(p. 48). For the comparison of the relative molecular weights
of gases hydrogen is also adopted as standard, but with molecular
weight = 2. Hence, since the relative molecular weight is in all
pases proportional to the relative density, the relative molecular
weight of any gas is expressed by a number which is double that
which expresses its relative density. Thus we have:
Relative Density. Relative Molecular
Weight.
Hydrogen F : ; 1 2,
Oxygen . ; ; - 15, 88 O1.76
Carbonic anhydride . ‘ 21.855 43.07
Water vapor : ; 8,94 17,88
and soon. The numbers designated relative molecular weights
above are, asa rule, simply called Molecular Weighta,
‘All measured under like conditions of pressure and of tempernture.
ATOMIC WEIGHTS. 5)
There are many substances of which the molecular weights are
unknown, because they cannot be obtained in the gaseous state,
and because certain other known methods of molecular weight
determination cannot be applied to them,
(rramme Molecule.—For chemical purposes it is often convenient
to deal with definite quantities of substances in grammes (but of
coursé other definite weights could be employed), these quantities
bel the molecular weights of the substances. When
hich expresses the molecular weight of any substance
is considered as representing that same number of grammes, this
quantity is called the ‘molecular weight in grammes’’ of the
poem or, more shortly, the gramme molecule, This is an
important quantity with respect to each substance, (Compare
pp. — and 59.) The gramme molecule of hydrogen weighs two
Alowie Weights,—If, in accordance with the atomic theory,
are aggregates of atoms, the weight of any given mole-
cule must be made up of the separate weights of the atoms which
compose it, and must, therefore, be equal to the sum of these
separate ea ag Hence, if itis possible to ascertain by any
means the kinds of atoms, and the number of each kind, which
fo to constitute the molecules of any compound it should like-
wise be possible to ascertain the relative weights of the atoms of
each kind from the relative molecular weights of the compounds
into whose composition they enter. It has, as a matter of fact,
been found possible to obtain a great deal of information with
to these matters. The means by which this information
ned may be stated as follows.
1. By making use of the ordinary methods of chemical analysis,
the kinds of atoms present in a compound can be determined ;
that is, the ppeence of the particular elements of which it is com-
posed can be recognized, and the absence of others can be proved.
she preset of quantitative analysis, the quantity of each
resent in a given compound can be determined,
a When the results of quantitative analyses are so tabulated as
to show the weight of each element which is present in those
of compound substances which have already been
i as their mme molecules, it is found that the
molecules of different compounds containing one element
common, contain quantities of that element which are related
t each other ina very simple manner. The nature of this simple
relation is exhibited in the subjoined tables. In each of these
eee menee given in Column Il. represents the weights in
of the substances named in Column [., which occupy, in
gaseous state, and under like conditions of pressure and of
perature, the same volume as two grammes of hydrogen. The
mS given in Columns II. und IV. show the composition,
ht, of the quantity of each substance which is set down in
56 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
l, HYDROGEN, AND HYDROGEN COMPOUNDS,
Names of substances and weights of The weights stated in Column II., of
the guseous state and under like con- ||
grammes of hydrogen. weights, in grammes, of—
I. IL. IT. IV.
Names. Weights. Hydrogen. (ther Elements.
Hydrochloric acid. . . 36.15 Chlorine . . . $5.18
Hydrobromie acid .. 80.36 Bromine . . . 79.36
Hydrogen .....-. 2.00
Oxy 4 * 15.88
Water... 17.88
Hydrogen sulphide ~~. SESS Sulp * » Vane
Nitrogen . . . 13.93
Ammonia. . 16.93
Hydrogen phosphide . . oa77 Phosphorus . . 30.77
Carbon . . . « IL91
Marsh gas . . .« 1691
Olefiant gus... .. . 27.82 Carbon . - 23.82
(Carbon . . . 23.82
Ethyl aleohol. . . . . 45.7 Oxygen . . . . 15,88
10 (Carbon . . . . 47.64
SANeF ces ts te | TBD
(Oxygen... . 16.88
Il. OXYGEN, AND Oxyarn ComMPOUNDS,
I. IIT. IV.
le ee ll
oy
I.
Naines. Weights. Oxygen, Other Elements.
OS ee 17.88 15,88 Base en
Carbonic oxide. . . . 27.79 15.88 ‘arbon . . . . 7191
Oxygen . . 4 31.76 31.76
Carbonic anhydride: . 48.67 S170 Carbon . . . . VL
Sulphurons anhydride 68.59 31.76 Sulphur . . . 81.83
Sulphuric anhydride . 79.47 47.04 Sep snes + « BL88
‘opi 5 Ae d= RK f Hy rogen . « + 1.00
Nitric acid . . . . . © 69.57 17.64 \ Nitrogen * * 49°09
Ill. Carron Compounns,.
I. If. ITT, TV.
Names. Weights. Carbon, Other Flements.
Carbonic oxide ...... =. £47.79 11.91 15.88
MATE. ORS. ws eee te 15.91 11.9] 4.10
ee eee 6,00
Mihyl alcohol. 1: Se ree ae 45,70 25,82 21,88
PROBAMR vei teu es. 4888 35.79 8.00)
en a oy Be 57.64 47.64 10,00
IV. NIrroGex, AND Nrrrogen ComMPpouNDs,
L ~ ay ITT, TV,
Naties. Welghts. Nitrogen. Other Elements.
Ammonia . . «se sua 16,03 13.93 3.00
Nitric oxide . . Nerdre s Se 13.93 15,88
Nitric acid a ee 62.47 13.93 48,64
Nitrogen , Teeter OF Bi} 27 Sh
Nitrous oxide aa) os 133 . 2 7. °7 RG 1A.88
=i
(yYanowen . . oe feet ems 51.8 97 86 95.82
The simple relation to which reference has been made, is
ATOMIC WEIGHTS. 57
observed when the numbers which fall into Colamn III, in each
table are considered, Thus the quantity of each substance which
in the state of gus occupies the same volume, under the sume con-
ditions of pressure and of temperature, as 2 grammes of hydrogen
(Column II.), does not in any case contain a smaller quantity of
n than | gramme, of oxygen than 15.88 grammes, of car-
bon than 11.91 grammes, or of nitrogen than 13.93 grammes.
Further, if the quantity of any compound noted in Column II.
contains more than 1 gramme of hydrogen, it does not contain
less than 2 grammes; if more than 2 grammes, not less than 8
grammes, and soon, Similarly in the case of oxygen compounds,
if the quantity noted in Column IL. contains more than 15.88
grammes of oxygen, it does not contain less than 31.76 grammes;
if more than 31.76 grammes, then not less than 47.64 grammes,
and so on. Regularity of the same simple kind is also observed
with respect to the carbon and nitrogen compounds. The lists of
compounds given here are intended to be illustrative only, and
not exhaustive; since each table might have been greatly
extended, and additional tables might have been given, embracing
compounds of many other elements, when the same kind of regu-
larity would have appeared throughout. In the case of each
element, therefore, there appears in Column IIL. a minimum
namber, and all the numbers in this column for one and the same
element are either this minimum number or multiples of it. It
is concluded from the uniformity observed in this respect that the
minimum number so obtained for each element represents (rela-
tively to hydrogen assumed = 1) the smallest proportion by
put & in which that particular element enters into combination—
that this minimum number is, in short, the atomic weight of the
element, The atomic theory offers a sufficient explanation of the
observed facta. Yn the oxygen compounds, for example, the
molecular weights of these compounds are made up of the weights
of the atoms of the other elements present in the molecule besides
oxygen, and of 1, 2, 3, etc. times the weight of one atom of
From this we conclude that the various molecules con-
tain 1, : 2, 3, ete. atoms of oxygen, It is clear that if a molecule
contin any oxygen at all, it must contain not less than one atom
_of this clement ; if it contains more than one atom, it cannot con-
tain fewer than two atoms, and so op. Exactly similar consider-
ations may be applied to the compounds of other elements.
An examination of the facts contained in the tables, and of the
inclusions drawn from them, justifies the view that there are in
1 atom of oxygen and 2 of hydrogen
a
dd ia ] ‘ carbon
re D Wh nttenean
~~ - rm nitrogen
Ci rbon 4“ ‘
58 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
In the tables réferring to the compounds of hydrogen, oxygen,
and nitrogen, the elements themselves huve also been included.
Tt will be noticed that the figures for them in Column IL. of the
respective tables are not the minimum numbers which have been
arrived at as their atomic weights, but are double these numbers,
From this it is concluded that their molecules must each consist
of two, and of not more than two, atoms.
Law of Dulong and Petit, —This law states that the product of
the atomic weight and the specific heat of solid elements is a con-
stant number. This constant is called the atomic heat, und hence
the law may also be stated thus :—
The atomic heats of all solid elements are equal.
The law does not hold quite accurately, the atomic heats of
solid elements being found to differ from one another to some
extent. They nearly all approximate moderately closely, how-
ever, to the number 6.4, A few examples are given below :—
Atomic Weight *
Element. Atomic Weight, Specific Heat. Specific Heat
(~ Atomic Hewt),
29
112
O03
wi O54
Mercury. .... . LOS, 032
The determination of the specific heat is sometimes made in
order to confirm the atomic weight of an element, since the con-
stunt 6.4 + specific heat should give a quotient approximating to
the atomic weight.
Chemical Notation.—A system of notation has been adopted for
the purpose of shortly and concisely expressing the chief facts
concerning chemical actions. This system is bused upon the
fucts, and the theories deduced from these facts, which have been
outlined in the preceding pages. The essential fentures of the
system are explained in the following paragraphs :
1. Symbols,—For the purposes of the system, each element has
had a symbol assigned to it. This symbol is usually the first
letter, sometimes the first and a succeeding letter, of the English
or of the Latin name for the element, Thus, H is the symbol
for hydrogen, Fe (Ferrum) the symbol for iron, and so on. A
list of the names of the elements, with their symbols and their
atomic weights will be found at top of page 59,
For a complete list of the elements, with their symbols and
atomic weights, see the Appendix.
The symbol for each element is employed to represent :-—
a. The name of the element.
6, An atom of the element.
e. A definite weight, in grammes, of the element. This weight
is the number representing the atomic weight of the
CHEMICAL NOTATION. 59
The Chief Elements mentioned in the United States Pharmacopeia,
with their Symone and A tomic Weights.
|
8 -!
Element. | Lo | | Atomic Element. Sym Weight.
_—_— Sooo ~—— |
Aluminium. .. .| Al 26.9 |! Lead (Plumbum).| Pb | 205.35
Antimony (Stibium) sb 119.3 ||Lithium.... . Li 6.98
rsenic ..... | As 74.4 ||Magnesium. ...| Mg| 24.18
Barium ..... Ba | 136.4 || Manganese. . . Mn| 54.6
Bismuth... . . Bi | 206.9 || Mercury(Hydrar gy-
Boron. ..... B 10.9 rum) ..... Hg | 198.5
Bromine. ... .| Br | 79.3 || Nitrogen. . .. .| N 13.93
Calcium. ... .{| Ca 39.8 ||Oxygen ..... O 15.88
Carbon . ... ./ C 11.91 || Phosphorus . . . | P 30.77
Cerium ..... | Ce | 139.2 |/Platinum ... .f i 193.3
Chlorine . 35.18 || Potassium ( Kalium ), K 38.86
.| Cl
Chromium . . - Cr 51.7 ||Silver (Argentum) ; Ag | 107.12
|
|
|
|
rE 1.00 || Tin (Stannum) . Sn | 118.1
Fe |
r (Cuprum) Cu, 63.1 ||Sodium (Natrium) i Na | 22.88
Geld Aurum) . Au; 195.7 ||Sulphur .... . S 31.83
Hydrogen . He
Iodine. . . 1. . 125.90 || Zinc. . . . -. mn | 64.9
Iron (Ferrum) . . 655
element, taken as grammes; thus the symbol for hydrogen
represents 1 gramme of hydrogen, because the atomic
weight of hydrogen is 1; the symbol for iron, 55.5 gram-
mes of iron, because the atomic weight of iron is 55,5;
and so on.
2. Formule.—Symbols are employed in writing formule. A
chemical formula usually consists of two or more symbols written
side by side, as CO, which represents carbonic oxide.
When two or more atoms of the same kind are to be represented
in a formula, this is done by writing a small figure to the right
of and on a somewhat lower level than, the symbol. The figure
indicates the number of atoms to be represented. Thus, the
formula CH, represents a compound containing one atom of earbon
and four of hydrogen. A small figure similarly placed after a
portion of a formula which is enclosed within brackets, multiplies ~~
everything that is so enclosed. Thus, Ba(NQO,), indicates a sub-
stance in which an atom of barium is combined with twice the
group NOs.
A figure placed in front of a formula refers to the whole
formula, and shows how many times the quantity represented by
the formula is to be taken. Thus, 3CH, stands for three times
the quantity of marsh gas represented by CH
The formula for a substance represents in all cases:—
a. The kinds of atoms of which the substance consists.
b. The ratio of the number of atoms of each kind.
((
..
60 CHEMICAL NOTATION.
e. A definite weight, in grammes, of the substance. This
weight is the sum of the atomic weights of the atoms rep-
resented by the formula, taken as grammes. It is called
the formula weight,
In the case of gases, and of solids and liquids which can be
converted into the gaseous state without decomposition, the
formula further represents:—
d. The quantity of the substance which has already been
referred to as the gramme molecule (p. 55),
e. A definite volume of the substance in the gaseous state,
This volume is, in the case of each substance, when under
the same conditions of pressure and of temperature, the
same as that occupied by two grammes (the gramme mole-
cule) of hydrogen. It is called the gramme molecule
volume, When numerical expression is given to it, the
conditions must be stated, since it varies with variations
of pressure und of temperature. Under standard con-
ditions of pressure and of temperature (i.¢., 760 Mm, and
0° C,, see p. 47), it measures 22,2 litres.
8. Deduction of the Formula for a Compound from its Compo-
sition percent,—The results of quantitative chemical analyses of
compounds are usually expressed in parts by weight percent. of
each constituent. From these results an empirica/ formula can
be deduced. An empirical formula merely expresses the ratio of
the number of atoms of each kind in the smallest whole numbers.
A molecular formula, on the other hand, expresses the number
of atoms of each kind which a molecule is assumed to contain.
The rule for the deduction of the simplest formula, is to divide
the quantity percent. of each element by the atomic weight of
that element, The quotients stand to each other in the ratio of
the numbers of atoms present in the compound. Thus, the gas
ethylene has the following composition percent. :—
C, 85.62; H, 14.38.
Dividing by the ec ve atomic weights, we get:—
85.62 + 11. 01 = 7.19, and 14.388 + 1 = 14,38,
But 7.19: 14.38: : hence the carbon and hydrogen atoms
are present in the eg of 1:2, and the empirical formula is
CH.,,
The molecular weight of ethylene, however, is found by
experiment to be 27.82, while the formula CH, corresponds to
the molecular weight 15.91; hence the molec ular formula must
be (CH,),, that is, C,H,,
N.B,—From the composition percent. alone, the empirical formula
ean be deduced. The molecular formula can only be obtained when
the molecular weight wa alao known,
GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY. 61
4. Caleulation of the Composition percent, of a Substance from its
Formula,—First add up the formula weight of the substance.
From this and the separate weights of the constituents the com-
ibe percent. is obtained by simple proportion. Thus, to find
the composition percent. of carbonic anhydride, CO,:—
C= 11.91
O, = 31.76 (15,88 > 2)
43,67 = Formula weight.
Here 43.67 parts by weight contain 11.91 of carbon.
| 11.91 x 100
.*» LOO contain 43.67 — == 27.37.
Again, 43.67 parts by weight contain 31.76 of oxygen.
31.76 % 100
. LOO contain 13.67. == 72,73.
The composition percent. therefore, is :—
C = 27,27; O = 72.78.
5. Equations.—Formule are employed in writing chemical
equations. These equations represent the changes which occur
during chemical actions. Formule representing the quantity of
each substance which enters into action are placed on one side,
and formule representing the quantity of each product are placed
on the other side of the sign of equality (=). Between the
various formul# on each side, signs of addition (-}-) are placed.
These signs are not used in the same sense as in a mathematical
equation; and a chemical equation is really only an equation in
#o far that all the materials represented on the one side must be
accounted for in some form on the other side.
The chemical change which occurs when zine is placed in
dilute sulphuric acid is represented by the equation:—
%m + HS0, = H, + ZnSO,
This equation, besides showing the nature of the rearrangement of
atoms which takes place, indicates the proportions by weight in
which the substances interact and the proportions of the products,
since each symbol and formula has its own quantitative signifi-
»
cation, It further indicates the volume of hydrogen which can be
obtained from the weights of materials represented, since the form-
tla for a gas represents not only a definite weight, but also a definite
yolume (ata given pressure and temperature) of the gas. Thus, 64.9
sammes of zinc and 97.35 grammes of sulphuric acid yield 2
r of hydrogen and 160.25 grammes of zine sulphate, The
mes of hydrogen occupy 22.2 litres at O°O" and 760 Mm.
m such equations, calculations are readily made of the
ntities of substances hy weight or by volume obtainable from
>
7 72 =
given quantities of materials,
a _
; »
62 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
Instead of writing formal equations to represent chemical
actions, the student will often find it helpful and instructive to
draw diagrams of « kind which show equally well the original
form in which the various elements are brought into reaction, and
the destination of the different atoms. For example, instead of
writing the equation given above, the liberation of hydrogen by
the interaction of zine and dilute sulphuric acid can be sufficiently
represented for most purposes by writing the formule for zinc and
sulphuric acid either in the same line or one above the other, to
show what substances interact, and then drawing a line to enclose
the SO, of the sulphuric acid formula along with the Zn, and
leaving the H, of the sulphuric acid formula outside, thus:—
H, SO,
If the interaction of zine with hydrochloric acid is to be repre-
sented, the diagram can be constructed thus:—
The construction of such diagrams is particularly useful in aiding
the student to obtain an insight into numerous complicated inter-
actions, Other examples will be given further on.
Equivalents ( Valency).—Those (quantities of ifferent elements
which are capable of playing the 3tme part fit chemical combina-
tion, are said to be equivalent to each other. For comparison of
the equivalent weights of different elements, it is convenient to
adopt a standard, and the standard chosen is | part by weight of
hydrogen, The equivalent weights—or shortly, the equivalents—
of other elements are capable of taking the place in combination
of 1 part by weight of hydrogen (and frequently, moreever, of
combining with the same weights of other elements that 1 part by
weight of hydrogen combines with). Thus, in potassium chloride,
KCl, 38.86 parts by weight of potassium take the place of the 1
part by weight of hydrogen contained in hydrochloric acid, ACI,
hence the equivalent of potassium is 48.86. In calcium sulphate,
CaSO,, 39.8 parts by weight of calcium take the place of the 2
parts hy weight of hydrogen contained in sulphuric acid, H,50,,
o«
hence the equivalent of calcium is = =19.9. In bismuth
nitrate, Bi(NO,),, 206.9 parts by weight of bismuth take the
place of 8 parte by weight of hydrogen in three molecules of nitric
] . ¢
acid, 8HNO,, hence the equivalent is = = 68.966, and so on,
EQUIVALENTS. 63
The number expressing the equivalent weight is thus sometimes
the same as the atomic weight, sometimes it is one-half the atomic
‘sometimes one-third, and so on. In other words, an atom
The number representing the valency of an element may be
ascertained by observing the number of hydrogen atoms which it
is capable of replacing, or with which it is capable of combining ;
also, by observing, for sani the number of atoms of chlorine
with which it is capable of combining—each atom of chlorine
regarded as of the same valency as hydrogen, because each
atom of chlorine combines with one atom of hydrogen.
For es potassium (K), calcium (Ca), bismuth (Bi), and
carbon (C), are regarded as univalent, bivalent, trivalent and quad-
rivalent, respectively, because they form chlorine compounds
represented by the formule KCI, CaCl,, BiCl,, CCl,. In the
ease of carbon, CH, is also known °
With respect to the terms equivalent and valency, it is to be
noted that they are applicable to radicals' as well as to atoms.
sch eget hate, CaSO,, the mdical SO, is equivalent
calcium nitrate, Ca(NO,),, or to Cl, in calcium
since it is capable of combining with the same
thing, wi one atom of calcium, 80, is « bivalent radical,
nth NO, and Cl are univalent.
sometimes convenient to indicate the valency of a metallic
placing after it an appropriate number of dots, thus:
ularly the valency of an acid radical may be indi-
iute number of dashes, thus: PO,’’’.
Sond Salts.—In order to give the ‘student some
n these classes of chemical substances, and so to
hin =a 1¢ better to understand the use of the words base,
#, and the frequent references to these substances in the
ng portions of this Manual, it is desirable,
the discussion of the general principles of
some general statements regarding these im-
are two principal classes of compounds which
is very often used in chemistry to designate u group
s common to a number of compounds, and is capable of
I from one compound to another without itself breaking
eae saw
64 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
behave as bases, and possess in a more or less marked degree the
properties of these substances, as described further on. These
two classes embrace :—
1. The basic oxides and hydroxides of the metals. Examples—
Calcium oxide (quicklime) CaO; calcium hydroxide (slaked
lime) ep ie aluminium hydroxide AI(OH),; ferric _ ,
oxide Fe,O,, ete. ————
2, Ammonia, N H,, and the substituted ammonias (such as
methylamine, NH,CH,; dimethylamine; NH(CH,), ;
aniline, NH,O.H,, ete.); also a large number of allied sub-
stances, including the natural alkaloids (such as morphine
©,,H,,NO,, H,O; strychnine C,,H,,N,O,, ete.
There are grounds for supposing that all substances which
exhibit the characters of bases are hydroxides, and that those
compounds belonging to the above two classes which are not
hydroxides to begin with, must interact with water, so as to yield
hydroxides before their capacity to behave as bases is developed.
Thus, it is probable that quicklime is not itself a base, but that
the actual base is slaked lime (calcium hydroxide), which is
formed by the interaction of quicklime with water:—
CaO + H,O = Ca(OH), ;
and that ammonia only attains basic properties when it has inter-
acted with water to form ammonium hydroxide—
NH, + H,O = NH,OH.
Properties of Bases.—Those bases which dissolve easily in water
yield solutions possessing an alkaline reaction, that is, their solu-
tions exhibit the property possessed by solutions of the a/kalies
(potassium hydroxide, KOH, and sodium hydroxide, NaOH,
which are themselves basic hydroxides, see pages 72 and 86) of
turning red litmus paper blue, of browning yellow turmeric
paper, ete. Solutions of some of the most easily soluble bases,
such as potassium and sodium hydroxides, possess an unpleasant
taste, resembling that of soapy water. (As a matter of fact, the
taste of soapy water is chiefly due to the presence of one or other
of these hydroxides in smal] quantity.)
Bases interact with acids to form sa/fs, This statement is true
generally, but it requires qualification in so far that there are
some bases which (usually on account of their insoluble character)
are not acted upon by certain acids. When bases interact with
acida, the formation of salts is accompanied by the formation of
water:—
Cu(OH), + 2HCL = CaCl, + 20,0;
2A(OH), + 3H,8O, = Al,(S80,), + 6H,0;
NH,OH + HCl = NHC) + H,0;
BASES, ACIDS, SALTS. 65
Aciils, —Three important classes of acids may be distinguished.
These classes do not exhibit many prominent differences in char-
acter, although they differ considerably in their general chemical
relations. The three classes are :— /
1. Acids which may be regarded as derived from acid oxides —
or acid anhydrides, by the action of water. Thus sul-
a anhydride when treated with water yields sulphuric
ac) —
SO, + H,O = H,SO,
(The majority of the more important acid anhydrides are,
as the student will learn later, oxides of non-metallic
Sesnbats.) All the acids belonging to this class contain
oxygen.
2, Acids which do not contain any oxygen in their compo-
sition, The best examples are the halogen acids—hydro-
chlorie acid, HCl; hydrobromie acid, HBr ; hydriodic
acid, HI ; and hydrofluoric acid, HF,
a A large number of organic acids, wll containing carbon,
hydrogen, and oxygen, either : along with, or without other
elements. Examples—Oxalic acid, H,0,0,; ; aectic acid,
H,©,0,; benzoic acid, H,C,O,; chloracetic acid, H,C,0 Cl,
etc,
Properties of Acids.—The majority of acids dissolve readily in
water. The aqueous solutions in most cases possess the acid
reaction, that is, they redden blue litmus paper. They also
possess a characteristic sour taste, as in the familiar cases of
tartaric acid (the acid of unripe grapes), acetic acid (the acid
present in vinegar), etc.
All acits contain hydrogen as an essential constituent. This
hydrogen is replaceable, in some cases wholly, in some only
partially, by metals, or by groups of atoms (radicals) which play
the part of metals. The substances produced by such replace-
ment are called salts, They are formed, as has already been
stated, by the interaction of bases and acids, with the simul-
tuneous production of water.
Salt—Salts are compounds which may all be regarded as
made up of metal, or of a radical which plays the part of metal
—such metal or radical forming the metallic or basic radieal—
united to an atom, or group of atoms, which constitutes the acid
radical, Whe metallic radical of the salt takes the place of the
lrydrogen of the acid, or of a part of it: the acid radical of the
salt is common both to the salt and to the acid from which it is
derived. In un sense, the acids are themselves salts. They
resemble salts in several particulars, and they are fre-
quently called hydrogen werlta,
Salts are — paduced in various other ways, as well as by the
‘interaction bases and acids. A common instance of this is
66 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
seen in the formation of salts by the interaction of metals and
acids. Thus the best way to prepare silver nitrate is to treat
silver with nitric acid.
The following classes of salts are distinguished :—
Neutral Salts,— These salts when dissolved in water yield
solutions which show neither the acid nor the alkaline reaction,
Examples of neutral salts—Sodium chloride, NaCl; potassium
~ sulphate, K,SO,; ete.
Normal Salts, —This name is applied to salts which are formed
when the whole of the replaceable hydrogen of an acid is replaced
by a metal. Normal salts are frequently neutral also, but they
are not necessarily so. Examples of normal salts—Potassium
sulphate, K,SO, ; sodium carbonate, Na,CO,.
Acid Salts,—Salts which contain some of the replaceable hy-
drogen of the original acid unreplaced by metal, are called acid
salts. They are intermediate in composition between the acid
and the normal salt. Thus potassium hydrogen sulphate, KHSO,
(an acid salt), is intermediate between sulphuric acid, H,SO,,
and normal potassium sulphate, K,SO,. Acid salts possess the
acid character, in so far that they still contain hydrogen of the
original acid, which is replaceable by metal to form a normal salt,
They do not, however, necessarily show the acid reaction with litmus,
Basic Salts,—Salts which are intermediate in composition between
basic oxide or bydroxide and normal salt, are called basic salts,
Thus bismuth oxychloride, BiOC! (a basic salt), is intermediate
hetween basic bismuth oxide, Bi,O,, and normal bismuth chloride,
BiCl,. Basic salts possess the basic character, in so far that
they still contain oxygen of the basie oxide, or hydroxy! (OH) of
the basic hydroxide, which is replaceable by an acid radical to
form a normal salt. A large number of basic salts are insoluble
in water, and cannot therefore show any reaction with litmus.
Basicity of Acids, and Acidity of Bases,— Acids are called
monobasic, dibasic, tribasic, ete., according as they contain in
their molecules. one, two, three, etc., hydrogen atoms displaceable
by metals. Polybasic acids contain several displaceable hydrogen
atoms. Bases are called mono-acid, di-acid, tri-acid, ete., accord-
ing as the acid radical from one, two, three, etc., molecules of a
monobasic acid enters into the composition of the normal salts
derived from them,
Equations illustrating basicity of acids :—
HNO, +- KOH =KNO, + H,O
H,80, + 2KOH = K,80, + 2H,O0
H,PO, +- 3KOH = K,PO, + 3H,0
Equations illustrating acidity of bases :—
KOH + HCl= KC! + H,O
Ca(OH), + 2HC) = CaCl, 4+- 2H,0
Bi(OH), + SHCl = BiCl, -} 8H,0
ELECTROLYSIS. 67
Electrolysis. —W hen a current of electricity is passed through
a dilute solution of sulphuric acid, by introducing into the
solution electrodes (which may consist conveniently of strips of
platinum foil) connected with the wires leading from a sufficiently
powerful battery, hydrogen is given off at the electrode connected
with the negative pole of the battery, and oxygen at that con-
nected with the positive pole. These gases are given off in the
proportions in which they combine to form water, and the exper-
iment at first sight appears to be, and is sometimes simply called,
the electrolysis (that is, the decomposition by a current of elec-
tricity) of water. The sulphuric acid, however, although its
quantity remains the same at the end of the experiment as it was
at the beginning, obviously plays an important part in the process,
because in its absence scarcely amy current passes, and corres-
pondingly little water is decomposed, The nature of the chem-
ical change which takes place may be represented as, in the first
place, the liberation, from the acid, of hydrogen at the one
electrode and of the acid radical—the group 8O,—at the other.
But the acid radical (SO,) is unknown as a separate substance,
and is probably incapable of existence as such; hence, at the
moment of its liberation, it interacts with water of the solution,
taking its hydrogen to form sulphuric acid again, and liberating
its oxygen. These changes may be illustrated diagrammatically
as follows :—
(a) As the first result of electrolysis, H,SO, yields :—
At the tive electrode. At the itive electrode.
“fin mts
(6) Further change : ;
| [S0,] and H,0* give H,SO, and O!
gee oh the final result of the change is that water mole-
ws are, this indirect means, decomposed into hydrogen
and oxygen, * while the sulphuric acid remains in undiminished
quantity at the end of the experiment.
A case nearly analogous with the preceding one is that of the
electrolysis of a solution of sodium sulphate. In this case also,
hydrogen and oxygen are given off in the proportions in which
' Single atoms of hydrogen and of oxygen liberated in this way ut the
‘tive trodes unite with each other in pairs to form molecules
of guseous hydrogen, Hy, and oxygen, ©» (or the oxygen atoms may to
some extent unite in groups of three to form molecnles of ozone, Oa;
[see Index].
* The group [FQ] may also be regarded as interacting with two water
les to form HeS04 and two (OH) groups, which latter are then
supposed to Dliterect, with the formation of water and oxygen:
[50d + HOH m= ESO, + lox ; and On. = H,O+ O
68 GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
they are present in water. It may be represented that the sodium
sulphate is first separated into sodium and the acid radical of the
sulphates, Na,SO, yielding :
At the negative ¢lectrode. At the positive electrode.
“Wa Na | PRO,
But in this instance the sodium as well as the acid radical enters
into a new reaction with water of the solution and the following
further changes oceur :
2Na and 2H,0 give [SO,] and H,0 give
2NaOH and H,, HS0, and O,
In light of the foregoing mode of representing the electrolysis
of sodium sulphate, it would appear that sodium hydroxide is
produced at the negative pole in addition to the hydrogen; and
that sulphuric acid is produced at the positive pole in addition to
the oxygen. This is indeed found to be the case, and may easily
he demonstrated by testing the liquid in the immediate neighbor-
hood of the two electrodes, by means of litmus papers, during
the passage of the current, Whilst the sodiam sulphate solution
is itself neutral, the liquid at the negative pole is found to be
alkaline, and that at the positive pole is found to be acid. It is
to be noted, moreover, that the quantity of sodium hydroxide
formed at the negative electrode is exactly the quantity required to
interact with the whole of the sulphuric acid formed at the posi-
tive electrode, to form sodium sulphate again (neutral solution)
in accordance with the equation,
2NaOH + H,SO, = Na,SO, + 2H,0
s0 that when the solution is thoroughly mixed up sodium sul-
phate is present in it in undiminished quantity.
Other salts in aqueous solution (or in the fused state if they
stand fusion without undergoing decomposition) can also be elec-
trolyzed. The metal of the salt, or that which plays the part of
metal, is separated at the negative electrode, and the acid radical
ut the positive electrode, Substances which are capable of decom-
position by electrolysis are called eleetro/ytes. When the first
products of the electrolysis are capable of existence in the con-
ditions under which they are produced, then these are the
products obtained. Secondary changes are, however, of frequent
oecurrence, as in the foregoing illustrations.
In regard to their electrolysis, the acids (hydrogen salts) behave
in & manner exactly analogous with the behavior of other salts.
The positive electrode is often called the anode, and the nega-
tive electrode the cathode (ava, ana, upward; xara, hate, down-
ward; ddoc, hodos, way). Metals and hydrogen are set free at the
cathode, and acid radicals and oxygen at the anode.
It has been found that the quantity of an electrolyte which
ELECTROLYSIS. 69
undergoes decomposition by electrolysis is directly proportional to
the amount of current passed through it. Further, it has been
found that the quantities of hydrogen, and the quantities of
oxygen liberated in a given time from dilute solutions of sulphuric
acid, of sodium sulphate, and of potassium sulphate, when the
current is passed simultaneously through all three solutions, are
the same for each solution, Similarly the quantities of copper
separated from two or more different cupric salts under like con-
ditions are identical: and the same kind of regularity holds good
for other metals and acid radicals.
In recent years electrolytic methods have been extensively
introduced for the technical production of chemical compounds,
for the separation of metals, etc. References to the preparation
of a number of substances by these methods, are made in various
places in this Manual. See, for example, under potassium chlor-
ate, sodium by hydroxide, iodoform, aluminium, sodium, ete.
Oxygen and hydrogen, when liberated from combination in
immediate contact with substances with which they are capable
of interacting to yield products of omdation and reduction (reduc-
tion=deoxidation or removal of oxygen), are found to be mach
more active towards these substances than they are if prepared in
separate vessels and subsequently brought into contact with them,
The special activity of such nascent (i.¢., newly formed) oxygen
and hydrogen, has been attributed to the action of atoms of these
elements, which enter into other reactions without combining in
irs to form oxygen and hydrogen molecules, Various electro-
and other oxidations, reductions, etc., are apparently due to
the action of nascent oxygen, nascent hydrogen, nascent chlorine,
ete. Jn a number of cases in later parts of the Manual, where
equations are given in which the action of nascent hydrogen, ete.,
is represented, the atomic symbols, H, 0, ete,, are used instead of
the molecular formule, H,, O,, ete,
The student is recommended to read the foregoing paragraphs on
the (General principles of Chemical Philosophy carefully onee or
hice, then to atudy (experimentally, if possible) the following pages,
returning to and reading over the General Principles from time to
lime, until they are thoroughly comprehended,
QUESTIONS AND EXERCISES.
What do you tnderstand by chemical changes?—Give examples of
chemical and physical changes.—Mention some of the chief phenomena
whieh ficcompany typicn! cases of chemical change,—Whal is the dif-
between an element and a compound ?—What do you understand
by the term “chemical affinity’'’—Name the chief laws of chemical
—Siate the law of constant proportions. —Stute the law of
o rtions.—State the law of guseous volumes,—Give an out-
line of the ie theory, explaining what is understood by the terms
70 THE ELEMENTS AND THEIR COMPOUNDS.
“atom” and “molecule."—What is Avogadro's hypothesis ?—Explain
why hydrogen molecules are assumed (0 consist of two hydrogen atoms
each.—What relation exists between the relative densities and the mole-
chlar weights of gases?—What is the “gramme molecule” ?—Explain
how Avogalro’s hypothesis may be applied in the fixing of atomic
weights.—State the law of Dulong and Petit, and explain how it may be
of service in fixing atomic weights.—Enumerate the functions of a chem-
ical symbo! and of a chemical formula.—Write equations representing
the formation of hydrogen by the interaction of zine with hydrochloric
acid and with sulphuric acid.—Mention the characters of bases and acids,
and deseribe the general nature of the interaction of bases and acids in
forming salts.—What are neutral salts, normal salts, acid salts, basie
salts’—Give examples.—Define electrolysis, electrolyte, eleetrode.—
What do you understand by “ nascent’’ hydrogen ?—Name some impor-
tant substances which are now prepared on the manufacturing seale by
electrolytic methods,
THE ELEMENTS AND THEIR COMPOUNDS,
Having thus obtained a general idea of the nature of some of
the non-metallic elements which have special interest for the med-
ical and pharmaceutical student, and of the fundamental princi-
ples of chemistry, we may pass on to consider in detail the rela-
tions of the elements, both non-metallic and metallic, to each
other. The elements themselves, in the free condition, are sel-
dom used in medicine, being nearly always in combination—
bound together by the force of chemical affinity; in this combined
condition, therefore, they must be studied, inorganic combinations
first, organic afterwards. Most compounds met within the mineral]
kingdom may be regarded as containing two parts or radicals :—
the one usually metallic; the other commonly a non-metallic,
simple or complex, acid radical. In the following pages the
metallic radicals will be considered first, the acid radicals after-
ward. Each radical will be studied from two points of view,
the synthetical and the analytical; that is to say, the properties of
an element on which the preparations of its compounds depends
will be illustrated by discriptions of actual experiments, and thus
a knowledge of the principles of chemistry and of their applica-
tions to medicine and pharmacy be acquired; then the reactions
by which the element is detected,-though combined by other sub-
stances, will be performed, and so the student will be instructed
in qualitative analysis, Synthetical and analytical reactions are,
in truth, frequently identical, the object with which they are per-
formed giving them synthetical interest on the one hand,, or
analytical interest on the other. ‘
A good knowledge of chemistry may be acquired synthetically
by preparing considerable quantities of the salts of the different
metals, or analytically by going through a course of pure quali-
tative analysis. But the former plan demands a larger expendi-
ture of time than most students have to spare, while under the
Note.—As a general rule, throughout this Manual, paragraphs
describing experiments to be performed are distinguished from
containing matter merely to be read, by being printed
in somewhat larger type.
THE METALLIC RADICALS.
POTASSIUM: K. Atomic weight, 38,86,
Occurrence, ete.—The chief sources of the potassium salts are
the chloride found at Stassfurt, in Prussia, combined with mag-
nesium chloride in the mineral Carnallite, KCI,MgCl,,6H,O and
ium sulphate in Kainite, KCl »MgSo,, 3H,0; the
nitrate found in soils, especially in warm countries; and the com-
pounds of potassium existing in plants. The potassium salts
anaes ants are converted chiefly into carbonate when the
parts are burnt to ashes, If the ashes be lixivi-
uted with water, and the solution evaporated to dryness, the
residue when fused constitutes crude potashes, The residue cal-
reg on the hearth of a reverberatory furnace till white, gives
termed pearlash, which is impure potassium car-
Large quantities of potassium carbonate are thus pro-
in North America and Russia, and, latterly, from the
orhaw oct mare, in France. Nearly all other potassium
compounds are made from the native chloride, or from the car-
lee ples has been purified by treating pearlash with its own
of distilled water, filtering, and evaporating the solution
“ancy eran while it is kept briskly agitated, Ex-
ium nitrate, and in cream of tartar
S. P.), which is the more or less purified
seeting ‘salt of the grape vine. Potassium, in the
m of one or other of its compounds, is a constituent of over
fit nical or galenical preparations of the Pharmacopeia.
yaration.—Potassium itself is isolated by distilling a mixture
| Re jum carbonate and charcoal at a very high temperature,
Chane method (see Sodium). It rapidly undergoes
1 inthe air, hence is usually kept below the surface of
itha which protects it from oxidation. It crystal-
72 THE METALLIC RADICALS.
Potassium carbonate (Potassii Carbonas, U. 8. P.), is a white
erystalline or granular powder, insolu ble in ‘alcohol but very
soluble in water yielding a solution which is alkaline and caustic
to the taste. It rapidly liquefies in the air through absorption of
moisture. It loses all water at a red heat.
Potassium Hydroxide. Caustic Potash,
Experiment 1.—Boil together for a few minutes, in a basin,
ten to twenty grains of potassium carbonate, K,CO,, and a
like quantity of calcium hydroxide (slaked lime ), Ca(OH),
with a small quantity of water. Set the mixture aside in a
closed yessel till all solid matter has subsided,
The clear liquid is a solution of potassium hydroxide or caustic
potash, KOH. Made of a prescribed concentration (about 5 per-
cent.) it forms Liquor Potassit Hydroxidi, U, 8. P.
The mixture is known to have been boiled long enough when
a little of the clear liquid, poured into a test-tube and warmed,
gives no effervescence on the addition of an acid (sulphuric,
hydrochloric, or acetic)—a test the mode of action of which will
be explained hereafter.
Solid Caustic Potash.—Solution of caustic potash evaporated to
dryness in a silver or clean iron vessel, and the residue fused and
poured into moulds, constitutes caustic potash (Potassii Hydroxi-
dum U.8. P). Tt often contains chlorides, detected by means of
silver nitrate; and sulphates, detected by means of a barium
salt; as described subsequently in connection with hydrochloric
and sulphuric acids,
Representing Chemical Changes by means of Equations and Dia-
gqrams.—It is desirable that the student should endeavour to
represent each chemical change that comes under his notice by
means of an equation or diagram. The mode of constructing
such equations and diagrams has been explained already, and the
student is aware that the chief data required for their construction
are the formule of the various substances which enter into and
are produced by the particular changes under consideration,
Thus, solution of potassium carbonate and calcium hydroxide
interact when boiled together to produce calcium carbonate and
potassium hydroxide. It is necessary to know the formule for
all these substances before an equation or diagram can be con-
structed to represent the interaction, The required formul® are
respectively, K,CO,, Ca(OH), CaCO, and KOH, <A few mo-
ments’ reflection should enable the student to perceive that in
order that CaCo, may be built up from Ca(OH), and K,CO,, the
latter of these two must rive up K, while the ‘former must give
up (OH),; and, further, in order that the K, and the (OH), may
be conceived as forming a substance having the formula KOH, it
POTASSIUM. . 73
must be supposed that these materials unite to form two KOH
A diagram representing the change can then be constructed
easily thus :—
ieadecceeeeeuent
4
‘ 7"
4 i
7
*
*
*
*
cee he fe eae err ee
. OH
or an equation written thus ;—
Ca(OH), + K,CO, = CaCO, + 2KOH
The interaction represented by the above diagram and equation
is an instance of that kind of chemical change commonly called
double ition, the two metallic radicals exchanging places.
The name metathesis (werd, meta, beyond, and Aéoic thesis, a
placing) is sometimes given to interactions of this description.
At the same time that the student is constructing these dia-
grams and equations for himself, he will carefully bear in mind
that each formula stands for a definite quantity of the substance
which it represents; and that, by adding up the quantities thus
indicated » Seg formule constituting an equation, he can readily
ascertain the proportions by weight in which the substances
interact and result from interaction.
Sulphurated Potash,
2.—Into a test-tube put a few grains of a
mixture of previously dried potassium carbonate and half its
weight of sulphur. Heat the mixture gradually until it no
ee effervesces, The resulting fused mass poured on a
and quickly bottled is sulphurated potash.
SK.CO,; + 4, = KS,O, + 2K 8, + 3800,
Sulphur Potassium Potassium Carbonle
iT thiosul phate trisulphide anhydride
As met with in pharmacy, this substance is not a single definite
ical compound, but a mixture of several; in short, its
chemical character is well indicated by its vague name, When
‘treeh, and if carefully prepared with dry ingredients, it is of the
volor of liver (whence the old name “iver of sulphur’), and
onsiats, as shown by J. Watts, of the salts mentioned in the
eeoing equation, together with a little undecomposed potas-
cull
(
—-.
oars es = , * * ~* ~ Jt all nS . oe.
and : By rapidly absorbing oxygen from the air, it soon
nes green and yellow, potassium sulphite, K.SO,, and sulphite
+9 mite, with perhaps higher potassium sulphides (KA,
yee i rt y . i.8 - bd
j K, ,, g successively formed, and ultimately a useless mass of
“a dirty white color results, consisting of potassium sulphate and
el
74 THE METALLIC RADICALS,
thiosulphate, with generally some carbonate and free sulphur,
Moreover, if overheated in manufacture, the potassium thiosulphate
is decomposed into sulphate and pentasulphide (4K,5,0, = 3K,50,
+ K,S;). About fifty percent. of the freshly-made preparation
should be soluble in alcohol (90 percent.). It is occasionally
employed in the form of ointment,
The complicated nature of the interactions that take place in
this experiment will probably cause failure in any attempt by the
student to represent these by means of a diagram without the aid
of the printed equation already given. He may therefore content
himself, in this case, by introducing into his note-book a diagram
founded directly on the equation, and on the numbers of mole-
cules there stated.
In preparing large quantities of sulphurated potash, the
test-tube is replaced by an earthenware crucible (possibly
from erux, a cross, for originally a cross was impressed upon
the melting-pot used hy alchemists and goldsmiths: others
derive the word from cruz, an instrument of torture, the
sense here being symbolical ).
Fie, 16.
Crucibles of various forms.
Heating crucibles,—Crucibles of a few ounces capacity may be
heated in an ordinary fire, Larger ones requires furnace. Even
the smaller ones are more conveniently and quickly heated in a
furnace. Half-ounce or one-ounce experimental porcelain crucibles
may be heated in a spirit or gas-flame, the flame of the Bunsen
burner already described being generally the most suitable.
Potassium Acetate.
Experiment 3.—Place twenty grains or so of potassium car-
honate in a small porcelain dish, and saturate (satur, full)
with acetic acid ; that is, add acetie acid as long as efferves-
cence is produced; the resulting liquid 1s a shght acid solu-
tion of potassium acetate. Boil off most of the water in an
open dish (See Figs, 17 and 18), stirring with a glass
POTASSIUM. 75
rod’ to assist the escape of water vapor, and thereby prevent
pga a white salt remains, which fuses on the further
Sei toca. of heat: this is the official potassium
it Acetas U. 8S. P.). Uf fused in an open
Fic. 17. Fra. 18,
y ‘Evaporation Siena and Bid basins,
vessel, the acetate ia liable to become slightly charred and
discolored ; this is prevented by transferring the solid residue
to a test-tube or Pnsk before finally fusing. Potassium
acetate forms a white deliquescent foliaceous satiny mass,
neutral to test-paper, and wholly soluble in alcohol.
K,CO, + 2HC.H,O, = 2KC,H,O, + H,O + CO
. Acetic Potassium Water Carbonic
acid acetate anhydride
ion of formula,—The formula for acetic acid (hyd-
autate) is HC,H,O,, and that for potassium acetate,
0, The univalent group or radical, C,H,O,, is common
> all acetates, A more extended formula for potassium acetate,
nena Sard possible arrangement of the atoms in the molecule,
af the reaction, —The nature of the above operation is
indicated by an equation; it (and succeeding reactions) may be
expresed in the student's note-book asa diagram, and, if possible,
without the aid of the above equation,
Note.—The foregoing reaction has a general as well as
‘itterest. [t represents one of the commonest methods of
salts, namely, the decomposition of a carbonate by inter-
Talore an acid. Curbonates added to acetic acid yield
_to nitric acid nitrates, to sulphuric acid su Iphates.
illustrations of this general process occur in pharmacy.
eo
ee srod is usually purchased in longths of 5 or 6 feet. These may be
ala
he » into co aveniient pieces of from 6 to 12 inches long (see p. 21), sharp ends
Bt mnded off by holding the extremities in a flame for a few minutes,
76 THE METALLIC RADICALS.
Evaporation of water from a liquid is best conducted in wide
shallow vessels rather than in narrow deep ones, as the steam can
thus quickly diffuse into the air and rapidly be conveyed away;
hence a small round-bottomed basin, heated as shown in Fig. 17,
is far more suitable than a test-tube for such operations. On the
manufacturing scale, iron, or iron lined with enamel, or semi- *
porcelain, copper, tinned copper, or solid tin pans are used. Up
to 12 or 18 inches diameter, porcelain dishes may be employed,
Small dishes may be supported by retort stands (Fig. 17), larger
by cylinders (Fig. 18), to which the dish is, if less in diameter
than the cylinder, adapted by such flat rings or diaphragms as are
shown in the figure on page 75.
Potassium Bicarbonate. Potassium Hydrogen Carbonate.
Experiment 4.— Make a concentrated solution of potassium
carbonate by heating in a test-tube a mixture of several
grains of the salt with rather less than an equal weight of
water. Through the cool solution pass carbonic anhydride,
slowly but continuously; after a time a white crystalline pre-
cipitate of potassium hydrogen carbonate, or potassium bicar-
bonate, KHCO, (Potassii Bicarbonas, U. S. P.), will he
formed,
K,CO, + H,O + CO, = 2KHCO,
Potassium Water Carbonie Potassium
carbonate anhydride bicarbonate
Generate the carbonic anhydride by adding hydrochloric
acid, diluted with twice its bulk of water, to a few fragments
of marble or other carbonate contained in a test-tube or
small flask, and conduct the gas into the solution of potas-
sium carbonate through a glass tube, bent to a convenient
shape and fitted to the test-tube or flask by means of a cork
in the usual way (see Fig. 10, p.34), though no heat is neces-
sary. The tube may he replenished with marble or acid,
or both, when the evolution of gas is becoming slow. In
working on any larger quantity than «a few grains of the
carbonate, a wide delivery-tube should be employed; or if a
narrow one is employed, the end of it must occasionally be
cleared from any bicarbonate that may have been deposited
in it. A more eeonomical arrangement of the apparatus
employed in this process will be described under the corre-
sponding sodium salt (p, 88).
Deporition of the bicarbonate explained, — Potassium bicarbonate
is to a certain extent soluble in water; but as it is less so than
POTASSIUM. 77
the potassium carbonate, and as a saturated solution of the latter
is employed, the precipitation of a part of the bicarbonate inevi-
tably occurs. In other words, the quantity of water present is
sufficient to dissolve the carbonate, but insufficient to retain in
solution — whole of the bicarbonate formed during the action.
ties. —Prepared on the large scale, potassium bicarbonate
occurs in colorless, non-deliquescent rhombic prisms; it has a
saline, feebly alkaline, non-corrosive taste. Heated to redness,
it loses about 31 percent. of its weight, and is converted into
potassium carbonate, water, and carbonic anhydride.
2KHCO, = K,CO, + H,O + ©O,
————_— —— —S_"
—,-_——"
198, 82 157.27 17,88 43.67
The foregoing equation and accompanying weights (see page 61)
show how potassium bicarbonate loses 31 percent. (17,88 4+- 45,67
in 198,82) when completely decomposed by heat.
Notes on Nomenclature.—The prefix bi- in the name ‘potassium
bicarbonate,”’ serves to recall the fact that for the same quantity
of potassium this salt contains fice as much carbonic acid
rudical as is present in the carbonate, The salt is really a
“notassium and hydrogen carbonate,’’ KHCO,, and is inter-
mediate between potassium carbonate, K,CO,, and hydrogen car-
bonute, or true carbonic acid [H,CO,]. It is ‘potassium acid
carbonate’’ or ‘‘potassium hydrogen carbonate,’’ and is an acid
salt, inasmuch as it contains hydrogen which is displaceable
by metal to form a normal salt, although it is not acid to the
taste.
Salts whose specific names end in the syllable ‘‘ate’’ (carbonate,
anl phate, etc.) are in general conventionally so termed when they
contain the radical (or characteristic group of elements) of an
acid whose name ends in ‘‘ic,”’ and from which acids they have
been or may be formed. Thus the syllable ‘‘afe,’’ in the words
sulphafe, nitrate, acetate, carbonate, etc., indicates that the re-
spective salts contain the radical of an acid whose name ends in
ie, the previous syllables sulph-, acet-, carbon-, indicating what
that acid is—sulphuric, nitric, acetic, or carbonic. Occasionally
a letter or syllable is dropped from or added to a word to render
name more euphonious ; thus the sulphuric radical forms
ra not sulphurates, and the tartaric radical yields fartrates
not tarturates.
: Potassium Citrate.
‘Experiment 5.—Dissolve a few grains or more of | potassium
carbonate i in water, and add citric acid, H\C -H.O., until it no
causes effervescence. The resulting liquid is a solution
of potassium citrate, K,C,H,0O,. Evaporate to dryness, in
78 THE METALLIC RADICALS.
an open dish, cautiously so as to avoid charring; a pulverulent or
granular residue is obtained, which is the official potassium
citrate (Potassit Citras U.S. P.), a white deliquescent powder.
3K,CO, + 2H,C,H,O, = 2K,C,H,O, + 3H,O + 300,
Potassium Citric acid Potussium Water Carbonic
carbonate citrate anhydride
A granulated mixture prepared from potassium citrate, sodium
bicarbonate, and tartaric and citric acid is official (Pofassii Cifras
Eeffervescens).
Citrates. —The citric radical, C,H,O,’’, which with three
atoms of hydrogen forms citric acid, and with three of potassium
forms potassium citrate, is a trivalent group. An extended form-
ula for citric acid is C\H,OH,(COOH),,H,0, that for potassium
citrate being Cy,H,.OH.(COOK),,H,O. The chemistry of citric
acid and other citrates will be described subsequently.
Potassium nitrate, KNO, (Potassii Nitras U. 5. P.), and Potas-
sium sulphate, K,SO, (Potassii Sulphas, U. 8. P.). These salts
could also be made by neutralizing nitric acid, HNO,, and sul-
phuric acid, H,SO,, respectively, with potassium carbonate, Or-
dinarily they are not made in this way—the nitrate occurring, as
already stated, in nature, and the sulphate being obtained as a
by-product in many operations. Both salts will be alluded to
later in connection with nitric acid.
Potassium Tartrate.
Experiment 6.—Place a few grains of potassium carbonate
in a test-tube with a little water, heat to the boiling-point,
and then add acid potassium tartrate, KHC,H,O,, tall there
is no more effervescence; a solution of normal potassium
tartrate, K.C,H,O,, results. Prismatic crystals may be
obtained on concentrating the solution by evaporation and
setting the hot liquid aside. Larger quantities are made in
the same way, 20 parts of potassium hydrogen tartrate and 9
of potassium carbonate (with 50 of water) being about the
proportions necessary for neutrality.
2KHC,H,0, + K,CO, = 2K,C,H,0, + H,O +4 ©O,
Potassium Potassium lotassium Water Carbonic
hydrogen tartrate carbonate tartrate anhydride
Potassium tartrate is slightly deliquescent, and is soluble in about
four parts of boiling water.
Tartrates,—The bivalent radical C,H,0,” is characteristic of all
tartrates ; hence the formula of hydrogen tartrate, or tartaric acid,
is H,C,H,O,; that of potassium tartrate is (K,C,H,O,),,H,0; of
the intermediate salt, acid potassium tartrate (cream of tartar),
KHC,H,O,. If the acid tartrate of one alkali-metal and the car-
POTASSIUM. 79
bonate of another interact, a neutral tartrate results, which con-
tains both metals, as seen in Rochelle salt, KNaC,H,O,,4H,0
Fotewt et Sodii Tartras, U. 5. P.) More extended formule of
salts, indicating constitution, are :—
(CHOH),COOH), ——_[(CHOH),(COOK),],, H,0
Se COOK fOROR LOGON a. COOK, 4H,O
Hydrogen potassium Potassium and sodium tartrate
scision Salts (e.g. KUCH On) that is, salts intermediate in com-
tion between a normal salt (c.g. K,C,H,0,) and an acid (e.g.
Pic. BOO), we frequently met with. All acid radicals, except
are univalent, may be concerned in the formation of
such acid salts. See p. 66.
Potassium Iodide.
Experiment 7.—Into a solution of potassium hydroxide
heated in a test-tube, flask, or eva Rpssneg- bara sees according to
uantity, stir a little solid iodine. The deep color of the iodine
sap entirely. This is due to the formation of the colorless
ium iodide, KI, and potassium iodate, KIO,, which
Semele dimolved in the liquid. Continue the addition of iodine
so long as its color, after a few minutes’ warming and stirring,
disappears. When the whole of the potassium hydroxide in
whe solution has been conyerted into the salts mentioned, the
ight excess of iodine remaining in the liquid will color it,
thus show that this stage of the operation is completed.
6KOH + 31, = SKI + KIO, + 3H,0
Potassium Iodine Potassium Potassium Water
hydroxide jodide jiodate
ion of the iodide from the iodate.—Evaporate the
sol to dryness. If both salts were required, the result-
mixture might be digested in alcohol, which dissolves the
lide but not the iodate. But the iodide only is needed.
iets mix the residue, therefore (reserving a grain or
two for a subsequent experiment), with excess (about a third
of its weight) of charcoal, and gently heat in a test-tube or
crucible until slight deflagration ensues.' The crucible may
: ees a of heating potassium iodate with charcoal, excess
7 of the latter be employed, slight incandescence rather than de -flagration
» meen be largely in excess, the reduction of the potassium
jodide is affected without visible deflagration or even incandes-
tion means violent burning, from fagratus, burt | agro, [
ane 4 , & prefix augmenting the sense of the word to which it may
, Reece Paper thrown into a fire simply burns, nitre causes defla-
the fuel, Detonation (detono) is a similarly constructed word,
: “ne g explosion with violent noise.
80 THE METALLIC RADICALS.
be supported in the flame of a spirit-lamp or Bunsen burner,
or placed in a fire or furnace. The iodide remains unaffected ;
but the iodate loses all its oxygen and is reduced to the state
of iodide.
KIO, + 8 = EF + 3
Potassium Carbon Potassium Carbonic
jodate iodide oxide
Treat the mass with a little water, and filter to separate
excess of charcoal; a solution of pure potassium iodide results,
The latter may be used as a reagent, or it may be evap-
orated to a small bulk and set aside to crystallize,
Properties. —Potassium iodide (Polassii Lodidum, U, 5, P.),
crystallizes in small cubical crystals, very soluble in water, less so
in alcohol. Exposed to air and sunlight, pure potassium iodide
becomes slightly brown, owing, probably, to the combined action
of the oxygen, water vapor, and carbonic anhydride of the atmos-
phere.
The addition of charcoal in the above process is simply to
facilitate the removal of the oxygen from the potassium iodate.
Potassium iodate, KIO,, is analogous in composition to potassium
chlorute, KCIO,, which has already been stated to be more gener-
ally used than any other salt for the actual preparation of oxygen
gas itself, and the removal of its oxygen may be accomplished
by heating the residue without charcoal, In this case the liber-
ated oxygen can be detected by inserting a glowing strip of wood
into the mouth of the test-tube in which the mixture of iodide
and iodate is being heated. The charcoal, however, removes the
oxygen more quickly and at a lower temperature, and thus econ-
omizes both time and heat.
Detection of iodate in iodide.—Potassium iodate remaining as an
impurity in potassium iodide, may be detected by adding to a
solution of the latter salt some weak acid (say, tartaric), shaking,
and then adding starch mucilage; blue ‘‘ iodide of starch” (ace
Starch) is formed if a trace of jiodate be present, but not other-
wise, By the interaction of the added acid and the potassium
iodate, iedic acid, HTO,, is produced; and by interaction of the
added acid and the potassium iodide, hydriodie acid, HI, is pro-
duced; neither of these alone attacks starch, but by their mutual
interaction they yield free iodine, which then forms the blue color
by its action on the starch. This experiment should be tried on
a grain or two of pure iodide and on the impure iodide reserved
from the previous experiment,
Potassium iodide containing iodate would obviously yield free
iodine, which is excessively corrosive, on the salts coming into
contact with the acids of the stomach.
HIO, + S5HI= 8H,0 +- 8I,.
POTASSIUM. 81
Note on Nomenclature.—The final syllable ide in the name
potassium iodide, indicates that the e/ement iodine is combined
with potassium. An iodafe, as already explained, is a salt con-
taining the characteristic radical of odie acid and of all other
jodates. Inorganic salts whose names end in ide, are derived from
acids which do not contain oxygen. Acids with complex radi-
cals, the latter usually containing oxygen, give rise to salts with
names ending in afe (see p. 77) or ite, An inorganic salt whose
name ends in afe contains the radicals of an acid whose name
ends in ie; a salt whose name ends in i¢e contains the radical of
an acid whose name ends in ows ; an inorganic salt whose name
ends in éde contains an element for its acid radical, Thus, an inor-
ganic sulphide consists of a metallic radical combined w ith sulphur
only, while a sulphite and a sulphate are compounds of metallic
radicals with the sulphurows and the sulphurie acid radicals respec
tively, and so on with other inorganic ‘‘ ides,*’ ‘‘ites,’’ or ‘ ates,’’
Potassium Bromide (Potagsii Bromidum, U. 8. P.). —This salt is
analogous in composition with potassium iodide, and is made in
the same way, bromine being substituted for iodine. The for-
mula of bromic acid is HBrO,. It will be noticed that the follow-
ing equations are similar in character to those showing the prep-
aration of potassium iodide;—
6KOH + 8Br, = SKBr + KBrO, + 8H,0
Bromi | Potassium Water
bromate
KBr + 38CO
Potassium Carbonic
bromide oxide
ST Manganate and Permanganate.
8.—Place a fragment of solid potassium hy-
droxide, KOH, with about the same quantity of potassium
chlorate, KCTO, and of black manganese oxide, MnO,, on
a piece of platinum foil.’ Hold the foil, by means of a
emall pair of forceps or tongs, in the flame of a blowpipe for
4 few minutes until the fused mixture has become dark
green—apparently black. This color is that of potassium
mangarate, K,MnQ.,,.
6KOH + KCIO, + 3MnO, = 8K,MnO, + KCl + 3H,0
um Potassium Black man- Potassium Potassium W ater
de chlorate ganesc oxide Wanganate chloride
"The foil may be 1in. broad by 2 in, long. No ordinary flame will
melt the platinum, fused caustic alkalics only slowly corrode it, and
seed few other chemical substances uffect it at all; hence the Se piece
| be used in experiments over and over again. Many metals form a
alloy with platinum, and phosphorus and arsenons sulphide
, pattack it; henee such substances, as we ll as mixtures likely to
should be heated in porcelain vessels.
6
THE METALLIC RADICALS,
Experiment 9.—Potassium Permanganate (Potassii Per-
manganas, U.S. P.), KMnO.. Boil the potassium manga-
nate from Experiment 8 in water fora short time. Potassium
permanganate is formed, and yields a purple solution.
3K,Mn0, + 2H,0 = 2KMnOQ, + 4KOH +4 Mno,
Potassium Water Potuss! aim Potassium Black man-
manganate permanganate hydroxide ganese oxide
On the large scale, the potassium hydroxide set free in the
reaction is neutralized by sulphuric or, better, by carbonic acid,
und the solution is evaporated to the crystallizing point. Manga-
nate may also be changed into permanganate by treatment with
chlorine,
2K,Mn0Q, 4+ Cl, = 2KCl 4+ 2KMn0,
Solutions of potassium manganate (green) or permanganate
(purple) and the analogous sodium compounds so readily yield
their oxygen to organic matter that they are used on the large
scale as disinfectants.
Experiments dealing with the remaining official potassium
compounds (namely, potassium bichromate, arsenite, chlorate,
cyanide, ferrocyanide and ferricyanide), are deferred at present.
Crystallization. —This operation will have been performed sev-
eral times in the course of the foregoing experiments. Obviously
it offers a mode of separating soluble crystallizable substances
from soluble amorphous (a, a, without; ope), morphe, shape),
substances; also of separating from each other, by fractional
crystallization, substances of varying degrees of solubility.
Analytical Reactions of Potassium Salts,
Note.—FEach reaction should be expressed in the form of an
equation or diagram by the stadent in his note book.
1. To a solution of any salt of potassium (chloride,' for
example) add a few drops of hydrochloric acid and of a
solution of platinie chloride in hydrochloric acid (really
chloroplatinic acid, H,PtCl,)* and stir the mixture with a
glass rod; a yellow granular or slightly crystalline precipi-
tate* slowly forms. This precipitate consists of potassium
' A few fragments of potassium carbonate, two or three drops of
hydrochloric-acid, and a small quantity of water, give a solution of
potassium chloride at once, KyCOs + 2HCT=2KC1 + HyO + COs.
* Experiments with reagents containing platinum or other expensive
motals are economically performed in watch-glasses, drops of the liquids
being operated on.
' By precipitation (from preeipitare, to throw down suddenly) is
simply meant the formation of particles of solid in m liquid, no matter
whether the solid, the prreipitate, subside or floats, and po matter
whether the operation be partial or complete.
POTASSIUM, 83
chloroplatinate, K,PtCl,; it is very sparingly soluble in water,
and practically insoluble in alcohol.
Memoranda.—When the precipitate forms very slowly, it is
sometimes of un orange-yellow tint, If potassium iodide happen
to be the potassium salt under examination, compounds of iodine
and platinum will be formed, giving a red color to the solution,
and a en quantity of the precipitant (that is the precipitating
1 il
wai ill be required. .
Kdueational Note.—The thoughtful student will not confuse the
test with the chemistry of the test. The test itself appeals to the
senses; commonly to the eye, sometimes to the nose, occasionally
to the ear, A person may be able to apply a test, and yet never
know anything of the chemistry of the test,
2. Carnot’s test for potassium.—Mix one drop of a solu-
tion of bismuth nitrate with one drop of a solution of sodium
San gen and add to the mixture 10 c.c. or so of absolute
|. To the reagent so prepared, add one or two drops
of a solution of a pores salt. A yellow precipitate of
potassium bismuth thiosulphate, K,Bi(S,O,),, is produced
either immediately or very nearly so (depending upon the
concentration of the solution of the potassium salt added).
If produced in large quantity, the preciptate settles down in
a bulky floceulent form. Although insoluble in nearly
absolute aleohol, the precipitate is readily soluble in water
and in dilute alcohol, hence it is essential that no consider-
able quantity of water should be present. Very dilute solu-
tions of potassium salts should be concentrated by evaporation
before employing them for this reaction.
Potassium Bitartrate, Potassium Hydrogen Tartrate. Acid
Potassium Tartrate.
$. To» solution of any salt of potassium add excess of a
. solution of sodium bitartrate (sodium hydrogen
tartrate ), NaHC,H,0,, and shake or well stir the mixture: a
white granular precipitate of potassium bitartrate (potassium
| ogen tartrate), KHC,H,O, will be formed. If the
| | of potassium salt employed is alkaline (solution of
‘potassium carbonate, for example), care must be taken to
add the ae hydrogen re solution until the liquid,
after thorough mixing, is acid to test paper, otherwise the
* pee ipitate will not be formed. (Solution ieeadiate hydrogn
| 0. possesses a strongly acid reaction.) Test paper, sce
p 99.
84 THE METALLIC RADICALS.
Note.—By ‘‘excess’’ of any test-liquid (such as the “solution
of sodium bitartrate’’ just mentioned) an excessively large
quantity is not to be understood, but merely such a quantity of
the reagent as is more than sufficient (however little more) to
convert the whole weight of the compound attacked into the
compound to be produced, Thus, in the present case, enough
sodium hydrogen tartrate must be added to convert the whole of
the potassium salt operated on into acid potassium tartrate,
What the weight of salt operated on was, must be roughly esti-
mated mentally by the operator. It is not necessary in analytical
operations to know the exact weights of salts employed. The
analyst must use his judgment, founded on his knowledge of the
reaction (as shown by an equation), and of the molecular weights
of the substances employed in the reaction, as well as by the
rough estimate of the amount of material on which he is experi-
menting.
Limits of the test.—Acid potassium tartrate is soluble in 200
purts of cold and in 16.7 parts of boiling water. Hence, in
applying the acid sodium tartrate test for potassium, the solu-
tions must not be hot. Even if cold, no precipitate will be
obtained if the solutions are very dilute. This test, therefore, is
of far less value than either of the two already mentioned, Acid
potassium tartrate is less soluble in dilute alcohol than in water,
so that the addition of alcohol renders the reaction somewhat
more delicate,
Cream of Tartar.—The precipitate is Potassii Bitartras, U.S.P.,
long known as Cream of Tartar (although the official preparation
is not formed in the above manwer),
Potassium and Sodium Tartrate.
4. To some hot concentrated solution of sodium earbonate
(about three parts), in a test-tube or larger vessel, add potas-
sium bitartrate (about four parts) till no more effervescence
occurs; When the solution is cold, crystals of potassium and
sodium tartrate, K NaC HO, 4H,0,( Potassii et Sodii Tartras,
U.S.P.), long known as Rochelle Salt, will be deposited. The
erystals are large rhombic prisms.
Na,CO, + 2K HCHO, = 2KNaC,H,0, + H,O + CO
Sodium Potassium Potassium andsolium Water Carbonile
carbonate biturtrate tartrate anhydride
5. The flame-teat.—Dip the looped end of a platinum wire
into a solution of a potassium salt, and introduce the loop
into the lower part of the flame of a spirit-lamp or Bunsen
burner. <A light violet or lavender tint will be communi.
ented to the flame, an effect highly characteristic of salts of
potass) um.
POTASSIUM, 85
Potassium salts are not readily volatile. Place a frag-
ment of carbonate, nitrate, or other potassium salt, on a piece
of platinum foil, and heat the latter in the flame of «a lamp;
the salt may fuse to a transparent liquid and flow over the
foil; water also, if present, will escape as steam, and black
earbon be set free, if the salt happen to be a tartrate, citrate,
etc.; but the potassium compound itself will not be vaporized
to any appreciable extent unless exposed to an exceedingly
high temperature, This is a valuable negative property, as
will be evident when the analytical reactions of ammonium
come under notice.
6, A solution of sodium cobaltic nitrite' is a very delicate
test for potassium, in the absence of ammonium, potassium
salts forming with it a gts precipitate of potassium cobaltic
nitrite ( Fischer's salt), K,Co( NO,),, even in extremely dilute
solutions.
QUESTIONS AND EXERCISES.
Name the source of potassiam,—Give the source, formula, and charac-
ters of Potassium Carbonate.—What is the systematic name of Caustic
Potash. State the chemical formula of Caustic Potash—Construct an
equation representing the reaction between potassium carbonate and
slaked lime.—Define a hydroxide.—What group of atoms is characteristic
of all carbonates ?— How is " aan Potash” made, and of what
sults is it a mixture ?—What is the formula for the acid radical of all
acetates ?—Draw & diagram showing the formation of Potassium Acetate,
—(live a process for the conversion of carbonates into other salts.—What
js the difference between Potassium Carbonate and and Bicarbonate?
he is the latter prepared ?—What is the relation between salts
os0 specific names end in the sylluble “ale,” and acids ending in“ i¢,"7
pret saat ct diagrams or equations representing the formation of Po-
tassium Tartrate from Acid Tartrate, and Potassium Citrate from Car-
honate—Distingnish between a normal and an acid salt.—How is Potas-
sium Iodide mae ?—Ilustrate the process either by diagrams or equa-
tiona—Calenlate how much potassium jodide is producible from 1000
grins of iodine. Ana., 1308.5 grains.—-Give a method for the detection
of iodate in potassium iodide. Explain the reaction,-~What is the signifi-
cation of the termination “ide in chemical nomenclature ?— State the
relations between sulphides, sulphites, and sulphates. pa wlion the
chemical relation of Potassium Bromide to Potassium Todide.— Describe
the formation of Potassium Permanganate, giving equations or diagrams.
--How do manganates and permangenates act as disinfectants !—Enu-
merate the tests for potassium, explaining by diagrams or equations the
Various reactions which oevur.
— — ——
) Sodium Cohaltic Nitrite Test Solution, U. 8. P., is made by dissolving
4 Gm, of eobaltons nitrate and 10 Gm. of sodium nitrite in HO c. oc, of
water, adding 2 Cyc. of acetic acid and diloting with water to 100, c. ,
86 THE METALLIC RADICALS,
SODIUM: Na. Atomic weight, 22.88.
Occurrence, ete. —Most of the sodium salts met with in phar-
macy are obtained directly from sodium carbonate, which is now
manufactured on an enormous scale from sodium chloride (com-
mon salt, sea-salt, bay-salt, or rock-salt), the most abundant of
the sodium salts, .When pure common salt (Sodii Chloridum,
U.8. P,), occurs as a white crystalline powder or transparent cubic
crystals, free from moisture; the best varieties commonly contain
a little magnesium chloride, and sometimes other impurities,
Besides the direct and indirect use in medicine of sodium carbon-
ate, or ‘carbonate of soda” as it is commonly called, this sub-
stance is largely used for household cleansing purposes, under the
name of ‘‘washing soda,” and in the manufacture of soap,
Sodium nitrate also occurs in nature, but is valuable as a nitrate
rather than as a sodium salt. Sodium in the form of one or other
of its compounds, is a constituent of about forty chemical or
galenical preparations of the Pharmacopeia.
Sodium is prepared by a process similar to that for potassium,
but at a somewhat lower temperature, Castner obtained it com-
paratively cheaply by distillation from a mixture of sodium
hydroxide, carbon and iron, contained in steel vessels. The
modern Castner process for preparing sodium, by which large
quantities are now obtained, consists in electrolyzing fused sodium
hydroxide. The metal has a bright metallic lustre when freshly
cut, but is rapidly attacked by atmospheric oxygen, moisture and
carbonic anhydride, and eventually becomes coated with sodium
carbonate. Thrown upon the surface of water, sodium displaces
hydrogen from the water, yielding solution of sodium hydroxide;
but unless the sodium is confined to one spot, by placing it on a
small floating piece of filter-paper, the action is not sufficiently
intense to cause ignition of the escaping hydrogen. When the
latter does ignite, it burns with a yellow flame, due to the pres-
ence of a small quantity of sodium vapor.
2Na + an), «2. HH. .+ 2Na0H
Sodium Water Hydrogen Sodjum hydroxide
Sodium similarly attacks alcohol, yielding sodium ethylate (see
Index). It may be kept beneath the surface of mineral naphtha,
a Ke sealed tins out of contact with air. It crystallizes in octa-
edra,
Sodium Hydroxide. Caustic Soda.
The formation of solution of sodium hydroxide, or caustic soda,
NaOH, is effected by a process resembling that employed for
making solution of potassium hydroxide, already described.
NaCO, + Ca(OH) = 2NaOH + #£CaCO;
Sadi wi Calcium Sodium Calcium
carbousate hydroxide hydroxide carbonate
SODIUM. 87
The remarks made concerning the general properties of solution
of a hydroxide apply to this solution also.
the Castner process, which is in operation on the manufac-
turing scale, sodium hydroxide (Sodii Mydroridum, U. 8. P.), is
obtained as a product of the electrolysis of a solution of sodium
chloride. The chlorine simultaneously liberated at the anode as
another product of this electrolysis, is used in the manufacture of
bleaching powder (see p. 119).
The interaction of sulphur and sodium carbonate at a high
temperature resembles that of sulphur and potassium carbonate;
but as the product is not used in medicine the experiment may be
omitted. It is mentioned here to draw attention to the general
resemblance of the potassium salts to those of sodium.
Sodium Acetate.
Experiment 1.—Add sodium carbonate (in powder or, bet-
ter, in nts) to some moderately concentrated acetic acid
in an evaporating-basin as long as effervescence occurs, and
than boil off some of the water. When the fluid is cold,
of sodium acetate, NaClH,O,, 83H,O (Sodii Acetaa,
5. P.), will be deposited. ‘A ten percent, solution in
distilled water forms “Sodium Acetate Test Solution,’ U.S. P.
‘om e wae ae Hi 0; + aay pte bs
carbonate ean unhydride
Sodium acetate effloresces (see p. 90) in dry air, and loses all
its water of crystallization when gently heated, It withstands a
ik anes of 270° to 280° F. (about 182° to 138° C.) without
He 9. wpe but above 200° F. (about 149° C.) it rapidly
ts extended formula, isCH,.COONa, 31,0.
Sodium Bicarbonate. Sodium Hydrogen Carbonate.
The action of carbonic anhydride and water on sodium ear-
bonate, Na,CO,, resembles that on potassium carbonate, but
is carried out in a different manner. The result is sodium
bicarbonate, NaHCO, (Sodii Bicarhonas, U.S. P.).
fed’ + HO + co, = 2NaHCO,
Water Carbonic Sodium
anhydride bicarbonate
eeeeunele
\" Experiment 2.—Heat crystals of sodium carbonate, NaCO,,
| ena ogy soda), in a porcelain erucible until no more
— steam Rub the product, in a mortar, with two-thirds
le = of its w t of the same crystallized salt which has not been
M deprived depeived of ic water, and place the powder in a test-tube or
s
88 THE METALLIC RADICALS.
smal] bottle into which carbonic anhydride may be conyeyed
by a tube passing through a cork and terminating at the
bottom of the vessel. To generate the carbonic anhydride, fil]
a test-tube having a small hole in the bottom (or a piece of
wide glass tubing, the lower end of which is plugged by a
grooved cork), with fragments of marble, insert a cork and
delivery-tube, and connect the latter, by means of a piece of
India-rubber tubing, with the
tube leading into the vessel
containing the sodium carbon-
ate. Now plunge the tube
which contains the marble
into a test-glass, or other vessel,
containing a mixture of one
part of hydrochloric acid and
two parts of water, and loosen
the cork of the sodium carbon-
ate tube until carbonic anhy-
dride, generated from the mar-
ble, may be considered to have displaced all the air of this
tube; then replace the cork tightly and set the apparatus aside,
As the gas is absorbed by the sodium carbonate, hydrochloric
acid rises into the tube containing the marble, and generates
fresh gas, which, in its turn, drives back the acid liquid, and
thus prevents the production of any more gas until further
absorption has occurred, When the salt is wholly converted
into bicarbonate, NaHCO,, it will be found to have become
damp through the liberation of some water from the erystal-
lized carbonate, Na,CO,, 1OH,O, (It would be inconveniently
moist, even semi-fluid, if a part of the carbonate had not pre-
viously been rendered anhydrous.) On the large seale, the
resulting bicarbonate may be freed from any carbonate or
traces of other salts, by adding half its bulk of cold distilled
water, setting aside for about half an hour, shaking oceasion-
ally, draining the undissolved portion, and drying it by ex-
posure to the air on filter-paper.
Fig. 19.
Preparation of sodium bicarbonate.
This arrangement of apparatus for the preparation of sodium
bicarbonate may be adopted for potassium bicarbonate, oné part
of potassium carbonate dissolved in two and a half parts of water
being subjected to the action of the gas, and not the solid carbon-
ate, as in the case of the sodium salt.
The sodium carbonate may be placed not in o test-tube or
bottle, but in a vertical tube, the bottom of which is loosely closed
SODIUM. 89
by a grooved cork, Any water of crystallization that is set free
then runs off into a vessel that is placed beneath, and takes with it
impurities (chlorides, sulphutes, ete.), that may have been present
in the original aalt,
The Ammonia Process,
Sodium bicarbonate is now prepared on the manufacturing scale
by treating a concentrated solution of sodium chloride, which has
been saturated with ammonia, with carbonic anhydride under a
pressure somewhat greater than that of the atmosphere. Sodium
jicarbonate, which is sparingly soluble, is slowly precipitated.
The ammonia and the carbonic anhydride may be considered
to behave in the reaction as ammonium bicarbonate.
NH,HCO, + NaCl = NaHCO, + NHCl
Ammoninm Sodium Sodium Ammon itm
toarbonate cbloride bicarbonate chloride
Ammonia is recovered from the resulting ammonium chloride
and is agnin used for saturating solution of sodium chloride which
is to be employed in subsequent operations for preparing further
quantities of sodium bicarbonate. Washing soda, Na,CO,, LOH,O,
is made by heating the bicarbonate thus obtained, and crystal-
lizing from aqueous solution, the carbonic anhydride liberated
during the heating process being also utilized in the preparation
of further quantities of sodium bicarbonate.
2NaHOO, = NaCO, + H,O + CO,
Sodium Sot itinn Water Carbonie
bicarbonate carbonate anhydride
Sodium bicarbonate may be medicinally administered in the
form of lozenge (T'rochicus Sodii Bicarbonatis, U.S. P. ).
Sodium Carbonate.
Sodium carbonate may be obtained by heating the sodium
bicarbonate produced by the ammonia process described above,
the resulting salt being anhydrous.
Sodium carbonate is also prepared on the large scale by the
Leblanc rocess. Sodium chloride is first converted into sul-
phate (aa t-cake) by heating it with sulphuric acid :—
2NaCl + H.SO, = Na,SO, + 2HCI
The sulphate is then roasted with the limestone and amall cont,
sodium carbonate and caleium sulphide being formed: —
| Na,50, + 20 +- CaCO, = CaS + Na,CO, + 200,
The resulting mass (black-ash) is lixiviated. (Livxivia, from /ix,
lye—water impregnated with alkaline sults ; he nee Hatoiation, the
operation of washing i mixture with a v how Lo 1 lissolve out soluble
conmituents, If relatively small quantities of solvents be om-
90 THE METALLIC RADICALS,
ployed, the solution by lixiviation will be more or less fractional,
substances of varying solubility being thus more or less separated
from each other.) The sodium carbonate dissolves, the calcium
sulphide remaining insoluble. The solution is evaporated to dry-
ness, and yields crude sodium carbonate. This is roasted with a
small quantity of sawdust, to reconvert into carbonate any caustic
soda produced by the action of lime on the sodium carbonate,
The product is seda-ash, Dissolved in water and crystallized, it
constitutes ordinary ‘‘ washing-soda’’: recrystallized (and some-
times ground) it forms purified sodium carbonate, Na,CO,, LOH,O.
In the Hargreaves-Bird electrolytic process for the manu-
facture of sodium carbonate, the sodium hydroxide obtained by
the electrolysis of a solution of sodium chloride is treated with a
mixture of steam and furnace gases (the latter furnishing carbonic
anhydride), whereby a solution is obtained which only requires
evaporation to a small extent in order to yield crystals of sodium
carbonate on cooling.
A erystal of decahydrated sodium carbonate is sodium carbonate
plus * water of crystallization '’; on heating it, part or (at 100°C.),
the whole of the water is evolved. The sodium carbonate of the
Pharmacopeia is the monohydrated salt, Na,CO,, H,O (Sodii
Carbonas Monohydratus, U. 8. P.). The decahydrated salt loses
nine-tenths of its water at about 35° C., leaving the monohydrated
salt. The official salt is the latter ‘in the form of a crystalline
granular powder, which is scarcely affected by exposure to air
under ordinary conditions.
Water af Crystallization, —Anhydrous and Hydrous Salts, Ff-
florescence. Anhydrides.—A number of salts, when crystallizing
from aqueous solution, take up water to a greater or Jess extent
from the solution, Sometimes the same salt is capable of com-
bining with water in two or more different proportions. Salts
which do not combine with water in this way are often called
anhydrous (from a, a, without, and Mdwp, Auddr, water) aa dis-
tinguished from those which do, and are, in consequence, called
hydrous salts, The water so taken up by certain salts in erystal-
lizing is generally called water of crystallization, Many hydrous
salts, when simply exposed to moderately dry air at ordinary tem-
peratures, lose water and crumble to a fine powder. This pro-
vess is known as efflorescence (efilorescens, blossoming forth, in al-
lusion to the appearance of the product). The water of erystal-
lization is usually (although not in all cases completely) expelled
from a hydrous salt by heating it to a temperature of 100° to
150° ©. In the chemical formule of salts with water of crystal-
lization, the symbola representing water are usually separated
by a comma, or, as in the U.S. P., by the + sign, from those
representing the salts, The erystals of sodium acetate (Experi-
ment 1, p, 87) are represented by the formula NaC,H,O,, 8H,0,
and those of decahydrated sodium carbonate by the formala
SODIUM, 91
Na,CO,, 1OH,O. It is possible, however, that this so-called water
of erystallization is ina more intimate state of combination than is
indicated by such formule as those just given. An/ydrides form
a distinet class of chemical substances derived from or related to
acids: in short, they may be regarded as acids from which the
elements of water have been removed, the essential chemical proper-
ties of the acids being thereby greatly altered.
Deliqueseence,—Sodium carbonate and potassium carbonate,
chemically closely allied, differ physically. Potassium carbonate
quickly absorbs moisture from the air and becomes damp, wet,
and finally a solution—it is de/iquescent (cdeliquescens, melting
away). Deeahydrated sodium carbonate, on the other hand, is
efflorescent, and yields water of crystallization to the air, the
crystals becoming white, opaque, and pulverulent.
Sodium Hypochlorite.
periment 3.—Triturate in a motar 2 parts of chlorinated
lime with a solution of 1.3 parts of monohydrated sodium car-
bonate in 20 of water, and filter.
[Ca(ClO), 4 CaCl] + 2Na,CO, = 2[NaClO + NaCl] + 2Caco,
inated
Boditm Chlorinated Culelum
Litne carbonate soda carbonate
This solution is an old and very useful disinfectant, formerly
known as Labarraque’s liquor and Kau de Javelle. It contains
about 24 percent, of avaible chlorine.
The official Liquor Soda: Chlorinate: is prepared in a somewhat
analogous manner, but with certain additional details, Jt should
contain at least 2.4 percent. of available chlorine.
Sodium Iodide and Sodium Bromide.
These salts, Nal and NaBr (Sodii Jodidum, U. 8. P., and Sodii
Bromidum, U. 3. P.), are analogous in composition with potassium
iodide and bromide, and“ are prepared by a similar method,
sodium hydroxide being used in place of potassium hydroxide,
Sodium bromide, however, must be crystallized from warm solu-
tions, otherwise, rhombic prisms containing water, NaBr,2H,0,
will be deposited,
Other Sodium Compounds.
Experiments dealing with the chemistry of the remaining im-
portant sodium compounds (namely, nitrate, sulphate, thiosul-
phate, borate, arsenate, valerianate, and ethylate) are deferred for
the present.
Sodium Phosphate.—The preparation and composition of this
salt will be most usefully studied after bone-ash has been
92 THE METALLIC RADICALS.
described. Bone-ash is impure calcium phosphate and is the
starting point for the preparation of most other phosphates and
for phosphorus itself.
Sodii Phosphas Ejfervescens, U.S. P., is made by mixing the
anhydrous phosphate (Sodii Phosphas rsiecatus U, 8. P.), with
sodium bicarbonate and tartaric and citric acids,
Sodium peroxide, Na,OQ,, & compound now manufactured on
a large scale, is used as a bleaching agent, and in chemical
analysis as an oxidizing agent.
Analogies of Sodium and Potassium salts,—Other reactions
similar to those given under potassium might be mentioned
here, and the preparation of sodium citrate, (Sodti Citras, U.S. P.),
iodate, bromate, chlorate, (Sodii Chloras, U. 5. P.), manganate,
permanganate, and many other salts be described. But enough
has been stated to show how sodium is chemically analogous to
potassium. Such analogies will frequently present themselves,
Substitution of Potassium and Sodium salts for cach other.—
Sodium salts being cheaper than potassium salts, the former may
sometimes be economically substituted. That one is employed
rather than the other, is often merely a result due to accident or
fashion. But it must be borne in mind that in some cases a
potassium salt crystallizes more readily than its sodium analogue,
or that a sodium salt is unchanged by exposure to the air when
the corresponding potassium salt has a tendency to absorb moist-
ure; or one may be more soluble than the other, or the two may
have different medicinal effects, For these or similar reasons, a
potassium salt has come to be used in medicine or trade instead
of the corresponding sodium salt, and vice versdé, When a salt is
employed as a source ofa particular acid radical, the least expensive
salt of that radical is nearly always selected,
Analytical Reactions of Sodium Salts,
1. The chief analytical reactions for sodium is the flame-test.
When brought into contact with a Bunsen flame in the manner
described under potassium (page 84), an intensely yellow color
is communicated to the flame by any sodium salt. This is
highly characteristic—indeed, almost too delicate a test; for if
the end of the wire be touched by the fingers, enough sodium
galt (which is contained in the moisture of the hand) adheres
to the wire to communicate a very distinct sodium reaction to
the flame. These statements should be experimentally yeri-
fied, sodium chloride, sulphate, or other salt being employed.
2, Sodium salts, like those of potassium, are not volatile,
Prove this fuct by the means described where the effect of
heat on potassium salt is referred to (p, 85).
AMMONIUM. 93
QUESTIONS AND EXERCISES.
+ Explain the action of sodium on water. What colors do sodium and
ee respectively communicate to flame ?—Sodium acetate: give
ja and preparation, with equation.—Give a diagram showing the
formation of Sodium Bicarbonate. —Why is a mixture of dried and un-
dried salium carbonate employed in the preparation of the bicarbonate ?—
State the difference between anhydrous and crystallized sodium carbon-
ate.— Define the terms anhydrous, hydrous, anhydride,—What do you under-
stand by water of crystallization ?—What is the systematic name of
Rochelle Salt, and how is the salt prepared /—What is the relation of
Rochelle Salt to creamof tartar and tartaric acid ?—Give the mode of
preparaton of the official Solution of Chlorinated Sodu, representing the
by a diagram.— Define deliquescence, efllorescence, and lixipiation, —
Seer sxe podium salts distinguished from those of potassium ?
AMMONIUM,
Radical of the ammonium compounds, NH,.
The elements nitrogen and hydrogen, in the proportion of
one atom of the former to four of the latter,( NH, ), are present
in all the ammonium compounds about to be studied, playing
the part of metallic radical just as potassium (K) and sodium
(Na) do in the potassium and sodium compounds. The group
NH, is univalent like potassium and sodium, and the am-
monium compounds closely resemble those of potassium and
sodium. Ammonium is said to have been isolated by Weyl,
asan unstable dark-blue liquid possessing a metallic lustre,
Source.—The source of nearly all the ammonium salts met
with in commerce is the ammonia gas, NH,, produced during
the distillation of all kinds of coal in the manufacture of ordinary
illuminating gas and of coke. This ammonia is no doubt derived
from the nitrogen of the plants from which the coal has been
produced, It is obtained as a by-product in the distillation of
shale for the production of paraffin oil, and is also recovered from
the furnace gases of iron-works. It is possible, however, to pro-
dice ammonia from its elements, Thus when electric sparks are
through a mixture of nitrogen and hydrogen, or when a
similar mixture ia passed over spongy platinum, some ammonia is
produced. According to Rickman and Thompson, coal-duat, air
and vapor of water, all at a red heat, yield ammonia. Salt added
to the mixture prevents the combustion of ammonia formed, and
ammonium chloride sublimes.
Ammonium Chloride,—The ammonia liberated from the ‘unmo-
Hiacal liquor’ of the gas-works by heat and by the concurrent
detion of slaked lime on the ammoniam hydrosulphide, carbon-
‘ite, and other salts present, when passed into hydrochloric acid,
94 . THE METALLIC RADICALS.
yields crude ammonium chloride (salammoniac), NH, + CH!
=NH,Cl; and from this salt, purified, the others used in phar-
macy are directly or indirectly made. Ammonium Chloride
(Ammonii Chloridum, U. 8. P.), occurs in colorless inodorous
minute crystals, or in translucent fibrous masses, tough and diffi-
cult to powder, soluble in water and in alcohol (90 percent. ).
Commercial ammonium chloride generally contains slight traces
of iron oxychloride, tarry matter, and possibly compound am-
monium chlorides (see “Artificial Alkaloids’ in Index).
Ammonium Sulphate, (NH,)8O,, is formed when the ammonia
of the ammoniacal liquor is neutralized with sulphuric acid, It
is largely used as a constituent of artificial manure; and when
purified by recrystallization, is employed in pharmacy for pro-
ducing the double ammonium and ferric sulphate (iron alum),
Voleanie Ammonia,—A very pure form of ammonia is that met
with in volcanic districts, and obtained as a by-product in the
manufacture of borax, Crude boric acid as imported contains 5
to 10 percent. of ammonium salts, either sulphate or that salt
united with magnesium, sodium, or manganese sulphates, forming
so-called double salts (| Howard).
Ammonium Amalgam.
Experiment 1.—To forty or fifty grains of mercury in a
dry test-tube, add one or two small pieces of sodium (freed
from adhering naphtha by gentle pressure with a piece of filter-
paper), and gently warm the tube, when the metals will unite
with evolution of heat to form sodium amalgam, To this
amalgam, when cold, add some fragments of ammonium chlo-
ride and a concentrated solution of the same salt. The
sodium amalgam rapidly swells up and may even overtlow
the tube. The light spongy mass produced is the so-called
ammonium amalgam, and the reaction is usually adduced as
evidence of the existence of ammonium. ‘The sodium of the
amalgam unites with the chlorine of the ammonium chloride,
while the ammonium is supposed to form an amalgam with
the mercury. At ordinary temperatures the amalgam rapidly
gives off hydrogen and ammonia gases; this decomposition is
nearly complete after some minutes, and mercury remains,
together with the solution of sodium chloride.
Ammonia Water. Ammonium Hydroxide.
Experiment 2.—Heat a few grains of ammonium chloride
with about an equal weight of calcium hydroxide (slaked lime)
moistened with a little water in a test-tube ; ammonia gas is
AMMONIUM. 95
given off, and may be recognized by its pungent odor. It is
very soluble in water. By means of a cork and -delivery-
tube, fitted as described for the preparation of oxygen and of
hydrogen, pass some of the ammonia into another test-tube
containing a little water. The end of the delivery-tube should
only just dip beneath the surface of the water (or possibly, all
the water might rush back into the generating tube, on ac-
count of the water greedily absorbing the ammonia gas). A
solution of ammonia will thus be formed.
2NH,Cl + Ca(OH), = CaCl, + 2H,O + 2NH,
Ammonium Calcium Calcium Water Ammonia
chioride hydroxide chloride
A molecule of ammonia is composed of one atom of nitrogen
with three atoms of hydrogen; its formulais NH,. Two volumes
of the gas contain one volume of nitrogen combined with three
volumes of hydrogen. Its constituents have, therefore, in com-
bining suffered condensation to one-half of their original bulk.
The solution obtained by dissolving ammonia in water is believed
to contain ammonium hydroxide, NH,OH, the analogue of potas-
sium hydroxide, KOH, or sodium hydroxide, NaOH, The chemical
for this belief are the observed analogies of the well-known
ammonium salts with those of potassium and sodium, the similarity
of action of solutions of caustic potash, caustic soda, and ammonia
on sults of most metals, and the asserted existence of crystals of
an a sulphur salt (NH,SH). The formation of ammonium
hydroxide may be illustrated by the following equation: —
NH, + HO = NH. OH
Ammonia Water Ammonium
hydroxide
Solutions of Ammonia, prepared by the above process on a large
scale and in ope apparatus (bottles being so arranged in a series
as to condense all the ammonia evolved during the operation), are
used in pharmacy—the one (sp, gr. 0.897) containing 28 percent.,
the other (ap. gr. 0.958) 10 percent. by weight of ammonia, NH,
{Aqua Ammonia Fortior and Aqua Ammonia, U.S. P. Ine part,
measure, of the former, and two of water are mixed in order to
the latter).
Spiritus Ammonie, U. 8. P., is alcohol (92.3 percent. ), contain-
ing 10 percent. by weight of ammonia, NH,.
Ammonium Acetate.
ee ain diluted acetic acid in a test-tube add
ammonium carbonate until effervescence censes,
cont the liquid, after well stirring or shaking, or perhaps
THE METALLIC RADICALS.
warming, to get rid of carbonic anhydride, is only faintly acid
to litmys (see p. 99). This solution, when of prescribed
strength, forms the official Solution of Ammonium Acetate,
NH,C,H,O, (Liquor Ammonti Acetatis, U. S. P.). On
evaporating and cooling, ammonium acetate may be obtained
in crystals, but some of the salt will then have undergone de-
composition into ammonia and acetic acid. In the rare case
of exact neutrality being required, to the liquid which has
been made slightly alkaline with excess of ammonium carbon-
ate add acetic acid, finally drop by drop, until a drop of the
resulting solution no longer gives a white precipitate with a
drop of a clear solution of ordinary lead acetate (on a piece
of glass backed by black paper or black cloth),
NH,HCO,, NH,NH,CO, +-3HC,H,0,=3NH,C,H,6, + H,0+ 20,
Ammonium acid carbonate Acetic Ammonium Water Carbonic
und carbamate acid acetate anhydride
Solution of ammonium acetate can, of course, also be made by
the interaction of acetic acid and ammonia water; but the liquid,
owing to the absence of dissolved carbonic acid, is too vapid for
medicinal use,
Ammonium Carbonates.
. Commercial ammonium carbonate is made by heating a mixture
of calcium carbonate and ammonium chloride; calcium chloride,
CaCl,, remains, while water, H,O, and some ammonia, NH,,
escape, and the ammoniacal carbonate distils or, rather sublimes !
in cakes (Ammonii Carbonas, U.S. P.). The best form of apparatus
to employ is a retort with a short wide neck and a cool receiver.
On the large scale the retort is usually iron, and the receiver
earthenware or glass; on the small scale glass vessels are employed.
The salt is purified by resublimation at a low temperature—
150° F. (65.5° C.) is anid to be sufficient.
The salt, the empirical formula of which is N,H,,C,O,, is prob-
ably a mixture of one molecule (sometimes two) of ammonium
hydrogen carbonate (ammonium bicarbonate), NH,HCO,, and
one of a salt termed ammonium carbamate, NH,NH,CO,, The
latter belongs to an important class of salts known as carbamates,
but is the only one of direct interest to the pharmacist. Cold
water extracts it from commercial ammonium carbonate, leaving
the greater part of the bicarbonate undissolved if the amount of
' Sublimation (from sublimis, high) is the term applied to the evaporiza-
Hon of w solid substance by heat, and its subsequent condensation on an
upper and cooler part of the vessel or apparatus in which the operation
is performed. The product of sublimation is called » sublimafe, TDif-
ferent substances sublime at different temperatures, hence a mixtore of
volatile solids may sometimes be separuted or fractionated by sublimation.
AMMONIUM, 97
water used be very small. Alcohol also attracts the carbamate,
leaving the bicarbonate undissolved. In contact with water the
carbamate soon changes into normal ammonium carbonate:—
NH,NH,CO, + H,O = (NH,),CO, ; so that an aqueous solution
of commercial ammonium carbonate contains both hydrogen, am-
monium carbonate,and normal ammonium carbonate, If to such
a solution, some ammonia be added, a solution of normal am-
monium carbonate is obtained: this is the common reagent found
on the shelves of the analytical laboratory, Thus, ‘* Ammonium
Carbonate Test Solution,’’ U. 8. P., is prepared by dissolving the
commercial sult in water to which solution of ammonia has been
added.
NH,HCO, NH,NH,CO, + NH,OH = 2(NH,),CO,
Normal ammonium carbonate is the salt formed on adding con-
centrated solution of ammonia to the commercial carbonate in
preparing a pungent mixture for toilet smelling-bottles; but it is
unstable, and on continued exposure to air is converted into a
mass Of crystals of bicarbonate.
Ifammonium carbonate contain more than traces of empyreu-
matic matters (from the gas-liquor), an aqueous solution of it,
with excess of sulphuric acid added, will at once decolorize a
dilute solution of potassium permanganate.
Sal Volatile (Spiritus Ammonia Aromaticus, U.S. P.), is a spirit-
nous solution of about 1 percent. of ammonia, NH,, nearly 4 per-
cent. of normal ammonium carbonate; (NH,),CO,, with oils of
nutmeg, lemon, and lavender flowers. Commercial samples con-
tain salts equivalent to from 1 to nearly 3 percent, of ammonia,
the official spirit yielding a total of nearly 2) percent. of the gas.
Ammonium Nitrate.
Experiment 4.—T some dilute nitric acid add “ammonium
carbonate,” until, after well stirring, a slightly anmoniacal
odor remains. The solution contains ammonium nitrate.
NH HCO, NH,NH,CO,+ 3HNO,=8NH,NO,+ H,O + 2C0,
Ammonium hydrogen carbonate Nitric Ammonium Water Carbonic
and carbamate acid nitrate anhydride
From a concentrated hot solution of ammonium nitrate, crys-
tala may be obtained containing much water (NH,NO,, 1: 2H 0).
On heating these in a dish to about 320° F. (160° | C. y ‘the water
eacapes, The fused Salinicons salt remaining (NH, NO .) may be
poured out on an iron plate, On further heating the fuse i nitrate,
at 350° to 450°F. (about 177° to 232°C.), it is resolved into
Sares oxide or langhing-qas and water, NH, NO, = N, 0 + 2H, 0.
oxide is prepared in this way. for use as an- ang westhe tie, .,
7
THE METALLIC RADICALS.
When required for inhalation, it is washed from any trace of
nitric acid or nitric oxide by being passed through solution of
potussiuin hydroxide and solution of ferrous sulphate, the former
absorbing acid vapors, the latter nitric oxide. It is slightly soluble
in warm water, more so in cold, It supports combustion almost as
well as oxygen. By the application of sufficient pressure it may
be reduced to a colorless liquid, and by simultaneous cooling it
ean be solidified. Inhalation of a mixture of nitrous oxide and
air causes laughter or other excitement.
Ammonium Citrate, Phosphate and Benzoate.
Experiment 5.—To a solution of citric acid, H,C,H,O,, add
ammonia water until the well-stirred liquid smells faintly of
ammonia. Ammonium phosphate, (NIH,),HPO, aud am-
monium benzoate, NH C,H,O, (Ammonii Benzoas, U.S. P.),
are also made by adding ammonia water to phosphorie acid,
H,PO,, and benzoic acid, HC,H,O,, respectfully, evaporating
(keeping the ammonia in slight excess by adding more of its
solution), and setting aside to crystallize.
H,0,H,0, + 8NH,OH (NH,),C,H,0, + 8H,0
Citric acid Ammonium Ammonium citrate Water
hydroxide
H,PO, + 2NH,OH -= (NH,),HPO, + 2H,0
Phosphoric acid Ammonfym Ammonium phosphate Water
hydroxide
HN,H.O, + NH,OH = NH,C,H,O, + H,O
Benzoic acid Ammonium Ammonium benzoate Water
hydroxide
Ammonium phosphate oceurs in transparent colorless prisms,
soluble in water, insoluble in alcohol: ammonium benzoate occurs
in crystalline plates, soluble in water and in alcohol. An ex-
tended formula for ammonium benzoate is C,H,.COONH,; for
immonium citrate, C,H,OH.(COONH,),.
Ammonium Bromide, NH,Br, (Ammonti Bromidum, U. 8. P.),
will be noticed in connection with Hydrobromic Acid and other
Bromides. Ammonium Iodide, NH,I, is also official (Ammonii
fodidum, U. 8. P.).
Ammonium Oxalate.
Experiment 6.—To « nearly boiling solution of 1 part of
oxalic acid in about 8 of water add ammonium carbonate
until the liquid is neutral to test-paper (see following para-
graphs), filter while hot, and set aside to crystallize, The
product is Ammonium Oxalate, U, 8. P,, (NH, ) CLO), HLO,or
(COONH,),, H,O. A solution of it is used as a reagent in
AMMONIUM. 99
analysis ; 1 pose of the pure salt in 25 of water forms
Ammonium late Test Solution, U. 8. P. A
$H,C,0, + 2N,H,C,0, = 3(NH,)C,0, + 4C0, + 2H,0
Ammoni um Ammonium Carbonic Water
acid aoherente oxalate anhydride
Neutralization. —Thus far the methods by which the student has
avoided excess of either acid matter on the one hand, or alkaline
on the other, have been the rough aid of taste, cessation of etler-
yescence, presence or absence of odor, etc. More delicate aid is
afforded by ¢ext-papers,
Test-papers,— Litmus is a blue vegetable pigment, prepared from
various species of Hoecella lichen, exceedingly sensitive to the
action of acids, which turn it red. When the reddened, alkalies
(caustic potash or soda, and ammonia), and other soluble hydrox-
ides, also alkali-metal carbonates, etc., readily turn it blue. The
student should here test for himself the delicacy of this action by
experiments with paper soaked in solution of Titnius and dipped
into very dilute solutions of acids, acid salts (¢.g., KHC,H,O,),
alkalies, and such neutral salts as potassium nitrate, sodium sul-
phate, or ammonium chloride,
Litmus Test Solution (U.S. P.).—This is prepared from purified
litmus, Gently boil litmus with four times its bulk of alcohol
for an hour. Pour away the fluid and repeat the operation twice.
Digest the residual litmus in cold distilled water and filter; then
extract the residue with five times its weight of boiling water, and,
after thoroughly cooling, filter.
Blue litmus-paper (U.8.P.), is made by impregnating unglazed
white with a solution of litmus. Fed litmus-paper (U.S.P.),
is by impregnating unglazed white paper with solution of
litmus, reddened by the previous addition of a very minute quan-
tity of hydrochloric acid.
Turmeric paper (U. 8. P.), similarly prepared from Turmeric
Tineture (U. 8. P.), is occasionally useful as a test for alkalies,
which turn its vat la to brown; acids do not affect it. Several
other ‘indicators’ of alkalinity or acidity are used, such as
Methy! Orange, Phenol-phthalein, and Cochineal Test Solutions.
Ammonium Hydrosulphide and Sulphide.
b 7.—Pass hydrogen sulphide, HS, through a
smal] quantity of ammonia water in a test-tube, until « por-
tion of the liquid no longer causes a white precipitate in solu-
tion of magnesium sulphate; the product is a solution of ammo-
tium hydrosulphide, NH SH.
NH,OH -+- HS — NH SH + H,0
“Ammonium Sulphide Test Solution,” U. 8. P., is made by
100 THE METALLIC RADICALS.
saturating 3 parts by measure of ammonium water with washed
hydrogen sulphide, and then adding 2 parts by measure of
ammonia water, The solution should be preserved in a well-
stopped bottle.
Hydrogen Sulphide or sulphuretted hydrogen is a poisonous
gas possessing an unpleasant odor; hence the above operation
and many others, described farther on, in which this gus is
indispensable, must be performed in the open air, or in a
jJume-cupboard—a chamber so contrived that noxious gases
and yapors shall escape into a chimney in connection with the
external air. In the above experiment, the small quantity
of gas required can be made in a test-tube. Place some
fragments of ferrous sulphide, FeS, in a test-tube, add water
and then sulphuric acid; the gas is at once evolved, and may
be conducted by a tube into the ammonia water. Ferrous
sulphate remains in solution in the generating tube :—
FeS + H,SO, = HS + FeSO,
As heat is not necessary in the preparation of sulphuretted
hydrogen, “Hydrogen Sulphide,” U. 8. P., the test-tube of
the foregoing operation may be advantageously replaced by a
bottle, especially when larger quantities of the gas are re-
quired. In analytical operations, the gas should be purified
by passing it through water, contained in a second bottle,
Fra, 20.
Hydrogen sulphide apparatus,
A convenient apparatus for experimental use is arranged
as follows :—Two common wide-mouthed bottles are selected,
the one haying a capacity of about half a pint, the other a
quarter pint; the former may be called the generating-bottle,
the latter the waah-botile. Fit both bottles with good sound
AMMONIUM,
corks. Through each cork bore two holes of such a size that
glass tubing of about the diameter of a quill pen shall fit
them tightly. Through one of the holes in the cork of the
Seatratiog hore pass a funnel-tube, so that its extremity may
nearly reach the bottom of the bottle, To the other hole
adapt a piece of tubing, 6 inches long, and bent in the middle
toa right angle. A similar “ elbow-tube ” is fitted to one of
the holes in the cork of the wash-bottle, and another elbow-
tube, one arm of which is long enough to reach near the
bottom of the wash-bottle, is fitted to the other hole. Re-
moving the corks, two or three ounces of water are now
poured into each bottle, an ounce or two of ferrous sulphide
put into the generating-bottle, and the corks replaced. The
elbow- tube of the generating-bottle is now attached by a short
piece of India-rubber tubing to the long-armed elbow-tube of
the wash-bottle, so that gas coming from the generator may
through the water in the wash-bottle. The delivery-tube
of the wash-bottle is then lengthened by attaching to it, by
means of India-rubber tubing, another piece of glass tubing
several inches in length. The apparatus is now ready for use,
Concentrated sulphuric acid is poured down the funnel-tube in
small quantities at a time, until brisk effervescence is estab-
lished, and more is added from time to time as the evolution
of gas becomes slow. The gas passes through the tubes into
the wash-bottle, where, as it bubbles up through the water,
any trace of sulphuric acid, or other matter mechanically
earried oyer, is arrested, and thence the gas flows out at the
delivery-tube into any vessel or liquid that may be placed
there to receive it. The generator must be detached occa-
sionally, and the ferrous sulphate washed out of it. Should
difficulty he experienced in obtaining sufficiently sound corks
to make gas-tight fittings for the apparatus, double-bored
rubber stoppers, obtainable from any apparatus dealer, may
be setadined:.
Hydrogen sulphide disswlves in water to a moderate extent,
yielding a solution which smells strongly of the gas, and is
frequently employed as a reagent. When the ‘solution is
ex to air the hydrogen sulphide rapidly unde. OES
oxidation with deposition of white sulphur :—
2H.5 + O,= 2H,O +8,
THE METALLIC RADICALS.
Analytical Reactions of Ammonium Salts,
1. To asolution of an ammonium salt (ammonium chloride,
for example), in a test-tube, add solution of sodium hydroxide
(or potassium hydroxide, or slaked lime), and warm the
mixture; a characteristic odor (ammonia, NH,) results :—
NH,Cl+ NaOH—NH,+ H,0 + NaCl.
The recognition of the odor of ammonia is one of the
readiest means of detecting the presence of this substance;
but the following tests are occasionally useful. Into the
upper part of the test-tube insert a glass rod moistened with
euncentrated hydrochloric acid (that is, with the aqueous
solution of hydrochloric acid gas conventionally termed
hydrochloric ‘acid, the Acidum Hydrochloricum of the
Pharmacopoeia ); rhite fumes of ammonium chloride will
be produced :—NH,-+HCI—=NH,Cl. Hold a piece of moist
red litmus-paper in a tube from which ammonia is being
evolved ; the color will be changed to blue.
Though ammonium itself cannot be obtained in the free state,
its compounds are stable. As the foregoing experiment shows,
ammonia is easily expelled from these compounds by the action
of the stronger alkalies, caustic potash, caustic soda, or slaked
lime. As a useful exercise, the student should here construct
equations in which ammonium acetate, NIH,C,H,N,, sulphate,
(NH,),80,, nitrate, NH,NO,, or any other ammonium salt, is
supposed to be under examination; also equations representing
the use of the other hydroxides, KOH or Ca(OH ),.
2. To a few drops of a solution of an ammonium salt, add
a drop or two of chloroplatinie acid, H,PtCl; a yellow erys-
talline precipitate of ammonium ¢ hloroplatinate, (NH,),PtCl,,
will be produced, similar in appearance to the corresponding
potassium salt, the remarks concerning which (see p. 82) are
equally applicable to the precipitate under notice.
To a moderately concentrated solution of ammonium salt
add a saturated solution of sodium bitartrate, and shake well
or stir the mixture; a white granular precipitate of ammonium
bitartrate (acid ammonium tartrate) will be formed.
For data from which to construct an equation representing this
action, see the remarks and formule under the analogous potas-
sium salt (p. 83).
4. Evaporate a few drops of a solution of an ammonium
salt to dryness, or place a fragment ofa solid ammonium salt
LITHIUM. 103
on a piece of platinum foil, and heat in a flame; the salt is
readily volatilized, usually with decomposition. As already
notioed, the salts of potassium and sodium are fixed (4, ¢., non-
volatile) under these circumstances, a point of difference of
which adyantage is frequently taken in analysis. A porcelain
crucible may often be advantageously substituted for platinum
foi) in experiments on volatilization.
Salts of ammonium with the more complex acid radicals seldom
volutilize unchanged when heated. The oxalate, when so treated,
loses its water of crystallization, and ata higher temperature decom-
poses, yielding carbonic oxide, carbonic anhydride, ammonia gas,
water, and several organic substances. The phosphate loses water
and ammonia, and yields a residue of metaphosphoric acid.
A wire triangle may be used in supporting crucibles (Fig. 21).
It is made by twisting together each pair of ends of three (5- or 6-
inch) crossed pieces of wire (Fig. 22). A piece of tobacco-pipe
stem (about 2 inches) is sometimes placed in the middle of each
wire before twisting, the transference of any metallic matter to
the sides of the crucible being thereby prevented (Fig. 23),
Fra. 22. Fira. 23.
aieevlax supports for crucibles.
LITHIUM : Li. Atomic weight, 6.98.
Lithium is widely distributed in nature, but is usually in
minute proportions as compared with other elements. A trace of
it may be found in most soils and waters, a certain spring in
Cornwall containing even considerable quantities as chloride.
Lithiom carbonate, Li,CO,, (Lifhii Carbonas, U.S. P.), is a
white granular powder obtained from the minerals which contain
lithium—namely, lepidolite (from Aric, fepia, a seale, and AiBue,
lithoa, a stone, referring to its scaly appearance); triphane (from
tpelc, treia, three, and paiva, phaind, I shine) or spodumene (from
arodéu, spoddé, I reduce to ashes, in allusion to its exfoliation in
104 THE METALLIC RADICALS.
the blow-pipe flame); and petalite (from +éradov, petalon, a leaf,
referring to its laminated character), Each contains aluminium
silicate, with potassium and lithium fluoride in the case of Aus-
trian lepidolite (which is the most abundant source) and sodium
and lithium silicates in the others. To separate the lithium,
lepidolite is decomposed by sulphuric acid; alumina, etc., precip-
itated by ammonia; the filtrated evaporated and the residue
ignited. The resulting sulphates are dissolved in water and lithium
carbonate is precipitated by adding a solution of a carbonate.
The preparation of common alum is sometimes made a part of the
factory processes. Lithii Carbonas, U.S. P., is soluble in 75 parts
of water at 25°C. and in 140 at 100° C,
Lithium citrate (Lithii Citras, U, 8. P.), is used in medicine,
It occurs in white deliquescent crystals or powder, prepared
by saturating citric acid with lithium carbonate. The crystals
have the formula Li,C,H,O,, 4H,O; dried at 212° F, (100° C.),
| i
Li,C,H,0,, H,O (Umney).
sLi,cO, + 2H,C,H,O, = 2Li,C,H,0O, + 8H,O + 3CoO,
Lithium Citric acid | Lithium Water Carbonic
carbonate j citrate anhydride
Lithium citrate should yield by incineration 52.8 percent. of
white lithium carbonate. Lithiit Citras Effervescena, U.S. P., is
prepared by mixing lithium citrate with citric and tartaric acids
and sodium bicarbonate, then heating and stirring until the mixt-
ure assumes a granular character,
Other official salts of lithium are Lithii Benzoas, U. 8 P.,
LiC,H,0O,; Lithii Bromidum, U. 5. P., LIBr; and Lithii Salieylas,
U.S. P., LiG,H,O,.
Lithium urate is more soluble than sodium urate; hence lithium
preparations are administered to gouty patients in the hope
(apparently quite unintelligible on any chemical grounds) that
sodium urate, with which such systems are loaded, may be con-
verted into lithium urate and removed.
In its analytical behavior, lithium stands in some respects
between the alkali-metals potassium and sodium, and the metals
of the barium group (barium, strontium, and calcium) its hydrox-
ide, carbonate, and phosphate being only slightly soluble in water,
Lithium chloroplatinate, Li,PtCl,, is soluble in water and alcohol.
The atom of lithium is univalent, Li,
Analytical Reactions of Lithium Salts.
1, To a solution of lithium chloride, LiCl (obtained by
dissolving a few grains of lithium carbonate in dilute hydro-
chloric acid), add a solution of ordinary sodium phosphate,
Na, HPO,, and a little sodium hydroxide, or ammonia water,
' {rates will be considered subsequently in connection with uric acid.
LITHIUM. 105
and boil. A white crystalline precipitate of lithium phos-
phate is produced :—
$LiCl + Na,HPO, + NaOH — Li,PO, + 3NaCl + H,O
2. Moisten the end of a platinum wire with a solution of
a lithium salt, and introduce it into the flame of a Bunsen
burner or spirit-lamp; a magnificent crimson tinge is im-
parted to the flame.
The light thus emitted by incandescent lithium vapor is of a
purer crimson than that given by strontium. When the flames
are examined by means of the spectroscope the red rays are,in the
case of strontium, found to be associated with blue and yellow,
neither of which is observed in the lithium light.
Qualitative Analysis,
With regard to those of the preceding experiments which are
useful rather as means of detecting the presence of potassium,
sodium, ammonium, and lithium (the so-called ‘‘tests’’), than as
illustrating the preparation of salts, the student should proceed to
apply them to certain solutions of any of the salts of these metallic
icals with the view of ascertaining which radical is present;
that is, proceed to practical analysis.’ A little thought will enable
him to apply the reactions in the most suitable order and to the
beat advantage for the contemplated purpose; but the following
arrangements are perhaps as good as can be devised :—
Di REcTIoNs FOR APPLYING THE ANALYTICAL REACTIONS
DESCRIBED IN THE FOREGOING PARAGRAPHS TO THE
ANALYSIS OF AN AQUEOUS SOLUTION A SALT OF ONE OF
{HE METALLIC RADICALS, POTASSIUM, SODIUM, AMMONIUM,
LITHIUM.
To a small portion of the solution to be exantined, in
test-tube, add sodium hydroxide test solution, and warm the
' Such solutions are prepared in educational laboratories by « tutor.
ahow auder other circumstances, be mixed by a friend, as it is
not esirable for the student to know previously what is contained in the
substance he is about to analyze.
analysis of solutions containing only one salt serves to impress
the memory with the characteristic tests for the various me rhallie and
other r Is, and familiarize the mind with chemical principles. Me “ili-
cal students seldom have time to go further than this. More thorough
and general chemical knowle dwe is only ac “quired by working
on such mixtures of substances ns are met with in actual practice, - begin-
ning ¥ solutions which may contain any or all of the mem mbe rs of a
’ in this Manual two tables of short analytical directions are
eee ee srs. Pharmaceutical students should follow the second,
»
106 THE METALLIC RADICALS.
mixture; the odor of ammonia gas reveals the presence of an
ammonium salt.
To a few drops of the solution, apply the bismuth thio-
sulphate test for potassium (p. 83); a yellow precipitate
. indicates the presence of potassium. Potassium may also be
detected by means of the chloroplatinic acid test, but only in
the known absence of ammonium salts,
The flame-test is sufficient for the recognition of sodium or
of lithium.
DIRECTIONS FOR APPLYING THE ANALYTICAL REACTIONS
DESCRIBED IN THE FOREGOING PARAGRAPHS TO THE
ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF ONE OR
MORE OF THE ALKALI-METALA,
I. In cases when it is not necessary to effect actual separation
of the metallic radicals present, the examination of the solution
may best be carried out by making special tests for each of them
as below :—
To a small portion of the solution in a test-tube, add sodium
hydroxide and warm the mixture; the odor of ammonia reveals
the presence of an ammonium salt.
Apply the bismuth thiosulphate test for potassium to a few
drops of the solution (p, 85). The formation of a yellow pre-
cipitate indicates the presence of a potassium salt, !
To another portion of the solution add sodium phosphate and
then ammonia water until the liquid, after shaking, smells of
ammonia, and boil. The formation of a white precipitate indi-
cates the presence of a lithium salt. Test for lithium also by the
flame-text.
The flame-test is sufficient for the recognition of sodium unless it is
present in small! quantity along with much lithium. In such a case
the spectroscope may be employed. Traces of lithium may also be
detected in presence of much sodium by means of the spectroscope.
Note on the flame-test.—When the violet tint imparted to the
flame by potassium salts is masked by the intense yellow color
due to sodium, it may still be recognized, in the absence of lithium
salts, if the lame be observed through a piece of dark-blue glass,
a medium which absorbs the yellow rays of light but allows the
violet rays to pass, It is not safe to examine a solution for
potassium by the flame-test in the known presence of lithium salts,
II. Should it be necessary actually to separate the metallic
radicals from one another, the analysis may be carned out ac-
cording to the following method :
11f an ammoniam salt be present, it is desirable to get rid of it as
duseribed under IT., before applying this test for potassium,
LITHIUM. 107
Commence by testing a small portion of the solution for an
ammonium salt; if it be present it must be got rid of prior to
testing for (and if present, removing) potassium as chloropla-
tinute. Evaporate the remainder of the original solution to dry-
ness in a small basin, transfer the solid residue, by instalments if
necessary, to a porcelain crucible, and heat the latter to low red-
ness until white fumes, due to the decomposition of ammonium
salts, no longer escape (see Fig. 19). This operation should be
conducted in a fume-cupboard, to avoid contamination of the air of
the laboratory. When the crucible has cooled, dissolve the solid
residue in a small quantity of hot water, filter if necessary, add
excess of chloroplatinic acid (i. ¢., add sufficient of the reagent to
convert the whole of the alkali-metals present into chloropla-
tinates) and evaporate to dryness on a water-bath, or at any rate
at a temperature not exceeding 100° C. Digest the residue for
some time with alcohol, and filter :—
8 am —EE
Residue —A heavy | Filtrate—May contain sodium and lithium
yellow powder con- chloroplatinates, with excess of chloroplatinie
sitting of potassium | acid. Evaporate or distil off the aleohol, and
tga a heat to redness the brown solid which remains,
K,PtCl,. Wash with | Treat the residue with hot water, and filter:
alcohol; dry; trains
fer to a porcelain Reaidue.— Filtrate.—May contain NaCl
ey and heat | Consists of | and LiCl. Evaporate to dry-
¥
gradaally up to red- | platinum. | ness. Treat repeatedly with
ness, Treat the resi- aleohol, filtering each instal-
dune with hot water, ment.
and filter;
Residue,— Filtrate.—May
NaCl; con- | contain LiCl.
firm by | Apply flame-test.
jflarme-test.
Note on Nomenclature.—The operations of evaporation and
heating to redness, commonly termed ignition, are frequently
necessary in analysis, and are usually conducted in the above
manner, If yegetable or animal matter be present also, carbon
is set free, ignition is accompanied by carbonization; the
material is said to char. When all carbonaceous matter is burnt
off (the crucible being slightly inclined and its cover removed to
| ‘combustion), and mineral matter, or ash, alone remains,
the operation of incineration has been effected.
THE METALLIC RADICALS.
Note on the Classification of the Elements. —The compounds of
potassium, sodium, ammonium, and lithium, have many analogies,
The carbonates, phosphates, and other common salts are soluble
in water, except lithium carbonate and phosphate, which are only
sparingly soluble, Atoms of the metallic radicals are univalent
—that is, each displaces or is displaced by one atom of hydrogen,
In fact, these radicals constitute by their similarity in properties a
distinct group or family. All the elements thus naturally fall into
classes—a fact that should constantly be borne in mind, and
evidence of which should always be sought. It would be impos-
sible for the memory to retain the details of Chemistry with-
out a system of classification and leading principles, Classifi-
cation is also an important feature in the art as well as in the
science of Chemistry; for without it practical analysis could not be
undertaken, The classification adopted in this volume is founded
on the quantivalence of the elements (or radicals) and on their
analytical and general relations.
QUESTIONS AND EXERCISES.
Why are ammonium salts classed with those of potassium and sodinm ?
Mention the sourees of the ammonium salts.—Describe the characters
of Ammonium Chloride,—Give the formula of Ammonium Sulphate—
Adduce evidence of the existence of Ammonium.—How is Ammonia
water prepared ?—How is the official Solution of Ammoninm Acetate
prepared ?—What is the composition of commercial Ammonium Carbon-
ate ‘—Define sub/imation.—What ammonium salt is contained in Spiritus
Ammonix Aromaticus, U.S. P.?—Give diagrams or equations illustrating
the formation of Ammonium Citrate (from hydroxide and from earbon-
ate), Phosphate, and Benzoate,—Give the formula of Ammonium Oxa-
late.— How is ammonium hydroxide converted into sulphide ?—Describe
the preparation of Hydrogen Sul)phide.—Enumerate and explain the
tests for ammonium.—How is potassium detected in a solution in which
ammonium has been found ?—Give equations illustrating the action of
sodinm hydroxide on ammonium acetate; potassium hydroxide on
ammonium sulphate: and calcium hydroxide on ammonium nitrate,—
Name the sources and official compounds of lithium.—Explain the forma-
tion of lithium citrate —On what chemical hypothesis are lithium
compounds administered to gouty patients ?—What are the chief tests for
lithium ’—Deseribe the analysis of an aqueous liquid containing salts of
potassium, sodium, ammonium and lithium.,—What meanings are com-
monly assigned to the terms eraperation, ignition, carbonization, and
incineration ’—Write a short article descriptive of the analogies of potas-
sium, sodium, ammonium and lithium and their compounds,
BARIUM, STRONTIUM, CALCIUM, MAGNESIUM.
These four elements have many analogies. Their atoms are
bivalent— Ba", Sr°*, Cav’, Ma-*,
BARIUM.
BARIUM: Ba. Atomic weight, 136.4.
It is the analytical reactions of this metal which are of chief
interest to the student of pharmacy, Barium nitrate, Ba(NO,),,
and chloride, BaCl,,2H,O0 (‘‘ Barium Chloride Test Solution,’’
U. 5. P., contains 1 in 10 of water) are the soluble salts in common
use in analysis, These and other salts are made by dissolving the
native carbonate, BaCO, (the mineral wifherite) in acids, or by
heating the other common natural compound of barium, the sul-
sa (heavy white or heavy spar, BaSO,) with coal, which yields
barium sulphide, BaS (BaSO,+-4C=4C0-+ Bas), and treating this
with appropriate acids. When the nitrate is strongly heated, it
decomposes, yielding barium oxide or baryfa, BaO, By intensely
heating a mixture of barium sulphate and carbon in the electric
furnace, barium oxide mixed with a small proportion of sulphide
is now prepared on a large scale. Barytha, on being moistened,
unites with the elements of water with the evolution of much
heat, and yields barium hydroxide, Ba(OH),. The latter is toler-
ably soluble, giving baryta water; and from this solution crystals
of barium hydroxide, Ba(OH),,8H,O, are obtained on evaporation
Barium hydroxide is largely used in the refining of sugar.
Barium Dioxide, BaO,, is formed in passing air over barium
oxide heated to about 600°C. At a somewhat higher tempera-
ture, Oxygen is evolved and barium oxide remains. This is
Boussingault’s old process; but, after a time, the barium oxide
loses its power of combining with additional oxygen. If the air
be freed from carbonic anhydride, and the dioxide be not exposed
toa much higher temperature than 800°C,, the barium oxide can
be used over and over again, The air is passed over it under in-
ressurc, und gives rise to the formation of the dioxide,
The air is then turned off, and the additional oxygen is given up
again when the pressure is sufficiently reduced by means of air-
ig rogen Diowide,—By the action of a dilute acid, barium
dio yields a solution of Aydrogen dioxide, H,O,, formerly
called oxygenated water, An aqueous solution of hydrogen dioxide
which yields (by the decomposition of the dioxide) ten times its
volume of oxygen, is the official Aqua Hydrogenii Diorvidi, U.S. P.
When this solution is mixed with a sufficiency of diluted sulphuric
acid, and solution of potassium permanganate is added in excess,
the dioxide is completely decomposed, with evoluting oxygen :—
5H,0, + 2KMn0, + 8H,SO0, = 50, +- 8H,O0 + K,SO, + 2Mn80,
One-half of the oxygen comes from the dioxide and one-half from
the permanganate. The dioxide readily yields oxygen to many
and organic substances, |
THE METALLIC RADICALS.
Analytical Reactions of Barium Salts,
1. To the aqueous solution of any soluble barium salt (nitrate or
chloride, for example) add dilute sulphuric acid ; a white precipi-
tate is obtained. Set the test-tube aside for two or three minutes,
and when some of the precipitate has fallen to the bottom, pour
away the supernatant liquid, wash the precipitate by adding water,
shaking, setting aside, and again decanting; and then add moder-
utely concentrated nitric acid, and boil; the precipitate is insol-
uble. The precipitate is at once produced by the addition of a
solution of calcium sulphate or other soluble sulphate.
The production of a white precipitate by sulphuric acid or other
sulphate, insoluble even in hot nitric acid, is highly characteristic
of barium, The precipitate consists of barium sulphate, BaSO,.
2. To a solution of barium salt add solution of potassium chro-
mate, K,CrO,; a pale-yellow precipitate of barium chromate,
BaCrQ),, 1s immediately formed. Add acetic acid to a portion ; it
is insoluble. Add hydrochloric or nitric acid to another portion ;
it dissolves.
Potassium dichromate or anhydrochromate, K,CrO,, CrOQ,, or
K,Cr,O0,, must not be used in this reaction, otherwise the barium
will be only partially precipitated, as the dichromate gives rise to
the formation of free acid, in which barium chromate is to some
extent soluble:—
K,CrO,,CrO, + 2BaCl, + H,O = 2BaCrO, + 2KC1 + 2HCI,
Other Analyticial Reactions,—To a solution of a barium
salt add a solution of a carbonate (ammonium carbonate,
(NH,),CO,, will generally be rather more useful than the
others); a white precipitate of barium carbonate, BaCO,, is
formed. To another portion of the solution add an alkali-
metal phosphate (sodium phosphate, Na,HPO,, is the most
common of these chemically analogous salts, but ammonium
phosphate (NH,),HPO,, is often used in preference); white
barium hydrogen phosphate, Bali PO,, is precipitated, insol-
uble in pure water, but slightly soluble in aqueous solutions
of some salts, and readily soluble even in acetic and other
weak acids. To another portion add ammonium oxalate,
(NH,),C,O,; white barium oxalate, BaC,O,, is precipitated,
soluble in dilute mineral acids, and sparingly so in acetic
acid. Barium salts, moistened with hydrochloric acid, impart
a greenish color to 1 Bunsen flame or spirit-lamp flame.
Memorandum.—Good practice will be found in writing out
equations to represent each of the foregoing reactions,
Antidotes, —[n causes of poisoning by soluble barium salts, obvious
STRONTIUM, lll
antidotes would be solution of alum or of such sulphates as those
of magnesium (Epsom salt) and sodium (Glauber’s salt).
QUESTIONS AND EXERCISES,
What is the valency of barium ’—Write the formulz of barinm oxide,
hydroxide, chloride, nitrate and sulphate; and state how the substances
are prepared.—Describe the preparation of hydrogen peroxide,—Which
of the tests for barium are must characteristic ?—Give equations for the
rvactions.—Name the antidote in cases of poisoning by soluble barium
sults and explain its action.
STRONTIUM: Sr. Atomic weight, 86.94,
Occurrence. —Strontium compounds are not abundant in nature;
yet the carbonate, SrCO,, known as strontianite, and the sulphate,
Brs0,, known as celestine (from ca/um, the sky, in allusion to its
occasional bluish color), are by no means rare minerals,
Salts of Strontium are occasionally employed in medicine, the
following being official in the United States Pharmacopoia:—
Strontii Bromidum, SrBr,,611,0; Stronfii Lodidum, Srl,,6H,0;
Strontit Salicylas, Sr(C,H,O,),2H,0. The compounds of this
metal are, however, chiefly used by firework manufacturers in
preparing ‘red fire.”’ Strontium hydroxide, like barium hy-
droxide, is much used in sugar-refining. Strontium salts impart
a crimson color to the flame. Strontium nitrate, Sr(NO,),, is the
most suitable strontium salt to use in making pyrotechnic mixtures,
its oxygen causing vigorous combustion when the salt is mixed
with charcoal, sulphur, etc., and heated. This salt may be
obtained by dissolving the carbonate in nitric acid; a method
which is appropriate for the preparation of other strontium salts
if the corresponding acids are employed. Strontium salts may
also be prepared from the cheaper strontium sulphate, Sr8O,, by
strongly Gedting this with carbon to convert it into sulphide, Srs,
and then dissolving the latter in the appropriate acids. Strontium
sulphate is very sparingly soluble in water.
Analytical Reactions of Strontium Salta,
1. To a solution of strontium nitrate or chloride add
immonium carbonate; a white precipitate of strontium car-
bonate, SrCO,, is produced. | 7
2. To a solution of a strontium salt add highly dilute sul-
phuric acid, or an equally dilute solution of any sulphate
(that of calcium, for example); a white precipitate of strontium
sulphate, Srdo,, is produced. The formation of this precipi-
112 THE METALLIC RADICALS.
tate is promoted by stirring and by setting the liquid aside
for some time, (Barium salts give an immediate precipitate
under similar circumstances. )
3. To a dilute solution of a strontium salt add potassium
chromate ; no precipitate is produced unless the mixture is
allowed to stand for some time, or is boiled.
Barium may be separated from the strontium by means of
potassium chromate, this reagent at once precipitating barium
from aqueous or acetic acid solutions. The value of the reaction
is enchanced if acetic acid or ammonium acetate be present, stron-
tium chromate being far more soluble in such fluids than in water
(Ransom). It is also more soluble in cold than in hot solutions,
4. Moisten the end of a platinum wire with a solution of a
strontium salt and hold it in the Bunsen flame; a crimson
color is imparted to the flame.
Other Analytical Reactions.—A|kali-metal phosphates and
oxalates give white insoluble precipitates with strontium salts
as with barium (and also with calcium ) salts.
CALCIUM: Ca. Atomic weight, 39.8.
Oceurrence, ete. —Calcium compounds form a large proportion
of the crust of our earth, Calcium carbonate is met with as chalk,
marble, limestone, cale-spar, etc. ; the sulphate as gypsum and
alabaster; the silicate in many ninneal caleium fluoride as fluor-
spar. The phosphate is also a common mineral, Plaster- of-Paris,
(Caleii Sulphas Ersiccatus, 0. 8. P.), is gypsum from which the
water of crystallization has been driven away by heating to a
temperature of dull redness, The element itself is only isolated
with great difficulty. Its melting point is 760° C.; its sp. gr.
L85at16.5°C. ,
Calcium Chloride.
Experiment 1, Tosome hydrochloric acid add calcium car-
bonate (Chalk, or the purer form, white marble), CaOO,
until effervescence ceases ; filter ; solution of calcium chloride,
CaCl,, a common soluble calcium salt is formed.
CaCo, + 2HCI = CaCl, + HO + OQ,
Calcium Hydrochloric Cale ium Water Carbonic
cnrbonate acid chloride anhydride
This solution may be obtained quite neutral by well boiling
before filtering off the excess of marble,
Solution of calcium chloride evaporated to a syrupy consistence
CALCIUM. 115
yields crystals (CaCl,,6H,O). These are extremely deliquescent.
The solution, evaporated to dryness, and the white residue heated
to about 392° F. (200° C.), gives solid calcium chloride, CaCl,
2H.0, in a porous form. The resulting lumps are used for drying
guses and for freeing certain liquids from water. By fusion at a
low red heat the anhydrous chloride CaCl,, (Caleii Chloridum,
U. 8. P.), is produced. Calcium chloride is soluble in alcohol.
Marble often contains ferrous carbonate, FeCO,, which im
the above process becomes converted into ferrous chloride,
rendering the calcium impure :—
FeCO, + 2HCl = FeCl, + H,O + ©O,
Perrous Hydrochloric Ferrous Water Carbonic «
carbonate acld chloride anhydride
If pure calcium chloride he required, a few drops of the
solution should be poured into a test-tube or beaker, diluted
with water, and examined for iron (by adding ammonium
hydrosulphide, which gives a black precipitate with iron
salts), and if the latter is present, calclum hypochlorite (in
the form of chlorinated lime) and slaked lime should be added
to the remainder of the liquid, and the whole boiled for a
few minutes. The iron is precipitated as ferric hydroxide,
and is filtered off :—
4FeCl, + Ca(ClO), + 4Ca(OH), + 2H, = 4Fe(OH), + 5CuCl,
Ferrous Calcium Calcium Water Ferric Calcium
ehloride hypochlorite hydroxide hydroxide chloride
The solution of calcium chloride so obtained may contain
some calcium chlorate, On adding excess of ammonium car-
bonate and heating gently, then washing the precipitate
thoroughly with hot water (see p. 114) and redissolying it
in hydrochloric acid, a pure solution of calcium chloride may
be obtained,
This process may be imitated on the small scale after
adding « minute piece of iron to a fragment of the marble
before dissolving in acid. ,
Calcium bromide, ( Caleii Bromidum, U. 8. P.), is also
official. |
Calcium Oxide, Quicklime. Caustic Lime.
_ Experiment 2.—[’lace « smal! piece of chalk in a strong
fire or furnace, and heat until a fragment, chipped off and
cooled, does not effervesce on the addition of acid; lime, CaO,
( Calz, U. 8. P.), remains.
5
THE METALLIC RADICALS.
CaCQ, = CaO + #£CO,
Calcium Calcium Carbonic
carbonate (chalk) oxide (lime) anhydride
Lime-kilns.—On a large scale the above operation is carried
on in what are termed fime-filns (kiln, Saxon, cyln, from cytene,
a furnace),
Calcium Hydroxide. Slaked Lime.
Experiment 3. —When the quicklime prepared in the pre-
ceding experiment is cold, add to it about half its weight of
water, and notice the evolution of steam and the. other
evidence of energetic chemical action; the product is slaked
lime, calcium hydroxide, Ca(OH), with whatever slight
natural impurities the lime may contain, Theslaking of hard
or “stony” lime may be accelerated by using hot water.
Cao + HO = OwOB),
Lime Water Calcium hydroxide
Lime-Water—P lace the calcium hydroxide (washed with
a little water to remove traces of soluble salts) in about a
hundred times its weight of water, and shake frequently;
in a short time a satured solution, known as /ime-water,
(Liquor Calcis, U. 5S. P.), results. It contains about 15
grains of calcium hydroxide, Ca(OH),, equivalent to about
10 grains of lime, (CaO), in one point at 60° F. (15.5° C.).
At higher temperatures less is dissolved.
Saccharated Solution of Lime.—Slaked lime is much more
soluble in aqueous solution oi sugar than in pure water. Syrup
of lime, (Syrupus Calcis, U.S. P.), is such a solution, It is a
more efficient precipitant of hydroxides, carbonates, and plios-
phates than lime-water.
Solutions of calcium hydroxide absorb carbonic anhydride on
exposure to air, a semi-crystalline precipitate of calcinm carbon-
ate being deposited. When the saccharated solution is heated,
there is precipitated a compound consisting of three molecules of
lime with one of sugar, When it is freely exposed to air, oxy-
gen is absorbed, and the solution becomes colored.
Calcium Carbonate.
Experiment 4.—T'o a solution of calcium chloride add excess
of sodium carbonate, or about 13 parts of the carbonate to §
of the anhydrous chloride ; a white precipitate of calerum car-
hbonate, CaC O,, ( Caleti Carbonas Preeiyitatua, U. S. PL), is
CALCIUM. 115
produced. If the solution of the salts be heated before admix-
ture, and the whole be set aside for a short time, the particles
assume a finely granular or slightly crystalline character to
a greater extent than when cold water is used.
CaCl, + NaCO, = CaCO, + 2NaCl
Calcium Sodium Calcium Sodium
chloride carbonate carbonate chloride
Collect and purify this so-called Precipitated Calcium Car-
bonate, by pouring the mixture into a filter-paper supported by
a funnel, and when the liquid has passed through the filter,
ur water over the precipitate three or four times, until the
whole of the sodium chloride is washed away. This operation
is termed washing a precipitate. When dried by aid of a
water-bath (p. 118) or other means, the precipitate is ready for
use. It is not only somewhat purer than the average samples
“~sal chalk or “prepared chalk” (see p. 117), but it is
- ~wegate, and on account of its physical charac-
Lo “4a constituent of dentifrices,
’ (from 6ib0, I drink), is simply
’ the best white rags—white blot-
- .y good quality. Students’ or ana-
“ect precipitates, are circular pieces
from three to six inches in diameter,
Fia. 24.
Construction of paper filters.
twice folded (6, c), and then opened out so as to form a hollow
cone (d). The cone is supported by a glass or earthenware fun-
nel. Square pieces of filter-paper should be rounded by scissors
after twice folding. If this is not done, angular portions of the
paper project above the liquid in the filter, and if a spirituous or
other volatile liquid is being passed through such a paper, much
of the liquid will be wasted by evaporation from the unnecessurily
large surface exposed.
Paper filters of large size are apt to break at the point of the
cone. This may be prevented, and the rate of filtration much
accelerated, by supporting the paper cone in a cone of muslin.
116 THE METALLIC RADICALS.
Wash-bottle.—Precipitates are best washed by means of a fine
jet of water directed on to the different parts of the filter, A
common narrow-necked bottle, of about half-pint capacity, is
fitted with a cork; two holes are bored through
Fig, 25. the cork, the one fora glass tube which reaches
: to the bottom of the bottle and is bent exter-
nally to a slight acute angle, the other for a
tube bent to a slightly obtuse angle, the inner
arm terminating just inside the bottle. The
outer arms may be about three inches in length,
The extremity of the outer arm of the longer
tube should be previously drawn out to a fine
capillary opening by holding the original tube
(before bending) in a flame, and, when soft,
slowly pulling the two ends apart from each
other until the softened portion is reduced to
the diameter of a knitting-needle. The tube
is now cut at the narrow part by means of a file, and the sharp
edge rounded off by placing it in a flame for a second or two.
The outer extremity of the shorter tube should also be rounded
off in the flame. The apparatus being put together and the bottle
nearly filled with water, air from the lungs, blown through the
short tube, forces water out in a fine stream at the capillary orifice.
For a hot-water wash-bottle (Fig. 25) the tubes and cork are fitted
toa flask which may be heated over a Bunsen burner or on a
water-bath (p. 118). Fine twine wound closely around the neck of
the flask forms a suitable non-conducting protection for the hand
of the operator.
Hot-water wash-
bottle,
Decantation. Decantation, Siphon in action,
Decantation.—Precipitates may also be washed by allowing
them to settle, pouring off the supernatant liquid (Fig. 26) agitating
with water, again allowing to settle, and soon. This is washing
ai
CALCIUM. 117
by decantation (de, Bara canthus, an edge). If the stream of
liquid exhibits any tendency to run down the outer side of the
vessel during decantation, it should be guided by a glass rod
placed against the point where the stream emerges (Fig. 27).
If the vessel be too large to handle with convenience, the liquid
may be drawn off by means of a siphon, as shown in Fig. 28.
Prepared chalk, (Crata Preparata, U. 8. P.), is merely washed
chalk or whiting, but in pharmacy, fashion demands that the chalk
be in little conical lumps, about the size of thimbles, instead of
af the larger rolls characteristic of whiting. Its powder is amor-
phous.
If either the precipitated calcium carbonate, or the prepared
chalk, contains alumina, magnesium salts, iron oxide, or phos-
phates, its solution in acid, evaporated to dryness, and redissolved
in water, will yield a precipitate of hydroxides or phosphates on
the addition of syrup of lime,
Calcium Phosphate.
Experiment 5.—Digest bone-ash (bones burnt m an open
crucible with free access of air until all animal and carbo-
naceous matter has been removed, and a residue of impure
calcium phosphate is left), with twice its weight of hydro-
chlorie acid (diluted with four times its volume of water) in
a test-tube or larger vessel; the phosphate is dissolved.
‘caletun™ +* 4HCl = CaH,HO,), + 2CaCl,
Calclum Hydrochloric Acid eale ium Calcium
acid phosphate chloride
nade ve solution with water, boil, filter, and when cold,
add excess of ammonia solution ; the calcium phosphate, now
practically pure, ( Caleii Phosphas Precipitatus, U. 8, P.), is
ipitated as a light white amorphous powder. After
well washing, the precipitate should be dried over a water-
bath (see p. 118), or at a temperature not exceeding 212° F,
(100° Cy to prevent undue aggregation of the particles.
penal 4+ 2CaCl, + 4NH, = Ca,(PO,), + 4NH,C!
um Caicium Ammonia Calcium Ammonium
hloride phosphate ehloride
aan or bone-earth contains small quantities of calcium car-
bonate and sulphide, These are decomposed in the above process
the acid, calcium chloride being formed; on boiling the mix-
ture, carbonic anhydride and hydrogen sulphide areevolved. Any
of siliceous matter, etc., is removed by filtration.
In bones, the calcium phosphate is always aceompanie d by a small
quantity of an allied substance, magnesium phosphate, which is
THE METALLIC RADICALS.
not removed by the process described above. Bone-ash also con-
tains a trace of calcium fluoride, CaF,
Jalcium phosphate is generally prepared by the interaction of
calcium chloride, sodium phosphate, and ammonia, the resulting
precipitate being washed with cold water.
Calcium Hypophosphite, ( Caleti hc atti . & Bye
official.
A Water-bath for the evaporation of liquids or ‘tow drying moist
solidsat a temperature below 212° F. (100° C.), is an iron, tin, or
earthenware pan, the mouth of which can be narrowed by iron or
tin diaphragms of various sizes, 80 as to adapt it to the diameters
of basins or plates. (See Fig. 18, p. 76). In the British Pharma-
copwia, ‘when a water-bath is directed to be used, it is to be
understood that this term refers to an apparatus by means of which
water or its vapor, at a temperature not exceeding 212° F,
(100° C.), is applied to the outer surface of a vessel containing
the substance to be heated, which substance may thus be sub-
jected to a heat near to, but necessarily below, that of 212° F,
(100° C.),”’ Evaporation in vacuo is performed by simply placing
the vessel of liquid over, or by the side of, a small vessel contain-
ing concentrated sulphuric acid or other absorbent of moisture, on
the plate of an air-pump, covering with a capacious glass hood or
‘7
“‘receiver,’’ and exhausting.
Sodium Phosphate.—Ordinary sodium phosphate, Na,HPO,,
12H,0, (Sodit Phesphas, U.S. P.), is prepared from calcium
phosphate as follows :—Mix in a mortar, 3 ounces of ground
bone-earth with 1 fluidounce of sulphuric acid; set aside for
twenty-four hours to allow the interaction to take place; add
about 3 ounces of water and put in a warm place for two
days, a little warm water being added to make up for that
lost hy evaporation; stir in another 3 ounces of water, warm
the whole for a short time, filter, and wash the residual cal-
cium sulphate on the filter in order to remove adhenng acid
calcium phosphate; concentrate the filtrate (1. e., the liquid
which has passed through the filter), to about 3 ounces, and
filter again if necessary. To the hot solution, which con-
tains acid calcium phosphate, add solution of sodium earbon-
ate (preparated from about 4) ounces of the crystallized salt)
until a precipitate (calcium hydrogen phosphate, CaHPO,) no
longer forms, and the liquid is faintly alkaline ; filter, evapo-
rate, and set aside to crystallize. The following eq uations show
the two decompositions which occur during the operations :—
Ca(PO,), -+ 2H,50, = CaH/(PO,), + 2CaS0,
Calelum Sulphuric Acid falcium Calcinm
phoaphate acid phosphate sulphate
CALCIUM, ; 119
feta calcnte + odin? — Ne, HPO, + H,O + CO, + CaHPoO,
Acid calcium Bod Water Carbonic Calcium
hos phate Sieenbaie anhydride a vanhan:
Sodium phosphate crystallizes in transparent colorless monoclinic
prisms, efflorescent, having an alkaline reaction and a saline taste.
One part in ten of water constitutes ‘Sodium Phosphate Test
Solution,’? U. 8, P. The crystals effloresce rapidly in the air
until nearly half the water has escaped, and a salt is obtained
which has a permanent composition represented by the formula,
Na,HPO, 7H,O. Another sodium phosphate (sodium dihydrogen
phosphate), Nall,PO, H, ©, is obtained by mixing solutions of -
phosphoric acid and sodium carbonate in the right proportions,
evaporating the mixed solution and setting it aside to crystallize.
Calcium Hypochlorite.
Experiment 6.—Pass chlorine, generated from black man-
ganese oxide and hydrochloric acid, as already described,
over damped slaked lime contained in a piece of wide tubing,
outlet end of which is connected with a tube leading into a
fume-cupboard. The product Chlorinated Lime, ( Calx
Chiorinata, U. 8. P.), is ordinary bleaching-powder, a com-
tos of calcium h hlorite and chloride, mixed with a
rice “3 a weceage) i hydroxide, It is commonly,
perly, called chloride of lime, and is one of the
ares of known disinfectants.
in, + 4HCL = MnCl, + 2H,0 + Cl,
Bisck man- vs ha pa Man nous Water Chlorine
ganese acid chloride
2000), + 20 = 2H,0 + CaCl0,, CaCl,
a) Chlorine Calcium Calelum
hypochlorite chloride
Chlorinated lime exposed to air and moisture, as in disinfecting
the atmosphere of sick-rooms, slowly yields hypochlorus acid,
HCIO, calcium calcium carbonate being formed at the same time. Free
acid soon breaks up into water, chloric acid, HCIO,,
free chlorine. Chloric acid is also unstable, decomposing
oxygen, chlorine, water and perchloric acid, HCIO,. The
quantity of hypochlorus acid diffused through an apartment
ose + is exposed, thus yields fourteen-fifteenths
of its chlorine in the form of chlorine gas.
Sonal bleaching- ér.—Treated with alcohol, bleach-
r-pow ed not viel its calcium chloride to the solvent;
er is nota mere mixture of calcium chloride and
sochlorite : water, also does not dissolve out first one salt and
nm
120 THE METALLIC RADICALS.
then the other, but together, in the molecular proportions of the
formula, p. 119, On the other hand, when the aqueous solution
is cooled, or evaporated in vaecwo, crystals are obtained which
Kingzett has shown to be nearly pure calcium hypochlorite, the
solution containing calcium chloride, While the former fact
indicates that the powder is a compound and not a mere mixture,
the latter indicates that it is a feeble compound—an adhesion of
molecules of hypochlorite and chloride, as shown in the equation,
rather than any closer or more intimate combination of atoms.
If it be regarded as a single rather than a double salt, then
the following formula (Odling) may be employed, CaOCl, or
. (Cl
Ca clo
Bleaching-liquor.— Digest chlorinated lime in water, in
which the bleaching compound is soluble. Filter from un-
dissolved lime, etc., and test the bleaching powers of the clear
liquid by adding a few drops to a decoction of logwood
slightly acidulated.
Experiment 7.—Mix a little powdered wood chareoal with
three or four times its weight of gypsum, and heat to redness
inacrucible. Some of the calcium sulphate is reduced to
sulphide, CaS, with production of carbonic anhydride and car-
bonie oxide. If the product contains not less than 60 per-
cent. of calcium sulphide, it is the official Sulphurated Lime
(Calz Sulphwrata, U.S. P-.).
Official test. —If 1 Gm, be mixed with a cold solution of 2.08
Gm. of cupric sulphate in 50 cubic centimetres of water, and,
after the addition of a little hydrochloric acid, the mixture be well
stirred and heated on a water-bath until all action has ceased and
then filtered, the filtrate should give no color on addition of ex-
cess of ammonia water (presence of at least 60 percent. of pure
calcium sulphide).
The explanation of the mode of this test is as follows :—Cupric
sulphate and calcium sulphide interact in the presence of the acid,
giving insoluble cupric sulphide and calcium sulphate, thus :—
CuSO,+-Ca8=Cu8 + CaS0,.
On adding up the atomic weights or the constituent elements
of crystallized cupric sulphate, 247.85 will be found to be the
formula weight ; while CaS will similarly represent 71.53 parts,
As 247.85 is to 71.63, s0 (approximate ly) is l4to4. But only
half of the sulphurated lime is calcium sulphide ; therefore 8 grains
of such sulphurated lime will interact with 14 of cupric sulphate.
If the 8 grains are below the stated strength, then they will not
attack the whole of the 14 grains of cupric salt, and, in that
ammonia water (or potassium ferrocyanide) will reveal copper in
the filtered liquid.
CALCIUM, 121
Calcium Gummate,
Calcium Gummate is the only official calcium salt that remains
to be noticed. This compound is, in short, arabin, the ordinary
Gum Acacia or Gum Arabic (Acacia, U. 8. P.). A solution of
gum arabic in water yields a white precipitate of calcium oxalate
on the addition of solution of ammonium oxalate; or a piece of
gum incinerated in a porcelain crucible yields a calcareous residue,
which, when dissolved in a dilute acid, affords characteristic
reactions with any of the analytical tests for calcium salts, de-
seribed further on. In some specimens of gum arabic a portion of
the calcium is displaced by an equivalent quantity of potassium or
magnesium, The gummic or arabic radical may be precipitated
as opaque gelatinous lead gummate by the addition of a solution of
lead subacetate to an aqueous solution of gum. These statements
should be verified by experiment. Mucilago Acacia, U. 8. P.,»is
a solution of acacia in water and lime water.
Tragacanth ( Tragacantha, U. 8. P.), is a mixture of soluble
arabinoid gum and a variety of calcium gum, insoluble in water,
termed bassorin. With water and glycerin a gelatinous mucilage
is formed (Mucilago Tragacantha, U, 8. P.).
Calcium Carbide.
Calcium carbide is of interest chiefly on account of the easy
method of preparing acetylene which its interaction with ~
water affords, It may be obtained by subjecting an intimate
mixture of calcium oxide and carbon to the exceedingly high
temperature of the electric furnace. The carbide has the
composition CaC,, and is usually met with as a fused homo-
geneous black mass, although when quite pure it is colorless
and transparent. Water rapidly decomposes it, with the evo-
lution of almost perfectly pure acetylene. Dilute acids behave
in the same way as water ; concentrated nitric and sulphuric
acids attack it but slightly.
Analytical Reaction of Caleium Salts.
1. Add dilute suphuric acid to a solution of a calcium salt
contained in a test-Lube or small test-glass; a precipitate of
calcium sulphate, CaSO,, is formed if the solution is not too
dilute. The calcium is not completely prec ipitated as sulphate,
because this salt, unlike barium sulphate, is quite appreciably
soluble in water. The addition of solution of calcium sulphate
to a solution of another calcium salt does not produce a preci ipi-
tate even on standing for some time or on boiling. (Ce ‘ompare
the behavior of barium and of strontium sa ts).
122 THE METALLIC RADICALS.
Solution of Calcium Sulphate.—The official Calcium Sulphate
Test Solution, U. 8, P., isa saturated solution and contains one
part of calcium sulphate in 875 parts of water,
2. Add potassium chromate, K,CrO,, to a solution of a
calcium salt slightly acidified with acetic acid; no precipitate
is produced even on standing or on boiling. (Compare the
behavior of barium and strontium salts. )
These two reactions are most valuable in analysis, as every pre-
cipitant of calcium is also a precipitant of barium and of strontium;
but in dilute solutions, calcium sulphate and (in presence of acetic
acid), potassium chromate are precipitants of barium only,
Other Analytical Reactions.—To separate portions of a
solution of a calcium salt, add ammonium carbonate, sodium
phosphate and ammonium oxalate. Precipitates are obtained
which correspond in appearance to those produced in the case
of a solution of a barium salt; their composition is also
analogous, hence their correct formule can easily be deduced
and equations written to represent the actions which take
place, Of the precipitants just mentioned, ammonium oxalate
is the one most commonly used as a reagent for calcium salts
in the ahsence of barium. Calcium oxalate is insoluble in
acetic, but soluble in hydrochloric or nitric acids. Calcium
compounds impart a reddish color to the Bunsen flame,
QUESTIONS AND EXERCISES.
Write a paragraph on strontium, its natural compounds, chemical re-
lations, technical applications and tests.—Enumerate some of the com-
mon natural compounds of calcium.—Represent by an equation the ac-
tion of hydrochloric acid on marble.—Why is calcium chloride used as a
desiccating agent for gases?—How would you purify Calcium Chloride
which has been made from ferruginous marble ’—Give diagrams,—Write
a few lines on chemistry of the lime-kiln.—What occurs when lime is
“slaked ’’?—To what extent is lime soluble in water (Liquer Caleis,
U.S, P.); and in Syrup (Syrupus Caleis, U.S. P.)?—Describe the preparation
of the official Precipitated Calcium Carbonate (Calcii Carbonas Preveipi-
fafus, U. 8. P.); how does it differ from Prepared Chalk (Creta Preeparata,
U. 8. P.)?—How does filter-paper differ from other kinds of paper?}—Ex-
plain the construction of a “ wash-bottle.’— Define decantation.—State the
difference between bone-ash and (ulcii Phosphas Pracipitatus.—How is
“bone-earth ” purified for use in medicine ?—Give equations showing the
conversion of Calcium Phosphate into Sodinm Phosphate.—Write n short
article on the manufacture composition, and uses of “ bleaching-powder”
(Cale Chlorinata, U. S. P.\—How may calcium be detected in Gum
Arabic ?—State the chemical natore of Tragacanth.—To what extent is
calcium solphate soluble in water ?—Barium being absent, what reagents
may be ueed for the detection of calcium ?—Which is the chief test?
MAGNESIUM. ~ 123
MAGNESIUM: Mg. Atomic Weight, 24.18.
Occurrence, ete.—Magnesium is abundant in nature in the form
of magnesian or mountain limestone, termed dolomite (after Dolo-
mieu, a geologist), a double magnesium and calcium carbonate,
in very common use as a building-stone, and magnesite, a toler-
ably pure magnesium carbonate, though too ‘‘stony’’ for direct
use in medicine, even if very finely powdered. Magnesium chlo-
ise bp magnesium sulphate (Epsom salt) occur in the water of
and magnesium salts also occur in sea water and
impart to it its bitter taste. A hydrous sulphate, MgSO,,H,0,
termed ‘ieserife, occurs near Stassfurt, in Prussia. Metallic mag-
nesium may be obtained from the chloride by strongly heating it
with sodium. The metal burns readily in the air, emitting a daz-
zling light due to the white heat to which the resulting particles
of magnesia, MgO, are raised. The chloride to be employed as
a source of the metal is obtained by dissolving the carbonate in
hydrochloric acid, adding ammonium chloride, evaporating to dry-
ness, ates, De e residue in a deep vessel (on the small seale, a
or flask), until the ammonium chloride is all volatil-
and the magnesium chloride remains as a clear fused liquid.
The latter is poured upon a clean earthenware slab. The ammo-
nium chloride isadded in order to prevent the interaction of mag-
nesium chloride and water which would otherwise take place in
the last stages of the operation, with formation of magnesium
oxide (or oxychloride) and hydrochloric acid.
Magnesium Sulphate.
Experiment 1.—To a few drops of dilute sulphuric acid in a
test-tube, add excess of powdered native magnesium car-
honate, magnesite, MgCO,, and boil until effervescence ceases
and the carbonic anhydride has heen completely expelled.
The filtered liquid is a solution of magnesium sulphate,
erystals of which, Epsom salt, MgSO, TH,O ( Magnesii
Sulphas, U. 8. P.), may be obtained on boiling off most of
the water, and setting the concentrated solution aside to cool.
‘This is an ordinary manufacturing process. Instead of mag-
riage! dolomite may be employed, any iron being remoyed |
ne we solution to dryness (after filtering from
calcium su fettierk miphate produced ), gently igniting to decompose
ferrous sulphate, dissolving in water, filtering from ferric
oxide, and crystallizing. If neither mineral be at hand, the
t may use a little of the ordinary magnesium c ‘arhonate
a,
HS50, = MgSO, + H,O + CO,
Sulphuric Magnesium Water . Carbonic
acid sulphate anhydride
124 THE METALLIC RADICALS,
Magnesium sulphate crystallizes in large colorless, transparent,
rhombic prisms; but, from concentrated solutions, the crystals are
deposited in short, thin needles, a form more convenient for
manipulation, solution, and general use in medicine, The crystal-
lized salt loses 6H,O when heated to 300° F, (about 150°C),
Iron may be detected in magnesium sulphate by adding a solu-
tion of chlorinated lime or chlorinated soda to an aqueous solution
of the salt ; brown ferric hydroxide, Fe(OH),, is then precipitated.
Ammonium hydrosulphide will also give a black precipitate if
iron be present.
Effervescent Magnesium Sulphate (Magnesii Sulphas Effervescens,
U.S. P.), is magnesium sulphate dried on a water-bath until it
no longer loses weight, and then mixed with citric and tartaric
acids and sodium bicarbonate, and granulated,
Magnesium Carbonates.
Experiment 2.—To solution of magnesium sulphate add
solution of sodium carbonate and boil; the resulting precipi-
tate is magnesium carbonate ( Magnesii Carbonas, U.S. P.),
a white, partly amorphous, partly minutely crystalline mag-
nesium hydroxycarbonate, approximately 4MgC 10,, Mg(OH),,
5H,O. A denser, slightly granular precipitate of similar
chemical composition is obtained by mixing concentrated
solutions of the above salts, evaporating to dryness, then
removing the sodium sulphate by digesting the residue in hot
water, filtering, washing, and drying the precipitate.
5MuSO, + 5Na,CO; + 6H,O—4MgCOs,Mg(OH),,5H,0+ 5Na,S0, +00
Magnesium Sodinm Water Officin)] magnesium Sodi jum Carbonic
sulphate carbonate carbonate sulphate anhydride
The proportions for the preparation of the carbonate are 10
parts of magnesium sulphate and 5} of monohydrated sodium car-
bonate, each dissolved in 80 of cold water, the solutions mixed,
boiled for 15 minutes, the precipitate collected on a filter, well
washed, drained, and dried at a temperature not exceeding 2 12°F,
(100° C.). The heavier carbonate is made with the same propor-
tionates of salt, each dissolved in 20 parts instead of 80 of water,
the mixture evaporated quite to dryness, and the residue digested
in water and washed until all sodium sulphate is removed (until
a white precipitate of barium sulphate is no longer formed on the
addition of solution of barium chloride or nitrate to a little of
the filtrate).
Another Process ( Pattinson’ »).—Considerable Ere ing of mag-
nesium carbonate are prepared by treating dolomite (p. 123) with
carbonic anhydride under pressure. The magnesium carbonate
dissolves before the calcium carbonate, and is then precipitated
MAGNESIUM.
from the clear solution by treatment with steam. (Compare next
experiment. )
Experiment 3.—Pass carbonic anhydride, generated as des-
cribed on p. 76, into a mixture of water and magnesium car-
bonate contained in a test-tube. After some time, separate
any undissolyed carbonate by filteration; the filtrate contains
magnesium carbonate dissolved in carbonic acid. A solution
containing about 10 grains of official carbonate in one ounce,
is known as “ Fluid Magnesia,”
The solution is made from freshly prepared carbonate. The
latter is obtained by adding a hot solution of 2 ounces of mag-
nesium sulphate in a half a pint of water to one of 1} ounces of
monohydrated sodium carbonate in another half-pint of water,
boiling the mixture for a short time (to complete decomposition),
filtering, thoroughly washing the precipitate, placing the latter
in 1 pint of distilled water, and transmitting carbonic anhydride
through the liquid (say, at the rate of three or bubbles per second),
for an hour or two, leaving the solution in contact with the gas
under pressure of about three atmospheres for twenty-four hours,
and, finally, decanting from undissolved carbonate; then, after
passing in a little more gas, keeping in a well-closed bottle.
Slight pressure is best produced by placing the carbonate and
water in a bottle fitted with a cork and tubes as for a wash-bottle
(p. 116), conveying the gas by the tube which reaches to the
bottom, and allowing excess of gas to flow out by the upper tube,
the outlet end of which is continued to the bottom of a small
bottle in which mercury, to the depth of about an inch, has been
placed. The bottle should be loosely plugged with cotton wool,
to prevent loss of metal by spurting during the passage of the gas
through it. (Each inch in depth of mereury through which the
gus escapes corresponds to about half a pound pressure on every
square inch of surface within the apparatus. )
Heat a portion of the solution: hydrous magnesium carbonate,
MgCO,, 3H,0, is precipitated. <A salt having the same composi-
tion is deposited in crystals by the spontaneous evaporation of the
solution. On exposure to cold, the solution sometimes affords
large thick crystals (MgCO,,5H,O), which, in the air, lose water,
become opaque, and then have the composition of those deposited
by evaporation, (MgCQ,, 3H,0),.
Magnesium Oxide. Magnesia.
Experiment 4.—Heat magnesium carbonate in a porcelain
eriuicible over a lamp (or in a larger earthen crucible in a fur-
mace) till it ceases to effervesce on adding a dilute acid to a
126 THE METALLIC RADICALS.
small portion ; the residue 1s magnesia, MgO ( Magnesit Ozi-
dum, U.S. P.). The same operation on the heavy carbonate
yields heavy magnesia, MgO (Magnesii Oxridum Ponderosum,
U.S. P.). Both are sometimes called calcined magnesia. A
given weight of the official magnesia occupies three and one-half
times the bulk of the same weight of heavy magnesia.
4MgCO,, Mg(OH),, 5H,O0 = 5MgO + 6H,O + 4CO,
Official magnesium Magnesium Water Carbonic
carbonate oxide anbydride
Magnesium oxide becomes hydroxide in water, slowly at
60° F., rapidly at 212° F. A trace only of hydroxide is dis-
solved. Moisten some magnesia with water, and place the
paste on red litmus-paper; the wet spot, after a time, becomes
blue, showing that the hydroxide is slightly soluble. The
oxide is liable to become hydroxy-carbonate on exposure to
moist air.
The official solution of Magnesium Citrate (Liquor Magqnesii
Citratts) is made by dissolving magnesium carbonate in solution
of citric acid, adding the filtered solution to syrup of citric acid,
contained in an aérated water-bottle, diluting, adding potassium
bicarbonate, stoppering the bottle, and shaking occasionally until
the potassium bicarbonate is dissolved. The formula magnesium
citrate deposited from solution is Mg,(C,H,O,),, 14H,O.
Analytical Reactions of Magnesium Salts.
1. Add solution of ammonia or of ammonium carbonate to
a solution of a magnesium salt (sulphate, for example), and
warm the mixture iu a test-tube; the precipitation of part
only of the magnesium (as hydroxide, Mg(OH ),, or carbonate,
MgCoO,) occurs. Add now to a small portion of the mixture
of precipitate and liquid a considerable excess of solution of
ammonium chloride; the precipitate is dissolved.
It is very necessary to note the solubility of magnesium hydroxide
and carbonate in solution of ammonium chloride, as important
analytical separations of magnesium from other metallic radicals
depend upon it. In analytical practice, the ammonium chloride
should be added before the ammonia or the ammonium carbonate,
as it ix often easier to prevent precipitation than to redissolve a
precipitate once formed.
2. To some of the solution obtained in’ the preceding reac-
tion, add solution of sodium or ammonium phosphate; a white
granular precipitate of ammonium magnesium phosphate,
NH Mg?PO,, 3s produced.
QUALITATIVE ANALYSIS. 127
3. To another portion of the same solution add ammonium
arsenate; a white precipitate of ammonium magnesium arsen-
ate, NH MgAsO,, is produced, which is similar in appearance
to the corresponding phosphate.
.Vote.-—Barium, strontium and calcium are also precipitated
by alkali-metal phosphates and arsenates. The other precipitants
of magnesium are also precipitants of barium, strontium and cal-
cium. Hence the analyst always removes any barium, strontium,
or calcium by an alkali-metal carbonate, as above indicated;
sodium phosphate (or ammonium arsenate or phosphate) then
becomes a very delicate test for the presence of magnesium. In
speaking of magnesium tests, the absence of barium, strontium,
and cglcium salts is to be understood.
DIRECTIONS FOR APPLYING THE FOREGOING ANALYTICAL REAC-
TIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION OF A
SALT OF ONE OF THE METALS, BARIUM, STRONTIUM, CAL-
CIUM, MAGNESIUM.
To a portion of the solution add ammonium chloride, ammonia
water (until the liquid, after shaking, smells of ammonia), and
ammonium carbonate.
ie ee ee __—
A white precipitate is produced. Acidulate an- | No precipitate
other portion of the original solution with acetic acid, | is produced. To
and add potassium chromate. ! the same _por-
An immediate No immediate precipitate is | tion add ammo-
yellow precipi- | formed. To another rtion of | iam phosphate.
tate indicates the original solution add calcium A white crystal-
sulphate. | line precipitate
Ba } . _ | produced either
A white pre- {| No precipitate | at once, or on
cipitate,formed | even on stand- | standing for
on standing for | ing or on boil- | some time indi-
some time, or | ing, indicates cates
on boiling, in-
dicates Ca Mg
Sr
Confirm Ba, Sr, or Ca by flame-test.
1 Potassium bichromate must not be used in these operations, or
a portion of the barium will remain in the liquid and be precipitated
along with, or in the place of, the calcium carbonate, (sec p. 110). The
potassium chromate used must not contain carbonate, or calcium will
be precipitated along with, orin the place of, barium. (The absence
of carbonate may be proved by the non-occurrence of effervescence on
the addition of hydrochloric acid to a little of the solution of the chro-
mate, previously made hot in a test-tube.)
THE METALLIC RADICALS.
small portion ; the residue is magnesia, MgO ( Magnesti Oxr-
dum, U. 8. P.). The same operation on the heavy carbonate
yields heavy magnesia, MgO ( Magnesii Oxidum Ponderosum,
U.S. P.). Both are sometimes called calcined magnesia. A
given weight of the official magnesia occupies three and one-half
times the bulk of the same weight of heavy magnesia.
4MgCO,, Mg(OH),, 5H,0 = 5MgO + 6H,0 + 4CO
Official magnesium Magnesium Water Carbonic
carbonate oxide anhydride
Magnesium oxide becomes hydroxide in water, slowly at
60° F., rapidly at 212° F. A trace only of hydroxide is dis-
solved. Moisten some magnesia with water, and place the
paste on red litmus-paper; the wet spot, after a time, becomes
blue, showing that the hydroxide is slightly soluble. The
oxide is liable to become hydroxy-carbonate on exposure to
moist alr.
The official solution of Magnesium Citrate (Liquor Maqnesii
Citratis) is made by dissolving magnesium carbonate in solution
of citric acid, adding the filtered solution to syrup of citric acid,
contained in an aérated water-bottle, diluting, adding potassitum
bicarbonate, stoppering the bottle, and shaking occasionally until
the potassium bicarbonate is dissolved. The formula magnesium
citrate deposited from solution is Mg,(C,H,O,),, 14H,0.
Analytical Reactions of Magnesium Salts,
1. Add solution of ammonia or of ammonium carbonate to
a solution of a magnesium salt (sulphate, for example), and
warm the mixture in a test-tube; the precipitation of part
only of the magnesium (as hydroxide, Mg(OH ),, or carbonate,
MgCoO,) oecurs. Add now to a small portion of the mixture
of precipitate and liquid a considerable excess of solution of
ammonium chloride; the precipitate is dissolved,
It is very necessary to note the solubility of magnesium hydroxide
and carbonate in solution of ammonium chloride, as important
analytical separations of magnesium from other metallic radicals
depend upon it. In analytical practice, the ammonium chloride
should be added before the ammonia or the ammonium carbonate,
as it is often easier to prevent precipitation than to redissolve a
precipitate once formed.
2. To some of the solution obtained in the preceding reac-
tion, add solution of sodium or ammonium phosphate; a white
granular precipitateof ammonium magnesium phosphate,
NH,MgPO,, is produced.
QUALITATIVE ANALYSIS. 127
3. To another portion of the same solution add ammonium
arsenate; a white precipitate of ammonium magnesium arsen-
ate, NH, MyAsO.,, is produced, which is similar in appearance
to the corresponding phosphate.
Note.—Barium, strontium and calcium are also precipitated
by alkuali-metal phosphates and arsenates. The other precipitants
of magnesium are also precipitants of barium, strontium and cal-
cium. Hence the analyst always removes any barium, strontium,
or calcium by an alkali-metal carbonate, as above indicated;
sodium phosphate (or ammonium arsenate or phosphate) then
becomes a very delicate test for the presence of magnesium. In
speaking of magnesium tests, the absence of barium, strontium,
and calcium salts is to be understood.
DIRECTIONS FOR APPLYING THE FOREGOING ANALYTICAL REAC-
TIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION OF A
SALT OF ONE OF THE METALS, BARIUM, STRONTIUM, CAL-
CIUM, MAGNESIUM.
To a portion of the solution add ammonium chloride, ammonia
water (until the liquid, after shaking, smells of ammonia), and
ammonium carbonate.
A white ipitate is produced. Acidulate an- | No precipitate
other portion of the original solution with acetic acid, | is produced, To
and add potassium chromate, ' the same por-
An immediate No immediate precipitate is | on add ammo-
yellow precipi- | fi 1. To another portion of } nium phosphate.
tate indicates the original solution udd caleium . white = haar
sulohste. ine precipitate
Ba . ; y ira produced either
A white pre- No precipitate at once, or on
cipitate,formed | even on stand- | standing for
on standing for Ing or on boil- | some time indi-
some ah or | ing, indicates cates
| on boiling, in- ;
| dicates Ca Mg
Sr
Confirm Ba, Sr, or Ca By flame-test.
—EEE =
‘Potassium bichromate must not be used in these operations, or
@ portion of the barium will remain in the liquid and be precipitated
along with, or in the place of, the calcium carbonate, (sec p. 110). The
im chromate need mist not contain carbonate, or calcium will
be precipitated along with, orin the place of, barium. (The absence
oO baer rere y be proved by the non-oocurrence of effervescence on
: of hydrochloric acid to a Jittle of the solution of the chro-
mate, previously made hot in a test-tube.)
THE METALLIC RADICALS,
TABLE OF SHORT DIRECTIONS FOR APPLYING THE FOREGOING
ANALYTICAL REACTIONS TO THE ANALYSIS OF AN AQUEOUS
SOLUTION OF SALTS CONTAINING ANY OR ALL OF THE
METALLIC RADICALS HITHERTO CONSIDERED,
To a portion of the solution add ammonium chloride, ammonia
water (until the liquid, after shaking, smells of ammonia), and
ammonium carbonate. Warm and filter.
Previpitate. Filtrate,
, BaCO,, SrOO,, CaO0», Add ammonium phosphate,
Dissolve on the filter in dilute nitric | allow to stand for some time,
acid ; evaporate the solution to dryness; and filter.
digest the residue in a mixture of equal , —
volumes of alcohol and ether ; filter. Preeipitate. Filtrate.
Residue. Filtrate. v hite at ont («t) Boil a a
1 ri le talling lion. A white
Ba( NO,), and Si(NO,),. | Contains NH, MgPO, precipitate in-
Wash with mixture of Cai NOs), indicates | dicates Li.
sone and ether, dis _ Expel the | M g Confirm = Li.
solve in water, add | alcohol and | by flametest.
dilute acetic acid, and ether by | (6) Test for K
then K Cr, ; filter. "gently heat- | by oe oy
7a = Ing on a mth thio-sul-
Precipitate, | Filtrate. waterbath. | phate test (p.
Yellow, | Add Dissolve the | 83 and _ foot-
formed | (WH,).CO, "Sidue in | note p. i106),
immedi- |. ,**. "| water, and (ce) Test for
ately tlalkaline. ade Na by flame-
' A white (NH,),¢ “yf Y, test.
Ba recipitate | A white Test for NH,
indicates precipitate in the origi-
Sr | indicates nol solution
Ca by _ boiling
with sodium.
hydroxide.
Smell of am-
monia indi-
cates
NH,
indicates
|
Confirm Ba, Sr, or Ca by dissolving
the BaCrO,, SrCO,, or CaCO, in HCI,
and applying the flame-test.
— ee — ——
Note 1.—The analysis of solutions containing the foregoing
metals is commenced by the addition of ammonium chloride and
AMON, simply as a precautionary measure, the former compound
preventing partial precipitation of magnesium, the latter neutral-
izing acids, The ammonium carbonate is the barium group pre-
cipitant.
DISTILLATION. 129
Note 2.—In the preceding, and in subsequent tables of analyti-
cal processes, the leading precipitants will be found to be am-
monium salts, These, being volatile, can be got rid of toward
the end of the operations, and thus the detection of potassium and
sodium is in no way prevyented—an advantage which would be
lost if such salts as potassium carbonate or sodium phosphate were
the — precipitants employed,
on Classification.—The compounds or barium, strontium,
calcium and magnesium, have many analogies; their carbonates,
mere and arsepates are insoluble in water, which sufficiently
listinguishes them from the members of the group of alkali-metals.
The solubility of their hydroxides in water marks their connection
with the alkali-metals; the slighiness of that solubility, diminish-
ing as we advance farther and farther from the alkali-metals
(baryta being most and magnesia least soluble in water) points to
their connection with the next class of metals, the hydroxides of
which are insoluble in water. These considerations must not,
however, be over-valued. Though the solubility of their hydroxides
places barium nearest and magnesium farthest from the alkali-
metals, the solubility of their sulphates gives them the opposite
order, magnesium sulphate being most soluble, calcium sulphate
next, strontium sulphate third, while barium sulphate is practi-
eally insoluble in water, The elements are sometimes described as
the metals of the alkaline earth.
QUESTIONS AND EXERCISES,
Nar e natural sources of the various magnesium salts.—Give a
the preparation of Epsom salt.—Draw diagrams illustrative
of magnesium sulphate from magnesite and from dolomite.
soluble in water?—How is ‘Fluid Magnesia” prepared?—
Mention the effects of heat and cold on “Fluid Magnesia” .—Ascertain
how much magnesia (MgO) can be obtained from 100 grains of Epsom
; os te the amount of official Magnesium Ceuraats Mee will
yield 1 ns of magnesia.—Can magnesium be detected in presence
of bariu rn thy or calcium?—Describe the analysis of an aqueous
liquid penigater salts of barium, strontium, calcium and magnesinum.—
aed peenen are be precipitated from solutions containing ammonium
DIsTILLATION.
The water with which, in analysis, solution of « salt or dilution
ofa is effected should be pure. Well- and river-waters are
af
for th S purpose, bécause they contain dissolved salts to the
_ extent of some 20 to 60 grains or more per gallon, derived from the
»
130 THE METALLIC RADICALS,
soil through which the water percolates ; and rain-water is not in-
frequently contaminated with the dust and débris which fall on the
roofs whence it is usually collected. Such water is purified by
distillation, an operation in which the water is, by boiling, con-
verted into steam and the steam condensed again Ww water in a
separate vessel, the fixed salts remaining in the vessel in which
the water is boiled, On the large scale, the boiling is carried on
in metal boilers fitted with a hood or head in which there is a
wide lateral channel through which the steam passes; on the small
scale, either a common glass flask is employed, into the neck of
which a glass tube, bent to an acute angle, is fitted by means of a
cork; or a retort is used (a, Fig. 29), a species of long-necked
Fig. 29.
Distillation, on smal) scale.
flask, bent neur the body, by the glass-worker, to an appropriate
angle (hence the name retort, from retorgueo, | bend back), Con-
densation is effected by su rrounding the outlet tube through which
the steam passes, with cold water. In lurge stills the steam-tube,
or condensing-worm, is usually «a metal (tin) pipe, coiled into a
spirul form for the sake of compactness, and so fixed in a tube
that a few inches of one end of the pipe may pass through and
closely fit a hole bored near the bottom of the tub, Cold water
is kept in contact with the exterior of the pipe, provision being
made for a continuous supply to the bottom, while the lighter
water, heated by the condensing steam, runs off from the top of
the tub. The condenser fitted toa flask or retort may be a simple
glass tube of any size, placed within a much wider tube (a com-
mon long, narrow lamp-glass may answer for experimental opera-
ations), the inner tube being fitted to the wider one by means of
bored corks ; a stream of water passes in at one end of the enclosed
space (the end furthest from the retort), through «a small glass tube
inserted in the cork, and out at the other end through a similar
tube. The common (Liebig’ s) form of laboratory condenser is a
glass tube from one-half to three-fourths of an inch wide and a
ZINC.
yard long (4, Fig. 29), surrounded by an outer tube (¢, Fig. 29)
somewhat shorter and about two inches in diameter, having at
each extremity a neck, through which the inner glass tube passes.
The junctions of the outer tube with the inner tube are made by
means of short, wide India-rubber tubes (d and ¢, Fig. 29). An
inlet (/, Fig. 29) near the lower part of the outer tube provides
for the admission of a current of cold water, conveyed by India-
rubber tubing, while an outlet near the top (g, Fig. 29) allows the
escape of heated water into the sink. The inner tube may thus
be kept. constantly surrounded by cold water, and heated vapors
passing through it may be perfectly cooled and condensed, and
eollected in a receiver (A, Fig. 29).
In distilling several gallons of water for analytical or medicinal
purposes (Aqua Distillata, U. 5. P.), the first two or three pints
should be rejected, because they are likely to contain traces of
ammonia and other volatile impurities,
Pure water is not found in nature ; natural water always con-
tains some solid matter in solution, and also dissolved gases. The
amount and kind of matter held in solution vary with the source
of the water. Water used for distillation should not contain any
large amount of impurities, but should be such as is usually sup-
plied to large towns.
Rectification is the process of redistilling a distilled liquid.
Rectified spirit is a spirit of wine which has been thus treated,
Dry or destructive distillation is distillation in which the con-
densed products are directly formed by the decomposing influence
of the heat applied to the dry or non-volatile substances in the re-
tort or still, as in the distillation of coal in the manufacture of
coal gas,
Exercise.—Write from memory a short description of distillation.
At thia atage the student ia again recommended to read the para-
graphs on the general principles of chemical philosophy ( pages 49 to
69), and to return to them from time to time, until they are thoroughly
comprehended.
ZINC: Zn. Atomic weight, 64.9.
Occurrence, ete.—Zine is tolerably abundant in nature as sul-
phide, Zn&, blende, and carbonate, ZnCO,, calamine (from eala-
mus, a reed, in allusion to the appearance of the mineral). The
Ores are roasted to expel sulphur, carbonic anhydride, and some
. and the resulting oxide is heated with charcoal, when
the metal vaporizes and condenses on cooling, Zinc is u brittle
“ta t at a temperature somewhat below 300°F, (148,8°C, ),
it is malleable, and may be rolled into thin sheets, Above 400°
132 THE METALLIC RADICALS,
(204.4°C.), it is again brittle, and may then be pulverized, It
melts at 778°F, (411.7°C.), and is volatile at a bright red heat.
Zine in exceptionally fine powder ignites spontaneously, especially
if damp, or if stored in a warm place.
Uses.—The uses of zinc as a metal are important; alloyed with
copper and nickel it yields German silver; with twice its weight
of copper it forms brass, and as a coating on iron (the so-called
galvanized iron) greatly retards the formation of rust. Most of
the salts of zine are prepared, directly or indirectly, from metallic
zine (Zimeum, U.S. P.).
Molecular Formula,—Some remarks on this point will be made
under Mercury.
Zine Sulphate.
Experiment 1.—Heat zine (4 parts) with water (20 parts)
and sulphuric acid (3 fluid parts) in a test-tube (or larger
vessel) until no more hydrogen is evolved ; solution of zine
sulphate results, Filter (to separate the bp aeee of lead,
carbon, ete,, present in ordinary zinc), and‘ coneentrate the
solution in an evaporating-dish; on cooling, colorless prismatic
crystals of Zinc Sulphate, ZnSO,7H,O (Zinei Sulphas,
U. 8. P.) are deposited.
PA SE ae. Rt ae
Zine Sulphuric acid Zinc sulphate Hydrogen
The sulphuric acid used in this experiment must be diluted
with a considerable quantity of water, as above. Cold con-
centrated sulphuric acid does not attack zinc.
Note.—Of several methods of preparing hydrogen, the one just
described is the mest convenient; of the two or three means of
preparing zinc sulphate, it is that most commonly employed; and
of the many reactions which may be utilized for obtaining a cur-
rent of electricity, it is one of the most convenient, The apparatus
in which the reaction is affected differs according to the require-
ments of the operator: if the zinc sulphate alone is wanted, an
open dish is all that is necessary, the action being accelerated if
necessary by heat; if hydrogen is required, a closed vessel and de-
livery-tube may be used; if a current of clectricity is desired, the
zine and sulphuric acid, along with other materials, are placed in
glass or earthenware cells, the whole being arranged #0 as to form
a battery.
Purification. —Impure zine sulphate may be purified in the
same manner as impure chloride (see next experiment),
/
ZINC. 133
Zinc sulphate is isomorphous! with magnesium sulphate, and,
like that salt, loses 6H,O when heated to 300°F. (about 150°C.).
An*old name for it is white vitriol.
Zinc Chloride.
Experiment 2.—Digest zinc in hydrochloric acid mixed
with half its bulk of water; the resulting solution contains
zinc chloride. Evaporate the liquid until no more steam
escapes; Zinc Chloride, ZnCl,, in a state of fusion remains,
and, on cooling, is obtained as an upaque white solid (Zinci
Chloridum, U. 8. P.). It is soluble in water and in alcohol.
Zn + 2HC! = ZnCl, +- H,
Zinc Hydrochloric acid Zinc chloride Hydrogen
This reaction is analogous to that described in the preceding
experiment. Burnett’s deodorizing or disinfecting liquid is a solu-
tion of zinc chloride.
Purtfication of Zine Chloride or Sulphate.—Zinc sometimes con-
tains traces of iron or lead; and these, like zinc, are dissolved by
most acids, with formation of soluble salts: they may be recognized
in the solutions by applying the test described on p. 137. Should
either be present, a little chlorine water is added to the solution
till the odor of chlorine is permanent, and then the whole is well
shaken with some zinc hydroxide or the official zinc carbonate.
In this way the iron is precipitated as ferric hydroxide, and the
lead as peroxide:—
2FeCl? + Cl = — 2FeCl;
Ferrous chloride Chlorine Ferric chloride
2FeCl, + 8Zn(OH), = 2Fe(OH) + 82ZnCl,
Ferric Zine Ferric Zine
chloride hydroxide hydroxide chloride
PLC], + Cl, + 2Z%n(0H), = PbO, + 2ZnCl, + 2H,O
Tead Chlorine Zine Lead Zine Water
chloride hydroxide peroxide chloride
If zinc sulphate is being purified by the above method the
action of chlorine on any ferrous sulphate present will result in
the formation of ferric sulphate:—
6FeSO, + 3Cl, = 2Fe,(SO,), + 2FeCl,;
1 Jeomorphous bodies (igos, isos, equal, and uopdy. morphé, form) are those
which are similar in the shape of their crystals. This identity in crys-
talline form is frequently met with among substances of analogous
composition, such as zinc sulphate, ZnSQ,,7H20, and magnesium sulphate,
MgS0.,7H2.
2 It will he noticed that the atom of iron is represented, in this equa-
tion, as beth bivalent and trivalent; this will be alluded to when iron
comes under consideration.
134 THE METALLIC RADICALS.
zine carbonate will then give zine chloride as well as sulphate,
and thus the whole quantity of zinc sulphate will be slightly con-
taminated by chloride. On evaporating and crystallizing, haw-
ever, the zine chloride will be retained in the mother-liquor.
These processes of purification admit of general application,
In the Pharmacopeeia, the possible presence of impurities in the
zine is recognized, and the process of purification just deseribed
is incorporated with the process of preparation of Liquor Zinci
Chioridi, U. 8 P., nitric acid being used instead of chlorine
water to convert ferrous salt into ferric.
Zine Bromide, ZnPr,, and Zine Jodide, Zn1,, are also official,
Zinc Carbonate.
Experiment 3.—To the solution of any given quantity of
zine sulphate in twice its weight of water, add about an equal
quantity of sodium carbonate, also dissolved in twice its
weight of water, and boil; the resulting white precipitate 1s
Hydrated Zine Carbonate (Zinei Carbonas Precipiatua,
U.S. P.). As a hydroxy-carbonate, it is capable of being
represented as made up of zine carbonate, ZnCo, and zine
hydroxide, Zn(OH),, approximately in the proportion of one
molecule of the former and two of the latter, together with a
molecule of water (ZNCO,, 2Zn(OH),, H,O); these propor-
tions, however, vary considerably. It may be washed,
drained, and dried in the usual manner. It is used in the
arts under the name of zine-w/ite.
84n80, + S8H,O + 38Na,CO,
Zine sulphate Water Sodium carbonate
=/nCO,,2Zn(OH),,H,0 + 2200, + 3Na,80,
Zine hydroxycarbonate Carbonic Sodium
anhydride sulphate
Calamina Preparata is a smooth, pale, pinkish-brown powder,
obtained by calcining and powdering native zine carbonate or eal-
amine, and freeing the product from gritty particles by elutriation,
Prepared calamine is chiefly zinc carbonate with some oxide of
Iron, ete.
Elutriation (Lat. elutriatus, from elutrio, I decant; eluo, T wash
out). This fractional operation consists of decanting off water or
other liquid containing lighter and finer particles in suspension,
from heavier und courser particles which have become deposited,
The decanted fluid yields a sediment of the fine particles on
standing. By allowing varying intervals of time to elapse
between the shaking and the decantation, and by using fluids of
different specific gravities and different degrees of limpidity or
ZINC. 155
viseidity, substances of different specific gravities, or particles of
different degrees of fineness of any one substance, may be sepa-
rated from each other.
Zinc Acetate.
Experiment 4.—Collect on a filter the precipitate obtained
in the last experiment, wash with distilled water, and dissolve
a portion in concentrated acetic acid; the resulting solution
eontains zinc acetate, and, on evaporating and setting aside,
yields Jamellar pearly crystals of zine acetate, Zn(C,H,O,),
2H.O (Zinei Acetas, U.S. P.).
ZnO, 2Zn( 01 |p, HyO —-GHCsHsOe = SZn(CyHsOy)s + GHYO + COg
Zine hydroxycarbonate Acetic acid Zinc acetate Water Carbonic
anhydride
Zinc Oxide.
Experiment 5.—Dry on a water-bath the remainder of the
precipitated zinc carbonate obtained in experiment 3, and then
heat it in a small crucible until a sample taken out of the
erucible does not effervesce on the addition of a dilute acid; the
product is Zinc Oxide (Zinei Oxidum, U.S. P.), much used
in the form of Ointment ( Unquentum Zinci Oxidi, U.S. P.).
ZnCO,,2/n(0H),,1,0 = 3%n0 + 8H,O + CO,
Ziue hydroxycarbonate Zine oxide Water Carbonle
anhydride
Note.—Zine oxide prepared as above is yellow while hot, and
of a very pale yellow or slight buff tint when cold, not actually
white like the oxide prepared by the combustion of zine in air.
The preparation of the latter variety, which also occurs in com-
Fic. 30. b.
The blowpipe.
merce, can only be practically accomplished on the large scale;
but the chief features of the action may be observed hy heating a
piece of zine on charcoal in the blowpipe-flame (a, Fig. 80) till it
THE METALLIC RADICALS.
burns; flocks escape, float about in the air, and slowly fall. These
were formerly called Flores Zinci, Lana Philosophica, or Nihilum
Album. Zine oxide slowly absorbs carbonic anhydride and water
from moist air, and becomes converted into hydroxycarbonate,
A clear blowpipe-flame consists of two more or less sharply
defined portions (6,F ig. 80), an inner cone, at the apex of which
there are hot hydrocarbon gases ready to combine with oxygen,
and an outer cone, at the apex of which there is excess of hot
oxygen, At the latter point oxidizable metals, etc., are readily
oxidized, as in the foregoing experiment, and that part of the
flame is therefore termed the oxodizing flame; in the inner flame,
oxides and other compounds are reduced to the metallic state,
hence that part is termed the reducing flame (a grain of lead
acetate may be employed for illustration), A blowpipe-flame is
much altered in character by slight variations in the position of
the nozzle of the blowpipe, by the form of the nozzle, by the
force with which air is expelled from the blowpipe, and by the
character of the jet of gas.
Zinc Valerandate.
Experiment 6.—Zinc Valerandate, or rather, zinc iso-valer-
andate, Zn(C,H,O,), 2H,O (Zinei Valerandas, U. 8. P. ), is
prepared by saturating iso-valerandic acid with zine carbon-
ate or by mixing concentrated solutions of zinc sulphate and
sodium iso-valerandate, cooling, separating the white pearly
crystalline precipitate, evaporating the solution at 200° F.
(93,3° C.), to a small volume, cooling, again separating the
lamellar crytals, washing the whole product with a small
quantity of cold distilled water, draining, and drying by ex-
posure to air at ordinary temperatures. Zinc iso-valerandate
is soluble in ether, alcohol, and hot water. See also valer-
andie acid.
ZuS5O0, + 2NaC,H,O, — NaSO, + Zn(C,H,0,)
Zine sulphate Sodium iso- ‘valerandate Sodium sulphate Zine iso- Vvaleram ate
Zine Sulphide and Zine Hydroride are mentioned in sub-
sO. paragraphs. The formula of Zinc Sulphite is ZnSO,,
5H,O
Zine Pheno!sulphonate, Zn(C,H.08),,8H,0( Zinei Phenol-
sulphonas), and Zinc Stearate, (Zinei Stearas), are included
in the Pharmacopeia.
Analylical Reactions of Zine Salts.
1, To asolution of a xine salt (sulphate, for example), in
a test-tube, add solution of ammonium hydrosulphide,
ZINC, 137
NH SH; a white precipitate of zinc sulphide, Zns, is pro-
duced which is insoluble in acetic, but soluble in dilute
hydrochloric or sulphuric acid.
Note.—This is the only white sulphide that will be met with.
If the zinc salt contains iron or lead as impurities, the precipitate
will have a dark appearance, due to admixture with the sulphides
of these metals, which are black. Aluminium hydroxide, which
is white and may also be precipitated on the addition of ammon-
ium hydrosulphide, is the only substance for which zinc sulphide,
is likely to be mistaken, or which is likely to be mistaken for
zine sulphide. As will be seen immediately, there are good
means of distinguishing these substances from each other.
2. To a solution of a zinc salt add ammonia water; a
white precipitate of zine hydroxide, Zn(OH),, is formed.
Add excess of the reagent; the precipitate is redissolved.
This reaction at once distinguishes a zinc salt from an alumi-
nium galt, unless the solution of the latter is very dilute,
aluminium hydroxide being almost insoluble in dilute am-
TOD LA,
Other Analytical Reactions.—Potassium or sodium hy-
droxide affords a reaction similar to that just mentioned, the
zine hydroxide redissolving if the alkali does not contain too
much carbonate, The solution contains potassium or sodium
zincate :—
(OH), + 2KOH = K.%Z0, + 2H,0
Zine Caustic Potassium Water
hydroxide potash zincate
(Metallic zine dissolves in solution of potassium or sodium
hydroxide giving hydrogen and potassium or sodium zincate :
—fn+2KOH—K,7n0,+-H,.) Ammonium carbonate yields
a white precipitate of basic zinc carbonate, soluble in excess,
Potassium and sodium carbonates gives a similar precipitate,
which is not redissolved if the mixed solution and precipitate
be well boiled to expel carbonic anhydride. Potassium
ferrocyanide produces a white precipitate of zinc ferrocyanide,
Zn,Fe(Cn),.
x esiium sulphate, which is isomorphous with and indis-
3 in appearance from zinc sulphate, does not yield
preci When either potassium ferrocyanide or ammonium
ivdvpeul hide is added to its aqueous solution.
Antidotea.
—There are no efficient chemical means of counteract-
ing the poisonous effects of zinc. Large doses, fortunately, act as
1338 THE METALLIC RADICALS.
powerful emetics, If vomiting has not occurred, or apparently to
an insufficient extent, solution of sodium carbonate (common
washing soda), immediately followed by white of egg and denml-
cents, may be administered, and the stomach then be cleared.
QUESTIONS AND EXERCISES.
Give the sources and uses of metallic zinc.—Give a diagram repre-
senting the action of zine on dilute sulphuric acid.—How may solutions
of Zine Chloride or Sulphate be purified from iron salts? Give equations
for the reactions.—Give the formula of the official Zinc Carbonate, and
illustrate by a diagram the reaction which takes place in its production.
—Give an equation representing the preparation of Zinc Acetate.—In
what respect does Zinc Oxide, resulting from the ignition of the carbon-
ate, differ from that produced during the combustion of the metal ?—
How is Zine Iso-valerandate prepared and what are its properties —
Name the more important tests for zinc.—How would you distinguish,
chemically, between solutions of Zine Sulphate and of Alum’?—Give
reactions distinguishing Zine Sulphate from Magneium Sulphate.—
Describe the treatment in cases of poisoning by zinc salts,
MANGANESE: Mn. Atomic weight, 54.6.
Source, — Manganese is a constituent of many minerals, and is
met with in abundance in the south-west of England, in Aber-
deenshire, and in most countries of Europe, as black oxide, MnO,,
pyrolusite (from rip, pur, fire, and Aiov, /usis, a loosing or resolving,
inallusion to the readiness with which it is split up by heat into
a lower oxide and oxygen). This mineral occurs as a steel-grey
mass of prismatic crystals, or in black amorphous lumps,
Uses.—Metallic manganese, which may be isolated, among
other methods, by the action of sodium on manganese fluoride, is
used in alloy with iron in the manufacture of some varieties of
steel. The black oxide is an important agent in the production
of chlorine, and in the preparation of manganates and permangan-
ates, purple glass, and black glaze for earthenware. Mangani
Dioxidum Proveipitatum, Manganit Hypophosphis aud Mangani
Sulphas are included in the Pharmacopaia.
EXPERIMENTS HAVING BOTH SYNTHETICAL AND
ANALYTICAL INTEREST.
Experiment 1—Boil some black manganese oxide with
concentrated hydrochloric acid in a test-tube or flask, placed
in a fume-cupboard, until chlorine is no longer evolved; filter;
the filtrate is a solution of manganous choride, MnCl,,MnQ,-+-
4HCl= MnCl, +2H,O-+Cl,.
MANGANESE, 139
This is the reaction commonly employed in the preparation of
chlorine. It is also a ready method of preparing a manganous salt
for analytical experiments, Coupled with the application of
reagents to the filtrate, the reaction is one of those by which a
black powder or mineral would be recognized as black manganese
oxide. Black manganese oxide also dissolves in co/d concentrated
hydrochloric acid, forming a dark-brown solution which contains
a chloride, MnCl,, mixed, probably, with other manganese chlo-
rides.
Experiment 2.—Heat a manganese compound with a grain
or two of potassium hydroxide or carbonate and a fragment of
potassium nitrate or chlorate on platinum foil in the blowpipe-
flame; a green mass containing potassium manganate, K,MnQ,,
is formed. Boil the foil and the fused mass in water; the
manganate dissolves yielding a green solution which soon
changes to pu le owing to the formation of potassium per-
manganate, nO,. Carefully performed, this is a delicate
test for manganese.
This reaction is the one by which potassium permanganate
(Potamium Permanganas,U. 5. P.), is prepared. Equations show-
ing the action which occurs in making the salt have already been
given in connection with the compounds of potassium (see p. 81).
Instead of converting the manganate by ebullition (as described
on p. 81), and neutralizing the free alkali by acid, whereby one-
third of the manganese is precipitated, chlorine may be passed
through the cold solution until the green color is entirely changed
to le. 2K,Mn0,+ Cl,=2KMn0,+ 2KCl.
ions of potassium and sodium manganates and permanganates
are in common use as green and purple disinfecting fluids, They
act by oxidizing organic matter, the manganic or permanganic
radical being reduced and a dark-brown manganite formed, For
this reason asbestos should be used instead of paper in filtering
the solutions.
The changes in color which the green manganate undergoes
when dropped into warm water gave rise to the old name mineral
, by which the manganate is still sometimes described.
Experiment 3.—Make a borax bead by heating a fragment
of borax on the end of a platinum wire in the blowpipe-
flame until a clear transparent globule is obtained. Place a
minute particle of a manganese compound, or a drop of a
solution of a manganese salt, upon the bead and heat it again
in the oxidizing flame. A bead of pale violet or amethyst
tint is uced. (This is useful as an analytical reaction,
and iti ates the use of black manganese oxide in pro-
140 THE METALLIC RADICALS,
ducing common purple-tinted glass), Expose the bead to
the reducing part of the flame (p. 136), the color disappears.
The change is owing to the reduction of the manganic com-
pound to a manganous compound which is nearly colorless
(compare ferrous and ferric compounds, p. 151). This action
also illustrates the use of black manganese oxide in glass-
manufacture. Glass, when first made, is usually of a green
tint, owing to the presence of small quantities of ferrous com-
pounds; the addition of the manganese oxide to the materials
converts the ferrous into ferric compounds, which have com-
paratively little color, it itself being thereby reduced to mangan-
ous oxide which also gives but little color. If excess of the
manganese oxide is added, a purple tint is produced.
Manganese borate is an article of commerce used for the pre-
paration of drying oil and oil varnishes, When moist, it acts as
an oxidizing agent with great facility, especially on warming.
Experiment 4.—Through a solution of a manganous salt,
acidulated with hydrochloric acid, pass hydrogen sulphide ;
no precipitate is produced. Add ammonia; the ammonium
Hvdicontl phide thus formed produces a yellowish-pink or flesh-
tint precipitate of manganous sulphide, MnS.
This reaction is characteristic, manganese sulphide being the
only flesh-colored sulphide known. The salt used may be the
manganous chloride prepared in experiment 1; but such erude
solutions usually give a black precipitate with ammonium hydro-
sulphide, owing to the presence ofiron. ure manganous chloride
may be obtained by boiling the impure solution with manganous
carbonate; the latter decomposes the ferric chloride, with the
production of ferric hydroxide and more manganous chloride, and
the evolution of carbonic anhydride.
To the recently precipitated manganous sulphide add acetic
acid; it dissolves. This solubility permits of the separation of
manganese from nickel, cobalt and zinc, the sulphides of which
are insoluble in dilute acetic acid, To express the fact in another
way, manganese is not precipitated by hydrogen sulphide from a
solution containing free acetic acid.
Experiment 5.—To a solution of a manganous salt add
ammonia water ; a white precipitate of manganous hydroxide,
Mn(OH), is produced. Add excess of ammonia water ; some
of the precipitate is dissolved, and may be detected in the
quickly filtered solution by the addition of ammonium hydro-
COBALT. 141
sulphide. But both precipitate and abethic rapidly absorb
oxygen, the manganese passing into a more highly oxidized
condition, in which it is insoluble in ammonia. Potassium
and sodium hydroxides give a similar precipitate insoluble in
excess. The precipitate rapidly absorbs oxygen, becoming
brown, and aren pr passing into a higher state of oxidation.
to a solution of a manganous salt add
dilute nitric ate altri acid, and either red lead or lead peroxide, and then
boil; a red tint is imparted to the liquid, due to the formation
of permanganic acid. If chlorides are present, the mangan-
ese, etc., should be separated by means of sodium hydroxide
solution, the precipitate well washed, dissolved in nitric
acid, and the oxide then added. (Crum). Or the chlorides
may be got rid of by heating with sulphuric acid until all
hydrochloric acid has been expelled (Alcock), and then ap-
plying Crum’s test. An improvement on Crum’s test consists
in warming the solution to be tested, which should be free
from chloride, with a small quantity of ammonium persul-
hate to which a of a dilute solution of silyer nitrate
been added. (H. Marshall). The purple color of the
solution of permanganic acid is much more easily observed
when this method is employed.
COBALT: Co. Atomic Weight, 58.56.
Sources, —Cobalt occurs sparingly in nature as the arsenide,
CoAs,, fin-while cobalt, and oceasionally as a double arsenide
and sulphide, CoAsS, or cobalt-glance (from glanz, brightness, in
allusion to its lustre).
Uses, —Its chief use is in the manufacture of blue glass. A
cobalt compound is also the coloring constitutent of smait, (from
smell, « corruption of me/f), a variety of blue glass reduced to a
fine powder and used as pigment by paper-stainers and others,
and Botte ee tion by laundresses to conceal the yellow tint of imper-
Cobalt salts, which are mostly reddish and yield pink or red
sola may be obtained from the oxide, CoO; and the oxide
from a mixture of sand and roasted ore which is chie fly
cobalt arsenate. Metallic cobalt is obtained by reducing cobalt
oxide (by heating in a current of hydrogen), or by heating cobalt
oxalate in the absence of air,
THE METALLIC RADICALS.
Analytical Reactions of Cobalt Salts.
1. Pass hydrogen sulphide through an acidulated solution
of a cobalt salt (cobalt chloride, CoCl,, or nitrate, Co( NO,),,
for example); no precipitate is produced. Add ammonia
water; the ammonium hydrosulphide thus formed causes pre-
cipitation of black cobalt sulphide, CoS. (The moist precipi-
tate slowly absorbs oxygen from the air, yielding some cobalt
sulphate, CoSO,).
2. Gradually add ammonia water to a solution of a cobalt
sult; a blue precipitate of basic salt is produced. Add excess
of ammonia; the precipitate is dissolved, yielding a nearly
colorless solution, which is rapidly oxidized by the oxygen of
the air and becomes brown thereby. Potassium and sodium
hydroxides also produce a precipitate of basic salt insoluble
In excess.
3. Make a borax bead by heating a fragment of borax on
the end of a platinum wire in the blowpipe-flame until a clear
transparent globule is obtained. Place a minute particle of
any cobalt compound, or a drop of a solution of a cobalt salt,
upon the bead and heat it again; a blue bead results, in both
oxidizing and reducing flames. This is a delicate test for
cobalt.
4. Toa solution of a salt of cobalt add solution of potassium
cyanide until the precipitate which at first forms has entirely
redissolved, and further add considerable excess of the cyanide,
Then add solution of potassium hydroxide in considerable
quantity and an oxidizing agent such as bromine water, and
warm, Potassium cobalticyanide, K,CoC,N,, is formed in solu-
tion but no precipitate is produced. When a nickel solution
is similarly treated, the nickel is completely precipitated as
black nickelic hydroxide; hence this action affords a means
of separating these closely allied metals from each other.
5. To asolution ofa cobalt salt add excess of a freshly pre-
pared solution of potassium nitrite in dilute acetic acid. The
cobalt is completely precipitated as yelloay potassium cobaltic
nitrite (Fischer’s Salt), K,Co(NO,),. Nickel salts do not
give any corresponding reaction.
Invisible Ink.— Many cobalt compounds containing water
of crystallization are light red, and in the anhydrous state
are more or less blue. Prove this by writing some words on
paper with a solution of cobalt chloride sufficiently dilute for
the characters to be invisible when dry: hold the sheet before
NICKEL. 145
a fire or over a flame; the letters at once become distinctly
visible, and of a blue color. Breathe on the words, or set
the sheet aside for some time, the characters become once
more invisible, owing tothe absorption of moisture. Hence
solution of cobalt chloride forms one of the so-called syinpa-
thetic inks.
NICKEL: Ni. Atomic weight, 58.3,
Sources.—The ores of nickel and cobalt are commonly associated
in nature. Indeed it is from speiss, a nickel arsenio-sulphide ob-
tained in the manufacture of smalt, a pigment of cobalt which
has already been mentioned, that much of the nickel of com-
merce has hitherto been obtained. Garnierite, magnesium and
eR silicate, containing no cabalt, is also a valuable source of
nickel.
Usea,—Nickel is used in the preparation of the white alloy
known as German or nickel silver, and is extensively employed
wid seen iron,
kel acits, which are generally green and yield a green solu-
tions, are chiefly mide, directly or indirectly, from the metal itself.
The lutter is obtained by reduction of the oxide by strongly heating
it with charcoal.
Analytical Reaction of Nickel Salts.
1. Pass hydrogen sulphide through an acidulated ——
of a nickel salt (nickel chloride, NiCl,, nitrate, Ni( NO,),,
sulphate NiSO,); no precipitate is produced, Add ammo-
nia water; the ammonium hydrosulphide thus formed causes
precipitation of black nickel sulphide, Ni8.
Note.—When nickel sulphide is precipitated by the addition of
ordinary ammonium hydrosulphide, which contains free sulphur,
difficulty is experienced i in obtaining a clear liquid on filtering
the mixture, owing to the fact that nickel sulphide dissolves to
some extent in excess of yellow ammonium hydrosulphide, form-
ing a dark-colored liquid from which nickel sulphide separates
slowly on exposure to the air. From this filtrate, the whole of
the nickel can be separated in the form of sulphide by adding
exceas of acetic acid (which decomposes the yellow ammonium
he solvent of the nickel sulphide) and filte ring
It can also be separated by driving away the ammonium
serltewulphide by evaporation, and refiltering. In the latter
method, some of the nickel sulphide usually undergoes oxidation
into nickel sulphate, NiSO,, which passes into solution and must
144 THE METALLIC RADICALS.
be removed by reprecipitation as sulphide (by adding a few drops
of solution of ammonium hydrosulphide and then acidulating
with acetic acid), and filtration, It is occasionally practicable
to avoid the difficulty by precipitating the nickel sulphide from
an ammoniacal solution by means of hydrogen sulphide, or by
using freshly-made ammonium hydrosulphide in which nickel
sulphide is insoluble.
2. Add ammonia water drop by drop to a solution of a
nickel salt ; a pale-green precipitate of basic salt is produced,
especially on boiling the mixture, Add excess of ammonia;
the precipitate dissolves, yielding a blue solution. Potassium
and sodium hydroxides produce a pale-green precipitate of
of nickel hydroxide, Ni(OH),, inaoluble in excess.
3. Nickel salts color a borax bead reddish-yellow when
heated in the oxidizing flame; on heating in the reducing
flame, the bead becomes gray and opaque,
4. To a solution of a nickel salt add solution of potassium
cyanide; nickel cyanide, Ni(CN ),, is precipitated. Add excess
of solution of potassium cyanide; the precipitate is dissolved
with formation of potassium nickel cyanide, K,Ni(CN),. Then
add solution of potassium hydroxide in considerable quantity
and bromine water, and warm. The nickel is completely pre-
cipitated as black nickelic hydroxide, Ni(OH),,
QUESTIONS AND EXERCISES,
Name the commonest ore of mungunese ; and give an equation descrip-
tive of its reaction with hydrochloric acid.—Explain the formation of
potassium permanganate, giving equations.—How do potassium mwn-
ganate and permanganate act as disinfectants }—What are the chief tests
for manganese ?—What are the chief uses of the compounds of cobalt ?—
How is cobalt analytically distinguished from nickel ?—Mention appli-
cations of nickel in the arts.—What is the usual color of nickel salts?
DIKECTIONS FOR APPLYING THE ANALYTICAL REACTIONS DE-
SCRIBED IN THE FOREGOING PARAGRAPHS TO THE ANALYSIS
OF AN AQUEOUS SOLUTION OF SALTS CONTAINING ONE OF THE
——
METALS, ZINC, MANGANESE, COBALT, NICKEL,
First note the color of the solution :-—
Solutions of zinc salts are colorless.
NICKEL. 145
Solutions of manganous salts are colorless or very pale pink,
Solutions of cobalt salts are rose red.
Solutions of nickel salts are green.
Add ammonium chloride, ammonia water until the liquid, after
oO Ri smells of this reagent, and then ammonium hydrosul-
A white precipitate indicates zinc,
A buff precipitate indicates manganous salt,
_A black precipitate indicates a cobaltous or a nickel salt. To
distinguish between cobalt and nickel, add ammonia water
gradually to a portion of the original solution, without previously
adding ammonium chloride. Cobalt gives a blue precipitate,
soluble in excess and yielding a brownish solution which gradually
darkens. Nickel gives a green precipitate which dissolves in
excess yielding a blue solution, .
TABLE OF SHORT DIRECTIONS FOR APPLYING THE ANALYTICAL
REACTIONS DESCRIBED IN THE FOREGOING PARAGRAPHS TO
THE ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF TWO OR
ee SS SS
MORE OF THE METALS, ZINC, MANGANESE, COBALT, NICKEL,
If the solution is neutral, acidulate it with acetic acid ; if it
is acid, add ammonia water until alkaline and then acidulate
with acetic acid. Through the acetic acid solution pass hydrogen
ee until the liquid, after shaking, smells of this gas;
Previpitate. Filtrate.
Zn, Co, Ni. Mn.
Boil with MIC! and a little HNO, add KOH in ex- | Add NH,OH
cess; filter. in excess.
- Buff ppt.
Preeipitate, Filtrate.
— Co, Ni. | Zn.
Dissolve in HC1; test for Nias described | Add
in Reaction 4 (r 144), If Ni absent, test | NASH
solution for Co hy borax bead (p. 142) ; if PI
Ni present, filter off nickelic hydroxide, | White ppt.
and test filtrate for Co by borox bead.
4 Ammonium bydrosulphide added to an ammoniacal solution con-
iting ammoniim chloride, is the group reagent for zinc, manganons,
cobaltous, and nickel salts.
a9
THE METALLIC RADICALS,
ALUMINIUM : Al. Atomic weight, 26.9.
Occurrence.—Aluminium is abundant in nature, occurring
chiefly as silicate, in clays, slate, marl, basalt, and many other
minerals, Mica or laminated tale consists chiefly of aluminium,
iron, magnesium, and potassium silicates. Spinelle is mag-
nesium aluminite, Corundum, sapphire, ruby, and amethyst are
almost pure aluminium oxide. mery is an impure aluminium
oxide. otten stone is a soft, friable aluminium silicate containing
a little organic matter. Cryolite is a double sodium and alumi-
nium fluoride.
. The metal aluminium is obtained from the double sodium and
aluminium chloride by the action of metallic sodium (the source
of the chloride being the. mineral bawxite, a more or less ferru-
ginous aluminium hydroxide ); also by the electrolysis of cryolite,
It is readily attacked by various acids, but dilute sulphuric acid
only acts upon it slowly.
Aluminium is a remarkably light metal, and in consequence of
this property and of the fact that it is practically unchanged by
exposure to the air, it is now largely employed for the mountings
for opera glasses, etc., and in making cooking utensils for the use
of travellers. It readily forms alloys (see p. 209) with other me-
tals. One part of aluminium fused with nine of copper gives a/umi-
nium bronze, Aluminium steel is a hard and tenacious alloy of
iron with a little aluminium.
Alum (A/umen, U. 8. P.), aluminium and potassium sulphate,
AIK(S0,),, 12H,O, may be obtained from alum shale, an alumi-
nous schist (from oycord¢, achistos, divided) containing iron pyrites
and some bituminous matter, by exposure to air; oxidation in
presence of moisture gives rise to the formation of aluminium sul-
phate, ferrous sulphate, and silica, from the aluminium silicate
and iron bisulphide, FeS,, (iron pyrites) originally present in the
shale. The aluminium sulphate and ferrous sulphate are dissolved
out of the mass by water, and potassium sulphate or chloride is
wlded; on concentrating the liquid, alum crystallizes out, while
the more soluble ferrous sulphate remains in the mother-liquor,
Alum is more frequently prepared by directly decomposing the
iluminium silicate in the calcined shale of the coal measures by
means of hot sulphuric acid, potassium salts being added from
time to time, until a solution is obtained which is sufficiently con-
centrated to crystallize. The liquid, well agitated during cooling,
deposits alum in minute crystals termed a/um-flour, which is after-
ward recrystallized.
Alums.—A series of double sulphates, analogous in composition
to the alum just mentioned, have been prepared in which sodium
or ammonium may take the place of potassium, and iron or
chromium may take the place of aluminium, These salts are also
ALUMINIUM. 147
called alums; their general formula is M”’M/(SO,),, 12H,O; and
they all crystallize in octahedra, The student should note that
iron alum (below) and chrome alum (p, 168) do not contain
aluminium, Ferri et Ammonii Sulphas, U.S. P., is iron alum,
FeN H,(80,),, 12,0.
Ordinary alum commonly occurs in colorless, transparent, octa-
hedral erystals, massed in lumps, which are roughly broken up
for trade purposes, but which still exhibit the faces of octahedra.
The commercial article sometimes contains potassium sulphate
tash alum), sometimes ammonium sulphate (ammonia alum),
Note.—The aluminium atom is trivalent, and the formula for
aluminium chloride is AICI, The composition of aluminium
sulphate is never represented by means of a formula with a single
atom of aluminium, since this would involve writing AI(0,);
In order to avoid writing a fraction, the whole formula is doubled,
when we get Al,(SO,),.
ent, — pare alum by heating a small quantity of
pow pipeclay (aluminium silicate) with about twice its weight
of sulphuric acid for some time, dissolving the resulting alumi-
nium sulphate and excess of sulphuric acid in water, and add-
ing potassium carbonate to the clear filtered solution until, after
well stirring, the excess of acid is neutralized, (If too much car-
bonate be added, the aluminium hydroxide which is precipitated
nag the carbonate is first poured in will not be redissolved even
mixing. Perhaps the readiest indication of neu-
trality in this and similar cases is the presence of a small quantity
act precipitate after stirring and warming the mixture.) On
Bales ria the clear solution, crystals of alum are obtained,
luminium Sulphate or “Alum-cake, ” Al,(BO,),, 16H,0, pre-
pared from natural silicates in the manner just described, is a
common article of trade, serving most of the manufacturing pur-
usr), for which alum was formerly employed. (A/wmini Sulphaa,
Dried Alum (Alumen Exvsiccatum, U.S. P.), is potassium alum
from which the water of erystallization has been expelled by heat.
calculation from the formula, it will be found that alum con-
between 45 and 46 percent, of water. Dried alum rapidly
aeabapitia water from the air, and is slowly but completely soluble
in oe ‘At 1 esate above 400° F.(204.4° C.), ammonium
decomposed, water, ammonia, and sulphuric anhydride
oi and pure aluminium oxide, Al,O,, remaining.
, or Rock alum (Fr. roe che, rock), is the name of an
native variety of alum containing iron, The article sold
Laden is generally an artificial mixture of common alum
with ferric oxide.
148 THE METALLIC RADICALS.
Analytical Reactions of Aluminium Salts.
1. To a solution of an aluminium salt (alum, for example,
which contains aluminium sulphate) add ammonium hydro-
sulphide; a white gelatinous precipitate of aluminium hydrox-
ide is produced;—
Al,(SO,), + 6NH,SH + 6H,O = 2A1(OH), + 3(NH,),SO, + 61,8
2. To a solution of alum add ammonia water; aluminium
hydroxide is precipitated; add excess of ammonia water; the
precipitate is practically insolube.
Principle of Dyeing by help of Mordants.—Precipitated
aluminium hydroxide has great affinity for vegetable color-
ing-matters, and also for the fibre of cloth, Repeat experi-
ment 2, but before adding the ammonia water, introduce into
the test-tube some decoction of logwood, solution of cochineal,
or other solution of an animal or vegetable coloring-matter.
Now add the reagent and set the tube aside for the precipitate
to settle; the latter takes down with it all the coloring-matter.
In dye works, the undyed fabrics are treated with solutions of
aluminium acetate in such a manner as to deposit aluminium
hydroxide within their fibres, and are then passed through
the coloring solutions, from which the hydroxide abstracts
coloring-matter. Some other metallic hydroxides, notably
those of tin and iron, resemble aluminium hydroxide in this
respect; they are termed mordants (from mordens biting);
the substances they form with coloring-matters are called
lakes,
3. To a solution of alum add solution of potassium hydrox-
ide; aluminium hydroxide is precipitated. Add excess of the
reagent, and agitate; the precipitate dissolves.
Aluminium hydroxide may be precipitated from this solu-
tion by neutralizing the potassium hydroxide with hydro-
chlorie acid, and adding ammonia water until, after shaking,
the mixture smells of ammonia; or by adding a sufficient
quantity of solution of ammonium chloride to the alkaline
liquid, and boiling until ammonia is no longer evolved.
4. To « solution of alum add solution of potassium or
sodium carbonate. A precipitate of aluminium hydroxide
(Alumini Hydroxidum, U.S. P.) is produced, and carbonie,
anhydride escapes:—
Al,(80,),+8K,CO, + 3H,0—2A1(0H),+3K,80,+30C0,
IRON. 149
QUESTIONS AND EXERCISES.
Enumerate the chief natural compounds of alomininm?—Write down a
formula which will represent either of the alums.— Which alum is official,
and commonly employed in the arts ?—State the source and explain the
formation of alum,—What is the ral fs stulline form of alum ?—Caleulate
how mueh dried alum is theoretically producible from 100 pounds of
meen alum. Awns,, 54 lb. 7 oz.—Show that ordinary ammonium alum
es reo of yielding 11.269 shee of aluminium oxide.—Why are
aluminium compounds used in dyeing?—How are aluminium salts ana-
lytically distinguished from zine salts ?
IRON : Fe. Atomic weight, 55.5,
Sources. —Compounds of iron are abundant in nature. Mag-
netie Iron Ore, or Loadstone (Lodestone or Leadstone, from the
Saxon /edan, to lead, in allusion to its, or rather, to the use of
an made from it, in navigation), Fe,0,, i is the chief ore from
ch Swedish iron ismade. Much of the Russian iron is made
from Tron Ore (from specu/um, a mirror, in allusion to
to the lustrous nature of the crystals of this mineral); this and
Red Hematite (from alua, haima, blood, so named from the color
of its streak), an ore raised in Lancashire, are composed of ferric
oxide, FeO, Brown Hematite, an oxyhydroxide, Fe,Q(OH),,
is the source of much of the French iron. Needle iron ore, Or
githite, is also an oxyhydroxide, FeQ(OH). Spathic Iron Ore (from
a slice, allusion to the lamellar structure of the ore) is
ta eg FeCO,. An impure ferrous carbonate forms
Tronstone, whence most of the English iron is derived.
The chief Scotch ore is also an impure carbonate, containing much
bituminous matter: it is known as Black Band. Tron Pyrites
Comet, pur, fire, in allusion to the production of sparks when
harply struck,) FeS,, is a yellow, lustrous mineral, now largely
emp as a source of sulphur. As met with in coal, it is
commonly termed coal brasses. Ferrous bicarbonate, chloride and
sulphate, sometimes occur in springs, the waters of which are
hence termed chalybeate (chalyba, steel).
of Iron.—The manufacture of iron from its ores is
carried on a8 a continuous process by means of the blast-furnace, a
high structure built with fire-bricks. Most manufacturers em ploy
a of ores—the oxide ores simply in the condition in
w are mined, and some other ores after the preliminary
part roasting, or strongly heating in air, to convert them
into oxide, The mixed nae ecie with coal and limestone, are
i into the of the blast-furnace, while a current of heated air,
: 1 in at 1¢ bottom under considerable pressure, causes the
ly, and thereby maintains a very high tempera-
mace. In the course of their passage. dow n from
150 THE METALLIC RADICALS.
the top, the iron oxides give up their oxygen to form carbonic
anhydride, and the reduced iron trickles down and collects at the
bottom of the furnace, On its way down, the melted metal is
protected from the oxidizing action of the hot-air blast by the
slag, a fusible glassy substance which is produced by the interac-
tion of the limestone with the sand and clay present as impurities
in the ores. The fused slag collects in a layer which lies on the
top of the melted iron and is occasionally drawn off. The iron
is also drawn off from time to time, and is allowed to flow into
narrow branched gutters moulded in sand, where it cools and
solidifies, and is afterward broken up into fragments which con-
stitute pig-iron—the form in which cast-iron is met with in com-
merce,
The cast-iron thus produced may be converted into wrought-
iron by burning out the 4 or 5 percent. of carbon, silicon, and
other impurities present, by oxidation in a furnace—an operation
termed puddiing, Steel is iron containing from 1 to 2 percent, of
carbon. It is new made by the Bessemer process, which consists
in burning out from cast-iron the variable amount of carbon it
contains, and then adding melted iron containing a known pro-
portion of carbon. The official iron (ferrum, U. 8. P-.), is
‘metallic iron, in the form of fine, bright and non-elastic wire,”’
a form in which iron is conv eniently employed for conversion into
its compounds. In the form of a fine powder, metallic iron is
employed as a medicine (see p, 162).
Properties. —The specific gravity at 15.56 .C., of pure iron is
7.844; of the best bar, or wrought iron 7.7. Its color is bluish
white or gray. Bar iron requires the highest heat of a wind-fur-
nace for fusion, but below that temperature it assumes a pasty
consistence, and in that state two pieces may be joined or welded
(Germ. wellen, to join) by the pressure of blows from a hammer.
A little sand thrown upon the hot metal facilitates this operation
by forming with the superficial coating of oxide of iron a fusible
slag, which is dispersed by the blows: the purely metallic surfaces
are thus better enabled to come into thorough contact and enter
into perfect union, Tron is highly ductile, and of all common
metals possesses the greatest amount of tenacity. Ata high tem-
perature it burns in the air, forming | black magnetic oxide.
Ordinary tron rust is chiefly brown ferric hydroxide or oxhydrox-
ide, with u little ferrous oxide and carbonate; it is produced by
action of the moisture and carbonic anhydride of the air and sub-
sequent oxidation. Steam passed over iron heated to redness
yields hydrogen and magnetic oxide of iron.
Quentivalence af Iron, Ferrous and Ferrie Salts,—In its union
with other elements and with radicals, to form salts, iron exhibits
the property of combining with these in two proportions 80 as to
rive rise to two distinct sets of salts. In one of these sets, Iron
appears as a bivalent metal, the formula of the chloride being
FERROUS SALTS. 151
FeCl, that of the sulphate, FeSO,, ete. In the other set, iron is
trivalent, the formule of the chloride and sulphate being FeC]
and Fe,(S0,), respectively. These two sets of salts are regarde
as related to the two basic oxides of iron, FeO and Fe,O, (the
place of the oxygen of the basic oxides being taken by acid
radical), and they are known as ferrous and ferric salts respec-
tively. ‘Thus the ‘lower’? chloride, FeCl, (or chloride contain-
ing the smaller proportion of chlorine) is ferrous chloride, while
the ‘‘ higher ”’ chloride, FeCl, (orechloride containing the larger
proportion of chlorine), is ferric chloride. When the analytical
reactions of iron salts come to be studied, it will be found that
those of the ferrous and ferric salts are quite different from each
other and enable the student to ascertain in which of the two
forms of combination the iron is present, This feature of forming
two separate sets of salts is not peculiar to iron, but is met with
in the cases of copper, mercury, and various other metals, The
terminations ous and ic are employed in these cases in a consistent
manner, the former always denoting the compound containing the
smaller, and the latter that containing the larger proportion of
oxygen (in the case of the basic oxides) and of acid radical (in
the case of the salts),
FERROUS SALTS,
Ferrous Sulphate. Iron Protosulphate.
Experiment 1.—Place iron (small tacks) in dilute sulphuric
acid, accelerating the action by heat until effervescence ceases.
a + ao ag Sees ior cis : Hydrogen
The solution contains ferrous sulphate, and will yield crys-
tals of that substance, FeSO, 7H,O, ( Ferri Su/phas, U.S. P.),
on cooling or on further evaporation; or if the hot con-
centrated solution be poured into alcohol, the mixture being
well-stirred, the sulphate is at once thrown down in minute
erystals (Ferri Sulphas Granulatus, U.S. P.). At a tem-
perature of 212°F. (100°C.), ferrous sulphate loses six-
sevenths of its water, and becomes Ferri Sulphas Exsiceatus,
U.8. P.
Other Sources af Ferrous Sulphate.—In the laboratory, ferrous
mite is often obtained as a by-product in making hydrogen
sulphide (p. 100). In the manufacture of alum it occurs as a by-
product in the decomposition of the aluminous shale, as already
noticed (p, 146),
152 THE METALLIC RADICALS.
A ten percent. solution of ferrous sulphate in distilled water
which has been previously boiled, constitutes ‘‘ Ferrous Sulphate
Test Solution,” U.S. P. *‘ This solution should be freshly pre-
pared immediately before use,’’ because of its liability to absorb
oxygen with formation of ferric oxysulphate (see below).
Notes.—Ferrous sulphate was formerly termed green vitriol,
Vitriol (from vidrum, glass) was originally the name of any trans-
parent crystalline substance: it was afterward restricted to the
sulphates of zinc, iron and copper, which were, and still are ocea-
sionally, known as white, green and blue vitriol respectively.
Copperas (probably originally Copper-rust, a term applied to ver-
digris and other green incrustations of copper) is another name
for this iron sulphate, sometimes distinguished as green copperas,
copper sulphate being blue copperas, Exsiccated ferrous sulphate
is a constituent of Pilula Aloes et Ferri, U.S, P. Ferrous sul-
phate forms a light green double salt with ammonium sulphate
(ammonium ferrous sulphate, (NH,),,50,, FeSO,, 6H,0).
Ferrous sulphate, when exposed to the air, gradually becomes
brown through absorption of oxygen, ferric oxysulphate,
Fe,QO(SO,),, being formed. The latter is not completely dis-
solved but is decomposed by water, with the formation of a still
lower insoluble oxysalt (Fe,O.80,), and soluble ferric sulphate:
5Fe,O(SO,), = Fe,O,80, + 3Fe,(S80,),.
Iron heated with undiluted sulphuric acid yields sulphurous
anhydride and ferrous sulphate:
Fe + 2H,SO, = FeSO, + SO, + 2H,0
Ferrous Carbonate. Iron Carbonate.
Experiment 2.—To a hot solution of ferrous sulphate, in a
test-tube, add a solution of sodium bicarbonate, which has
been prepared with water at a temperature not exceeding
50° C.; a white precipitate of ferrous carbonate, FeCO,, is
produced which rapidly becomes light-green, bluish green, and
on standing for some time, reddish-brown, owing to absorption
of oxygen; carbonic anhydride is evolved, and ferrie oxyhy-
droxide is formed.
FeSO, + 2N,HCO, = FeCO, + NaSO, + H,O + CO,
Ferrous Sodium Ferrous Sodium Water Carbonic
sulphate bicarbonate carbonate sulphate anhydride
Saecharated Ferrous Carbonate.—The above precipitate of fer-
rous carbonate, rapidly washed with boiling distilled water, and
then mixed with sugar and quickly dried—all possible precautions
being taken to avoid prolonged exposure to air—forms saccharated
ferrous carbonate (Ferri Carbonas Saccharatua, U, 8, P.). This is
probably a mixture of ferrous carbonate, ete., with sugar; i com-
FERROUS SALTS. 153
pound known as iron sucrate, containing about 48.5 percent. of
iron, is obtained by pouring a solution of cane-sugar and ferric
chloride into a slight excess of sodium hydroxide; a reddish-brown
crystalline precipitate is produced. Jron ma/tosate is an analogous
nd.
ns —The red powder formerly termed Carbonate or Subcar-
honate of Tron (Ferri Carbonas or Ferri Subcarbonas) was ferrous
carbonate washed and dried with free exposure to air, the product
thus, by the absorption of oxygen and the elements of water, and
the elimination of carbonic anhydride, becoming ferric oxyhydrox-
ide, a compound which will come under notice subsequently,
Ferrous carbonate is said to be more easily dissolved in the
stomach than any other iron preparation. It so easily oxidized,
that it must be washed with water free from dissolved air, and
then mixed with the sugar (which protects it from oxidation) us
quickly as cog ed In making the official compound mixture of
iron Joc A Ferri Cimposita, U, S, P.), ‘Griffith's mixture,’’
_ ingredients, including the potassium carbonate,
sboald tots be elieed | in a bottle of the required size, space being left
for the solution of ferrous sulphate, which should be added lust,
the bottle immediately filled up with the rose-water and sec urely
corked; the minimum of oxidation is thus ensured. The propor-
tions ordered in the official mixture are almost three times the for-
mula weight of potassium carbonate for once that of ferrous sul-
phate; hence, as the ferrous carbonate decomposes, the carbonic
anhydride produced does not necessarily escape, but converts the
potassium carbonate into bicarbonate. Pi/u/a Ferri Carbonatis,
U 8. P., Jron Pill or * Bland’s Pill,’’ is prepared with granulated
ferrous sulphate and potassium carbonate.
FeSO, + K,CO, = FeO, + K,SO,
Ferrous Arsenate. Iron Arsenate
See under Arsenic (p. 174).
Perrous Phosphate. Iron Phosphate.
Experiment 3.—To a hot solution of ferrous sulphate in a
test-tube add a hot solution of sodium phosphate and a small
quantity of a solution of sodium bicarbonate ; ferrous phos-
phate is precipitated.
_ BF SO, 2NaHPO, + 2NaHCO, =
- Ferroonmuate Stein hoaphate Sodium biearbonate
retro), + SNaS0O, + 2H,O + 200,
Sodium sulphate Water Carbonic anhydride
THE METALLIC RADICALS.
The addition of the sodium bicarbonate is to ensure the absence
of free sulphuric acid from the solution, Sulphuric acid dissolves
ferrous phosphate, and it is impossible to prevent the liberation
of some sulphuric acid, if only the ferrous sulphate and sodium
phosphate be employed without the sodium bicarbonate. Ferrous
phosphate is white but soon becomes oxidized and is then slate-
blue. It was formerly included in the United States Pharmaco-
peeia, and is still official in the British Pharmacopoia.
Ferrous Sulphide. Iron Sulphide.
Experiment 4.—Mix sulphur in a test-tube with about twice
its weight of iron filings and strongly heat the mixture in the
Bunsen flame (or heat in an earthen crucible in a furnace) ;
ferrous sulphide, Fes, is formed. When the product is cold,
add water to asmall portion of it, and then a few drops of
sulphuric acid ; hydrogen sulphide, H,S, recognizable hy its
odor, is evolved. FeS + H,SO, — FeSO, + HS.
Sticks of sulphur pressed against a white-hot bar of cast-iron
give a pure form of ferrous sulphide ; or melted sulphur may be
poured into a crucible of red-hot iron nails, when a quantity of
fluid ferrous sulphide is at once formed and may be poured out on
a slab,
Hydrous Ferrous Chloride. Iron Chloride.
Experiment 5,—Digest iron tacks or wire, in a test-tube, in
hydrochloric acid ; hydrogen escapes, and the solution on cool-
ing, or on evaporation and cooling, deposits crystallized ferrous
chloride, FeCl, 4H,O.
Anhydrous Ferrous Chloride.—See p. 156.
Ferrous Iodide. Iron Iodide.
Experiment 6.—Place a piece of iodine, about the size of a
pea, in a test-tube, with a small quantity of water, and add a
few iron filings, or small nails, or some iron wire. On gently
warming, or merely shaking if longer time be allowed, the
iodine disappears, and on filtering, a clear light-creen solution
of ferrous iodide, Fel,, is obtained. On evaporation, the
solid iodide remains.
Solid ferrous iodide contains about 18 percent, of water of erys-
tallization and a little iron oxide. It is deliquescent and liable to
absorb oxygen from the air with formation of insoluble ferric oxyie-
dide or hydroxyiodide, Ferrus iodide thus oxidized may be
FERRIC SALTS. 155
purified by re-solution in water, addition of a little more iodine
and some iron, warming, filtering, and evaporating as before,
Syrup of ferrous iodide (Syrupus Ferri Jodidi, U. 8. P.), has al-
ready been mentioned on p. 37. Syrup of ferrous iodide which
has become brown may usually be restored by immersing the
bottle in a water-bath and slowly warming,
In making Pi/ule Ferri Iodidi, U. 8, P., reduced iron (see. p.
162) is used.
_ Ferrous Bromide, FeBr,, occasionally used in medicines may
be made in a similar way. Its solution in water or syrup is light
green.
FERRIC SALTS.
Anhydrous Ferric Chloride. (Iron Perchloride).'
Experiment 7.—Pass chlorine (generated from black man-
ganese oxide and hydrochloric acid in a flask) through con-
centrated sulphuric acid contained in a small wash-bottle (to
dry the gas) and then, by means of a glass tube, to the bot-
Fra. 31.
Preparation fur anhydrous ferric chloride.
tom of a test-tube containing twenty or thirty small iron tacks
(or a flask containing two or three ounces of them—see Fig.
31), the latter being kept hot by a gas-flame; ferric chloride,
PeCl,, is formed and condenses in the upper part of the tube
* The prefix per (and hyper) used here and elsewhere is from iwip, hyper,
over, or above, and in this case, indicates the higher chloride of iron;
that fa, iron perchloride is the iron chloride which contains the larg er
proportion of chlorine.
156 THE METALLIC RADICALS.
or flask as a mass of small, dark, irredescent crystals, Whena
tolerably thick crust of the salt is formed, break off the part
of the glass containing it, being careful that the remaining cor-
roded tacks are excluded, and place it in ten to twenty times
its weight of water : the resulting solution, poured off from an
pieces of glass, is a nearly neutral solution of ferric chloride,
and may be employed for analytical reactions.
Precaution.—The above experiment must be conducted in the
open air, or in a fume-cupboard.
Anhydrous Ferrous Chloride.—In breaking up the vessel, sealy
crystals of this substance, FeCl,, of a light and bulf color, will be
observed adhering to the nails.
Note.—Solution of ferric chloride gives off some hydrochloric
acid on boiling, while a darker-colored solution of ferric oxy-
chloride remains.
Solution of Ferric Chloride.
Experiment 8, Through a portion of the solution of ferrous
chloride, prepared in experiment 5, pass chlorine gas; the
ferrous chloride is converted into ferric chloride, The excess
of chlorine dissolved by the liquid in this experiment may be
remoyed by ebullition; but the ferric ch loride is liable to be
slightly decomposed. (See above). The free chlorine is
better carried off by passing a current of air through the
liquid for some time,
Experiment 9. To a portion of the solution of ferrous
chloride, prepared in experiment 5, add a little hydrochloric
acid; heat the liquid, and drop in nitric acid until the black
color at first produced, disappears; the resulting reddish-
brown liquid is a solution of ferric chloride.
8FeCl, + HNO, + 3HCl = 3FeCl, + NO +2H,0
Ferrous Nitric Hydrochloric Ferric Nitric Water
chloride acid acid chloride oxide
The black substance is a compound produced by the interac-
tion of nitric oxide, NO, with some ferrous salt; its composition
is 2heSO,+-NO; it is decomposed by heat.
Liquor Ferri Chloridi, U. 8. P., is a solution of ferrie chloride
prepared by pouring a solution of ferrous chloride into a sufficient
quantity of nitric acid contained in a capacious vessel, evaporating
until the liquid is free from nitric acid, and adjusting the solution
so as to contain 10 percent. of iron. 1 volume with 3 of aleohol,
gives Jinelura Ferri Chloridi, U. 8, P.
Note, —The alcohol in the latter preparation does not act either
as a special solvent or as a preservative—the offices usually per-
ail
FERRIC SALTS. 157
formed by alcohol in U. 8. P. preparations—and, as a matter of
fact, unless the liquid contain excess of acid, it decomposes the
ferric chloride and canses the formation of an insoluble ferric oxy-
chloride. Even if the tincture be acid, it slowly loses color,
ferrous chloride and ethereal compounds containing chlorine being
formed. Liquor Ferri Chioridi is not liable to such decomposition
and such variation in characters,
Solution of Ferric Chloride, when evaporated, yields a mass of
yellow crystals having the composition FeCl,, 6H,O, or, under
other conditions, red crystals represented by the formula 2FeCl,,
5H,0.
Perric Sulphate (formerly called Iron Persulphate).!
Experiment 10.— Dissolve about three-quarters of an ounce
of ferrous sulphate and about a fifth of this weight of sulphuric
acid in an ounce and a half of water in an evaporating-dish,
heating the mixture and dropping in nitric acid until the
black color at first produced, disappears. The resulting
liquid, when made of a certain prescribed strength, is solution
of ferric sulphate (Liquor Tersulphatis, U. 8. P.), a heavy,
dark-red liquid.
pater est et SB (BO )s T acs r oie
sulphate acid avid sulphate oxide
The black color, as in experiment 9, is due the formation of a
compound by the interaction of ferrous salt with nitric oxide.
Ferric Hydroxide and Ferric Oxyhydroxide.
Experiment 11.—Pour a portion of the solution of ferric
sulphate into excess of ammonia water; ferric hydroxide,
Fe(OH),, Ferri Hydrovidum, U.S. P., is precipitated. Wash
the precipitate hy decantation or on a filter, and dry it on
a water-bath; ferric oxyhydroxide, FeOQ(OH), remains,
Pepe + 6NH.OH — 2Fe(OH), + 3(NH,,SO,
i
Ammonia Ferric Ammoniom
te water hydroxide sulphate
Fe(OH), — FeO(OH) + HO
Ferric hydroxide Ferric oxyhydrozide Water
_ Either of the other alkalies (caustic potash or soda) would pro-
duce a similar reaction.
' The name persulphate cannot now be applied consistently to this
The pers e form a definite series of salts derived from
‘ wei . Ferric sulphate is simply the sulphate cor-
res] ng to the higher basic oxide of iron —ferric oxide, FezO,, formerly
Seequioxide, and sometimes peroxide, of iron. |
158 THE METALLIC RADICALS.
Ferric hydroxide is an antidote in cases of arsenical poisoning,
if administered directly after the poison has been taken, It con-
verts the soluble arsenous acid, H,AsO,, into insoluble ferrous
arsenate :—
4Fe(OH), + 2H,AsO, = Fe,(AsO,), + 8H,0 + Fe(OH),
Ferric hydroxide becomes conyerted into oxyhydroxide, when
dried, and has then less action on the arsenous acid, — Even the
moist recently prepared hydroxide loses much of its action as soon
as it has changed into one of the oxyhydroxides, FeO(OH),, a
change which will occur though the hydroxide be kept under
water (W. Procter, jun.). According to T. and H. Smith, this
decomposition occurs gradually, but in an increasing ratio; so
that after four months the power of the moist mass is reduced to
one-half and after five months to one-fourth. :
A ferric oxycarbohydroxide, Fe,OCO,(OH),, has been obtained.
Ferric Oxide.
Ferric oxyhydroxide, FeO(OH), decomposes when heated
to low redness, ferric oxide, Fe,O,,remaining.
2FeQ(OH) — Fe,O, + H,O
Experiment. 12.—Roast a crystal or two of ferrous sulphate,
mixed with a small quantity of sulphur to aid the reduction,
in a small crucible until fumes are no longer evolved; the
residue is a variety of ferric oxide, known in trade as red
oxide of iron, coleothar, crocus, mineral rouge, Venetian red, ete.
It has sometimes been used in pharmacy in mistake for the
oxyhydroxides, from which it differs not only in composition
ay in the important respect of being almost insoluble in
acids.
Ferric Acetate. Iron Acetate.
Experiment 13,—Digest recently-prepared, washed, and
drained ferric hydroxide in glacial acetic acid; ferric acetate,
Fe(C,H,9, ),, 18 produced:—
Fe(OH), + 3HC,H,O, = Fe(C,H,0,), + 3H,0
Ferric hydroxide Acetic acid Ferric acetate Water
The “Scale"’ Compounds of Iron,
Experiment 14.—Repeat experiment 11, introducing some
solution of citric or tartaric acid or of potassium bitartrate
into the ferric sulphate solution before adding it to the alkali
FERRIC SALTS, 159
(caustic soda, caustic potash, or ammonia), and notice that
now no precipitation of ferric hydroxide occurs. The non-
production of precipitates is due to the formation of double
compounds, which remain in solution along with alkali-metal
sulphate. Such ferric compounds, made by mixing certain
prescribed proportions of recently prepared ferric hydroxide
(from which all soluble sulphate has been removed by wash-
ing), with the respective acids (tartaric or citric) or acid salts
( potassium bitartrate), etc., evaporating the solutions to a
syrupy consistence and then spreading on smooth plates to
ry, form scale preparations such as Ferri et Ammonii Citras,
u S, P., and Perri et Potassii Tartras, U.S. P. A mixture
of ferric citrate with ammonium citrate and quinine citrate
yields, by similar hee a the well-known scales of Ferri et
Quinine Citras, U. 5.
Specimens of these substances may be prepared by attending to
the following details, It is essential, first, that the ferric hydrox-
ide be thoroughly washed, or an insoluble oxysulphate will be
formed; secondly, that the ferric hydroxide be rapidly washed, or
ati insoluble ferric oxyhydroxide will be produced; thirdly, that
the whole operation be conducted quickly or reduction to green
ferrous salt will occur; fourthly, that the solutions of the salts be
not evaporated at a high temperature, or decompositon will take
place; and, fifthly, that excess of ferric hydroxide be employed.
In making the scale compounds, the ferric hydroxide is in each
ease freshly made from solution of ferric sulphate by precipitation
with ammonia water:—
Fe,(80,) + 6NH, + 6H,O = 2Fe(OH), + 8(NH,), 80,
Ammonia Ferric Ammonium
ceils water hydroxide sulphate
the solution of ferric sulphate being made of a definite concentra-
tion from a known weight of ferrous sulphate. The reason for
adopting this course is, that ferric hydroxide cannot be dried with-
out eat ace aoe and becoming insoluble as explained on p, 158,
cannot be weighed. This definite solution of ferric
sulphate (Liquor Ferri Tersulphatis, U.S. P.), is made as already
described,
Ferri ef Ammonii Citras, U. 8. P.—Ferric hydroxide is dis-
solved in solution of citric acid, ammonia water udded, and the
whole evaporated to dryness.
To prepare the ferric hydroxide, dilute 10 fluidounces of the
above solution of ferric sulphate with about a quart of water; pour
this into 2 pints of water containing excess of ammonia water.
(If the opposite course were adopted—the alk: aline liq uid poured
into the ferric ferric solution—the precipitate would pate rey ferric oxy-
160 THE METALLIC RADICALS.
sulphate, or hydroxysulphate, which interferes with the brilliancy
of the seales.) Thoroughly stir the mixture (it will smell strongly
of ammonia if enough of the latter has been used), allow the pre-
cipitate to subside, pour away the supernatant liquid, add more
water, and repeat the washing until a white precipitate of barium
sulphate is no longer produced on the addition of solution of ba-
rium chloride or nitrate to a little of the washings. Collect the
ferric hydroxide on a filter, drain, and add it, while still moist,
to asolution of 4 ounces of citric acid in 4 of water, placed in an
evaporating-basin on a water-bath; stir frequently, until nearly
the whole of the hydroxide hus dissolved, or until the acid is
fully saturated with the hydroxide and some of the latter remains
undissolved. To the mixture, when cold, add 54 fluidounces of
ammonia water, filter, evaporate on 4 water-bath to the consist-
ence of syrup, spread thinly on sheets of glass, and dry (at a
temperature not exceeding 100° F,, 37.8°C.). The product scales
off the glass in deep-red transparent laminz,
ote. —The chemical composition of iron and ammonium citrate
is approximately FeO(NH,),0,H,O,. Compounds which exhibit
an analogy in composition are found in bismuth and ammonium
citrate, BiO(NH,),C,H.O,, and antimony and potassium tartrate,
SbOKC,H,0O,.
Ferri et Quinine Citras Solubilis, U, 8. P.—Ferric hydroxide and
pure quinine are dissolved in solution of citric acid, ammonia
water adJed, and the whole evaporated to dryness. The product
contains ferric citrate, quinine citrate, and ammonium citrate,
The ferric hydroxide is obtained from 9 fluidownces of the
solution of ferric sulphate, with all the precautions described
under Ferri ef Ammonia Cilras,
While the ferric hydroxide is being washed, prepare the qui-
nine by dissolving 2 ounces of quinine bisulphate in 16 ounces of
distilled water, and to the clear liquid add ammonia water, well
mixing the product by stirring, until the whole of the quinine is
precipitated (this is the case when the mixture, after thorough
agitation, smells of ammonia), Collect the precipitate on a filter,
let it drain, and wash away adhering solution of ammonium sul-
phate by passing through it about three pints of distilled water.
The ferric hydroxide and quinine being now washed and
drained, dissolve the former, and afterward the latter, in a solu-
tion of 6 ounces and 60 grains of citric acid in an equal weightof
distilled water, the acid liquid being warmed on a water-bath, and
portions of the precipitates stirred in as fast as solution is effected.
Let the solution cool ; add, in small quantities at a time, 3 fluid-
ounces of ammonia water, diluted with 4 fluidounces of dis-
tilled water; stir briskly, allowing the quinine which separates
with each addition of ammonia to dissolve before the next addition
is made; filter the solution; evaporate it to the consistence of a
FERRIC SALTS. 161
thin syrup; dry the latter in thin layers on flat porcelain or glass
plates at a temperature of 100° F. (37.8° C,); remove the dry
scales of Soluble Iron and Quinine Citrate. Ferri et Quinine
Citras, U. 8. P., is a similar, but somewhat less readily soluble
jon,
. i ef Potassii Tartras, U. 8. P.—Ferric hydroxide is dis-
solved in solution of potassium bitartrate, and the whole evapo-
rated to dryness.
The ferric hydroxide obtainable from 10 fluidounces of the official
solution of ferric sulphate by the action of ammonia, in the
manner detailed under Ferri ef Ammonii Cifras, is mixed (in a
porcelain dish ), while still moist but well drained, with 3 ounces
and 146 grains of potassium bitartrate. The whole is set aside for
rai twenty-four hours, and then heated on a water-bath to a
not exceedin 140° F. (60° C.); a pint and a half of
distilled water is then added, and the mixture is kept warm until
Sothtae more will dissolve, filtered, evaporated at a temperature
not exceeding 140° F, (60° C. ), (greater heat causes decomposition),
and when the mixture has the consistence of syrup, spread on
sheets of glass and allowed to dry (i e any warm and open place at
a tem) re not exceeding 100° 37.8° C.). The dry salt is
thus o |in seales, It should be kept in M -cleeed bottles.
In the United States Pharmacopwia Ferri Citras, Ferri et Strych-
nine: Cifras, and Ferri ef Ammonii Tartras wre included. Ferric
citrate dissolves slowly in cold, but readily in warm water,
Ferrie phosphate, FePO,, when freshly precipitated, is soluble in
solutions of citrates of the alkali-metals, and the solutions on evapo-
ration on glass plates yield scales. Ferri Phosphas Solubilis,
U. 8, P., isa preparation of this kind : it may be obtained by the
interaction of sodium phosphate with a solution of ferric citrate
and evaporation of the solution at a temperature which should
not exceed 140° F. (60° C.). It forms thin, bright green trans-
ae. Ferri Pyrophosphas Solubilis is also official.
The foregoing are the official scale preparations of iron. Many
others of similar character might be formed. Few of them erys-
tallize or give other indications of definite chemical composition.
Their properties are only constant so long as they are made with
see decing prore ions of the constituents. A crystalline, ferrows
ros hg | Ct Ow and an acid ferrous citrate, FeHC, H,O,, H,O,
have podedyg a obtained by the interaction of iron and the respec-
tive acids in hot water. They occur as white gritty masses of
A sodio-ferrous citrate, FeNaC,H.O,, and
so pepe O,H,0,, may be obtained in scales,
" wine (Vinum Ferri, U. 8. P.), is a
pee ae Ammonium Citrate in white wine, with Tinc-
ae Peel and Syrup added. Bitter Wine of Iron
4
Amarum, U. 8. P.), is a similar solution of soluble
Quinine Citrate,
aed ~=
‘s
THE METALLIC RADICALS.
Ferric Nitrate.
Experiment 15.—Place a few iron tacks in dilute nitric acid
and set aside ; solution of ferric nitrate, Fe( NO,),, is formed.
Fe + 4HNO, = Fe(NO,), + 2H,O + NO
Iron Nitric neil Ferric nitrate Waler Nitric oxide
Ferric nitrate and ferric acetate unite to form various aceto-
nitrates, among which is one having the formula Fe,(C,H,O,),
NO OH, 4H,0, and crystallizing in hard, shining brownish-red
prisms.
| Reduced Iron,
Experiment 16.—Pass pure hydrogen (which has been dried
by passing it over pieces of calcium chloride contained in a
tube or through sulphuric acid in a wash-bottle) over a smal]
quantity of ferric oxide, Fe,O,, or ferric oxyhydroxide,
F 1a, 32.
Preparation of reduced iron.
Fe(OH), contained in a tube placed horizontally, the powder
being kept hot by a gas-flame; oxygen is removed by the
hydrogen, steam escapes at the open end of the tube, and after a
short time, when moisture ceases to be evolved, metallic iron,
in a state of fine division, remains. (See Fig. 52.)
— 2FeO(OH) + 3H, = 2Fe + 4
Ferric o xvyhydroxide Hydrogen Iron Water
While still hot, throw the iron out into the air; it takes fire
and falls to the ground as magnetic oxide, Fes Ji
If ferric oxide is reduced in no strongly-heated iron tube in a
furnace, the particles of iron aggregate to some extent, and,
REDUCED IRON, 163
when cold, are only slowly oxidized in dry air. This latter form
of reduced iron is Fer réduit, or Quevenne’s Iron, the Ferri pulvic,
or Ferrum Reductum, U. 8. P.—‘‘a very fine grayish-black lustre-
less powder, without odor or taste.’’ It is often administered
in the form of a lozenge, gum and sugar protecting the iron from
oxidation as well as forming a vehicle for its administration.
Note. 1—The spontaneous ignition of the iron in the above
experiment is an illustration of the influence of minute division on
the occurrence of chemical change, The action is the same as
that which occurs when iron wire burns (as it does with great
brilliancy) in oxygen, The surface exposed to the action of re
oxygen of the air is, in the case of this variety of reduced iron,
enormous compared with the weight of the iron, that the feak ie is
not conducted away sufficiently fast to prevent ‘elevation of tem-
perature to a point at which the whole becomes incandescent.
The mixture of lead and carbon (lead pyrophorus) resulting when
lead tartrate is carefully heated in a test-tube until fumes cease to
be evolved, spontaneously ignites when thrown into the air, and
for the same reason. Many substances, solid and liquid, if liable
to oxidation, and sufficiently finely divided, and especially if ex-
posed in a warm place, become hot and even occasionally burst
into flame spontaneously. Oil on cotton waste, powdered char-
coal, coal leaakelally if pyritic, porous, or powdered), resins in
der, and even flour and hay, are familiar illustrations of
materials liable to ‘“‘heat,’’ or char, or even burn spontaneously.
Note 2.—The student who has time and opportunity to do so,
is advised to carry out experiment 16, as a roughly quantitative
one, by way of realizing what has already been stated (see Lawa
Combination, pp. 51, 52), with respect to chemical
actions, that they take place between definite weights only of
matter. Three tubes, similar to the oxide tube shown in Fig, 32
(or three U tubes), should be prepared, the second being con-
nected to the first, and the third to the second, in the usual man-
ner by means of India-rubber tubing. The first tube should con-
tain pieces of calcium chloride to absorb any traces of moisture
not retained by the sulphuric acid. The second tube (the ends
of the small tube being temporarily closed by small corks) should
be weighed in a balance which wil! turn with a quarter of or half
a grain, and, the weight having been noted, 159 grains of dry
ferric oxide should be neatly placed in the ‘niddle of the tube.
(The oxide, before being weighed must be heated in a small
erucible over a Bunsen flame to convert any ferric oxy hydroxide
into ferric oxide, and to remove all traces of moisture), T he third
tube should contain pieces of calcium chloride to absorb the wate r
produced in the reaction, and should be we ighed just before being
connected. The operation is now ci arricd out, ‘At its lose and
when the middle tube is cold, the latter and the third tube : are
again weighed. The oxide tube should w eigh nei arly 48 (47 a)
164 THE METALLIC RADICALS.
grains less than before, and the calcium chloride tube nearly 54
(53.64) grains more than before.
FeO, + = 2Fe + 3H,O
(111+4-47.64)+ 6 = lll + 58.64
The operation is completed more quickly if one-half or one-fourth
of the weight of the oxide being taken; in that case one-half or
one-fourth of the weights of iron and of water will be obtained.
Indeed any weight of oxide may be employed; the amount of iron
and water resulting will be always exactly proportionate to the
weights just mentioned, provided the whole of the ferric oxides
is reduced to iron,
Analytical Reactions of Iron Salts,
Reactions of Ferrous Salts,
1. Pass hydrogen sulphide, H,S, through a solution of a
ferrous salt (e.g., ferrous sulphate) slightly acidulated with
hydrochloric acid ; no precipitate is produced. This is a
valuable negative fact, as will be evident presently,
2. Add ammonium hydrosulphide, NHSH, to solution of
a ferrous salt; a black precipitate of ferrous sulphide, Fe,
is produced,
FeSO, + 2NH SH = FeS + (NH,)50, + HS
3. Add solution of potassium ferrocyanide (yellow prus-
siate of potash), K,FeC,N., to a solution of a ferrous salt; a
pale blue precipitate is produced, which rapidly becomes
darker blue owing to absorption of oxygen and conversion
into Prussian blue. (See p. 165.)
4. To a solution of a ferrous salt add potassium ferricyan-
ide (red prussiate of potash) K,FeC,N,; a dark blue preeipi-
tate is produced of Turnbull’s blue, resembling Prussian blue.
Other Analytical Reactions.—The precipitates produced
from ferrous solutions on the addition of alkali-metal carbon-
ates, phosphates, and arsenates as already described in the
experiments dealing with the preparation of the corresponding
ferrous salts, are characteristic, and hence have a certain
amount of analytical interest, but are inferior in this respect
to the four reactions above mentioned,
Cyanogen (CN, or Cy"), forrocyanogen (FeCgNe’*', or FeCye’”") and
ferricyanogen (FeCeNo'’, or FoCys"'’) are radicals which play the part of
non-metallic cloments, just asammonium in itschemical relations resem-
bles the wetallic elements. They will be referred to agnin.
FERROUS SALTS. 160
Note,—Solution of ammonia, and solutions of caustic potash
and soda in presence of ammonium salts, are incomplete precipi-
tants of ferrous salts. To a solution of a ferrous salt add ammo-
nia; on filtering off the whitish ferrous hydroxide, and testing the
filtrate with ammonium hydrosulphide, iron will still be found
in solution. To another portion of the ferrous solution add afew
drops of nitric acid, or excess of chlorine water, and boil; this
converts the ferrous into ferric salt, and alkalies, including ammo-
nia, will now precipitate the iron completely as ferric hydroxide.
In actual analysis, the separation of iron as ferric hydroxide is
an operation of frequent performances. This is always accomp-
lished by the addition of alkali after (if the iron occurs as a fer-
rous salt) previous ebullition with a little nitric acid. Potassium
ferrocyanide and ferricyanide are the reagents most commonly used
in distinguishing ferrous from ferric salts.
Reactions of Ferric Salts.
1. Through a solution of a ferric salt (¢.g., ferric chloride)
pass hydrogen sulphide; a white precipitate of sulphur (from
the hydrogen sulphide), is produced. The ferric salt is
simultaneously converted into a ferrous salt, the latter remain-
ing in solution. This reaction is of frequent occurrence in
analysis :—2FeCl, + H,S = 2FeCl, 4+ 2HCI + 8.
2, Add ammonium hydrosulphide to a solution of a ferric
salt; the latter is reduced to the ferrous state, and a black
substance (ferrous sulphide, FeS) is precipitated as in the
second analytical reaction of ferrous salts, sulphur being set free.
3. To a solution of a ferric salt add potassium ferrocyanide,
K.FeC,N,; a precipitate of Prussian blue (the well-known
pigment), is produced.
4. Toa a ai of a ferric salt add potassium ferricyanide ;
no precipitate is produced, but the liquid assumes a dark
brownish red color (or a greenish olive hue if the salts are
not quite pure).
5. Add sodium hydroxide or ammonia water to a solution
of a ferric salt; a reddish-brown precipitate of ferric hydrox-
ide, Fe(OH),, is produced (compare experiment 11, p. 157).
- Other Analytical Reacti
tions.—Some of these have occasional
interest. In neutral ferric solutions the tannic acid in aqueous
infusion of galls occasions a bluish-black inky precipitate,
the basis of most black writing inks.—Potassium thiocyanate,
4 N, causes the formation of ferric thiocyanate, which is
of a deep blood-red color. The color disappears on the addi-
tion of mercuric chloride.
166 THE METALLIC RADICALS.
There is no normal ferric carbonate; alkali-metal earhon-
ates cause the precipitation of ferric hydroxycarbonate while
earbonic anhydride escapes.
QUESTIONS AND EXERCISES,
Name the chief ores of iron.—How is the metal obtained from the ores?
—What is the chemical difference between cast-iron, wrought-iron, and
steel ?—Explain the process of “welding.”—What is the nature of chaly-
beate waters ?—Illustrate by formulw the difference between ferrous and
ferric salts.—Write a paragraph on the nomenclature of iron salts.—Give a
diagram of the process for the preparation of ferrous sulphate.—In what
respocts do the official Ferrous Sulphate and Exsiccated Ferrous Sulphate
differ ?—How is ferrous sulphate obtained on the large seale ?—Give the
chemical names of white, green and blue vitriols—Why does ferrous sul-
phate become brown on exposure to air ?—Represent by an equation the
formation of Ferrous Carbonate.— Describe the action of atmospheric oxy-
gen on ferrous carbonate; can the effect be prevented ?—In what order
would you mix the ingredients of Mistura Ferri Composita, and why ?—
Name four iron compounds which may be formed by the direct union of
their clements.—Give the official method for the preparation of Solution
of Ferric Chloride.— How may Ferrous be converted into Ferric Sulphate ?
—Whiat is the formulaof Ferric Acetate, and how is it prepared )—How
does Ferric Hydroxide act as an antidote in arsenical poisoning ?—What
are the properties of ferric oxide ?—What are the general characters and
mode of production of the medicinal scale preparations of iron ?—Give a
diagram showing the formation of Ferric Nitrate.—Calculate how much
ferric oxide will yield, theoretically, one hundredweight of iron, Ana.
160 Ibs., approximately '—Describe the action of each of the following re-
agents on solutions of iron salts, distinguishing between ferrousand ferric
reactions, and illustrating each of the reactions by an equation ;—a. Am-
monium hydrosulphide. 6, Potassium ferrocyanide, ¢, Potassium ferri-
eyanide. «d. Caustic Alkalies. ¢. Potassinm thiocyanate,—Describe the
action of ammonia water on salts of iron, aluminiom and zinc respec-
tively.
CHROMIUM: Cr. Atomic weight, 51.7.
Occurrence, —T he chief ore of chromium is chrome ironstone,
FeO,Cr,0,, chromite, occurring chiefly in the United States and
in Sweden, The metal may be isolated by the action of alumi-
nium on chromic oxide, € 0), at a very high temperature,
Chromiam forms sets of salts corresponding to chromous and
chromic oxides, CrO and Cr,O, respectively, but the chromous
sults are exceedingly readily converted by processes of oxidation
into chromic salts, and can only be prepared and preserved with
difficulty, The ordinary salts in which chromium plays the part
of the metallic radical, are the chromic salts, such as chromic
chloride, CrCl,; chromic sulphate, Cr,(80,),; ete, Chromium
also forms an acid anhydride, chromic ‘anhydride, CrO,, and the
best known chromium compounds—the chromates (e.g., potassium
CHROMIUM. 167
chromate, K,CrO,), and the dichromates or anhydrochromates
(¢.9., potassium dichromate, K,CrO,,, CrO, or K,Cr,O,) in which
the chromium forms a part of the complex acid radicals CrO,”
and Cr,O.”—are referred to the unknown chromic acid [H,CrO,]
and anhydrochromic acid [H,Cr,O,], corresponding to this anhy-
dride. Most of the commoner chromium compounds are obtained
from potassium dichromate.
Preparation of Potassium Dichromate.—On roasting powdered
chrome iron ore with potassium carbonate and nitrate, yellow
potassium chromate, K,CrO,, is obtained; the mass, treated with
acid, yields red potassium dichromate, K,CrO,, CrO,, or K,Cr,0,
(Potaasti Dichromas, U. 8. P.) :—
2K,CrO, + 2HCl = K,Cr,O, + 2KC] + H,O
From this, other chromates are prepared, and, by reduction, as
presently explained, the chromic salts,
Heated strongly in a crucible, potassium dichromate splits up into
potassium chromate, glistening green chromic oxide, and oxygen,
4K,Cr,0, = 4K,Cr0, + 2Cr,0; + 30, Ammonium dichromate,
when heated yields several times its volume of bluish-green chromic
oxide, water, and nitrogen. (NH,),Cr,O, = Cr,O, -+- 4H,0 + N,.
The yellow and orange lead chromates (lead chromate PbCrO,, and
basic lead chromate, Pb,OCrO,), are used as pigments.
Potassium Chromate,—The normal or yellow potassium chromate
is obtained on adding potassium bicarbonate, 200 grains, in small
ities at a time, to a hot solution of the dichromate, about
5 grains, until effervescence ceases.
K,0r,0, + 2KHCO, = 2K,CrO, + 200, + H,O
For analytical purposes solution of a normal chromate is still
more readily prepared by simply adding ammonia water to a
solution of potassium dichromate, until the liquid turns yellow
and, after stirring, smells of ammonia,
K,0r,0, + 2NH,OH = K,CrO, + (NH,),CrO, + H,O
Conversion of a chromate (in which ehromium forms part of
an acid radical) into a chromic salt (in which chromium ia the
metallic radical).—Through an acidulated solution of potassium
dichromate pass hydrogen sulphide: sulphur is deposited, and
a n chromic salt remains in solution—chromic chloride,
PCL, if hydrochloric acid be used, and sulphate, Cr,(SO,),,
if sulphuric be the acid employed. Boil the liquid to expel
excess of hydrogen sulphide, filter, and reserve the solution
for # vent experiments. (For an equation representing
thie r ace p. 168). Alcohol, sugar, and various other
THE METALLIC RADICALS.
substances which are moderately easily oxidized answer as
well as hydrogen sulphide. For a method of carrying out
ihe reverse operation to that just described, «. ¢, the conyer-
sion of a chromic salt into a chromate, see the dry-way
reaction for chromium compounds in general on p. 170,
Chromic sulphate, Cr,(SO,)s, like aluminium sulphate, Al,(SO,),,
unites with alkali-metal sulphates to form double salts which are
called alums, These alums resemble common alum in crystalline
form; but they do not contain aluminium, the place of the latter
being taken by chromium: they are of a purple color,
Chromic Anhydride,
Experiment,— Mix four volumes ofa cold saturated aqueous
solution of potassium dichromate with five of sulphuric acid ;
on cooling, chromic anhydride often called chromic acid, CrO,,
(Chromii Trioxidum, U.S. P.), separates in crimson needles.
After well draining, the crystals may be freed from adhering
sulphuric acid by washing once or twice with nitric acid: the
latter may be removed by passing dried and slightly warmed
air through a tube containing the crystals. Chromic anhy-
dride may also be freed from sulphuric acid by one or two
recrystallizations. In contact with moisture, chromic anhy-
dride takes up water and forms a solution of anhydroechromic
acid [H,Cr,O,]. Chromic anhydride is a powerfully corrosive
oxidizing agent; it melts between 356° and 374° F, (180° to
190° C.), and at a higher temperature decomposes, yielding
chromic oxide and oxygen; it oxidizes organie matter with
great violence, spontaneous ignition sometimes resulting.
In the systematic analytical examination of solutions contain-
ing chromates, the chromium is precipitated as green chromic
hydroxide along with ferric and aluminium hydroxides, the prior
treatment with hydrogen sulphide in presence of hydrochloric
acid reducing the chromate to the condition of a chromic salt,
thus:—
2K,Cr,0, + 16HCI + 6H,S = 4CrCl, + 4KC] + 14H,0 + 38,
Chromium having been found in a solution, its condition as chro-
mate may be ascertained by noting the yellow or orange color of
the solution; by observing the precipitation of sulphur, as above,
with simultaneous change in color from orange to green when the
acidulated solution is treated with excess of hydrogen sulphide;
and by applying to the solution, salts of barium, mercury, lead,
and silver. (See the various paragraphs relating to those metals).
CHROMIUM.
Bevo gives yellow BaCrO, with chromates,
HgNO, ~ red Hg,Cr0, ¥
AgNO, « red Ag,CrO
NO, red Ag-Cr,O, with dichromates.
Ag ,
Pb(C,H,0,), *s yellow PbUrO, with both,
Barium nitrate does not completely precipitate dichromates,
barium dichromate being soluble in water; barium chromate is
insoluble in water and in acetic acid, but soluble in hydrochloric
or nitric acid. Mercurous nitrate does not wholly precipitate
dichromates : mercuric nitrate or chloride only partially precipi-
tates chromates, and cloes not precipitate dichromates. Mercurous
chromate is insoluble, or nearly so, in dilute nitric acid. Silver
chromate and dichromate are soluble in acids and alkalies. Lead
acetate precipitates lead chromate from bofh chromates and di-
chromates, acetic acid being set free in the latter case (K,Cr,O,+
2Pb(C,H,0,), + H,O = 2PbCrO, + 2KC,H,O, + 2HC,H,O,).
A delicate reaction for dry chromates depends on the
formation of chromyl chloride or echlorochromie anhydride,
CrO,Cl,, A small portion of the chromate is placed in a test-
tube with a fragment of dry sodium chloride and a drop or
two of sulphuric acid, and the mixture is heated; red irrita-
ting fumes of chlorochromic anhydride are evolved, and con-
dense in dark red drops on the side of the tube,
Larger quantities are obtained by the same reaction, the opera-
tion being conducted in a retort, with thoroughly dry materials,
as the com d is decomposed by water. Chlorochromic anhy-
dride may be regarded as chromic anhydride in which an atom of
( is displaced by an equivalent quantity (two atoms) of
ehlodinvs: Tt is not used in medicine, but is of interest to the
student as an example of a class of compounds known as aci-
chlorides, The reaction is also occasionally serviceable for the
detection of chlorides.
Analytical Reactions of Chromic Salts,
1. To a solution of a chromic salt (chloride, sulphate or
chrome alum) add ammonium hydrosulphide ; a bulky green
precipitate of chromic hydroxide, Cr(OH),, is produced.
CrCl, + 8NH,SH + 3H,0 = Cr(OH), + 3NH,Cl + 38H,8
2. To a solution of a chromic salt, add ammonia water ;
green chromic hydroxide is precipitated, insoluble in excess.
3. To a solution of a chromic salt, add solution of sodium
or potassium hydroxide drop by drop; green chromic hy-
droxide is precipitated. Add excess of the alkali; the pre-
_
THE METALLIC RADICALS.
cipitate is dissolved. Boil the solution for some time; chro-
mic hydroxide is reprecipitated.
Chromic Oxyhydroxides.—Intermediate in composition between
chromic hydroxide, Cr(OH),, and chromic oxide, Cr,O,, two oxy-
hydroxides are known, namely, Cr,O(OH), and CrOOH.
Dry-way Reaction for Chromium Compounds in general.—
Mix a small quantity of any chromium compound with sodium
carbonate and a few grains of nitre on platinum foil, and fuse
the mixture in the blow pipe-flame ; a yellow mass (potassium
and sodium chromates) is formed. Dissolve the mass in
water, add acetic acid to decompose excess of carbonate, and
apply the reagents for chromates. This is a delicate and use-
ful reaction if carefully performed.
The production of the chromate from a chromic salt in the
above reaction may be represented by the equation :—
2CrCl; + HNa,CO, + 830 = 2Na,CrO, + 6NaCl + 5CO,,
DIRECTIONS FOR APPLYING THE ANALYTICAL REACTIONS DE-
SCRIBED IN THE FOREGOING PARAGRAPHS TO THE ANALYSIS
OF AN AQUEOUS SOLUTION OF SALTS CONTAINING ONE OF
THE METALS, ALUMINIUM, TRON, CHROMIUM.!
First note the color of the solution :—
Solutions of aluminium salts are colorless,
Solutions of ferrous salts are colorless or pale green.
Solutions of ferric salts are yellow or brownish.
Solutions of chromic salts are bluish-purple or green.
Add ammonia water (the group rengent) gradually : :—-
A white precipitate, insoluble or nearly so in excess, indi-
sates an aluminium salt,
A dirty-green precipitate indicates iron in the state of a
ferrous salt.
A reddish-brown precipitate indicates iron in the state of a
ferric salt.
' The analytical behavior of chromium in the chromic salts is alone re-
ferred to here. In the systematic examination of solutions for other
metallic radicals besides those hitherto considered, any chromate or
dichromate originally present is converted into chromic salt before the
stage is reached at which aluminium, iron, and chromium are tested for,
(Note, however, that solutions of chromates and dichromates are yellow
and orange respectively.
QUALITATIVE ANALYSIS. 171
A bluish-grey precipitate, insoluble or nearly so in excess,
indicates a chromic salt,
These results may be confirmed by the application of some
of the other tests to fresh portions of the solution.
TABLE OF SHORT DIRECTIONS FOR APPLYING THE ANALYTICAL
REACTIONS DESCRIBED IN THE FOREGOING PARAGRAPHS TO
THE ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF ONE,
TWO, OR ALL THREE OF THE METALS, ALUMINIUM, IRON,
_—— es
CHROMIDTM.
Boil about one-third of a test-tubeful of the solution with a
few drops of nitric acid. This ensures the conversion of ferrous
into ferric salt, and enables the next reagent (ammonia) com-
pletely to precipitate the iron. Add a slight excess of ammo-
nia water and shake the mixture ; filter. Wash the precipi-
tate, dry it, and fuse it on platinum foil with sodium carbonate
and potassium nitrate. Boil the fused mass in water, and filter,
Residue. Filtrate.
Fe.0 If yellow, Cr is present and has formed chromate
7s during the fusion. Divide into two parts.
brown
(Note 1) I dere
Add NH,Cl and Add acetie acid in excess
warm. White ppt. in- | and AgNO, Red ppt. in-
dicates Al. dicates Cr,
— Sd — = ——— ee
Note 1.—If iron is present, portions of the original solution
must be tested with potassium ferricyanide for ferrous, and with
potassium ferrocyanide for ferric salts; dark-blue precipitates indi-
ente ferrous and ferric salis respectively.
Note 2.—If ferrous salt is not present, the preliminary ebul-
lition with nitric acid is unnecessary, It is perhaps therefore
advisable always to determine this point previously by testing a
little of the original solution with potassium ferricyanide ; if no
blue precipitate is produced, the nitric acid treatment may be
omitted.
Cerium; Ce. At. wt., 139.2—This element occurs in the
mineral cerite (which contains iron, calcium, and the rare metals,
cerium, lanthanum, and didymium [the latter really a mixture of
neodymium and praseodymium] as silicates); ‘also occ asionally
as impure fluoride, carbonate, and phosphate. The oxalate, Cerit
172 THE METALLIC RADICALS.
Oxrdas, U. 5. P., a white granular powder, is the only official
salt ; it may be obtained from cerite by boiling the powdered
mineral in concentrated hydrochloric acid for several hours, evap-
orating, diluting and filtering to separate silica; adding ammo-
nia water to precipitate hydroxides of all the metals ex eal-
cium; filtering, washing, redissolving in hydrochloric acid, and
adding oxalic acid to precipitate cerium oxalate. The pre
tion still contains lanthanum and didymium oxalates ; it is
fore strongly calcined, the resulting lanthanum and didymium
oxides dissolved out to some extent by boiling with a concentrated
solution of ammonium chloride, the residual cerium oxide dis-
solved in boiling hydrochloric acid, and ammonium oxalate added
to precipitate cerium oxalate, Ce,(C,O,)s, 9H,O. According to «
Hartley, the precipitated hydroxides should be treated with
chlorine, by which ceric hydroxide is left insoluble and the other
hydroxides converted into soluble hypochlorites,
The oxalate is insoluble in water. It is decomposed at a dull-
red heat, 47 percent. of a yellow or, generally, salmon-colored
mixture of oxides remaining. Usually ‘the didymium present gives
the ignited residue a reddish or reddish-brown color. The oxides
are soluble in boiling hydrochloric acid (without effervescence, in-
dicating, indirectly, absence of earthly and other carbonates or
oxalates); and the solution gives, with excess of a saturated solu-
tion of potassium sulphate, a crystalline precipitate of double
cerium and potassium sulphate. Aluminia mixed with cerium
oxalate may be detected by boiling with solution of
hydroxide, filtering, and adding excess of solution of ammonium
chloride, when a white flocculent precipitate (aluminium hydrox-
ide) will be obtained. The oxalic radical is recognized by neutral-
izing the potassium hydroxide solution with acetic acid, and add-
ing calcium chloride; a white precipitate (calcium oxalate) falls :
this precipitate, though insoluble in acetic acid, should be wholly
soluble in hydrochloric acid. Acid or neutral cerium solutions
give with sodium acetate and hydrogen peroxide a brownish-red
color (Hartley).
QUESTIONS AND EXERCISES,
State the method of preparation of potassium dichromate.—Give the
formule of potassium chromate and dichromate. — How is potassium chro-
mate obtained ?—Describe the action of hydrogen sulphide on acidulated
solutions of chromates.—What is the formula of chrome alum ?—Mention
the chief tests for chromates and for chromic salts. —What are
and properties of cerium oxalate ?
ARSENIC and ANTIMONY.
These elements, especially antimony, resemble metals in ap-
pearance and in the character of some of their compounds; but
they are still more closely allied to the non-metals phosphorus
ARSENIC AND ANTIMONY, 173
and nitrogen, with which they form anatural group. The hydro-
n compounds of the four members of this group are represented
by the formulz NH,, PH,, AsH,, SbH,. <A few preparations of
arsenic and antimony are used in medicine; but all are more or
less powerful poisons, and hence have toxicological interest.
From observations of the vapor density of arsenic, it would
appear that the molecule of arsenic contains four atoms, and that
its formula is As, At temperatures above 1700° C, the vapor
density corresponds to the formula As,.
From observed analogy between the two elements, the molecu-
lar constitution of antimony is probably similar to that of arsenic.
Vapor density determinations, moreover, lead to the formule
As,O, and 8b,0, for arsenous and antimonous oxides (the formula
As,O, has been adopted in the U. 5. P.).
ARSENIC: As. Atomic weight, 74.4.
Occurrence, ete.—Arsenical ores are frequently met with in
nature, the commonest being iron arseno-sulphide, FeAsS. This
‘‘mispickel’’ is roasted in a current of air, the oxygen of which,
combining with the arsenic, forms common white arsenic ‘‘arsenic'’)
or arsenic trioxide, sometimes called anhydrous arsenous acid, or
better, arsenows anhydride, As,O,, (Arseni Trioridum, U. 8. P.),
which is condensed in chambers or long flues. It commonly
occurs as a heavy, white, opaque powder, or in masses which
usually present a stratified appearence caused by the presence, in
separate layers, of the crystalline and opaque and of the amor-
phous and vitreous allotropic modifications. The vitreous or amor-
phous oxide is far more soluble than the crystalline variety, and
the two kinds exhibit other differences in properties, Such dif-
ferences between the crystalline and amorphous varieties of an
element or compound or between two crystalline varieties are not
infrequent. Realgar — algar) is mative red arsenic sulphide,
AsS,, and orpiment (auripigmentum, the golden pigment), is
native yellow sulphide, AsS.. Arsenous iodide, Asl,, (Arseni
lodidum, U.5.P.), may be made from its elements or by dissolv-
ing white arsenic in aqueous hydriodic acid and evaporating the
solution, It occurs in small orange-colored crystals, or crystal-
line masses, soluble with partial decomposition in water and in
aleohol, Its aqueous solution affords the reactions characteristic
of arsenic and of iodides, and is neutral to litmus. Heated in a
test-tube, it almost entirely volatilizes, violet vapors of iodine
being set free. Ebullition with much water gives rise to the
formation of a basic salt, A solution of 1 part by weight of
arsenous iodide and 1 part by weight of mercuric iodide in 100
fluid of water, forma Liquor Arseni ef Hydrargyri Jodidi,
U.S. P. (Dovonan’s Solution).
174 THE METALLIC RADICALS,
Alkaline Solution of Arsenic.
Experiment 1.—Boil a grain or two of powdered white
arsenic, As,O,, in a solution of potassium bicarbonate and filter
if necessary. The solution, colored with compound tincture
of lavender, and containing 1 part by weight of As,O, in 100
fluid parts, forms Liquor Potassii Arsenitis U.S. P. ‘(ho wler’s
Solution ).
Arsenous Acid and other Arsenites.
White arsenic, or arsenous anhydride, As,O, (formerly called
arsenous acid), when dissolved in water yields a solution which
contains some arsenous acid, H,AsQ,, hydrogen arsenite, and
possesses a faintly acid reaction.
AsO, + 6H,O = £4H,As0
Arsenous auhy dride Water Arse nous me la
When arsenous anhydride is dissolved in solutions of potassium
or sodium hydroxide, the anhydride being used in excess, the so-
called acid arsenites, KH(As0,), and NaH (AsQ,),, are formed,
Boiled for some time with excess of the respective alkali-metal
carbonates, these salts yield other arsenites (really metaresenites,
as the acid salts also are) the composition of which is represented
by the formule KAsO, and NaAs0,,.
Arsenous anhydride fused with alkali-metal carbonates yields
pyroarsenates (Na, As,O, or K,As,O,, as the case may be) and
metallic arsenic,
Acid Solution of Arsenic.
Experiment 2.— [oil arsenous anhydride with dilute hydro-
chloric acid; the anhydride slowly dissolves. Such a solution
made with prescribed proportions of acid and water, and con-
taining 1 part by weight of As,O, in 100 fluid parts, forms
Liquor Acidi Arsenisi U.S. P. (De Valangin’s Solution con-
tains a grain and a half per ounce, )
Nole—The student should also boil arsenous anhydride in
water only, and thus have an acid, an alkaline, and an aqueous
ursenous solution for analytical comparison,
Arsenic.
Experiment 3.—Place a grain or less of arsenous anhy-
dride at the bottom of a narrow test-tube, cover it with half
an inch or so of amall fragments of dry charcoal, and hold
the tube, nearly horizontally, in a Bunsen flame, the mouth
ARSENIC. 17d
of the tube being loosely covered by the thumb. At first let
the hottom of the tube project slightly beyond the flame, so
that the charcoal may become nearly red-hot; then heat the
bottom of the tube. The oxide will volatilize, become deoxi-
dized by the hot charcoal, carbonie anhydride being formed,
and the element arsenic (formerly sometimes termed «arseni-
cum), will be deposited in the cooler part of the tube as a dark
mirror-like metallic coating. During the operation a charac-
teristic odor, resembling garlic, is emitted.
Metallic arsenie may be obtained in large quantities by the above
process if the operation be conducted in vessels of appropriate
size. Performed on the small scale with great care, in narrow
tubes, and using not charcoal alone, but black flux (a mixture of char-
coal and potassium carbonate obtained by heating acid potassium
tartrate in a test-tube or other closed vessel till no more fumes
are evolved), the reaction has considerable analytical interest, the
garlic odor and the formation of the mirror-like ring being highly
characteristic of arsenic. Compounds of mercury and antimony,
however, give sublimates which resemble arsenic in appearance
and must not be mistaken for it,
Arsenic Acid and other Arsenates.
4.—Boil a grain or two of arsenous anhydride
with a few drops of nitric acid until red fumes are no longer
evolyed; evaporate the solution to dryness in a small dish,
to remove excess of nitric acid; dissolve the residue in water:
the product is Arsenic Acid, H,AsO..
Arsenic acid, when strongly heated, loses the elements of water,
and arsenic anhydride, As,O,, remains. At a still higher tempera-
ture arsenic anhydride decomposes, yielding arsenous anhydride
and oxygen. | ,
Arsenic anhydride readily absorbs water and becomes arsenic
acid, H,AsO,. Arsenic acid is reduced to arsenous acid by the
action of sulphurous acid. *H,AsO,+ HSO,—H,AsO, + HS0,.
Salts derived from arsenic acid are termed arsenates, The
di-ammonium arsenate, (NH,),HAsO,,may be made by neutrali-
ving arsenic acid with ammonia. [ts solution in water is occasion-
ally used at a reagent in analysis, Arsenic acid is used as an
oxidizing agent in the manufacture of the well-known dye,
_,- *.
’ ta.
py rte arsenite and arsenate are used in the cleansing opera-
: : ae a
tions of the calico-printer.
176 THE METALLIC RADICALS.
Sodium Arsenate and Pyroarsenate.
Experiment 5.—Fuse 2 or 3 grains of arsenous anhydride,
As,O,, with sodium nitrate, NaNO,, and dried sodium earbon-
ate, Na, CO,, in a porcelain crucible, and dissolve the result-
ing mass of sodium pyroarsenate in water; solution of sodium
arsenate, Na,HAsQ,, results.
As,O,+4NaNO, + 2Na,CO, = 2Na,As 0,-42N, 0,+-200,
Arsenous Sodium Sodium ~ Sodium Nitrous Curbonie
anhydride nitrate carbonate pyroarsenate anhydride anhydride
Na,As,O, + H,O = 2Na,HAsO,
Sodium pyroarsenate Water Sodium arsenate
Crystallized from the solution and dried, a salt is obtained which is
represented by the formula Na,HAsO,, TH,O. (Sodii Arsenas,
U. 5. P.)
The anhydrous salt, Na, HAs0,, obtained by exposing to a tem-
perature of 302° F (150° C.), crystallized sodium arsenate, is
official (Sodii Arsenas Exeic catus, U. S. P.). A 1 percent.
aqueous solution forms Liquor Sodii Arsenatis, U. 8. P. It has
about half the arsenical strength of Liguor Potassti Arsenitis,
U.5. P. The anhydrous salt is used because the crystallized salt
is of somewhat uncertain composition, The fresh erystals are
represented by the formula Na,HAsO,, 12H,O (=53.7 percent.
of water); these soon effloresce and yield a stable salt having the
formula Na,HAsO,, 7H,O (= 40.4 percent. of water). To avoid
the possible employment of a mixture of these salts, the anhydrous
salt, of uniform composition, is alone official.
The student will find nseful practice in verifying, by calculation, the
above numbers representing the centesimal proportion of water in the
two sodium arsenates.
The crystalline form of each variety of sodium arsenate
(Na,HAsO,, 12H,O, and Na,HAsO,, 7H,0) is identical with that
of the corresponding sodium phosphate (Na, HPO,, 12H,0, a and
Na,HPO,, 7H,Q), the pairs of analogous composition being iso-
morphous, This is only one instance of the strong analogy of
arsenic and its compounds with phosphorous and its correspond-
ing compounds, The preparations and characters of the next
substance, ferrous arsenate, will remind the student of ferrous
phosphate.
Ferrous Arsenate. Iron Arsenate.
Experiment 6.—To a hot solution of sodium arsenate add
n hot solution of ferrous sulphate and a small quantity of a
solution of sodium bicarbonate; a precipitate of ferrous arsen-
ate, Fe(AsO,),, is produced, On a larger scale, 26) parts
ARSENIC. 177
of dried sodium arsenate dissolyed in 100 of hot water, and
20% of ferrous in 120 of hot water, with 44 of sodium bicar-
bonate, may be employed. The precipitate should be col-
lected on a calico filter, washed, squeezed, and dried on a
water-bath, at a low temperature (100° F., 37.8° C.) to avoid
excessive oxidation. It is ferrous arsenate, Fe,( AsO, ),, 6H,O,
with ferric arsenate and some iron oxide.
2Na HAsO, + 2NaHCO, + 3FeSO, =
Sodium arsenate Sodium bicarbonate Ferrous sulphate
Fe,(AsO,), + 3NaSO0O, + 2H,O + 2CO
Ferrous arsenate Sodium sulphate Water Carbonic anhydride
The use of the sodium bicarbonate is to ensure the absence of
free sulphuric acid from the solution. This acid dissolves ferrous
arsenate, and it is impossible to prevent its liberation if only the
ferrous sulphate and sodium arsenate be employed without the
sodiam bicarbonate. .
At the instant of precipitation ferrous arsenate is white, but it
rapidly becomes of a green or greenish-blue color owing to absorp-
tion of oxygen and formation of a ferrosoferric arsenate. When
dry, it is a tasteless, amorphous powder which is soluble in acids
and has undergone oxidation to a considerable extent.
Arsenic Hydride and Sulphides, and Copper and Silver Arsenites
and Arsenates are mentioned in the following analytical paragraphs.
. Analytical Reactions of Arsenic Compounds.
1. Repeat experiment 3, operating on not very much more
arsenous anhydride than the size of a small pin’s head, and
using not charcoal alone, but the black flux already mentioned,
or a well-made and perfectly dry mixture of charcoal and
Fis, 33,
potassium carbonate (the latter salt best obtained by heating
potassium bicarbonate). The tube employed should be a
narrow test-tube, or better, a tube (easily made from glaas-
tubing) having the form ( Berzelius’s) shown in Fig. 33.
The oxide and black flux are placed in the bulb of the
tube, which is then heated in a Bunsen flame; the arsenic
condenses on the constricted portion of the tube. If now the
bulb be carefully removed by fusing and drawing out the
glass, the arsenic may be chased up and down the narrower
4
178 THE METALLIC RADICALS.
part of the tube until the air in the tube has re-oxidized it to
arsenous anhydride.
If the operation has been performed in a less delicate man-
ner in an ordinary test-tube, cut or break off portions of the
tube containing the sublimate of arsenic, put them into a test-
tube and heat the bottom of the latter, holding it nearly hori-
zontally, and partially closing the mouth of the tube with the
finger or thumb; the arsenic combines with oxygen from the
air in the tube, and the resulting arsenous anhydride is
deposited on the cool part of the tube in brilliant, generally
imperfect, octahedral crystals.
Octahedron. A sublimate of arsenons anhy-
dride (Magnified).
Microscopic Examination.—Prove that the crystals are
identical in form with those of arsenous anhydride, by heating
a grain or less of the latter in another test-tube and examin-
ing the two sublimates by means of a good lens or a compound
microscope.
The appearance of a sublimate of arsenous anhydride is
peculiar and quite characteristic. The primary form of each
erystal is an octahedron (¢«ro, okto, eight; @pa, hedra, side)
(Fig. 34a), or, rarely, a tetrahedron, and in a sublimate a
few perfect octahedra are generally present. Usually, how-
ever, the crystals are modifications of octahedra such as are
shown in Fig. 34—which is drawn from actual sublimates,
2. Reinsch's Test.—Place a piece of copper foil, about }
inch wide and 4 inch long, in a solution containing arsenic
and hydrochloric acid, and boil (nitric acid must not be
present, or the piece of metal will be dissolved); arsenic is
leposited on the copper as a gray coating possessing a some-
what metallic appearance. (Memorandum.—An equivalent
proportion of copper goes into solution. The experiment
forms an illustration of a kind of chemical change appropriately
ARSENIC, 179
termed substitution.) Pour off the supernatant liquid from the
copper,-wash the latter with water, dry it by means of a piece
of ter-paper, and finally place it at the bottom of a clean,
dry, narrow test-tube, or a Berzelius tube, and sublime as
described in reaction 1, again noticing the form of the result-
ing crystals. The tube containing the sublimate may be
reserved for subsequent comparison with a similarly obtained
sublimate of antimonious oxide. This test for arsenic was
introduced by Reinsch, in 1543,
Note.—Copper itself frequently contains arsenic, a fact that
may not, perhaps, cause any trouble to the student, who is per-
forming experiments in practical chemistry with known substances,
for educational purposes; but when the analyst proceeds to the
examination of substances of unknown composition, he must
assure himself that neither his apparatus nor materials already
contain the element for which he is searching.
The detection of arsenic in metallic copper is best accomplished
by boiling, in a retort or distilling-flask, a mixture of a few grains
of the sample with five or six times its weight of ferric hydroxide
or chloride (free from arsenic) and excess of hydrochloride acid.
The arsenic is thus volatilized in the form of chloride, and may
be condensed in water and detected by means of hydrogen sul-
phide (see reaction 6, p. 183) or by Reinsch’s test. The ferric
chloride solution is, if etree freed from any trace of arsenic
evaporating once or twice to dryness with excess of hydro-
acid.
Fre, 35.
The hydrogen test for arsenic.
3. The Hydrogen Test or Marsh's Test.—Generate hydrogen
in the usual way hy the interaction of zinc and dilute ‘sul- -
acid, a bottle of about four of six ounces ¢ capac ity
mene and a funnel-tube and short delivery-tube passing
through the cork as shown in Fig. 35. ‘Dry the esci eaping
180 THE METALLIC RADICALS.
hydrogen (except in rough experiments, when this is scarcely
necessary ) by adapting to the delivery-tube a short piece of
wider tubing filled with fragments of dried calcium chloride
(a). To the other end of the drying-tube fit a piece of
narrow tubing ten or twelye inches long, made of hard glass,
and having its outlet end reduced to a small bore by drawing
it out in the flame of the blowpipe. When the hydrogen has
heen escaping for a sufficient number of minutes and at such
a rate as to warrant the student in concluding that a// the air
originally present in the bottle has been expelled, kindle the jet,
and then pour eight or ten drops of the aqueous arsenical
solution, or three or four drops of the acid or alkaline solution
previously prepared, into the funnel-tube, washing the liquid
into the generating-bottle by means of a little water. By the
action of the zine and sulphuric acid, the arsenous compound
is reduced to the state of arsenic, and the latter combines with
some of the hydrogen to form arseniuretted hydrogen, or
hydrogen arsenide, AsH,,
AsO, + 12H = As, + 6H,0
Arsenous Hydrogen Arsenic Water
anhydride (nascent)
As, + 12H = 4AsH,
Arsenic Hydrogen Hy n
(nascent) arsenide
Hold a piece of glazed earthenware or porcelain (the lid
of a porcelain crucible (/) if at hand) in the burning hydro-
ven jet; a brown spot of arsenic is deposited on the cold sur-
face. Collect several of these deposits, and retain them for
future comparison with antimony deposits similarly obtained.
.To ensure the conversion of the whole of the arsenie into
hydrogen arsenide, it is advisable, toward the end of the
operation, to add a few drops of solution of stannous chloride
in hydrochlorie acid to the generating-flask ; this causes the
precipitation of the arsenic in a state of very fine division, in
which it is readily acted upon by the nascent hydrogen,
The separation of arsenic in the flame is due to the decomposi-
tion of the hydrogen arsenide by the heat. The cool porcelain at
once condenses the arsenic, and thus prevents its oxidation to
arsenous anhydride (which would otherwise take place at the
outer edge of the flame).
Hold a small beaker (c), or wide test-tube, over the flame
for a few minutes ; a white film of arsenous anhydride, AsO,
ARSENIO. 181
will be deposited slowly, and may be further examined in
contrast with the similarly produced film of antimonous oxide.
During these experiments the effect produced by the burnin
of the h -
ydrogen arsenide on the color of the hydrogen flame
should be noted ; the flame acquires a characteristic dull, livid,
bluish tint.
Apply the flame of a gas-lamp to the middle of the hard
lass delivery-tube (d, Fig. 35); the hydrogen arsenide is
ecomposed as before, but the liberated arsenic condenses in
the cool part of the tube, beyond the flamé, as a dark metallic
mirror. The tube may be removed and kept for comparison
with antimony deposit.
Note 1.—The zine and sulphuric acid used for Marsh’s test
must be free from arsenic. Zinc, like copper, frequently contains
arsenic as impurity. When « specimen, free from arsenic, is met
with, it should be reserved for analytical experiments. Sulphuric
acid, free from arsenic, can usually be purchased, but samples
must always be tested as to their purity.
Note 2.—In delicate and important applications of Marsh's
test, magnesium may be substituted for zinc with safety, arsenic
not being found in magnesium. Magnesium in rods is convenient
for this Both magnesium and zinc, if perfectly pure,
interact with acids extremely slowly; but the addition of a very
small quantity of chloroplatinic acid, at once promotes an abun-
dant evolution of hydrogen. Platinum, however, has a tendency
to hold back arsenic. According to Dyer, rod zinc has a similar
tendency, while granulated zinc at once gives hydrogen arsenide,
Note 3.—Sulphurie acid, which is often used for drying gases,
decomposes hydrogen arsenide, Calcium chloride is the appro-
priate desiccating agent for this gas.
Note 4.—The original apparatus proposed by Marsh, in 1836,
was a U-shaped tube, one limb of which was short, and closed by
as , 80 that-the whole of a small quantity of hydrogen
; could be collected, and afterward examined at leisure.
Note 5:—On account of the exceedingly poisonous character of
arsenide, the preceding test and the next one should be
conducted in a well-ventilated fume-cupboard.
4, Fieitmann’s Test.—Generate hydrogen by heating a
concentrated solution of sodium or potassium hydroxide and
ie of zinc in a test-tube, to nearthe boiling point (Zn +-
2N =H,+Na,Zn0,, see p. 157). Add a drop of arsenical
solution, Now spread over the mouth of the tube a cap of
filter-paper moistened with one drop of solution of silver nitrate.
182 THE METALLIC RADICALS,
Again heat the tube, taking care that the liquid itself shall
not spurt up on to the cap. A plug of cotton wool may
even be placed in the mouth of the test-tube to arrest this
spurting. The arsenical compound is reduced to arsenic,
which unites with the hydrogen, as in Marsh’s test; and the
hydrogen arsenide passing up through the cap interacts with
the silver nitrate, producing a purplish-black spot (of silver).
AsH, + 3H,O + 6AgNO, = H,AsO, + 6HNO, + 6Ag.
Note 1,—This reaction is valuable, since it enables the analyst
quickly to distinguish arsenic in the presence of antimony, During
the reduction of an antimony compound by nascent hydrogen
in an acid solution, a portion of the antimony is converted into
hydrogen antimonide, SbH,, which also acts upon silver nitrate;
whereas if the reduction is carried out in an alkaline solution,
hydrogen antimonide is not formed, and hence the effect just
described is not produced.
Note 2.—Aluminium answers as well as zine for Fleitmann’s
test (Gatehouse), or magnesium may be used; or instead of zinc
and alkali, sodium amalgam containing only a small porportion
of sodium may be employed (Davy).
Note 3.—If the filter-paper cap is moistened with solution of
mercuric chloride and then exposed to the action of hydrogen
arsenide, a yellow stain, AsHHg,Cl,, results ; becoming after a
time brown, AsHg,Cl,, and then black, As,Hg,.
The formation of a yellow stain when hydrogen arsenide, in
small quantity, interacts with mercuric chloride (see Note 3, above)
has been made the basis of a modification, elaborately described in
the U. 8. P., of Gutzeit’s test for arsenic. The student is advised
to consult the pharmacopeia for minute details of the precautions
necessary in employing the test in the examination of chemicals,
generally, for traces of arsenic. |
5, Bettendorff's Test.—To a solution of stannous chloride
in concentrated hydrochloric acid add a very small quantity
of any arsenical solution. Arsenic then separates, especially
on the application of heat, producing a yellowish and then
brownish color, a grayish-brown turbidity, or even a sediment
of gray-brown flocks, according to the quantity present. Much
water prevents the reaction, and its presence must therefore
be avoided as far as possible; indeed a liquid saturated with
hydrochloric acid gas gives the best results. The presence of
arsenic in sulphuric or hydrochlorie acid, or in tartar emetic,
ete., may be detected by means of this test. Nitrates, such
as bismuth oxynitrate, must first be heated with sulphurie acid
ARSENIC.
to remove the nitric acid radical before applying this test for
arsenic. The stannous salt is converted into stannic salt
during the reaction.
The foregoing are the most important reactions of arsenic,
whether existing in the arsenous or arsenic condition; of the
following reactions 10 and 11 may be employed to distinguish
arsenous and arsenic compounds from each other.
6. Through an acidulated arsenous solution pass hydrogen
sulphide: a yellow precipitate of arsenous sulphide, As.S,, is
at once produced. Add an alkali-metal hydroxide or hydro-
sulphide to a portion of the precipitate; it readilly dissolves.
The precipitate consequently would not be produced on pass-
ing hydrogen sulphide through an alkaline arsenous solution.
When arsenous sulphide is dissolved in a solution of a hydro-
sulphide, a soluble meta-thiarsenite (@eiov, fheion, sulphur) is
produced. Thus when ammonia hydrosulphide is used the solu-
tion contains meta-thiarsenite—
As,S, + 2NH,HS = 2NH,As8, + H,S
When a hydroxide is used, a mixture of metarsenite and meta-
thiarsenite is obtained—
2As8, + 4NaOH = NaAsO, + 3NaAsS, + 2H,O
To another portion of the arsenous sulphide precipitate,
well drained, add concentrated hydrochloric acid ; it is insol-
uble—unlike antimonous sulphide. (Neither sulphide is sol-
uble in dilute hydrochloric acid ).
Note 1.—A yellow sulphide is also produced in an acid solution
of a cadmium salt by the action of hydrogen sulphide, but this
sulphide is insoluble in alkaline liquids. Under certain circum-
stances tin, too, yields ayellow sulphide, but tin is otherwise
easil distinguished,
ole 2.—A trace of arsenous sulphide is sometimes met with in
the sulphur distilled from arsenical pyrites, It may be detected
by digesting the sulphur in ammonia water, filtering, and evapor-
ating to dryness; a yellow residue of arsenous sulphide is obtained
if that substance be present.
as ene an praninted solution of areeitio acid, or any
preci itation Sikes ae very ‘alow * in fatdealigiting, Beanner ar
and Tornicek state that by a slow current the arsenic ac sid is
rac | reduced to arsenous acid, and a yellow precipitate
is which consists of arsenous sul phide mixed wi th sul-
184 THE METALLIC RADICALS.
phur. The reaction is more rapid if the solution be warmed.
The precipitate is soluble in alkali-metal hydroxides and
hydrosulphides. When it is dissolved in a hydrosulphide
the solution contains a thiarsenate, while a hydroxide produces
a mixture of arsenate and thiarsenate.
8. To an aqueous solution of arsenous anhydride add two
or three drops of solution of cupric sulphate, and then
cautiously add dilute ammonia water, drop by drop, until
a green precipitate is obtained. The production of this
precipitate is characteristic. To a portion of the mixture add
an acid; the precipitate dissolves, To another portion add
an alkali; the precipitate dissolves. The solubility of the
precipitate in both acid and alkali shows the advantage of
testing a suspected arsenical solution by means of litmus-
paper before applying this reaction, and if found to be acid,
cautiously adding alkali, or if alkaline, adding acid, till
neutrality is obtained; or a special reagent—copper ammonio-
sulphate—may be used. (See note to reaction 11.)
The precipitate consists of cupric arsenite, CuHAsO,, or
Scheele’s Green. In the pure state, or mixed with cupric acetate
or, occasionally, with cupric carbonate, it is used as a pigment
under different names, such as Brunswick Green and Schwein-
furth Green, by painters and others.
9. Apply the test just described to a solution of arsenic
acid or other arsenate ; a somewhat similarly colored precipi-
tate of cupric arsenate is obtained.
10. Repeat reaction 8, substituting silver nitrate for cupric
sulphate: in this case a yellow precipitate of silyer arsenite,
Ag, AsO,, is produced, also soluble in acids and alkalies.
11. Apply the silver nitrate test of the preceding reaction
to a solution of arsenic acid or other arsenate; a brown
precipitate of silver arsenate, Ag, AsQ,, is formed.
Copper and Silver Reagents for Areenic.—The \ast four reactions
may be performed with increased delicacy and certainty of result
if the copper and silver reagents be previously prepared in the
following manner:—To cupric sulphate (test-solution) add ammo-
nia water until the blue precipitate at first formed is nearly,
but not quite, redissolved ; filter and use the liquid as an arsenic
reagent, labeling it Cupric Ammonium Sulphate Test-Solution
(U. 8. P.). Treat solution of silver nitrate (about 1 part in 20)
in the same way, and lInbel it Silver Ammonium Nitrate Test-
Solution (U.S. P.). The composition of these two salts will be
referred to subsequently.
ARSENIC. 185
Arsenous and Arsenic Compounds.—While many reagents
may be used for the detection of arsenic, only the behavior
with silver nitrate will immediately and distinctly indicate in
which state the arsenic exists; for the two sulphides and the
two copper precipitates, though differing in composition, resem-
ble each other in appearance, whereas the two silver precipitates
differ in color as well as in composition.
Soluble arsenates give precipitates of insoluble arsenates on
the addition of solutions of salts of barium, calcium, zine,
Arsenic, when it exists as arsenic acid or other arsenate,
does not rapidly respond to the test with hydrogen sulphide
or nascent hydrogen. Hence, if its presence, as arsenate, is
MAS» the liquid under examination should be warmed
with a little sulphurous acid—or treated with hydrochloric
acid until slightly acid and then with solution of sodium thio-
sulphate—before the addition of hydrogen sulphide.
Antidote in Cases of Arsenical Poisoning —The most
effective antidote in these cases is recently precipitated moist
ferric hydroxide, administered as soon as possible. It is
pete best administered in the form of the mixture obtained
y adding magnesia ( Magnesii Oxidum, U.S. P.), previously
rubbed up to a smooth, thin mixture with cold water, to a dilute
solution of ferric sulphate (one part of Liquor Ferri Tersul-
phatia, U. 5. P., to about three of water). This arsenic
antidote (Ferri Hydroxidum eum Magnesii Oxido) is official.
Emeties should also be given, and the stomach-pump, or a
common India-rubber tube, used as a siphon, be applied as
quickly as possible.
The above statements regarding the antidote for arsenical poison-
ing may be Verified by mixing the various substances together,
filtering, and proving the absence of arsenic in the filtrate by
ipplying some of the foregoing tests.
le af Action of the Antidote. —The action of the magnesia is
Meso. itate ferric hydroxide, Fe(OH),—magnesium sulphate,
Mgs File formed, which is at least harmless, if not beneficial,
under the circumstances. The interaction between ferric hydrox-
ide and arsenous acid results in the formation of insoluble ferrous
arsenate, (See also p, 158.)
186 THE METALLIC RADICALS,
QUESTIONS AND EXERCISES.
What is the formula of a molecule of arsenic?—In what form does
arsenic occur in nature?— Deseribe the characters of white arsenic.
Name the official preparations of arsenic.—By what method may white
arsenic be redu to metallic arsenic?—Give the formulw of arsenous
and arsenic acids and anhydrides.—Explain, by equations, the reactions
which occur in converting white arsenic into sodium arseunte.—Why is
anhydrous instead of crystallized sodium arsenate employed officially ?—
Describe the manipulations necessary to obtain white arsenic in its chor-
acteristic crystalline form,—How is Reinsch’s test for arsenic applied, and
under what circumstances may its indications be fallacious }—Give the
details of Marsh's test for arsenic, and the precautions to be observed,
Explain the reactions by diagrams,—What peculiar value has Fleitmann’s
test for arsenic ?— Describe the conditions under which hydrogen sulphide
becomes a trustworthy test for arsenic.—How may a trace of arsenous
sulphide be detected in sulphur ?—How are salts of copper and silver
applied as reagents for the detection of arsenic?—How are arsenites
distinguished from arsenates?—Mention the best antidote in cases of
arsenical poisoning ; describe the process by which it may be most quickly
prepared, and explain its action.
=
ANTIMONY: Sb (Stibium). Atomic weight, 119.3.
Occurrence, ete.—Antimony occurs in nature chiefly as anti-
monious sulphide, Sb,S,, stibnite. The crude or black antimony
of pharmacy is this native sulphide freed from impurities by
fusion; it has a striated, crystalline, lustrous fracture; subsequently
powdered and, if it contains any soluble salt of arsenic, the latter
removed by digestion in ammonia water, it forms the grayish-
black crystalline purified black antimony, The metal is obtained
from the sulphide by roasting, the resulting oxide being reduced
with chareoal and sodium carbonate. The resulting seoria is
known as crocus of antimony or glass of antimony. Antimony is
also obtained from the native sulphide by heating it with iron,
ferrous sulphide being formed at the same time. Metallic anti-
mony is an important constituent of type-mefal, Britannia metal,
and the best varieties of pewter. The old pocu/a emetica, or ever-
lasting emetic cups, were made of antimony; wine kept in them
for 1 day or two was said to have acquired an emetic quality.
Antimony has very close chemical analogies with arsenic, Like
arsenic, it unites with iodine to form a tri-iodide (Sb). A
bromide, SbBr,, also is known.
Antimonious and Antimonic Chlorides.
Experiment 1.—Boil about half an ounce of antimonionus
sulphide with four or five times its weight of hydrochloric
acid in a dish placed in a fume-cupboard or in the open-air;
hydrogen sulphide ts evolved and solution of antimonious
chloride, SbCl, is obtained,
ANTIMONY.
tmnt + 6HCl = 2bCl + ee
— onious Hydrochloric Antimonious Grogan
acid chloride rite
This solution, cleared by subsidence, is what is commonly
known as butter of antimony. If pure sulphide has been used in
its preparation, the liquid is nearly colorless; but much of that
met with in veterinary pharmacy is simply a by-product in the
generation of hydrogen sulphide from native ferruginous anti-
monious sulphide and hydrochloric acid, and is more or less
brown from the presence of ferric chloride. It not infrequently
darkens in color on keeping; this is due to absorption of oxygen’
from the air, and conversion of light-colored ferrous into dark-
brown ferric chloride or oxychloride, It is a powerful caustic.
True butter of antimony, SbCl,, is obtained on evaporating
the above solution to a small volume, and distilling the residue.
The butter condenses as a white crystalline semi-transparent mass
in the neck of the retort ; at the close of the operation it may be
melted and allowed to flow into a bottle, which should be well
stoppered, It is highly corrosive.
Antimony pentachloride or antimonic chloride, SbC\,, is a fuming
liquid, obtained by passing chlorine over the trichloride,
Antimonious Oxychloride.
Experiment 2.—Boil the solution of antimonious chloride
produced in experiment 1, and pour it into several ounces
of water; a white precipitate of antimonious oxychloride,
Sb,O,Cl,, is produced, some antimonious chloride remaining
in the supernatant acid liquid.
Pict recipitate is the substance formerly known as pu/vis
lgarothi, pulvis angelicus, or mercuriua vile, It varies somewhat
in ‘com ition, according to the amount of water with which the
chloride may be mixed ; but, on standing under water, gradually
becomes crystalline, and has the composition given above.
45bCl, + 5H,O — Sb,0,Cl, + 10HCI
Antimonious Water Antimonious Hydrochloric
chloride oxychloride acid
Antimonious Oxide.
3,.—Wash the precipitate obtained in experi-
ment 2, thoroughly with water, by decantation (see p. J ll 6 )y
and add solution of sodium carbonate; the oxychloride | is
seahorse and antimonious oxide, Sh, O,, ‘is produced, ‘The
a light buff or eray ish-white color, or quite w hite if
absolutely free from iron, insoluble in water, soluble in hydro-
188 THE METALLIC RADICALS,
chloric acid, fusible at a low red heat. The moist antimonious
oxide may be well washed and employed for experiment 4, or it
may be dried ona water-bath. At temperatures aboye 212° F,
(100° C.), it absorbs oxygen and other antimony oxides are
formed. The presence of the latter may be detected on boil-
ing the powder in solution of acid potassium tartrate, in which
antimonious oxide, Sb,O,, is soluble, but antimonie anhydride,
Sb,O, and antimony tetroxide, Sb,O, or 8b,O, (8b,O,, 5b,0,),
are insoluble.
Sb,0,Cl, + Na,cCO, = Sb,O, + 2NaCl + CO,
Antimonious Sodium Antimonious Sodium hic
oxychloride carbonate oxide ehloride auhydride
The higher antimony oxide, 8b, O,, termed antimonie oxide or
anhydride, corresponding to arsenic anhydride, is obtained by
decomposing the pentachloride with water, or by boiling metallic
antimony with nitric acid. The variety obtained from the chloride
differs in saturating power from that obtained from the metal, and
is termed metantimonic acid.
Tartar Emetic.
Experiment 4.—Mix the moist antimonious oxide obtained
in experiment 3, with about an equal quantity of potassium
bitartrate (6 parts of the latter to 5 of the dry oxide) and suffi-
cient water to forma paste; set aside for a day to facilitate com-
plete combination; boil the product with water, and filter; the
resulting liquid contains antimony and potassium tartrate,
tartarated antimony, or tartar emetic(emetic, from énéw, emed,
I vomit) KSbOC,H,0O,.
4KHC,H,O, + Sb,0, = 4KSbOC,H,O, + 2H,0
Acid A ta se him Tartar emetie Water
%: ro
On evaporation, the salt is obtained in colorless transparent
erystals. These contain water of crystallization, and are
represented by the formula [K(SbO)C,H,O,],, H,O Ante
monii et Potassii Tartraa, U. 8. P.
Tartar emetic is very commonly represented (as above) as
potassium antimony! tartrate (SbO’= antimonyl), It seems almost
certain, however, that it is really the potassium salt of tartranti-
monious acid, HSbC,H,O,, in which antimony is present as a
part of the acid radical, A solution of this acid (which is very
unstable), also the barium and several other salts, have been
obtained,
ANTIMONY. 189
Tartar emetic is soluble in water, and slightly so in 60 per-
cent. alcohol.’ A solution in alcohol and white wine forms the
official Vinum Antimonii, U. 8, P.
Sulphurated Antimony and other Antimony
Oxysulphides.
Experiment 5.—Boil a few grains of antimonious sulphide
and of sulphur with sodium hydroxide solution in a test-tube,
and filter (or on a larger scale, 10 ounces of antimonious sul-
phide, 10 of sulphur, and 5 of sodium hydroxide for 2 hours,
frequently stirring, and occasionally replacing water lost by
evaporation). Into the filtrate, while still hot, stir dilute sul-
phurie acid until the liquid is slightly acid to test-paper; an
orange-red precipitate is produced. It is a mixture of anti-
mony pentasulphide, 5b,5,, with some oxide (S8b,O,, or pos-
sibly Sb,O,) and some free sulphur. The oxide results from
e interaction of antimonious sulphide and sodium hydroxide
in the presence of air.
This is one of the many varieties of mineral hermes, so-called
from their similarity in color to the insect Lermes. Kermes is the
name, now obsolete, of the Cocews Jlicis, a sort of cochineal-insect,
full of reddish juice, and used since the earliest times for dyeing.
The term mineral kermes was apparently applied originally to the
amorphous or precipitated orange antimonious sulpide, 8b,8,. It
afterward included any mixture of this with oxysulphide and
pentasulphide, A brownish-red variety may be prepared without
the addition of any free sulphur; the color of the precipitate is
then affected by the temperature as well as by the state of dilution
of the alkaline liquid when the acid is added. When this
alkaline liquid is boiled in contact with air, oxygen is absorbed
and unites with some of the antimony, displacing sulphur which,
in tarn, converts some antimony trisulphide into pentasulphide,
Kermes may be formed by fusion as well as by boiling the com-
ponents in aqueous solution.
of processes, —The antimony sulphides and oxides,
like those of arsenic interact with the sulphides and hydroxides of
certain metals to form salts which are more or less soluble in water.
Thus when antimonious sulphide is dissolved in hot solution of
sodium hydroxide, sodium metantimonite, NaSbO,, and meta-
thiantimonite, NaSbS,, are formed: in the presence of sulphur,
sodium metantimonate, NaSbO,, and sodium thiantimonate are
produced, the former of which is sparingly soluble.
2sbs, + aeeOR = Na8bO, 4- SNaSbS, + 2H,O
odium- odium Water
bedrovide Saidattennica meti- ihfaotinionite
190 THE METALLIC RADICALS.
4Sb8, + 88 + 18NaOH = 3NaSbO, + 5NaSbS, + 91,0
Antimonious Sulphur ‘Sodium Sodium Sodium Water
sulphide hydroxide metantimonate thiantimonate
The salts so formed in hot solutions are not all stable in cold solu-
tions, and antimony oxides, or sulphides, or both, are deposited
when the hot solutions cool. Thus sodium meta-thiantimonite
decomposes yielding sodium ortho-thiantimonite, NajSbS,, and a
deposit of antimonius sulphide, Sb,S,:
8NaSbS, = Na,SbS, + 8b,S,
In the preparation of kermes, therefore, the acid should be added
to the solution obtained on boiling up the necessary ingredients,
before any precipitate has separated (that is, before the solution
is cool), if uniformity of product is desired,
2NaSbS, + HSO, = Na,SO, + Sb,S, + HS
Sodinm meta- Sulphuric Sodium Antimonious ae
thiantimonite acid sulphate sulphide sulphide
4NaSbO, + 2H,SO, = 2Na,8O, + Sb,O, + 2H,0
Sodium Sulphurie Sodimm Antimontous Water
metantimonite acid sulphate oxide
ape ct So SH SO, = sNa SO, + Sb
Sodium Sulpburie Sodium Antinvoanic
thiantimonate acl sulphate sulphide
2NaSbO, + H,SO, = NaSO, + 8b,O, +
Sodium Sulphuric *« Sodium Antimonic Wa
metantimonate acid sulphate oxide
The oxides and sulphides indicated in these equations, are all
precipitated when the acid is added, and form the varieties of
Kermes,
Analytical Reactions of Antimonious Salts.
1. Through an acidified antimonious solution pass hydro-
gen sulphide; an orange precipitate of amorphous antimonious
sulphide, Sb,8,, is produced, It has the same composition as
the crystalline black sulphide into which, indeed, when dried,
it is quickly converted by heat. Like arsenous sulphide, it
is soluble in solutions of alkali-metal hydrosulphides and
hydroxides. Collect a portion on a filter and, when well
drained, add concentrated hydrochloric acid; it dissolyes—
unlike arsenous sulphide. _
Antimonic sulphide, Sb,S,, corresponding to arsenic sul-
phide, As,S,, is known. It is formed on passing hydrogen
sulphide through an acidulated solution of antimonie chloride,
SbCl, or, less pure, on boiling black antimonious sulphide
and sulphur with a caustic alkali, and decomposing the result-
ing filtered liquid by means of an acid.
ANTIMONY. 191
2. Dilute two or three drops of a solution of antimonious
chloride with water ; a white precipitate of antimonious oxy-
chloride is produced (see experiment 2, p. 187). The pro-
duction of a precipitate in these circumstances, distinguishes
antimony from arsenic, but the reaction is not capable of being
applied as a delicate discriminating test in analysis. Add a
sufficient quantity of hydrochloric acid to dissolye the precipi-
tate, and boil a piece of copper in the solution, as directed in
the corresponding test for arsenic (reaction 2, p. 178); anti-
mony is deposited on the copper. Wash, dry, and heat the
copper in a test-tube as there described ; the antimony, like
the arsenic is volatilized off the copper and oxidized, and the
white oxide condenses on the side of the tube; but the subli-
mate, from its low degree of volatility, condenses close to the
copper; moreover, it is generally non-crystalline, rarely in
acicular or octahedral crystals.
Shake out the copper and boil water in the tube for several
minutes. Do the same with the arsenical sublimate similarly
obtained. The latter slowly dissolves, and may be recognized
in the solution by means of silver ammonium nitrate; the
antimonial sublimate is insoluble.
3. Perform the operations described under Marsh's test for
arsenic (reaction 3, p. 178), placing the apparatus in a well-
ventilated fume-cupboard and carefully observing all the de-
tails there mentioned, but using a few drops of solution of anti-
monious chloride or of tartar emetic instead of the arsenical
solution,
treated, does not dissolve.
Pass a slow current of hydrogen sul
yery-tube removed from the hydrogen apparatus (p. 181),
when the air has been expelled from the tube, gently heat
192 THE METALLIC RADICALS,
that portion containing the deposit of arsenic ; the latter will he
converted into a yellow sublimate of arsenous sulphide. Re-
move the tube from the hydrogen-sulphide apparatus, and
repeat the experiment with an antimony deposit; it is con-
verted into an orange antimonious sulphide, whieh, moreover,
owing to inferior volatility, condenses nearer to the flame than
the arsenous sulphide does.
Pass dry hydrochloric acid gas through the twodelivery-tubes.
This is accomplished by adapting first one tube and then the
other, by means of a cork, to a test-tube containing a few lumps
vf common salt, upon which a little sulphuric acid is poured
prior to the insertion of the cork. The antimonious sulphide dis-
solyes and disappears; the arsenous sulphide is unaffected.
Antidote in cases of Antimonial Poisoning.—The introduc-
tion of poisonous doses of antimonial compounds into the
stomach is fortunately quickly followed by vomiting. If yomit-
ing has not occurred, or apparently to an insufficient extent,
tannic acid in any form may be administered (infusion of tea,
nut-galls, cinchona, oak bark, or other astringent solutions or
tinctures), an insoluble antimony tannate being formed, and
absorption of the poison being thereby somewhat retarded.
The stomach-pump or stomach-siphon must be applied as
quickly as possible.
Recently precipitated moist ferric hydroxide is also, accord-
ing to T. and H. Smith, a complete precipitant of antimony
from its solutions, the chemical action being probably, they
say, similar to that which takes place between ferric hydrox-
ide and arsenous anhydride. It may be given in the form of
a mixture of ferric chloride with either sodium carbonate or
other soluble carbonate or bicarbonate, or with magnesia.
These statements may be verified by mixing together the vari-
ous substances, filtering and testing the filtrate for antimony in the
usual manner.
—=_
QUESTIONS AND EXERCISES,
What is the composition and source of “Black Antimony” J—In what
alloys is metallic antimony a characteristic ingredient?—What is the
quantivalence of antimony as far as indicated by the formulm~ of the offi-
cial preparations ?—Show by an equation how ‘‘Butter of Antimony” is
prepared.—Write out equations or diagrams expressive of the renctions
which ocenr in converting antimonious chloride into oxide.—What is the
formula of Tartar Emetic?—Explain by aid of equations the preparation
of sulphurated antimony.—Give a comparative statement of the tests for
arsenic and autimony.—How is antimony detected in the presence
arsento ? |
TIN. 193
TIN : Sn, Atomic weight, 118.1.
Occurrence, ete.—The chief ore of tin is stannic oxide, SnO,,
occurring in veins under the name of ¢instone, or in alluvial depos-
its as sfream-tin. The oldest mines are those of Cornwall. Much
tin is now imported from Australia, The metal is obtained by
reducing the roasted and washed ore by means of charcoal or
anthracite’ coal at a high temperature, and is purified by slowly
heating, when the pure tin, fusing first, is run off, a somewhat less
fusible alloy of tin, with small quantities of ursenic, copper, iron,
or lead remaining. The latter is known as b/ock tin; the former
heated until brittle and then hammered or let fall from a height
splits into prismatic fragments resembling those of starch or of
columnar basalt, and is named dropped or grain tin. Good tin on
being bent emits a crackling noise, which is termed the ‘‘ery’’ of
the tin, and is caused by the friction of its crystalline particles on
each other, —
Uses. —Tin is an important constituent of such alloys as pewter,
Britannia metal, solder, speculum-metal, bell-metal, gun-metal
and bronze. It is very ductile, and may be rolled into plates, or
into leaves known as ¢in-foil, varying from ,}, to ygyq of an inch
in thickness. Common tin foil, however, usually contains a large
proportion of lead. The reflecting surface of loobing-glasses, was
formerly always an amalgam of tin and mercury, produced by
carefully sliding a plate of glass over a sheet of tin foil on which
mercury had been rubbed, and then excess of mercury had been
poured—but pure silver, deposited from a solution, is now largely
employed. Pins are made of brass or iron wire on which tin is
| i I , of which common utensils are made, is iron
red with tin by dipping acid-cleansed sheet-iron which has
been immersed in melted tallow, into vessels containing melted
tin, and subsequently heating it in a bath of melted tallow, which,
by nting oxidation, enables .the tin more completely to alloy
with the iron. Tin tacks are in reality tinned iron tacks, Tin
may be granulated by melting it and triturating it briskly ina hot
; or by shaking melted tin in a box, on the inner sides of
which chalk has been rubbed. It may also be obtained in thin
bell-shaped or corrugated fragments (Tin, U. 8. P.), by melting it in
n ladle, and, as soon as it is fluid, pouring it from the height of a
few feet into water. Powdered tin has been used medicinally as
a mechanical) irritant to promote expulsion of worms.
Tin forms two sets of compounds which are called stannous
and stannic, respectively. They correspond to the two oxides,
8n0 and Sn0,,.
© Anthracite (from av@pof, anthrax, a burning coal), or stone coal, differs
from the 3 bifuminous or caking coal in containing less volatile
matter, and therefore, in burning without flame. It gives a higher
temperature, and its non-caking properties, is, in furnace operations,
more manageable than bituminous cual.
mA
THE METALLIC RADICALS.
Stannous Chloride.
Experiment 1.—Warm a fragment of tin with hydrochloric
acid; hydrogen escapes and a solution of stannous chloride,
SnCl,, is formed. It may be retained for future experiments.
The solution obtained by dissolving tin in hot concentrated
hydrochloric acid (some undissolved tin being kept in the liquid)
and dissolving the stannous chloride crystals so obtained in 10
parts of water, constitutes the ‘‘ Stannous Chloride Test-Solution,”
Ue Fs
Solid Stannous Chloride,—By the evaporation of the above
solution, stannous chloride is obtainable in crystals, SnCl,, 2H,0.
It is a powerful reducing agent, even a dilute solution prec ipita-
ting gold, silver and mercury from their solutions, converting ferric
and cupric into ferrous and cuprous salts, and partially deoxidi-
zing arsenic, manganic, and chromic acids. It absorbs oxygen
from the air and is decomposed when added to a large quantity of
water unless some acid be present. It is used as a mordant in
dyeing and calico-printing.
Stannic Chloride.
Experiment 2.—Pass chlorine through a portion of the
solution of the stannous chloride of the preceding experiment ;
a solution of stannic chloride, SnCl,, is formed. Or add
hydrochloric acid to the stannous solution, boil, and, in a
fume-cupboard, slowly drop in nitric acid until no more fumes
are evolved; again stannic chloride results. Reserve the
solutions for subsequent experiments.
Stannic Oxide, or Anhydride, and Stannates.
Experiment 3.—Bvoil a fragment of tin with nitric acid,
evaporate to dryness, and strongly ignite the residue; light
huff-tinted stannic anhydride, SnO., is produced. Heat the
stannic anhydride with excess of solid potassium or sodium
hydroxide ; stannate of the alkali-metal (K,SnO, or NaSnO,)
results, Dissolve the stannate in water, Sol add hydrochloric
acid; white gelatinous stannic acid, H,SnO,, is precipitated.
Stannic acid is also obtained on adding a solution of a
caustic alkali to solution of stannic chloride; it is soluble in
excess of acid or of caustic alkali, The precipitate in this
case appears to correspond to the formula HSn0O,, but it
easily loses water and becomes H, SnQ,.
TIN.
SnCl, + 4KOH = H,Sn0, + 4KCl
Sn(OH), — H,O + H,Sn0,
The product of the action of nitric acid on tin is also an acid,
but it is different from ordinary stannic acid inasmuch as it is con-
verted by hydrochloric acid into metastannic chloride, which is
insoluble in moderately concentrated hydrochloric acid although
soluble in water. It is called metastannie acid, and its molecule
bably has the composition expressed by the formula H,,Sn,0,,.
{ dried over oo soe i or at 100° C,, it becomes H,8n,0,.
iesdlaan aalt, H,NaSn,0,,). This latter substance is also pro-
duced by gently bedtin’y the acid resulting from the interaction
of potassium hydroxide and stannic chloride.
5H,Sn0, = H,,8n,0,, + 5H,O
Both acids yield bufl-colored stannic oxide or anhydride, 5n0,,
when strongly heated. The latter is employed in Polishing plate
under the name of putty powder. Sodium stannate, Na SnO,,3H,0O,
is used as a mordant by dyers and calico-printers under the name
of fin prepare-liquor.
Analytical Reactions of Tin Compounds.
Stannous or Stannic Salts—Heat any solid compound of
tin with a mixture of potassium cyanide and sodium carbonate
on charcoal in the inner flame of the blowpipe. Hard glob-
ee of cn ate which, when cut by a knife, exhibit a
right white surface.
Reactions of Stannous Salts.
1. Through a dilute solution of a stannous salt (stannous
chloride, for example) pass hydrogen sulphide; a brown pre-
cipitate of stannous sulphide, Sn, results. Pour off the
supernatant liquid, add ammonia water to the moist precipi-
tate iam ite to neutralize acid dy and then ammonium hydrosulphide
solution; the precipitate is at least partially dissolved. The
addition of some sulphur and the application of heat may be
necessary to effect complete solution.
Aqueous solution of ammonium hydrosulphide becomes yellow
when a day or two old, and then contains excess of sulphur, : some
of that element having become displaced by oxygen absorbed from
the air. As a consequence of this (or by the aid of the added sul-
pees), the stannous sulphide, Sn, tukes up sulphur and dissolves
form ammonium thiostanate. From this solution yellow stan-
196 THE METALLIC RADICALS.
nie sulphide (usually mixed with sulphur) is precipitated by the
addition of excess of an acid.
2Sn8 + 4NH,HS + 8, = 2(NH,),Sn8, + 2H,8
(NH,),SnS, + 2HCl = 2NH,Cl + HS + Sn8,
2. To a solution of a stannous salt add solution of potassium
or sodium hydroxide; a white precipitate of stannous hydrox-
ide, Sn(OH),, is produced. Add excess of the alkali; the
precipitate dissolves. Boil the solution; some of the tin is
reprecipitated as blackish stannous oxide, SnO, Ammonia
water gives a similar white precipitate, insoluble in excess,
The alkali-metal carbonates do the same, carbonic anhydride
escaping.
Reactions of Stannie Salts,
1. Through a solution of a stannic salt (stannic chloride,
for example) pass hydrogen sulphide; a yellow precipitate of
stannic sulphide, SpS,, results. Pour off the supernatant
liquid, and to the moist precipitate add ammonia water (to
neutralize acid), and then ammonium hydrosulphide; the pre-
cipitate dissolves.
Note.—In this reaction the presence of much hydrochloric acid
must be avoided, and the formation of the precipitate is facilitated
if the solution be warmed. Stannic sulphide, like the arsenic and
antimony sulphides, dissolves in solutions of alkali-metal sulphides
or hydrosulphides, with formation of definite crystallizable thio-
stannates (M.Sn8,).
Anhydrous stannic sulphide, prepared by sublimation, has a
yellow or orange lustrous appearance, and is know as mosaie gold.
It was formerly used by decorators as bronzing-powder, but the
latter now usually consists of powdered bronze-leaf,
2. To a solution of a stannic salt add potassium or sodium
hydroxide; a white precipitate of stannic acid, H,SnO,, is
produced. Add excess of the alkali; the precipitation dis
solves. Boil the mixture; no reprecipitate occurs—a reac-
tion by means of which stannic may be distinguished from
stannous salts.
Ammonia water gives a similar precipitate slowly soluble in
excess. Potassium and sodium carbonates do the same, carbonic
anhydride escaping; after a time the stannic salt is again deposited,
probably as potassium or sodium stannate, Ammonium carbonate
and all the bicarbonates give a precipitate of stannic acid, insol-
uble in excess, .
GOLD, 197
Separation of Antimony and Tin,—If a piece of iron wire be
placed in the acid (HCI) solution of the two metals, a black pre-
cipitate of antimony is formed, and the tin is reduced to the stan-
nous condition; the latter may be detected by the addition of mer-
curi¢ chloride solution, when a white precipitate of mercurous
chloride is produced.
2HgCl, + SnCl, = SnCl, + 2HgCl
Antidotes.—In cases of poisoning by tin salts (e.g., dyers’ tin-
liquor), solution of ammonium carbonate should be given; and
white of egg is also said to form an insoluble precipitate. Vom-
iting should be induced, and the stomach-pump, or stomach-
siphon, applied.
GOLD: Au. Atomic weight, 195.7.
Oceurrence, etc.—Gold occurs in the free state in nature, occa-
sionally in nodules or nuggets, but in alluvial deposits commonly
in a finer state of division termed go/d dust. Gold is separated
from sand, crushed quartz, or other earthy matter with which it
be associated, by agitation with water, when the gold, from
its relatively greater specific gravity, falls to the bottom of the
vessel first, the greater part of the lighter mineral matter being
carried away by the water. From the rich sediment the gold is
dissolved out by mercury; the amalgam is filtered and afterward
distilled, when the mercury volatilizes and gold remains. —
amalgamation may be facilitated by the use of sodium,
described under silver. From even the poorest ores gold may be
dissolved by solution of rt cyanide in presence of air.
AK Ani puaaee on | ule leaf, 1857.) 8KCn + 4Au + O,4-2H,0 =
+4
is too ‘oft for use in the form of coins for general cir-
satan Gold coin is usually an alloy of copper and gold, that
of the United States, France, and Germany contains about 10 per-
_ of r; the gold coinage of Great Britain contains 1 part
wend uf 11 of gold. Australian gold coins contain silver in-
shed rele alloy. Jewellers’ gold varies in quality, every
containing 18, 15, 12, or 9 parts of gold, these alloys
he technically termed 18, 15, 12, or 9 carat fine, the reckoning
being { in the old “parts per 24,"' instead of the more usual parts
t. Articles made of the better qualities are usually stamped
authority. Trinkets of inferior intrinsic worth are often thinly
coated with pure fold by electro-deposition or otherwise. The so-
called mystery is an alloy of about 1 part of platinum and 2
Petes with a little silver. It resists the action of concen-
| nitric acid. The action of aqua regia and then ammonia
| the presence of copper in it. Gold leaf is nearly pure gold | Wy
to 4 percent, of silver or copper, according to the lighter or datkes
198 THE METALLIC RADICALS,
tint required) passed between rollers till it is about ¢4,, of an inch
in thickness and then hammered between sheets of animal mem-
brane, termed gold-beaters’ skin, and calf-skin vellum till it is
reduced to redsos OT gooeoo Of an inch in thickness, It may even
hammered till 280,000 leaves would be required to form a pile an
inch thick,
Experiment.—Place a fragment of gold (e.g. gold leaf) in
ten to twenty drops of aqua regia (a mixture of three
of nitric and four or five of bydrochloric acids), and set aside
in a warm place (in a fume-cupboard ); a solution of chlor-
auric acid, HAuCl,, (formerly regarded as a solution of gold
trichloride or auric chloride, AuCl,), results. Evaporate to
dryness, fuse, moisten with water, pour off the clear liquid,
and retain it for subsequent experiments. Such a solution is
official (Gold Chloride Test Solution, U. 5 P.), Chlorauric
acid is very deliquescent. Sodium chloraurate, NaAuCl, isa
readily crystallizable salt, A mixture of equal parts of anhy-
drous gold chloride and anhydrous sodium chloride is official
(Auri et Sodit Chloridum ).
This reaction is of analytical interest; for in examining a sub-
stance suspected to be or to contain metallic gold, solutions would
have to be effected in the above way before reagents could be
applied, as gold is insoluble in hydrochloric, nitrie, or any other
single acid,
Analytical Reactions of Gold.
1. Through a few drops of solution of a chloraurate or of
an auric salt (the chloride, AuCl,, is the only convenient aurie
salt) pass hydrogen sulphide i in the cold; a black precipitate
of aurous-auric sulphide, Au,S,, is produced, This precipitate
dissolves, with difficulty, in yellow ammonium sulphide. If
the hydrogen sulphide be passed through a boiling solution, a
brown precipitate of metallic gold is produced.
2. A solution of a chloraurate or of a gold salt add a ferrous
salt, and set aside; metallic gold is precipitated in the form of
a yellowish or reddish-brown lustrous powder, a ferric salt
remaining in solution. Ovxalie acid, also, and most free metals
similarly precipitate gold, the ‘supernatant liquid acquiring a
purplish hue,
This is a convenient way of preparing pure gold, or fine gold, as
it is te rmed, or of working up the gold residues from laboratory
operations. The precipitate, after boiling with hydrochloric aeid,
washing and drying, may be obtained as a button by mixing with
PLATINUM. 199
an equal weight of borax or potassium bisulphate and fusing in a
crucible in a good furnace,
3. Add a few drops of dilute solutions of stannous and
stannic chlorides to a considerable quantity of distilled water ;
pour the liquid, a small quantity at a time, into a very dilute
solution of aurie chloride, and stir well; the mixture assumes
a purple tint, and flocks of a precipitate, known as the Purple
of Cassius (from the name of the discoverer, M. Cassius), are
produced. The presence of more than a trace of a free acid
must be avoided.
Purple of Cassius is also formed on immersing a piece of tin
foil in a solution of auric chloride; it is said to be a mixture of
auric, aurous, stannic, and stannous oxides; but recent experi-
ments suggest that it may be merely stannic acid, mechanically
colored with metallic gold. It is the coloring agent in the finer
varieties of ruby glass,
PLATINUM : Pt. Atomic weight, 193.3,
Occurrence. —Platinum, like gold, occurs in nature in the free
state, the chief sources of supply being Mexico, Brazil and Siberia.
Alloyed with iridium, osmium, and other rare metals, it is met with
in the form of gray grains or powder in alluvial deposits, frequently
associated with gold. It is separated from the soil by washing.
Uses. —Platinum is chiefly employed in the form of foil, wire,
crucibles, spatulas, capsules, evaporating-dishes and stills, for the
purposes of the analyst and chemical manufacturer. It is toler-
ably hard, fusible with very great difficulty, and not dissolved by
hydrochloric, nitric, or sulphurie acid; but it is somewhat readily
attacked by alkaline substances, It is dissolved by aqua regia
with production of chloroplatinic acid, H,PtCl,. It forms fusible
itlloys with lead and other metals, and with phosphorous an easily
fused phosphide. None of these substances, therefore, nor mix-
tures which may yield any of them, should be heated in platinum
_ vessels, Hammered platinum vessels are the most durable. They
are best cleaned by fusing a small quantity of potassium bisulphate
in them, and dissolving out the fused salt by boiling in water.
should not be either heated or cooled very suddenly. They
should only be heated in the upper portion of the Bunsen or blow-
pipe-flame, as exposure to the lower parts of these flames, which
contain incompletely burnt gases, give rise to the formation of a
brittle carbide. Red-hot platinum vessels should not be. pe ermitted
to neta Lt contact with any metallic support, unless one made
of
Poe anecis pera gated of a at 15.5° C. is 21. Bra and th that of
the allied iridium, 22.4
200 THE METALLIC RADICALS.
Experiment.—Place a fragment of platinum in a small
quantity of aqua regia, and set the vessel aside in a warm
place (in a fume-cupboard ), adding more acid from time to
time if necessary; a solution of chloroplatinic acid, H,PtCl,
(formerly regarded as simply a solution of platinic chloride,
PtCl,), results. Evyaporate the solution to remove the excess
of acid, and complete the desiccation over a water-bath, Dis-
solve the residue in water, and retain the solution for sub-
sequent experiments and as a reagent for the precipitation of
potassium and ammonium salts, Platinum treated in this
manner, and the resulting chloroplatinic acid dissolved in
water, forms “Platinic Chloride Test Solution,” U.S, P.
Analytical Reactions of Platinum.
1. Through a few drops of a solution of a chloroplatinate,
or of a platinic salt to which an equal quantity of a solution of
sodium chloride has been added, pass hydrogen sulphide; a
dark-brown precipitate of platinic sulphide, PtS,, is produced.
Filter, wash, and add ammonium hydrosulphide ; the preeipi-
tate dissolves with some difficulty.
If sodium chloride be not present in the above reaction, the
presipitated sulphide will contain platinous chloride, and may
detonate if heated.
2. Add excess of sodium carbonate and some sugar to a
solution of a chloroplatinate or of platinie chloride, and boil;
a black precipitate of metallic is produced.
Platinum black is the name of this precipitate. Tt possesses in
a high degree a quality common to many substances, of which
platinum is a notable example—that, namely, of absorbing or
occluding gases. In its ordinary state, after well washing and
drying, it absorbs from the air, and retains, many times its own .
volume of oxygen. <A drop of ether or alcohol placed on it is
rapidly oxidized, the platinum becoming hot. This action may be
prettily shown by pouring a few drops of ether into a beaker,
loosely covering the latter with a card, through which there passes
a platinum wire, the lower end of which terminates in a short coil
or helix near the surface of the ether: on now warming the helix
in & flame and then rapidly introducing it into the beaker, it will
become red-hot and continue to glow. In this experiment partial
combustion goes on between the ether vapor and the concentrated
oxygen of the air, the products of the oxidation revealing them-
selves by the odor (chiefly that of formaldehyde),
PLATINUM. 201
3. To a solution of a chloroplatinate or of platinic chloride
add solution of ammonium chloride; a yellow crystalline
precipitate of ammonium chloroplatinate, (NH,),PtCl,, is
produced. When it is slowly formed in dilute solutions, the
precipitate is obtained in minute orange prisms. Collect the
precipitate, dry it, and heat it in a small porcelain crucible; it
is decom , and metallic platinum, in a finely divided
gray state (spongy platinum), remains.
Potassium chloride, KCI, gives a similar precipitate of potassium
chloroplatinate, K,PtC],, Heat decomposes the potassium salt
into Pt+2KCl+-2Cl,, the chlorine escaping and the potassium
chloride remaining with the platinum.
The corresponding sodium compound, Na,PtC),, is soluble in
water.
In working up the platinum residues from laboratory operations,
the mixture should be dried, burnt, boiled successively with hydro-
chloric acid, water, nitric acid, water, then dissolved in aqua
ia, excess of acid being removed by evaporation. Ammonium
chloride is then added, the precipitate washed with water, dried,
ignited, and the resulting spongy platinum retained or converted
into chloroplatinie acid. It is by such processes that the native
platinum is treated to free it from the rare metals palladium,
rhodium, osmium, ruthenium and iridium. The spongy platinum
is converted into the massive condition by hammering it when hot,
or by fusing it in the flame of the oxyhydrogen blowpipe.
Occlusion of gases by spongy platinum,—Spongy platinum has
great power of occlusion. A small piece held in a jet of hydrogen
which is escaping into the air, causes combination of the hydrogen
with the oxygen (of the air) occluded by the platinum. The heat
given out by this combination eventually raises the platinum to a
red heat and the red-hot platinum kindles the hydrogen jet.
Débereiner’s self-lighting lamp was constructed to take advantage
of this property—the apparatus being essentially a vessel in which
hydrogen was generated by the action of dilute sulphuric acid on
and so arranged that on opening the stopcock a jet of
hydrogen impinged on some spongy platinum contained in a small
QUESTIONS AND EXERCISES,
Define tinstone, stream-tin, block-tin, grain-tin, tin plate—What is the
di between stannic acid and metastannic acid }—State the applica-
tions of tin in the arts.— Mention the chief tests for stannous and stannic
the best antidote in cases of poisoning by tin solutions.—
How is gold dust separated from the earthy matter with which it is
waturally associated ?—State the average thickness of gold leaf.—What
effect is produced on gold by hydrochloric, nitrie and nitrohyd rochloric
acids respectively ?—By what reagents may metallic gold be precipitated
202 THE METALLIC RADICALS.
from solution?—How is “purple of Cassius"’ prepared ?—Whence is
platinum obtained }—Why are platinum utensils peculiarly adapted for
vse in chemical laboratories ?—How is chloroplatinic acid prepared ?—
Name the chief tests for platinum.—What is “ platinum black "?—What
is meant by occlusion of gases ?—Describe an experiment illustrating the
power of occluding gases, possessed by metallic platinum.—How is
“spingy platinum” produced ?—By what process may platinum be
recovered from residues?
DIRECTIONS FOR APPLYING THE REACTIONS DESCRIBED IN
THE FOREGOING PARAGRAPHS TO THE ANALYSIS OF
AN AQUEOUS SOLUTION OF A COMPOUND OF ONE OF THE
ELEMENTS ARSENIC AND ANTIMONY; ALSO OF TIN IN THE
FORM OF A STANNIC SALT.?
Acidulate the liquid with hydrochloric acid, and pass
hydrogen sulphide through it:—
An orange precipitate indicates antimony,
A yellow precipitate indicates arsenic or a stannic salt.
To distinguish between arsenic and stannic salt, test the
original solution with ammonia water and with potassium
hydroxide. No precipitates: arsenic indicated. For behavior
of stannic salt compare p. 196,
The results may be confirmed by the application of other
tests.
DIRECTIONS FOR APPLYIN( ; THE REACTIONS DESCRIBED IN.
THE FOREGOING PARAGRAPHS TO THE ANALYSIS OF AN
AQUEOUS SOLUTION OF COMPOUNDS OF BOTH ARSENIC
AND ANTIMONY; ALSO POSSIBLY CONTAINING TIN IN THE
FORM OF STANNIC SALT.
Acidulate a small portion of the liquid with hydrochloric
acid, and pass hydrogen sulphide through it.
Note 1.—If the hydrogen sulphide precipitate is unmistakably
orange, antimony may be put down as present, and arsenic only
further sought by the application of Fleitmann’s test to the
1 Stannie solutions are rarely met with, but these solotions are dealt
with here, and in the anulytical directions immediately following,
because in the ordinary course of systematic analysis, tin (whether
present originally as stannous or as stannic salt) is eventually precipitated
as yellow sfawnie sulphide along with arsenic and antimony sulphides,
Prior to its separation from arsenic and antimony,
W@UALITATIVE ANALYSIS, 203
original solution, or to the solution of the sulphides in aqua regia'
freed from sulphur by boiling.
Note 2,—Antimonious sulphide is far less readily soluble than
arsenous sulphide in solution of ammonium carbonate. But
this fact possesses limited analytical value, since, in the case of
mixed sulphides, much antimonious sulphide will prevent a small
quantity of arsenous sulphide from being dissolved by the ammo-
nium carbonate, while much arsenous sulphide will carry a small
quantity of antimonious sulphide into the solution. When the
proportions are, apparently, from the color of the precipitate, less
wide, solution of ammonium carbonate may sometimes be found
useful in roughly separating the one sulphide from the other.
On filtering and neutralizing the alkaline solution by adding an
acid, the yellow arsenous sulphide is reprecipitated. The orange
antimonious sulphide, and any stannic sulphide present, will
remain on the filter.
Note 3.—Solution of potassium hydrogen sulphite is said by
Wohler to be a good reagent for separating arsenous and anti-
monious sulphides, the former being soluble, the latter insoluble
in the liquid.
Note 4.—Another reagent for separating arsenous from anti-
monhious and stannic sulphides is concentrated hydrochloric acid.
As little water as possible must be present. On boiling, anti-
monious and stannic sulphides dissolve, while arsenous sulphide
remains insoluble, The liquid, slightly diluted, filtered, mixed
with more water, and again treated with hydrogen sulphide, gives
orange antimonious sulphide, mixed with stannic sulphide when
tin is present. The presence of arsenic may be confirmed by the
application of Fleitmann’s test to the original solution.
The two processes now to be described for the detection of
arsenic and antimony are rather long, and require much care in
their performance; but they are useful, because a small quantity
of antimony in presence of much arsenic, or vice versa, may be
detected by their means. The method for detecting tin will be
ileseribed later (p. 205.) : |
Detection of Arsenic and Antimony.
Pirst process.—Generate hydrogen, as for Marsh's test
(p. 179) and pass it through a small wash-bottle containing
solution of lead acetate, to free from any trace of hydrogen
sulphide, and then through a dilute solution of silver nitrate
contained in a test-tube. When the hydrogen apparatus is
in good working order, pour into the generating bottle a
* Aqua Regia is a mixture of hydrochloric and nitric acid, Aecidum
Nitrohydrochloricum, U.S.P. It was so-called from its property of dis-
ae z oe $ ~~ pr pe — = “_--s
solving gold, the “king” of metals. ’ 2
THE METALLIC RADICALS,
quantity of the original solution to be examined, adding it
gradually to prevent violent action. After the gas has been
passing for five or ten minutes, examine the contents of the
test-tube ; arsenic, if present, will be found in the solution in
the state of arsenous acid,—
AsH, + 3H,O + 6AgNO, = H,AsO, + 6HNO, + 6Ag;
while antimony, if present, will be found in the black pre-
cipitate that has fallen, according to the following equation:
SbH, -+- 3AgNO, — SbAg, + 3HNO,
The arsenous radical may be detected in the clear, filtered,
supernatant liquid, which still contains much silver nitrate,
by cautiously neutralizing with very dilute ammonia water
or by adding a few drops of solution of silyer ammonium
nitrate, yellow silver arsenite being produced. The antimony
may be detected by washing the black precipitate, boiling it
in an open dish with solution of tartaric acid, adding hydro-
chloric acid, filtering and passing hydrogen sulphide through
the solution, orange antimonious sulphide being precipitated.
( Hofmann. )
Second process.—Obtain the metallic deposit in the middle
of the delivery-tube as already described under Marsh’s test.
Act on the deposit with hydrogen sulphide gas, and then with
hydrochloric acid gas, as detailed in reaction 3 of antimony
(p. 191). If both arsenic and antimony are present, the deposit,
after the action of hydrogen sulphide, will be found to be of
two colors, the yellow arsenous sulphide being usually farther
removed from the heated portion of the tube than the orange
antimonious sulphide. Moreover, subsequent action of hydro-
chloric acid gas causes the disappearance of the antimonjous
sulphide, which is converted into chloride and carried off in
the stream of gas,
The chief objection to this process is the liability of the operator
mistaking sulphur, deposited from the hydrogen sulphide by the
uction of heat, for arsenous sulphide. But the presence or absence
of arsenic is easily confirmed by applying Fleitmann’s test to the
Original solution, while the process is most useful for the detection
of a small quantity of antimony in the presence of much arsenic.
On the whole, Hofinann’s method is to be preferred.
COPPER. 205
Detection of Tin.
During the generation of hydrogen arsenide and antimonide in
Marsh’s apparatus, any stannic chloride present in the original
solution under examination is gradually reduced, with deposition
of metallic tin. After the testing for arsenic ‘and antimony is
concluded, pour out the contents of the generating bottle into a
dish; take out the fragments of zinc, first detaching from them
any black “2 gee or spongy deposit; separate the liquid by
filtration wash the residue (which contains any reduced tin
together with impurities derived from the zinc). Boil the residue
with a small quantity of dilute hydrochloric acid; filter, if
necessary, and test the filterate for stannous salt by adding mer-
curic chloride. A white precipitate of mercurous chloride indi-
cates the presence of tin. (Compare p, 221.)
The student may now proceed to the analysis of aqueous solu-
tions of salts of any of the métallic elements hitherto considered.
The method followed may be that for the separation of the pre-
vious three groups, hydrogen sulphide being first passed through
the solution to precipitate arsenic and antimony (also tin, if stannic
salt be present). The liquid, after the removal by filtration, of
any hydrogen sulphide precipitate and ebullition to expel
sycinten sulphide, is examined by means of the other group-
reagents for metals of the iron, zinc, barium, and magnesium
groups and then for alkali metals. (Compare pp. 106, 128, 145,
170, seal Three or four solutions at least should be examined
before proceeding to the next group of metals—copper, mercury,
ete.
COPPER: Cu. Atomic weight, 63,1,
Occurrence, etc.—The commonest ore of this metal is copper
, & copper and iron sulphide, CuFeS,, occurring in Cornwall;
Australia an Russia supply malachite, a hydroxy carbonate; much
ore is also imported from Spain and from South America, It
is smelted in enormous quantities at Swansea, South Wales, a
locality peculiarly fitted for the operation on account of its prox-
imity to the coal-field, and its position as a seaport. By Hollway’s
wepmomnical method of smelting copper pyrities and other sul-
after the sulphide is once melted, air is driven, not over,
but through the mass; the combustion of the sulphur
es self-supporting, and is greatly accelerate od.
sts termed this metal Venus, perhaps on account of
of its lustre, and gave it her symbol ¥, a compound
also indicating a mixture of goldo, and a certain
cal substance called acrimony >f, the corrosive nature
symbolized by the points of a Multese cross. To
y the blue show-bottle in the shop-window of the pharmac ist
206 THE METALLIC RADICALS.
is occasionally ornamented by such a symbol, indicating, possibly,
that the blue liquid in the veasel is a preparation of copper.
Copper forms two sets of salts, which are distinguished as cupric
and cuprous salts, and may be regarded as related { to the oxides,
CuO and Cu,O, respectively. Cupric oxide, or black copper
oxide, CuO, may be prepared by heating fragments of copper to
low redness on a piece of earthenware in an open fire, Cuprous
iodide, Cul, will be subsequently referred to as a convenient form
in which to remove iodine from solution, while the formation of
cuprous oxide, Cu,O, under given circumstances, will come under
notice as an indicator of the presence of sugar in a liquid.
Cuprie Sulphate, CaSO5H,O (Cupri Sulphas, U.S, P.), blue
vitriol, blue stone, or copper sulphate is the only copper compound
much used in pharmacy. It is a by-product in silver-refining
(Ag,80,-+Cu=Cu0,+2Ag). Some is formed in roasting copper
pyrites. In the latter case, some iron sulphide and copper sul-
phide are oxidized to sulphates; but the low red heat finally
employed decomposes the ferrous sulphate; while the cupric sul-
phate is unaffected; the latter is purified by crystallization from a
hot aqueous solution, though frequently much ferrous sulphate
remains in the crystals, Cupric sulphate is also prepared by
dissolving in dilute sulphuric acid the black oxide, CuO, obtained
in annealing copper plates (CuO+ H)SO,=CuSO,+ H,0); it may
also be obtained by boiling copper with three times its weight of
sulphuric acid (2H,SO,+Cu = CuSO,+S0,+ 2H,0), diluting,
filtering, evaporating, and crystallizing, In this proceas some
black cuprous sulphide also is formed.
Anhydrous Cuprie Sulphate, CuS0O,, is a yellowish-white powder
prepared by depriving the ordinary blue crystals of cupric sul-
phate of their water of crystallization by exposing them to a tem-
perature of about 400° F, (204° C.J. It is used in testing alcohol
and similar spirituous liquids for water, becoming blue if the
latter be present.
Experiment.— Cupric Nitrale——Digest copper in dilute
nitric acid. When action has ceased, evaporate and crystal-
lize. If the crystals form at a temperature of 73° to 80° FP.
(22.7 to 26.6° C.), they are prismatic, Cu( NO,),, 3H,O; at
lower temperatures, tabular, Cu( NO,),,6H,O.
3Cu + 8HNO, = 3Cu(NO,), + 2NO + 4H0
Copper Nitric acid Cuprie acid Nitric oxide Water
Verdigria (from verdi-gris, Sp., creen-gray) is Copper Oxy-
acetate Cu,O (C,H,0, ),, obtained by exposing alternate layers
of copper and fermenting refuse grape-husks to the action of air,
The modes of forming ¢ ‘upric Sulphid, Hydroxide, Ovide,
Ferrocyanide, and Arsenite, as well as Metallie Copper, are
incidentally alluded to in the following analytical paragraphs,
=—
COPPER.
Analytical Reactions of Cuprie Salts.
1. Pass hydrogen sulphide through an acidulated solution
of a cupric salt; a black precipitate of cupric sulphide, Cus,
is produced, which is insoluble in dilute acids.
2. To an aqueous solution of a cupric salt add ammonium
hydrosulphide; by this reagent, also, cupric sulphide is pre-
cipitated, insoluble in excess.
Note. —Cupric sulphide is not altogether insoluble in ammonium
hydrosulphide if free ammonia or much ammonium salt be present ;
it is insoluble in potassium and sodium hydrosulphides,
4. Immerse a piece of iron or steel, such as the point of a
penknife or a piece of iron wire, in a few drops of a solution
of a cupric salt; copper is deposited on the iron, with its
characteristic color, an equivalent quantity of iron passing into
solution. Ifa sufficient quantity of iron is employed and the
experiment is allowed to continue long enough, the copper is
entirely precipitated —
CuSO, + Fe = FeSO, + Cu
By this reaction copper may be recovered on the large scale
from waste solutions, old hoop or other scrap iron being thrown
into the liquors.
4. Add ammonia water to a solution of cupric sulphate ;
cupric hydroxide, Cu(OH),, of a light-blue color, is precipi-
tated. Add excess of ammonia ; the precipitate is redissolved,
forming a blue solution of cupric ammonium salt, so deep in
color as to render ammonia an exceedingly delicate reagent
for copper. From this ammoniacal solution alcohol precipi-
tates » dark-blue crystalline mass (CuSO,, 4NH,, H,O) which,
on heating to 150° C., loses water and two molecules of ammo-
nia, becoming CuSO, 2NH,, and at 200° C., it loses another
molecule of ammonia, becoming CuSO,, NH,. Other soluble
cupric salts yield similar compounds.
A cupric ammonium sulphate may be obtained in large crystals
by adding stronger ammonia water to powdered cupric sulphate
until the salt is dissolved, placing the liquid in a test-glass or
eylinder, cautiously pouring in twice its volume of nearly anhydrous
alcobol or methylated spirit, taking care that the liquids do not
become mixed, tying a piece of bladder over the mouth of the
vessel, and setting aside for some weeks in a cool place, | (Witt-
stein). - »
208 THE METALLIC RADICALS.
5. Add a solution of potassium or sodium hydroxide to a
cupric solution ; cupric hydroxide, Cu(OH),, is precipitated,
insoluble in excess. Boil the mixture in the test-tube with
excess of potassium or sodium hydroxide ; the cupric hydrox-
ide is decomposed, losing the elements of water, and becoming
converted into black anhydrous cupric oxide, CuO.
6. Add solution of potassium ferrocyanide, K,FeCy,, to an
aqueous cupric solution ; a reddish-brown precipitate of cupric
ferrocyanide, Cu,FeCy,, is produced. This is an extremely
delicate test for copper.
7. Add solution of potassium iodide to an aqueous cupric
solution ; in moderately concentrated solutions of a precipitate
of cuprous iodide, Cul, is produced, with simultaneous libera-
tion of iodine which imparts a yellow or brown color to the
solution.
2CuSO, + 4KI = 2K,80, + 2Cul + L
On adding to the mixture a solution of sulphurous acid (or of
ferrous sulphate), the color due to the free iodine is removed,
and the nearly white cuprous iodide can be recognized. Even
in very dilute euprie solutions a yellow coloration is produced
on the addition of potassium iodide, which becomes violet on
the addition of starch paste (see Iodides). This test is even
more delicate than the ferrocyanide test, but care must be taken
to ascertain that the solution of potassium iodide employed
does not contain free iodine. }
&. To a cupric solution add solution of arsenous acid,
and cautiously neutralize with alkali ; green cupric arsenite,
CuHAs0O,, is produced,
Most copper salts impart a green color to the Bunsen flame.
Cuprie chloride imparts a bluish color.
Antidotes.—In cases of poisoning by compounds of copper,
iron filings should be administered, the action of whieh 18
explained in reaction 3, Potassium ferrocyanide may also be
given (see reaction 6). Albumin forms with copper salts a
compound insoluble in water, hence raw eggs may be adminis-
tered, vomiting being induced or the stomach-pump, or
stomach-siphon, applied as speedily as possible.
MERCURY. 209
QUESTIONS AND EXERCISES.
ae a sources of copper.—Give equations showing how Cupric Sul-
on the small und large scale.—Calculate how much
Cesta Cupric Sulphate may be obtained from 100 pore of cupric
Ans, 261.05 parts.—How may Cupric Oxide repared ?—
Wie down the formula of Verdigris.What i is the analytical position of
= *—Mention the chief tests for ur Ley -—How may copper be sepa-
from arsenic ?—Whzy is finely divided iron an antidote in poisoning
by copper ?
MERCURY: Hg. Atomic weight, 198.5.
Oceurrence.—Mercury occurs in nature as sulphide, HgsS, form-
ing the ore cinnabar (an Indian name expressive of something red),
and is obtained from Spain, California, Eastern Hungary, China,
sy and Peru,
Preparation.—The metal is separated by roasting off the sulphur
and then distilling ; or better, by distilling with lime, which com-
bines with and retains the sulphur,
Properties, —Mercury (Hydrargyrum, U.S. P.), is a silver-white
lustrous metal, liquid at ordinary temperatures. It boils at 675°F.
(357° C.), and at —39° F, (—40° C.) solidifies to a malleable mass
of octahedral crystals. Its specific gravity is 13.535. When quite
free from other metals, it does not tarnish, and its globules roll
freely over a sheet of white paper without leaving any streak,
Formula.—The formula of the mercury molecule is Hg and not
nee because (at all events at the high temperature at which alone
maser. ‘on its yapor can be determined) the quantity of mercury
ich occupies the same space as that occupied by 2 grammes
of. od agers under the same conditions is 198.3 grammes, and not
tity (see p. 58). Analogous facts have been
seenies ryt ee reference to the vapors of zinc and cadmium. Mer-
aed mer iron, copper, etc., forms two sets of salts. These are
merenurous and mercuric salta, and correspond to the oxides,
and HgQ, respectively.
c+ oa —The mixture or compound formed on fusing metals
together is usually termed an al/oy (ad and ‘igo, I bind); if mereury
is a constituent, an amalgam (nddacypa, malagma, from pardcow,
malaaso, 1 soften, the presence of mercury lowering the melting-
point of such a mixture). Most metals form amalgams. Electric
amalgam, the exciting material which is rubbed against the glass
plate of an electrical machine, commonly consists of 1 part each of
tin and zine with 3 parts of mercury. Sodium amalgam has already
been mentioned (page 94).
Medicinal ndxs,—The comporfnds of mercury used in
medicine are all obtained from the metal. The metal itse Af, rub
bed with chalk, or with confection of roses and powdered liquorice- .
iu
210 THE METALLIC RADICALS.
root, or with lard and suet, until globules are not visible to the
unaided eye, is often used in medicine. The preparations are :—
Hydrargyrum cum Creta, U.S. P., or Gray Powder; Massa Hydrar-
qyri, U. 8. P. ; Unguentum Hydrargyri, U.S. P., Mercurial Oint-
ment, and Unguentum Hydrargyri Dilutum, U. 8. P., Blue Oint-
ment. There is also an official Mercurial Plaster ( &mplastrum
Hydrarqyri). Their therapeutic effects are probably due, not to
the large quantity of metallic mercury in them, but to smal! quan-
tities of black and red oxide which occur in them through the
action of the oxygen of the air on the finely divided metal. The
proportion of oxide or oxides varies according to the age of the
specimen. All these medicinal preparations of metallic mercury
are indefinite and unsatisfactory, and that through no fault of the
pharmacist. They much need investigation by pharmacists and
therapeutists.
Mercurous and Mercuric Iodides,
Experiment 1.—Rub together small quantities of mercury
and iodine, controlling the rapidity of combination by adding,
at the outset and at intervals during the operation, a few drops
of aleohol, which by evaporation absorbs heat, and thus keeps
down the temperature. The product is either mercuric iodide,
mercurous iodide, or a mixture of the two, together with mer-
cury or iodine, if excess of either has been employed. If the
two elements have been weighed out in atomic proportions,
198.3 of mercury to 125.9 of iodine (about 8 to 5), a green
or grayish-green powder results from their union, which consists
chiefly of mercurous iodide, HgI; if in the proportions of the
atomie weight of mercury to twice that of iodine (198.3 to
twice 125.9, or about 4 to 5), red mereuric iodide, Hg, results
—an iodide that is official, but made in another way (see p.
211). Mercurous iodide should be made and dried without
heating, and with as little exposure to light as possible. Mer-
curic iodide may be removed from it by well washing with
alcohol. Mercurous iodide ( Hydrargyri lodidum Flavum,
U. 8. P.), ean also be obtained as a bright yellow precipitate
by adding a solution of potassium iodide to a solution of mer-
curous nitrate, ‘care being taken that excess of the former is
avoided. (See reaction 2, p. 220).
Mercurous iodide is decomposed slowly by exposure to light,
and quickly by the action of heat, into mercuric iodide and mer-
cury. Mereurie iodide, occurring as an impurity in mereurous
iodide may be detected by digesting in ether (in which mereurous
iodide is insoluble), filtering, and evaporating to dryness; mer-
MERCURY. 211
euric iodide remains. Mercuric iodide is stable, and may be
sublimed in scarlet without decomposition. (For the
mechanical details of the method by which a specimen of the
erystals may be obtained, and the precautions to be observed, see
corrosive sublimate, p. 213).
ofr and Yellow Varieties of Mercurie Iodide-—In condensing,
mercuric iodide is at first yellow, afterward acquiring its character-
istic searlet color, This may be shown by smearing or rubbing
a sheet of white paper with the red iodide, and then holding the
sheet before a fire or over a flame for a few seconds. As soon as
the paper becomes sufficiently hot the red iodide changes to
yellow, and the salt does not quickly regain its red color when
the paper is carefully handled. But if the salt be~pressed
or rubbed in any way, the portions touched immediately return to
the scarlet condition. These color changes are accompanied by
changes in crystalline form. The red modification, stable at
ordinary temperatures, forms tetragonal crystals; the yellow modi-
fication, rhombic crystals,
2.—Preparation of Red or Mercurie Iodide by
Precipitation.— To a few drops of a solution of a mercuric salt
(corrosive sublimate, for example) add solution of potassium
iodide, drop by drop; a precipitate of mercuric iodide forms,
and at first redissolves in the excess of the mercuric salt, but
is permanent when sufficient iodide has been added. Continue
the addition of potassium iodide ; the precipitate is redissolved,
with formation of potassium mercuric iodide, KHgl..
SKE = gk + 2KCl
Mercurie ride Potassium iodide Sceouste iodide Potassium chloride
Hel, K KHgl,
Mere iodide 1 ee iodide Potassium mercuric lodide
Notes. —When first precipitated, mercuric iodide is yellowish-
red, but soon changes to scarlet. Its solubility either in solution
of the mercuric salt or in solution of potassium iodide renders the
detection of a small quantity of a mercuric salt by means of potas-
sium iodide, ora small quantity of an iodide by means of a mercuric
solution, difficult, and hence lessens the value of the reaction as a
test, But the reaction is important as the official method for the
of mercuric iodide (AHydrargyri Todidum Rubrum,
P.). Mercuric iodide made in this way has the same com-
ponition as tha that pared by direct combination of its elements.
sane ome paration, the two salts must be used in the pro- re
portion (268. 86) to 2Ki (= 829.52), The mercury in
mercuric or mercurous iodide is set free, and sublimes in. globules s,
on heating either powder with dried sodium carbon: ate in a test-
THE METALLIC RADICALS.
tube; the iodine may be detected by digesting with sodium
hy droxide solution, filtering, and to the solution of sodium iodide
thus formed adding starch-paste, acidulating with dilute hydro-
chloric or sulphuric acid, and adding a solution of a nitrite, when
blue starch iodide results, Mercuric iodide is insoluble in water,
slightly soluble in alcohol, tolerably soluble in ether.
Mercurous and Mercuric Nitrates.
Experiment 3.—Place a globule of mercury, about half
the size of a pea, in a test-tube ; add twenty or thirty drops of
nitric acid; boil slowly until red fumes no longer form ; set
aside. ° On cooling, if a globule of mercury still remains in
the tube, crystals of mercurous nitrate separate, These may
be dissolved in water slightly acidulated with mitrie acid.
The solution may be retained for subsequent analytical
operations,
3Hg + 4HNO, = 3HgNO, + 2H,O + NO
Experiment 4.—Place mercury in excess of concentrated
nitric acid, and warm the mixture; mercuric nitrate is formed,
and will be deposited in crystals as the solution cools, Or,
to crystals of mercurous nitrate add nitric acid, and boil until
red fumes are no longer evolved. Retain the product for a
subsequent experiment.
3Hg + 8HNO, = 3Hg(NO,), + 2NO + 4H,0
Mercury Nitric aci Mercuric nitrate Nitric oxide Water
When mercury and nitric acid are boiled together, mercurous
nitrate is formed if the mereury be in excess, while mercuric
nitrate is produced if the acid be in excess.
Mereurie Oxynitrates,—From the normal mercuric nitrate
several oxynitrates may be obtained. Thus on merely evapora-
ting a solution of mercuric nitrate, and cooling, crystals having the
formula Hyg,O(NO,),,2H.O are deposited. The latter, by wash-
ing with cold water, yield a yellow pulverulent oxynitrate,
Hg.O.(NO,),: mixed with lard, this has sometimes been used as
an ointme nt. By prolonged treatment with water, the yellow
oxynitrite eve tually yields mercuric oxide,
The official preparations of mercuric nitrate are Liquor Hydrar-
qyri Nitratis and Ungquentum Hydrarqyri Nitratis.
Mercurous and Mercuric Sulphates.
Experiment 5.— Boil two or three grains of mereury with a
few drops of concentrated sulphuric acid in a test-tube or
amon! | dish, iN) ny fume-c upboard ; sulphurous anhydride is
MERCURY. 213
evolved, and mercuric sulphate, HgSO, a white, heavy,
crystalline powder results.
Hg + 2HSO, = HgSO, + 80, + 2H0
Mercury Sul uric Mercuric Sulphurous Water
wcid sulphate anhydride
Between two and three ounces of mercuric sulphate may
be prepared from a fluid drachm of mercury and a fluid
ounce of sulphuric acid boiled together in a small dish. The
operation is completed and any excess of acid removed by
cautiously evaporating the mixture of metal and liquid to
dryness, in a fume-cupboard (sulphuric acid vapors being
excessively irritating to the mucuous membrane of the nose
and throat); dry crystalline mercuric sulphate remains. If
residual particles of mercury are observed, the mass should
be moistened with sulphuric acid and again carefully heated.
By-products.—In chemical manufactories, secondary products,
such as the sulphurous anhydride of the above reaction, are
termed by-products, and, if of value, are utilized, In the present
case the gas is of no immediate use, and is therefore allowed to
escape. When very pure sulphurous anhydride is required for
experiments on the smal! scale, this would be the best method of
making it, a delivery-tube being adapted by means of a cork to
the mouth of a flask containing the acid and metal.
Mercurie Oxysulphate.—Water decomposes mercuric sulphate
into a soluble acid salt and an insoluble yellow oxysulphate,
: » The latter is called Turpeth mineral, from its resem-
hlance in color to vegetable turpeth, the powdered root of Jpomea
furpethum, an Indian substitute for jalap.
Experiment 6.—Rub a portion of the dry mercuric sulphate
of the preceding experiment with as much mercury as it
already contains; the product, when the two have completely
combined, is mercurous sulphate, Hg,SO,: it may be retained
for a subsequent experiment. The exact proportion of
mercury to mercuric sulphate is merely a matter of calcula-
tion based upon the equation representing the chemical change
whieh takes place.
HgSoO, +- Hg = Hg,80,
Mercurous and Mercuric Chlorides.
Experiment 7.—Mix thoroughly a few grains of dry mer-
eurie sulphate with about four-fifths of its weight of sodium
ehloride, and heat the mixture, slowly, in a test-tube in a
THE METALLIC RADICALS,
fume-cupboard ; mercuric chloride, HgCl,, or corrosive subli-
mate, bichloride or perchloride of mereury (Hydrargyri
Chloridum Corrosivum, U.S. P.), sublimes and conthcsien ta in
the upper part of the tube in heavy colorless crystals.
Somewhat larger quantities (in the proportion of 20 of
mercuric sulphate to 16 of sodium chloride and, vide tnfra, 1
of black magnese oxide) may be sublimed in a pair of two-
ounce or three-ounce round-bottomed gallipots, the one
inverted over the other, and the joint luted by means of
moist fireclay (the powdered clay kneaded with water to the
consistence of dough). The luting
having been allowed to dry (some-
what slowly to avoid cracks), the
pots are placed upright on a sand-
bath, sand piled round the lower
and a portion of the upper pot,
and the whole heated over the
flame of a good Bunsen burner for
an hour or more in a fume-cupboard
(see Fig. 36—in which the pots are
represented as raised in order to
show the joint). Mercurie iodide,
and calomel, may be sublimed in
the same way. The temperature
required for the former is some-
what lower than that for corrosive sublimate while that for
the latter is higher.
HgSO, + 2NaCl — HgCl, + Naso,
Mercuric Sodium Mercuric 80 ium
sulphate chloride chloride sulphate
Sublimation,
Note.—If the mercuric sulphate contains any mercurous sul-
phi ite, some calomel may be formed. This result will be avoided
if 2 or 3 percent. of black manganese oxide be previously mixed
with the ingrec ‘dients. The action of this oxide is to turn out from
the excess of sodium chloride used in the process the chlorine
necessary to convert any ‘calomel into corrosive sublimate, sodium
manganate and | ut lower manganese oxide being simultaneously
produc ed,
Precaution —The Ope ration must be condueted with care in a
fume-cupboard, because the vapor of corrosive sublimate, which
might possibly escape, is very acrid and highly poisonous, Mereuric
chloride volatilizes, though extremely slowly and slightly, at the
ordinary temperature of warm weather,
Unless preserved in an amber-colored bottle, a yery dilute
MERCURY. 215
uqueous solution of mercuric chloride, when long kept, is liable to
decomposition, calomel being precipitated, water decomposed,
hydro@hloric acid formed, and oxygen evolved.
Experiment 8.—Mix « few grains of the mercurous sulphate
from experiment 6 with about a third of its weight of sodium
chloride, and sublime in a test-tube; crystalline mercurous
chloride, HgCl, or calomel (Hydrargyri Chloridum Mite,
U.S. P.) results. Larger quantities may be prepared in the
manner directed for corrosive sublimate, a somewhat higher
temperature being employed : similar precautions must also be
observed.
HgSO, + 2NaCl = 2HeCl + N
Sodium Mercurous Tee
sulphate chloride chloride sulphate
Calomel may also 3 made by other methods. The name calomel
(xadéc, kalos, good, and jéAac, melas, black) was probably indica-
tive of the esteem in which black mercuric sulphide (the compound
to which the name calomel was first applied) was held.
Test for corrosive sublimate in calomel,—If the mercurous sul-
phate employed in this experiment contain mercuric sulphate,
some mercuric chloride will also be formed. Corrosive sublimate
is soluble in water, calomel insoluble ; the presence of the former
may therefore be proved by boiling a few grains of the calomel in
distilled water, filtering and testing by means of hydrogen sulphide
or ammonium hydrosulphide as described hereafter, Or two or
three grains of the suspected calomel may be mixed with a drop
of 10 percent. alcoholic soap solution and a drop of freshly pre-
wed alcoholic solution of guaiacum resin, and the mixture well
stirred with 2 Oc. of ether. On evaporating the ethereal solution,
the presence of mercuric chloride is indicated by an intense green
coloration. If corrosive sublimate be present, the whole bulk of
the calomel must be washed with hot distilled water till the filtrate
ceases to give any indications of the impurity. Corrosive subli-
mate is more soluble in alcohol, and still more in ether, than it is
in water, while calomel is insoluble in all three. Ether in which
calomel ‘bas been digested should therefore, after filtration, yield
no residue on evaporation. Calomel is converted by hydroey vanic
acid into mercuric cyanide and a black powder readily yie ding
metallic mercury. Powell and Bayne have shown that a certain
oy of hydrochloric acid arrests this action,
—Carefully purified cotton, bleached by dilute ' ble aching
solution and thoroughly washed, takes up mere cury from
lute ayotons of mercuric chloride, thease Tie See
ware fis mercuric aixide. Senne,
should not be filtered through cotton w ro
216 THE METALLIC RADICALS.
Mercuric Oxide.
Experiment 9.—Evaporate to dryness, in a small dish in a
fume-cupboard, the mercuric nitrate from experiment 3 and
heat the residue till no more nitrous fumes are evolved ; red
mercuric oxide, HgO, red precipitate (Hydrargyri Oxidum
Rubrum, U.S. P.) remains.
2Hg(NO,), = 2HgO + 4NO, + VD,
Mercurie nitrate Mercuric oxide Nitrogen peroxide Oxygen
A much larger yield of mercuric oxide (for the same quantity
of nitric acid used to dissolve mercury) may be obtained by heating
mercurous nitrate, or by thoroughly mixing with the dry mercuric
nitrate from experiment 4 (prior to heating it) as much mercury as
it already contains (ascertained by calculation from the atomic
weights and the weight of mercuric nitrate employed, as in making
mercurous sulphate). In this case the free mercury is also con-
verted into mercuric oxide,
Hg(NO,), + Hg = 2HgO + =32NO; .
Mercuric nitrate Mercury Mercuric oxide Nitrogen peroxide
Mercuric oxide is tested for nitrate by heating a little of the
sumple in a test-tube, when orange nitrous vapors are produced
and are visible in the upper part of the tube, if nitrate be present,
Mercurie oxide is an orange-red or red powder, more or less erys-
talline according to the extent to which it may have been stirred
during preparation from the nitrate. Unguentum Hydrargyri
Ovxidi Rubi, is official. Mercuric oxide, in contact with oxidizable
organic matter, is liable to reduction to black or mercurous Oxide,
The earliest mode of preparing mercuric oxide consisted in main-
taining mercury at a temperature near its boiling-point for many
days in vessels, nearly closed to the air, in which a large surface
of the metal was exposed, A red powder, which was called preeipi-
fatum per se, was gradually formed. It was from mercuric oxide
a0 prepared that Priestly first obtained oxygen.
Experiment 10.—To solution of potassium or sodium hydrox-
ide, or to lime-water, in a test-tube or a larger vessel, add solu-
tion of corrosive sublimate, mercuric nitrate, or almost any
other mercuric salt (but not mercuric cyanide); yellow mer-
euric oxide, HgO ( Hydrargyri Oridum Flavum, U. 8. P.) is
precipitated.
HgCl, + Ca(OH), = HgO + CaCl, + HO
Mercuric Calcium Mercuric Calcium Water
chloride hydroxide oride chloride ‘
The precipitate only differs physically from red mereurie oxide ;
the yellow oxide is more minutely divided than red, Unguentum
HTydrarqyri Oxidi Flavi, is official.
MERCURY.
Mercurous Oxide.
Experiment 11.—To calomel add solution of potassium or
sodium hydroxide, or lime-water; black mercurous oxide,
Hg,O, is produced, and may be filtered off, washed and dried.
2HgCl + Ca(OH), = Hg,O + CaCl, +
Merenrous Caleium Mercurous Calcium gn
ebloride hydroxide oxide chloride
This reaction and the formation of a white curdy precipi-
tate on the addition of solution of silver nitrate to the filtrate
from the mercurous oxide, acidulated by nitric acid, form
sufficient evidence that a powder consists of or contains calo-
mel. ‘The curdy precipitate is silver chloride.
Analytical Reactions of Mercury Compounds.
The Copper Test (for-Mercurous or Mercuric Salts ).—Place
a small piece of a bright copper, about half an inch long and
a quarter of an inch broad, in a solution of any salt of mer-
cury, mereurous or mercuric, and heat in a test-tube, the cop-
becomes coated with mercury, in a fine state of division.
(The absence of any notable quantity of nitric acid, must he
ensured, or the whole of the copper will be dissolved. Pour
away the supernatant liquid from the copper, wash the latter
in the tube once or twice with water, remove the metal, dry it
by gentle pressure in a piece of filter-paper, place it in a dry,
narrow test-tube, and heat it to redness in a Bunsen flame, the
tube being held in an almost horizontal position ; the mercury
yolatilizesand condenses as a whitish sublimate of minute glob-
ules on the cool part of the tube. The globules aggregate on
being gently pressed with a glass rod, and are especially visible
where flattened between the rod and the side of the test-tube.
Notes on the test.—This is a valuble test for several reasons:—
It is very delicate when performed with care. It seperates from
the substance under examination, mercury itself, an element which,
from ite = ine lustre and fluidity, cannot be mistaken for any
other, plicable to both mercurous and mercuric salts.
Tt renders “Bade <p the detection of mercury in the presence of most
other substances, organic or inorganic.
In g the test, the presence of any considerable quantity
of nitric acid may be ay oided by adding an alkali until a sli ight per-
manent ipitate appears, and then very slightly rei vcidifying
with a drop or two of acetic acid ; or by conc centrating in an
hes or ting-dish after adding a little sulphuric acid and then
218 THE METALLIC RADICALS,
Analytical Reactions of Mercurie Salts.
1. To a few drops of a solution of a mercuric salt (corrosive
sublimate, for example) add solution of potassium iodide, drop
by drop; a yellowish-red precipitate of mercuric iodide, Hg
forms, and at first redissolves, but is permanent when suffi-
cient potassium iodide has been added. Continue the addition
of potassium iodide; the precipitate is redissolved. (See
notea on p. 211.)
Ammoniated Mercury.
2. Add a solution of a mercuric salt to ammonia water,
taking care that the mixture, after well stirring, still smells
of ammonia; a white precipitate is produced.
Performed in a test-tube, this reaction is a very delicate test for
the presence of a mercuric salt; performed in larger vessels, the
mercuric salt being corrosive sublimate; it is the process for the
preparation of white precipitate, formerly called ammonio-choride
of mercury, now known as Ammoniated Mercury (/fydrargyrum
Ammoniatum, U.S. P.).
HgCl, + 2NH, = NH,HgCl + NHC
Mercuric Ammonia White Ammonium
chloride precipitate chloride
This precipitate is considered to be mercuri-ammonium chloride,
NH,HegCl,—that is, ammonium chloride, NH,Cl, in which two
atoms of hydrogen are replaced by one atom of mercury, When
warmed with potassium hydroxide it evolves ammonia,
Varieties of Ammoniated Mereury.—If the order of mixing the
solutions in reaction 2 be reversed, and ammonia be added to solu-
tion of mercuric chloride, a double mercuri-ammonium and mer-
curie chloride, NH,HgCl,HgCl,, is produced: it contains 76.57
percent, of mercury, A double mereuri-ammonium and ammo-
nium chloride, NH,HgCl,NH,Cl, containing 65.57 percent. of
mercury made by adding caustic potash or caustic soda to a solu-
tion of equal parts of corrosive sublimate, and sal-ammoniac, is
known as ‘‘fusible white precipitate,’’ because at a temperature
somewhat below redness it fuses and then volatilizes, The official
white precipitate contains theoretically, 79.52 percent. of mereury.
An ointment prepared with this compound is official (Uaguentum
Hydrargyri Ammoniati, U.S. P.). Prolonged washing with water
converts white precipitate into a yellowish compound (NH HgCl,
HgO); hence the official preparation is not thoroughly freed from
the ammonium chloride which is formed during its manufacture,
but which, if present in larger proportion than 7 or 8 percent.,
gives to it the character of partial or complete fusibility, The
MERCURY. 219
officially recognized ammoniated mercury should volatilize at a
temperature below redness without fusing, and should yield 78 to
79 percent. of metallic mercury. With iodine, chlorine, or
bromine, white precipitate may yield the dangerously explosive
nitrogen iodide, chloride, or bromide.
Dimercuri-ammonium iodide, NHg,I, is formed in testing for
ammonia by means of Nessler’s reagent (which see).
3. Pass hydrogen sulphide through a mercuric solution
until the liquid smells strongly of the gas; a black precipi-
tate of mercuric sulphide, Hgs, is produced.
HgCl, + HS = 2HCl + HgS
Mercuric yarogse Hydorchloric $Mercuric
vhloride sulphide acid sulphide
Mercurie sulphide does not dissolve in dilute acids or in
ammonium hydrosulphide. In the case of mercuric chloride
(or of other mercuric salt to which hydrochloric acid has been
added previously), hydrogen sulphide, when added in small
quantity, produces a white precipitate. On the addition of
more of the reagent, the color of the precipitate changes
through various shades of yellow, orange, and brown, to black.
The same white substance may also be obtained by heating a
small quantity of black mercuric sulphide with solution of
mereuric chloride. Its composition is represented by the
formula, HgCl,, 2HgS. The yellow, orange, and brown sub-
stances are intermediate in composition between this and mer-
euric sulphide.
Note.—Hydrogen sulphide also yields a black precipitate with
solutions of mercurous salts. In the case of these salts, the pre-
cipitate consists of a mixture of mercuric sulphide and mercury
(not of mercurous sulphide); hence this reagent does not distin-
guish between mereurous and mercuric salts. But in the course
of systematic analysis, mercuric salts are precipitated from their
ey aa sulphide, after mercurous salts have been removed
as ch G.
Red Meveuric Sulphide.—Prolonged contact with hydrogen sul-
puss ch hydrosulphide, especially if warm, converts the black
to a red sulphide. Vermilion is mercuric sulphide prepared by
sublimation ’
Ethiop's Mineral, formerly known as Hydrargyi Sulphuretum
eum Sulphure, is a mixture of mercuric sulphide and sulphur,
obtained by triturating the elements in « mortar till globules of
mercury are no longer visible. [ts name is probably in allusion
to its color. |
220 THE METALLIC RADICALS,
Analytical Reactions of Merewrous Salts.
1. To a solution of a mercurous salt (the mercurous nitrate
obtained in experiment 2, for example) add hydrochloric acid
or other soluble chloride; a white precipitate of merenrous
chloride, calomel, HgCl, is produced.
2. To a solution of a mercurous salt add a few drops of a
very dilute solution of potassium iodide; a yellow precipitate
of mercurous iodide, HgI, is produced.
HigNO, + KI = KNO, + Hgt
Mereurous Potassium Potassium Mercurous
nitrate iodide nitrate iodide
Unless very dilute solution of potassium iodide is employed, it is
difficult to obtain a pure yellow precipitate, a greenish mixture of
mercurous iodide and mercury being generally formed, owing to
the decomposition of some of the former by excess of potassium
iodide ; a considerable excess completely decomposes the mer-
curous iodide, forming potassium mercuric iodide and mercury.
2Hgl + KI = KHgl, + Hg
The potassium mercuric iodide is soluble in water, and forms a
nearly colorless solution, while the metallic mercury remains as a
black percipitate.
3. To a mercurous salt, dissolved or undissoloved (e. g.,
calomel), add ammonia water; a black mercuros-ammonium
salt (¢. g., chloride, NH,Hg,Cl), is formed. It seems probable
that the so-called mercuros-ammonium salts are really mix-
tures of the mercuri-ammonium compounds (see p. 218) with
metallic mereury.
Other Tests for Mercury Compounds,
The elimination of mercury in the actual state of metal by
the copper test, coupled w iththe production or non-production of
a white precipitate on the addition of hydrochlorie acid to the
original solution, is usually sufficient evidence of the presence
of mereury and of its existence as a mercurous or a mercuric.
salt. But other tests may sometimes be applied with pig
tage. Thus metallic mercury is deposited on placing a
of the solution on a gold coin and touching the dro me:
the edge of the coin simultaneously with a key: ane acts
current passes, under these circumstances, from the gold to
the key, and thence through the liquid to the gold, decom-
posing the salt, the mercury of which forms a white metallic
MERCURY. 221
spot on the gold. This is called the ga/vanie teat, and is useful
for clinical purposes.—Solution of stannous chloride, SnCl,,
from the readiness with which it forms stannic chloride,SaCl,,
gives with mercuric solutions a white precipitate of mercurous
chloride, and rapidly reduces this mercurous chloride still
further to a grayish mass of finely divided mercury; this is
the magpie test, probably so-called from the white and gray
appearance of the precipitate. The reaction may also be
obtained from even such insoluble mercury compounds as
white precipitate—A confirmatory test for mercuric and
mereurous salts will be found in the action of solution of
potassium, sodium, or calcium hydroxide. (See pp, 216, 217.)
—Potassium chromate, K,CrO,, gives with mercurous salts,
a red percipitate of mercurous chromate, Hg,CrO,—Mer-
cury and all its compounds are more or less completely vola-
tilized when heated in a dry tube, many of the latter being
decomposed and yielding globules of metallic mereury,—
All dry compounds of mereury are decomposed when heated
in a dry test-tube with dried sodium carbonate, mereury sub-
liming and condensing in visible globules, or as a whitish
deposit which yields globules when rubbed with a glass rod.
Antidote-—Albumin gives a white precipitate with solu-
tions of mercuric salts ; hence the importance of administering
white of egg, while waiting for a stomach-pump or stomach-
siphon, in case of poisoning by corrosive sublimate.
QUESTIONS AND EXERCISES.
Name the chief ore of mercury, and describe a process for the extrac-
tion of the metal. —Give the properties of mercury.—In what state docs
mercury exist in “Gray Powder ''?—What other preparations of metallic
meroury itself are employed in medicine ?—State the relation of the
mercurous to the mercuric compounds.—Distinguish between an alloy
and an amalgam.—State the formule of the two mercury iodides,—Under
what circumstances has mereuric iodide different colors ?—Illustrate the
chemical law of Multiple Proportions as explained by the atomic theory,
oying for that purpose the stated composition of the two mercury
jodides.—Write down the formulm of Mercurous and Mercurie Nitrates
and Sulphates.—How is Mercuric Sulphate prepared ?—What is the
formula of “ Turpeth Mineral” ?—Describe the processes necessary for
the conversion of mercury into Calome! and Corrosive Sublimate, using
Why is black maganese oxide sometimes mixed with the
a conn pce pe in the preparation of corrosive sublimate?—Give the
and physical points of difference between calomel and corrosive
sublimate.—How may calomel in corrosive sublimate be detected ’—
Calenlate how much Mercury will be required in the manufacture of one
ton of Calomel. Ans. 17 cwt, nearly.— Mention the official preparations:
of the Mereury Chioride,—Give the formule and mode of formation
222 THE METALLIC RADICALS.
of the Red, Yellow, and Black Mercury Oxides, employing _—
Explain the action of the chief general test for Mercury.—How are
mercurous and mercuric salts analytically distinguished ?—Give a gehen:
ble view of the constitution of Hydrargyrum Awmoniatam, U.S. P., and
an equation showing how it is made,—State the best temporary antidote
to poisoning by mercury.
LEAD: Pb, Atomic weight, 205.35.
Occurrence. —The ores of lead are numerous; but the one from
which the metal is chiefly obtained is lead sulphide, PbS, galena
(from yaajvy, galén?, tranquility, perhaps from its supposed effect
in allaying pain.)
Preparation.—T he ore is first roasted in a current of air; much
sulphur is thus burnt off as sulphurous anhydride, while some of
the metal is converted into oxide; a portion of the sulphide is at
the same time oxidized to sulphate. Oxidation is then stopped and
the temperature raised, whereupon the oxide and sulphate, inter-
acting with undecomposed sulphide, yield the metal and sulphur-
ous anhydride; — 2PbO+PbS=3Pb+-80,; and PbSO,4+ PbS=
2Pb+ 28 230,.
Uses.—The uses of lead for making pipes and lead sheeting
are well known. Alloyed with some arsenic, it is used in making
ordinary shot; with tin it forms solder; with antimony and tin,
type-metal, and in smaller quantities it enters into the composition
of Britannia metal, pewter, and other alloys. Lead is so slightly
attacked by many dilute acids that chemical vessels and instru-
ments are sometimes made of it. Hot hydrochloric acid slo rosy!
converts it into lead chloride with evolution of hydrogen. Col
sulphuric acid in presence of air only very slightly attacks it with
formation of lead sulphate and water; hot concentrated sulphuric
acid attacks it rapidly with formation of lead sulphate and evolu-
tion of sulphurous anhydride. Hot nitrie acid converts it into
lead nitrate with evolution of nitric oxide,
The lead salts used in pharmacy and all other lead p
are obtained, directly or indirec tly, from the metal itself, Heated
to a high temperature in a current of air, lead combines with
oxygen and forms lead oxide, PbO, a yellow powder (masgicof), or,
if fused and solidified, a bela reddiah-y ellow, heavy mass of
bright scales (Plumbi Oxidum, U. 8. P.), termed litharge (from
Aidioc, lithos, a stone, and dpyrpoc, arguros, silver), Tt is from this
oxide that the chief lead compounds are obtained, Lead oxide,
by further heating in « current of air, at a temperature considerably
below that at which it was produced, yields ved lead or minium,
Pb.O,. The latter oxide is intermediate in composition between
lead oxide, PbO, and lead peroxide, PbO,; and, al it is
tustially represented by the formula Pb,O,, it is subject sone
variation in composition. Both litharge und red lead are much
LEAD. 223
used by painters, paper-stainers aud glass-manufacturers. White
lead is lead hydroxycarbonate, 2PbCo,, Pb(OH),; it is made by
exposing lead, cast in spirals or little gratings, to the action of air,
acetic acid fumes, and carbonic anhydride, the latter generated
from decaying vegetable matter, such as spent tan: lead oxyacetate
slowly but continuously forms, and is as continuously decom-
posed by the carbonic anhydride, with production of hydroxy-
carbonate, or dry white lead. Lead hydroxycarbonate is also
also made by bringing carbonic anhydride and litharge together
in a solution of lead acetate. Ground up with about 7 percent.
of linseed-oil, it forms the white lead used by painters and
plum bers.
Lead compounds are poisonous, producing saturnine colic, and
even paralysis. These effects are termed saturnine from an old
name of lead, Saturn, The alchemists called lead Saturn, first,
because they thought it the oldest of the seven then known metals,
and it might therefore be compared to Saturn, who was regarded
as the father of the.gods; and, secondly, because its power of
dissolving other metals recalled a peculiarity of Saturn, who was
said to be in the habit of devouring his own children.
Lead Acetate.
Experiment 1.—Place a few grains of lead oxide in a test-
tube, add about an equal weight of water and two and a half
times its weight of acetic acid, and boil; the oxide dissolves
and forms a solution of lead acetate, Pb(C,H,O,),. When
cold, or on evaporation if much water has been used (the
solution being en faintly acid), crystals of lead acetate
Plumbi Acetas, U.S. P,), Ph(C,H,0,),, 3H,O, are deposited.
lacs quantities are obtained by the same method.
PbO + 2HC,H.O, = Pb(C,H,0,), + H,O
oxide
Acetic acid ¢- Lead acetate Water
The salt is termed Sugar of Lead, from its sweet taste.
Lead Subacetate or Oxyacetate.
2.—Boil lead ncetate with four times its weight
of water and rather less than two-thirds of its weight of lead
oxide; the filtered liquor is solution of lead subacetate,
Liquor Plimbi Subacetatis, U.S. P., Goulard’s Extract. It
should contain 25 percent. of lead subacetate Pb,O(C,H,0,),.
A similar solution was used by M. Goulard, who drew attention
o it In 1770 and called it Ertractuin Saturni. A more dilute
solution, 1 of Liquor in 24 of distilled water, is also official under
THE METALLIC RADICALS,
the name of Liquor Plumbi Subacetatis Dilutus, The latter is
commonly known as Goulard water, Ceratum Plumbi Subacetatis,
a modification of the original Goulard’s Cerate, is official.
Lead Nitrate.
Experiment 3.—Digest a few grains of ved lead in dilute
nitric acid ; Jead nitrate, Ph( NO,),, is formed, and remains in
solution, while lead peroxide, PbO,, remains behind as a
dark brownish-purple powder. Lead Nitrate may be made
more directly by dissolving hitharge, PbO, in nitric acid.
PhO+2HNO,—Pb( NO,),+-H,0.
Lead nitrate or acetate is used in preparing lead iodide. For
this purpose the above mixture may be filtered, the lead peroxide
washed with hot water, the filtrate and washings evaporated to dry-
ness to remove excess of nitric acid, the residual lead nitrate redis-
solved by boiling with « small quantity of hot water, and the solu-
tion set aside to crystallize; or a portion may at once be used for
the nextexperiment, Lead nitrate, Pluméi Nitras, U. 8. P., forms
white crystals derived from octahedra.
Lead peroxide, PbO,, when heated with concentrated hydro-
chloric acid yields lead chloride, PbCl,, chlorine, and water.
PbO, +- 411C]l = PbCl, +. Cl, + 2H,0.
Lead Iodide. :
Experiment 4.—To a neutral solution of lead nitrate add
solution of potassium iodide; a precipitate of lead iodide, Phi
(Plumbi Iodidum, U. 8, P.), 18 produced. Equal weights o
the salts may be used in making large quantities.
PR(NO,), + 2KI = Pbl, + 2KNO,
Lead nitrate Potassium jodide Lead iodide Potassium nitrate
Heat the lead iodide with the supernatant liquid, and filter if
necessary ; the salt dissolves, and separates again in golden
cry stulline scales as the solution cools.
Lead iodide is soluble in solution of ammonium chloride.
Lead Oleate.
Experiment 5.—Boil together in a small porcelain dish a
few grains of a very finely powdered lead oxide, with twice
its weight of olive-oil, and also two or three times its weight
of water, well stirring the mixture, and from time to time
replacing water that has evaporated; the product 1s a white mass
of lead oleate, Pb(C\,H,,0,),, glycerin remaining in solution.
9739"
LEAD. 225
sPhO + 3H,O + 20,H,(C,H,0,),
Lead oxide Water Glyceril oleate (Wlive-oil or oleine)
a MONO) 86+
Lead oleate (lead plaster)
This action between the lead oxide and olive-oil is slow, requiring
several hours for its completion.
Lead Plaster (2mplastrum Plumbi, U. 5. P.) consists of practi-
cally pure lead oleate prepared by the interaction of lead acetate
with solution of soap (made from olive-oil).
odes of formation of Chloride, Sulphide, Chromate, Sul
Hydroxide, and other lead compounds ure incidentally feseribed in
the following analytical paragraphs.
' H,(O Ht),
poe at, me ont (glycerin)
Analytical Reactions of Lead Salta,
1. To a solution of a lead salt (acetate, for example) add
hydrochloric acid; a white precipitate of lead chloride, PbCl
is obtained. Boil the precipitate with a moderate quantity of
water ; it dissolves, but is redeposited in small acicular crystals
when the solution coola Filter the cold solution, and pass
cue su srs through it; the formation of a black pre-
itate of lead sulphide, PbS, shows that the lead chloride is
= ble to a slight extent in cold water.
Note.—The formation of a white precipitate (soluble in hot
water and blackened by hydrogen sulphide) on the addition of
hydrochloric acid, sufficiently distinguishes lead salts from those
of other metals; but the non-production of such a precipitate does
not prove the absence of a small quantity of lead since chloride is
slightly soluble in water.
2. Through a dilute solution of a lead salt, acidulated with
hydrochloric acid, hydrogen sulphide; a black precipitate
of lead sulphide, P PbS, is produced.
Lead in Water.—The foregoing is a very delicate test. Should
a trace of lead be present in water used for drinking purposes, it
sae be detected by means of hydrogen sulphide. On passing the
a pint of such (acidulated) water, a brownish color is
produced If the tint is scarcely perce eptible, set the liquid aside
a day; the hydrogen sulphide will undergo oxidation and a
phur will be found at the bottom of the vessel,
white no lead sulphate be present in it, but more or less brown
if it contain lead sulphide. Hygienists regard one-twentieth of a
gate at? of lead per gallon as dangerous, while a smaller quantity may
ater commonly used for drinking purposes should
not contain a trace.
226 THE METALLIC RADICALS,
8. Toa solution of a lead salt add ammonium hydrosul-
phide ; a black precipitate of lead sulphide, insoluble in
excess ; is produced,
4. To a solution of lead salt add solution of potassium
chromate, K,CrO,,; a yellow precipitate of lead chromate,
PbCrO p is formed, insoluble in dilute acids and in solution of
ammonium chloride.
Chromes.—This reaction has technical as well as analytical
interest, The precipitate is the common pigment termed chrome
yellow, or lemon chrome. Boiled with slaked lime and water, a
portion of the chromium is removed, together with oxygen, and
forms calcium chromate, while lead oxychromate, of a bright
orange-red color (chrome orange) is also produced, 2PbCrO, +
Ca(OH), = CaCrO, + Pb,OCrO, + H,0,
5. To a solution of a lead salt add dilute sulphuric acid, or
a solution of a sulphate; a white precipitate of a lead sulphate,
PbSO,, is produced.
Lead sulphate is slightly soluble in concentrated acids, and in
solutions of some potassium and sodium salts; it is insoluble in
acetic acid. It is readily dissolved by solution of ammonium ace-
tate, the resulting liquid yielding the ordinary reactions with
soluble chromates and iodides, It also dissolves readily in solution
of ammonium tartrate in presence of ammonia. .
In dilute solutions the above reaction with sulphurie acid or a
soluble sulphate does not take place immediately; the precipitate,
however, is produced after a time; its formation may be hastened
by ev aporating the mixture nearly to dryness and then diluting, or
by adding to the mixture its own ‘volume of alcohol.
The white precipitate often noticed in the vessels in which dilute
commercial sulphuric acid is kept, is lead sulphate derived from
the leaden chambers in which the acid is made, Its solubility in
concentrated and its insolubility in dilute sulphurie acid explains
its precipitation.
Antidotes —From the insolubility of lead sulphate in water, the
best antidote, in a case of poisoning by the acetate or other soluble
lead salt, is a soluble sulphate, such as Epsom salt, sodium sul-
phate, or alum, vomiting also being induced, or ‘the stomach-
pump, or stomach-siphon, applied as quickly as possible,
Other teats for lead will be found in the reactions with potas-
stum todide (see p, 994): with alkali-metal carbonates, which
produce white hydroxycarbonate, 2P he ‘O,, Ph(OH ),, insoluble
in excess ; with alkalies, which yield a white precipitate of lead
hydroxide, Pb(OH),), more or less soluble in excess, and
with alkali- metal phosphates, & dreenates, Serrocyanides, and
BISMUTH. 227
eyanides, which form compounds mostly insoluble, but of no
special analytical interest. Insoluble salts of lead may be
lissol ved by solution of potassium hydroxide or sodium brdres-
ide, NaOH.
The metal is precipitated in a beautifully crystalline state
by introducing metallic zinc (and some other metals) into a
solution of a lead salt; the /ead-tree is thus formed.—Solid
lead compounds are reduced when heated by the blowpipe-
flame in a small cavity in a piece of charcoal, a soft, malleable
head of metal heing produced, and a yellowish ring of lead
oxide deposited on the charcoal.
QUESTIONS AND EXERCISES.
Write down equations representing the smelting of galena.—Mention
some of the alloys of lead.—How is litharge produced ?—Give the form-
tile of white lead and red lead.—Describe the manufacture of white lead.
—Draw a diagram showing the formation of Lead Acetate.—Describe the
reparation and composition of Liquor Plumbi Subacetatis, U.S, P.—What
{s the action of nitric acid on red lead litharge and lead ?—Mention the
chief tests for lead.—How would you search for soluble compounds of
lead in a domestic water supply ?—What is the composition of chrome
ellow and of chrome orange *—Name the best antidote in cases of poison-
ng by lead salts, and explain its mode of action,
BISMUTH: Bi. Atomic weight, 206.9.
Occurrence,—Bismuth occurs in the metallic state in nature,
It is freed from udherent quartz, etc., by simply heating, when the
metal melts, runs off, and is collected in appropriate vessels. It
is also met with in combination with other elements; most com-
monly, as oxide, Bi,O,, in bismuth ochre ; sometimes, as sulphide,
BiS,, in bismuth glance. Bismuth is grayish white in color, In
its general chemical relationships it is allied to the elements of the
antimony and arsenic group, although in its analytical behavior
it is more closely related to lead and copper.
ification, —Arsenic may be removed from melted bismuth
by stirring it with an iron rod, iron arsenide rising to the surface
of the mass: antimony by stirring in some bismuth oxide, when
antimony oxide separates. Other metals present in bismuth,
expecially copper, are converted into sulphides, while bismuth is
not affected, by fusing the crude metal with about five percent. of
potassium cyanide, and two percent. of sulphur, the whole being
well stirred for w quarter of an hour with a clay rod (stem of a
tobacco-pipe). On pouring off the metal from the flux, and
228 THE METALLIC RADICALS.
melting and stirring it with five percent. of a mixture of potassium
and sodium carbonates, sulphur and traces of other impurities ure
removed, and the metal is obtained pure.— Tamm.
Uses, —Beyond the employment of some of its compounds in
medicine, bismuth is but little used. Melted bismuth expands
considerably on solidifying, and hence is valuable in taking sharp
impressions of dies. It is a constituent of some kinds of type-
metal and of pewter-solder,
Bismuth Nitrate.
Experiment 1.—To a few drops of nitric acid and an equal
quantity of water, in a test-tube, add a small quantity of
powdered bismuth, heating the mixture if necessary; nitric
oxide, NO, escapes, and solution of bismuth nitrate, Bi(NO,),,
results.
Bi 4HNO, = _ Bi(NO,) O
piemuth’ sco uct — sesame whee ae: ania woe
The solution, on evaporation, gives crystals, Bi(NO Bebo a
any arsenic which the bismuth may have contained
the mother-liquor.
To make bismuth nitrate, oxynitrate, oxycarbonate (or other
salts) on a larger scale, 2 ounces of the metal, in small fragments,
are gradually added to a mixture of 4 fluid ounces of nitric acid
and 3 of water, and, when effervescence (due to escape of nitric
oxide) has ceased, the mixture is heated for ten minutes, poured
off from any insoluble matter, evaporated to 2 fluid ounces to
remove excess of acid, and then either set aside for crystals of
nitrate to form, or poured into half a gallon of water to obtain
bismuth oxynitrate, or into a solution of 6 ounces of ammonium
carbonate in a quart of water to form oxycarbonate, as described
in the following experiments.
The precipitates should be washed with cold water and dried
at a temperature not exceeding 150° F. (65.5° C.). Exposed in
the moist state to 212° F, (100° C.) for any considerable time,
they undergo slight decomposition,
Bismuth Subnitrate or Oxynitrate.
Experiment 2.—Pour some of the above solution of bismuth
nitrate into a considerable quantity of water; decomposi
occurs, and a precipitate (of somewhat varying chemical com-
position ) consisting of bismuth oxynitrate and hydroxynitrate
is produced ( Bismutht Subnitras, U. S. P.). The formation
of bismuth oxynitrate is represented by the following
equation :—
BISMUTH.
= BiONO, + 2HNO
Bismuth oxynitrate Nitric acid
Bi(NO
é HO
Bismuth diet Water
Filter, and test the filtrate for bismuth by adding excess of
sodium carbonate; the formation of a precipitate shows that some
bismuth still remains in solution,
Decomposition of bismuth nitrate by water is the ordinary pro-
cess for the preparation of bismuth oxynitrate for use in medicine.
For this purpose the original metal must contain no arsenic. In
manufacturing the compound, therefore, before pouring the solu-
tion of nitrate into water, the liquid should be tested for arsenic
by one of the hydrogen tests; if that element be present, the solu-
tion must be evaporated, and only the deposited crystals be used
in the preparation of the oxynitrate. This must be done because
on pouring an arsenical solution of bismuth nitrate into water, the
arsenic is not wholly removed in the supernatant liquid unless the
oxynitrate be redissolved and reprecipitated several times, accord-
ing to the amount of arsenic present.
Bismuth submitrate is gradually decomposed by solutions of
alkali-metal carbonates (also by the bicarbonates, with production
of carbonic anhydride), bismuth oxycarbonate and the alkali-
metal nitrate being formed.
Bismuth Oxysalts,—On pouring a solution of bismuth chloride,
BiCl,, into water, bismuth oxychloride, BiOCl, is produced (a
white powder used as a cosmetic, ‘‘ pearl-white’’ (Blane de Perle),
also in enamels and in some varieties of sealing-wax). Bismuth
bromide, BiBr,, and iodide, Bil, similarly treated, yield oxy-
bromide, BiOEr, and oxyiodide, BiOI. The subnitrate is, there-
fore, probably an analogous compound, an oxynitrate, BiONQO,,
Bismuth sulphate, Bi,(5O,),, is also decomposed when placed in
water, giving bismuth oxysulphate, Bi,O,SO,.
It is difficult to prove whether or not the water in hydrous bis-
muth oxynitrate, BiIONO,,H,0, isan integral part of the salt. If
it is, the compound is probably bismuth hydroxynitrate,
Bi(OH),NO,,
Bismuth Oxide.
Experiment 3.—Boil bismuth subnitrate with solution of
sodium hydroxide for a few minutes; it is converted into
yellowish bismuth oxide, Bi,O,.
2BiONO, + 2NaOH = Bi,O, + 2NaNO, + H,O
Mamuth — Sodium Bismuth Sodium Water
ox | s
230 THE METALLIC RADICALS,
Bismuth Subcarbonate or Oxycarbonate.
Experiment 4.—To a solution of bismuth nitrate add solu-
tion of ammonium carbonate; a white precipitate of hydrous
bismuth oxycarbonate, (Bismuthi Subcarbonas, U. 8. P.), is
produced, of somewhat varying composition, but approximating
to the formula, 2Bi,O,CO,, H,O.
2Bi(NO,), + 2N,H,,C,0,+ H,O = 6NH,NO,+ Bi,0,CO,+ 800
Bismuth “ \iamonium Ammonium Bismuth Carbonic
nitrate carbonate" nitrate oxycarbonate anhydride
This compound may be regarded as similar in constitution to
the oxysalts just described which are commonly looked upon as
salts of a hypothetical radical bivmuthy! (BiO).
Bismuth Citrate.
Experiment 5.—Heat 4 parts of Bismuth Subnitrate and 3
parts of citric acid with 16 parts of water on a water-bath,
with frequent stirring, until a drop of the mixture yields a
clear solution with arama water. Then add 200 ree of
water. The precipitate, after thorough washing, and drying
at a gentle heat, is Bismuth Citrate, BiC,H,O,, (Bismuthi
Citras, U.S. P.). |
Experiment 6.—To bismuth citrate, rubbed into a smooth
paste with water, and heated on a water-bath, add ammonia
water until the salt is dissolved and the liquid is neutral or
only faintly, alkaline, and filter. The solution, evaporated
to a syrupy consistance and spread on glass plates yields when
dry, Bismuth and Ammonium Citrate, ( Bismuthi et Ammonii
Citras, U. 8. P. ) in seales.
Bismuth Subsalicylate.
Experiment 7.—To a solution of bismuth nitrate add a
solution of sodium salicylate; a white precipitate of bismuth
subsalicylate, C LH, .OH.COO.BiO (Bismuthi Subsatieylaa,
U.S. P.), is produced.
Bismuth Subgallate.
Experiment 8,—To a solution of 3 parts of crystallized bis-
muth nitrate in 20 parts of dilute acetic acid (1 part of
glacial acetic acid to 2} parts greater) add a solution of 1
part of gallic acid in 45 parts of water; a bright yellow pre-
BISMUTH.
* cipitate of bismuth subgallate ( Bismuthi Subgallas, U.S. P.),
is obtained, which is of somewhat variable chemical composi-
tion,
Analytical Reactions of Bismuth Salts.
1. Through a solution of a bismuth salt (a slightly acid
solution of nitrate, for example) pass hydrogen sulphide; a
black precipitate of bismuth sulphide, Bi,S,, is produced,
Add ammonia water (to neutralize the acid) and then ammo-
nium hydrosulphide; the precipitate, unlike As,S, and Sb,8,,
is insoluble.
2, Concentrate almost any acid solution of a bismuth salt
and pour into much water containing some sodium or ammo-
aba chloride; a white precipitate of bismuth oxychloride
results.
This reaction is characteristic of bismuth salts. Bismuth oxy-
chloride is especially insoluble in water, and is distinguished from
antimonious oxychloride by being insoluble in solution of tartaric
acid.
3. To a solution of a bismuth salt add caustic alkali; a
White precipitate of bismuth hydroxide, Bi(OH),, is produced,
insoluble in excess, and becoming yellowish on boiling.
4. First prepare a reagent as follows :—Dissolve 1 grain of
lewd acetate in 3 ounces of hot water and add 30 drops of acetic
acid; dissolve 60 grains of potassium iodide in 3 ounces of
water ; mix the solution; on cooling, lead iodide is deposited
in the characteristic yellow crystalline plates or scales. Next,
place some of the reagent (crystals included) in a test-tube
and heat gradually till solution takes place. Any liquid con-
taining, or supposed to contain, bismuth is then added, and
the whole allowed to cool. ‘The separated scales will show a
distinet change in color from the original yellow to dark orange
or crimson, according to the quantity of bismuth present.
Test for calcium phosphate in bismuth salts.— Dissolve the
powder in nitric acid add about twice its weight of citric acid
and sufficient ammonia to give decided alkalinity ; then boil,
keeping the mixture faintly alkaline with ammonia ; bismuth
remains in solution, and calcium phosphate is prec ipitated,
Tests for other impurities in bismuth or its salts.— Dissolve
in nitric acid ; concentrate and set aside for c rystals of bismuth
nitrate to separate ; pour off the mother- liquor, ¥ whie h will con-
tain wny impurities in a concentrated form. If this ‘mother-
232 THE METALLIC RADICALS,
liquor be evaporated with hydrochloric acid until all the
nitrie acid is dissipated, a little of the product should yield no
evidence of arsenic on being examined by Marsh’s test ; no
blue coloration on adding water and excess of ammonia (cop-
per), and no precipitate on filtering and saturating the ammo-
niacal filtrate with nitric acid (silver); no white precipitate
with dilute sulphuric acid (lead); no red or black precipitate
with sodium sulphide (tellurium or selenium); and no blue
precipitate with potassium ferrocyanide (iron),
CADMIUM: Cd. Atomic Weight, 111.6.
Tn most of its chemical relations cadmium resembles zinc. In
nature it occurs chiefly as an occasional constituent of the ore of
that metal. In distilling zine containing cadmium, the latter,
being the more volatile, passes over first. In analytical operations
cadmium, unlike zinc, comes down among the metals precipitated
by hydrogen sulphide ; that is, its sulphide is insoluble in highly
dilute hydrochloric acid, while zine sulphide is soluble. It is a
white malleable metal which boils at 770° C. Sp. gr, 8.6 at
15.5° C.
Beyond the occasional employment of the sulphide asa pigment
(jaune brilliant), and of the iodide and bromide in photography,
cadmium and its salts are but little used.
Cadmium Iodide.
Experiment,— Digest together, in a flask, metallic cadmium,
warm water, and iodine, until the color of the iodine disap-
pears ; solution of cadmium iodide, Cdl, remaims. Glistening
white crystalline scales may be obtained on evaporating the
solution.
This salt is employed with other iodides in iodizing collo-
dion for photographic use. It readily melts; and it is soluble
in water or alcohol, the solution reddening litmus,
Analytical Reactions of Cadmium Salts,
1. Through a solution of a cadmium salt (CdI, or CdCl.)
pass hydrogen sulphide; a yellow precipitate of cadmium eul-
phide, CdS, is produced, resembling in appearance arsenous,
arsenic, and stannic sulphides. Add ammonium hydrosul-
phide; the precipitate, unlike the sulphides just mentioned,
does not dissolve. It dissolves easily in hot dilute hydrochlori¢
or sulphurie acid,
SILVER, 233
Cadmium and cupric sulphides may be separated by means of
solution of potassium cyanide, in which cupric sulphide is soluble
and cadmium sulphide insoluble.
2. To a solution of a cadmium salt add solution of potas-
sium hydroxide; a white precipitate of cadmium hydroxide,
Cd(OH),, is produced, insoluble in excess of the precipitant.
Zinc hydroxide, ee arith precipitated under similar circum-
stances, is soluble in solution of potassium hydroxide; the filtrate
from the cadmium hydroxide may therefore be tested for any zinc,
present as an impurity, by adding hydrogen sulphide or ammonium
hydrosulphide, Zine and cadmium hydroxides are soluble in
excess of ammonia water.
Before the blow-pipe flame, on charcoal, cadmium salts give a
brown deposit of cadmium oxide, CdO,
QUESTIONS AND EXERCISES,
How does bismuth occur in nature ?—Whuat is the quantivalence of bis-
muth ?—Write equations descriptive of the action of nitric acid on bis-
muth, and water on bismuth nitrate.—How may arsenic be excluded from
bismuth salts?—Give an equation illustrating the process for the prepara-
tion of bismuth carbonate.—Mention the tests for bismuth.—In what con-
dition does cadmium occur in nature ?—By what process may cadmium
iodide be prepared ?—Mention the chief test for cadmium.—Distinguish
cadmium stilphide from sulphides of similar color.—How is cadmium
separated from zinc ?
SILVER: Ag. Atomic weight, 107.12.
Ocourrence.—This element occurs in nature in the metallic state;
and also combined with sulphur as silver sulphide, Ag,S, asso-
ciated with much lead sulphide, forming argentiferons galena,
wation,—The lead obtained from argentiferous galena is
melted and slowly cooled; crystals of nearly pure lead separate
first and are rak
roasted in a current of air, whereby the lead is oxidized and
removed as litharge, while pure silver remains. Other ores undergo
vurious ry treatments according to their nature, and sare
then shaken with mercury, which amalgamates with and dissolves
the particles of metallic silver, the mercury being subsequently
THE METALLIC RADICALS.
removed from the amalgam by distillation. Soil and minerals eon-
taining metallic silver are also treated inthis way. Animportant
improvement in the amalgamation process, by which the mercury
more readily unites with the silver, consists in the addition of a
small proportion of sodium to the mercury, . Silver chloride may
be dissolved from ores by solution of sodium thiosulphate,
Silver is not readily affected by the weak acid or other fluids of
food, though it is rapidly tarnished by sulphur and many sulphur
compounds, It does not perceptibly attack hydrochloric acid; it
reduces somewhat diluted nitric acid to nitric oxide, NO, silver
nitrate AgNO,, being formed; it also reduces hot sulphuric acid
to sulphurous anhydride, SO,, silver sulphate, AgSO,, being
formed. This latter salt is crystalline, and slightly soluble in
water,
Impure Silver Nitrate.
Experiment 1.— Dissolve a silver coin in nitrie aeid; nitric
oxide, NO, is evolved, and a solution of silver and cupric
nitrates is obtained.
Silver Coinage.—Pure silver is too soft for use as coin; it is
therefore hardened by alloying with copper. The silver coinage
of the United States contains 10 percent, of copper. British sil-
ver money contains 7.5, German 25, and French 10 and 16.5 per-
cent. of copper—for the fineness of the French standard silver is
0.900 in the five-franc piece, while an inferior alloy of 0,835 is
used for the coins of lower denominations, The one-frane piece,
composed of the latter alloy, is still made to weight five grammes,
the weight originally chosen for the franc as the unit of the mone-
tarv scale when the fineness of the coin was 0.900. It has now
become a token, of which the nominal value exceeds the intrinsic
value,
Silver Chloride.
Experiment 2.—To the product obtained in the preceding
experiment, add dilute hydrochloric acid or a solution of a
chloride ; a white precipitate of silver chloride, AgCl, is pro-
duced, copper still remaining in solution. Colleet the precipi-
tate on a filter and wash it with water; it is pure silver
chloride.
Notes. —The copper may also be separated by evaporating the
solution of the metals in nitric acid to dryness and gently heating
the residue, when the cupric nitrate is decomposed, but the silver
SILVER, 235
nitrate is unaffected. The latter may be dissolved out from the
residual cupric oxide by means of water.
Silver chloride may be obtained in crystals by evaporation of
its solution in ammonia water,
The usefulness of halogen salts of silver in photography depends
upon the fact that these compounds undergo a darkening on
exposure to light. According to Baker, this is due to the forma-
tion of an oxy-compound—in the case of the chloride, Ag,Clo.
Pure Silver.
Experiment 3.—Place the silver chloride obtained in experi-
ment 2 in a dish, wet it with dilute sulphuric acid, and lay
a piece of sheet zinc on the mixture; metallic silver is
precipitated and, after about one day, wholly removed from
combination. Collect the precipitate on a filter and wash with
water; it is pure metallic silver, and is readily fusible into a
single button, especially if mixed with a little borax and
nitre,
Note.—Any considerable quantity of silver chloride may be
reduced toa lump of the metal by fusion in a crucible, with about
half its weight of sodium carbonate, The chloride is also reduced
by boiling it with caustic alkali and grape sugar until a trial
sample is entirely dissolved by nitric acid.
Pure Silver Nitrate.
Experiment 4,— Dissolve the pure silver from experiment
3 in nitric acid (3 parts by weight of silver require about 2
or 24 of concentrated acid diluted with 5 of water), and
remove excess of acid by evaporating the solution to dryness
and slightly heating the residue; the product is pure silver
nitrate. Dissolve it by heating with a small quantity of
water; the solution on cooling, or on evaporation, deposits
colorless tabular erystals of silver nitrate.
SAg + 4HNO, = NO + B8AgNO, + 2H,0
Bilver Nitric acid Nitric oxide Silver nitrate Water
Notes.—Silver Nitrate (Argenti Nitras, U. 8. P.), treated with
4 parts of hydrochloric acid to every 100, melted at as low a
temperature as possible, and poured into proper r moul is, yields
the white cylindrical sticks or rods commonly termed canatic (from
anion, Aaid, T burn), /unar eauetic, or moulded silver. nitrate
(Argenti Nitras Fumus, U. S. P.). The alchemists called silver
236 THE METALLIC RADICALS,
Diana or Luna, from its supposed mysterious connection with
the moon. Mitigated Silver Nitrate, Argenti Nitras Mitigatus,
U.S. P., is a fused mixture of one part of silver nitrate with
two parts of potassium nitrate. :
The specimen of silver nitrate obtained in the foregoing experi-
ment, dissolved in water, will be found useful as an analytical
reagent. Silver nitrate dissolves in 90 percent, alcohol; but
decomposition occurs after a time.
Silver salts are decomposed when in contact with organic matter,
especially on exposure to light, or on heating, the metal itself
being liberated, or a black insoluble compound formed. Hence
the value of silver nitrate in the manufacture of indelible ink for
marking linen ; hence, too, the reason of the practice of rendering
silver solutions clear by subsidence and decantation, rather than
by filtration through paper; and hence the cause of those cases
of actual combustion which have been known to occur in preparing
pills containing silver oxide and essential oil or other organic
matter. Linen marked with silver marking-ink should not be
cleansed by aid of bleaching liquor, as the marked parts are then
apt to be rapidly oxidized and ‘‘tendered,’’ holes resulting,
Paul says the reaction is as follows: — Ag,O + CaCl,O, =
2AgCl + CaO + O.,
Silver Oxide.
Experiment 5.—''o a solution of silver nitrate add solution
of potassium or sodium hydroxide, or lime-water; an olive-
brown precipitate of silver oxide, Ag,O, is produced. The
washed and dried oxide, Argenti Oridum, U.S. P., is decom-
posed by the action of heat, with production of metal, It is
also reduced by contact with organic matter. (See preceding
paragraph. )
In preparing it calcium hydroxide is the precipitant usually
employed, potassium or sodium hydroxide not being so readily
removed by washing. Three and a half pints of good lime-water
will decompose half an ounce of silver nitrate,
2AgNO, + Ca(OH), = Ag,O + Ca(NO), + HO
Bilver Calcium Silver Calcium Water
nitrate hydroxide oxide nitrate
Silver oxide is also precipitated on adding ammonia water to a
solution of silver nitrate, but it is rapidly taken up by the
ammonium nitrate formed at the same time, arvent-ammoniunm
nitrate, NH.AgNO., probably being formed. The direct solution
of silver oxide in ammonia may give the highly explosive sub-
SILVER. | 237
stance known as Berthollet’s fulminating silver (? NH,Ag).
Ordinary fulminating silver, C/N,O,Ag,, results from the interaction
of silver nitrate, nitric acid, and alcohol. The corresponding
mercury compound, /ulminating mercury, C,N,O,Hg, is used in
Ne se caps. Silver Ammonium Nitrate Test-Solution is
o 2
Methods of forming several other salts of silver are incidentally
mentioned in the following analytical paragraphs.
Analytical Reactions of Silver Salts.
To a solution of a silver salt add hydrochloric acid or
other soluble chloride; a white curdy precipitate of silver
chloride, AgCl, is produced, Add nitric acid, and boil; the
precipitate does not dissolve. Pour off the acid and add
ammonia water; the precipitate dissolves. Neutralize the
ammoniacal solution by means of an acid; the white curdy
precipitate is reproduced.
This is the most characteristic test for silver. The precipitated
chloride is also soluble in solutions of sodium thiosulphate or
potassium cyanide—facts of considerable importance in photo-
graphic operations.
Other analytical reagents besides the above are occasionally
useful—H ydrogen sulphide, or ammonium hydrosulphide,
gives a black precipitate of silver sulphide, Ag.S, insoluble
in alkalies.—Solution of potassium or sodium hydroxide gives
a brown precipitate of silver oxide, Ag,O.—Sodium phosphate
gives a yellow precipitate of silver phosphate, Ag PO,, soluble
in nitric acid and in ammonia water—Ammonium arsenate
gives a brown precipitate of silver arsenate, Ag,AsO,, already
noticed in connection with arsenic acid.—Potassium bromide
gives a yellowish-white precipitate of silver bromide, AgBr,
insoluble in dilute acids, soluble with some difficulty in
ammonia.—Potassium iodide produces a pale-yellow precipi-
tate of silver iodide, AgI, insoluble in dilute acids.—It is
changed by ammonia into a yellowish insoluble compound.—
Potassium cyanide gives a white precipitate of silver cyanide,
AgON (Argenti Cyanidum, U. 8. P.), soluble in excess,
somewhat soluble in ammonia, insoluble in dilute nitric acid,
soluble in boiling concentrated nitric acid.—Potassium ehro-
mate, K.CrO,, gives a red precipitate of silver chromate,
238 _ THE METALLIC RADICALS.
Ag,CrO,.—Potassium dichromate gives a red precipitate of
silver anhydrochromate, Ag,Cr,O,.—Many organic acids give
rise to insoluble silver salts—Several metals displace silyer
from solution, mercury forming in this way a crystalline
precipitate known as the silver tree, or Arbor Dianw.—Heated
on charcoal with sodium carbonate in the blowpipe-flame,
silver salts yield bright globules of silver, not accompanied
by an incrustation as in the corresponding reaction with lead
salts; the experiment may be performed with the nitrate,
which first melts, and then, like all nitrates, deflagrates, yield-
ing a white metallic coating of silver which slowly aggregates
to a button.
Antidotes. —Solution of common salt, sal-ammoniac, or any other
. inert chloride should obviously be administered where large doses
of silver nitrate have been swallowed. A quantity of sea-water or
brine would convert the silver into insoluble chloride, and at the
same time produce vomiting,
QUESTIONS AND EXERCISES.
By what process is silver obtained from argentiferous lead ?—What
weight of U.S. silver coin will yield one pound of pure silver nitrate ?—
How may the metal be recovered from impure silver salts?—Give a
diagram showing the formation of silver uitrate.—Describe the reaction
of lime-water with silver nitrate —Mention the chief test for silver, and
state how silver salts may be distinguished from those of lead and mer-
cury.—Name the antidote for silver,
Qualitative Analysis.
Methods for the qualitative analysis of solutions containing any
or all of the metals, copper, mercury (either a8 mercurous or 4s
mercuric salt), tin (as stannous salt), lead, bismuth, cadmium, and
silver have now to be considered. Before introducing the student
to the systematic examination of solutions containing any or all
of the metals of general interest, treated of in this Manual, it will
be convenient to indicate how the particular metals just nientioned
above, are dealt with in that systematic examination, in 80 far as
dividing them into analytical groups is concerned.
The fi ret point to be noted is that silver and mercurous chlorides
are insoluble, and that lead chloride is only sparingly soluble, in
cold water, Addition of excess of hydrochloric acid, or other
soluble chloride, to the solution, cnuses the complete precipitation
QUALITATIVE ANALYSIS. 239
of silver and mercurous chlorides (or, if no precipitate forms, shows
the absence of those metallic radicals), and it may cause the pre-
cipitation of some lead chloride also, After removing any pre-
cipitate by filtration, part or the whole of the lead (if any was
present originally), and the whole of any of the other metals men-
tioned above, which may have been present, pass into the filtrate,
from which they can be precipitated by means of hydrogen sul-
hide,
; The fuct that this method of dividing these metals into two
groups for analytical purposes, is practically universally employed,
furnishes the explanation for the separate treatment of the metal-
lic radicals constituting the two groups, in the two pairs of pre-
liminary analytical schemes which follow (pp. 239, 242), The
first pair of schemes deal with silver, mercurous, and lead salts;
while the second pair deal with cupric, mercuric, lead, bismuth,
and cadmium salts, and partially with stannous salte.
The position of tin in this analytical arrangement is somewhat
anomalous, since, in the course of the systematic separation of the
metals, this element falls into the analytical group along with
arsenic and antimony, The connection of this latter group (the
arsenic group) with the group embracing copper, bismuth, etc.
(the copper group), will be evident later, when the scheme for
the systematic separation of the whole of the metals of general
interest comes to be discussed (p. 244),
DIRECTIONS FOR APPLYING SOME OF THE REACTIONS DES-
CRIBED IN THE FOREGOING PARAGRAPHS TO THE
ANALYSIS OF AN AQUEOUS SOLUTION OF A SALT OF ONE
OF THE METALS SILVER, MERCURY (AS MERCUROUS
SALT), LEAD,
Add hydrochloric acid :—
Silver is indicated by a white curdy precipitate, insoluble
in excess, easily soluble in ammonia water.
Mercurous salts is indicated by a white precipitate which
is turned black by ammonia water.
Lead is indicated by a white precipitate, insoluble in
ammonia water. Confirm by boiling a small portion
of the hydrochloric-acid precipitate in water; it dis-
solves.
If hydrochloric acid gives no precipitate, silver and mer-
eurous salts are absent, and lead can only be present in very
small quantity. The presence of lead in small quantity is
best detected by applying the sulphuric acid test to a fresh
THE METALLIC RADICALS.
portion of the original solution, the tube being set aside for a
time if the precipitate does not appear at once.!
TABLE OF SHORT DIRECTIONS FOR APPLYING SOME OF THE
REACTIONS DESCRIBED IN THE FOREGOING PARAGRAPHS
TO THE ANALYSIS OF AN AQUEOUS SOLUTION OF ANY OR
ALL OF THE METALS SILVER, MERCURY (AS MERCUROUS
SALT), LEAD.
Add hydrochloride acid in excess, filter, and wash the pre-
cipitate with a small quantity of cold water.
Precipitate
Pb Hg (ous) Ag
Wash on the filter with boiling water.
Residue Filtrate
Pb
Hg (ous) Ag
TA.OH. Add
Add sa go | HLSO,
- white ppt.
Residue Filtrate
. Ag
Hg |
(mercurous), black) Add HN, white ppt.
DIRECTIONS FOR APPLYING SOME OF THE REACTIONS DE-
SCRIBED IN THE FOREGOING PARAGRAPHS TO THE
ANALYSIS OF AN AQUEOUS SOLUTION OF A SALT OF ONE
OF THE METALS COPPER, MERCURY ( AS MERCURICSALT),
TIN (AS STANNOUS SALT), LEAD, BISMUTH, CADMIUM,
Note that solutions of cupric salts have # blue color.
Acidulate the liquid with hydrochloric acid and pass
' Liquids containing only a small quantity of lead do not readily
yield lead sulphate on the addition of sulphuric acid. Before lead can be
aril to be absent, therefore, the liquid should be evaporated to dryness
with one drop of sulphuric acid, and the residue digested in Water; any
lead sulphate then remains as a heavy, white, insoluble powder,
QUALITATIVE ANALYSIS. 241
hydrogen sulphide through it until the mixture, after shaking,
smells of the gas:—
Cadmium salts give a yellow precipitate, insoluble in
ammonia water easily soluble in hot dilute hydro-
chloric acid.
Cupric, mercuric, stannous, lead, and bismuth salts give
ark-brown or black precipitates. In the case of a
mercuric salt, the precipitate may be white or pale-yel-
low at first, but it rapidly becomes orange, brown, and,
finally, black. In the case of a lead salt, the precipi-
tate is sometimes reddish-brown if much hydrochloric
acid is present, but it becomes black on dilution of the
solution and addition of enough hydrogen sulphide.
To distinguish cupric, mercuric, stannous, lead, and bis-
muth salts from one another, add potassium iodide to another
portion of the original solution:—
A pale-brownish mixture (which really consists of a
nearly colorless precipitate of cuprous iodide in a
yellow or brown solution of iodine) indicates a cupric
salt. The brown color disappears and the precipitate
is seen to be nearly colorless, when solution of sul-
phurous acid is added Compare reaction 7, p. 208.
A yellowish-red precipitate, rapidly becoming bright-red,
soluble in excess of potassium iodide, indicates a mer-
curic salt.
The Feats of a pale-yellow precipitate, or, in dilute
solutions, of none at all, incicates a stannous salt.
A yellow precipitate, insoluble in excess of potassium
iodide, soluble in boiling water, indicates a lead salt.
A bright-yellow solution, or a brown precipitate which
dissolves in excess of potassium iodide to form a bright-
yellow solution, indicates a bismuth salt.
TABLE OF SHORT DIRECTIONS FOR APPLYING SOME OF THE
REACTIONS DESCRIBED IN THE FOREGOING PARAGRAPHS TO
THE ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF TWO
OR MORE OF THE METALS, COPPER, MERCURY (AS MERCURIC
SALT), LEAD, BISMUTH, CADMIUM.
Acidulate the liquid with hydroehloric acid and pass hydro-
gen ek through it until the mixture, after shaking
amells of the gas ; filter.
16
THE METALLIC RADICALS.
Precipitate
Cu Hg (ic) Bb Bi Cd
Wash with water; boil with HNO,; dilute with
water and filter.
|
Filtrate
Cu Pb Bi Cd!
Add NH,OH in excess, filter.
Residue
Hg (ic)
Black
Confirm by
Cu test
in original
solution
|
Filtrate
Cu Cd
(Blue ifCu present).
Add KCN in
excess, and pass
Precipitate
Pb fi
Wash ; dissolve on
filter ina few dro
of dilute HNO,
dilute, filter.
|
Filtrate
Cu
Acidify
with
aceticacid ;
brown
ppt
Filtrate
Pb
Add
HSO,
set nside ;
white P pt.
|
yellow
Ppt.
Bi
: white
|
—_—
Filtrate
Dilute with
H,S solution
so, as to
ensure
complete
precipitation
of
Pb, Bi, Cad,
h
the
sulphides of
which are to
some extent
soluble in
cold dilute
HCL
If any
further pre-
cipitate is
prodaved,
it may be
added to
the original
| precipitate,
or examined
separately.
The Analytical Classification of Metals,
Systematic Analysis.
The following Tables, giving directions for the analytical
examination of the solutions for the presence of practically any of
the metallic radicals hitherto considered, include and, to a certain
extent, epitomize the Tables previously given under the different
groups. The order of addition of the group-reagents is arranged
according to a carefully devised plan which is set forth in the
following outline of the annexed analytical Tables :—
‘The possible presence of tin, whether as stannous or stannic salt, is
not considered in the separation described here, since, in the systematic
examination of a solution which might contain tin, along with copper,
mercury, etc., any stannous or stannic sulphide is removed from the eu
ric, mercuric, ete., sulphides before the examination of the latter sulphides
if proceeded with. (See p. 244).
QUALITATIVE ANALYSIS.
OUTLINE OF THE ANNEXED ANALYTICAL TABLES.
HCI HS | NH,HS | (NH,),CO, |
howe
Od
(a5 mercu-
Teas enlt) Cu
Pb Hye
(partially) | (as mercuric
salt)
Hydroxides soluble
in NH,OH
| Ph
Ag (entirely)
Bi
As
(as arsenous
or arsenic
salt)
Sb
Sn
(as stan-
nous or
stannic
aalt)
Au
Pt
Insoluble in NH,SH.
Hyrdroxides insol.
in NH,OH
2
7 |
ti
Z
a
e
=
E
z
Note.—The student should practice the examination of aqueous solutions
of salts of the above metals, by aid of the Tables, until he is able to asver-
tain with facility and accuracy which metalic radicals are present, In
this way he will best perceive the peculiarities of each element, and the
gener! relations of the elements to each other,
The foregoing outline indicates that hydrochloric acid, which is
the first group-reagent added, precipitates silver and, mercurous
chlorides and partially precipitates lead chloride (unless the lead
solution is very dilute). The filtrate obtained on removing the
hydrochloric acid precipitate is next treated with hydrogen sul-
phide, which precipitates the metals of the copper and arsenic
roups together as sulphides. The sulphides of these two groups
have differently when digested with yellow ammonium hydro-
sulphide (or, what comes to the same thing, ammonium hydrosu!-
' See Experiment 5, p. 141. }
244 THE METALLIC RADICALS,
phide and a pinch of sulphur), those of the oof
solving in this reagent, while those of the copper group
undissolved. (See note on p. 242), Hence, when the
of the two groups have been precipitated together and ered of
the mixed precipitate is treated with yellow ammonium h
sulphide so as to effect the separation of arsenic group sul
from the copper group sulphides, while the filtrate still neal
the metals of the iron, zinc, and barium groups along with mag-
nesium and the alkali metals.
A very common mode of dealing with the filtrate ein the one
adopted in the annexed Tables) is to add excess of : and
then ammonium hydrosulphide to it. The ammonia int neutral
izes the hydrochloric acid present in the filtrate, form
ammonium chloride :—HCl + NH,OH = NH re +
soon as this action has been completed, it forms some amn
hydrosulphide with the excess of hydrogen sulphide present. This,
together with more ammonium hydrosulphide which is added,
precipitates, as sulphides or hydroxides, all the metals of the
iron and zinc groups. The ammonium chloride, formed by the
first interaction of the ammonia with the hydrochloric acid, pre-
vents the precipitation of magnesium at this stage, The metals
of the barium group, along with magnesium and the alkali metals,
pass into the filtrate. The barium group metals are su n
precipitated as carbonates by the addition of ammonium
ate ; and magnesium and, to some extent, lithium as
by means of ammonium phosphates, as already described on
128, where the mode of dealing with the other alkali-metals
also discussed. -
Of the accompanying Tables, the first includes directions oe Git
analysis of an aqueous or only slightly acid solution containing amy
salt, of any of the metals hitherto considered. Here the c
the precipitate or precipitates afforded by a metal given under
circumstances must largely be relied on in attempting the detectit
of the various elements.
The folded Table is intended as a scheme for the analysis:
solutions containing salts of more than one metal, Itis acon np ile
ation from the foregoing reactions and may often be altered)
varied in arrangement to suit the requirements of the wnalvt.
The analysis of solutions containing only one metal will we
impress the memory with the characteristic tests for the —
metals and other radicals, and familiarize the mind with eb
principles. More thorough analytical and general eher
knowledge is only acquired on working on such mixtures of bod cy
as are met with in actual practice, beginning with solutions whieh
may contain any or all of the members of a group (see previoul
pages), then examining solutions containing more than one gre
and finally analyzing liquids in which are dissolved se
of any of the common or rarer metals,
[To face page 245.
AN AQUEOUS OR ONLY SLIGHTLY ACID SOLUTION OF ORDINARY
» INTEREST. ‘
c) Cr Ba Ca Sr Mg Li K Na NH, . |
Filtrate
Co Ni Al Fe Cr Ba Ca Sr Mg Li K Na NH,
ld NH,Cl, NH,OH, NH,S8H, warm gently and filter.
Se eee eee eee
a Filtrate
\] Fe Cr Ba Ca Sr Mg Li K Na NH,
-h a few drops of HINO , Add (NH,),CO,, warm, filter.
tlir, filter.
Filtrate Precipitate Filtrate
Zn Mn Co Ni Ra Sr Ca Mg Li K Na NH
y with HUM 302, pass I1,S, Collect, wash, dissolve in ‘Add (R H,)gHAsU,, stir, filter
r.
HC, H,O4, add excess of!
KCr0,, filter.
a
Precipitate | Ppt. Filtrate
t. Filtrate
Zn Co Ni Ba Sr Ca Li K Na NH,
| Boil with Hl and a little | Yelluw. |Add dilute 11,SO,, White) Evaporate to small
| HNO s, add KOH, filter. — let stand, filter. bulk. Add NH,OH.
Filt. Precipitate Ppt. Filt. t. | Filtrate
zn Co Ni Sr Ca { |K Na NH,
: Add Dissolve in HCI, White Add See Evaporate,
NH,SH.| and proceed as NH,OH and p. 250. ignite, dissolve.!
White | directed on page KNEg)aCgOg. K by PtCl,, |
ppt. 145. White ppt. Na by flame.
i NH, in original
' solution.
| See also p 250, and the
| more delicate separation
given on p. 128,
?
=
a
x
&
:
a
=
Ss
>
TABLE OF SHORT DIRECTIONS FOR THE ANALYSIS OF AN AQUEOUS OR ONLY SLIGHTLY ACID SOLU-
TION OF ORDINARY SALTS OF ONE OF THE COMMON AND RARER METALS HITHERTO CONSIDERED.
Add hydrochloric acid.
—— = + wy
Precipitate If HCl gave no precipitate the metal is still in the liquid; pass H,S through the solution. |
Hg(ous) Pb Ag
Collect, wash, and add
He Pets eal ahi Cd Cu He(ic Pb Bi As
-y St 8. | Sb Sn Au Pt. ">, Seo
Ag ppt., dissolved. Collect wash, add NH,SH. | >» If NH,SH gave no precipitate,
pera Bi may alo} Insoluble Soluble. | 7, MeGa Ni Al add (NH,),CO,.
it A sera ge oF y | Cd, yellow. | As(ous & ic) Fe Cr ———~ > 1H (NE)O0, gave no
, but are dis Precipitate : ip a 1, Me sot
NH,OH., ae If H,S gave no precipitate add NH,Cl, NH,OH, and NH,SH,
yellow
ed on adding more | preci
HCl. : } Collect, wash, die- OH) HAS, |
solve in HC,H,0,, | If no precip- |
add K,Cr0,. Pot. ‘jitate, test orig. |
Me inal solution in
black.
| Apply special tests for each Ppt. :
| tee celatnal aotasion. or Bee |) Eee
these, see the previous pages, alk H,SO,. :
Sol.
246 THE METALLIC RADICALS,
The author cannot too strongly recommend students thoroughly
to master the art of analysis, not only on account of its direct
value, but because its practice enables them rapidly and soundly
‘to acquire a good knowledge of Chemistry, and greatly improve
their general mental faculties,
GENERAL AND SPECIAL MEMORANDA RELATING TO THE
PRECEDING ANALYTICAL TABLES,
General Memoranda.
These Tables are constructed for the analysis of salts more or
leas soluble in water.—The student has still to learn how sub-
stances insoluble in water are to be brought into a state of solu-
tion; but once dissolved, their analysis is effected by the same
scheme as that just given. The Tables, especially the longer
folded one, may therefore be regarded as fairly representing the
method by which metallic constituents of chemical substances are
separated from each other and recognized,
The group-reagents adopted in the Tables are hydrochloric acid,
hydrogen sulphide, ammonium hydrosulphide, ammonium carbonate
and ammonium phosphate, Ifa group-reagent produces no precipi-
tate, it is evident that there can be no member of the group
present. At first, therefore, add only a small quantity of a group-
reagent, and if it produces no effect add no more; for it is not
advisable to overload a solution with useless reagents ; substances
expected to come down as precipitates are not infrequently held
in solution in the liquid by excess of acid, alkali, or concentrated
aqueous solution of some group-reagent, thoughtlessly added.
Indeed, experienced manipulators make preliminary trials with
group-reagents on a few drops only of the liquid under exami-
nation ; if a precipitate is produced, it is added to the bulk of the
original liquid, and the addition of the group-reagent is continued;
if a precipitate is not produced, the few drops are thrown away;
and the unnecessary addition of a group-reagent thus avoided alto-
gether, an advantage fully making up for the extra trouble of
making a preliminary trial.—While shunning excess, however,
care must be taken to avoid deficiency; a substance only partially
removed from solution through the addition of an insufficient
amount of a reagent will appear where not expected, be constantly
mistaken for something else, and cause much trouble. Itis a good
plan, when a group-reagent has produced a precipitate and the
latter has heen filtered off, to add a little more of the reagent to
the clear filtrate; if more precipitate is produced, an insufficient
amount of the group-reagent was introduced in the first instance ;
but the error is corrected by simply refiltering ; if no precipitate
oceurs, the mind is satisfied and the way cleared for further opera-
tions,
QUALITATIVE ANALYSIS. 247
Group-precipitates, or any precipitates still requiring examin-
ation, should, as a rule, be well washed before further testing;
this is to remove the aqueous solution of other substances adhering
to the precipitate, so that subsequent reactions may take place
between the reagents used and the precipitate only.—A_precipi-
tate is sometimes in so fine a state of division as to retard filtration
by clogging the pores of the paper, or even to pass through the
filter altogether ; in these cases the mixture may be warmed or
boiled (or a fresh quantity of the original solution may be warmed
before the group-reagent is added), which usually causes aggrega-
tion of the particles of a precipitate, and hence facilitates the pas-
sage of liquids.
Division of work.—It is immaterial whether a solution be first
divided into group-precipitates or each precipitate be examined
as soon as produced; if the former method be adopted, confusion
will be avoided by labelling or marking the funnels or papers
holding the precipitate ‘‘the HCl ppt.,’’ ‘‘the H,S ppt.,’’ and so
on,
The colora and general appearance of the various sulphides and
hydroxides precipitated should be borne in mind, as the absence
of other substances, as well as the presence of those precipitated,
is often at once thus indicated.
Appt ication of confirmatory tests must be frequent.
. of analyses should be recorded neatly in a memorandum
book; a, for correction and endorsement by the teacher; 4, for
future reference by the student or by those who may need evidence
reapecting his labors; and, ¢, to promote mental orderliness,
various reactions which occurs in an analysis have already
come before the reader in going through the tests for the individ-
ual metals or in other analytical operations; it is unnecessary,
therefore, again to construct equations or diagrams. But the
reactions should be thought over, and if not perfectly clear to the
mind, be written out again and again, till thoroughly understood,
Special Memoranda.
The Hydrochloric-acid precipitate may at first include some anti-
mony and bismuth as oxychlorides, readily dissolved, however,
by excess of acid.—If cither of these elements be present, the
apy aie the precipitate will probably be milky; in that case
add a few drops of hydrochloric acid, which will clear the liquid
and make way for the application of the test for lead. —The
silver chloride and mercurous chloride precipitate should not be
long in contact with the ammonia, or silver will be reprecipitated
ed
'
2AgC) + 2HgCl + 4NH, = NHg,Cl, NH,Cl + 2NH,Cl+ 2Ag_
248 THE METALLIC RADICALS.
The hydrogen sulphide precipitate may be whitish, in which case
it is nothing but sulphur; for, as already indicated, ferric salts
are reduced by hydrogen sulphide to ferrous, and chromates to
chromic salts, finely divided whitish sulphur being deposited:—
4FeCl, + 2H,S = 4FeCl, + 4HCl + 8, ;
4CrO, + 2HS + 12HCl = 4CrCl, + 12H,0 + 88,
But the precipitate may also be very slightly yellow, or even
white when only a mercuric salt is present, through an insuffi-
ciency of hydrogen sulphide having produced a chlorosulphide.
The gas should be passed through the liquid until, even after well
shaking, the latter smells strongly of hydrogen sulphide.
The portion of the hydrogen sulphide precipitate dissolved by
ammonium hydrosulphide may include a trace of copper, cuprie
sulphide being not altogether insoluble in ammonium hydrosul-
phide.—On adding hydrochloric acid to the ammonium hydro-
sulphide solution, whitish or yellowish sulphur only may be pre-
cipitated, yellow ammonium hydrosulphide always containing free
sulphur.—Concentrated hydrochloric acid does not readily dis-
solve small quantities of antimonious sulphide out of much
arsenous sulphide; and, on the other hand, the concentrated
hydrochloric acid takes into solution a small quantity of arsenous
sulphide if much antimonious sulphide be present. The precipi-
tates or the orginal solutions should therefore be examined by the
other (hydrogen) tests for these elements if doubt exists concern-
ing the presence or absence of either. Tin remains in the hydro-
gen-bottle in the metallic state, deposited asa black powder on
the zinc used in the experiment. The contents of the bottle are
turned out into a dish, ebullition continued until] evolution of
hydrogen ceases, and the zinc is taken up by the excess of sul-
phurie acid employed; any tin is then filtered out, washed, dis-
solved in a few drops of hydrochloric acid, and the liquid tested
for tin by the usual reagents,—Tin may be detected in the
mixed tin, arsenic, and antimony sulphides by the blowpipe
reaction (p. 195).
The portion of the hydrogen sulphide precipitate not dissolved by
ammonium hydrosulphide may leave a yellow semi-fased globule
of sulphur on boiling with nitric acid. This globule may be black,
not only from presence of mercuric sulphide, but also from
enclosed particles of other sulphides protected by the sulphur from
the action of the acid. It may also contain lead sulphate, pro-
duced by the action of nitric acid on lead sulphide. In cases of
doubt the mass must be removed from the liquid, boiled with nitric
acid till dissolved, the solution evaporated to remove excess of
acid, and the residue examined; but usually it may he diare-
garded,—Before testing for bismuth, any considerable excess of
QUALITATIVE ANALYSIS. 249
acid should be removed by evaporation, and the residual liquid
should be freely diluted. If no precipitate (bismuth oxynitrate)
ap r, ammonium chloride solution may be added, bismuth oxy-
oride more readily forming than even oxynitrate, Or, any
nitric acid or sulphuric acid having been neutralized by adding
ammonia, hydrochloric acid is added and then potassium iodide ;
a rich orange color results if bismuth be present.—Bismuth may
also be detected in the mixed precipitated bismuth and lead hydrox-
ides, obtained in the ordinary course of analysis, by dissolving a
wee of the precipitate in acetic acid, adding the liquid to the
solution of lead iodide mentioned in 'the reactions for bismuth
231).—In testing for lead by means of sulphuric acid, the
aid should be diluted and set aside for some time.
phe pre may also be isolated by digesting the hydrogen sul-
hide preci wae in sodium hydrosulphide, instead of ammonium
hydro de. The arsenic, antimony, tin, and mercury sul-
ides are thus dissolved out. The mixture is then filtered, excess
of hydrochloric acid added to the filtrate, and the precipitated
ml hides collected on a filter, washed, and digested in ammonium
rosulphide ; mercury sulphide remains insoluble, while the
sri antimony, and tin sulphides are dissolved. By this
method copper also appears in its right place only, cupric sul-
phide being insoluble in sodium hydrosulphide. The other metals
are then separated in the usual way.
The ammonium hydrosulphide precipitate may, if the original
solution was acid, contain barium-group and magnesium phos-
phates, oxalates, silicates, and borates, These will subsequently
come out with the iron, and, being white, give the iron precipi-
tate a light-colored appearance ; their examination must be con-
ducted separately, by a method described subsequently in connec-
tion with the treatment of substances insoluble in water,—The
precipitate containing aluminium, iron, and chromium hydroxides
often contains some manganese. This manganese may be detected
by washing the hydroxides to remove all trace of chlorides, boil-
ing with nitric acid, adding either lead peroxide or red lead, and
setting the yessel aside; if manganese be present,.a red or purple
liquid is produced, —Nickel sulphide is not easily removed by
filtration (see p. 148) until most of the excess of ammonium hydro-
has been dissipated by prolonged ebullition.
ammonium carbonate precipitate may not contain the whole
of the barium, strontium and calcium in the mixture, unless free
ammonia be present; for the carbonates of these metals are solu-
ble in water shared with carbonic acid, If, therefore, the liquid
is not distinctly ammoniacal, ammonia water should be added.
—Neither ammonium carbonate nor ammonia wholly pree ipitates
magnesium salts; and as partial precipitation is undesirable,
amumen tun chloride, if not already present in the liquid, should.
be added,—In the Table opposite p. 245, it is directed that stron-
250 THE METALLIC RADICALS.
tium be separated from calcium by adding dilute sulphuric acid
to the acetic acid solution. This reagent, unless extremely dilute,
may precipitate calcium. Any such loss of calcium is in itself of
little consequence, because enough calcium sulphate remains in
the filtrate to afford a calcium reaction when ammonia water
andammonium oxalate are subsequently added. But the calcium
sulphate precipitated by the sulphuric acid may be wrongly set
down as strontium sulphate. Therefore test a little of the acetic
acid solution for strontium by adding an aqueous solution of cal-
cium sulphate, when, if no precipitate falls after setting aside for
several minutes, strontium may be regarded as absent, If a pre-
cipitate occurs, strontium is present: the rest of the acetic acid
solution is then tested for calcium as directed in the Table, the
final testing by means of ammonium oxalate being, of course, pre-
ceded by the addition of ammonia water. Barium may be over-
looked if oxidation happens to have converted any sulphur into
sulphuric acid,
Lithium.—Should a precipitate, supposed to be due to lithium,
be obtained, it must be tested in the Bunsen flame, If the
characteristic crimson flame coloration is not observable, the pre-
cipitate is probably due to a small quantity of magnesium, which
not infrequently shows itself under the conditions requisite for
the precipitation of lithium. If present only in minute propor-
tions, the lithium may also remain with the alkali-metals; it can
then be detected by means of the spectroscope. Such a method
of examination is called spectrum analysis, a subject of much
interest and of no great difficulty ; it will be described briefly in
connection with the methods of analyzing solid substances,
QUESTIONS AND EXERCISES.
Describe a general method of analysis by which the metal of a single
salt in a solution could be quickly detected, —Give illustrations of black,
white, buff, yellow and orange sulphides.—Mention the group-reagents
usually employed in analysis—Under what circumstances may a hydro-
chloric acid precipitate contain antimony or bismuth ?—If a hydrogen
sulphide precipitate is white, what substances are indicated ?—Give
processes for the qualitative analysis of liquids containing the following
substunces:—a, Arsenic and Cadmium. >. Bismoth and Antimony.
ce, Antimony and Mercurous salt. d. Silveranud Mercurous salts. e. Fer-
rous and Ferric salt. f. Aluminium, Iren, and Chromium, g. Arsenic,
Antimony, and Tin. A. Leadand Strontiom. i, Lead and Mercurie salt.
j, Copper and Arsenic, & Aluminium and Zine. /. Iron and Copper.
m. Tron, Sodium, and Arsenic, w». Mercury, Manganese, and Maguesium.
o, Zine, Manganese, Nickel, and Cobalt. p. Barium, Strontiom, and
(alcium, g. Zinc, Magnesium, and Ammonium. r. Alaominium und
Magnesiom, »#. lron, Barium, and Potassiam. ¢. Magnesium, Caleium,
and Potassium. wu. Silver, Antimony, Zinc, Barium, and Ammonium.
THE ACID RADICALS,
THE ACID RADICALS.
With the exception of ammonium, NH,, the twenty-seven radi-
cals which have up to this point mainly occupied attention, are
metals. They have been studied for the most part, not in the
free or uncombined state, but in the condition in which they exist
in salts, i, €., as the metallic radicals of salts, As already men-
tioned (nee p. 65), salts may be regarded as composed of a metallic
radical united with an acid radical. Every acid, too, may be
regarded as consisting of hydrogen, which plays ‘the part of a
metallic radical, united with an acid radical; and hence the acids
are sometimes called hydrogen salts. When the place of this
hydrogen in an acid is taken by a metal, the product is simply
called a salt. In this section of the Manual, we shall take up the
study of a number of important salts from the point of view of
the acid radicals. which they contain and, incidentally, we shall
also study the acids, in which these radicals occur in combination
with hydrogen.
Juat as there are univalent, bivalent, etc., metallic radicals, 80
there are univalent, bivalent, etc., acid radicals, The acids cor-
responding to these radicals contain one, two, etc., atoms of
displaceable hydrogen, and on this ace ount are called monobasic,
(libasic, ete., acids: thus, hydrochloric acid, HCI, is monobasic ;
<ulphuric acid, H,S0,, is dibasic; orthophosphoric acid, H,PO,,
is tribasic. Acids of higher basicity are also known.
The stadent should note carefully the signification of the words
srong and weak as applied to acids, and must not confuse the
ideas implied by these terms with thore conv eyed respectively by
the description of acids as concenfrated and dilute (not necessarily
*‘diluted,”’ i. ¢., prepared by dilution), A strong acid is one
which exhibits the characters of an acid in a well-marked manne r,
while a weak acid only possesses these characters to a limited
extent. Considered in this respect, sulphuric acid is a strong
acid, while acetic acid is a weak one. The sfate of concentration
of an acid is often described as its ‘* strength,’’ but this usage is
not to be commended, the single word ‘‘ concentration ’’ being the
term which is now usually employed in chemistry to designate
this degree of concentration or ‘‘state of concentration.” Sul-
phurie acid, even when dilute, is stil] a strong acid, while acetic
acid, even when highly concentrated, is still a comparatively
weak acid, With regard to two samples of dilute acid, the one
of which contains, say, fifteen, and the other twenty percent. of
sul phuric acid, it would be correct to sy that the concentration of
the, latter is greater than that of the former; i. ¢., that im any
THE ACID RADICALS,
given volume of the latter solution there is more sulphuric acid
than in the same volume of the former solution,
HYDROCHLORIC ACID, HCl, AND OTHER CHLORIDES.
The acid radical of hydrochloric acid and of other chlorides is
chlorine, Cl. Chlorine occurs in nature chiefly as sodium chloride,
NaCl. Sodium chloride is a very abundant substance, occurring
either solid as rock-salf, deposits of which exist in Cheshire, at
Stassturt, and elsewhere, or in solution in the water of all seas,
Common table-salt is more or less pure sodium chloride in minute
crystals. Chlorine, in hydrochloric acid and the chlorides, is
univalent (Cl’); its atomic weight is 35.18, The molecular
formula for chlorine isCl,. Hydrochloric acid is a monobasic acid,
HYDROCHLORIC ACID.
Experiment 1.—To a few fragments of sodium chloride in
a test-tube or small flask, add about an equal- weight of sul-
phuric acid ; colorless hydrochloric acid gas is evolved, and
Fig. 37.
Preparation of hydrochloric acid.
sodium hydrogen sulphate remains, Adapt to the mouth of
the vessel, by means of a perforated cork, a piece of glass
tubing bent to a right angle; heat the mixture ( Fig. 10, p, 34,
or Fig. 37, above) and convey the gas into a little water;
solution of hydrochloric acid results.
NaCl + HO, HCl + NaHso,
Sodium Sulphuric Hydrochloric Sodium hydrogen
chloride aeld acid sulphate
CHLORIDES. 253
The product of this operation is the nearly colorless and very
sour liquid commonly termed hydrochloric acid. When of certain
“‘eoncentrations*’ (determined by volumetric analysis), it forms
Acidum Hydrochloricum, U. 8. P., <Acidum Hydrochloricum
Dilutum, U.S. P. The former has a specific gravity of 1.158,
and contains 31.9 percent. of real acid; the latter, specific
gravity 1.049, with 10 percent. of real acid, is made by diluting
100 parts by weight of the more concentrated acid with 219 parts
of water. The above process is that of the manufacturer—larger
vessels being employed, and the gas being freed from any trace
of sulphuric acid by washing. Other chlorides yield hydro-
chloric acid when heated with sylpburic acid; but sodium chloride
is always used because it is plentiful and therefore cheap.
Commercial hydrochloric acid is a by-product in the manufacture
of sodium carbonate from common salt (by the process in which
sodium chloride is first converted into sulphate, hydrochloric acid
being liberated and dissolved in water), The impure acid has a
yellow color and is liable to contain iron, arsenic, alkali-metal
salts, sulphuric acid and nitrous compounds; sometimes, also,
sulphurous acid or chlorine.
nvisible gaseous hydrochloric acid forms visible grayish-white
fumes on coming into contact withair. This is due to its abstract-
ing moisture from the air and disso] ving in it, the fumes consisting
of minute particles of solution of hydrochloric acid. The great
readiness with which hydrochloric acid gas dissolves in water is
strikingly demonstrated on opening a test-tube full of the gas
under water; the latter rushes into and instantly fills the tube,
If the water is tinged with blue litmus, the acid character of the
gus is 'y shown at the same time. The test-tube, which
should be perfectly dry, may be filled from the delivery-tube
direct; for the gas is somewhat heavier than air and therefore
readily displaces it. At low temperatures hydrochloric acid and
water form a crystalline compound, HCl, 2H,0.
Note.—The process, as described (p. 252), includes the use of
as much sulphuric acid as is necessary for the production of the
acid sodium sulphate, NaHSO,, which remains in the generating
vessel. A hot solution of this residue, neutralized by sodium
carbonate, filtered and set aside, yields normal sodium sulphate
ay Sulphas, U. 8. P.), Glauber’s Salt, Na,SO,,10H,O, in the
of transparent, oblique, efflorescent prisms.
2NaHSO, + Na CO, = 2Na,80, + H,O 4. co,
Sodium hydrogen Sodium Sodium Water Carbonic
sulphate carbonate sulphate anhydride
In the commercial preparation of sodium sulphate for the
manufacture of sodium carbonate by the Leblanc process, the
254 THE ACID RADICALS,
proportions in which the sodium chloride and the sulphuric acid
are employed are those required to form normal sodium sulphate
and not acid sodium sulphate, To carry out this reaction a higher
temperature is necessary, 2NaCl+ H,SO,—2HCI1+ NaSo,.
CHLORINE.
Experiment 2.—To some drops of hydrochloric acid (that
is, the common aqueous solution of the gas) add a few grains
of black manganese oxide, and warm the mixture; chloride is
evolved, and may be recognized by its peculiar odor and by
its highly irritating effect on the nose and air-passages.
4HCl + MnO, = Cl, + 2H,O + MnCl,
Chlorine water.—Liquor Chlori Compositus, the chlorine water
of the U.S. P. is prepared by dissolving in water the gas produced
by acting on potassium chlorate with hydrochloric acid diluted
with its own weight of water. It contains some oxides of chlorine
and potassium chloride, At ordinary temperatures, if fresh and
thoroughly saturated, chlorine water contains about 0.4 percent,
of chlorine. When chlorine water is exposed to daylight, the
chlorine slowly decomposes water with production of hydrochloric
acid and oxygen; hence the solution should be freshly prepared;
it is best preserved in a green glass well-stoppered bottle in a cool
and dark place. Chlorine passed into cold water yields crystals
of chlorine hydrate, C],8H,O, and these, when heated in a sealed
tube under pressure, give an upper layer of chlorine water and a
lower layer of fiquid chlorine.
Note.—To obtain the chlorine from other chlorides, such as
sodium chloride, sulphuric acid, as well as black manganese oxide,
must be added, It may be assumed that hydrochloric acid ts first
formed by the action of sulphuric acid on the sodium chloride,
und that this then interacts with black manganese oxide and
more sulphuric acid to form chlorine, manganous sulphate, and
water. The following equations may represent these steps in the
Process :—
2NaCl + H,SO, = Na,SO, + 2HCI,
MnO, + 2HC! 4+ H,SO, = Cl, 4+- MnSO, + 2H,0;
or the whole may be included in one equation :
2NaCl + MnO, + 2H,SO, = NaSO, + MnsSO, + 2H,0 4 Cl,
CHLORIDES. 255
This reaction may occasionally have analytical interest, a very
small quantity of chloride being recognizable by its means. But
the following reaction is nearly always applicable for the detec-
tion of this element, and leaves little to be desired in point of deli-
cacy :—
Analytical Reactions of Chlorides.
To a drop of hydrochlorie acid, or to a dilute solution of any
other chloride, add solution of silver nitrate ; a white curdy precip-
itate of silver chloride, AgCl, is produced, Pour away the super-
natant liquid, add nitric acid, and boil ; the precipitate does not
dissolve. Pour away the acid, and add dilute ammonia water;
the precipitate quickly dissolves. Neutralize the solution by
adding an acid ; the curdy precipitate again appears.
The formation of this white precipitate, its appearance, insolu-
bility in boiling nitric acid, solubility in ammonia water and repre-
cipitation by an acid, form, in the known absence of bromide, abun-
dant evidence of the presence of chloride.
If free hydrochloric acid be present in a quantity in a solution,
it will, in addition to the reaction with silver nitrate, give rise to
strong effervescence on the addition of a carbonate, a chloride
being formed. The chlorine in insoluble chlorides, such as calo-
mel, white precipitate, etc., may be detected by boiling with caus-
tic alkali, filtering, acidulating the filtrate by means of nitric acid,
and then adding the silver nitrate.
Antidotes,—In cases of poisoning by hydrochloric acid, solution
of sodium carbonate (common washing-soda) or a mixture of
magnesia and water may be administered.
QUESTIONS AND EXERCISES.
Whiy does hydrochloric acid gas give visible fumes on coming into con-
tact with air?’—How much sodium chloride will be required to furnish
one pound of chlorine ?—Give the analytical reactions of chlorides.—What
antidotes may be administered in cases of poisoning by hydrochloric acid ?
HYDROBROMIC ACID, HBr, AND OTHER BROMIDES.
Bromine :—Source, Preparation and I ‘roperties. —The acid rad ical
of hydrobromic acid and other bromides is bromine, Br (Bromum,
U.S P.). Bromine occurs in nature in the form of bromides in
sea-water and certain saline eprings, and is prepared from the /it-
tern, or residual liquors of salt works. It may be liberated from
256 THE ACID RADICALS.
bromides by a process similar to that employed for liberating
chlorine from chlorides—that is, by heating with black manganese
oxide and sulphuric acid (see note on p, 254); but is now largely
obtained by liberating it from bromides by the action of chlorine.
(Compare reaction, p. 257). It is dark-red volatile liquid of
specific gravity, 2.99 to 3,0 at 15°C, and possessing an odor more
irritating, if possible, than that of chlorine.—Its boiling point is
63°C, (145.4° F.). Bromine in hydrobromie acid and the brom-
ides, is univalent (Br’). Its atomic weight is 79.36, and its mole-
cular formula is Br,
Hydrobromic acid. —Hydrogen bromide, or hydrobromic acid,
may be made by Gecompiping phosphorous tri-bromide or penta-
bromide by means of water; PBr,4-3H,O= SHBr+H ,PO,, or
PBr,+-4H,O=5HBr+ H,PO,. A small quantity is prepared by
placing seven or eight drops
Fia. 38. of bromine at the bottom of
a test-tube, putting in frag-
ments of glass to the height
of about an inch or two, then
ten or eleven grains of red
phosphorus, then another
inch of glass, and finally a
couple of inches of glass
fragments slightly wet with
water, a delivery-tube being
= fitted by means of a cork,
Preparation of hydrobromie acid, The phosphorus combines
readily, almost violently,
with the bromine as soon as the vapor of the latter, aided by gentle
heating, comes imto contact with the phosphorus, The phos-
phorus tri-bromide — formed then suffers by decomposition by
the water of the moist glass, hydrobromic and phosphorous acids
being produced. The hydrobromic acid gas passes over (further
heat being applied in the later stages of the operation) and may
be led into water or ammonia water. The latter solution on evapo-
ration yields ammonium bromide,
Solution of hydrobromic acid may also be prepared by passing
hydrogen sulphide through bromine covered with water, until all
color has disappeared, and then distilling the mixture. 10Br,+
4H,8+ 8H,O=20HBr+2H,S0,+8,. A better method is that of
Scott, who prepares pure solution of hydrobromic acid by passing
purified sulphurous anhydride into water lying over a layer o
bromine, until a homogeneous liquid, still slightly yellow from the
presence of free bromine, is obtained; and then distilling this
liquid several times, so as to remove uncombined bromine and
traces of sulphuric acid, Br,-+-SO,4+-2H,O=2HBr+H 80, For
rapidly obtaining a solution of hydrobromic acid on a small seale,
H. Marshall recommends the addition of sulphuric acid to a
BROMIDES. 257
saturated solution of barium bromide, in a quantity nearly but not
cr sufficient to precipitate the whole of the barium as sulphate,
ollowed by filtration of the solution, and distillation.
Hydrobromic acid, like hydrochloric acid, is monobasic.
Acidum Hydrobromicum Dilutum, U. 8, P., is prepared by the
distillation of potassium bromide with concentrated phosphoric
acid. Its specific gravity is 1.076, and it contains 10 percent. by
weight of hydrogen bromide, HBr,
Potassium Bromide, KBr, is very largely employed in pharmacy,
and may be used in studying the reactions of bromides. The
method of making the salt has been alluded to under the potas-
sium salts (p. 81).
Sodium Bromide crystallizes in anhydrous cubes, NaBr from
solutions at 110° to 120° F. (48.3°-48.8° C.), and in hydrous
prisms, NaBr, 2H,O, at ordinary temperatures,
Ammonium Bromide, NH,Br (Ammonii Bromidum, U. 5. P.)
may be made by neutralizing hydrobromic acid with ammonia :
HBr+NH,OH=NH,Br+H,0. It forms colorless crystals which
may become slightly yellow on exposure to air. It is readily
soluble in water, less so in alcohol, and sublimes when heated.
Other bromides are seldom used ; they may be prepared in the
way as the corresponding chlorides or iodides, which they closely
resemble,
Bromine Teat Solution, U. 5. P., (Bromine Water) 1 part in 100,
is an aqueous solution, bromine being slightly soluble in water,
Hypobromites and 'Bromates, analogous to hypochlorites and
chlorates, can easily be prepared.
Bromates, occurring as impurity in bromides, are detected by
dropping dilute sulphuric acid upon the salt; a yellow color,
due to free bromine, is produced immediately if bromates are
present :—
KBr + H,SO, HBr -+ KHSO,
KBrO, + H.SO, = HBrO, + KHSO,
SHBr + HBrO,= 3Br, + 3H,0
Analytical Reactions of Bromides.
1. To a few drops of a solution of a bromide (KBr or
NH, Br) add solution of silver nitrate; a yellowish-white pre-
cipitate of silver bromide, AgBr, is produced. Treat the precipi-
tate successively with nitric acid and dilute ammonia water,
as described under silyer chloride; it is dissolyed by the
ammonia solution, hut somewhat less readily than the silver
chloride.
2. To a solution of a bromide add a few drops of chlorine
water, or pass in some bubbles of chlorine gas ; then add a
17
258 THE ACID RADICALS.
few drops of chloroform, or ether, or carbon disulphide, shake
the mixture, and set the test-tube aside ; the chlorine displaces
the bromine, which is dissolyed by the chloroform, ether, or
carbon disulphide (the solution falling to the bottom of the
tube in the case of the heavy chloroform or carbon sulphide,
or rising to the top in the case of the light ether). The solu-
tion of bromine has a distinct yellow, or reddish-yellow, or red
color, according to the amount of bromine present in it,
2K Br + Cl, = 2KCl + Br,
Note, —This reaction serves for the isolation of bromine when
mixed with many other substances. Excess of chlorine must be
avoided, as colorless bromine chlorine is then formed, Iodides
give a somewhat similar appearance; the absence of iodine must
therefore be ensured by a process given in the next section, The
above solution in chloroform or ether may be removed from the
tube by drawing it up into a pipette (small pipe—a narrow glass-
tube, usually having a bulb or expanded portion in the renin
the bromine which it contains may be converted into relatively
non-volatile salts by the addition of a drop of solution of potassium
or sodium hydroxide ; the chloroform or ether may then be removed
by evaporation, and the residue tested as described in the next
paragraph,
3. Liberate bromine from a bromide by the cautious addi-
tion of chlorine or chlorine water, then add a few drops of
cold mucilage of starch ; a yellow combination of bromine and
.3
starch, termed “starch bromide,” is formed.
Bromine may also be liberated from bromides by adding concen-
trated sulphuric acid and some black manganese oxide, and gently
heating. Even sulphuric acid alone, if concentrated, liberates
bromine from a bromide, the hydrogen of the hydrobromie acid
combining to some extent with the oxygen of the sulphuric acid,
and the latter being reduced to sulphurous anhydride :—
2KBr + 2H,80, = K,SO, + Br, + 80, + 2H,0
HYDRIODIC ACID, HI, AND OTHER IODIDES.
lodine :—Source.—The acid radicals of hydriodic acid and other
iodides is iodine, J. Iodine occurs in nature in the form of iodides,
in sea-water, Sea-weeds, sponges, and other marine organisms,
which derive much of their nourishment from sea-water, store up
iodides in their tissues ; and it is from the ashes of these that sup-
plies of iodine (Jodum, U. 8, P.)\, are obtained. Toedine also
occurs in the form of iodates in crude sodium nitrate,
LIODIDES, 259
Preparation,—The sea-weed ash, or e/p, is treated with water,
insoluble matter thrown away, and the decanted liquid evaporated
and set aside to allow of the deposition of most of the sodium and
potassium sulphates, carbonates, and chlorides. The residual
liquor is treated with excess of sulphuric acid, which causes evolu-
tion of carbonic anhydride and of sulphurous anhydride or hydro-
gen sulphide, deposition of sulphur and more sodium sulphate, and
formation of hydriodie acid. To the decanted liquid black man-
ganese oxide is added, and the mixture is then slowly distilled;
the iodine sublimes and is afterwards purified by resublimation.
2HI + MnO, + H,SO, = MnSO, + 2H,0+1,
Properties.—lodine is a crystalline purplish-black solid; its
vapor, readily seen on heating a fragment in a test-tube, is dark
violet. The vapor is irritating to the lungs ; but a trace may be
inhaled with safety. lodine melts at 237,2° F. (114° C.), boils at
about 392° F. (200° C.), the first portions containing any cyanogen
iodide that may be present. The latter substance, which is rarely
present in iodine, forms slender, colorless prisms, which emit a pun-
gent odor,
Solution of Jodine.—Iodine is slightly soluble in water (iodine-
water), and readily soluble in an aqueous solution of potassium
iodide. Five parts of iodine and ten of potassium iodide, dis-
solved in sufficient distilled water to make 100 parts, form Liquor
Todi Compositus, U.S. P. Tinectura Jodi, U. 8. P. is an alcoholic
preparation of different strength, 4 parts of iodine and 4 of potas-
sium jodide, rubbed with 12 of glycerin, and 80 of benzoinated
lard, form Unguentum Jodi, U.8. P.
Todine combines with sulphur, forming an .unstable grayish-
black, solid iodide, S8,1,, having a radiated crystalline structure
(Sulphuris Iodidum, U. 5. P.).
Todine in hydriodic acid and the iodides, is univalent (I’). The
' Todine forms differently colored solutions with different solvents: eg.
the solution in water, alcohol, ether, or aqueous solution of potassium
jodide is brown, while the solution in chloroform, benzene, or carbon
diaulphide, is violet. 2? ee ee
260 THE ACID RADICALS.
a mixture of one part of red phosphorus with two of water.
Abundance of hydriodic acid is evolved on the gentle application
of heat, and dissolves in the water in the receiver. Phosphoric
acid remains.—P, + 101, 4+ 16H,O = 20HI + 4H,PO,. See
analogous reaction for HBr, p. 256.
The official acid (Acidum Hydriodicum Dilutum) is prepared by
the action of tartaric acid, in dilute alcoholic solation, on potas-
sium iodide in presence of a small quantity of potassium hypo-
phosphite, the alcohol being subsequently removed. The function
of the hypophosphite is to prevent the liberation of iodine through
oxidation of part of the hydriodic acid,
Syrupus Acidi Hydriodici, U.S. P., contains about 1 percent.
of hydrogen iodide.
Potassium Iodide, KI, is largely used in medicine, and is a con-
04 salt on which to experiment in studying the reactions of
iodides,
Nitrogen Iodide is formed when excess of aqueous ammonia is
added to a solution of iodine in potassium iodide,
Analytical Reactions of Iodides.
1. To a few drops of an aqueous solution of an iodide (e.g.
KI) add solution of silver nitrate; a pale yellow precipitate
of silver iodide, AgI, is produced. Pour away the supernatant
liquid, and treat the precipitate with nitric acid; it 1s not dis-
solved. Pour away the acid, and then add ammonia water;
the precipitate is almost unchanged. —
2. Liberate iodine from an iodide by the cautious addition
of chlorine water, then add starch mucilage; a deep-blue com-
bination of iodine and starch, termed “starch iodide,” is formed.
This reaction is very delicate and characteristic. Heat decom-
poses the blue compound, Excess of chlorine must be avoided, or a
solution of iodic acid will be produced, which is colorless, Nitrous
acid, or a nitrite acidulated with sulphuric acid, may be used instead
of chlorine. Concentrated sulphuric acid also liberates iodine
from iodides, the hydrogen of the hydriodic acid first produced
uniting with the oxygen of the sulphuric acid whereby the latter
is reduced to sulphurous anhydride, or even to hydrogen sul-
phide.
In testing bromine for the presence of iodine, the bromine must
be nearly all converted into hydrobromic acid by means of dilute
solution of sulphurous acid (see p, 256, Scott's process) or be nearly
removed by addition of sodium hydroxide, before the starch of
mucilage is added. i
Ozone (O,), —Papers soaked in starch mucilage containing potas-
sium iodide form a teat for free chlorine and nitrous acid, and are
IODIDES. 261
also employed by meteorologists to detect an allotropic and eid
active form of oxygen, termed by Schénbein ozone (from bfw, o2d,
I smell), which also liberates iodine from potassium iodide with
formation of starch iodide. Ozone is supposed to occur normally
in the atmosphere, the salubrity or insalubrity of which is said to
be t to some extent on its presence or absence. The
possible occurrence in the air of nitrous or other oxidizing gases
(as well as ozone) renders the starch test untrustworthy. Houzeau
proposed to test for ozone by exposing litmus-paper of a neutral
tint soaked in a dilute solution of potassium iodide; the alkali set
free by the action of the ozone turns the paper blue. The same
paper without iodide would indicate the extent to which the effect
might be due toammonia. Ozone, or rather, ozonized air, is pro-
duced artificially in large quantities by passing air through a box
(Beane’s Ozone generator) in which it is exposed to the silent
electrical discharge. In the latter operation condensation of the
volume of air, or rather, of the oxygen in the air, occurs. Ozone
is also produced in small quantity when phosphorus undergoes
slow oxidation in moist air, some hydrogen peroxide and ammo-
nium nitrate being formed at the same time. Ozone is a powerful
bleaching, disinfecting and oxidizing agent; it is very sparingly
soluble in water, but soluble in oils of turpentine and cinnamon,
and in some other liquids, Its odor is chareteristic, From experi-
ments that have been made by Soret on the specifie gravity of
ozone, its molecular formula seems to be O,, that of ordinary oxy-
gen being O,.
3, To a neutral aqueous solution of an iodide add a solu-
tion containing one part of cupric sulphate and two and a half
parts of ferrous sulphate, and well shake ; a dirty-white pre-
cipitate of cuprous iodide, Cul, is prod uced.
2KI + 2CuSO, + 2FeSO, = 2Cul + K.SO, + Fe,(SO,),
Or to the liquid containing an iodide add solution of cupric
sulphate some solution of sulphurous acid, and warm the
mixture; cuprous iodide is again produced.
2KI + 2CuS0, + H,S0,+ H,O = 2Cul + 2KHSO,+ H,SO,
Separation of Chiorides, Bromides, and Todidea,—Chlorides and
bromides are Sis precipitated by curpric sulphate ; the above
reaction is useful, therefore, in removing iodine from a solution
in which chlorides and bromides may also be present. The total
removal of iodine by the former of the two modifications of the
ae is ensured by following up the addition of the curpric and
sulphates by adding a few drops of solution of potassium
or sodium ydiexite, any acid which might retain cuprous iodide
262 THE ACID RADICALS.
in solution being thereby neutralized ; ferric or ferrous hydroxide,
precipitated at the same time, not affecting the reaction, Occa-
sionally, too, it may be necessary to repeat the process with the
filtrate before the last traces of iodine are removed, The second
modification of the process is, on the whole, to be preferred.
Hart s Test. —(If nitrates, chlorates, bromates, or iodates are pres-
ent, it is necessary to fuse the substance with a little sodium car-
bonate and charcoal to reduce them. If the chlorine, bromine, and
iodine, are united with silver, it is best to fuse with sodium carbonate
and extract with water, although with iodine and bromine this is not
absolutely necessary.) The substance is placed in the flask shown
in the figure given in the section on the quantitative analysis of
manganese oxide (see Index), with some water and a few drops of
solution of ferric sulphate. Into the bulbs a few drops of dilute
starch mucilage are poured. The bulbs are kept cold by immer-
sing in water ina beaker. The contents of the flask are then
boiled, and if iodine is present the starch is colored blue, This
test is extremely delicate, If iodine is found, the cork and the
bulb tube are removed, and the solution boiled until, on testing
again in the same way, no more iodine is found. If much iodine
is present, it is necessary to add more ferric sulphate solution.
The bulb tube is now cleaned, charged with a few drops of water
and a drop or two of chloroform, and a very small crystal of
potassium permanganate is added to the solution in the flask.
The contents of the flask are boiled again, and if bromine is
present the chloroform becomes red. The tube is now removed,
and more potassium permanganate and ferric sulphate added little
by little, the mixture being boiled between each addition until
the bromine has all been driven off. A few drops of alcohol are
added to the contents of the flash to decolorize any excess of per-
manganate, and, after filtration, chlorine is tested for in the filtrate
by means of silver nitrate.
Detection of Chloride in presence of Bromide or Iodide or
both.—To a small quantity of the mixed solution add excess
of silver nitrate in presence of nitric acid, and wash the pre-
cipitate once or twice with water by decantation, Then pour
upon the precipitate 1 Ce. of a very dilute solution of potas
sium iodide (1 part in 1000 of water), add a few drops of
dilute nitric acid, allow to stand in the cold for an hour with
occasional shaking, and filter. Divide the Altrate into two
parts, and add silver nitrate to one part and a drop of diluted
chlorine water to the other. If the silver nitrate produces a
white precipitate ' and the chlorine does not liberate either
1 Silver nitrate produces a precipitate in any case, which may con-
sist of silver chloride, bromide, or iodide and may, therefore, be pure
white, yellowish, or yellow,
IODIDES. 263
bromine or iodine, then the original precipitate contained sil-
ver chloride.
The action of the potassium iodide on the silver chloride is repre-
sented by the equation :—AgCl + KI = Agl + KCl. If there is
enough silver chloride present in the original precipitate, all the
added potassium iodide is converted into potassium chloride and
it is the latter which gives the white precipitate on the addition
of silver nitrate. If the chlorine water liberates bromine or iodine,
this shows (when not more the | Ce. of the 1 in 1000 potassium
iodide has been used) that distinctly less than 1 milligramme of
silver chloride, and probably none at all, was present.
Chlorides may also be detected in presence of bromides and
iodides by taking advantage of the formation of chlorochromic
anhydride (p. 169) and the non-occurrence of corresponding com-
pounds of bromine or iodine, as follows:—
To a solution of a mixture of an iodide with a bromide and
a chloride add a concentrated solution of sodium sulphite, then
a reagent prepared by mixing equal volumes of sulphuric acid
and saturated solution of cupric sulphate, until no further pre-
cipitation of cuprous iodide occurs. Next add solution sodium
hydroxide to remove the excess of copper, filter, and evaporate
to dryness. ‘Transfer the dried residue, together with an equal
bulk of potassium dichromate, to a dry test-tube fitted with a
delivery-tube, or to a small retort, and cover the mixture with
sulphuric acid. Distil into water. Chromic anhydride and
hydrochloric and hydrobromic acids are liberated by the sul-
phurie acid, and interacting with one another, form chloro-
ehromic anhydride, together with free bromine abd chlorine.
GrO, + 2HCl = CrO,Cl,+ HO |
2CrO, -+- 6H Br + 3H,8O,— Cr,(SO,), + 3Br, + 6H,O
2CrO, + 6HCI + 3H,SO, = Cr,(SO,), + 3Cl, 4+ 6H,O
The chlorochromic anhydride is decomposed by the excess of
water into which it distils, giving rise to anhydrochromic acid,
Which imparts its orange color to the liquid, and hydrochloric
acid, thus: 2CrO,Cl, + 3H,0 = H,Cr,0, + 4HCI. The chlorine
which is produved in the reaction escapes, and the bromine is dis-
solved by water. The colored liquid is then shaken with chloro-
form, which removes the bromine, indicating bromides in the
riginal substance ; a yellow or orange color remaining is due to
anhydrochromic acid, indicating chlorides in the orginal substance,
Or ammonia may be added to the distillate; the color due to
bromine is thereby entirely removed, while the yellow color of
ammonium chromate remains. }
264 THE ACID RADICALS.
Instead of eliminating the iodine as cuprous iodide, it may be
expelled in vapor (obvious enough by its color and odor) by fusing
the dry mixture of the salts with excess of powdered potassium
dichromate. The residue, broken into small fragments, may then
be distilled with sulphuric acid for the detection of the bromine
and chlorine,
6K,Cr,0, + 6KI = 8K,CrO, + Cr,0, + 31,
4. Iodides have been shown to be useful in testing for mer-
curie salts (see the Mercury reactions, p. 218); a mercuric salt
(corrosive sublimate, for example) may therefore be used in
testing for iodides, a scarlet precipitate of mercuric iodide,
Hgl,, being produced.
This reaction may be employed where comparatively large
quantities of an iodide are present; but its usefulness in analysis
is limited by the fact that the precipitate is soluble in excess of
the dissolved iodide, or in excess of the mercuric solution, The
color of the precipitate and its insolubility in water distinguish it
from mercuric chloride, bromide, and cyanide, which are white
soluble salts.
5. Iodides have also been shown to be useful in testing for
lead salts (see the Lead reactions, p. 224); similarly a- lead
salt (acetate, for example) may be used in testing for iodides
in solutions which are either neutral or faintly acid with acetic
acid, a yellow precipitate of lead iodide, PbI,, soluble in hot
water and crystallizing in yellow scales on cooling, being
produced.
Lead chloride, bromide, and cyanide are white; hence the above
reaction may occasionally be useful in distinguishing iodides
from chlorides, bromides or cyanides. But lead iodide is slightly
soluble in cold water; hence small quantities of iodides cannot be
detected by means of this reaction. (For Iodates, see p, 280),
Analogies between Chlorine, Bromine, lodine and their Com-
pounds,—These elements form a natural group or family, the
members of which are closely related and exhibit a distinct gra-
dation in physical properties. Thus chlorine is a gas and iodine
a solid, while bromine occupies the intermediate liquid condition,
The atomic weight of bromine is nearly midway between those of
chlorine and iodine. The specific gravity of liquid chlorine i#
1,33, of iodine 4.95, while that of bromine is nearly 3. Liquid
chlorine is transparent, iodine opaque, bromine intermediate.
The crystalline forms of the chloride, bromide and iodide of the
same metal are commonly identical. One volume of either element
in the gaseous state combines with an equal volume of hydrogen
CYANIDES. ; 265
(at the same temperature and pressure) to form two volumes of a
gaseous acid, very soluble in water (hydrochloric acid, hydrobromic
acid, hydriedic acid). By their union with metals, chlorine,
bromine, and iodine form salts of which sodium chloride, bromide
and jodide may be taken as types. On this account they have been
called the halogens (i.e., salt producers), and the salts are called
haloid salts (from atc, hals, sea-salt, and eldoc, edios, likeness),
————$—
QUESTIONS AND EXERCISES,
State the method by which bromine is obtained from its natural com-
pounds.—Mention the properties of bromine.—How may potassium and
ammonium bromides be made ?—By what reagents may bromides be dis-
tinguished from chlorides?—Whence is iodine obtained (—By what pro-
cess isiodine isolated ?—State the properties of iodine.—What is the nature
of sulphur iodide ?—Give the analytical reactions of iodides—What three
sul
: may, indireetly, be detected by a mixture of potassium iodide
and starch — ?—Describe two methods by which iodides may be
removed from a solution containing chlorides and bromides,
HYDROCYANIC ACID, HCN, AND OTHER CYANIDES.
The acid radical of hydrocyanic acid and other cyanides is a
compound group, the cyanogen radical, CN, (or shortly, Cy). It
is 80 1 from xbavec, kuanos, blue, and yervaw, gennao, I gener-
ate, in allusion to its prominent chemical character for forming,
with certain iron compounds, the different varieties of Prussian
blue. It was from Prussian blue that Scheele, in 1782, first
obtained what we now, from our knowledge of its composition,
call hydrocyanic acid, HCN or HCy, also called prussic acid.
, OLN,, was isolated by Gay-Lussac in 1814, and was the
first compound radical distinctly proved to exist.
Sources, ete. —Certain compounds containing the cyanogen radi-
ex) oceur in nature, and others can easily be prepared. Ammo-
nium eyanide is found in small quantities among the gases of iron
furnaces, and is produced to a slight extent in distilling coal for
In the preparation of potasstum ferrocyanide the cyanogen
radical is formed abundantly by heating animal refuse containing
nitrogen, such asthe scrapings of horns, hoofs, and hides (5 parts),
with crude potassium carbonate (2 parts) and waste iron ( filings,
etc.) in a covered iron pot. The residual mass, which contains
potassium cyanide, but no ferrocyanide, is boiled with water, the
mixture filtered, and the filtrate evaporated and set aside for crys-
tals of ferrocyanide to form. The cyanogen, produced from the
carbon and nitrogen of the animal matter, unites with the potas-
266 ‘THE ACID RADICALS,
sium to form potassium cyanide and this afterward, on boiling
with water, interacts with iron sulphides (produced by the inter-
action of the iron with sulphur occurring in the nitrogenous
organic matters, and as sulphate in the crude potassium car-
bonate) to form what is often termed yellow prussiate of pot-
ash, Potassium Ferrocyanide, Potasii Ferrocyanidum, U. 8. P.,
K,FeC,,N,3H,O, a compound occurring in four-sided tabular yel-
low crystals, This salt contains the elements of cyanogen; yetis not
a cyanide, but a ferrocyanide. It is not poisonous, and is other-
wise different from cyanides ; it will be further noticed subsequently.
From this salt all cyanides are directly or indirectly prepared,
Potassium cyanide, KCN or KCy, the commonest cyanide, may
be obtained by heating potassium ferrocyanide to redness ‘until
gas (chiefly nitrogen) is no longer evolved and iron carbide settles
to the bottom of the molten mass of almost pure cyanide. The
product, carefully poured off and cooled, is an opaque crystalline
mass, Potasii Cyanidum, U, 8. P., containing about 95 percent.
of potassium cyanide, It may also be produced by fusing eight
parts of potassium ferrocyanide with three of potassium carbonate
in a crucible; carbonic anhydride is evolved, iron is set free, and
potassium cyanate, KCNO, is formed, as well as potassium
cyanide :—
K,FeC.N, + K,CO, = 5KCN + KCNO + Fe + ©O,
Mercurie cyanide is produced in crystals by dissolving 1 part of
potassium ferrocyanide in 15 parts of boiling water, adding 2 parts
of mercuric sulphate, keeping the whole hot for ten to fifteen
minutes, and then filtering and setting aside to cool. Besides
mercuric cyanide, Hg(CN),, ferric sulphate and potassium sulph-
ate are formed, and mercury is set free. Any excess of ferrocyan-
ide gives Prussian blue by interaction with the ferric sulphate.
Mercuric cyanide is exceptional in some of its analytical reac-
tions, both as a mercuric salt and as a cyanide. Thus its solution
does not give any precipitate with potassium iodide, (ee reaction
1 of Mercuric Salts, p. 218) unless a drop of hydrochloric acid has
previously been added ; neither does it yield the usual yellow and
white precipitates with potassium hydroxide and with ammonia
water respectively. Similarly it does not give the silver nitrate
reaction for cyanides (ace reaction 1, p, 228).
Cyanogen, CN may be isolated by heating mercuric cyanide,
Hg(CN),, or silver cyanide, AgCN. A small flame of cyanogen
may be obtained by heating a few crystals of mercuric cyanide in
a short piece of glass tubing closed at one end, and applying a
light to the other end as soon as evolution of gas commences ;
brown paracyanogen (CN),, and mercury are also produced. Tn
the case of silver cyanide metallic silver remains, Cyanogen is
a colorless gas which burns with a beautiful peach-blossom colored
flame.
CYANIDES. 267
Experiment.—Dissolvye 2 or 3 grains of potassium ferro-
cyanide in 5 or 6 times its weight of water in a test-tube, add
a few drops of sulphuric acid and boil the mixture, conveying
the evolved gas through a bent glass tube (adapted to the test-
tube by means of a cork) into another test-tube containing a
little water; the product is a dilute solution of hydrocyanic
acid. The official solution, Acidum Hydrocyanicum Dilutum,
is prepared by interaction of silver cyanide and dilute hydro-
ehloric acid, It is a colorless liquid with a characteristic
odor and is exceedingly poisonous. It contains 2 percent. by
weight of hydrogen cyanide, HCN.
2K FeC,.N, + 6H,SO, — FeK,FeC,N, + 6KHSO, + 6HON
To prepare a larger quantity proceed as follows, carrying out
the operation in a well ventilated fume-cupboard :—Dissolve 2}
ounces of potassium ferrocyanide in 10 ounces of water, add one
fluid ounce of sulphuric acid previously diluted with 4 ounces of
water and cooled. Put the solution into a flask or other suitable
apparatus of glass or earthenware, to which are attached a conden-
ser and a receiver arranged for distillation (see p, 130); and
having put 8 ounces of distilled water into the receiver, and pro-
vided efficient means for keeping the condenser and receiver cold,
apply heat to the flask, until by slow distillation the liquid in the
receiver is increased to 17 fluid ounces.' Add to this 3 ounces of
distilled water, or as much as may be sufficient to bring the acid
to the required concentration. The end of the condenser, or an
attached tube, should pass quite into the receiver.
The residue from this reaction is acid potassium sulphate,
KHSO,, which remains in solution, and potassium ferrous ferro-
= serie FeK,FeC,N,, an insoluble powder sometimes termed
everitt’s salt, from the name of the chemist who first made out
the nature of the interaction. The latter compound becomes bluish
green during the operation, owing to absorption of oxygen.
Pure us hydrocyanie acid is a colorless, highly volatile,
intensely poisonous liquid, solidifying when cooled to a low tem-
perature. It may be made by passing hydrogen sulphide over
mercuric cyanide. The official solution of the acid is moderately
stable, but is said to be rendered more so by the presence of a
minute trace of sulphuric or hydrochloric acid. A more concen-
' This operation is peculiarly liable to those sndden and tumultuous
evolutions of vapor, or “bumping,” which often interfere with snecessfal
distillation. Sach bumping may usually be prevented and quiet ebullition
enaured pe ating in the liquid, before beginning to heat it, a few small
fragments of unglazed eartheuware, such as tobacco-pipe stem.
268 THE ACID RADICALS,
trated acid is liable to take up the elements of water and yield
ammonium formate, NH,CHO,. Solutions of hydrocyanie acid
often become brown by formation of what is, apparently, paracy-
anogen, (CN),. According to Williams, aqueous hydrocyanic
acid containing 20 percent. of glycerin can be kept for an almost
indefinite length of time. The official acid should be preserved
in well-stoppered bottles tied over with impervious tissue and
kept inverted, when not in use, in a cool dark place. Unless such
precautions are adopted, the solution rapidly becomes less concen-
trated by escape of gaseous hydrocyanic acid.
Hydrocyanic acid also occurs in cherry-laurel water and bitter-
almond water, *
The methods of determining the concentration of hydrocyanic
acid solutions will be given in the chapter on volumetric and
gravimetric quantitative analysis. The volumetric method is
based on the formation of silver cyanide and its solubility in
solution of alkali-metal cyanides, as described in reaction 1, below.
The hydrocyanic acid used in pharmacy is extremely liable to varia-
tion in strength. It should frequently be tested volumetrically.
Analytical Reactions of Cyanide,
1. To a few drops of the hydrocyanic acid solution pro-
duced in the foregoing experiment, or to a solution of any
cyanide (except mercuric cyanide), add excess of solution of
silver nitrate; a white precipitate of silver cyanide, AgCN,
(Argenti Cyanidum, U.S. P.), is produced. When the precipi-
tate has subsided, pour away the supernatant liquid and -place
half of the residue in another test-tube: to one portion add
nitric acid, and notice that the precipitate does not dissolve ;
to the other add ammonia water, and observe that the precipi-
tate, though soluble, dissolves somewhat slowly, (Silver
chloride, which is also white, is readily soluble in ammonia.)
Silver cyanide dissolves in solutions of cyanides of alkali-
metals, soluble doublecyanides being formed (¢.g., KCN,AgCN,
or KAg(CN),). Silver cyanides also dissolves im hot concen-
trated nitric acid.
Solubility of precipitates in concentrated solutions of salta,—Silver
cyanide and many other precipitates insoluble in acids (or in
alkalies) are often soluble in the saline liquids formed by the ad-
dition of acids and alkalies to each other. Hence the precaution of
adding the latter reagents to separate portions of a precipitate
'' Traces are formed when an electric current passes between carbon
poles in slightly moist air (Dewar); also doring the action of nitric or
nitrous acid on sugar, caramel, or finely divided charcoal,
OCYANIDES. 269
when examining its solubility, or of not adding the one until the
other has been poured away.
Hydrocyanic acid and other cyanides may be detected in the pres-
ence of potassium ferrocyanide by distilling with a large excess of
sodium bicarbonate and testing the distillate for hydrocyanic acid.
In the case of mercuric cyanide it is necessary to add a little
hydrogen sulphide.
2. To a dilute solution of hydrocyanic acid, or of a soluble
cyanide (except mercuric cyanide), add a few drops each of
solutions of a ferrous and of a ferric salt (ferrous sulphate
and ferric chloride); to the mixture add potassium or sodium
hydroxide, magnesia, or sodium carbonate, and then excess
of hydrochloric acid; a precipitate of Prussian blue remains.
The decompositions may he traced in the following equations :—
HCN + KOH = KCN + HO
9KCN + FeSO = FeC.N, + KO,
4KCN + FeCN,= KFeCN,
3K,FeC.N, + 4FeCl, 12KCl “+ Fe(FeCN,),
The test depends on the conversion of the cyanogen radical of
the cyanide into ferrocyanogen by aid of the iron of a ferrous salt,
and the combination of the ferrocyanogen, so produced, with the
iron of a ferric salt.
7 To a solution of hydrocyanic acid add ammonia water
ellow ammonium hydrosulphide, and evaporate the
Tiguid nearly or quite to dryness in a smal! dish, occasionally
adding ammonia tll the excess of ammonium hydrosul!phide is
decomposed ; add water and acidulate the liquid with hydro-
chloric acid, and then add a drop of solution of a ferric salt;
a blood-red solution of ferric thiocyanate will be formed.
This is a very delicate reaction. Some free sulphur in the
cyan ammonium hydrosulphide unites with the alkali-metal
de and forms thiocyanate (NH,CN + 8 = NH,SCN). If the
uid has not been evaporated far enough, ammonium hydro-
5 gl still be present, and give black ferrous sulphide on
the addition of the ferric salt, hence the acidulation prior to the
addition of the ferric salt.
ie acid in the blood.—According to Buchner, the
blood of animals poisoned by hydrocyanic acid, instead of coagu-
Iating | as usual, remains liquid and of a clear cherry- red color for
In one case he obtained the reactions of the acid on
several days,
diluting and distilling the blood fifteen days after death, and
ng the usual reagents to the distillate. Aqueous solution
peroxide changes such blood to a deep-brown color.
270 THE ACID RADICALS.
Schinbein’s test for hydrocyanic acid is said to be extremely
delicate. Filter-paper is soaked in a solution of 3 parts of
guaiacum resin in 100 of alcohol, <A strip of this paper is dipped
in asolution of 1 part of cupric sulphate in 50 of water; a little
of the suspected solution is placed on this paper and exposed
to the air; the paper immediately turns blue if hydrocyanic acid
be present. Orthe paper may be placed over the mouth of an
open bottle of medicine supposed to contain hydrocyanic acid, or
may be otherwise exposed to the vapor of a suspected liquid.
Antidote. —A mixture of ferrous sulphate, solution of ferric
chloride, and either magnesia or sodium carbonate is the recog-
nized antidote in cases of poisoning by hydrocyanic acid or potas-
sium cyanide. Insuch an alkaline mixture the poisonous cyanide,
by interaction with ferrous hydroxide, is at once converted into
innocuous potassium or other ferrocyanide: should the mixture
become acid, the ferric salt present interacts with the soluble
ferrocyanide forming insoluble Prussian blue which is also inert.
From the rapidity of the action of these poisons, however, there is
seldom time to prepare an antidote. Emetics, the stomach-pump,
or stomach-siphon, the application of a stream of cold water to
the spine, and the above antidote, form the usual treatment.
QUESTIONS AND EXERCISES,
Write a paragraph on the discovery of hydrocyanic acid and of cyano-
gen. —Mention the source of the cyanogen of cyanides.—How is potass-
inm ferrocyanide prepared ?—What is the formula of potassium ferro-
eyanide ?—Is potassium ferrocyanide poisonous ?—Write an equation
expressive of the reaction which ensnes when potassium ferrocyanide and
carbonate are brought together at a high temperature.—What are the
properties of cyanogen ?—How may it be obtained ina pure condition?
—How is mercuric cyanide perpared ?—W hat other substances and second-
ary products are formed at the same time ?—How mach hydrocyanic
acid is contained in the official Acidum Hydrocyanicum Dilutum ?—Give
details of the preparation of hydrocyanic acid, and an equation represent-
ing the reaction.—State the proportion of water that must be added to an
wmyheous solution containing 15 percent. of hydrocyanic acid to reduce
the atrength to 2 percent. Ans., 6) to 1.—What are the characters of pure
wudilated hydrocyanic acid ’—How may it be obtained ?—Enumerate the
test for cyanides, giving equations.—Explain the action of the best anti-
ote in cases of poisoning by hydrocyanic acid or potassium cyanide.
Show how it acts in alkaline and acid solutions respectively.
NITRIC ACID, HNO., AND OTHER NITRATES.
Sources. —Nitrogen peroxide, N,O,, is formed to some extent in
the atmosphere by the combination of nitrogen and oxygen under
the influence of the powerful electrical discharges during thunder-
storms, This oxide undergoes further oxidation in presence of
NITRATES, 271
water; and with ammonia, which is always a constituent of the
atmosphere, it forms ammonium nitrate. The nitrates found in rain
no doubt originate partly or wholly in this manner, The oxidation
of ammonia and of the nitrogenous constituents of animal and vege-
table mutters in the soil, favored by darkness by the presence of cal-
cium carbonate, and especially by the presence of the nitrifying
organisms, results in the production of nitrates. Hence nitrates
are commonly met with in natural waters, and in soils and the
juices of plants. In the concentrated plant juices, termed medi-
cinal *‘Extracts,’’ small prismatic crystals of potassium nitrate
on! occasionally be observed. (The cubical crystals often met
with in extracts are potassium chloride.) Nitric acid and other
nitrates are prepared from potassium and sodium nitrates, which,
in turn are obtained from the surface layers of the soil of tropical
countries. J’otassium nitrate (or prismatic nitre, from the form of
its erystals), is produced in and about the villages of India. The
natives simply scrape the surface of waste grounds, mud-heaps,
banks, and other spots where a slight incrustation indicates the
presence of appreciable quantities of nitre, mix the scrapings with
wood-ashes, containing potassium carbonate (to decompose the
calcium nitrate always present), digest the mixture in water, and
evaporate the liquor. The immediate product is purified by care-
ful reerystallizations, and is sent into commerce in the form of
white crystalline masses or fragments of striated six-sided prisms
(Potassli Nitras U.S. P.). Besides its use in medicine, it is
employed in very large quantities in the manufacture of gunpowder,
Potassium nitrate is also largely prepared by the interaction of
potassium chloride and sodium nitrate. Sodiuwm Nitrate occurs in
deposits from 3 inches to 3 yards in thickness on and near the sur-
face, and at any depth down to about 30 feet, in many parts of
Peru, Bolivia, and Chili, but more especially in the district of
Atacama. The mineral is termed ca/iche, and commonly contains
i) percent, of sodium nitrate, The latter is distinguished ns Chili
or Chili nitre, or (from the form of its crystals—obtuse
thombohedra, not cubes) ewbie nifre, and is chiefly used as a ferti-
lizer and as a source of nitric acid, its tendency to absorb moisture
unfitting it for use in gunpowder. In some parts of Europe
potassium nitrate is made artificially by exposing heaps of animal
manure, refuse, ashes, and soi] to the action of the air and the
heat of the sun; in the course of a year or two the nitrogen of the
animal matter becomes oxidixed to nitrates; the latter are removed
by washing. According to Warington, the nitrifying ferment
appears capable of existing in three conditions: (1) The nitric fer-
ment of soil, which convert both ammonium salts and nitrites
into nitrates; (2) the altered ferment, which converts ammonium
salts into nitrites, but fails to change nitrites into nitrates ; and
(4) the surface organism (a bacterium), which changes nitrites into
nitrates. Similar nitrification goes on in well and river waters
272 THE ACID RADICALS,
containing nitrogenous organic contaminations such as sewage,
which thereby tend to become less noxious,
Note,—The word nitric is from nifre, the English equivalent of
the Greek vitpow (nifron), a name applied to certain natural deposits
of natron (sodium carbonate) for which potassium nitrate seems at
first to have been mistaken. Salfpetre is simply sal petre, salt of
the rock, in allusion to the natural origin of potassium nitrate.
Sal prunelia (from sal, a salt, and pruna, a live coal) is potassium
nitrate melted over a fire and cast into cakes or bullets,
The nitric radical is univalent (NO,’),
Nitric Acid.
Experiment,—To a fragment of potassium or sodium nitrate
in a test-tube add a drop or two of sulphuric acid, and warm;
vapor of nitric acid, HNO,, is evolved. The fumes may be
condensed by passing them through a bent delivery-tube into
a second test-tube which is kept cold. The delivery-tube
should not be fitted to the first test-tube by means of a cork as
in the preparation of hydrochloric acid—because the nitric
acid vapors would strongly act on it—but by means of plaster-
of-Paris, a paste of which sets hard on being put aside for a
short time, and is unaffected by the acid.
On a somewhat larger scale, nitric acid may be prepared
by heating, in a stoppered retort, a mixture of equal weights
of potassium nitrate and sulphurie acid; nitric acid distils over,
and acid potassium sulphate remains :—
KNO, + HSO, = HNO, + KHSO,
Potassium Sulphuric Nitric Acid potassium
nitrate acid acid sulphate
The acid potassium sulphate is readily converted into neutral
sulphate (Potassi Su/phas, U. 8, P.) by dissolving in water, adding
potassium carbonate until effervesence ceases, filtering, and setting
aside to crystallize.
Sodium nitrate, on account of its cheapness, is the nitrate from
which manufacturers now usually prepare nitric acid.
Pure nitric acid, HNO,, is colorless liquid of specific gravity 1,52.
The most concentrated acid met with in commerce has a specific
gravity of 1.5 and contains 93 percent. of real nitric acid ; it fumes
disagreeably, is unstable, and, except as an escharotic, is seldom
used. The U. 5. Pharmacoporia contains three nitric acids :—
Fuming nitric acid, specific gravity 1.437; Aecidum Nitriewm,
prepared as above, of secific gravity 1,403 and containing 68 per-
cent. of real acid; and Acidum Nifriewm Dilutum, specific gravity
1,054, containing nearly 10 percent, Either of the more con-
NITRATES. 273
centrated acids, although containing water, is usually termed
“nitric acid.” The official nitric acid, of specific gravity 1.403,
is not a definite hydrous acid although its composition approxi-
mates to the formula 2HNO,, 3H,O ; it distils at 248.9° F. (120,5°
C.), without change. If a less. concentrated acid be heated, it
loses water; if a more concentrated acid be heated, it loses nitric
acid, until the density of 1,403 is reached. Aqua ‘fortis i is an old
name for nitric acid (Aqua fortis simplex, specific gravity 1,22;
Aqua fortis duplex, 1.36). The‘‘concentration’’ of a specimen of
nitric acid is determined by volumetric analysis. Nitric anhydride,
N,0, O, (sometimes, but erroneously, called anhydrous nitric acid) is
crystalline substance formed on passing dry chlorine over
fy silver nitrate,
Metals reduce nitric acid to the various oxides of nitrogen or
even to nitrogen itself, according to the concentration of acid, the
temperature, and the amount of nitrate present. With certain
eek such as zinc and iron, and moderately dilute nitric acid,
some ammonium nitrate is formed. Thus, with zinc,—
1OHNO, + 4Zn = 4Zn(NO,), + NH,NO, + 3H,O
Aqua Regia.—A mixture of 18 parts of nitric acid (U. 8. P.),
and 82 of hydrochloric acid (U. 8. P.), forms the Acidum Nifro-
drochloricum of the Pharmacopwia, The mixture should be set
aside for a week in summer or a fortnight in winter, to insure com-
plete interaction and full development of the chief active product,
chlorine.
Avidum Nitrohydrochloricum Dilutum, U.S. P., which is nitro-
hydrochloric acid diluted with water, may attack organic matter
with evolution of nitrous gases, hence it should not be dispensed
with tinctures, etc., without further dilution.
A ee of concentrated nitric and hydrochloric acids is
A from its property of dissolving gold, the king
of of mets, on being effected by the chlorine which is liber-
—- onOl = NOC] + 2H + Ol,
Pe ise myorosblorio N pores 1 Ww ater Cc hlorine
Coit hE
Nitrosy! chloride isan example of the class of compounds known
as acid ¢ , or acichlorides, formed by the substitution of
chlorine (ch for ‘hydroxy! (OH) in an acid ; thus nitrosyl chloride
be formed from nitrous acid NO.OH. The substitution of
Ol for OH is often useful in deciding how the oxygen and hydro-
gen in a substance are combined, for it is probable that a univalent
atom like Cl can only be substituted for another univalent atom or
and therefore if it replaces O and H they must be present
radical,
itm aaa (-O-H).
THE ACID RADICALS.
Analytical Reactions of Nitrates.
1. To a solution of any nitrate (e.g. KNO,) add sulphuric
acid and then copper turnings, and warm ; colorless nitric
oxide, NO, is evolved, which at once unites with the oxygen
in the tube, giving red fumes of nitrogen peroxide, NO.
2KNO, + 5H,SO, + 3Cu = 2NO + 8CuSO, + 4H,0 +
2KHSO, ; then 2NO + O, = 2NO,
Performed on a larger scale, in a vessel to which a delivery-tube
is attached, the interaction of nitric acid and copper is the process
generally adopted for the preparation of nitric oxide.
Small quantities of nitrates may be overlooked when this test is
employed, the color of the red fumes not being very intense.
Undiluted nitric acid poured upon copper turnings gives rise to
the formation of dense red vapors which contain nitrogen perox-
ide, NO,, nitrous anhydride, N,O,, nitric oxide, NO, and even
nitrogen, N,, the reaction varying somewhat according to the tem-
perature of the mixture and (Ackworth) the quantity of cupric
nitrate in solution, With ordinary copper, dilute nitric acid gives
nitric oxide, 83Cu + SHNO, = 3Cu(NO,), + 4H,0 + 2NO,
Pure nitric oxide may be obtained by treating mercury with a
mixture of sulphuric and nitric acids ; or by treating a mixture of
potassium nitrate 1 part, and ferrous sulphate 4 parts, with sul-
phuric acid and a small quantity of water.
2. Toa cold solution of a nitrate, even if very dilute, add
three or four crystals of ferrous sulphate, shake gently for a
minute in order that some of the sulphate may become dis-
solved, and then pour some concentrated sulphuric acid down
the side of the test-tube, so that it may form a layer at the bot-
tom: a dark-brown or black coloration will appear between
the acid and the supernatant liquid.
This is a very delicate test for nitrates, Nitrites give the reac-
tion without the addition of sulphuric acid. The dark color js due
to the formation of a compound by the interaction of nitric oxide
with a portion of the ferrous salt. The nitric oxide is liberated
from the nitrate by the reducing action of the hydrogen of the sul-
phuric acid, the sulphuric radical of which is absorbed by another
portion of the ferrous sulphate, the latter thereby becoming con-
verted into ferric sulphate.
2HNO, + 31,80, + 6Fc80, = 41,0 + 3Fe,(80,), + 2NO
The process of oxidation is one frequently employed in experi-
mental chemistry; and nitrates, from their richness in oxygen, and
NITRATES. 275
the readiness with which they part with some of it, are the oxi-
dizing agents often selected for the purpose. In the operation they
may so decompose as to yield a metallic oxide, nitric oxide, and
oxygen. Hydrogen nitrate (nitric acid) commonly yields water,
and the other substances mentioned, as shown by the following
equation :—4HNO, = 2H,O + 4NO + 30,
When nitrates, other than nitric acid, are used for the purpose
of oxidation, a strong acid, generally sulphuric, is usually added
in order that nitric acid may be formed, the latter splitting up
more readily than most other nitrates,
The five oxides of nitrogen have now been mentioned, namely :—
Nitrous oxide (laughing-gas)
Nitric oxide _.. RF
Nitrous anhydride
Nitrogen peroxide!
Nitric anhydride
Nitrous oxide is a colorless gas, not altered on exposure to air,
Nitric oxide is also colorless, but gives red fumes in the air, owing
to combination with oxygen, NO, being formed. Nitrous anhy-
dride forms a red vapor condensible to a blue liquid, recent experi-
ments proving thatthe red vapor is merely a mixture of nitric
oxide, NO, and nitrogen peroxide, NO, ; it is only in the liquid
state (at or below —21° C.) that the compound, N,Q, exists, Nitro-
gen peroxide is a red vapor condensible to an orange liquid. Nitric
anhydride is a colorless crystalline solid. The two anhydrides, by
interaction with water, yield respectively nitrous acid, HNO,,
(stable at low temperatures but decomposed on heating), and nitric
acid, HNO,. Nitrous oxide is also probably an anhydride, cor-
ing to hyponitrous acid, H,N,O,. The silver and sodium
salts of the Jatter have the formule Ag,N ,.O, and Na,N,0O,,
The compounds of nitrogen and oxygen, formulat d above,
furnish a good illustration of the law of multiple proportions,
8. Direct the blow-pipe flame against a piece of charcoal
until # spot is red-hot ; now place on the spot a fragment of a
nitrate ; tion ensues.
This reaction does not distinguish nitrates from chlorates, but
indicates the presence of these or other highly oxidized salts, even
when the quantities are small and other substances are mixed
is an intimate mechanical mixture of 75 parts of
nitre, 15 to 12) parts of charcoal, and 10 to 12) parts of sulphur.
1 At low temperatures nitrogen peroxide is represented by the formula
Noy. The molecoles of Nyy decompose, however, on gently warming
to form 2NOp.
276 THE ACID RADICALS.
In order to avoid explosions, the ingredients must be separately
ground, then moistened with water and mixed to a paste, which
is afterward granulated and carefully dried. When fired it may
be said to yield potassium sulphide, K,S (the white smoke), nitro-
gen, N,, carbonic oxide, CO, and carbonic anhydride, CO,, though
the decomposition is seldom complete. The sudden production of
a large quantity of highly heated gas from a small quantity of a
cold solid is sufficient to account for the effects produced by gun-
powder when fired.
4. To nitric acid or any other nitrate add a solution of sul-
phindigotie acid (indigo sulphate); the blue color is discharged.
Free chlorine also destroys the color of this reagent.
Indigo Test Solution, U. 8, P.—This is the sodium or potassium
salt of indigotin-disulphonic acid, C,H, (HS0,),N,0,, dissolved in
water, 1 part in 150,
Antidote.—In cases of poisoning by nitric acid, solution of sodium
carbonate (common washing soda) or magnesia and water may be
administered as antidote,
QUESTIONS AND EXERCISES.
Trace the origin of nitrates.—In what does cubic nitre differ from pris-
matic nitre?—Describe a process by which potassium nitrate may be
obtained artificially. —State the difference between ordinary nitre and sal
prunella.—What is the acid radical of the nitrates ?—How is the official
nitric acid prepared }—Give the properties of nitric acid.—What reactions
ocour when concentrated nitric and hydrochloric acids are mixed 7—How
is nitric oxide prepared ?—Enumerate and explain the tests for nitrates.
—What reduction products may be obtained from nitric acid when it is
employed as an oxidizing agent ?—How is nitrous oxide prepared ?—
Enumerate the five oxides of nitrogen,— What is the nature of gunpowder?
—What quantity of cubic nitre will be required to produce ten carbyys
of official nitric acid, each containing 114 Ibs. ?
HYPOCHLOROUS ACID, HCIO, AND OTHER HYPO-
CHLORITIES.
Experiment.—Place a few grains of red mercuric oxide (or
better, a small quantity of moist freshly-precipitated yellow
mercuric oxide) in a test-tube, half fill the tube with chlorine
water, well shake the mixture, and filter; the resulting liquid
is a solution of hypochlorous acid, mercuric oxychloride
remaining undissolved :-—
2HgO + 2Cl, + H,O = 2HCIO + Hg,O0Cl,
HY POCHLORITES.
By the interaction of hyochlorous acid and oxides or hydroxides,
other pure hypochlorites are formed:—HCIO + NaOH = NaClO
+ H,O.
The action of chlorine on metallic hydroxides gives rise to
“bleaching salts,’’ which are either mixtures of hypochlorite and
chloride, or compounds intermediate between hypochlorite and
chloride (see p. 119, Clax Chilorinata, U.S. P., also p. 91, Liquor
Sode Chlorinate, U.S. P.).
Cl, + 2NaOH = (NaCl0,NaCl) + H,O
2Cl, + 2Ca(OH), = (CaCl,0,, CaCl,) + 2H,0.
The action of strong acids on “‘bleaching salts’’ results in the
evolution of chlorine ; hence the great value of chlorinated lime
in bleaching operations: —
(CaCl,0,, CaCl,) + 2H,80, = 2Cl, + 2CaSO,+ 2H,O
On exposure to air solutions of hypochlorites are slowly decom-
posed with liberation of hypochlorous acid, recognizable by its
peculiar odor:—
2NaClO + CO, + H,O = 2HCIO + Na,CO,
The peculiar odor of this acid, the liberation of chlorine on the
addition of a strong acid, and ‘their bleac ching powers, are the
characters on which to rely i in searching for hypochlorites.
CHLORIC ACID, HC1O,, AND OTHER CHLORATES.
Chlorides ate formed by boiling aqueous solutions of the bleach-
ing salts (chlorinated lime, chlorinated soda, chlorinated potash),
Heat thus converts—
&(NaClO, NaCl)
Chlorinated soda
ANaCl
Sodium
chloride
5KC]
Potassium
chloride
NaClo,
Eollum
chlorate
{
( KCIO,
into / and
into | Potassium and
chlorate
|
{ CaCl,
Calcium
coloride
8{Ca(ClO),, CaCl
dere - al Calelum - snd
into -
chlorate
|
HKCIO, KCl) )
Chlorinated
potash (
}
Ca(ClO,),
)
Potassium Chlorate.
Potassium Chlorate (Potassii Chloras, U. 8. P.), is commerci-
ally made by saturating with chlorine gas a moistened mixture of
$ parts of potassium chloride and 10 of calcium hydroxide, and
278 THE ACID RADICALS,
well boiling the product. Chlorinated lime is first formed; this,
on continued boiling with water, splits up into calcium chloride
and calcium chlorate; and the latter interacting with the potas-
sium chloride yields calcium chloride and potassium chlorate,
6Ca(OH), + 6Cl, = 8[CaCl,, Ca(ClO),] + 6H,0;
8[CaCl,, Ca(ClO),] = Ca(ClO,), + 5CaCl,;
Ca(ClO,), + 2KCl = CaCl, + 2KCI0,
The operation may be conducted on a small scale by rubbing the
ingredients together in a mortar in the foregoing proportions, add-
ing enough water to make the whole assume the character of damp
lumps, placing the porous mass in a funnel (loosely plugged with
fragments of glass) and passing chlorine up through the mass by
attaching to the neck of the funnel the tube delivering the gas.
When the whole mass. has become of a slight pink tint (due to a
trace of permanganate from manganese present as impurity in the
calcium hydroxide) it should be turned into a dish, well boiled
with water, filtered, the filtrate evaporated if necessary, and set
aside; the potassium chlorate separates in tabular monoclinic
crystals, calcium chloride remaining in the mother-liquor. In
this process potassium carbonate may be used in the place of potas-
sium chloride,
6cl, + ¥K,CO, + 6Ca(OH),, =
Chlorine Potassium carbonate Calcium hydroxide
2KCIO, + JaCO, + 6CaCl, + 6H,O
Potassium Calcium Calcium Water
chlorate carbonate chloride
Potassium chlorate is now prepared on the commercial scale hy
the electrolysis of a solution of potassium chloride,
Potassium chlorate is soluble is water to the extent of 6 or 7
parts in 100 at ordinary temperatures. It is usually administered
medicinally in aqueous solution, sometimes also in lozenges (7ro-
chisei Potassii Chloratis, U.S. P.). Potassium chlorate must on
no xecount be rubbed with sulphur or sulphides, in a mortar or
otherwise, friction of such mixtures often given rise to violent
explosions.
Potassium chlorate when heated to a temperature not greatly
beyond its fusing point, yields potassium chloride and oxygen,
and is the salt commonly employed in the preparation of this gas
for experimental purposes. If the action be carried on at as low
a temperature as possible, and be arrested when one hundred parts
of the chlorate have yielded 7.84 parts of oxygen, the residue will
be found to contain only potassium perchlorate, KC)O,, and ehlo-
ride; 1OKCIO, = 6KCIO, + 4KCI 4- 30, (Tead). A higher tem-
perature causes the decomposition of the perchlorate; KOIO, =
CHLORATES. ~
KC! + 20,. When the chlorate is heated with manganese per-
oxide, nv perchlorate is formed,
Sodinm Chlorate (Sodii Chloras, U.8.P.), NaClO,, is prepared in
the same way as potassium chlorate.
Chlorie acid, HC1O,, may be isolated by decomposing barium
chlorate with dilute sulphuric acid, but is unstable, quickly decom-
posing into chlorine, oxygen, and perchloric acid.
Analytical Reactions of Chlorates.
1. To a solution of a chlorate add solution of silver nitrate ;
no precipitate is produced, showing that silver chlorate is solu-
ble in water. Evaporate another portion of the solution to
dryness, and place the residue in a small dry test-tube (or
simply drop a fragment of a chlorate into a test-tube) and
heat strongly ; oxygen is evolved, and may be recognized by
its power of rekindling an incandescent match inserted in the
tube. Boil the residue with water, and again add solution of
silver nitrate ; a white precipitate is produced which
all the characters of silver chloride, as described under hydro-
chloric acid.
2. To a small fragment of a chlorate add two or three drops
of concentrated sulphuric acid; an explosive gas, chlorine
xide, ClO,, is evolved, which somewhat resembles chlorine
in odor, but possesses a deeper color.
3KCIO, + 2H,S0, = 2010, + KCIO, + 2KHSO, + H,O.
Warm the ype part of the test-tube to 150° or 200° F.
(65,5° to 93.3° C, ), or introduce a hot wire; a sharp explosion
ensuies, due to decomposition of the chlorine peroxide into
chlorine and oxygen.
3. Heat « small fragment of a chlorate with hydrochloric
acid; a yellowish green gaseous mixture called ewchlorine is
evolved, Its color is deeper than that of chlorine, hence the
name (from <d, eu, well, and xdJwpds, chléroa, green), It is
really a mixture of that element with chlorine peroxide.
4. Direct the blowpipe-flame against a piece of charcoal
until a spot is red-hot, and then place on the spot a fragment
of a chlorate ; deflagration ensues, as in the case of nitrates.
Perchloric acid, AC\O,.—Crude potassium perchlorate obtained
a8 already described, is boiled (in a fume-cupboard) with hydro-
ehioric acid to decompose any chlorate that may be present, and
then separated from chloride by washing and crystallization, chlo-
280 THE ACID RADICALS.
ride being far more soluble in water than perchlorate. Perchloric
acid is then obtained by distilling the potassium perchlorate with
sulphuric acid; it is stable, and is occasionally administered in
medicine,
Table of the Chlorine Acids.
Hydrochloric acid ; : . HCl
Hypochlorous acid =. ‘ . HClO
Chloric acid... ; : . HClO,
Perchloric acid , ; ; . HCO,
The acid radicals of the above chlorine acids are univalent, as
indicated in the various formule,
Bromates.
Bromates are salts closely resembling chlorates and iodates, The
formula of bromic acid is HBrO,, The presence of bromates, as
impurity, in bromides is shown by the production ofa yellow color,
due to the liberation of bromine, on the addition of dilute sulphuric
acid,
dKBr + KBrO, + 6KH,SO, = 6KHSO, + 3H,O + 8Br,
Iodates.
Jodie Acid, H1O,.—Todine is warmed in a flask with five times
its weight of fuming nitric acid (sp. gr. 1.437), ina fume-cupboard,
until all action ceases. On cooling, iodic acid separates in small
pyramidal crystals. These are separated, the residual liquid eva-
porated to dryness to remove excess of nitric acid, the residue and
the first crop of crystals dissolved in a smal! quantity of boiling
water, and the solution set aside to crystallize, Neutralized with
carbonates or hydroxides, it yields iodatfes.
Potassium iodate and sulphurous acid mutually interact with
elimination of iodine (and formation of a blue color, if starch be
present). Sulphurous acid occurring as an impurity in acetic and
other acids may thus be detected.
2KI0, + 5H,SO, = I, + 3H,S0, + 2KHS0, + H,O
Ferric iodate, or rather Oxryiodate, Fe,O(1O,),, 8H,0, is preeipi-
tated on adding a solution of ferric chloride to solution of potassium
iodate. When heated with sulphuric acidand potassium bichro-
mate, most iodides are decomposed, yielding iodine and a sulphate
of the metal; silver iodide, however, is an exception, as, though it
gradually dissolves, no iodine is separated, and on diluting the
solution and allowing it to cool, a yellow precipitate consisting of
impure silver iodate is deposited.
ACETATES. 231
QUESTIONS AND EXERCISES.
How may hypochlorous acid be formed ?—By what reaction is chlorine
eliminated from hypochlorites ?—State the general reaction by which
chlorates are formed.—Give details of the preparation of potassium chlor-
ate. —Mention the properties of potassium chlorate.—W hat decompositions
oceur when potassium chlorate is heated ?—Find the formula weight of
potassiom chlorate.—What weight of oxygen is produced when 1 oz. of
potassium chlorate is say aad decomposed, and how much potassium
ehloride remains?—One hundred cubic inches of oxygen, at 60° F. and
barometer at 30 inches, weighing 34.203 grains, and one gallon containing
277) cubic inches, what weight of potassium chlorate will be required to
yield 10 gallons of the gas ?—Ans, 5) oz.—Calenlate the weight of potas-
sium chloride obtainable from 100 parts of potassium chlorate.—How may
the presence of chlorides in chlorates be demonstrated ?—Mention the
tests for chlorates.—Give the formula of chlorine peroxide,—What is
enchlorine ?—How is perchloric acid prepared ?— Enumerate the chlorine
acids.— How may iodic acid be made?
ACETIC ACID, HC,H.0,, AND OTHER ACETATES.
Source,—Acetic acid is said to occur naturally in small quantity
in certain plant-juices and animal fluids, but is usually an artificial
product, Much acetic acid is produced during the destructive dis-
tillation of wood. When first discovered in this operation the
acid was regarded as a new one, and was named pyroligneous acid,
a hybrid word from sip, pir, fire, and /ignum, wood, a term still
retained for the crude acid. The latter, neutralized by calcium
carbonate, the solution evaporated to dryness, and the residue gently
heated to drive off volatile tarry matters, yields calcium acetate.
Acetate acid is obtained in a state of purity (mixed with water only)
by starting from this crude calcium acctate, converting it into
sodium acetate, recrystallizing the latter and distilling it with
dilute sulphuric acid. Diluted acetate acid is sometimes sold as
white vinegar, one of the many varities of vinegar. It has been known
a4 wood vinegar for the past sixty or seventy years. [t ia generally
colored brown with caramel! to meet the taste of the public. In
Germany and France large quantities of acetic acid are made by
the oxidation of the alcoho! in inferior wines, in the presence of a
bacterium called Mycoderma Aceti (the Bacterium Mycodermi of
Cohn) ; hence the white-wine and red-wine vinegars (vinegar, from
the French vin, wine, and aigre, sour). This bacterium may be
cultivated, and the manufacture of vinegar from alcohol and water
is carried out by its aid on the large scale. In England also the
domestic form of acetic acid (brown vinegar) commonly has an alco-
holic Origin: infusion of malt and unmalted grain, or sometimes
the latter alone after treatment with sulphuric acid, is fermented ¥
and the resulting alteration of its sugar, instead of being arrested
when the product is an alcoholic liquid, a sort of beer, is allowed
282 THE ACID RADICALS,
to go on to the next stage, acetic acid ; it usually contains from 3
to 6 percent. of actual acetic acid or hydrogen acetate, HO,H O,.
Different strengths of vinegar are sold under the numbers 16, 18,
20, 22, 24, corresponding to the number of grains of anhydrous
sodium carbonate neutralized by one imperial fluid ounce of the
vinegar, or, broadly, to 4, 44, 5, 5) and 6 percent, of acetic acid
respectively. All of these ‘‘brewed vinegars’’ are further colored
with caramel, to suit the popular taste, Vinegar is a generic term
applicable to any one or all varieties. Its essential component is
acetic acid,
Vinegar of Squill (Acetum Scille, U. 8. P.), and Vinegar of
Opium (Acefum Opii, U. 8. P.), or ‘black drop,” contain dilute
acetic acid, that is, wood vinegar.
The acetic radical, C,H,O’,, is univalent.
Acetic acid is regarded as containing the radical acety/ (C,H,O)
united with Aydroxy! (OH), and the acetates as containing metal in
place of the hydrogen of the hydroxyl group. By interaction with
phosphorus trichloride, acetic acid yields acetyl chloride, C,H,OCI.
Acetyl chloride and sodium acetate interact to give sodium chloride
and acetic anhydride,
= (C,H,0),0 + NaCl
C.H,00
By interaction with water, acetic anhydride yields acetic acid :
(C,H,0),0 + H,O = 2C,H,0,.
Note on Anhydrides, —Up to this point an anhydride has been
regarded as a substance derived from an acid by removal of the
whole hydrogen of the acid, together with as much of its oxygen
as with the hydrogen forms water. This does not apply to acetic
anhydride, and must therefore be somewhat qualified. An anhy-
dride is derived from an acid, the acid having lost the whole of its
replaceable hydrogen, and as much oxygen as is necessary to form
water with that hydrogen.
The relation of acetic acid to aleohol will be evident from the
following equation representing the formation of the acid :-—
CHO + 0, = CHO, + HO
Aleohol 7 Acetic ac fd :
Acetates in aqueous solution are liable to decomposition. Tn solu-
tion of morphine acetate a fungoid growth occasionally forms, ace-
tic acid disappears, and morphine is deposited. Solution of ammo-
nium acetate is liable to a similar change, gradually becoming alka-
line,
ACETATES. 283
Experiment,—To a few grains of sodium acetate in a test-
tube, add dilute sulphuric acid, and heat ; acetic acid is evolved,
and may be condensed by passing it through a bent tube
adapted to the test-tube by means of a cork in the usual way,
aC,H,0, H = \H
ia paced seeds teil Lay haa
acelate acid sulphate
The above is the process by which acetic acid is obtained from
sodium or calcium acetate on the large scale. As in the cases of
nitric and hydrochloric acids, the term ‘‘acetic acid’’ is usually
applied to the aqueous solution of the acid, Acidum Aceticum,
U.S. P., contains not less than 36 percent. of hydrogen acetate,
» <Acidum Aceticum Dilutum, U. 8. P., contains not less
than 6 percent. Glacial acetic acid, HC,H,O,, contains no water.
It solidifies to a crystalline mass at temperatures below 63° F, (17. 2°
C.), hence the appellation glacial (from glacies, ice). Good com-
mercial glacial acetate acid (Acidum Aceticum Glaciale, U. 8. P.),
does not contain more than | percent. of water ; it solidifies when
cooled, and again liquefies at about 59° F. (15° C.); its specific
gmivity is 1.049. Although water is specifically lighter than this
acetic acid, yet the addition of water at first raises the sp. gr. of
the acid ; evidently, therefore, contraction takes place on mixing
the liquids: after 10 percent. has been added, the addition of more
water produces the usual effect of dilution of «a liquid with one
pecifically lighter—namely, lowering of the specific gravity,
lacial acetic acid mixes readily with most oils,
Analytical Reactions of Acetates.
1, To an acetate add sulphuric acid, and heat the mixture ;
the characteristic odor of acetic acid is evolved.
Note.—Iodine, sulphurous anhydride, and other substances
which possess a powerful odor, may mask that of acetic acid.
2. it the above reaction, a few drops of alcohol being
first ad to the acetate; acetic ether (ethyl acetate,
CHLCH,O,), possessing a characteristic pleasant odor, is
evol
8. Heat a fragment of a dry acetate (potassium, sodium,
ealeium or barium acetate, for example) in a test-tube, and
notice the odor of the gaseous products of the decomposition ;
among them is acetone, C,H,O, the odor of which is char-
acteristic. Blackening takes place in most cases, A carbon-
ate remains in the test-tube. (See tests for carbonates, )
THE ACID RADICALS.
4. To a solution of an acetate, made neutral by the addition
of acid or alkali, as the case may be, add a few drops of neu-
tral solution of ferric chloride ; a deep-red liquid results, owing
to the formation of ferric acetate, Fe(C,H,O,),. Boil; a red
precipitate of ferric oxyacetate is formed, leaving the liquid
colorless,
Analytical Note.—The student should observe that all normal
acetates are solublein water, Silver acetate, AgC,H,O,, and mer-
curous acetate, HgC,H,O,, are only sparingly soluble in cold water,
but the fact can seldom be utilized in analysis. Hence, precipi-
tation not being available, peculiarities of color and odor, the next
best characters on which to rely, are usually adopted as means by
which acetates may be detected. Most acetates, like many other
organic compounds, char when heated to a high temperature.
——
QUESTIONS AND EXERCISES.
Whatis the formula of acetic acid )—State the relation of acetic acid to
other acetates.—What is the molecular weight of acetic acid ?—Name the
sources of acetic acid.—W hat is pyroligneous acid ?—From what compound
is the acetic acid of most varieties of vinegar derived ?—What is the nature
of the “ Vinegars"’ of Pharmacy ’(—How may acetic acid be obtained from
sodium acetate ?—How much hydrogen acetate is contained in each of the
olficial acetic acids ?—Enumerate the tests for acetates.
HYDROSULPHURIC ACID, HS, AND OTHER
SULPHIDES.
Oceurrence and varieties of Sulphur.—The acid radical of hydro-
gen sulphide, hydrosulphurie acid, sulphydric acid, or sulphuretted
hydrogen and other sulphides, is sulphur, 8. Sulphur oceurs free
in nature, and also in combination with metals, as already stated
in describing the ores of some of the metals. It also occurs in
coal, chiefly as iron pyrites, and sulphur compounds are obtained,
as waste-products, in the manufacture of coal-gas, Most of the
sulphur used in medicine is imported from Sicily, where it occurs
chiefly associated with blue clay. It is purified by fusion, subli-
mation, or distillation. Melted and poured into moulds, it forms
roll sulphur, It is slightly volatile, even on a water-bath, Lf dis-
tilled, and the vapor carried into large chambers, so that it may
be condensed rapidly, it forms crystals which are so minute as to
give the sulphur a pulverulent character; this is eublimed sulphur
(Sulphur Sublimatum, U. 8. P.), or flowers of sulphur, Sulphur,
washed with dilute ammonia to remove traces of sulphuric acid
(often 0.1 percent,, resulting from very slow oxidation of sulphur
SULPHIDES. 285
in ordinary moist air), or, possibly, arsenous sulphide, constitutes
washed sulphur (Sulphur Lotum, U.S. P.). The third common
form, precipitated sulphur (Sulphur Procipitatum, U.S. P.), will
be noticed subsequently. Sulphur also occurs in nature in com-
bination as a constituent of animal and vegetable tissues, as sul-
phurous anhydride, SO,, in volcanic vapors, and as hydrogen sul-
phide in some mineral waters, Sulphur exists in several allo-
tropic forms, of which the following four may be noticed :—1.
Octahedral sulphur—the native and most stable form. 2. Pris-
matic sulphur, obtained by melting the octahedral variety, and
cooling until a crust forms. 3. Plastic sulphur, obtained by
heating melted sulphur to a temperature of (440° C.) 836° F., and
pouring into cold water. 4. Amorphous sulphur, obtained in the
rtion of 5—6 percent. when the octahedral variety is sublimed.
Uotropy.—The existence of more than one variety of the same
elementary substance (as instanced in the varieties of sulphur
enumerated above) illustrates what is known in chemistry as allo-
tropy (@2Aor, allos, another; rpéroc, fropos, condition), Other
instances are met with in the different forms of carbon, phosphorus,
etc.
Black sulphur or Sulphur vivum nigrum is the misleading name
of a grayish mixture of sulphur with a great variety of impurities,
a including arsenic, The article should not be used for
any medicinal purpose.
(Quantivalence,—Sulphur behaves as a sexivalent element in sul-
phurie anhydride, SO,, a substance which will be noticed under
eee acid, and as quadrivalent in sulphurous anhydride, SO,,
while it is frequently bivalent, as in hydrogen sulphide, H,S,
Molecular .—At temperatures between the boiling point
of sulphur (448,4° C.) and about 1000° C., the vapor density of
aoe gradually diminishes as the temperature raises. Above
C., or 30, it is constant and then corresponds to the mole-
sul
1
cular formula §,.
Precipitated Sulphur.
Experiment 1.—Prepare Precipitated Sulphur ( Sulphur Pre-
latum U. 8. P.), or Milk of Sulphur, by boiling a few grains
flowers of sulphur (2 parts) with calcium hydroxide (1 part)
and water in the test-tube (larger quantities in an evaporating-
hasin), filtering, and (reserving a small portion of the filtrate)
adding dilute hydrochloric acid until the well-stirred milky
liquid still has a faintly alkaline reaction to test-paper; sul-
phur “bee csnaeig and may be collected on a filter, washed,
and dried (at about 130° F., 54.4° C,), Excess of acid must
be avoided
in order to prevent contamination of the precipi-
286 THE ACID RADICALS.
tate with traces of arsenous sulphide (from the decomposition
of any thiarsenite, produced from arsenous sul phide present as
impurity in the sulphur employed ).
This is the method of the Pharmacopeia.—Caleium poly-
sulphide and thiosulphate are first formed :—
38Ca(OH), + 658, — 2CaS, + CaSO, + 3H,0
Calcium Sulphur Calcium Calcium Water
hydroxide polysulphide thiosulphate
On adding the acid, both salts are decomposed and (partly in
consequence of an intermediate reaction) sulphur separates :—
2CaS, + CaS,0, + 6HCI = 3CaCl, + 3H,O + 68,
Calcium C crite Hydrochloric Calcium Water Sulphur
polysulphide thiosulphate acid chloride
The calcium polysulphide yields hydrogen sulphide and milk-
white sulphur on the addition of the acid. The calcium thiosul-
phate then yields sulphurous anhydride as well as yellowish sul-
phur. The gases interact and give sulphur and water, very little
hydrogen sulphide escaping : this is the intermediate reaction just
alluded to. A little pentathionie acid (p. 296) is also said to be
formed.
41,8 + 280, = 38, + 48,0
Experiment 2.— Caleareous Precipitated Sulphur. The old
“Milk of Sulphur.”—To a sulphur solution prepared as before
(or to the reserved portion) add a little dilute sulphurie acid ;
the precipitate is in this case largely mixed with calcium sul-
phate:—
2CaS, +- CaS,O, + 3H,SO, + 3H,0 = 3(CaSO,, 2H,0) + 65
Calcium Calefum Sulphur c Water Caleiom sulphate Sulphur
polysulphide thiosulphate acid
Place a little of each of these specimens of “precipitated sul-
phur,” with a drop of the supernatant liquid, on a strip of
glass, place a cover-glass upon each, and examine the precipi-
tutes under a microscope ; the pure sulphur will be found to
consist of minute grains or globules, the calcareous precipitate
to contain comparatively large crystals (hydrous caletum sul-
phate ).
Note.—Some of the precipitated sulphur met with in trade in
England, is still thus mixed with calcium sulphate, most of such
specimens containing two-thirds of their weight of the latter sub-
stance. Formerly, purchasers were so accustomed to the satiny
appearance of the mixed article as to regard real sulphur with sns-
picion, sometimes refusing to purchase it, The mixed article is,
certainly, somewhat more easily miscible with aqueous liquids,
SULPHIDES. 287
The calcareous precipitated sulphur yields a white ash (anhy-
drous calcium sulphate) when a little is burnt off on the end of a
table-knife or spatula or in a porcelain crucible. To ascertain,
exactly, the amount of the sulphate, place a weighed quantity in a
tarred porcelain crucible, and heat until no more vapors are evolved,
The weight of the residual anhydrous calcium sulphate (CaSO, =
135.15), multiplied by 1.264, is the amount of hydrous calcium
sulphate (CaS8O,, 2H,O = 170.9) present in the original quantity
of calcareous sulphur.
Hydrogen Sulphide, Hydrosulphurie Acid, or Sulphuretted Hydro-
aan preparation of hydrogen sulphide was described on p.
Hl ydrosulphides.—Besides ammonium hydrosulphide, which has
already been referred to on p. 100, solutions of sulphides and of
other hydrosulphides may be obtained by the interaction of hydro-
sulphide with solutions of hydroxides. Sodium and potassium
sulphides and hydrosulphides, Na,S and K,S, and NaSH and KSH,
are the most important of these substances :
2KOH + HS = K,S + 2H,0
NaOH + H,S = NaSH + H,O.
Like ammonium hydrosulphide, they act as solvents for the arsenic,
antimony, and stannic sulphides, forming with them thio-salts.
They all dissolve sulphur, producing yellow solutions.
Analytical Reactions of Sulphides and Hydrosulphides,
To a sulphide or hydrosulphide add a few drops of hydro-
ehlorie acid; hydrogen sulphide will probably be evolved,
SE Sopa by its odor. If the sulphide is not acted upon
by the acid, or if free sulphur be under examination, mix a
minute portion with a fragment of solid sodium hydroxide,
and fuse in a silver capsule (or old spoon), When cold,
lace a drop of dilute hydrochloric acid on the fused mass ;
hyd sulphide is evolved, and a black stain due to silver
aiphide, Ag,S, is left on the silver,
The most convenient reagent for detecting sulphide in ammonia
water is cupric ammonium sulphate, which gives a black precipi-
tate of cupric sulphide if a sulphide be present.
_ Sulphur Jodide, 8.1, (Sulphuris Iodidum, U. 8. P.), has already
| mentioned under Iodine. A chloride, 8,Cl,, and bromide,
been
S,Er,, may also be formed from the elements. A mixture of sul-
phur and sulphur chloride jis sometimes met with under the name
of sulphur hypochloride,
288 THE ACID RADICALS.
QUESTIONS AND EXERCISES.
In what forms does sulphur occur in nature f—State the modes of
preparation of the three chief commercial varieties of sulphur.—In what
respect does the atom of sulphur vary in quantivalence ?—Describe the
preparation of hydrogen sulphide.—What are the characters of pure
precipitated sulphur ?—Give equations explanatory of the reactions which
occur in preparing precipitated sulphur?—Describe the microscopic test
for calcareous precipitated sulphur.—Mention a method of detecting cal-
cium sulphate in precipitated sulphur.—Mention the tests for sulphides,
and the character by which hydrogen sulphide is distinguished from
other salphides.—How are sulphides insoluble in acids tested for sulphur?
—How would you detect » trace of sulphide in ammonia solutions?
SULPHUROUS ACID [H.S0,], AND OTHER SULPHITES.
When sulphur is burnt in the air, it combines with oxygen and
forms sulphurous anhydride, SO,, occasionally, but erroneously,
called sulphurous acid, It is a pungent, colorless gas, readily
liquefied on being passed through a tube cooled by a freezing-mix-
ture composed of two parts of well-powdered ice (or of snow) with
one part of common salt. If sulphurous anhydride is passed into
water, heat is evolved and some sulphurous acid [H,SO,], is
apparently formed in solution,
Hydrous sulphurous acid may be obtained in erystals by freez-
ing a concentrated aqueous solution, but it is very unstable.
Quantivalence.—The acid radical of the sulphites is bivalent
(SO,”%. Acid sulphides, such as acid potassium sulphite, KHSO,,
and normal sulphites, such as sodium sulphite, Na,SO,, are known.
Note.—The sulphites are so named in accordance with the usual
rule that salts corresponding with acids whose names end in ows
have a name ending in ite,
Experiment.—To « few drops of sulphuric acid in a test-
tube add a piece of charcoal and apply heat; sulphurous anhy-
dride (mixed with carbonic anhydride) is evolved, and may
be conveyed through a bent tube into a small quantity of cold
water in another test-tube. Larger quantities of the gas may
be made in a flask, The product is Acidum Sulphuroman,
U.S. P.). It contains not Jess than 6 percent. of sulphurous
anhydride.
21.50, + C = OO, + 2H,O + 280,
Sulphuric Carbon Carbonic Water Sulphurous
acid anhydride anhydride
Sulphurous anhydride may also be made by heating copper,
mercury, or iron with concentrated sulphuric acid, a metallic sul-
phate being formed. Also by heating sulphur with sulphuric
acid,
SULPHITES. 289
Sulphides are generally made by passing sulphurous anhydride
into solutions of hydroxides or carbonates, or into water containing
such substances in suspension. In the case of carbonates, carbonic
anhydride escapes. The formula of Sodium Sulphite (Sodii Swu/-
phis, U. 8S. P.), is Na,SO,,7H,O; it occurs in colorless efflores-
cent prisms, soluble in water or alcohol. As ‘‘antichlor’’ it was
formerly used for removing traces of chlorine from paper pulp
(sodium thiosulphate is now employed), The formula of Sodium
Bisulphite (Sodii Bisu/phis, U.S. P.), is NaHSO,. The so-called
Bisulphite of Lime, used by brewers for retarding or arresting
fermentation and oxidation, and employed for various antiseptic
purposes, is made by passing sulphurous anhydride, SO,, into thin
milk of lime. Its specific gravity varies from 1.050 to 1.070, and
it corresponds to from 4 to 6 percent, of sulphurous anhydride,
The so-called meta-bisulphides of potassium and sodium, used in
photography, are really anhydrosulphites, K,S,O, and Na,S,O,,
They may be obtained by passing sulphurous anhydride into hot
saturated solutions of potassium and sodium carbonates, respec-
tively. Sulphurous anhydride is very soluble in alcohol,
Analytical Reactions of Sulphites.
1. To asulphite (sodium sulphite, for instance,—made by
passing sulphurous anhydride into solution of sodium carbon-
ate) add a drop or two of dilute hydrochloric acid; a pecu-
liarly pungent odor is produced (sulphurous acid).
This odor is the same as that evolved on burning sulphur. It is
due, probably not to sulphurous anhydride, 5O,, but to sulphur-
ous acid, H,SO,, formed by the union of the sulphurous anhydride
with either the moisture of the air or that on the surface of the
mucous membrane of the nose. The gas is highly suffocating.
2. To a sulphite add a little water, a fragment or two of
zine, and then hydrochloric acid ; hydrogen sulphide is evolved,
recognizable by its odor and by its action on a piece of paper
placed like a cap on the mouth of the test-tube and moistened
with a drop of solution of lead acetate (a black stain of lead
sulphide being formed). The presence of sulphurous acid in
acetic acid or in hydrochloric acid may be detected by means
of this test :—H.SO, + 6H — HS + 3H,0.
Other Reactions.
To separate portions of a solution of a normal sulphite add
barium nitrate or chloride, calcium chloride, and silver nitrate ;
THE ACID RADICALS,
in each case a white precipitate of a metallic sulphite results.
The barium sulphite is soluble in dilute hydrochloric acid ;
but if a drop or two of chlorine water is first added, barium
sulphate is formed, which is insoluble. The other precipitates
are also soluble in dilute acids. Silver sulphite is decom
ou boiling, sulphuric acid being formed, and metallic silver
set free, the precipitate darkening in color.
To recognize the three radicals in an aqueous solution of sul-
phides, sulphites, and sulphates, add barium chloride, filter, and
wash the precipitate, In the filtrate, sulphides are detected by
the evolution of hydrogen sulphide on the addition of an acid,
In the precipitate, sulphites are detected by observing the odor
of sulphurous acid produced on adding hydrochlorie acid, and sul-
phates are detected by the insolubility of barium sulphate in the
acid,
————e
QUESTIONS AND EXERCISES.
What are the differences between sulphurous acid and sulphurous anhy-
dride, sulphites and acid sulphites ?—State the characters of sulphurous
anhydride.—How is the official sulphurous acid prepared ?—By what tests
may sulphurous acid be recognized in acetic acid )—Give a method by
which sulphites may be detected in presence of sulphides and sulphates,
SULPHURIC ACID, H,SO,, AND OTHER SULPHATES.
Many sulphates occur in nature, The most important of these
are heavy spar, barium sulphate, BaSO.; gypsum, calcium sulphate,
CaSO,,2H,0; and Lpsom sa/t, magnesium sulphate, MgSO,, 7H,0,
Preparation of Sulphuric Acid.—Sulphur itself, or more usually
the sulphur in iron pyrites, is first converted into sulphurous
anhydride by burning in air, and this gas, by oxidation in presence
of moistare, is then converted into sulphuric acid; 5O,+ H,O+0
= H,SO, The oxygen necessary to oxidize the sulphurous
anhydride may be obtained directly from the atmosphere, but the
process is a very slow one. The transference of oxygen to the
sulphurous anhydride, in presence of moisture, to the form sul-
phurie acid, is greatly hastened in practice by the use of nitric
oxide, This gas, when mixed with air, takes up oxygen to form
nitrogen peroxide, NO, which, in turn, is easily reduced again to
nitric oxide by parting with half its oxygen to the moist sulphur-
ous anhydride. The nitric oxide so liberated reunites with oxy-
gen, again forming nitrogen peroxide which again undergots
similar reduction to nitric oxide, so that the process becomes
SULPHATES. 291
virtually a continuous one, a small proportion of nitric oxide
sufficing to convert relatively large quantities of sulphurous anhy-
dride, oxygen, and water into sulphuric acid.
The nitric oxide is in the first instance obtained from nitric
acid, and this from sodium nitrate by the action of a small quan-
tity of sulphuric acid.
The following equations represent the chief steps:—
NaNO, -+ H,SO, = NaHSO, + HNO,,
2H,0 + 380, + 2HNO, = 3H,S0, + 2NO,
2NO + O, = 2NO,,
H,O + 80, + NO, = H,S0,+ NO
Quantivalence.—The sulphuric radical is bivalent (80,”), and
acid as well as normal sulphates are known. Acid potassium
sulphate KHSO,, is an illustration of the former, sodium sul-
phate, Na,SO,, of the latter.
Manufacture of Sulphuric Acid.
Chamber Process.—On the large scale, sulphurous anhydride
together with nitric acid vapor is carried by means of flues into
large leaden chambers, where jets of steam supply the necessary
moisture,’ and into which air isalso passed. The resulting dilute
sulphuric acid, which collects on the floor of the chambers, is
drawn off, and is concentrated by evaporation in leaden, and
finally in glass or platinum, vessels.
Contact .—Sulphuric acid is now made in some places
on the manufacturing scale by aid of the recently perfected ‘‘con-
tact’’ process. In this process sulphurous anhydride, SO,, com-
bines directly with oxygen to form sulphuric anhydride, SO,,
when mixed with oxygen and passed through tubes in which the
mixture is exposed to a large surface of finely divided metallic
platinum in the form of plantinized asbestos. The sulphurous
anhydride is obtained by roasting iron pyrities and must be puri-
fied in a most thorough manner from the last traces of volatile
arsenic compounds and from some other volatile compounds present
as impurities derived from the pyrites; but it remains mixed with
‘In the absence of a sufficient mupply of water vapor, a white crystalline
substance, nitro-eulphonie acid, BO,— NOy’ may be produced (sometimes called
“chamber crystals), The manufacturer of sulphuric acid takes steps to
| ce of so much water vapor that these crystals are never
ted. The followin uations represent the formation of nitro-sulphonic
and its decom poat on by water :— sd Os ph
2505 + 3NO, + HO = 280," No, + NO
BO Vos + H,O = 2JHS0O, + NO, + NO
292 THE ACID RADICALS.
considerable quantities of oxygen and nitrogen from the air drawn
into the furnaces in which the pyrites are roasted. The cooled
mixture of gases is then brought as thoroughly as possible into
contact with platinized asbsetos placed in trays in upright iron
pipes. To begin with, these pipes are heated in order to start the
combination; but they ure afterward exposed to the cooling
influence of the external air, the heat given out by the occurrence
of the reaction being more than sufficient to maintain the tempera-
ture at the point at which the maximum yield of sulphurie anhy-
dride is obtained.
The sulphuric anhydride produced by the reaction is
into previously prepared 98 percent. sulphuric acid in which it is
rapidly absorbed with formation of pyrosulphuric acid, H,5,0,;
and the latter is then mixed with the quantity of water necessary
to reduce it again to the conditon of 98 percent. sulphuric acid or
to sulphuric acid of any required concentration;—
H,SO, + 80, = H,S,0,;
H,S,0, + H,O = 2H,S0,
Ferric oxide may be used as the contact substance instead of
platinized asbestos,
Other processes.—Sulphuric acid may be obtained by other pro-
cesses, as by distilling the ferrous sulphate resulting from the
natural oxidation of iron pyrites by air; but it is not so made at
the present day. Ferrous sulphate was formerly called
vitriol, and the distilled product was called oi/ of vifriol in allusion
to its consistence and origin.
Purification, —Commercial sulphuric acid, prepared by the
chamber process, may contain arsenic compounds, nitrous com-
pounds, and salts (lead sulphate, etc.), Arsenic may be detected
by the hydrogen test (p. 179), or the stannous chloride test (p. 182),
nitrous compounds by means of powdered ferrous sulphate (which
acquires a violet tint if they are present), and salts by observing
the residue left on boiling some of the acid to dryness in a eruci-
ble in a fume-cupboard. If only nitrous compounds are present,
the acid may be purified by heating with about one-half per-
cent. of ammonium sulphate—water and nitrogen being pro-
duced (Pelouze), If arsenic compounds be present, heat with a
small quantity of nitric acid (or sodium nitrate), which converts
arsenous anhydride, Ax,O,, into arsenic anhydride, As,0,, then
add ammonium sulphate, and distil, on a sand bath, ina retort
containing a few small pieces of quartz, or of platinum wire or
foil {to prevent ‘* bumping "—#er p, 267). The arsenic anhydri
remains in the retort (arsenous anhydride would be carried over
with the sulphuric acid vapors). The distillation frees the acid
from other salts (such as NaHSO, and PbSO,) which are not
volatile. Lead may be detected by adding to the concentrated
SULPHATES. 293
acid a few drops of hydrochloric acid, or a crystal of sodium
chloride; the lead chloride precipitated gives a peculiar pearly
opalescence to the liquid.
Pure sulphuric acid, H,SO,, has sp. gr. 1.833. The best ‘oil
of vitriol’’ of commerce, a colorless liquid of oily consistence, has
sp. gr. 1.8263, and contains about 92.5 percent. of hydrogen sul-
phate. The latter is Acidum Sulphuricum, U.8. P., Acidum Sul-
i i B. P. (sp. gr. 1.067) contains about 10 percent.
of hydrogen sulphate. Acidum Sulphuricum Aromaticum, U.8. P.
an acid diluted with alcohol and mixed with tincture of ginger
and oil of cinnamon, also contains about 20 percent. of hydrogen
sulphate. Aromatic sulphuric acid may contain sulphovinic acid in
varying quantity, dependent upon the internal and external
temperature during and subsequent to preparation, the age of the
sample, ete. There are some definite compounds of sulphuric acid
with water; one of these (H,SO,, H,O) may be obtained in crys-
tals.
Sulphuric anhydride, 8O,, occurs in white crystals which interact
with water with great violence, and produce sulphuric acid. As
well as by the direct union of sulphurous anhydride and oxygen,
it may be made by distilling sulphuric acid with phosphoric anhy-
dride: HSO, + P,O, = 2HPO, + SO,. It unites with sulphuric
acid to form ‘“‘fuming sulphuric acid’’ or pyrosulphuric acid, H,8,0,,
formerly made at Nordhausen, in Saxony, by distilling partially
dried and oxidized ferrous sulphate.
Note.—Sulphuric acid is a most valuable compound to all
chemists and manufacturers of chemical substances. By its
, direct or indirect, a very large number of chemical trans-
Analytical Reaction of Sulphates.
oa solution of a sulphate add solution of a barium
white precipitate of barium sulphate, BaSO,, is pro-
Add nitric acid and boil; the precipitate does not
Hs
+
as highly characteristic of sulphates as it has
to be of barium salts (see p. 110). The only error
in its application is that of overlooking the fact
nitrate and chloride are less soluble in concentrated
hydrochloric) acid than in water. On adding the barium
acid liquid, therefore, a white precipitate may be
which is simply barium nitrate (or chloride). The
nce of such a precipitate differs considerably from that of
barium sulphate, but should any doubt exist, water may be
Which will dissolve the nitrate or chloride, but will not
a
p
4.
F
204 THE ACID RADICALS.
2. Mix a fragment of an insoluble sulphate (e.g. BaSO,)
with potassium or sodium carbonate, or, better, with a mix-
ture of both carbonates, and fuse in a small crucible. Digest
the residue, when cold, in water, and filter; the filtrate may
be tested for the sulphuric radical.
This is a convenient method of qualitatively analyzing insolu-
ble sulphates, such as those of barium and lead,
3. Mix a fragment of an insoluble sulphate with sodium
carbonate on a piece of charcoal, taking care that some of the
charcoal dust is included in the mixture. Heat the mixture
in the blow-pipe flame until it fuses, and, when cold, add a
drop of acid; hydrogen sulphide is evolved, recognizable by
its odor.
This is another process for the recognition of insoluble sulphates,
Other preparations of sulphur, and sulphur itself, give a similar
result. It is therefore rather a test for sulphur and its compounds
than for sulphates only.
Antidotes.—In cases of poisoning by sulphuric acid, solution of
sodium carbonate (common washing soda), magnesia and water,
etc,, may be administered as antidotes.
TriosuLpauric Acip, H,S.0,, Anp orHEeR THIOSULPHATES.
The only thiosulphate of much interest in pharmacy is sodium
thiosulphate, Na,S,O,, 5H,O (Sodii Thiosulphas, U.S. P.). It
was formerly known as sodium hyposulphite, and is used in photo-
graphy under the name of “‘hypo,’’ (‘True hyposulphites are now
known, ¢.g. Na 8,O,.)
Thiosulphates may be regarded as sulphates in which one-fourth
of the oxygen has been replaced by sulphur. Thiosulphurie acid
has not been isolated.
Preparation of sodium thiosulphate.—Heat together gently, or set
aside in a warm place, a mixture of solution of sodium sulphite
(Na,SO,) and a little powdered sulphur ; combination slowly takes
place, and sodium thiosulphate is formed. The solution, filtered
from excess of sulphur, readily yields crystals. (The solution of
sodium sulphite may be made by saturating solution of sodium
hydroxide with sulphurous anhydride.) Sodium thiosulphate is
obtained on the manufacturing scale by the interaction of sodium
sulphate with the calcium thiosulphate formed by the action of
atmospheric oxygen and carbonic anhydride on the waste cal-
cium sulphide from the Leblanc soda process.
Uees of wodium thioxulphate in quantitative analysise.—In the
Pharmacopeia, sodium thiosulphate is given as a reagent for the
PERSULPHATES. 298
jantitative determination of free iodine in volumetric analysis.
o a few drops of iodine solution add cold starch mucilage ; a deep-
blue color (starch iodide), is produced. To the product add solu-
tion of sodium thiosulphate until the blue color just disappears.
This reaction is sufficiently definite and delicate to admit of appli-
cation for quantitative purposes, It depends on the combination
of iodine with half of the sodium of the thiosulphate to form sodium
iodide, while sodium tetrathionate, Na,8,O, (from rérpa, tetra, four,
and @ziov, theion, sulphur), is formed at the same time,
2Na,8,0, + 1, = 2Nal + Na,§,0,
Use of “Hypo” in Photography.—Sodium thiosulphate is
largely used in photography to dissolve silver chloride, bro-
mide, or iodide off plateswhich have been exposed in the camera
and developed. Prepare a little of silver chloride by adding
a chloride (sodium chloride) to a few drops of solution of sil-
ver nitrate. Collect the precipitated chloride on a filter,
wash, and add a few drops of solution of sodium thiosulphate ;
the silver salt dissolves, solution of sodium silver thiosulphate
being formed. The solution of this thiosulphate has a re-
markably sweet taste, sweeter than syrup if the solution is con-
centrated. Sodium gold thiosulphate has been employed for
giving a pleasant tint to photographic prints.
Text, —To solution of a thiosulphate add a few drops of dilute
sulphuric or other acid and smell the mixture; thiosulphuric
acid is set free, but at once begins to decompose into sulphur-
ous anhydride, recognizable by its odor, free sulphur, and
water (HS,0,=—50,-+8-+ H,O). Another test for a
thiosu)phide in solution is its power of dissolving silver chloride
with production of a more or Jess sweet liquid.
Persvitrnvric Actp, H,S,0, Ann orneR PERsULPHATES.
Persulphuric anhydride, 8,0,, was obtained by Berthelot in 1887.
Tt yields a solution in water which probably contains some persul-
phurie acid but soon decomposes giving oxygen and sulphuric acid.
Salts of persulphuric acid was first prepared by H. Marshall in
1891, potassium persulphate, K,S.0,, and ammonium persul phate,
| ., being obtained by the electrolysis of saturated solu-
tionsof potassium sulphateand ofammonium sulphate, respectively,
in dilute sulphuric acid. Barium persulphate can be prepared by
the interaction of barium hydroxide with a saturated solution of
ammonium Iphate and evaporation of the solution in vacuo,
The peraulphates are of some industrial importance as bleaching
and general oxidizing agents, and in the latter capacity they serve
= TRE 43D RADICALS
a TUMLIeL 2€ Tacreeds tema apaivsis, Their solutions dis-
AT? TACHGSs Uetts, ied a oo. magnesium, aluminium, copper,
CR. Wildl le 7 .citea id any gas, sulphates being ‘formed :
—1— A>.., = ZN, — Km. Potaxium persulphate was
ie died Te Racket 4 oe Se an. under the name uf * ‘anthion,”’
a ae eee & ame SN GTAREE, & purpme tor which it is,
ewe sl ube atemabc. i 2s spariogiy viable in water. Ammo-
Peth eN stale Lie ae Faced asec! ap pucation in photography
aa aateatl “SE. Shel. a= pers paste is ubtained by the action of
Behah if See ce = $2. BS: PYONL phate. or by the electroly-
SD 0 a salted s red t guid stm suiphate : under the name
Teme 42 seme Gs sate of the salt has been introduced
As Melee & 12 arentive ami ‘eUpepae.
Aairea = seins i Perc tres.—In presence of moisture
Te raukies cwicals Sead rele with furmation of sulphate and
serie oC sree 2K 5,1, — 2H.) = 4KHSO, + O,; con-
MATa DL Zest # litess, anlese treshiv prepared from pure per-
Troe a wots oeeinizace om the addition of barium nitrate;
US os Can te gor a pmvicione af sulphate slowly. on boiling.
— ite tM eh oat gore _ seers = = pereteed Sins wivin the cold but rapidly
a, _ elation cf ehicrimes KO, — 2HCI =
. Relide similarly “decomposed,
sores ee ghee "rhese acid. on warming, causes
wt nram yO x are. re. — Ferrous sulphate is con-
: Tee ros hare. the avlutien becoming dark reddish
_ 2Fe So, = KS0, - Fe,(S0,);-—
cee acid, silver nitrate » preluces a more
POS: site OF > the silver salt (AgHSO,) of
mm: ‘nopersulphurie avid, H,S0,).
Wt TeT2 oe tases In uuantity if sulphuric acid liberated
Boe ee Qe ner nse catinad Ay meansof potassium hydroxide.
So 7 Na Tang formule of the oxyacids of sulphur
eFos gw tat sess til as the seztes of compounds of nit-
eDoangec oun clastming Dalton’s law of multiple propor-
‘a
{
’ a
r
j
ve
‘en tt or an
8 HS, Dithionie Acid 2. HS,O,
. H.SO) Trithienie Acid . . |
scr. Arto. HLS, Teerathionie Acid... HS,0,
Piva cas Ad. aC Pintathionie Acid . HS,O,
Pomntrauce Wed, HAS,
Von ee hurte Acid, HO,
YRS TIONS AND? EN ERCISES,
“Nos, . ous a Do . 4 WW. Mg of sulphurte oo
a Wee as! ort article om
THE ACID RADICALS.
should not yield more than 10 percent. of moisture when dried
at a high temperature, nor more than 4 percent. of ash when
thoroughly incinerated. Thirty grains well shaken with 15
ounces of distilled water containing 0.005 percent, of ordinary
commercial caramel (see Index) should remove at least four-
fifths of the color from the liquid. (Hodgkin. )
Wood Charcoal (Carbo Ligni, U. 5. P.), is a wood similarly
ignited without access of air, On incineration it should yield not
more than 7) percent. of ash.
Decolorizing power of Animal Charcoal.—Animal charcoal, in
fragments is employed in decolorizing solutions of common brown
sugar, for the production of white sugar. Its power, and the nearly
equal power of an equivalent quantity (~jth) of the purified variety,
may be demonstrated on solution of litmus or logwood as well as
on solution of caramel,
Besides these amorphous varieties of carbon there are two crys-
talline varieties ; namely plumbago or black-lead, the material
employed in making the cores of the so-called “‘lead’’ pencils,
which crystallizes in hexagonal plates, and diamond which crys-
tallizes in forms belonging to the cubic system. Diamond is the
hardest substance known. When any form of carbon is burned
in oxygen, carbonic anhydride, CO,, results.
Carbonates are very common in nature, calcium carbonate,
CaCO,, being widely distributed as chalk, limestone, and marble,
Hydrogen carbonate (true carbonic acid) is not known as a sepa-
rate substance, but a solution of carbonic anhydride in water
appears to contain some of this acid. Such a solution (see below)
changes the color of blue litmus-paper, but the change is only
temporary, as the carbonic acid decomposes into water and car-
bonie anhydride when the paper is exposed to the air for a short
time.
Carbonic anhydride, CO,, is a product of the combustion of all
carbonaceous matters, and of the respiration of animals and plants,
It is a constant constituent of the atmosphere, in which it is
present to the extent of about 8 parts in 10,000, and throughout
which it is very equally distributed by diffusion (see p. 30). The
process of carbon assimilation in the vegetable kingdom is depend-
ent upon the presence in the air of this smal] proportion of
carbonic anhydride, and it takes place by the aid of chlorophyll,
the green coloring matter of plants, under the influence of direct
sunlight, The accumulation of carbonic anhydride in confined
air, 80 a8 to greatly exceed the proportion just mentioned, gives
to such air (in crowded rooms, for example) depressing effects ; 4
or § percent, rendering the atmosphere poisonous when taken into
the blood from the lungs. Carbonic anhydride (or carbonic acid,
which is present to some extent at least in all aqueous solutions
CARBONATES. 299
carbonic anhydride) may, however, be taken into the stomach
with beneficial sedative effects; hence, probably, much of the
value of such effervescing liquids as aérated water (often wrongly
called soda-water), lemonade, solutions of the various granulated
pre] ions and effervescing powders, and even potash-water and
soda-water properly so-called. The gas liquefies on the applica-
tion of sufficient pressure at temperatures below 31° C,, and the
liquid solidifies when still further cooled to —58° C. The relative
weights of equal volumes of carbonic anhydride, air, and hydro-
gen, are respectfully 21.89, 14.44, and 1. At ordinary tempera-
tures, water dissolves about itsown volume of carbonic anhydride,
and the weight of the gas dissolved under increased pressure is
proportional to the pressure. An average bottle of aérated water!
contains about five times the quantity of carbonic anhydride which
the water could dissolve without artificial pressure, and when the
cork or stopper is removed, about four-fifths of this quantity
—, while the balance (about equal in volume to the volume
of the water) remains dissolved.
The carbonic anhydride used in the manufacture of sodium
carbonate (the carbonate most frequently used in medicine and in
the arts generally) is obtained by the decomposition of calcium
carbonate (see p. 87),
Carbonie Oxide, CO.—Heat in a test-tube two or three frag-
ments of potassium ferrocyanide with eight or ten times their
weight of sulphuric acid, and as soon as the gas begins to be
evolved, remove the test-tube from the flame, as the action, when
once set up, proceeds somewhat tumultuously. Ignite the car-
boniec oxide at the mouth of the tube ; it burns with a pale-blue
flame, the product of combustion being carbonic anhydride, CO,
Carbonic oxide may also be obtained from oxalic acid (see p.
oxide ia a direct poison. It is generated whenever
coke, charcoal, or coal burns with an insufficient supply of air,
Hence the danger of burning charcoal in braziers (« therwise than
under chimneys) in the more or less closed apartments of ordinary
dwellings. 7 * a * 5 -
£ —Carbonic oxide unites with chlorine in sunlight to
form phosgen (9c, phds, light, and prviu, gennad, I produce),
» & colorless liquid which interacts readily with water,
forming hydrochloric acid and carbonic anhydride, CO + Cl, =
COC, ; COCI, 4+- H,O = 2HC! + CO,.
(Bottled aérated waters yield carbonic anhydride tumnltnously when
new, and soon become “flat,” but yield it less rapidly and more continu-
( when older, and then retain palate-sharpness Jonger, Possibly
this ia due ton solution of true carbonic acid [HyCOs) being less unstable
than a mere solution of the gaa, COs.
THE ACID RADICALS.
Analytical Reactions of Carbonates.
1. To a fragment of marble in a test-tube add dilute
hydrochloric acid ; carbonic anhydride, CO,, is evolved, and
may be conveyed into water or solutions of salts by the usual
delivery-tube.
This is the process usually adopted in preparing carbonic anhy-
dride for experimental purposes. On the large scale, the gus is
prepared from chalk or marble and sulphuric acid, frequent stir-
ring promoting its liberation.
2. Pass the gas into lime-water; a white precipitate of
calcium carbonate, CaCO,, is produced. Solution of lead
subacetate may be used instead of lime-water, and is perhaps
even a more ¢lelicate reagent.
The evolution of an odorless gas on the addition of an acid to a
sult, heat being applied to the mixture if necessary, and the form-
ation of a white precipitate when the gasis passed into lime-water,
afford sufficient eyidence of the presence of a carbonate. The
presence of carbonates in solutions of alkali-metal hydroxides
may be detected by the addition of lime-water. Carbonates in
presence of sulphites or thiosulphates may be detected by adding
acid potassium tartrate, which decomposes carbonates with effer-
vescence, but does not attack sulphites or thiosulphates; or the
substance under examination may first be mixed with excess of
potassium dichromate, and dilute sulphuric or hydrochloric acid
be then added. The evolution of sulphurous anhydride, from the
decomposition of any sulphite or thiosulphate, is entirely pre-
vented by the presence of the dichromate (which would immedi-
ately oxidize it to sulphuric acid) while the evolution of carbonic
anhydride is not interfered with.
3. Blow air from the lungs through a glass tube into lime
water ; the presence of carbonic anhydride is at once indicated
by the liquid becoming turbid. By passing a considerable
quantity of ordinary air through lime-water, a similar effect is
produced, A bottle containing lime-water soon becomes inter-
nally coated with calcium carbonate owing to absorption of
atmospheric carbonic anhydride. .
4. Fill adry test-tube with carbonic anhydride, passing the
gas, by means of a delivery-tube, to the bottom of the fest-
tube. Being rather more than one and a half times as heavy
as air (sp. gr. 1.529), it displaces the latter. Prove the
presence of the gas in the test-tube by pouring it slowly, as if
CARBONATES.
a visible liquid, into another test-tube containing lime-water ;
the characteristic turbidity is obtained on shaking up the
lime-water with the air of the tube. In testing for carbonates
by bringing the evolved gas into contact with lime-water, the
preparation and adaptation of a delivery-tube may often be
avoided by pouring the gas from the generating-tube into that
containing the lime-water, in the manner just indicated.
5. Pass far heale anhydride through lime-water until the
precipitate at first formed is dissolyed. The resulting liquid
ig a solution of calcium carbonate in carbonic acid water, or
probably ealcium bicarbonate, CaH,(CO,),. Boil the solu-
tion; carbonic anhydride escapes, and the carbonate is again
precipitated.
This experiment serves to show how calcium carbonate is kept
in solution in ordinary well-waters, imparting to them the prop-
erty of ‘“‘hardness,’’ and how the fur or stone-like deposit in tea-
kettles and boilers is formed. It should here be stated that
calcium sulphate also produces hardness, and that calcium
carbonate and sulphate with smal! quantities of magnesium car-
bonate and sulphate, constitute the hardening constituents of
well-waters, a curd (calcium or magnesium oleate) being formed
whenever soap is used with such waters. As the formation of
this curd indicates the formation from the soap of insoluble sub-
stances which are devoid of detergent properties, it is obviously
important, in order to avoid waste of soap, that water as free as
possible from these hardening constituents should be employed for
purposes. The hardness produced by the calcium and
um carbonates is termed ‘‘temporary hardness,’’ because
camovable by ebullition ; that produced by the sulphates ‘‘nerma-
nent hardneas,’’ because unaffected by ebullition. The addition
of lime-water, or a mixture of lime and water, removes tempor-
ary hardness, CaH,(CO,), + Ca(OH), r= aCcacO, + 2H,0, and
sodium carbonate, “washing-soda, ? removes both. temporary and
icra hardness, in the latter case sodium sulphate remaining
solution. Barium carbonate (powdered witherite) also decom-
poses calcium and magnesium sulphates, barium sulphate being
pitated and calcium and magnesium carbonates formed; the
tter and the carbonates originally present in the water may then
he precipitated by ebullition or by the action of lime-water, But
the poisonous character of barium salts prevents the use of barium
carbonate to purify water for drinking purposes, as by accident
or an unforeseen reaction a portion might become dissolved.
6. Add a solution of potassium or sodium carbonate to a
magnesium salt; a white precipitate of a basic ‘magnesium
THE ACID RADICALS.
carbonate is produced, but the precipitation is not complete,
On boiling the substance formerly known as magnesia alba
is precipitated (see p. 124),
Thiocarbonates or Sulphocarbonates resemble carbonates in com-
position, but contain sulphur in place of oxygen,
Thicearbonic or Sulphocarbonic anhydride, CS,, commonly termed
carbon disulphide or bisulphide (Carbonei Disulphidum, U.. B
is « highly volatile and inflammable liquid, easily made from its
elements, Sp. gr. 1.256 to 1.257; boiling-point, 46° to 47° C,
When pure it is almost odorless, but a commercial specimen, or
the pure liquid which has been exposed to light for some time,
possesses a disagreeable odor due to impurity. Impure specimens
may be rendered almost odorless by digestion with lime and then
with copper turnings, or by digesting and distilling with mercuric
chloride. It often contains dissolved sulphur, Itisslightly solu-
ble in water (about 1 in 400) forming a useful antiseptic fluid.
Carbon monosulphide, analogous to carbon monoxide (carbonic
oxide), is said to have been obtained,
—
QUESTIONS AND EXERCISES.
Explain the action of hydrochloric acid on animal charcoal in the pro-
cess of purification of the latter—Name the chief natural carbonates.—
What are the formulm of carbonic acid and carbonic anhydride ?—Adduce
evidence of the existence of true carbonic acid.—Carbonic anhydride is
constantly exhaled from the lungs of animals; why does it not accomu-
late in the atmosphere ?—State the specific gravity of carbonic anhydride.
—By what process may carbonic anhydride be obtained for experi-
mental and manufacturing purposes?—Deseribe the action of carbonic
anhydride on potassium or sodium carbonate —How may carbonie anhy-
dride be detected in expired air?—To what extent is carbonic anhydride
heavier than air?—Calculate what quantity of chalk (90 percent. pure)
will be required to furnish the carbonic anhydride necessary to convert
one ton of potassium carbonate (containing 63 percent. of _KzCOs) into
bicarbonate, supposing no gas to be wasted. Avns., 1500 lbs —Define “hard-
ness’’ in water.—How may the presence of carbonates be demonstrated?
OXALIC ACID, H.C.0,,2H.0, AND OTHER OXALATES.
Sources. —Oxalates occur in nature in the juices of some planta,
as wood-sorrel, rhubarb, the common dock, and certain lichens;
but hydrogen oxalate and other oxalates are all made artificially,
The carbon of many organic substances yields oxalic acid when
those substances are boiled with nitric acid, and alkali-metal oxa-
Intes when they are roasted with a mixture of potassium and
sodium hydroxides,
OXALATES. 303
Experimental process, —On the small scale, a mixture of nitric
acid 10 parts, loaf-sugar 2 parts, and water 3 parts, quickly yields
oxalic acid. Red fumes are at first evolved abundantly, and crys-
tals are deposited on cooling, A more dilute nitric acid, kept
warm, acts more slowly, but yields more oxalic acid. The follow-
ing process is more economical,
Manufacturing process.—On the large scale, sawdust is roasted
with caustic soda, the resulting sodium oxalate decomposed by
means of slaked lime, with regeneration of caustic soda and forma-
tion of calcium oxalate. The latter is digested with sulphuric
acid, and the liberated oxalic acid is purified by recrystallization,
Purified oxalic acid.—The acid made from sugar, recrystallized
two or three times, is quite pure. Commercial oxalic acid should
be mixed with insufficient water for complete solution, and the
mixture occasionally shaken ; most of the impurities, remain undis-
solved, and the saturated aqueous solution on evaporation yields
erystals which are nearly pure. Aqueous solutions of oxalic acid
slowly decompose under the influence of light and oxygen,
valence. —The acid radical of the oxalates is bivalent
(C,O.”). The formula of oxalic acid is frequently written (COOH),,
2H,O, Both normal oxalates (R’,C,O,) and acid oxalates
(R’HC,O,) are known.
Salt of sorrel is a crystalline salt intermediate in composition
between oxalic acid and acid potassium oxalate, the crystals con-
eae two molecules of water of crystallization (KH,CO,, H,C,O,,
Analytical Reactions of Ozalates.
1. To solution of an oxalate (e.g., ammonium oxalate) add
solution of calcium chloride; a white precipitate of calcium
oxalate, CaC,O,, is produced. Add to the precipitate excess
of acetic acid; it is insoluble, Add hydrochloric acid ; the
precipitate dissolves.
The formation of a white precipitate on adding a calcium or
barium salt, insoluble in acetic but soluble in hydrochloric or
iitric acid, is usually sufficient proof of the presence of an oxa-
lute. It should be noted, however, that in the presence of sul-
phates, caleium chloride may produce a precipitate of calcium
sulphate which is only slightly soluble in acetic, but is readily
soluble in hydrochloric, acid. In the known presence of sulphates,
oxalate may be tested for by the addition of calcium sulphate to a
solution acidulated with acetic acid only,
2. Heat a fragment of an alkali-metal oxalate (potassium
oxalate, for example) in a test-tube ; decomposition occurs
304 THE ACID RADICALS.
(accompanied by only a slight darkening), carbonic oxide,
CO, is liberated, and carbonate of the metal remains, Add
dilute hydrochloric acid to the residue ; effervescence occurs,
This is a ready test for most ordinary oxalates, soluble or insolu-
ble, and is trustworthy if, on heating the substance, no charring
vecurs, or not more than gives a gray color to the residue. Organic
metallic salts decompose when heated, and leave a residue of car-
bonate, but, except in the case of oxalates, the residue is nearly
always accompanied by much carbon. Insoluble oxalates and
organic salts of such metals as lead and silver are, of course, liable
to be reduced to oxide or even to metal by the action of heat,
Such oxalates may bedecomposed by boiling with solution of sodium
carbonate, and the filtered liquid may be tested for oxalate by
the calcium chloride test (or by means of calcium sulphate, in
acetic acid solution),
Other Analytical Reactions.—Silver nitrate gives, with oxa-
lates, a white precipitate of silver oxalate, Ag,C,O,.—Dry
oxalates are decomposed when heated with concentrated sul-
phuric acid, carbonic oxide and carbonic anhydride escaping.
If enough oxalate be employed, the gas may be washed with
a caustic alkali, which removes the carbonic anhydride, and
the carbonic oxide may then be ignited; it will be found to
burn with a characteristic bluish flame.—Oxalates, when
mixed with water, black manganese oxide (free from carbon-
ates), and sulphuric acid, yield carbonic anhydride which may
be indentified by means of lime-water in the usual manner,
—Not only such insoluble oxalates as those of lead and
silver above referred to, but any ordinary insoluble oxalate,
such as that of calcium or magnesium, may be decomposed by
prolonged ebullition with solution of sodium carbonate ; afler
filtration the oxalic acid radical will be found in the filtrate
as soluble sodium oxalate.
Antidote.—In cases of poisoning by oxalic acid or salt of sorrel,
chalk and water may be administered as antidote (with the view
of producing insoluble calcium oxalate), emetics and the stomach-
pump, or stomach-siphon, being used as soon as possible,
QUESTIONS AND EXERCISES.
How wre oxalates obtained —What is the quantivalence of the oxalic
radical ?—Give the formula of “‘salt of sorrel.""— Mention the chief test for
oxalic acid and other soluble oxalates.—By what reactions are insolu
oxalutes recognized /—Name the antidote for oxalic acid, and describe its
notion,
TARTRATES. 305
TARTARIC ACID, H,C.H,0,, AND OTHER TARTRATES.
Sources. —Tartrates exist in the juices of many fruits; but it is
from that of the grape that our supplies are usually obtained.
Grap-juice contains much acid potassium tartrate, KHC,H,0O,,
which is gradually deposited when the juice is fermented, as in
making wine; for while acid potassium tartrate is not very solu-
ble in water, it is still less so in spirituous liquids, and hence it erys-
tallizes out as the sugar of the grape-juice is gradually converted
into aleohol, It is found, mixed with calcium tartrate, lining the
vessels in which wine is kept; and it is from this crude substance,
termed arga/ or argol, also from the albuminoid yeasty matter or
**lees”’ deposited at the same time, as well as from any tartrate
that may remain in the mare left after the juice has been pressed
from the grapes, that, by rough reerystallization, ‘‘ tartar,’’ still
containing 6 or 7 percent. or more of anhydrous calcium tartrate,
CaC,H,O,, is obtained, From the tartar, tartaric acid and other
tartrates are prepared, In old dried grapes (raisins) crystalline
masses of tartar and of grape-sugar are frequently met with.
Verjuice, that is, verd juice or green juice, isan old name for the
very sour juice of unripe green grapes and of crab apples, It con-
tains tartaric, racemic, and malic acids,
Cream of tartar, purified by crystallization (Potassii Bifartras,
U. 5. P.), occurs asa gritty white powder, or slightly opaque rhom-
bic crystals ; of a pleasant acid taste, soluble in 200 parts of cold
and 16.7 of boiling water, insoluble in alcohol.'
iwalence.—The acid radical of the tartrates is bivalent
(C,H,0,”), and both normal tartrates (R’,C,H,O,) and acid tar-
trates (R/ HC,H,0,) are known. Potassium tartrate (K,C,H,O,),,
HO, and Rochelle salt, potassium and sodium tartrate, the official
Potasii et Sodii Tartras, are illustrations of normal tartrates, while
cream of tartar, KHO,H,O,, is an example of an acid tartrate,
Constitutional formula of tartaric acid : C,H,(OH),(COOH),,
Tartaric Acid.
Tartarie Acid {Acidum Turtaricum, U.8. P.), is obtained by
boiling cream of tartar with water, adding chalk till effervesence
ceases, and then calcium chloride so long as a precipitate is pro-
' A boiling solution of tartar yields a flouting crust of minute crystals on
cooling—jast as milk yields o floating layer of cream; hence the term
cream of tartar. “It iscalled tartar,” svys Paracelsus, “ because it produces
oil, water, tincture, and salt, which burn the patient as tartarus does.”
Tartarna is Latin (Taprapos, Tartaros, Greek) for hell. The products of its
destructive d tion are certainly somewhat irritating in taste and
amell;and the “salt” (potassium carbonate) that is left isdiuretio and in’
Jarger quantities powerfully corrosive.
THE ACID RADICALS.
duced; the two portions of calcium tartrate thus consecutively
formed are thoroughly washed, treated with dilute sulphuric acid,
the mixture boiled for a short time, the resulting calcium sulphate
mostly separated by filtration, the filtrate concentrated by evapor-
ation, any further calcium sulphate that may have deposited
removed as before, and evaporation continued until the solution
is sufficiently concentrated to crystallize on cooling. The caleium
tartrate obtained from nine ounces of cream of tartar requires five
ounces (by weight) of sulphuric acid for complete decomposition,
2K HC,H O, + CaCO, = CaC,H,0, -4- K,C H,0, + H,O + OO,
Acid potassium Calcium Calcium Potassium Water Carbouic
tartrate carbonate turtrate tartrate anhydride
K,C,H,O, + CaCl = CaC,H,O, + 2KCl
Potassium Calcium. Calcium Potassium
tartrate chloride tartrate chloride
CaC,H,0, + H,SO, = CaSO, + H,C,H,0,
Calcium Sulphuric Calcium Turtaric
tartrate acid sulphate acid
Tartaric acid occurs in commerce in colorless crystals or in finely
crystalline powder, It is readily soluble in water and in alcohol.
One gramme dissolved in 5 Ce. of water forms Tartaric Acid Test
Solution, U.S. P. Aqueous solution of tartaric acid is not stable.
Parcels of tartaric acid often contain crystals of a physically
isomeric modification (see Isomerism). It is termed paratartarie
acid (mapa, para, beside) or racemic acid (racemus, a bunch of
grapes), and is acombination of ordinary tartaric acid, whose solu-
tion rotates a ray of polarized light to the right (dextrotartaric or
right-rotating tartaric acid), with levotartaric or left-rotating tur-
taric acid, whose solution rotates a polarized ray to the left.’ Race-
mic acid is inactive in this respect (optically inactive), the opposite
properties of its constituents neutralizing each other, Racemic
acid is leas soluble in alcoho) than tartaric acid.
Potassium Tartrate. (Sve p. 78).
Potassium and Sodium Tartrate. Rochelle Salt.
( See Pp 4] ).
Tartar Emetic. (See p. 188).
Compound Ejfervescing Powder, (Pulvis Effervescens Componitua,
U. 5. P.), or Seidlitz Powder, consists of Rochelle salt (120 grains)
with 40 grains of sodium bicarbonate (the mixture usually wrap
' According to Van 't Hoff and Le Bell, all compounds that cause such
rotation contain at least one atom of carbon with which four different
atoms or radicals are united. Such carbon atoms are termed asymmetric,
TARTRATES, 307
in blue paper) and 34.7 grains of tartaric acid (wrapped in white
paper). When administered, one powder is dissolved ina tumbler
rather more than half full of water, the other added, and the mix-
ture drunk during effervescence.
Analytical Reactions of Tartrates.
1. To a solution of any neutral tartrate, or of tartaric acid
made neutral by addition of sodium hydroxide solution, add
solution of calcium chloride; a white precipitate of calcium
tartrate, CaC,H,O,, is produced. Collect the precipitate on a
filter, wash, place a small quantity in a test-tube, and add solu-
tion of potassium hydroxide: on stirring the mixture the pre-
cipitate dissolyes. Heat the solution: the calcium tartrate is
reprecipitated.
In this reaction a moderate quantity of the calcium chloride solu-
tion should be added at once, and the test should be performed
without delay, otherwise the calcium tartrate will assume a crystal-
line character and be with difficulty dissolved by the caustic pot-
ash. The latter should be quite free from carbonate.
The solubility of calcium tartrate in cold caustic potash solution
enables the analyst to distinguish between tartrates and citrates,
otherwise a difficult matter. Calcium citrate is not soluble, or only
to a slight extent, inthealkali. The absence of much ammonium
salt must be ensured, calcium citrate, as well as tartrate, being
soluble in solutions of ammonium salts.
2. Acidulate a solution of a tartrate with acetic acid, add
potassium acetate, and well stir the mixture; a crystalline
precipitate of potassium bitartrate slowly separates.
This reaction is not applicable in testing for very smal! quantities
of tartrates, the acid potassium tartrate being not altogether insolu-
ble. The precipitate being insoluble in alcohol, however, the
addition of the latter renders the test much more delicate.
5. To a neutral solution of a tartrate add solution of silver
nitrate; a white precipitate of silver tartrate, Ag,C,H,O,, is
produced. Boil the mixture; the precipitate blackens owing
to the reduction of the silver tartrate to metallic silver. Or,
before boiling, add a drop, or Jess, of ammonia water ; a mirror
will form on the tube—adhering well to the glass if the tube
was thoroughly cleansed. When even an insoluble tartrate
is placed in a dry tube with a few fragments of silver nitrate,
a drop, or less, of ammonia water is added, a mirror-like
THE ACID RADICALS.
character is imparted to each fragment of silver salt when the
tube is gently rotated some inches above a Bunsen flame.
Other Reactions,—Tartrates heated with concentrated sul-
phurie acid char immediately, or at least very rapidly,—Tar-
taric acid and the soluble tartrates prevent the precipitation
of ferric and other hydroxides on the addition of alkalies, solu-
tions of double tartrates being formed (which on evaporation
yield liquids that do not crystallize, but, when spread on sheets
of glass, dry up to thin transparent plates or seales). Iron
and Ammonium Tartrate (Jerri et Ammonti Tartras, U.S. P.)
and Jron and Potassium Tartrate (Ferri et Potassti Tartras,
U. 8. P.) are preparations of this kind.—Metallic tartrates
decompose when heated, carbon being set free and metallic
carbonate (or metal in the case of easily reducible metals)
formed, while the gaseous products possess a peculiar, more or
less characteristic smell, resembling that of burnt sugar.
— EE ee
QUESTIONS AND EXERCISES.
State the origin of tartaric acid and other tartrates, and explain the
deposition of argol, crude acid potassium tartrate, during the manufac-
ture of wine.—Give the chemical formula, and the characters of “purified
cream of tartar.’’—Mention the formula and quantivalence of the tartaric
radical.—Write the formule of a number of tartrates.—Give equations
illustrating the production of tartaric acid from purified cream of tartar.
—By what general process may normal or double tartrates be obtained
from acid potassium tartrate ?—Give equations representing the reactions.
—Enumerate the tests for tartrates, and describe the effects of heat on
metallic tartrates.
CITRIC ACID, H,0,H.0,, H,0, AND OTHER CITRATES,
Sources. —Citric acid (Acidum Citricum, U. 8. P.) exists in the
juice of the gooseberry, currant, cherry, strawberry, raspberry, and
many other fruits, as well asin other parts of plants. The pulp of
the fruit of Zamerindus indica (Tamarindus, U. 8. P.) contains
from 1 to 12 pereent. (in addition to 1.5 of tartaric acid, 0.5 of
malic acid, and 8 percent, of ucid potassium tartrate). But it is
from the lemon or lime that the citric acid of commerce is usually
obtained. For this purpose concentrated lemon-juice is exported
from Sicily, concentrated bergamot-juice from the Calabrian coast
of South Italy, and concentrated lime-juice from the West Indies.
Citric acid may be prepared from lemon-juice by the following
process :—The hot juice should be neutralized by the addition of
powdered chalk, the resulting calcium citrate collected on a filter,
CITRATES. 309
washed with hot water till the liquor passes from it colorless (by
which not only the coloring-matter but the mucilage, sugar and
other constituents of the juice are got rid of), then mixed with cold
water, decomposed by means of sulphuric acid, the mixture boiled
for half an hour, filtered, the solution evaporated to a density of
1.21, set aside for 24 hours, then poured off from any deposit of
erystalline calcium sulphate, further concentrated and set aside to
crystallize. If the quantity of calcium citrate decomposed is
unknown, the sulphuric acid may be added until a little of the
supernatant fluid gives, after a minute or two, a precipitate with
solution of calcium chloride. The concentrated solution of citric
acid generally crystallizes very slowly. Shaken violently, however,
in a bottle with a granule or two of solid acid from a previous crys-
tallization, it quickly yields its citric acid in a pulverulent form,
und this drained and redissolved in a very smal! quantity of hot
water yields crystals moderately quickly (Warington).
2H,C,H,0, + 38CaCO, = Ca,(C,H,O.), + 3H,O + 8C0
Citric'acid : Caleium icra c trate Water Carboule
carbonate anhydride
Ca,(C,H,0O 3H,50, = 2H,C,H, 3Ca8
pr cape ad acon e acid rey ‘ 4 A a phate
Citric acid is now manufactured by the citric fermentation of
which takes place in presence of the fungi Cifromyces
Pfeferianua and C. glaber.
The artificial production of citric acid has been accomplished by
Grimaux and Adam, who, starting with glycerin, produce certain
chloro- and cyano-derivatives and ultimately citric acid itself ; it
has also been built up by starting with acetone.
Citrie acid itself is the only citric compound of much direct
importance to the pharmacist, It usually occurs in colorless erys-
tals soluble in .4 of their weight of boiling and in .54 of their weight
of cold water, leas soluble in alcohol and insoluble in ether. A
solution of 80 to 40 grains in 1 ounce of water forms a substitute
for lemon-juice, Syrupua Acidi Cifrici is official. Citrates heated
with concentrated sulphuric acid to about 215° F, (101.6° ©.)
evolve carbonic oxide, and at higher temperatures acetone and car-
anhydride.
Action of heat on citric acid.—Citric acid when slowly heated
first loses its water of crystallization ; afterward (347° F., 175°C.)
the of another molecule of water are evolved and a resi-
due obtained from which either extracts actonie acid, H,C,4,0,,
identical with the aconitic acid (and the acid first termed equisetic)
in various ies of Aconivm and Eyuisetum, baie
—The acid radical of the citrates is trivalent
50," Three classes of citrates are known, in which one,
all three atoms respectively of the replaceable hydrogens
310 THE ACID RADICALS.
atoms of the acid, H,C,H,O,, are replaced by equivalent propor-
tions of metallic radic Constitutional formula of citric acid,
C,H,(OH)(COOH),.
The official Lemon-juice (Limonis Sucecus, U. 8. P.) is to be freshly
expressed from the ripe fruit, to have a specific gravity of 1.030 to
1.040, and to contain from 7 to 9 percent, of citric acid, (H,C,H,0O,,
H,O), The acidity may be ascertained by adding potassium hydrox-
ide, v. 8., till red litmus-paper is turned distinctly blue. Before
applying this test to commercial specimens of lemon-juice, the
absence of notable quantities of sulphuric, hydrochloric, acetic,
tartaric, or other acid must be ensured by application of appropri-
ate reagents. (See also ‘‘ Lemon-juice’’ in Index).
Lime-juice contains an average of 7.84 percent. of citric acid,
rarely rising to 10 percent. and very seldom falling to 7 percent.
Containing but little sugar and mucilage, it requires no addition
of alcohol to preserve it, Lemon-~juice requires about 40 percent,
of proof spirit to prevent fermentation (Conroy).
Analytical Reactions of Citrates,
1. To a dilute solution of any neutral citrate, or of citric
acid carefully neutralized by addition of potassium hydroxide,
add solution of calcium chloride and boil; a white precipitate
of calcium citrate, Ca,(C,H.O.),, is produced. Treat the
precipitate as described in the case of calcium tartrate (p. 307);
it is not perceptibly dissolved in the caustie potash.
An approximate separation of citrate and tartrate can be effected
by means of this reaction. Both radicals are precipitated as cal-
cium salts, and the rapidly washed precipitate is mixed with po
sium hydroxide solution, diluted, and filtered ; the filtrate contains
the tartrate, which is shown to be present by the reprecipitation
on boiling. The precipitate sti]] on the filter is washed, dissolved
in solution of ammonium chloride, and the solution boiled; the
calcium citrate is reprecipitated, The presence of much sugar
interferes with this reaction, A dilute solution of a citrate is not
precipitated by calcium chloride until the liquid is heated: precip-
itation from a concentrated solution, also, is not complete wi
out ebullition of the mixture, This reaction is not thoroughly
satisfactory, calcium citrate being s/ightly soluble in alkalies, in
the solutions of salts produced in the reaction, and, to a very
nent extent, even in cold water, It is readily soluble in acetic
acid.
2. To a neutral solution of a citrate add solution of silver
nitrate; a white precipitate of silver citrate, Ag.C.H.0., is
produced. Boil the mixture; the precipitate does not biacken
rapidly as silver tartrate does, but only after long boiling.
CITRATES. 311
Other Analytical Reactions.—Citric acid forms no precipi-
tate corresponding to potassium bitartrate.-—Lime-water, in
excess, gives no precipitate with a dilute solution of citric acid
or of a citrate unless the solution is boiled, calcium citrate
being slightly soluble in cold but not in hot water; lime-water
usually gives precipitates with tartrates in the cold.—Citrates
do not char immediately when heated with concentrated sul-
phurie acid.—Citric acid and citrates prevent the precipitation
of iron by alkalies, soluble double compounds being formed.
The official Iron and Ammonium Citrate (Ferri et Ammonii
Citraa, U. S. P.) is a preparation of this kind.—Metallic
citrates decompose when feted, carbonates being formed and
earbon set free; the odor of the gaseous products is not so
characteristic as in the case of tartrates.—According to Cail-
letet a cold saturated solution of potassium dichromate turns
a solution of tartaric acid dark-brown, carbonic anhydride
being evolved, while a solution of citric acid only slowly
becomes light-brown.
Puach’s tests for the detection of tartaric acid in citric acid depends
on the well-known difference in the action of sulphuric acid on
tartaric acid and on citric acid. It consists in adding to |
gramme of powdered citric acid in a dry test-tube 10 grammes of
pure concentrated (colorless) sulphuric acid, and keeping the part
of the tube containing the mixture immersed in boiling water for
an hour. The citric acid dissolves with evolution of gas and
frothing to form a lemon-colored liquid, and if the sample be pure
this color undergoes no change within half an hour; but if as
much as one-half percent. of tartaric acid be present, the lemon
color becomes brownish within that time, and in an hour the
mixture is red-brown.
The presence of tartaric acid may also be detected by the
following method:—Add 1 gramme of citric acid to 1 Ce, of a 10
percent. solution of ammonium molybdate, and then a few drops
of a very dilute solution of hy drogen pe sroxide ; ; if tartaric acid is
present, a fine blue color appears: in its absence the color is
yellow. (Crismer, )
QUESTIONS AND EXERCISES,
What is the source of citric acid !—Describe the preparation of citric
acid, giving equations.—Illustrate by formule the various classes of
tartrates and citrates.—State the average proportion of citric acid in
venary, 27ers are the tests for citrates?—How are tartrates sepa-
rated cltrates ?
THE ACID RADICALS,
PHOSPHORIC ACID, H,PO,, AND OTHER PHOSPHATES.
Source. —The source of the ordinary phosphates and of phos-
phorus itself (Phosphorus U. 8. P.) ia the normal calcium phos-
phate, Ca,(PO,),. This is the chief constituent of the bones and
teeth of animals, being derived from the plants on which they
feed, plants again obtaining it from the soil. Compounds of
phosphorus are also met with in the brain, nerves, muscles, blood,
saliva, and, according to Kirkes, even in tissues so simple that
one must assume that the compounds are necessary constituents
of the substance of the primary cell, Phosphates are eliminated
from the system both in the urine and in the fieces,
Phosphorus is obtained from bones by the following processes :
—The bones are calcined to remove all traces of animal matter.
The resulting bone-earth is treated with hot and moderately eon-
centrated sulphuric acid, whereby phosphoric acid and calcium
sulphate are produced :—
Ca,(PO,), + 8H,SO, = 2H,PO, + 8CaSO,
The acid fluid strained from the calcium sulphate and concen-
trated, is mixed with charcoal, coke, or sawdust and dried in an
iron pot, At this stage water escapes, and metaphosphorie acid
remains :-—H,PO, = HPO, + H,O. The mixture is then trans-
ferred to a fireclay retort and strongly heated ; phosphorus yapor
is evolved and is condensed under water while hydrogen and
carbonic oxide escape.
4HPo, + 12C = P, + 2H, + 12C0
The phosphorus is purified by melting under water containing
sulphuric acid and potassium dichromate, and is filtered through
canvas and cast into sticks.
Properties.—Phosphorus is a translucent, wax-like solid (in
sticks or cakes), which emits white fumes, which are Juminous in
the dark, when exposed to the air. Sp. gr. 1.82. Itis soft and
flexible at common temperatures, melts at 111.2° F. (44° C.) ignites
in the air at a temperature a little above its melting-point, burns
with a luminous flame and produces dense white fumes, It is
insoluble in water, but soluble in ether, in boiling oil of turpen-
tine, in carbon bisulphide, absolute alcohol, and chloroform, It
is soluble in oil which has been previously heated for a short
time to about 300° F. (148,8° C.), to expel moisture. Pills con-
taining it are official. ( Pifteler Phosphori, U. Ss. a
Granulated or pulverulent phosphorus is obtained by placing a
quantity of phosphorus under equal parts of aleohol and water in
a bottle, standing the bottle in warm water until the phosphorus
melts, then inserting the stopper (glass, not cork), and shaking
the whole till cold.
PHOSPHATES. 313
Red or ‘Amorphous’? Phosphorus.—Ordinary phosphorus when
kept at a temperature of about 450° F. (232, 2 ©.) in an atmos-
phere from which air is excluded, becomes red, opaque, and in-
soluble in liquids in which ordinary phosphorus i is soluble. The
red modification of phosphorus obtained in this way undergoes
oxidation extremely slowly, and only ignites when heated to near
500° F. (260° C.). Though long regarded as amorphous and
still known as amorphous phosphorus, its structure is really crys-
talline, It is used in the manufacture of several varieties of
matches, and it has the advantage of not emitting the poisonous
fumes given off by ordinary phosphorus.
(uantivalence.—Phosphorus is a quinquivalent element, as seen
in the pentachloride, PC|,, and oxychloride, POCI, ; but it often
exhibits trivalent activity, as seen in the trichloride, PCl,, and
trihydride, PH,,.
Molecula formula, —The vapor density of phosphorus corre-
sponds to the molecular formula, P,. Phosphorus in the state of
vapor thus differs from oxygen, “hydrogen, chlorine, ete., by
having four atoms in its molecule, whilst these elements have
only two,
Phosphoric Acid.
The chief use of phosphorus in pharmacy is for the pro-
duction of Diluted Phosphoric Acid. Phosphorus is boiled
with nitric acid and water until it disappears. The solution,
evaporated to a small volume to remove nitrous compounds
and until the product has a sp, gr. of 1.707, contains 85 per-
cent. of phosphoric acid, H,PO,, and is the Acidum Phoa-
phoricum U, 8. P. The latter, diluted so as to contain 10
percent. of phosphoric acid constitutes the Acidum Phosphori-
cum Dilutum, U. 8. P., a colorless sour liquid of sp. gr. 1,057,
If the necessary appliances are at hand, specimens may be
prepared hy boiling together 103 grains of phosphorus, 14
fluidounces of the official nitric acid, and 2 ounces of water
in a flask attached to a vertical condenser (or some such
arrangement whereby the condensed products are returned to
the flask) until the phosphorus has disappeared.
3P, + 20HNO, + 8H,O = 12H,PO, + 20NO
rus Nitric acid Water P hosphoric acid Nitric oxide
The liquid remaining in the flask is then transferred to a
dish (preferably of platinum), evaporated down to about half
an ounce, and then diluted with the necessary quantity of
distilled water.
314 THE ACID RADICALS.
The use of the water in the earlier part of the process is to
moderate the reaction. Hot concentrated nitric acid oxidizes
phosphorus with almost explosive rapidity, hence the acid must be
diluted in the first instance, and the dilution must be maintained
to prevent the acid from becoming too concentrated by loss of
water, Time is saved by using concentrated acid, but in that
case constant supervision is necessary in order that water may be
added, or the temperature otherwise reduced, should the action
become too violent. Deficiency of nitric acid must also be
avoided, or some phosphorous acid, H,PO,, will be formed.
Markoe, also to economize time, modified the process by add-
ing for every ounce of phosphorus 4 or 5 grains of iodine and,
drop by drop, 25 or 30 drops of bromine, The iodine and
bromine unite with the phosphorus readily, or even with violence
that would be explosive if not controlled by the presence of the
cold fluids (further cooled, if necessary, by immersing the vessel
in cold water), In the course of the reaction it may be assumed
that phosphorus iodide and bromide are first formed. These in
the presence of water immediately yield hydriodic and hydro-
bromic acids (HI, HBr) and phosphoric acid. The nitrie acid
attacks the hydriodic and hydrobromic acids, yielding the lower
oxides of nitrogen (which escape as gas), water, and free iodine
and bromine. The latter unite with more phosphorus, and the
reactions are repeated. This carrying power of a small quantity
of iodine or bromine or both would perhaps be indefinitely pro-
longed if no vapor of these elements or of hydriodic and hydro-
bromic acids escaped with the gases. The phosphorus having
disappeared, excess of nitric acid is mostly got rid of by dropping
in clean rags or paper (nitric oxide, carbonic anhydride, an
water being formed) and, the last portions, by adding oxalic acid
(which even more readily yields similar products). Evaporation
to a syrupy consistence finally removes all traces of iodime, bro-
mine, oxalic acid, and moisture. The product is then diluted to
any required extent.
Experimental process.—A flask, into the neck of which a funnel
is inserted, while a second funnel is inverted so that its mouth
rests within the mouth of the first, is an efficient and convenient
arrangement of heating and condensing apparatus for this pro-
cess, especially if the operation be conducted slowly. (See Fig. 39.)
Solution of phosphoric acid evaporated to a sp. gr., at 25,6° C.,
of 1.850 yields a mass of prismatic crystals, H,PO,, especially if
a crystal or two of the acid from a previous preparation be dropped
into the fluid (Cooper). Further evaporated, it leaves a residue
which melts at a low red heat, yielding pyrophosphoric acid, H,P,0
and finally, metaphosphorie acid, HPO, (Glacial Phosphoric Acid).
(Compare p. 333.) |
A commercial variety of phosphoric acid, containing no lange
PHOSPHATES.
amount of impurity, is prepared by throughly digesting a mixture
of bone-ash, sulphuric acid, and water; filtering, concentrating,
precipitating calcium by means of concentrated sulphuric acid;
and heating until sulphuric acid vapors no
longer escape. It is also prepared by burn-
ing phosphorus so as to obtain phosphoric
anhydride, dissolving the latter in water,
and boiling with a little nitric acid to ox-
idize any lower acids of phosphorus and to
cause any meta- or pyro-phosphoric acid to
take up the elements of water and form
ordinary or orthophosphoric acid.
Prepared from bones, phosphoric acid is
aptto develop fungoid deposits (Jensen).
Prepared from phosphorus, it occasivnally
contains arsenic in the form of arsenic acid,
The latter is detected and removed, to-
gether with any traces of platinum or lead,
by passing hydrogen sulphide for some
time through the warmed acid.
Quantivalence.—The acid radical of the ordinary phosphates, or
orthophosphates, is trivalent (PO,”’). By the replacement of all
or of a part of the replaceable hydrogen of orthophosphorie acid,
H,PO,, trimetallic phosphates (M’,PO,), dimetallic acid phos-
phates (M’,HPO,), or monometallic acid phosphates (M’ H,PO,),
ean be obtained. The phosphates met with in nature or used in
pharmacy are all orthophosphates.
Crude dry calcium phosphate ground with sulphuric acid yields
the very largely used artificial manure termed ‘‘superphosphate.’’
Tt contains acid calcium phosphate, CaH,(PO,),, 2H,O, and cal-
cium sulphate, CaSO,, 2H,0.
The rarer pyrophosphates and metaphosphates, as well as the
phosphites and hypophosphites, will be mentioned subsequently.
Analytical Reactions of Orthophosphates.
1. To an aqueous solution of a phosphate (e.g., Na,HPO,)
add solution of magnesium sulphate or chloride with which
ammonium chloride and ammonia have been mixed (“mag-
hesia mixture”); a white crystalline precipitate of ammonium
magnesium phosphate, NH MgPO,, is produced.
Ammonium chloride is added to prevent the precipitation of
magnesium hydroxide. Arsenates, which have close analogy with
hosphates, give, with magnesia mixture, a precipitate of ana-
logous composition.
THE ACID RADICALS.
2. To an aqueous solution of a phosphate add solution of
silver nitrate; light yellow silver phosphate, Ag,PO,, is pre-
cipitated—completely, if the mixture be neither acid nor alka-
line. To a portion of the precipitate add ammonia water; it
dissolves. ‘To another portion add nitric acid; it dissolves.
By the first part of this reaction phosphates may be dis-
tinguished from their close allies, the arsenates, silver arsen-
ate being brown.
3, To a solution (in a few drops of acid) of a phosphate
insoluble in water (e.g., Ca,(PO,),) add an alkali-metal
acetate (easily made by adding excess of acetic acid to sodium
hydroxide or to ammonia water in a test-tube), and then a
drop or two of solution of ferric chloride; a yellowish white
precipitate of ferric phosphate, FePO,, is produced, insoluble
in acetic acid. ‘Too much ferric chloride must not be added,
or ferric acetate will be produced, in which the ferric phos-
phate is to some extent soluble.
To remove the whole of the phosphoric radical from the solu-
tion add ferric chloride so long as a precipitate is produced,
and boil; ferric phosphate and oxyacetate are precipitated.
To obtain confirmatory evidence of the presence of phosphate
in this precipitate (and to separate the phosphoric radical as
a phosphate of more characteristic appearance), collect the
precipitate on a filter, wash, drop some ammonia water on it,
then ammonium hydrosulphide, and finally wash with water;
black ferrous sulphide remains on the filter, while ammonium
phosphate is present in the filtrate, To the filtrate add mag-
nesia mixture and stir well; a granular precipitate of ammo-
nium magnesium phosphate appears.
4. Dissolve a little calcium phosphate (or any other phos-
phate ) in dilute nitric acid, add solution of ammonium molyb-
date,! and heat gently; yellow precipitate is produced. This
precipitate contains what is somewhat indefinitely termed phos-
pho-molybdic acid—a compound of molybdie acid and phos-
phorie acid (about 4 percent. of H,PO,) with ammonia (nearly
7 percent ).
‘Molybdenum moch resembles lead, hence the name of the metal, from
nédvfdos, molubdos, lead. Ammonium molybdate, (NHy)sMoy, is obtained
by roasting the native molybdenum sulphide, MoS:, so as to convert it
into molybdie oxide or anhydride, MoO,, mixing the latter with water,
adding ammonia, evaporating and crystallizing. Molybdates having the
formule MeMo\; MHMo(); MH Moy, HyMoy (M=1 univalent atom
of any metal) have been obtained, Commercial ammonium molybdate
is commonly the intermedinte salt.
PHOSPHATES. 317
According to von Juptner tartaric acid, even in large excess,
does not prevent the complete precipitation of phosphoric acid by
molybdate solution. The addition of tartaric acid to the molyb-
date solution or to the phosphate is therefore to be recommended,
to prevent the contamination of the yellow precipitate with ferric
compounds,
Note.—The foregoing two reactions are useful in the analysis of
bone-earth, of other earthy phosphates, iron phosphate, and all
phosphates insoluble in water, Only arsenates give similar appear-
ances ; but the acid solution of these may be decomposed by agita-
tion with sulphurous acid, ebullition, and subsequent treatment
with hydrogen sulphide—yellow arsenous sulphide, As8,, being
then precipitated. |
Other Analytical Reactions of Phosphates—Solutions of
barium and calcium salts give, with aqueous solutions of phos-
phates, white precipitates of the respective phosphates, BaH PO,,
or Ba, (PO,),, and CaHPO, or Ca,(PO,),, all of which are
soluble in acetic and the stronger acids.
QUESTIONS AND EXERCISES.
State the direct and indirect sources of phosphorus.—Give equations
explanatory of the isolation of phosphorus from its compounds,—Enumer-
ate the properties of phosphorus.—Mention some solvents of phosphorus.
—How are the two chief varieties of phosphoric acid made? Describe
the precautions to be observed in making this acid.—What are the
strengths of the official acids ?—Write formule illustrative of all classes
of orthophosphates.—What is the composition of farmers’ “superphos-
Pe and how is it prepared ?—Mention the chief test for soluble and
nsoluble phosphates.—By what reactions may phosphates be distinguished
from ersenates ?
Vanapioum V, 50.8, is a very rare element, and is here men-
tioned only because of its exceedingly interesting relation-
ship to nitrogen, phosphorus, arsenic, and antimony; along
with which it forms a series of five closely allied elements,
Discovered, but not isolated, by Sefstrém, and its compounds
investigated by Berzelius, it was obtained in the free state and
fully studied by Roscoe. |
he subjoined formule illustrate the resemblance in com-
ition between some of the compounds of vanadium and
those of nitrogen and phosphorus :—
318 THE ACID RADICALS.
N,O,, N,O, N,O,, NO, N,O. V,0, V,0, V,0, VO, V,O.
Orthophosphates . R’jPO, Orthovanadates. R’,VO,
Pyrophosphates .. R’ 'P, 0, Pyrovanadates . RF’ V O,
Metaphosphates . KR’ PO, Metavyanadates . R/VO,’ O,
Isomorphous Minerals. —
Apatite : ; ; . 8Ca,(PO,),, CaF,
Pyromorphite . . 8Pb, (PO PbCI
dar
Mimetesite 8Pb,( AsO. ),, PbCl,
Vanadinite 3Pb, vO. "PbCl,
BORIC ACID, H,BO., AND OTHER BORATES.
The element boron, like carbon, occurs in the amorphous, graphi-
toidal, and crystalline conditions, It is a trivalent element yield-
ing halogen compounds, such as the chloride, BCI,, and fluoride,
BF... Its atomic weight is 10.9.
The composition of crystallized boric acid (also called doracie
acid), is expressed by the formula H,BO,; but at a temperature
of 212° F. (100° C.) this compound loses the elements of water and
yields metaboric acid, HBO,, which, by further loss of water at
higher temperatures, becomes boric anhydride, B,O,. Metaboric
acid exists in the jets of steam (_/umeroles or suffiont) that issue from
the earth in some districts of Tuscany, and it collects in the water of
the dagoni (lagoons or little lakes) formed at the orifices of the steam
channels. This acid liquid, evaporated by the aid of the waste
natural steam, and neutralized by addition of sodium carbonate,
yields borax, This salt is usually regarded as sodium tetraborate
pyroborate, Na,B,O,, 1OH,O, (Sodii Boras, U.S. P.), analogous
in a sense to potassium dichromate, K,Cr,O,. Native borax or fin-
eal, and other borates, are also found in Thibet, Nevada, Peru,
C *hili, and, abundantly, in California in the Colorado district.
Californian borax is represented as forming large portions of the
crystalline bed of a dried-up lake. Borax is also made on a large
scale by boiling native calcium borate with sodium carbonate, It
is sometimes termed sodium biborate. It occurs in transparent
colorless crystals, sometimes slightly effloresced, or a white odor-
less powder, with a weak alk: aline reaction ; insoluble in aleohol
(90 percent.), soluble in 25 times its weight of cold, and in half
its weight of boiling water.
Fused borax re: adily dissolves metallic oxide ‘S, #8 will have been
noticed already in testing for cobalt and manganese (compare
experiment 3, p. 140, and experiment 3, p. 142). Hence, besides
its use in medicine, borax is employed as a Aux in refining and
BORATES. 319
other metallurgic, and in ceramic, operations ; it is also an ingre-
dient in starch glazes. Glyceritum Boroglycerini, U. 8. P., is
obtained by adding boric acid to glycerin heated to a temperature
not exceeding 150°C. Borax honey formed of 2 parts of borax
to 16 of honey, is a very old antiseptic for the mouths of infants
troubled by the growth called ‘‘thrush.’’
(Quantivalence.—The acid radical of the borates is trivalent
(BO,’”) ; that of the metaborates univalent (BO,’).
Experiment 1.—Tvo a hot concentrated solution of borax
add a few drops of sulphuric acid and set aside ; on cooling,
crystalline scales of boric acid, H,BO, ( Acidum Boricum,
U.S. P.), are obtained, The acid may be purified by collect-
ing on a filter, slightly washing, drying, digesting in hot alco-
hol, filtering, and setting aside; pure boric acid is deposited.
The acid may also be crystallized from water.
Boric acid occurs in colorless, pearly, lamellar crystals or irregu-
Jar masses of crystals ; unctuous to the touch ; taste faintly bitter,
leaving a sweetish after-flavor in the mouth. Soluble in 18 parts
of water, in 4.6 of glycerin, in 15,3 of alcohol at 25° C,, and in 3
of boiling water. It changes the color of litmus to wine-red in the
cold, a hot saturated solution giving a bright red color ; turmeric
paper, moistened with an aqueous solution, even when slightly
acidulated with hydrochloric acid, becomes brownish-red on gently
drying, and this color changes to a greenish-black if solution of
potassium hydroxide be added. The solution in alcohol burns
with a flame tinged with green, especially when the solution is
acidulated with sulphuric acid. Boric acid liquefies when warmed,
and on careful heating loses 43.6 percent. of its weight, the pro-
duct solidifying on cooling, to a brittle glass-like mass.
Boric acid is a very weak acid and only slowly decomposes car-
bonates ; a solution of borax possesses a strongly alkaline reaction.
Boric acid is extensively used as an antiseptic in the preserva-
tion of foods, especially in the production of ‘‘mild-cured’’ bacon
and ham, ete.
Experiment 2.—Mix together 1 part of boric acid, 4 parts
of acid potassium tartrate, and 10 to 20 of water ; evaporate
to @ syrupy consistence, spread on plates and set aside for dry
scales to form. The resulting substance is far more readily
soluble in water than either of its constituents, and is known
as potassium boro-tartrate, or soluble cream of tartar. The
Prussian fartarus boraxatus differs from the foregoing Freiuch
variety in containing 1 part of borax to 5 of acid potass um
tartrate.
320 THE ACID RADICALS.
Analytical Reactions of Borates.
1. Dip a piece of turmeric paper (paper soaked in tincture
of turmeric tubers and dried) into a solution of boric acid ; it
is colored brown-red, as by alkalies.
The usual mode of applying this test is as follows :—Add to a
solution of any borate a few drops of hydrochloric acid, immerse
half of a slip of turmeric paper in the liquid, then dry the paper
over & Bunsen flame to develop the brown color. (Concentrated
hydrochloric acid or ferric chloride would produce a somewhat
similar change of color.) Place a drop of sodium hydroxide solu-
tion on the browned turmeric paper: a dark green color is pro-
duced,
2. To a fragment of a borate, pyroborate, or metaborate
(borax may be used) in a small dish or watch-glass, add a
drop of concentrated sulphuric acid and then a little alcohol ;
warm the mixture and set fire to the alcohol; the resulting
flame is tinged green at its edges by the volatilized metaboric
acid.
The liquid should be well stirred while burning. Salts of cop-
per and some metallic chlorides produce a somewhat similar color.
The flame-test may also be applied to a small quantity of a mix-
ture of the borate with sulphuric acid on a platinum wire. Gly-
cerin may be used instead of sulphuric acid (Iles), the reaction
with borax being, according to Dunstan, the formation of glyceryl
borate, C,H, BO,, water, and sodium metaborate ; the glyceryl bor-
ate and water interacting immediately to form boric acid and gly-
cerin. If the borax and the glycerin are both anhydrous no boric
acid is formed as the water resulting from the decomposition is
immediately volatilized by the heat.
Other Analytical Reactions.—In a moderately concentrated
solution of borax, a barium salt produces a white precipitate
of barium metaborate, Ba( BO,),, soluble in acids and certain
salts. Silver nitrate also affords a white precipitate of silver
metaborate, AgBO,, soluble in nitric acid and in ammonia,
Calcium chloride, if the solution is not too dilute, gives a
white precipitate of calcium metaborate, Ca( BO,),.
QUESTIONS AND EXERCISES.
Illustrate the relations of vanadium to nitrogen and to phosphorus by
formulw of compounds of each element.—Desecribe the preparation of
borax.—Give the formuls of boric acid metaboric acid, and borax,—Men-
tion the tests for horntes or metaborntes,
BENZOATES, 321
The foregoing acids and salts comprise those which are
commonly employed in ordinary medical or pharmaceutical
operations. There are, however, many others which are oceasion-
ally used. The chief of these will now be shortly noticed ; they
are arranged in alphabetical order to facilitate reference.
————
SALTS OF RARER ACID RADICALS.
Benzore Acip, HC,H,O, ann oTHEeR BENzOATES.—
Slowly heat a fragment of benzoin (Gum Benjamin) (Benzo-
inum, U.S. P.)' in a test-tube ; benzoic acid ( Acidum Benzo-
icum, U. 5S. P.) rises in yapor and condenses in small, white,
feathery plates and needles on the cool sides of the tube, If
the benzoin is first mixed with twice its weight of sand or
roughly powdered pumice-stone, and the heat very cautiously
applied the product will be less likely to be burnt, and a larger
quantity will be yielded. By repeated sublimation 10 to 15
percent. may be obtained.
A more economical process is to boil the benzoin with one-
fourth its weight of calcium hydroxide, filter, concentrate ;
decompose the dissolved calcium benzoate by adding hydro-
chloric acid; collect the precipitated benzoic acid, press
between filter-paper, dry, and sublime in a tube or other
vessel.
2HC.H,O, + Ca(OH), = Ca(CH,0,), + 2H,0
Benzolc acid Calcium Calcium Water
(impure) hydroxide benzoate
Ca(CH.0,), + 2HCl = CaCl, + 2HC,H,O,
Calcium Hydrochloric Calcium Benzole acid
benzoate acid chloride (pure)
There is always associated with the product a minute quantity
of a mixture of volatile oils of agreeable odor, suggesting that of
hay, and yielding, according to Jacobsen, methyl benzoate,
guaiacol (methoxycatechol), catechol, acetylguaiacol, benzyl] ben-
zoute, benzophenone, and benzoylguaiacol.
Benzoic acid is also prepared on a large scale artificially from
naphthalene, one of the crystalline by-products in the distillation
of coal for gas. The naphthalene is oxidized by nitric acid to
naphthalic or phthalic acid :—
80 = HCHO H,C,0
tans Oxygen palate acid : ont
' Sumatra benzoin (excluding wood) is soluble in ether, and the dis-
solved substance yields 0.01 percent. of ash.
THE ACID RADICALS,
The phthalic acid is neutralized by adding lime, and the
calcium phthalate is heated with calcium hydroxide for several
hours in a covered vessel at a temperature of about 640° F.
(387.8° C.), Calcium benzoate and carbonate are formed, and
benzoic acid is set free by the action of hydrochloric acid on the
mixture,
2Ca0,H,O, + ps Seta = Ca(C,H,0,), + 2Ca00,
Calcium Calcium Calcium Calcium
phthalate hydroxide benzoate carbonate
The crystalline deposit formed when oil of bitter almonds
(benzoic aldehyde or benzaldehyde) is exposed to the air is ben-
zoie acid,
20,H,COH + O, = 2C,H,COOH or 2HC_H,O,
Benzaldehyde Oxygen Benzoic acid
Pure sublimed benzoic acid is also obtained from hippurie acid
(p. 325).
Jacobsen has prepared benzoic acid from benzotrichloride
(trichloromethylbenzene, C, H,CCl,, one of the trichlorotoluenes)
by heating with glacial acetic acid and zine chloride. This acid,
if not very highly purified, may give a green color to the flame
when heated on platinum wire with a little copper oxide, In
artificial benzoic acid the fragrant volatile oil characteristic of the
acid from benzoin is absent.
Properties.— Benzoic acid is slightly soluble in cold water,
more so in hot, and readily soluble in aleohol (90 percent. ).
It melts at 250.5° F. (121.4° C.) and boils at 462° F.
(238.8° C.), volatilizing with only a slight residue. Heated
with lime it yields benzene. It dissolyes in cold sulphuric
acid without decomposition, and is deposited again on dilu-
tion ; the traces of odoriferous and other substances present in
the acid obtained from benzoin only slightly color the fluid,
even on warming gently.
Official benzoates.—To a little benzoic acid add a few
drops of ammonia water or of sodium carbonate solution; the
acid readily dissolves, forming the corresponding benzoate
(Ammonit benzoaa, U.S. P., NH,C_H.O., or Sodit Benzoas,
U. & P., NaC.H,0,). With ammonia water the reaction
|. ee
HCHO, + NH, = NHCHO,
| C, 6
Benzoic acid Ammonia Ammoniuss benzoate
On evaporating the solution, which is kept slightly alkaline
throughout the evaporation by the addition of ammonia,
CACODYLATES, ETC: 328
crystals of ammonium benzoate are deposited. Berrzoic acid
also interacts with other alkaline liquids, forming benzoates.
Lithium Benzoate ( Lithiit Benzoas) is official.
Test for benzoates.—To a solution of a benzoate add a
drop or two of sulphuric or hydrochloric acid ; a white crys-
talline precipitate of benzoic acid separates. To another
portion of the solution, carefully made neutral if necessary,
id a drop or two of neutral solution of ferric chloride; a
reddish precipitate of ferric benzoate results.
Cacopyiic Acip (CH,),AsO.OH.—This is a crystalline acid
which is formed on exposure to air of cacody] oxide, (CH,),As,O
(Cadet’s fuming liquid), an exceedingly poisonous and evil-smell-
ing liquid produced by heating a mixture of arsenous anhydride
and potassium acetate. Sodium cacodylate, (CH,),AsO,Na, 3H,O,
ferric cacodylate, [(CH,),AsO,],Fe, and some other salts are now
used in medicine.
A salt somewhat analogous to sodium cacodylate, corresponding
to the acid CH,AsO(OH), (methyl-arsenic acid), and represented
by the formula CH,AsO(ONa),, 5H,O, has been introduced into
medicine under the name arrhena/, This salt has been called
sodium methy arsenate, a name which is quite inappropriate as
the salt is not an arsenate,
Carmtinic Acip, C,.H,.O,,.—This is the coloring principle
(about 10 percent.) of the dried female cochineal insect, Coceus
Cacti, (Coceusz, U.S. P.). The carmine of trade, when unadul-
terated (see P. J., 1859-60, p. 546) is carminie acid associated
with 2 or 8 percent, of alumina and lime, or, occasionally, of tin
oxide or albumen. It should be wholly soluble in ammomia
water, giving aclear, rich purple liquid. Carmine with French
chalk, or starch, constitutes face rouge or animal rouge.
Merrick tests the relative value of several samples of cochineal
or carmine by observing how much solution of potassium perman-
ganate is required to change the color of a decoction to a faint
pink, The silvery coating of cochineal is a wax, coccerin,
CeTraric Acrp, H,C,,H,,0,, is the bitter principle of Iceland
moss, In the lichen it is associated with much starch. A fatty
acid, lichenstearic acid, is also present.
CixwAmic Actp, C,H,COOH,—Benzoic acid is distinguished
from an allied acid, cinnamic acid (occurring in Balsams of Perw
and Tolu, in Storax, and sometimes in Benzoin), by not yielding
benzaldehyde, C,H,COH (oil of bitter almonds), when distilled
with a mixture of potassium dichromate and sulphuric acid, or
when triturated with half its weight of potassium permanganate.
Old hard balsam of tolu yields cinnamie acid on boiling with lime
and water and precipitating by the addition of hydrochloric acid.
Jacobsen makes cinnamic acid artificially by the prolonged inter-
O24 THE ACID RADICALS,
action of glacial acetic acid and benzodichloride in the presence
of zine chloride,
Cyanic Actp, HCNQO, AND OTHER CYANATES.—The reducing
action of potassium eyanide, KCN (or ferrocyanide, K,FeO,N,) on
many metallic oxides, is due to the readiness with which it takes
up oxygen and forms cyanate, KONO.
Experiment.—F use a few grains of potassium cyanide in a
small porcelain crucible and add powdered lead oxide; a
globule of metallic lead is at once formed, excess of the oxide
converting the whole of the potassium cyanide into potassium
cyanate ;—KCN + PbO = KCNO + Pb.
Potassium cyanate, KCNO, or better, lead cyanate, Pb(CNO),,
treated with ammonium sulphate, yields ammonium cyanate,
NH,CNO; and solution of ammonium cyanate, when eviporated
to dry ness, leaves a residue of wrea, CON, H,, the most important
constituent of urine, and the chief form in which the waste
nitrogen is eliminated from the animal system, The process will
be more fully deseribed pateerenes in connection with urea.
EMBELIC ACID, HO,H appears to be the active principle
of the vermifuge fruit ofa mbelia Ribes and Embelia Robusta—
Warden,
Formic Actp, HCHO, The red ant (Formica rufa) and
several other insects, when irritated, eject a strongly acid, acrid
liquid, which contains formic acid; the acid is also contained in
the leaves of the stinging-nettle.
Preparation.—Formic acid may be prepared artificially by
heating equal weights of oxalic acid and glycerin to a tem-
perature of from "212° to 220° F. (100° to 104.4° C.) for
fifteen hours, and then distilling the mixture with a consider-
able volume of water. The formic acid, mixed with water,
slowly passes over, glycerin being regenerated. The dilute
acid may be obtained in a concentrated form by neutralizing
with lead carbonate, filtering, evaporating to a small yolume,
collecting the deposited crystalline lead formate, drying,
decomposing in a current of dry hydrogen sulphide, at 212° F-
(100° C.), and rectifying the resulting syrupy acid from dry
lead formate. It should be fluid at 48° F. (8.9° C.) and boil
at 212° F. (100° C.). The following are the chief reactions :—
C.H(OH), 4 1.0.0 — (.H,OHC,O, + 2,0
‘Glycerin : oxalic “acid Glyceryl hydroxyoxalate Water
C,H,OHC,O, + 2H.0 = C,H,(OH), + HCHO, + CO
Carbon
diye ery! Water Glycerin
hydroxyoxalate
FORMATES, ETC. 325
Formic Acid may be instructively though not economically pre-
pared by the oxidation of methyl alcohol (wood-spirit), just as
acetic acid and valerianic acid are obtained from ethyl alcohol
and amy! alcohol respectively—
CH,OH + 20 = HCOOH + 4H,0
Methyl alcohol Oxygen Formic acid Water
Tests. —Formic acid does not char when heated alone or with
sulphuric acid, but splits up into carbonic oxide and water, It
is recognized by this property and by its reducing action on salts
of gold, platinum, mercury, and silver. Itis solid below 32° F,
(0° C.).
GALLIC Actp.—See TANNIC ACID,
HeMIpEsmic Acitp.—The supposed active principle of hemi-
desmus root.
Hippuric Acip, HC,H,NO,, is a constituent of human urine
(much increased on taking benzoic acid), but is prepared from
the urine of the horse (hence the name, from imzoc, /ippoa, a
horsef, or better, from that of the cow. To such urine add a little
milk of lime, boil for a few minutes, remove precipitated phosphates
by filtration, drop in hydrochloric acid until the liquid, after well
stirring, isexactly neutral to test-paper, concentrate to about one-
eighth the original volume, and add excess of concentrated hydro-
chloric acid; impure hippuric acid is deposited. From a solu-
tion of the impure acid in hot water chlorine removes the color,
and the liquid deposits crystals of pure hippuric acid on cooling.
tsts.—To a solution of a hippurate add neutral solution of
ferric chloride; a brown precipitate of ferric hippurate results.
Soluble silver and mercurous salts give white precipitates. Heat
hippuric acid in a test-tube; it chars, benzoic acid sublimes, and
vapors of characteristic odor are evolved; they contain, among
other products, hydrocyanic heid and a substance smelling some-
what like Tonka bean. The crystalline form of hippuric acid is
oe it will be described in connection with the subject
urine,
QUESTIONS AND EXERCISES,
Give the preparation, composition, properties, and tests of benzoic acid,
employing equations.—W hat is the nature of carmine ?—Name the bitter
principle of Iceland “moss."’—How is potassium cyanate prepared, how
converted into an ammonium salt, and what are the relations of the
latter to wrea.—Give the formule of cyanic acid, ammonium cyanate
and urea.—What is the formula of formic acid ?—Describe the artificial
production of formic acid.—What is the relation of formic acid to wood-
spirit —State the sources, characters, and tests of hippuric acid.
Hyprorerrocyansic Actp, H,FeC,N,, or H,Fe(CN),, anv
OTHER FenRocyYANIDEs,—The ferrocyanide of most interest is
326 THE ACID RADICALS.
Potassium Ferrocyanide, Potassium Ferrocyanidum, U. 8. P.,
“yellow prussiate of potash,’’ K,Fe(CN),, 3H,O, the formation
of which was alluded to in connection with hydrocyanic acid
(see p. 266). It cannot be regarded as simply a double salt of
potassium cyanide with ferrous cyanide (4KCN, Fe(CN),), its
chemical properties being entirely different from those of either
of these substances ; moreover unlike potassium cyanide, it is not
poisonous. Most of the reactions point to the conclusion that in
it iron and cyanogen are intimately wnited to form the quadriva-
lent radical appropriately termed Jerroeyanogen (FeO,N,)’”, A
solution of 10 grammes of potassium ferrocyanide in sufficient
water to measure 100 Ce, is the official Potassium Ferrocyanide
Test Solution,
Tests.—Many of the ferrocyanides are insoluble, and are
therefore precipitated when solution of potassium ferrocyanide
is added to the salts of the various metals. The precipitates
produced in solutions of iron and of cupric salts, being of
characteristic color, are adopted as tests for the presence of
these metals or of ferrocyanogen, as the case may be. To a
solution of potassium ferrocyanide add a ferric salt; a dark
blue precipitate of ferric ferrocyanide, Fe, (FeC.N,),”,
Prussian blue, is produced. To another portion add solution
of a cupric salt; a reddish-brown precipitate of cupric ferro-
cyanide, Cu,Fe(CN ), results.
‘ote. —The ferrocyanogen in potassium ferrocyanide is broken
up When the salt is heated with sulphuric acid, carbonie ovide
being evolved if the acid is concentrated (that is, ordinary oil of
vitriol—11S0, with 2 or 8 percent, of water), and Aydroeyanie
acid if dilute:—
K,FeC,N,, 3H,0 + 8H,0 + 8,80, = 4K HSO, 4+ FeSO,
+ 8(NH,),80, 4- 6CO
2K ,FeO,N, +- 6H,SO, = FeK,FeO,N, + 6KHSO,
+ 6HON
Hyprorerricyanic Actp, H,FeC,N,, or H,Fe(CN),, ann
OTHER FERRICYANIDES.—Pass chlorine slowly through asolu-
tion of potassium ferrocyanide until the liquid, after frequent
shaking, ceases to give a blue precipitate when a minute
tion is taken out on the end of a glass rod and brought into
contact with a drop of dilute solution of a ferric salt; it now
contains Potassium Ferricyanide K,Fe(CN),, “red prussiate
of potash,” as it is called from the color of its crystals. Excess
FLUORIDES.
of chlorine must be carefully avoided, as cyanogen chloride
and other compounds are then formed, Such a result does
not ensue if bromine be used instead of chlorine, but this pro-
cess is less economical. |
2K,Fe(CN), + Cl, = 2KCl + 2K,Fe(CN),
Note.—The removal of one-fourth of the potassium from the
ferrocyanide is here accompanied by the conversion of the quad-
rivalent radical ferrocyanogen (FeC,N,)’’’’, into the radical ferri-
eyanogen (FeC.N,)/’’, which is trivalent. Besides by the action
of chlorine, the conversion of potassium ferrocyanide into ferri-
cyanide can be effected by the action of one or other of a variety
of oxidizing agents.
Tests.—To a solution of potassium ferricyanide add solu-
tion of ferrous sulphate ; a dark-blue precipitate is produced.
This precipitate is ferrous ferricyanide (Turnbull’s blue),
Fe,-(FeC,N,),’”.
Sxaag’ Versa’ Foutiuh Tedbnlrt oh
ferricyanide sulphate sulphate
A solution of 1 part of potassium ferricyanide in about 10 of
water forms the official Potassium Ferricyanide Test Solution.
Hyproriuoric Acip, HF, anp orner FLUoRmDEs.—
Hydrofluoric acid is chiefly used for etching glass, The
operation, performed on the small scale, also constitutes the
best test for fluorine, the acid radical of the fluorides.
Experiment and Test. —Coat the convex side of a watch glass
(preferably one made of hard glass) with a layer of beeswax,
by first heating the glass and then rubbing the wax over it.
hen the wax is cold, write through it with the point of a
pin (or other instrument which is not hard enough to scratch
the glass) so as to lay bare some portions of glass, Place a
few grains of powdered fluor-spar (calcium fluoride, Cal’, the
commonest natural fluoride) in a small lead basin (or platmum
crucible), add a few drops of sulphuric acid, cover the basin
with the prepared glass, waxed side downward, and very
gently warm the bottom of the basin in a fume-cupboard in
such a way as not to melt the wax. After a few minutes
remove the glass, wash the waxed side by pouring water over
it, scrape off most of the wax, then warm the glass and wipe
off the remainder ; the glass will be found to be etched at the
| that were laid bare by the removal of the wax, The
ydrofluoric acid liberated by the action of sulphuric acid on
328 THE ACID RADICALS.
the fluor-spar has eaten into or etehed (from the German
fitzen, to corrode) the glass.
The calcium fluoride and sulphuric acid yield hydrofluoric acid,
thus :—CaF, + H,SO,= CaSO,+ 2HF. The hydrofluoric acid
gas and the silica of the glass then yield silicic and flurosilicic acids
and water, thus :—
HF + 3ssi0, = HSO, + 2H SiF, + 2H,0
Hydrofiuorie Silica silicic Fluositicle Water
Hat re |
The silica being removed from the glass, leaves furrows or etched
portions,
The aqueous solution of hydrofluoric acid, used by etchers, and
commonly termed simply hydrofluoric acid, or ‘‘fluorie’’ acid, is
prepared in leaden stills and receivers, and kept in leaden or gutta-
percha bottles, Hydrofluoric acid rapidly attacks any substance
of which bottles and basins are usually made except lead and
gutta-percha. It is also without action on platinum and fluor-
spar. It quickly cauterizes the skin, producing a painful, slow-
healing sore, A mixture of hydrofluoric acid and ammonium
fluoride, known as ‘‘white acid,’’ is also used for etching glass.
Experiments by Meslans show that anhydrous hydrogen fluor-
ide has no action on absolute alcohol below 266° F, (180° Hos
Above that temperature interaction takes place; and at 410° to
428° F, (210° to 220° C.) about 35 percent. of the gas is esterified
in three hours, and gaseous ethyl] fluoride may be collected.
Quantivalence. —Fluorine, like chlorine, bromine, and iodine,
is wnivalent (F’),
Huorine has been isolated by electrolyzing hydrofluoric acid. Tt
is a greenish-yellow gas with an irritating odor, It combines
with great readiness with all elements exceptoxygen. By cooling
and compressing the gas, Moissan and Dewar have obtained fluo-
rine as a pale-yellowish liquid.
Hypopnospnorovs Acrp, H,PO, or HPH,O, AND ornEr
Hyrornosprires.—Boil together i in a fume-cupboard, two or
three grains of phosphorus, three or four grains of caleium
hydroxide, and about a quarter of an ounce of water, until
hydrogen phosphides are no longer evolved. The volatile
products of the interaction are trihydrogen phosphide (or
phosphuretted hydrogen), PH,, and a small quantity of the
vapor of a liquid phosphide, P,H,. The vapor of the latter
ignites spontaneously in contact with air, and imparts to the
gaseous mixture the property of spontaneous inflammabili
The calcium hydroxide must not be in great excess, or the
hypophosphite produced by the interaction will be converted
HY POPHOSPHITES. 329
into phosphate as fast as formed. The mixture, filtered, and
excess of lime removed by means of carbonic anhydride, yields
a solution of calcium hypophosphite, Ca(PH,O,), ( Caleii
Hypophosphis, U.S. P.). The salt may be obtained in crys-
tals hy evaporation and slow cooling.
2P, + 6H,O + 8Ca(OH), = 8Ca(PH,O,), + 2PH,
Trihydrogen phosphide or phoephuretted hydrogen, PV,.—The
above reaction is the one by which phosphuretted hydrogen is
usually prepared, If the gas is to be collected, the phosphorus
and water may first be boiled in a flask until ajet of spontaneously
inflammable phosphorus vapor escapes with steam, from the end
of the attached delivery-tube. Hot concentrated solution of potas-
sium hydroxide or sodium hydroxide is next very gradually poured
into the flask through a funnel-tube previously fitted into the cork,
the liquid being kept boiling. Potassium or sodium hypophosphite
is formed in solution, while phosphuretted hydrogen is evolved, and
if the delivery-tube dip under water may be collected, or allowed to
slowly pass up through the water, bubble by bubble, so as to burst
into flame spontaneously and form vortex rings of white smoke
which arise one after the other into the air and are characteristic
of the experiment. A solid hydrogen phosphide, P,H,, is known.
Sodium Hypophosphite, NaPH,O,, H,O (Sodiit Hypophoaphis,
U. 8. P.) is made by the interaction of solutions of calcium hypo-
phosphite and sodium carbonate, filtering and evaporating to dry-
ness. Ca(PH,O,), + Na,CO,= 2NaPH,O, 4+ CaCO, It is a
white, granular, deliquescent substance. When heated, the water
ia first evolved, then hydrogen and hydrogen phosphide, and a
mixture of sodium pyrophosphate and metaphosphate remains,
5NaPH,O, = Na,P,O, + NaPO, + 2PH,+ 2H,, (Rammelsberg. )
Acid, hydrogen hypophosphite (Acidum Hypo-
hosphorosum, U.S. P.), may be prepared by decomposing the
calcium salt by means of oxalic acid, or better, the barium salt
by means of sulphuric acid.
Acidum Hypophoephorosum Dilutum is also official.
Ferri Hypophosphis, Fe(PH,O,),, Mangani Hypophosphia,
Mn (PH,O,),, and Potaasii Hypophosphis, KPH,O,, are included
in the Pharmacopaia.
_ Quinine hypophosphite, is prepared by dissolving quinine in
hypophosphorous acid, or by decomposing quinine sulphate by
means of barium hypophosphite. The latter is obtained on boil-
ing excess of pure barium hydroxide with ammonium hypophos-
until all the ammonia has been evolved. The ammonium
salt is formed on bringing calcium hypophosphite and ammonium
together in presence of a little ammonia, 0%
The hypophosphites are often used in medicine in the form of
syrups ( Hypophosphitum, U. 8. P.; Syrupus Hypophos-
430 THE ACID RADICALS,
phitum Compositus, U.S, P.). The term hypophosphite is used in
connection with these salts on account of their containing asmaller
proportion (ird, Aupo, under) of oxygen than the age 3 (a
class of salts which, in turn, contain less oxygen than the phos-
phates). The prefix Aypo has similar significance in such words
as hyposulphite and hypochlorite.
Tests.—To a solution of calcium or sodium hypophosphite
add solution of barium chloride, calcium chloride, or lead
acetate; in neither case is a precipitate obtained, whereas
soluble phosphates and phosphites yield white precipitates
(of barium, calcium, or lead phosphate or phosphite). To
other portions of a hypophosphite solution add solutions of
silver nitrate and mercuric chloride; precipitates of metallic
silver in the one ease and of mercurous chloride and then
of metallic mercury in the other are produced, (Similar
reactions are produced by phosphites.) To another small
portion add zine and dilute sulphurie acid; hydrogen and
hydrogen phosphide are evolved (as from phosphites). Toa
solution of calcium hypophosphite add sufficient oxalic acid to
remove the calcium ; filter; to the solution of hypophosphorous
acid so obtained add solution of cupric sulphate and slowly
warm the mixture; a brown precipitate of cuprous hydride,
Cu,H,, 1s produced: heat to the hoiling-point ; hydrogen is
evolved and metallic copper is set free. Add a solution of a
hypophosphite to a mixture of aqueous solution of ammonitim
molybdate with solution of sulphurous acid; a blue preeipi-
tate results, or in dilute solutions, a blue color which deepens
on standing. Heat a small quantity of a solid hypophosphite
on the end of a spatula in a flame, and note the odor of phos-
phuretted hydrogen and the combustion of this gas. The salt
breaks up into pyrophosphate, some metaphosphate, hydrogen,
hydrogen phosphide, and water, the official caleium hypophos-
phite yielding about 80 percent. of residue.
7Ca(PH,O,), =3Ca,P,0, +-Ca(PO,), + 6PH, +H,O-+ 4H,
Five grains of calcium hypophosphite, if of good quality,
will almost decolorize a solution of not less than twelve grains
of potassium permanganate, on boiling the mixture for about
ten minutes. Five grains of sodium hypophosphite should
almost decolorize not less than eleven and a half grains of
permanganate under similar conditions,
LACTATES. 3a1
Potassium permanganate, in acid solution, is also reduced
by the solution of a phosphite but not by that of an ortho-,
meta-, or pyro-phosphate.
QUESTIONS AND EXERCISES.
Give the formula of potassinm ferrocyanide.—Enumerate the tests for
ferro n,—What are the respective reactions of potassium ferro-
Ne with concentrated and dilute sulphuric acid ?—Write equations
illustrative of the changes effected in potassium ferrocyanide during its
conversion into ferricyanide.—By what reactions may the presence of #
ferricyanide in a solution be demonstrated ?—State the difference between
Prussian blue and Turnbull's blue.—Describe thesource, mode of prepara-
tion, chief use of, and test for hydrofluoric acid —What compounds are
produced by boiling phosphorus in solution of alkalies ?—Give equations.
—How is trihydrogen phosphide prepared ?
Lactic Acip, HC,H,O,, anp orner Lacrarrs,—Lactic
acid occurs in willow bark (Dott). When milk turns sour,
some of its sugar has become conyeried by the bacillus acidi
lactici, fed by the nitrogenous matter, into lactic acid (lae,
laetia). Other saccharine and amylaceous substances also
yield lactic acid by fermentation. Neither hydrogen lactate
(lactic acid) nor other lactates are much used in Great Britain.
tion,—Calcium lactate and lactic acid may be
as follows :—Mix together eight parts of sugar, one
of cheese, three of chalk, and fifty of water, and set aside in
a warm place (about 80° F.) for two or three weeks ; a mass
of small crystals of calcium lactate results. Remove these,
reerystallize from hot water, decompose by means of sulphuric
acid (avoiding excess), digest in alcohol, filter off the calcium
sulphate, evaporate the clear solution to a syrup; this residue
is ny lactic acid (Acidum Lactieum, U.S, P.), sp. gr.
1,206,
A syrup of calcium lactophosphate is official (Syrupua Calcii
: WO is, U. 8. P.).
Test.—No single reaction of lactic acid is sufficiently distinctive
to be regarded as a test, The crystalline form of calcium lactate,
as seen under the microscope, is characteristic. The production
of this salt, and the isolation of the syrupy acid itself, are the only
means of identification, short of quantitative analysis, on which
reliance can be placed. Lactic acid is soluble in water, alcohol,
332 THE ACID RADICALS,
and ether, but almost insoluble in chloroform, It is only slightly
colored by cold sulphuric acid. Warmed with potassium perman-
ganate, it gives the odor of aldehyde,
A variety of lactic acid has been obtained from the juice of flesh ;
it is termed sarcolactic acid (from caps, capxdc, sarc, sarcos, flesh),
Unlike lactic acid, it yields a precipitate with solution of cupric
sulphate,
Manic Acrp, C,H,O,, AND OTHER MALATEs (from malwm, an
apple).—The juices of unripe apples, gooseberries, currants, straw-
berries, grapes, and of rhubarb-stalks, ete., contain malic acid
and potassium malate, When isolated, malic acid forms deliques-
cent prismatic crystals,
Tests, —Calcium malate, CaC,H,O,, is soluble in water, hence the
aqueous solution of malic acid or other malate is not precipitated
by lime-water or calcium chloride ; but, on adding alcohol, a white
precipitate is produced, owing to the insolubility of calcium mal-
ate in that liquid. Malates are precipitated by lead salts; on
warming the precipitate of lead malate with acetic acid it dissolves,
separating out in acicular crystals on cooling. If the mixture be
heated in absence of the acid, the precipitate agglutinates and fuses,
Hot concentrated sulphuric acid chars malic acid far leas readily
than it does nearly all other organic acids.
Asparagin (C,H.N,O,, H,O).—This proximate principle of plants
occurs in many vegetable juices, and doubtless plays a very impor-
tant part in their nutrition. It is deposited in crystals when the
fresh juices of asparagus, marsh-mallow, etc., are rapidly evapor-
ated. It is noticed here because malic acid is readily obtained
from it by oxidation, nitrogen being eliminated, When its solu-
tion is long boiled it is converted into ammonium aspartate,
NH,C\H,.NO,. Decomposed by aid of ferments, asparagin, absorb-
ing hydrogen, yields ammonium succinate, (NH,),C,H,O,.
Mecontc Acrp, H,C,H,0,, 3H,0.—Opium contains meconie
acid (from pajzwv, mekon, a poppy) partially combined with
morphine. To concentrated infusion of opium, nearly neutral-
ized with ammonia, add solution of calcium chloride; erude
calcium meconate is precipitated. Wash the precipitate, place
it in a small quantity of hot water; add a little hydrochlorie
acid ; the clear liquid (filtered, if necessary ) deposits scales of
impure meconic acid on cooling.
Tests.—T'o a solution of meconic acid or other meconate (or
to infusion of opium) add a neutral solution of ferrie chloride ;
a red solution of ferric meconate is produced. To a portion
of the mixture add solution of corrosive sublimate; the red
color is not destroyed: to another portion add hydrochlorie
acid ; the color is discharged. (These reagents act on ferric
METAPHOSPHATES. 333
thiocyanate, which is of similar tint, with exactly the opposite
results.) To another portion add a drop of a dilute acid, and
boil ; the color is not discharged. (A solution of ferric ace-
tate, which is of similar color, 1s decomposed on boiling, giving
a colorless fluid and a red precipitate—ferric oxyacetate, )
The normal potassium, sodium, and ammonium meconates are
soluble in water, the acid meconates very slightly soluble ; the bar-
ium, calcium, lead, copper, and silver meconates are insoluble in
water, but soluble in acetic acid.
MerarnosrHoric Actp, HPO, AND oTHER METAPHOs-
puatTEs.—Prepare phosphoric anhydride, P,O,, by burning a
small piece of phosphorus in a porcelain crucible placed on a
plate and covered by an inverted test-glass, large beaker, or
some such vessel. After waiting a few minutes for the phos-
horic anhydride to fall, pour a little water on the plate and
Iter the liquid; the product is a solution of metaphosphoric
acid ; P.O, 4+- H,O = 2HPO,,
Tests.—To a solution of metaphosphoric acid add silver
ammonio-nitrate, or to a neutral metaphosphate add solution
of silver nitrate ; a white precipitate of silver metaphosphate,
AgPO,, is obtained. This reaction sufficiently distinguishes
metaphosphates from the ordinary phosphates or orthophos-
phates (from pds, orthos, straight ), as the common phosphates
may, for distinction, be termed (which give, it will be remem-
bered, a yellow precipitate with silver nitrate). Another set
of salts shortly to be considered, the pyrophosphates, also give
a white precipitate with silver nitrate. To the solution of
metaphosphoric acid obtained as above or by the action of
acetic acid on a metaphosphate, add an aqueous solution of
white of egg; coagulation of the albumen ensues. Neither
orthophosphorie nor pyrophosphoric acid coagulates albumen.
Boil the aqueous solution of metaphosphoric acid for some
time ; on testing the solution, the acid will be found to have
been converted into orthophosphorie acid ;—
HPO, + H,O = H,PO, (orthophosphorie acid),
The ordinary medicinal phosphoric acid is made from phos-
phorus and nitric acid, the liquid being evaporated to a syrupy
consistence (or treated as described on ». 315) to remove the last
traces of nitric acid. It may contain pyrophosphoric and meta-
phosphoric acids if the temperature employed be high enough to
remove the elements of water :—
THE ACID RADICALS.
2H,PO, - H,O = H,P,0, (pyrophosphoric acid),
H,PO, - H,O = HPO, (metaphosphorie acid).
On redilution the metaphosphoric acid only slowly reabsorbs
water. If, therefore, on testing the diluted solution metaphos-
phoric acid be found to be present, the solution should be boiled
until conversion into orthophosphoric acid is complete.
Nrrrovs Actp, HNO,, anp orHEeR Nirrrres.—dStrongly
heat a fragment of potassium or sodium nitrate on a piece of
platinum foil; oxygen is evolved, and impure potassium or
sodium nitrate remains,
Tests.— Dissolve the residue in water, add a few drops of
dilute sulphuric acid, then some dilute solution of potassium
iodide, and, lastly, some starch mucilage ; the deep-blue “stareh
iodide” is produced. 2HI -+- 2HNO, = 2H,O-+ 2NO+ 1
Repeat this experiment, using potassium nitrate instead of
nitrite ; no blue color is produced. To a solution of a nitrite
add solution of ferrous sulphate; a brown coloration is pro-
duced. Dissolve a small quantity of a nitrite in concentrated
sulphuric acid, and add a few particles of cuprous oxide ; an
intense violet purple color is produced.
Tests for Nitrites in. Water.—The liberation of iodine from potas-
sium iodide in acid solution by nitrites and not by nitrates is a
reaction of considerable value in searching for nitrites in ordinary
drinking waters, the occurrence of such salts, except in very deep-
seated springs being held to indicate the presence of nitrogenous
organic matter in a state of oxidation or decay. The sulphuric
acid used in the operation must be pure, and the potassium iodide
free from iodate. If much organic matter is present, however,
the nitric acid liberated by the sulphuric acid may be reduce
to nitrous acid. It is perhaps best, therefore, to add acetic acid,
and distil over 10 or 20 percent. of the water, and apply the test
to this distillate (Fresenius). Very dilute solutions of nitrous acid
may thus be distilled without the slightest decomposition.
Sodium Nitrite, NaNO, (Sodii Nitris, U. 8. P.). This salt
yields ruddy nitrous fumes on the addition of sulphuric acid.
When dissolved in water and tested in a nitrometer, with potaa-
sium iodide and dilute sulphuric acid, it should liberate a quan-
tity of nitric oxide, corresponding to not less than 90 percent, of
sodium nitrite.
Other nitrates used in medicine are nitrites of organic radicals,
Ethyl nitrite, C,H,NO,, or nitrous ether, is the most important
constituent of Spiritus Aitheris Nitrosi, U. 8. P. Amyl nitrite,
©, H,,NO,, is also official (Amylis Nitris, U, 8, P.),
Ammonium nitrite, on being heated, yields pure nitrogen :—
NH,NO, = 2H,0 + N,. : se '
PHOSPHOROUS ACID. — 885
Determination of nitrous acid in commercial sulphuric acid
(Lunge and Swofl’s method). 1 Cc. of Griess’s reagent is put
into each of a pair of Nesslerizing tubes and mixed with 40 Cc.
of water and 5 grammes of sodium acetate. To the contents of
the first tube 1 Cc. of the suspected acid is added, and to the
other, without delay, 1 Ce, of a standard nitrite solution prepared
by dissolving 0.0493 gramme of pure sodium nitrite in 100 Ce. of
water and diluting 10 Cc. of this to 100 Ce. with pure sulphuric
acid. The reddish colors may be compared after any convenient
time, but it is best to wait five minutes. Griess’s reagent may be
ah ees as follows :—0.1 gramme of white a-naphthylamine is
iled for fifteen minutes with 100 Cc. of water and mixed with
5 Ce. of glacial acetic acid. The solution is then mixed with 1
gramme of sulphanilic acid dissolved in 100 Ce. of water, and the
mixture preserved in a well-corked bottle. If it should become
too red, it may be decolorized by shaking it with zine dust.
Note,—a-Naphthylamine, C,,H,NH,, is obtained when a-naph-
thol is heated for some time either with saturated aqueous ammo-
nia, or with ammonium chloride and caustic alkali under pressure,
or by the reduction of nitro-naphthalene, Su/phanitlie acid,
C,H, 80,H.NH,, is prepared by heating a mixture of aniline and
sulphuric acid containing some pyrosulphuric acid to a tempera-
ture of 180° C. for several hours, and pouring into water, when
the acid is precipitated in a crystalline form.
Opne.ic Actp, C,,H,,0,,.—This is one of the principles to
which the herb Swertia chirayita, or Chiretta ( Chirata,
U. & P.), owes its bitterness. It is an amorphous yellow
substance. Another is Chiratin, C,H,.O,., decomposable by
hydrochloric acid into Chiratogenin, C,,H,,O,, and ophelie
acid (Hohn).
Puosruorovus Acip, H,PO, or H,PHO,,—A solution con-
taining this acid in small quantity could be obtained by
permitting the heavy white fumes which fall from a stick of
moist phosphorus on exposure to the air to dissolve in some
water placed at the bottom of a wide-mouthed bottle. Or
osphorous oxide, P,O,, may first be obtained by gently
eating phosphorus in a tube, through which a slow current
of air is drawn, condensing the fumes in a U-tube surrounded
a freezing mixture, and then decomposing the oxide by
the action of water :—P,O, 4+ 6H,O —4H,PO,. Or chlor-
ine is through phosphorus melted under water :—
PCI, + 3H,O —=H,PO,+3HCl. Having collected some
phosphorous acid, apply the various tests already alluded to
under Hypophosphorous Acid, first carefully neutralizing the
phosphorous acid with « caustic alkali.
THE ACID RADICALS.
The soluble phosphites are prepared by neutralizing phos-
phorous acid with the appropriate alkalies, and the insoluble
phosphites by double decomposition.
Associated with phosphorous acid prepared as above stated
there is said to be an acid of the formula H,PO,, termed hypophos-
phorie acid,
PyroGa.Liic Acitp,—See TANnic Actp.
Pyrornosrpnoric Acitp, H,P.O,, AND OTHER PyROPHOs-
PHATES. — Heat ordinary soci phosphate, Na, HPO,,
12H,O, in a erucible ; water of crystallization is first evolved,
ancl anhydrous phosphate, Na,HPO,, remains. Further heat
to redness ; water is again ev olved and a new salt is obtained ;
—2Na, HPO, =H,O + Na,P,0.. The latter is termed
sodium py rophosphate, in allusion to its origin (xdp, pir,
fire). From its solution in water it may be obtained in
prismatic crystals, Na,P,O, 10H,O. Phosphoric acid itself
is similarly affected by heat, yielding pyrophosphoric acid :-—
2H,PO, = H,O 4+ H,P,0,, though metaphosphorie acid is
also formed. Other pyrophosphates are produced similarly,
or by double decomposition and precipitation, or by neutraliz-
ing pyrophosphorie acid with an oxide, hydroxide, or carbon-
ate. Ferri Pyrophosphas Solubilis, and Sodii Pyrophosphas,
Na,P,O,, 10H,0, are official.
Teats.—To a solution of a pyrophosphate add solution of
silver nitrate; a dense white precipitate of silver pyrophos-
phate, Ag, P.O, is produced, differing much in appearance
from the white gelatinous silver metaphosphate or the yellow
orthophosphate. To pyrophosphoric acid, or to a pyrophos-
phate mixed with acetic acid, add an aqueous solution of
albumen (white of egg) ; no precipitate is formed. Metaphos-
phoric acid, it will be remembered, gives a white precipitate
with albumen. Both pyro- and meta-phosphoric acids give
precipitates on adding Tincture of Ferrie Chloride,
ACIDS OF PHOSPHORUS,
The following acids of phosphorus have now been
described :—
{ Irthophosphorice acid, H, PO,
Pyrophosphorie acid, H. P, 0,
Metaphosphoric acid, HPO,
Phosphorous acid, H PO
Hypophosphorous acid, H., PO,
SILICATES, 337
The three phosphoric acids (ortho-, pyro-, and meta-) corre-
spond to the higher oxide of phosphorus, P,O,, while phosphor-
ous acid corresponds to the lower oxide, P,O,. Pyrophosphoric
and metaphosphoric acids may be obtained from the ordinary or
orthophosphorie acid by the removal of water. Hypophosphorous
acid corresponds to a still lower (hypothetical) oxide of phos-
phorus than P,O, Although three hydrogen atoms are repre-
sented in the formule of both phosphorous and hypophosphorous
acids, the acids behave as dibasic and as monobasic respectively.
QUESTIONS AND EXERCISES.
What are the sources of lactic acid ?—How is lactic acid usually pre-
pared ?—Name some of the plantsin which malic acid is found.—Whence
is meconic acid derived ?—By what process may meconic acid be isolated?
—Which is the best test for the meconic radical ?—How may meconates
be distinguished from thiocyanates ?—By what ready method may meta-
hosphoric acid be obtained for experimental purposes ?—Name the tests
or metaphosphates—How may meta- or pyrophosphoric acid be con-
verted into orthophosphoric acid ?—Describe the preparation of phosphor-
ous acid.—How are the pyrophosphates prepared ?—Give formule
illustrative of metaphosphates, pyrophosphates, orthophosphates, phos-
phites, ond hypophosphites.—Mention the tests by which meta-, pyro-,
and orthophosphates are analytically distinguished.—How are hypo-
phosphates and phosphites detected ?
Sriicic Act, HSi0, AND OTHER SrLicatTes,—Silicates of
various kinds are among the commonest of minerals. The
yarious e/ays are more or less impure aluminium silicates ; the
volcanic substance termed pumice-stone is a porous aluminium,
alkali-metal, and alkaline-earth-metal silicate; the varieties of
felspar as a rule contain aluminium and alkali-metal silicates or
aluminium and alkaline-earth-metal silicates ; meerschaum is an
acid magnesium silicate ; the ordinary sandstones are chiefly silica ;
sand, flint, quartz, agate, chalcedony, and opal are silicic anhydride
or silica, SiO,. Tripoli powder, a polishing powder now found in
many other countries than Tripoli, and consisting of infusorial
skeletons, is nearly pure silica. Bath brick is a silico-caleareous
deposit found in the estuary at Bridgwater, England, and other
places. Tburmalines, plates of which, cut parallel to the axis of
a crystal, are used as polarizers or analyzers in microscopy, are all
aluminium silicates with varying proportions of iron, copper,
Manganese, or other silicates, Asbestos or amianth is a fibrous
calcium and magnesium silicate, the length of the fibres varying
from leas than one inch to five feet. A single silk-like fibre can
easily be fused, buteven in very small masses, asbestos is infusible
in the Bunsen flame, and is incombustible. It is also a bad con-
ductor of heat. It is largely used in packing piston rods and
22
338 THE ACID RADICALS.
joints, and for steam apparatus generally ; as a covering for boilers
to prevent loss of heat by radiation ; and for so lining ceilings,
floors, and other partitions as to render rooms, etc., fireproof.
Artificial acid insoluble silicates are familiar in the form of glass
and earthenware. Common window-glass (crown glass) is usually
calcium, sodium, and aluminium silicate ; French glass, calcium
and sodium silicate; Bohemian glass, chiefly potassium and
calcium silicate ; flint or crystal-glass for ornamental, table, and
optical purposes, is mainly potassium and lead silicate. Earthen-
ware is mostly aluminium silicate (clay), with more or less of the
easily fusible silicates, namely, those of calcium, sodium, and
potassium, and in the commoner forms, iron silicate, The
various kinds of porcelain (China, Sévres, Meissen, Berlin,
English), Wedgwood-ware, and stoneware are yarieties of earthen-
ware. Kaolin, or Chinaclay, which is disintegrated /felspar, is
the clay which yields the finest translucent porcelain. When
powdered and freed from gritty particles by elutriation, it is
official (Kaolinum, U. S. P.). Crucibles, brieks, and tiles are
made from different varieties of clay. /ireclay contains excess of
silica and very small proportions of the fusible silicates, hence its
refractory character. Mortar, if old, contains a little calcium
silicate, but its binding action is due to the soft slaked lime
penetrating the minute cavities on the surfaces of adjacent bricks
and stones, and then becoming converted into an interlacing or
‘‘keying’’ mass of hard particles of calcium carbonate. The
admixed sand which mortar contains, renders the mass porous and
so far promotes absorption of carbonic anhydride from the atmos-
phere, but its proportion should not much exceed two measures
to one measure of lime, or, by weight, three of sand to one of
good lime. Portland, Roman, and other ‘‘hydraulic’’ cements are
calcium silicates with more or Jess aluminium silicate. uller’s
earth (fullones, cleansers of cloth) is chiefly silica, but contains
combined calcium, magnesium, aluminium, and iron, with a
smal! quantity of potassium, Like the Arab’s ¢/o/, another earth
containing gelatinous silica, Fuller's earth is a powerful absorbent
of oils and fats, -
Experiment.—Mix a few grains of powdered flint or sand
with about five or six times its weight of sodium carbonate
and an equal quantity of potassium carbonate, and fuse a
little of the mixture on platinum foil in the blow-pipe flame ;
the product is a soluble alkali-metal silicate, a soluble glassor
water glass. Boil the foil in water, for a few minutes ; filter;
to a portion of the filtrate add excess of hydrochloric acid,
evaporate the solution to dryness, and again boil the residue
in dilute acid ; silicon oxide, silicic anhydride, or siliea, SiO,
remains as a light, flaky, insoluble powder,
SILICATES. 339
The foregoing operation constitutes the fest for silicates. By
fusion with alkali the silicate is decomposed, and a soluble alkali-
metal silicate formed. On addition of acid, silicic acid, H,SiO,,
is set free, but remains dissolved if the solution is not too concen-
trated, The heat subsequently applied eliminates water and con-
verts the silicic acid into silica, SiO,, which is insoluble in water
or hydrochloric acid.
The soluble glass, water glass, or glass liquor of trade may be
prepared by fusion, as above; or by boiling up infusorial earth
with solution of sodium hydroxide in closed vessels under a pres-
sure of 7 or 8 atmospheres (the proportions of sodium hydroxide,
silica, and water in the latter case being about 1, 2, and 5 respect-
ively),
By the addition of hydrochloric acid to soluble glass, and the
removal of the resulting alkali-metal chloride and excess of hydro-
chloric acid by dialysis (a process to be subsequently described), a
pure aqueous solution of silicic acid may be obtained ; it readily
changes into a gelatinous mass of silicic acid. Possibly some of
the natural crystallized varieties of silica may have been obtained
from the silicic acid contained in such an aqueous solution, nearly
all natural waters yielding a small quantity of silica when evapo-
rated to dryness with hydrochloric acid.
A variety of silicie acid, HSiO,, sometimes termed dibasic to
distinguish it from the fefrabasic acid, H,SiO,, results when the
aqueous solution of the latter is evaporated in vacuo. Various
nuitural silicates correspond to this acid.
Silicon hydride, or siliciuretted hydrogen, Sil,, is a spontaneously
inflammable gas formed on treating magnesium silicide with hydro-
ehlorie acid. It is the analogue of marsh gas or methane, CH,.
A liquid silicon chloride, SiC) y Analogous to carbon tetrachloride,
OCI,, and a gaseous fluoride, SiF, are also known, The latter is
formed when sulphuric acid acts on a mixture of a fluoride with
silica or a silicate, It interacts with water with the production of
silicic and fluosilicic acids (see p, 828). A carbon silicide, CSi,
known as carborundum, is formed when carbon and silicon are
heated together in an electric furnace.
Many other analogies are traceable between the elements silicon
and carbon, especially among their organic compounds.
Svecinic Actp, H,C,H,O,.—Amber (Succinum) isa resin usually
occurring in association with coal and lignite. From the fact that
fragments of coniferous fruit are frequently found in amber, and
impressions of bark on its surface, it is considered to have been
an exudation from a species of Pinus now probably extinct. Heated
in a retort, amber yields, first, a sour aqueous liquid containing
acetic acid and succinic acid ; secondly, a volatile liquid known as
oi! of amber, resembling the oil yielded by most resinous substances
under similar circumstances ; and, thirdly, a pitchy residue allied
to asphalt. The succinic acid is a normal constituent of the amber,
THE ACID RADICALS.
the acetic acid is produced during distillation. Succinic acid has
also been found in wormwood, in several pine-resins, and in certain
animal fluids, such as those of hydatid cysts and hydrocele. It is
a product of the vital activity of various micro-organisms, and can
be formed by these from carbohydrates, from substances allied to
carbohydrates, and from albumin. It may be obtained artificially
from butyric or stearic acid by oxidation ; and from tartaric and
malic acids by reduction,
Both normal and acid succinates, R’,C,H,O, and RYHC,H,O,, are
known. A potassium hydrogen succinate, Kric ,H,0 H, dat H,O,,
H,O, analogous to salt of sorrel, also exists. Soluble succinates
give a bulky brown precipitate with neutral ferric chlorine (some-
what less voluminous than ferric benzoate) ; a white precipitate
with lead acetate, soluble in excess of either reagent; with silver
nitrate a white precipitate after a time; with barium chloride no
precipitate at first, but a white precipitate of barium succinate on
the addition of ammoniaand alcohol, Succinates are distinguished
from benzoates by the last named reaction, and not by yielding a
precipitate on the addition of acids (see p. 323).
Tannic Actp, GALLoTANNIC Acip, oR Tannin. Digallie
acid, C,,H,,0,, 2H,O.—This is a very common astringent constit-
uent of: plants, but is contained in largest quantity in galls (excres-
cences on the oak, formed by the puncture and deposited ova of an
insect). English galls contain from 14 to 28 percent, and Aleppo
galls (Galla, U. 8. P.) 25 to 65 percent, of tannic acid (Acidum
Tannicum, U. 5. P.).
Mm yrobalans, the dried immature fruits of Terminalia
the ‘‘Chebulic myrobalans’’ of commerce, may be used in India
and the Eastern Colonies instead of galls, The best contain about
30 percent, of tannin,
Gallotannic acid...C,H,(OH),CO,0.C,H,(OH),COOH
Gallic acid (p. 348)...0,H,(OH),COOH
Preparation.— Expose powdered galls (about an ounce is
sufficient for the experiment) to a damp atmosphere for two
or three days, and afterward add sufficient ether to es a
soft paste. Let this stand in a well-closed vessel for twen
four hours, then having quickly enveloped it in a linen el
submit it to strong pressure, so as to separate the liquid portion
which contains the bulk of the tannic acid insolution
the pressed cake to powder, mix it with sufficient ether (to
which one-sixteenth of its bulk of water has heen added) to
form again a soft paste, and press this as before. Mix the
expressed liquids, and expose the mixture first to spontaneous
evaporation and next to gentle heat until it has aequired the
consistence of a soft extract ; then place it on earthen plates or
TANNATES, 541
dishes, and dry it in a hot-air chamber at a temperature not
exceeding 212° F, (100° C.).
The resulting tannic acid is a light brownish powder con-
sisting of thin glistening scales, with a characteristic odor, a
strongly astringent taste, and an acid reaction; readily soluble
in water, and alcohol (90 percent. ), very sparingly soluble in
pure ether though soluble in the ethereal fluid used in the
foregoing process (a mixture of ether, water, and aleohol—
the latter contained as impurity in the ether. )
The official preparations of tannic acid are Glyceritum Acidi
Tannici, Unguentum <Acidi Tannici, and Trochisei Acidi
Tannici. Tannic Acid Test Solution contains 1 part of Tan-
nic acid in 1 part of alcohol and sufficient water to measure
10 parts,
Reactions of Tannie Acid.
1. To an aqueous solution of tannic acid add aqueous solu-
hon of gelatin ; a yellowish-white flocculent compound of the
two substances is precipitated.
The above reaction also serves to explain the chemical principle
involved in fanning—the operation of converting skin into leather,
In this process the skin is soaked in infusion of oak-bark, the tan-
nic acid of which, uniting with the gelatinous tissues of the skin,
yields a compound very well represented by the above precipitate,
The outer bark of the oak contains little or no tannic acid, and is
commonly shaved off from the pieces of bark which are large
enough to handle; useless coloring matter is. thus also rejected,
Other infusions and extracts besides that of oak-bark (chiefly cate-
chu, sumach, and valonia) are largely used by tanners; if used
alone, these act too quickly, and give a harsh, hard, less durable
leather, The tannic acid of these preparations is slightly different
from that of oak-bark.
2. To an aqueous solution of tannic acid add aneutral solu-
tion of a ferric salt; dark bluish-black ferric tannate is slowly
precipitated. This is an excellent test for the presence of
tannic acid in yegetable infusions. The precipitate is the
basis of nearly all black writing-ink, Ferrous salts give al
first only a slight reaction with tannic acid; but the liquid
gradually darkens: characters written with a liquid of this
kind, of proper strength, become quite black in a few hours,
and are yery permanent.
342 THE ACID RADICALS,
3. To an aqueous solution of tannic acid add solution of
tartar-emetic ; antimony tannate is precipitated. This reaction
and that with gelatin are useful in the quantitative determina-
tion of tannic acid in various substances, the separation of the
gelatin tannate being much promoted by previously adding
some heavy neutral powder, such as barium sulphate, and
well stirring while adding the gelatin.
The variety of tannic acid which occurs in oak-bark is said to
be a glucoside; that is, like many other substances, it yields glu-
wose (grape-sugar) when boiled with dilute sulphuric or hydro-
chloric acid, the other product being gallic acid,
Gambir U. 8. P., an extract of owrouparia Gambir ; us well as
the true (or black) Catechu, Cutch, or Terra Japonica, an extract
from Acacia Catechu and A, Sumah; the original African (Gambian)
Kino, termed by the Mandingo natives Kano, from Pterocarpus
erinaceus, but not now in commerce; Last Indian Kino (Kino,
U. 8. P.), from the Pterocarpus marsupium ; also Bengal or Butea
Kino, from the Palas or Dhak tree, Butea frondosa; Botany Bay
or Australian Kinos from various species of Eucalyptus or Blue
Gum trees and some other vegetable products—contain a variety
_ of tannic acid (mimotannic acid), which gives a greenish precipi-
wate with neutral solutions of ferric salts. According to Paul and
Kingzett this acid yields, when decomposed, unfermentable sugar,
and an acid different from ordinary gallic acid. Cateechu and
Gambier also contain cafechwie acid or catechin, C,,H,O,, a com-
pound oceurring in minute colorless acicular ery and, like
mimotannic acid, affording a green precipitate with ferric salts.
The rind of the fruit of the pomegranate (Punica granatum)
(Granatum, U.S. P.) contains tannic acid. The astringency of
Pomegranate-root -Bark is due to a tannic acid (its anthelmintic
properties probably to a resinoid matter, or possibly to what
Tanret states to be a liquid alkaloid). A tannic acid also proh-
ably gives the astringency to logwood (/fa@matoxrylon U, 8. P-).
Rhatany-root Bark (Krameria, U. 8. P.) contains about 20 percent,
of tannic acid, its active astringent principle ; rhubarb-root about
9 percent. Bearberry leaves ( Uv: Ursi, U, 8. P.) owe most of
their therapeutic power to about 35 percent, of tannic acid.
cause of their influence on the kidneys is not yet traced,) They
also contain arbufin, a crystalline glucoside. Larch Bark, the
inner bark of Pinus Larix or Larix Europea, contains, according
to Stenhouse, a considerable amount of a tannic acid giving olive-
green precipitates with ferric salts, and /arivin and larixvinée acid,
O,,H,0,, & somewhat bitter substance, Areca nuts or Betel nuta,
from the Areca Palm (Areea Cotechu), besides the alkaloid arehane
(Bombelon), contain a very active alkaloid, arecotine, O,H,NO,
(Jahns), said to be the vermifugal principle; areeaine, an inert
TANNATES,
alkaloid (Jahns), and according to Fliickiger and Hanbury, about
16 percent. of ‘‘tannic matter.’’ Sefel is also the name given to
the leaves of Piper Betle. It contains volatile oils (Kemp), one
constituent of which, ehavicol (Eykman), appears to be character-
istic. A mixture of the nuts and leaves with a little lime, known-
shortly, as ‘‘Betel,’’ is universally used as a stimulating and exhila-
rating masticatory by the natives in the East, meeting, apparently,
some widespread physiological demand, The leaves of Pan (Hind.,)
are also used in various other ways as a common household drug,
The extract of the fruit of Gab or Diospyros embryopteris is a power-
ful astringent containing tannic acid. The rhizome of Geranium
maculatum, Spotted Cranesbill, or Alum-root, and the leaves and
stalks of Sumac, Sumach or Shumae (Rhus, various species) contain
both tannic and gallic acids. The fruit of sumach (Rhus glabra,
U. 8. P.) contains tannic and malic acids. Poison Ivy or Poison
Oak contains poisonous toxicodendric acid especially in spring.
The principal constituent of the root-bark of high blackberry
Rubus, U.S. P.) is tannic acid. Acacia Cortex, Acacia Bark or
abool, resembles oak-bark in containing tannic acid.
Gallie Acid, C,H,O,,H,O (p. 340) (Acidum Gallieum,
U.5. P.), occurs in smal] quantity in oak-galls and other vege-
table substances, but is always prepared from tannic acid.
Gallic acid forms slender acicular, fawn-colored crystals, solu-
ble in 100 parts of cold or 5 of boiling water, freely soluble
in alcohol, sparingly in ether.
Boil one part of coarsely powdered galls with four fluid parts
of dilute sulphuric acid for half an hour; strain through calico
while hot; collect the erystals that are deposited on cooling,
and purify these by treatment with animal charcoal and by
repeated crystallization.
Tests.—To an aqueous solution of gallic acid add a neutral
solution of a ferric salt; a bluish-black precipitate of ferric
gallate is produced, similar in appearance to ferric tannate.
Ferrous salts are also blackened by gallic acid. To more of
the solution add an aqueous solution of gelatin; no precipi-
tate is formed. By the latter test gallic acid is distinguished
from tannic acid.
Pyrogallie acid or pyrogallol U.S. P., C,A(OH),.—This sub-
stance sublimes in light feathery crystals when gallic acid is heated,
Or it may be formed by heating gallic acid with 8 or 4 times its
weight of glycerin to a ternperature of 190° or 200° C. for a short
time, pnell cantbvonc anhydride is no longer evolved, Longer heat-
ing at a lower temperature is not equally effective, and below
100° ©. probably no pyrogallol is produced (Thorpe). To an
THE ACID RADICALS,
aqueous solution add a neutral solution of a ferric salt; a red color
is produced. To another portion add a ferrous salt; a deep-blue
color results,
Test for the three acids, tannic, gallic, and pyrogallic.—To
three separate small quantities of milk of lime in test-tubes
add, respectively, tannic, gallic, and pyrogallic acids; the first
slowly turns brown, the second more rapidly, while the pyro-
gallic mixture at once assumes a beautiful purplish-red color
changing to brown, These reactions are characteristic ; they
are accompanied by absorption of oxygen from the air.
Use of Pyrogatlol in Gas-analysis.—A mixture of pyrogallol and
solution of potassium hydroxide absorbs oxygen with such rapidity
and completeness that concentrated solutions of each, passed up
successively by means of a pipette into a graduated tube con-
taining air or other gas, over mercury, form an excellent means
of determining free oxygen. The value of this method may be
proved roughly by pouring a small quantity of each solution into
a bottle, immediately and firmly closing its mouth with a cork,
thoroughly shaking the bottle, and then removing the cork under
water: the water rushes in and occupies about one-fifth of the
previous volume of air, indicating that the atmosphere contains
one-fifth of its bulk of oxygen. The small quantity of carbonic
anhydride present in the air is also absorbed by the alkaline
liquid; in delicate experiments this should first be removed by
means of the caustic alkali and the pyrogallol then be added,
Tarocyanre Acip, HSCN, anp ormER THIOCYANATES.—
Boil together sulphur and solution of potassium cyanide; solu-
tion of potassium thiocyanate, KSCN, is formed, Warm the
liquid, add hydrochloric acid until it faintly reddens litnvus-
paper, and filter; any potassium sulphide is thus decomposed,
and the solution may then be used for the following reactions,
The salt readily crystallizes,
Tests.—T a smal] portion of the solution add ferrie chlo-
ride; a deep blood-red solution containing ferric thiocyanate is
formed. (Solutions of pure ferrous salts are not colored b
thiocyanates.) To a portion of the red liquid add a little
hydrochloric acid; the color is not discharged (ferric mecon-
ate, asalt of similar tint, is decolorized by hydrochloric acid),
In the acid liquid place a fragment or two of zine; hydrogen
sulphide is evolved, and the red color disappears.
To another portion of the ferric thiocyanate add solution
of mercurie chloride ; the color is at once discharged. (Ferrie
THIOCYANATES. 345
meconate is unaffected by mercuric chloride.) The reaction
with ferric salts is the best test for the presence of a thio-
cyanate; and indirectly is also a good test for the presence of
hydrocyanic acid or other cyanide (see p. 269). Red ferric
acetate solution is decomposed by ebullition, Neither the
ferric acetate nor the meconate yields its color to ether; but,
on shaking ferric thiocyanate solution with ether, the latter
takes up the thiocyanate and heeomes of a purple color,
To a solution of a thiocyanate add solution of mercuric
nitrate; mercuric thiocyanate is precipitated as a white
powder.
Pharaoh's Serpents.—Mercuric thiocyanate, thoroughly washed
and made up into little cones, forms the toy termed Pharaoh’s
serpent. It readily barns when ignited, the chief product being
a light solid matter (melon, C,H,N,, and melam, O,H,N,,), which
isaues from the cone in a snake-like coil of extraordinary length.
The other products are mercuric sulphide (of which part remains
in the residue and part is volatilized), nitrogen, sulphurous anhy-
dride, carbonic anhydride, and vapor of metallic mercury.
The thiocyanic radical (SCN) is termed thiocyanogen, The
thiocyanates were formerly called su/phocyanides, Saliva contains
thiocyanates,
Uric Acip, C,H,N,O, axp orner Urares.—aAcidulate
a few ounces of human urine with hydrochloric acid and set
aside for twenty-four hours ; a few minute crystals of uric acid
will be found adhering to the sides and bottom of the veasel
and floating on the surface of the liquid.
Microscopical Test.—Place some of the floating particles on
a slip of glass, and examine them under a powerful lens or a
microscope ; the chief portion will be found in the form of
more or less square, yellowish, semi-transparent crystals, two
of the sides of which are even, and two very jagged ; but other
forms are common.
Chemical Test.—Collect more of the deposit, place in a
watch-glass or small white evaporating-dish, remove adherent
moisture by means of filter-paper, add a drop or two of con-
centrated nitric acid, and evaporate to dryness; the residue
will be red. When the dish is cold, add a drop of ammonia
water; a purplish-crimson color results. The color is deepened
on the addition of a drop of solution of potassium hydroxide.
Notes.—Urie acid (or lithic acid) and sodium, potassium, cal-
cium, and ammonium urates (or lithates) are common constituents
346 THE ACID RADICALS.
of animal excretions. Human urine contains about one part of
urate (usually sodium urate) in 1000, When more than this
is present, the urate is often deposited as a sediment in the excreted
urine, either at once, or after standing a short time, Uric acid
or other urate is also occasionally deposited before leaving the
bladder, and, slowly accumulating there, forms a common variety
of urinary calculus.—Some urates are not definitely crystalline ;
but, when treated with dilute nitric acid or a drop of solution of
potassium hydroxide and then a drop or two of acetic acid, micro-
scopic crystals of uric acid are usually formed,—aAL urates yield
the crimson color when treated as above described. This color is
due to a definite substance, murerid, C,H,N,O,, (from murex, a
shell-fish of similar tint, from whic h the ancient and highly valued
purple dye seems to have been prepared), and the test is known
as the murerid test. The formation of murexid is due to the
action of ammonia on alloxan, C,A,N,O,, 4H,0, and other white
crystalline products of the oxidation of uric acid by nitric acid,
Murexid is a good dye ; it may be prepared from guano (the excre-
ment of sea-fowl), which contains a large quantity of ammonium
urate. —The excrement of the serpent is almost pure ammonium
urate,
Urie acid and the urates will again be alluded to in connection
with the subject of morbid urine,
Constitution of Urie Acid.—The physiological aa pathological
importance of uric acid has obtained for it great attention from
chemists, For accounts of whut has been done in recent years
toward elucidating its constitution, students of organic chemistry
may consult the Pharmaceutical Journal, 3rd Series, vol, xiv.,
p. 771; vol. xv., pp. 119 and 411; and vol. xviii, p.69. ~
VaLeric Aci or VALERIANIC Actrp, HC,H,O, Anp
OTHER VALERATES.—In a test-tube place a few drops of amy]
alcohol (fusel-ovil, which is impure amyl alcohol, may be used)
with a little dilute sulphuric acid and a grain or two of potas
sium dichromate, cork the tube, set aside for a few hours, and
then heat the mixture ; valeric acid of characteristic valerian-
like odor, is evolved.
Valeric acid occurs in valerian-root in association with the essen-
tial oil from which it is apparently derived (sce p. 471), but is
usually prepared artificially, by the foregoing process, from amyl
alcohol, to which it bears the same relation that acetic acid does
to common alcohol :-—
C,H,OH + 20 = HC,H,0, + H,0
O,H,,0OH + 20 = HC,H,0, + H,0
Sodium Valerale, NaOQ,H,0,, is prepared from the valerie acid
and amyl valerate obtained on distilling a mixture of amyl aleohol,
VALERATES.
sulphuric acid, potassium dichromate, and water, The mixture
should stand for several hours before heat is applied.
CH,OH + 20 = HCHO,’ H,O
ene Oxygen Valeric neid J Water
2OH,OH + 20 = CHACHO, + 2H,0
cohol Oxygen Amy! valerate Water
The distillate is saturated with sodium hydroxide, which not
ofily yields sodium valerate with the free valeric acid, but also
decomposes the amyl valerate produced at the same time, more
sodium valerate being formed and some amyl alcohol set free,
according to the following equations :— ‘
HC,H,O, + NaOH = NaC.H,O, + H,O
Valeric acid sddium hydroxide Sodium valerate Water
CH,C,H,O, + NaOH = NaC,H,O, + C,H,OH
Aimyl valerate sodium hydroxide Sodinm valerate Amy! alcohol
From the solution of sodium valerate (which should be made neu-
tral to test-paper by careful addition of sodium hydroxide solution)
the solid white salt is obtained by evaporation to dryness and cau-
tious fusion of the residue. The mass obtained on cooling should
be broken up and kept in a well-closed bottle. It should be entirely
soluble in alcohol.
Other Valerates, as zinc valerate, Zn(CJH,O,), (Zinei Valeraa,
U.S. P.), and ferric valerate, Fe(CJH,O,),, may be made by the
interaction of sodium or other valerate and the sulphate or other
sult of the metal the valerate of which is desired, the new valerate
either precipitating or crystallizing out. A hot solution of zine
sulphate (5} parts) and sodium valerate (5 parts) in water (40 parts)
gives a crop of crystals of zinc valerate on cooling. Ammonii
Valeras, U.S. P., in white lamellar crystals, results when dry
immonia gas is passed into valerie acid,
Tests.— Heated with dilute sulphuric acid valerates of the
metals give a highly characteristic smell (valerie acid ),
Note.—Of the four possible varieties of valerates, the foregoing
are the ordinary or éxo-va/erates, the constitutional formula for the
acid being (CH,), = CH —CH,— COOH, See the Acetic Series
of Acids in the Hection on Organic Chemistry.
The amy! alcohol (C,\H,,OH) from which valerates are prepared
may contain the next lower member of the homologous series of
alcohols, butyl aleohol, CLH,OH. This alcohol, during the oxi-
dation, will be converted into butyric acid, HC HA , the next
lower homologue of valeric acid, HC,H,O,, and hence the various
valerates may be contaminated by some ytyrates, These are
detected hy distillation with dilute sulphuric acid and addition of
348 THE ACID RADICALS.
solution of cupric acetate to the distillate, which at once becomes
turbid if butyric acid be present. In this reaction valeric acid and
and butyric acid are produced by interaction of the valerate and
butyrate and the sulphuric acid, and they distill over on the appli-
cation of heat. On the addition of cupric acetate, Cu(C,H,O,),,
cupric butyrate, Cu(C,H,O,),, is formed, and, being ost
insoluble in water, is at once precipitated, or remains suspended,
giving a bluish white opalescent liquid. Cupric valerate,
Cu(C,H,0,),, is also formed after some time, but is far more soluble
than the butyrate, and only slowly collects in the form of greenish
oily drops, which gradually pass into greenish-blue hydrous crys-
talline cupric valerate (Larocque and Huralt).
QUESTIONS AND EXERCISES,
Mention a test for nitrites in potable waters.—Which nitrates are
official ’—Give the names of some natural and artificial silicates —“What
is soluble glass’’ ?—Distinguish between silica and silicic acid.—How are
silicates detected ?—What is the quantivalence of silicon ?—Mention the
sources, formule, and analytical reactions of succinates.—-State the mode
of manufacture of and tests for thiocyanates.—What proportion of tannic
acid is contained in galls?—Describe the process for the preparation of
tannic acid.—Explaie the chemistry of “tanning.”—Enumerate the tests
for tannic acid.—What is the formula for tannic acid ?—Mention official
substances other than galls whose astringency is due to tannic acid.—
How is gallic acid prepared 7—By what reaction is gallic acid distinguished
from tannic acid ?—Mention the characteristic properties of pyrogullic
mid.—Explain the murexid test for uric acid.—Describe the artificial
preparation of valeric acid and other valerates, giving equations.—What
is the formula of valeric acid ?—How are butyrates detected in presence
of valerates?
DETECTION OF THE ACID RADICALS OF
SALTS SOLUBLE IN WATER,
In examining a salt soluble in water, and concerning which no
general information is obtainable, search must first be made for
the metallic radical by the appropriate methods (see pp. 388, 842,
etc.). The metal having been detected, consideration of the
character of its salts will indicate which acid radicals may be, and
which cannot be, present. Thus, for instance, if the substance
under examination is freely soluble in water and lead ia found
only the nitric and acetic radicals need be sought, none other of
the lead salts than nitrate or acetate being freely soluble in water,
Moreover the salt is more likely to be lead acetate than nitrate
for two reasons: the former is more soluble than the latter,
is by far the commoner salt of the two. Medical and pharmaceuti-
cal students have probably, in dispensing, already learnt much
ANALYTICAL DETECTION OF ACID RADICALS, 349
concerning the solubility of salts, and whether a salt is rarely
employed or is in common use, And although but little depend-
ence can be placed on the chances of a salt being present or absent
according to its rarity, still the point may have its proper weight.
If, in a mixture of salts, ammonium, potassium, and magnesium
have been found associated with the sulphuric, nitric, and hydro-
chloric radicals, and we are asked how we suppose these bodies may
have existed in the mixture, we are much more likely to be correct
if we suggest that sal-ammoniac, nitre, and Epsom salt were
originally mixed together, than if we suppose any other possible
combination. Such appeals to experience regarding the solubility
or rarity of salts cannot be made by any one unacquainted, or
insufficiently acquainted, with the characters of salts; in such
cases the relation of a salt to water and acids can be ascertained
by referring to the following Table (p. 351) of the solubility or
insdlubility of about five hundred of the common and rarer salts
met with in chemical operations,
The alternative course to the above (namely, to ascertain which
acid radicals are present in a mixture, and then to appeal to
experience to tell which metallic radicals may be and which can-
not be present) is impracticable; for acid radicals cannot be sepa-
rated out, one after the other, from one and the same quantity of
substance by a similarly simple treatment to that already given for
metallic radicals. Indeed such a separation of acid radicals could
scarcely be accomplished at all, or only by a vast amount of labor.
The metallic radicals must therefore be detected first.
Even when the metallic radicals have been found, the acid radi-
cals which may be present must be sought for singly, the chief
additional aid which can be brought in being the action of sul-
phurie acid, a barium salt, a calcium salt, silver nitrate, and ferric
chloride on separate small portions of the solution under examina-
tion, as detailed in the second of the following Tables,
Qualitative Analysis.
Before commencing the analysis of an aqueous solution of a
salt or salts, the metallic radicals in which are known, ascer-
tain which acid radicals may be, or, what comes to the same
thing, which cannot be present. ‘To this end, consult the
following Table (p. 351) of the solubility of salts in water.
Look for the name of the metal of the salt in the vertical
column ; the letters S and I indicate which salts are soluble
and which insoluble in water, an asterisk attached to the S
meaning that the salt is slightly soluble.
Some of the salts marked as insoluble in water are soluble in
aqueous solutions of soluble salts, a few forming soluble double
380 THE ACID RADICALS,
salts. To characterize salts as soluble, slightly soluble, or insolu-
ble, only roughly indicates their relation to water: on the one
hand, very few salts are absolutely insoluble in water; on the other,
there is a limit to the solubility of every salt.
Tf only one, two, or perhaps three given acid radicals can be
present in the solution, test directly for it or them according to
the reactions given in the previous pages, If several may be
present, pour small portions of the solution, rendered neutral
if necessary by addition of ammonia, into five test-tubes, and
add respectively sulphuric acid, barium nitrate or chloride,
calcium chloride, silver nitrate, and ferric chloride; then con-
sult the Table on p. 352, in order to interpret correctly the
effects these reagents may have produced.
REMARKS ON THE TABLE, p, 352,
The first point of value to be noticed in connection with this
Table, is one of a negative character; namely, if either of the
reagents gives no reaction, it is self-evident that the salts which it
decomposes with production of a precipitate must be absent. Then,
again, if the action of one of the reagents indicates the absence of
certain acid radicals, those radicals cannot be among those precipi-
tated by the other reagent; thus, if the action of sulphuric acid
points to the absence of sulphides, sulphites, carbonates, cyanides,
and acetates, these salts may be struck out of the other lista, and
the examination of subsequent precipitates is so far simplified.
Or, if the barium precipitate is soluble in hydrochloric acid and
the calcium precipitate in acetic acid, neither sulphates nor oxa-
lates can be present, Observing these and other points of difference,
which will be seen on careful and thoughtful reflection, and
remembering the facts suggested by a knowledge of what metallic
radicles are present, one acid radical after another may be struck
off as absent or present, leaving only one or two as the objects
of special experiment. Among the chief difficulties to be encoun-
tered will be the separation from each other of chlorides, bromides,
iodides, and cyanides, or of tartrates from citrates, and confirmatory
tests of the presence of certaincompounds, These may all be sur-
mounted on referring back to the reactions of the various radi-
cals as described under their hydrogen salts, the acids,
In rendering a solution neutral, for the application of the various
group-tests, the necessary employment of any large amountof acid
or of alkali must be noted, the presence of alkaline hydroxides or
of free acids, respectively, being thereby indicated. The presence
of free acid is usually indicated by the abundant effervescence
which results on the addition of a carbonate.
Sulphuric acid, the first group-reagent, may itself yield by
reduction, especially when heated with certain solid substances,
OF THE SOLUBILITY OR INSOLUBILITY OF SALTS IN WATER.
ae =f
|
Arsenate.
Carbonate. |
Chioride.
| Oxalate.
Sulphate.
Sulphite
Tartrate,
| Arsenite,
|
Ca mt CD be | Sulphide.
| Adelina iM, ...sccecscccsciedvcoscsccsceesees
} ATIVIIOTIIUML ....ccses ceccnenes svvecsenavesses
Antimony........s00 ss aeeene seeees eenenanee
Barium ........000. seenneeds bueees Feeeeeveeees |
a as a ne |
| SATII acids sccepvaes ceenatusrpsecesscsces
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a
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PEI sas oiikivs manzastd Senhocead'e anuseenl
SUS Geka a ssah08d Uvaianateaseaaianil ehedel
NN said, iv veh noucnvrievinh aviansies Ksibioss
SRANNODS cevccrseccsetacssensevsuccncsssecvers
OSPR GEM ose tn cb onentvetadewsnecs una-aeese
BLO in vde cutace F288 BS d = aS ERR EE ae
cD i | Chromatle.
OF OS
=
Sa 0 ee | Oxide,
es ee ee
a
a
2
w
*
=
la ft
GO 90 56 0 = i Go Go
CD CD 2 C0 Oa ht tay es
| state ncn arn tn nace Oe ew
Se ee | Hydroxide.
8 Oe | lodide.
CO eee Das ee OG
— =
G2 00 00 G0 OG ee OF 0 0 et ee
:
~
<
=
=
x
:
S
=
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ee 2 0 bt we CC
De eS ee es es ee | Cyanide.
HS" Desa SH Doo
SSH eH Mee HPD Meee DD ee ee
ee ee ey
JS ES NTIS bk ft bt tt bt “2 tt “Od Dt tb Dt Dt Dt 0
1%
iv
—
A EE et at Ge bt hd wo CD
DRAMAS hdned eonoMEnnann.ow | Nitrate,
ee epee eee eet 1 Teper Teeter |
Oo Ta ee
te eee eet et et et et td et te et | Phosphate.
hm th th OD
SN aks ws fsa ck Gt bre Sedo 0d WD Na
CD he mt oe 0 ma th OD wo ~e
BES ~2HD—~-BHeSein~ Ew
tt te et et et et td et et ed ee et et
The asterisk indicates sigh solubility,
S
S
=
oS
5
bo
~
S
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‘NOLLNTOS SHOMAOVY 'IVHLOAN V NI ‘SELVULIO ONV ‘SaLVHASOnA
‘ST LVULUVL ‘SHLVIVXO ‘SHLVNOAUVO ‘SALVHAIOS “SULINA'1INS ‘SHCINAINS ‘SALVISOV ‘SULVUOU
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m
| nar
QUALITA Tl VE ANALYSIS. 353
sulphurous acid or hydrogen sulphide (see pp. 288 and 290); hence
the production of these from a diluted solution should alone be
regarded as evidence of the presence of a sulphide or sulphite.
Calcium chloride does not precipitate citrates readily or com-
pletely in the cold: therefore the mixture should be filtered and
the filtrate boiled; calcium citrate then separates. Calcium tar-
trate is soluble in solution of ammonium chloride when quite
freshly precipitated, but not after it has become crystalline,
From their solutions in ammonium chloride, calcium tartrate is
mostly precipitated by ammonia, and calcium citrate on boiling,
The rarer acid radicals will be very seldom met with. The
presence of benzoates, hippurates (which give benzoic acid), hypo-
chiorites, thiowwlphates, nitrites, and valerates will be indicated
during the treatment with sulphuric acid. Ferrocyanides, Jerri-
cyanides, meconates, suecinates, thiocyanates, tannates, and gallates
are among the salts whose presence is indicated by ferric chloride;
JSormates, hypophosphites, malatea, and others are indicated by silver
nitrate. Urates char when heated, giving an odor resembling
that of burnt feathers,
In actual practice the analyst nearly always has some clue to
the nature of rarer substances placed in his hands,
If chromium and arsenic have been detected among the metallic
radicals, these elements may be present in the form of chromates
arsenates, and arsenifes, yielding with barium chloride yellow
barium chromate and white barium arsenate and arsenite, and with
silver nitrate red silver chromate, brown silver arsenate, and yellow
silver arsenite.
QUESTIONS AND EXERCISES,
In analyzing an aqueous solution of salts, for which radicals would you
first search, the metallic or the acid, and why?—In an aqueous solution
there have been found magnesium (Mg) and potassium (K), with the
sulphuric radical (SO,), and iodine (I); state which salts were probably
dissolved originally in the water, and mention the considerations which
guide you to the conclusious.—Give a sketch of the methods by which
you would examine a neutral or only faintly acid aqueous liquid for the
acid radicals which might be present. In what stages of the examination
would the following salts be detected? «. Carbonates and Sulphates,
‘+, Oxnlates. c. Turtrates and Nitrates. dd. Acetates and Sul phites.
e. Bromides and Cyanides. ff. Borates. g. Iodides and Phosphates.
kh. Chlorates, Oxalates, and Acetates. i. Chlorides and Todides, j, Sul-
phites. k. Salphides, Carbonates, and Nitrates. |. Citrates and Sul-
phates.—Silver nitrate gives no precipitate in a given aqueous solution ;
what acid radicals may be present ?’—Barium ehloride gives no precipi-
tate in a given neutral solution, but silver nitrate gives a white precipi-
tute; whatacid radicala are indicated ?—Ferric chloride produces a
deep-red color ina solution, calcium chloride yielding no precipitate ;
what salts may be present, and how may they be distinguished from each
Other ’—Ferric chloride gives & black precipitate in a solution in which
sulphuric acid develops no odor ; to what is the effect due?
23
QUALITATI VE ANALYSIS.
ANALYSIS OF SALTS.
SINGLE OR MIXED, SOLUBLE OR INSOLUBLE.
Thus far, most of the substances which have been considered,
especially those of pharmaceutical interest, have been regarded as
definite compounds, and as having certain well- defined radicals
termed metallic and acid respectively: moreover attention has been
designedly restricted to those definite compounds which are
soluble in water. But there still are numerous substances having
no definite or known composition; and of those having definite
composition there are many having no definitely ascertained
radicals. Again, of those having definite composition, and whose
constitution has been in part or entirely elucidated, there are
many insoluble in water,
Chemical substances of whose composition or constitution little
or nothing is at present known, are chiefly of animal and vegetable
origin ; they are not of immediate importance, and may be omitted
from consideration here.
Of substances which are definite in composition, but whose
parts or radicals are unknown or imperfectly known, there are
only a few (such as the alkaloids, amylaceous and saccharine
matters, the glucosides, and the albuminoid, resinoid, and animal
and vegetable coloring matters) which have any considerable
amount of medical or pharmaceutical interest; these will be
noticed subsequently,
Definite compounds most frequently present themselves ; and
of these by far the larger proportion (namely, the salts soluble in
water) have already been studied. There remain, however, many
salts which are insoluble in water, but which must be brought
into a state of solution before they can be effectively examined.
The next subject of laboratory work is, therefore, the analysis of
substances which may or may not be soluble in water. This will
involve no other analytical schemes than those which have been
given, and will in only one or two cases increase the difficulty of
the analysis of a precipitate produced by a group-reagent ; but it
will give roundness, completeness, and a practical bearing to the
student’s analytical knowledge. Such laboratory work will at the
sume time bring into notice the methods by which substances
insoluble in water are manipulated for pharmaceutical purposes,
orare made available for use as food for plants, or as food or
medicine for man and animals generally,
Preliminary Examination of Solid (chiefly mineral) Salts.
Before attempting to dissolve a salt for analysis, its appearance
and other physical properties should be noted, and the influence
of heat and concentrated sulphuric acid should be
Unless the operator knows how to interpret what is thus observed,
QUALITATIVE ANALYSIS. 300
and to what extent he can place confidence in his observations,
he should omit the preliminary examination altogether, except
when he is able to follow it out under the guidance of a judicious
teacher; for it is impracticable here to do more than hint at the
results which may be obtained by such an examination,or so to
adapt descriptions as to prevent a student allowing unnecessary
weight to attach to preconceived ideas.
Whatever be the course pursued, short memoranda describing
results should invariably be entered in the note-book.
1. Examine the physical characters of the salt in various
ways, but only rarely and cautiously, by the palate, on
account of the danger of so doing.
If the salt is, to the eye, white, little more than traces of
distinctly colored substances can be present; if colored, the tint
may indicate the nature of the substance or of one of its constit-
uents, supposing that the student is already acquainted with the
colors characteristic of certain salts. Closer observation, aided
perhaps by a lens, may reveal the presence, in a pulverulent
mixture, of small crystals or pieces of a single substance; these
should be picked out by means ofa needle or forceps and examined
separately. In a powder or roughly pulverized mixture of sub-
stances, the process of sifting (through such sieves as muslin of
different degrees of fineness) often mechanically separates sub-
stances, and thus greatly facilitates analysis. The substances
may present an undoubted metallic appearance, in which case
only the metals existing under ordinary atmospheric conditions
need, as a rule, be sought for. Peculiarity in smell reveals the
presence of ammonia, hydrocyanic acid, hydrogen sulphide, ete,
Between the fingers a substance is, perhaps, hard, soft, or gritty,
and from such a character useful inferences may be drawn. Or
the substance may be heavy, like the salts of barium or lead, or
light, like the magnesium carbonates and oxides; or it may be
one of the pharmaceutically well-known class of ‘‘scale’’ pre-
parations,
2. Place a grain or two of the salt in a dry test-tube or in
a piece of glass tubing closed at one end, and heat it, at first
gently, =e more strongly, and finally, if necessary, in the
blowpipe-flam
Gases or vapors of characteristic appearance or odor may be
evolved, such as iodine, nitrous fumes, sulphurous anhydride,
hydrocyanic acid, or ammonia, Much steam given off by a dry
substance indicates either hydroxides or salts containing water of
crystallization. (A small quantity of interstitial moisture often
causes heated crystalline substances to decrepitate—trom decrepo,
|
om |
356 QUALITATIVE ANALYSIS,
I crackle—that is, break up with slight explosive violence, owing
to the expansive force of the steam suddenly generated.) A
sublimate may result, due to salts of ammonium, mercury, or
arsenic, to oxalic or benzoic acid, or to sulphur free or as a sul-
phide—a salt wholly volatile containing such substances only.
The compound may blacken, pointing to the presence of organic
matter—which, in ordinary salts, will probably be in the form of
acetates, tartrates, and citrates, or as common salts of the alkaloids
morphine, quinine, strychnine, or as starch, sugar, salicin ; or it
may be in other definite or indefinite forms common in pharmacy,
and for which tests will be given in subsequent pages, If no
charring occurs, the important fact is established that organic
matter is not likely to be present—except perhaps cyanides,
formates, or oxalates, which do not char. The residue may
change color from the presence or development of zine oxide, iron
oxide, etc., or melt from the presence of a fusible salt and absence
of any large proportion of infusible salt, or be unaltered, showing
the absence of any large amount of such substances.
3. Place a grain or two of the salt in a test-tube, add a
drop or two of concentrated sulphuric acid, cautiously smell-
ing any gas that may be evolved ; afterward slowly heat the
mixture, noticing the effect, and stopping the experiment
when any sulphuric fumes begin to escape.
lodine, bromine, and nitrous or chlorine-like fumes wil! reveal
themselves by their color, indicating the presence of iodides,
iodates, bromides, bromates, nitrates, and chlorates. The evolu-
tion of a colorless gas, fuming on coming into contact with air
and having an irritating odor, points to chlorides, fluorides, or
nitrates. Gaseous products having a greenish color and odor of
chlorine indicate chlorates, hy pochlorites, or chlorides mixed with
other substances. Slight sharp explosions betoken chlorates.
Evolution of colorless gas may proceed from cyanides, acetates,
sulphides, sulphites, carbonates, or oxalates. Charring will be
due to citrates, tartrates, or other organic matter. If none of
these effects is produced, most of the above-named substances are
absent or only present in minute proportion. The substances
apparently unaffected by the treatment are metallic oxides,
borates, sulphates, and phosphates.
4. Expose some of the substance to the blow-pipe flame on
platinum wire, with or without a bead of borax or of miero-
cosmic salt' (sodium, ammonium, hydrogen phosphate,
NaNH,HPO,, 4H,O0); on platinum foil, or in a porcelain
crucible, or on a crucible lid, with or without sodium carbon-
' So called because formerly obtained from the urine of man, who was
ealled the microcoemos or little world.
SOLID SUBSTANCES, 307
ate ; or on charcoal, alone or in conjunction with sodium car-
bonate, potassium cyanide, or cobalt nitrate. This experiment
will sometimes yield important information, especially to one
who has devoted much attention to reactions producible by the
blow-pipe flame. The medical or pharmaceutical student,
however, will seldom have time to work out this subject to an
extent sufficient to make it a trustworthy guide in analysis.
Methods of Dissolving and Analyzing Single or Mixed
Solid Substances.
Having submitted the substance to preliminary examination,
proceed to dissolve and analyze by the following methods. Theae
operations consist in treating the well-powdered substance con-
seeutively with cold or hot water, hydrochloric acid, nitric acid,
nitro-hydrochlorie acid, or fusing alkali-metal carbonates and
dissolving the product in water and acid, The resulting liquids
are analyzed in the manner already described, or by slightly
modified processes as detailed in the following paragraphs.
Solution in Water.—Boil about a grain of the salt presented
for analysis in about a third of a test-tubeful of water. If it
dissolves, prepare a solution of about 20 or 30 grains in
half an ounce or more of water, and proceed with the analy-
sia in the usual way, testing first for the metallic radical
or radicals by the proper group-reagents (HC1, H,8, NH,SH,
(NH,),CO,,(NH,),HPO,), p. 242, and then for the acid
radical or radicals, directly or by the aid of the prescribed
reagents (H,SO,, BaCl,, CaCl, AgNO,, FeCl,), p. 352.
If the salt is not wholly dissolved by the water, ascertain
whether or not any has entered into solution, by filtering, if
necessary, and cautiously evaporating a drop or two of the
clear liquid to dryness on platinum foil; the presence or
absence of a residue gives the information sought for. If any-
thing is dissolved, prepare a sufficient quantity of solution for
analysis and proceed as usual, reserving the insoluble portion
of the mixture, after thoroughly exhausting with water, for
subsequent treatment with acids.
Solution in Hydrochloric Acid.—If the salt is insoluble in
water, digest about a grain of it (or of the insoluble portion
of a mixed salt) in a few drops of hydrochloric acid, adding
water and boiling if necessary. If the salt wholly dissolves,
prepare a sufficient quantity of the liquid, noticing whether
or not any effervescence (due to the presence of sulphides,
sulphites, carbonates, or cyanides) occurs, and proceed with
358 QUALITATIVE ANALYSIS.
the analysis as before, except that the first step, the addition
of hydrochloric acid, may be omitted,
The analysis of this solution will in most respects be simpler
than that of an aqueous solution inasmuch as the majority of salts
(all those soluble in water) will be absent. This acid solution
will, in short, only contain :—chlorides produced by the action of
the hydrochloric acid on sulphides, sulphites, carbonates, cyanides,
oxides, and hydroxides ; and certain borates, oxalates, Lr,
sulphates, tartrates, and citrates (possibly silicates and fluorides),
which are insoluble in water, but soluble in acids without
apparent decomposition, Sulphides, sulphites, carbonates, and
cyanides will have revealed themselves by the occurrence of effer-
vescence during solution; and the presence of oxides and hydroxides
may (p. 361) be inferred by the absence of compatible acid radicals,
The borates, oxalates, phosphates, tartrates, and citrates alluded of
will be reprecipitated in the systematic analysis as soon as the acid to
the solution is neutralized ; that is, will come down as such when
ammonia and ammonium hydrosulphide are added in the usual
course, Of these precipitates, only the calcium oxalate and the cal-
cium and magnesium phosphates need occupy attention now, for ba-
rium oxalate and phosphates seldom or never occur, and the borates,
tartrates, and citrates met with in medicineor general analysis, are
all soluble in water. These phosphates and, oxalates, then, will be
precipitated in the course of analysis along with iron, their presence
not interferring with the detection of any other metal, If, from the
unusually light color of the ferric precipitate, phosphates and oxal-
ates are suspected, it is treated according to the following Table :—
PRECIPITATE OF PHosPHATES, OXALATES, FERRIC
HYDROXIDE, ETC,
Dissolve in HCl, add citric acid, then NH,OH, and filter;
then follow the Table below.
ee
Filtrate Precipitate
Fe Ca,(PO,),, CaCjOy, Mgy( PO,),
Add HC! and Boil in acetic ac ‘cid, and filter.
K,Fe(CN le
Blue ppt. — i ; Hiatal
Insoluble Ca,(PO,),, PO,)
CaCO, Add (NH,).C tim ‘stir’ Alter,
White —- ee
(CaF, may nae
deme ype. recipitate Filtrate
occur here) white add NILOM.
indicating | White Bp
{ aa PO), | MgNH,
oe —
" Most oxalates, after ignition, e sf “TVesC® On the addition of acid ; Muor-
ides may be detected by the “ etching” test.
SOLID SUBSTANCES. 359
In analyzing phosphates and oxalates, advantage is also
frequently taken of the facts that the phosphoric radical is wholly
removed from solution of phosphates in acid by the addition of
an alkali-metal acetate and ferric chloride, and subsequent ebul-
lition, as described under ‘‘Phosphoric Acid’’ (p, 316), and that
dry oxalates are converted into carbonates by ignition as mentioned
under ““Oxalic Acid’’ (p. 304).
Certain arsenates and arsenites, insoluble in water but soluble
in hydrochloric acid, may accompany the above phosphates and
oxalates if from any cause hydrogen sulphide has not previously
been passed through the solution, or has only been passed for an
insufficient length of time.
If the substance insoluble in water does not wholly dissolve
in hydrochloric acid, ascertain if any has entered into solution,
by filtering, if necessary, and evaporating a drop of the clear
liquid to dryness on platinum foil; the presence or absence of a
residue gives the information sought for. If anything 1s dis-
solyed, prepare a sufficient quantity of solution for analysis,
and proceed as usual, reserving the insoluble portion of the
mixture, after thoroughly exhausting with hydrochloric acid
and well washing with water, for the following treatment by
nitrie acid.
Solution in Nitric Acid.—If the salt is insoluble in water
and hydrochloric acid, boil it, (or that part of it which is
insoluble in these menstrua) in a few drops of nitric acid, If
it wholly dissolves, remove excess of acid by evaporation,
dilute with water, and proceed with the analysis.
This nitric acid solution can contain only a few substances; for
nearly all salts soluble in nitric acid are also soluble in hydrochloric
acid and, therefore will have been removed previously. Some of
the metals, however (Ag, Cu, Hg, Pb, Bi), as well as amalgams
and alloys, unaffected or scarcely affected by hydrochloric acid,
are readily attacked and dissolyed by nitric acid. Many of the
sulphides, also, insoluble in hydrochloric acid, are dissolved by
nitric acid, usually with separation of sulphur. Calomel is con-
verted, by long boiling with nitric acid, into mercuric chloride
and nitrate. The nitrates here produced are soluble in water,
The nitric acid solution, as well as the hydrochloric acid and
mucous solutions, should be examined separately. Apparently,
time would be saved by mixing the three solutions together and
making one analysis. But the object of the analyst is to separate
every radical from every other; and when this has been partially
fecomplished by solvents, it would be unwise to again mix and
separate a second time. Moreover, solvents often do what the
chemical reagents cannot do—namely, separate sa/fs from each
QUALITATIVE ANALYSIS.
other. This is important, inasmuch as the end to be attained as far
as possible in analysis is not only an enumeration of the radicals
present, but a knowledge of the actual condition in which they
are present; the analyst must state, when this is possible, of what
sults a given mixture was originally formed—how the metallic and
acid radicals were originally distributed. In attempting this,
much must be left to theoretical considerations, and i is often
impossible to arrive at certainly accurate conclusions ; but a pro-
cess by which the salts themselves are separated is of practical
assistance, hence the chief advantage of analyzing separately the
solutions resulting from the action of water and acids on a solid
substance,
Solution in Nitro-hydrochloric Acid.—If the salt or any
part of a mixture of salts is insoluble in water, hydrochloric
acid, and nitric acid, digest it in nitro-hydrochlorie acid,
warming, or even boiling gently, if necessary ; evaporate to
remove excess of acid, dilute, and proceed as before.
Mercuric sulphide and substances only slowly attacked by
hydrochloric or nitric acid, as, for example, calomel and ignited
ferric oxide, are sufficiently altered by the free chlorine of aqua
regia to become soluble.
Analysis of Insoluble Substances,
If the substance is insoluble in water and aeids, it is one
or more of the following substances :—Sand and certain sili-
cates, such as pipeclay and other clays; fluor-spar ; eryolite,
Na ALF; barium, strontium, and possibly calcium sulphates;
tinstone ; antimonic oxide; glass; felspar (aluminium and
alkali-metal silicates); silver chloride, bromide, or iodide;
lead sulphate, It may also be or contain carbon or carbon-
aceous matter, in which case it is black and combustible,
burning entirely or partially away when heated in the air—
or it may be or contain sulphur, in which case sulphurous
anhydride is evolved, detected by its odor, when the substance
is heated in air. A drop of solution of ammonium hydrosul-
phide added to a little of the powder will at once indicate the
presence or absence of salts of such metals as lead and silver.
For the other substances, proceed according to the following
(Bloxam’s) method :—
Four or five grains of the dry substance are intimately
mixed with twice the quantity of dried sodium carbonate, and
this mixture is well rubbed in a mortar with five times its
weight of deflagrating flux (1 of finely powdered charcoal to
INSOLUBLE SUBSTANCES, 361
6 of nitre). The resulting powder is placed in a thin porce-
lain dish, or crucible, or clean iron tray, and a lighted match
applied to the centre of the heap. Deflagration ensues, and
decomposition of the various substances occurs, the acid
radicals going to the alkali-metals to form salts soluble in
water, the metallic radicals being simultaneously converted
into carbonates or oxides. ‘The mass is boiled in water for a
few minutes, the mixture filtered, and the residue well washed.
The filtrate may then be examined for acid radicals and
aluminium, tin, etc.,, and the residue be dissolved in dilute
hydrochloric acid and analyzed by the ordinary method.
The only substance which resists this treatment is chrome
iron-ore,
To detect alkali in felspar, glass, or eryolite, Bloxam recom-
mends deflagration of the powdered mineral with one part of sul-
phur and sixof barium nitrate. The mass is boiled in water, the
mixture filtered, ammonium hydroxide and carbonate added to
remove barium, the mixture again filtered, and the filtrate
evaporated and examined for alkali-metals by the usual process,
Hydroxides and Oxides.
If no acid radical can be detected in a substance, or if the
quantity found is Obviously insufficient to saturate the quantity
of metallic radical present, the occurrence of oxides or hydroxides,
or both, may be suspected, Confirmation of their presence will
be found in the general rather than in any special behavior of the
substances. Some hydroxides yield water when heated—in a dry
test-tube held nearly horizontally in the flame, so that moisture
may condense on the cool part of the tube. Some oxides yield
oxygen—detected by heating in a test-tube, and inserting the
incandescent end of a strip of wood. Soluble hydroxides cause
abundant evolution of ammonia when heated with solution of
ammonium chloride.‘ Soluble hydroxides also give characteristic
precipitates with the various metallic solutions. Hydroxides and
oxides insoluble in water, not only neutralize much nitric acid, or
acetic acid, but are thereby converted into salts soluble in water.
Moat oxides and hydroxides have a characteristic appearance. In
short, some one or more properties of an oxide or a hydroxide
will generally betray its presence to the student who not only has
knowledge respecting chemical substances, but has cultivated the
faculties of observation and perception,
‘Red litmus-paper placed over the mouth ofa test-tube in which ammo-
niam chloride solution alone is being boiled turns blue, but phenol-
pthalein paper is not affocted.,
362 QUALITATIVE ANALYSIS,
Fractional Operations.
Not only is the common process of sifting (p, 355) through
sieves of varying degrees of fineness a useful fractional operation
or separatory adjunct in analytical as in other work, but also
fractional elufriation (p, 134), fractional solution of a mixed mass
by dixiviation (p. 89) of the substance with successive small quan-
tities of solvents, and fractional precipitation with filtration after
each addition of successive small quantities of a precipitant are
often valuable aids. Fractional disti//ation (see p, 420) is often
very useful, fractional sublimation (p, 96) and fractional erystalli-
zation (p. 82) occasionally, fractional fusion less often.
QUESTIONS AND EXERCISES,
Describe the preliminary treatment to which a salt may be subjected
prior to systematic analysis.—Mention substances which might be recog-
nized by smell.—Mention some salts which are heavy, and some which are
light.—Name some substances recognizable by their color,—W hat infer-
ence may be drawn from the appearance of steam when dry substances
are heated ?—Why docertain crystals decrepitate ?—If «a powder sublimes
on being heated, to what classes of compounds may it belong?—When
heat causes charring, what conclusion is drawn ?—No change occurring
by heat, what substances cannot be present?—Give examples of salts
which are identified by their behavior with concentrated sulphuric acid,
and by their comportment in the blow-pipe flame, with or without borax
or microcosmic salt.—What are the solvents usually employed in endoav-
oring to obtain a substance in a state of solution, and what is the order
of their application ?—Name a few salts which may be present in an
aqueous solution.—Mention some common compounds insoluble in water,
bat soluble in hydrochloric acid.—What substances are only attacked by
nitric acid or nitro-hydrochloric acid ?—At what stage of analysis do
arsenites and arsenates show themselves ?—Sketch a method for the eom-
plete analysis of aliquid suspected to be an aqueous solution of nentral
salts.—How can alkaline-earth-metal phosphates and oxalates and ferric
hydroxides be separated from each other ?—How would you proceed to
analyze an alloy ’—By what process may substances insoluble in water or
acids be analyzed ’—How would you qualitatively analyze glass?
RECAPITULATORY AND OTHER NOTES ON SALTS,
The molecules of a salt contain radicals which may be either
elementary or compound (pp. 52, 64),
Fach radical has a definite exchangeable value, but this value
may differ in the case of different radicals (p. 62).
The relation to each other of the radicals in organic substances
or salts, is apparently much more complex than the relation to
each other of the radicals in inorganic or mineral salts,
Bertholle? s Laws.—‘' When we cause two salts to react by
means of a solvent, if, in the course of double decomposition, a
THEORY OF SOLUTION. 363
new salt can be produced less soluble than those which we have
mixed, this salt will be produced.’’ ‘‘ When we apply dry heat
to two sults, if, by double decomposition, a new salt can be pro-
duced more volatile than the salts previously mixed, this salt will
be produced.”’
THEORY OF SOLUTION,
The phenomena of electrolysis have given rise to a new theory
of solution, Formerly a salt was supposed to consist of a basic
oxide combined with an acid oxide ; thus ‘‘ sulphate of soda’’ (as
the salt now known as sodium sulphate was called) was regarded
as Na,O,50,. When a solution of sodium sulphate is electrolyzed
(see p. 67), sodium hydroxides is formed at the negative, and sul-
phuric acid at the positive electrode ; these substances were sup-
posed to be produced by the union of the sodium oxide with water
at the negative electrode and of the sulphuric anhydride with water
at the positive electrode. To account for such phenomena a new
theory has, however, been brought forward, according to which,
a salt—e. g., sodium sulphate—when dissolved in water splits up
into an electro-positive and an electro-negative part, but these
are now supposed to be, not the basic oxide and the acid oxide,
but the metallic or basic radical and the acid radical. Sodium
atoms or tons constitute the positive part, sulphate radicals or
sulphations (SO,) the negative part ; when an electrical current is
passed through the solution the former lose their charges of posi-
tive electricity at the negative electrode and then act on the water,
forming sodium hydroxide and liberating hydrogen; the sulpha-
tions similarly lose their charges of negative electricity and then
decompose the water at the positive electrode, forming sulphuric
acid and liberating oxygen, When Arrhenius brought forward this
view, anew theory of solution was much needed, for it had been
found by careful measurements that the thermal change involved
in the act of solution could not be entirely accounted for by the
physical change of state. Arrhenius assumed that a salt on pass-
ing into solution undergoes more or less complete separation into
its ions (ionization), and that its ions act independently of each
other, not only in electrolytic, but also in chemical processes, In
general, we find chemical activity, in the sense of readiness to
undergo double decomposition, to go hand in hand with electrical
conductivity, and his explanation is that the real carriers of the
electricity are the free ions, which, by virtue of their freedom, are
chemically active, since they have not to be separated from each
other before they interact
This hypothesis of the existence of free ions in solution has
thrown much light on the general behavior of salt solutions, and
has rendered possible un explanation of many hitherto inexplic-
able phenomena.
o64 THE PERIODIC LAW.
THE PERIODIC LAW.
When the elements are arranged in the order of their atomic
weights, it is found that, starting with lithium, the chemical proper-
ties of each successive element differ in many cases only to a rela-
tively small degree from those of the element immediately preced-
ing. This holds for a ‘‘period’’ of (ut first) seven elements, and
then the eighth element shows a sharp change of properties from
those of the seventh and a striking resemblance to those of the
first ; the ninth resembles the second, the tenth resembles the third,
and soon. The first two periods consist of seven elements each ;
the subsequent ones, which are more or less complete, of seventeen
each, In the following Table the periods are arranged in perpen-
dicular columns, whereby kindred elements are to a large extent
brought side by side in the same horizontal lines :—
Tuble of the Elements, arranged to illustrate the Periodie Law,
K 33.86 Rb 84.5 Cs 131.9 one
Ca 39.8 Sr 66.94 Ba 1364 eee ai
Se 43.8 86.3 La 137.9 Yb 17L7 sae
» Th230
i 47.7 Zr 89.9 Ce 139.2
90.8 Ch 93.9 one
95.3 - W 182.6 U 236.7
Ta 181.6 és
100.9 . Os 189.6
102.2 * Ir 191.5
105.7 » Pt 19338
107.12 oo Au 195.7
111.6 . Hg 198.5
10.9 Al 26.9 Ga 69.5 In 113.1 « ‘T2086
11.91 81 28.2 Ge 71.9 Sn 118.1 . Pb 206,35
13,93 P 30.80 As 74.4 Sb 119.3 . Bi 2069
15.88 S 31.82 5e 78.6 I 125.9 sah a
18.9 Cl 35.19 Br 79.36 Te 126.6 + -
Tt will be noticed that there are gaps in the Table suggesting
elements yet to be discovered, or indicating uncertainty as to the
correct: position of a number of known elements; also that there
are irregularities suggesting the desirability of reconsidering some
of the present atomic weights. Other difficulties also occur, but
still the regularities are so striking as to show clearly that the
properties of the elements are in some way dependent on their
atomic weights.
The nature of some of the progressive relations to each other of
the members of the first two periods are illustrated by the formulme
of certain of their compounds when placed side by side, Where
blanks occur, either no compound at all, or no illustrative com-
pound, is known,
THE PERIODIC LAW.
Compounds with oxygen :—
iO GlO BO, ©o,
NaO MgO ALO, SiO,
Compounds with hydrogen :—
ee ee ee |e ee
ae ic =a Poe BELO
Compounds with chlorine :—
Licl Gicl,' BC Oc NC, oo, —
NaCl MgCl, Alcl, sick Po, scl —
The compounds formulated above are not the whole of the oxy-
gen, hydrogen, and chlorine compounds of the various elements,
but are chosen to illustrate regularities as far as possible. There
are, however, a number of irregularities in these periods, and in
the subsequent periods irregularities become more numerous,
Since the position of an element in the above Table is fixed by
its atomic weight, and since it has been found that the properties
of an element and the character of its compounds can be foreseen
to a certain extent from those of its neighbors in the Table, above
and below, right and left, the general statement has been enunci-
ated, based upon this periodic arrangement and supported by a
great deal of evidence, that the properties of an element and the
nature of its compounds are functions of its atomic weight,
An inspection of the foregoing Table shows how allied elements
are brought together in groups. Thus the halogens (with the
exception of iodine") all fall into one line, and the same is true of
the groups of kindred elements, calcium, strontium and barium ;
nitrogen, phosphorus, arsenic, and antimony ; ete. Further, each
of the first five periods is heated by an alkali-metal, The symbols
printed in black type are those for the small group of elements
usually classed as non-metals, and indicate the remurkable nature
of a position of these elements in the periodic system of clussifi-
cation,
. “Ie seems as if the true position of iodine in the periodic system should
be after instead of before tellarium. The respective places assigned to
iodine and tellurium depend, however, upon the determinations of the
atomic weights of these eloments which are considered to be the most
reliable,
ADVICE TO STUDENTS.
ADVICE TO STUDENTS RESPECTING THE
METHOD OF STUDYING THE FOLLOWING
PAGES ON ORGANIC CHEMISTRY.
Both medical and pharmaceutical students of organic chemistry
may be divided into two classes, namely ; junior afudents, or those
who, in the first instance at all events, desire to obtain only a
general acquaintance with the subject, and senior students, or those
who, having some general information, desire further knowledge
of this branch of the science. To the members of each of these
classes who use this Manual, some advice concerning the kind and
extent of work they may hope to accomplish in this department
of the science will perhaps be acceptable.
Junior Students. —The whole of the following section on organic
chemistry should be read through carefully once or twice, with
the object, not so much of remembering all that is stated, as of
acquiring (a) a general view of the scope of the subject, (6) aclear
notion of the modes of classifying organic substances, and (¢) an
intelligent perception of their broad relationship to one another.
Special attention should be given to the methods of preparing
and testing the particular substances officially recognized in the
Pharmacopoeia, the student of practical chemistry preparing actual
specimens of most of these substances, as well as studying their
analytical reactions and testing for impurities in them. He should
prepare small quantities of chloroform, iodoform, spirit of nitrous
ether, acetic ether, and a volatile oil ; should extract gum from a
grum-resin, purify some benzene, test aloin, and examine methy-
lated spirit of methy) alcohol ; prepare some alcohol by fermenta-
tion, concentrating the product until it will burn; make ether;
convert amy! alcohol into valerie acid ; test earbolic acid and gly-
verin ; manufacture a specimen of soap; extract mannite from
manna ; examine the analytical reactions of cane and grape sugars;
obtain starch from wheat-flour, maize-flour, and a potato, and
examine each product with the microscope ; make dextrin, proxy-
lin, and collodion ; prepare and test aldehyde, and try the action
of lime on chloral hydrate; prepare and test acetic, oxalic, and
citric acids ; emulsify sweet and bitter almonds : prepare elaterin,
and test jalap-resin and salicin ; extract morphine or quinine, or
both, and perform the tests for the chief alkaloids of opium, cin-
chona, and nux vomica; test albumin and pepsin, Having gone
through these operations, he should read again through the whole
section,
ADVICE TO STUDENTS. 367
Senior Students, having done all that junior students are, in the
previous paragraph, advised to do, should thoughtfully study every
page, reading what one other author, at least, has to say on each sub-
ject. More especially they should actually prepare, or test, or other-
wise experiment with, one or more typical members of most of the
series, or sub-series, of organic substances. For example, they
should prepare the hydrocarbon methane (from sodium acetate), con-
vert it into a Aaloid derivative (by one of the given methods), trans-
form this into the a/eohol (by the agency of silver oxide and water),
and this again into the acid (by oxidation), The preparation of ace-
tylene, and ethylene, and some of their derivatives, should be tried;
the differences between turpentine and petroleum spirit should be
experimentally proved ; nitro-benzene should be made, this be con-
verted into aniline, and this again into ‘‘ mauve’’; aloinshould be
prepared; methyl alcohol be extracted from crude wood spirit, and
absolute alcohol be obtained from “alcohol (92.3 percent.)” ;
alcohol and acetic acid should be regenerated from the acetic ether
previously prepared (by ebullition with a concentrated aqueous
solution of potassium hydroxide) ; ethyl iodide or bromide and per-
haps zinc-ethy] be made ; glycol be prepared and then oxidized ;
glycerin be examined ; starch be converted into dextrin and into
sugar; malt extract be examined for diastase ; trinitrocellulin be
made; acetaldehyde be fully examined and aldehyde-ammonia
prepared ; lactic acid be made; benzoic and salicylic acids and
aldehydes be obtained ; natural urea be extracted and an artificial
trea made ; the glucosides be examined ; and one or two artificial
alkaloids be prepared ; etc. Melting-points and boiling-points of
ure substances should be taken ; and fractional distillation should
applied either to acetic acid with a view to separate glacid acid
on the one hand from water or weak aqueous acid on the other, to
mixed aleohol and water with the object of attempting their
re-separation as far as possible, or to some such mixture. Especi-
ally must the operations of quantitative analysis of organic com-
pounds, in due time, be fully and thoroughly performed,
Other Students.—Students who have no occasion to apportion
their periods of study in the manner contemplated in the previous
paragraphs are recommended to go through the succeeding sections
as they have gone through the foregoing, namely, page by page.
ORGANIC CHEMISTRY.’
INTRODUCTION.
Wirn the exception of alcohol, some acids and their salts,
and a few other substances, the large number of compounds
which have hitherto engaged the student’s notice in this
Manual have been of mineral origin. But the two other
kingdoms of Nature, the animal and vegetable, furnish still
larger numbers of definite compounds. We shall now pro-
ceed to the consideration of these, the latter chiefly.
In its original signification what was termed Organic
Chemistry (épyavov, organon, an organ) embraced the chemistry
of those substances which were known only as products of the
vital processes which take place within the tissue of plants
and of animals; and, further, the chemistry of the various
products derived from these substances, or from the tissues
themselves, by subsequent treatment in the laboratory. The
separate classification and consideration of these substances
formerly seemed expedient in view of the fact that none of
them could then be obtained by the ordinary operatious of
the chemical laboratory, starting from non-organized materials.
The term “organic” as originally applied to any substance
was thus intimately associated with the view that organized
matter—living matter, or matter which had at one time
formed part of a living plant or animal—was necessary for
its production. Methods are now known, however, whereby
a considerable number of substances which are identica) in
every respect with known products of animal or plant life
(or with derivatives from these) can be prepared in the labo-
ratory “artificially,” as it is often termed, from purely jnor-
ganic materials.
'Students will find that in taking up the subject of organic chem-
istry they are not departing from the method of study hitherto pursued.
Hitherto they have concentrated attention on thechief elements, oneat
nw time; they are now about to investigute the compounds of oneof those
elements which possesses a greater range of combining powers than any
other that has been examined. Organic chemistry is the chemistry of the
element carbon,
O68
INTRODUCTION, 369
Organic chemistry has been defined in more recent times
as the chemistry of the compounds of carbon. There does
not, however, now seem to be any good reason for classing as
organic, the oxygen compounds and some other relatively
simple compounds of carbon, including many of the naturally
occurring mineral carbonates; more particularly as these
must, for the sake of completeness, be dealt with under the
heading of inorganic chemistry. It is thus impossible to fix
the bounds of inorganic and of organic chemistry respectively,
unless an arbitrary line is drawn, which shall mark a distinc-
tion that is wholly artificial, and is not founded upon any real
difference in the general nature of the facts and principles
treated of under the two headings, There is, in short, but
one science of chemistry, and the separate consideration of
the chemistry of the majority of the compounds of carbon is,
to a Jarge extent, a matter of convenience only. The very
great number of the compounds of carbon and the complexity
of many of them, together with the general readiness which
they usually exhibit to enter into new combinations, may be
mentioned as among the reasons for their separate study,
The one fundamental fact concerning every so-called organic
compound is, that it contains carbon as one of its constituents,
combined with oneor more other elements; but, as we have
already seen, every compound of carbon is not an organic com-
xound in any sense which it is convenient strictly to define.
course, so old and historically interesting a term as organic
chemistry will continue to be used ; and there is no objection
tosuch use, provided students remember that when the term is
used, it is only conventionally and not etymologically accurate.
Tt will be unnecessary to discuss again in what follows the
chemistry of those compounds of carbon which have already
been treated of in earlier parts of the Manual.
As instances of the formation, from purely inorganic
materials (or from products obtainable from inorganic
materials), of compounds which are generally classed as
organic, the following may be mentioned :—
(1) The formation of acetylene, C,H,, by passing electric
ks from carbon terminals in an atmosphere of hydrogen ;
and by the action of water on calcium carbide.
(2) The formation of potassium cyanide, KCN, by passing
nitrogen over a strongly-heated mixture of potassium and
earhon, or of potassium carbonate and carbou heated to the
temperature at which potassium is liberated (p. 72).
24
370 ORGANIC CHEMISTRY,
(3) The formation of marsh gas, CH,, by passing a mixture
of hydrogen sulphide and vapor or carbon bisulphide over
red-hot copper.
(4) The formation of urea, CO(NH,),, by the action of
ammonia on carbonyl chloride (phosgen ) ; and by evaporating
to dryness a solution of ammonium cyanate,
(5) The formation of potassium formate, KHCO,, by the
action of carbonic oxide on potassium hydroxide.
Elements which enter into the composition of organie Substancea,—
The elements which, beside carbon, are of the greatest impor-
tance from their entering most frequently into the composition of
organic substances are hydrogen, oxygen, and nitrogen. All the
naturally occurring organic substances contain carbon and hydro-
gen, associated almost always with oxygen, and often with nitro-
gen; some of them also contain sulphur or phosphorus or both,
in small quantity. Aniong artificially prepared organic sub-
stances, compounds have been obtained containing almost any of
the other known clements.
Detection of the various elements present in Organic Substances, —
It isnot intended here to give any detailed account of the analysis
of organic substances, but the general principles and a few im-
portant methods may advantageously be outlined.
In order to demonstrate the presence of combined carbon and
hydrogen in any substance, it is usual to burn a small quantity
of the substance in a current of pure dry air or oxygen in a hard-
glass tube closely packed for a part of its length with cuprie
oxide which is kept red-hot throughout the operation, The cur-
rent of air or oxygen enters at one end of the tube and the
gaseous products of combustion pass out at the other. During
the process the carbon and hydrogen of the substance are com-
pletely oxidized—the former into carbonic anhydride and the
latter into water—and the presence of the two elements is indi-
cated by the formation of these respective products. This process
can be made A method of quantitative analysis, since, by collecting
and determining the weights of the two products obtainable from
a known weight of the organic substance, data are obtained from
which the proportions by weight in which the two elements are
present in the substance can be calculated.
The presence of nitrogen in an organic substance is detected by
strongly heating a few grains of the substance in a test-tube with
a small piece of metallic sodium, grinding up the fused mass with
water, filtering, and examining the solution for the presence of a
dissolved cyanide. In the process the nitrogen of the substance,
along with some of ‘the carbon, combines with the sodium to form
sodium cyanide, NaCN; and the observation that a cyanide has
been formed is a proof of the presence of nitrogen in the sub-
INTRODUCTION. 371
stance. Part or the whole of the nitrogen of some (but not of all)
organic substances is evolved us ammonia when the substance is
moderately heated in a test-tube with soda-lime.’ The quantita-
tive determination of nitrogen is effected by various methods, but
the only one which need be mentioned here is analogous to that
employed for the determination of carbon and of hydrogen. <A
weighed quantity of the substance is heated in aslow current of
carbonic anhydride in 4 glass-tube containing cupric oxide which
is heated red-hot. The nitrogen is liberated either as such, or in
the form of gaseous oxide of nitrogen, Before emerging from the
tube the mixture of gases passes over a quantity of red-hot copper
wire-gauze, tightly packed. The latter retains any free oxygen
by combining with it to form cupric oxide, and also decomposes
the oxides of nitrogen, similarly retaining the oxygen of these
while the liberated nitrogen passes on. The carbonic anhydride,
water vapor, and nitrogen which emerge are passed into a gradu-
ated tube containing a concentrated solution of potassium hydrox-
ide, Thecarbonic anhydride is here absorbed forming potassium
carbonate, the water vapor condenses to form liquid water, and
the pure nitrogen is collected and its volume is measured, From
the observed volume, under the conditions of temperature and of
pressure which has also been noted, the weight of the evolved nitro-
gen can be calculated.
The presence of oxygen in a non-volatile organic substance can
usually be detected by simply heating the dry substance in an
atmosphere free from oxygen, and observing the formation of
water, The oxygen necessary for the production of water, in
such a case, must have been present in the substance under ex-
amination, The direct quantitative determination of oxygen
presents considerable experimental difficulties, and no satisfactory
method for making this determination has come into general use,
It is usual in actual practice to determine the quantities of all the
other elements present in a given weight of the substance and
then to regard the remainder as the quantity of oxygen,
In order to detect sulphur or phosphorus in an organic sub-
stance, the latter is, in most cases, first oxidized by some suitable
process, and the oxidation products are then examined for the
presence of sulphuric or phosphoric acid. The quantitative deter-
mination of these elements also usually requires oxidation as a
preliminary,
The detection and quantitative determination in Wrganic sub-
stances of other elements, such as chlorine, bromine, iodine,
metals, ete., require in general the oxidation of the substance or
the decomposition of it by some other process, and the subsequent
examination of the products of such operations by the methods
'The product obtained by slacking quicklime with a solution of sodium
hydroxide.
372 ORGANIC CHEMISTRY.
of qualitative and quantitative analysis applicable to inorganic
substances,
General effects of Heat upon Organic Substances.—The effects
produced by heating various organic substances vary greatly in
the cases of different compounds. We shall briefly consider
the general effects (1) when organic substances are heated by
themselves, that is, out of contact with anything more than small
quantities of air; and (2) when they are heated with free access
of wir.
(1) Solid organic substances when heated may simply become
liquid, and the liquid so produced may, on being further suffi-
ciently heated, boil and be completely volatilized without under-
going any decomposition, Glacial acetic acid and acetamide are
examples of such substances. Other solid substances may simil-
urly become liquid, but the liquid on further heating may decom-
pose before the temperature of volatilization has been reached,
This is the case with cane sugar and with urea. Other solid sub-
stances again, such as starch and cellulose, cannot be liquefied by
heating them because the temperature at which decomposition
takes place*lies below the temperature of liquefaction. Substances
belonging to these last two classes very commonly yield on
decomposition by heat a quantity of volatile products (some of
which are gaseous and others liquid at ordinary temperatures) and
leave behind in the vessel in which the decomposition has taken
place, a highly carbonaceous, non-volatile black residue or char-
coal. Charcoal suitable for special purposes is often prepared by
thus heating starch, sugar, cellulose, etc. When non-volatile
organic substances are subjected to this treatment the process is
called dry or destructive distillation. Such processes are carried
out on a very large scale with wood, with coal, and with different
kinds of shale, and form a part of several important manufactur-
ing industries.
Of organic substances which are liquid at ordinary tempera-
tures, a very large number, such as common alcohol and ether,
are capable of volatilization without decomposition, while others,
such as glycerin, decompose at temperatures below their boiling
points, Substances which belong to this latter class cannot
therefore be distilled without decomposition, at least under ordi-
nary pressures. In some instances it is found possible, by
diminishing, the pressure inside the distilling apparatus, to lower
the boiling point of the liquid to a temperature below that at
which decomposition takes place and so to ensure its distilling
undecom posed. )
Organic substance which are gases at ordinary tempernta
and the vapors of organic substances which are solids or liquids
under these circumstances but which volatilize undecomposed,
may be exposed to the action of high temperatures by slowly
INTRODUCTION. 373
passing them through heated tubes. Under this treatment some
decompose readily, while others do not undergo any, or at least
any considerable, change. A method frequently made use of for
very rapidly heating a vapor, is that employed in the manufacture
of ‘‘ oil gas’’ from paraffin oil. The liquid oil is allowed to drop
on a red-hot metal or brick surface, when the vapor which is at
first produced becomes very strongly heated before it has time to
diffuse away from the hot surface. In this way the paraffin oil is
decomposed, yielding some coke and combustible gases which do
not become liquid again at ordinary temperatures. This operation
is technically called ‘‘ cracking’’ the hydrocarbonsof which the
paraffin oil is composed.
(2) When organic substances are strongly heated in suitable
forms of apparatus with free access of air, they usually undergo
complete oxidation, so far, at least, as their carbon and hydrogen
are concerned. These elements become converted into carbonic
anhydride and water respectively. Whena salt of any of those
organic acids which contain carbon, hydrogen, and oxygen only,
is subjected to this treatment, the carbon may either be com-
pletely driven off as carbonic anhydride, or a part may remain
combined in the form of a carbonate. The metal of the salt may
remain behind either as meta! (silver, platinum, etc.) or as oxide
(lead oxide, zine oxide, ferric oxide, etc.) or as carbonate (potas-
sium carbonate, barium carbonate, etc. ).
Distiliation.—The purification of organic substances is often
effected by distillation, as, forexample, when a volatile substance
is impure from the presence of any non-volatile admixture, The
separation of alcohol by distillation from the non-volatile constit-
uents present in the liquid of the fermenting tunis an instance of
this kind (p. 420).
A mixture of two or more liquids (all of them volatile, but of
different boiling points when pure and unmixed) may be more or
less completely separated by ‘“‘/ractional distillation ’’ —that is, by
separately collecting the portions of the distillate (‘‘ fractions” as
they are called) which disti] at different temperatures, or rather,
within certain intervals of temperature. Such fractions do not,
as a rule, consist entirely of one single liquid, but generally con-
tain some of the other volatile substances present in the original
mixture. By subjecting each original fraction to a second frac-
tional distillation, and systematically carrying out the same process
on succeeding fractions for several times, fractions of almost con-
stant boiling point, and composed almost entirely of one liquid
can in many instances be obtained; but in some cases nothing
more than a very partial separation can be effected, Thus from
a mixture of alcoho! and water it is not possible by distillation
alone, to obtain alcohol containing less than about 5 percent,
of water.
O74 ORGANIC CHEMISTRY.
Classes of Organie Compounds.—The majority of organic com-
pounds are conveniently grouped into two main classes, which are
known as the Fatty (or Aliphatic), and the Aromatic classes
respectively. When these names were first employed, only a
comparatively limited number of organic compounds were known,
The natural fats gave rise to a number of representatives of the
first-class, which may all be regarded as derivatives of methane,
CH,; a considerable number of representatives of the second
class, which may be regarded as derivatives of benzene, O,H,, are
more or less aromatic substances, such as some of the essential
oils, ete. The words fatty and aromatic are of historical interest,
but although in common use, they cannot now be looked upon as
very appropriate. In dealing with the fatty or aliphatic and the
henzene or aromatic compounds, these two classes will only be
considered separately in so far as a moderately systematic treat-
ment may seem to require.
Constitution or Structure of Organie Compounds,—The problem
of the relations to one another of the various atoms which com-
pose a molecule, is one which early attracted the interest and
attention of chemists; and it is one for the solution of which
materials have been accumulated slowly and laboriously from the
synthetical and analytical investigation first of the simpler and
afterward of the more complex chemical compounds, inorganic
and organic. How to recognize the presence of certain groups of
atoms, or radicals, in the molecules of chemical substances, and
how to find out the position of these groups in the molecules is
often a most difficult and yet a most fascinating task for the
enthusiast and skilled experimentalist in chemistry ; and how to
so marshal these groups (drawn perhaps from several different
sources, and obtainable only in a state of combination) that he
shall produce by art the compound originally only furnished by
nature, is still more difficult, but also more fascinating.
More fascinating firstly, because it will furnish proof that
his synthetical work was sound; secondly, because by artificially
and perhaps cheaply producing a rare color, a rare perfume, a rare
flavor, or a previously costly medicine, he may become a bene-
factor to his fellow-man; and thirdly, because he may gain the
honor of unveiling for all time one more of the truths of nature,
In practically attacking the problem of the constitution ofa
compound, the chemist proceeds to note whether the substance is
acid, alkaline, or neutral ; to act on it with a base of known con-
stitution if it is an acid, or with an acid of known constitution if
it isa base, and to analyze the produced salts; to oxidize it ; to
deoxidize it; to heat it; to electrolyze it; to chlorinate it; to
remove or add hydroxyl (OH), carbonyl (CO), etc. ; to substitute
hydrogen by a compound radical, and vice verad ; and, generally,
to perform many such operations, in the hope that the lines of
chemical cleavage in the molecule will be detected, the essential
INTROD UCTION,. afd
groupings of atoms in the molecule be discovered, and even the
positions of atoms or groups of atoms in relation to each other be
reasonably inferred. Briefly, similarity in properties implies
similarity in constitution or structure. Jer contra, similarity in
structure being reasonably implied, reference to properties shows
whether or not the reason is on the right track toward truth in
the mutter of constitution or structure, the advance toward error
being prevented and toward truth being maintained whatever be
the result of the reference, new truths not infrequently being
unveiled. Thus, by the way, in chemistry, do fact and theory
ever discharge their obligations to each other.
. Notation of Organic Compounds,—tIn order that we may convey
toone another our conclusions respecting the constitution of
organic compounds, notation has to be carried somewhat farther
in organic than is as a rule necessary in inorganic chemistry. The
relative positions of atoms and groups of atoms in a molecule may
be indicated by placing the symbolic letters above or beneath one
another as well as on one line, and the quantivalence of atoms, as
well us the ways in which we conclude they are linked in the
molecule, may be indicated by lines (—= —) or dots(. : +)
either completely or only partially employed throughout the for-
mula ; each dot or line or ‘‘link,"’ or “‘bond,’’ representing the
supposed condition of union between two neighboring atoms or
radicals, Formule which, by the aid of such dots or lines, pur-
port to represent the relative positions of the atoms and groups of
atoms in molecules (7. ¢., to represent the constitution or structure
of the molecules) are called constitutional or structural formula,
Many examples of such formule will be met with in the sueceed-
ing pages of this Manual. When structural formule are written
in the most extended form, so as to represent by the aid of lines
the way in which every atom in a molecule is united to its adja-
cent atoma, the resulting formule are often called graphic formula,
QUESTIONS AND EXERCISES.
What do you understand by organic chemistry ?—Give methods of
ascertaining the presence of carbon, hydrogen, and nitrogen In organic
componnds.—Give an outline of the methods by which the quantities of
earbon, hydrogen, oxygen, and nitrogen are determined in organic com-
pounds.—What is meant by “fractional” distillation ?—Name two of the
chief classes into which organic compounds are divided.—How is the eon-
stitution of an organic compound ascertained ?—What do you understand
hy constitutional or structural formule ?—What are graphic formule?
HYDROCARBONS,
Compounds known as hydrocarbons contain the elements
hydrogen and carbon only, and are exceedingly numerous. A
376 ORGANIC CHEMISTRY.
very large number of the known hydrocarbons belong to the fatty
class, three of the chief groups being the Paraffin, the Olefine, and
the Acetylene series,
THE PARAFFIN SERIES OF HYDROCARBONS.
Of all the known hydrocarbons, the simplest in composition is
methane or marsh gas, which is the first member of the series
called Paraffins. In this series of hydrocarbons (and in it alone)
the total combining capacity of each carbon atom is sutisfied in
such a manner (either by linkage with hydrogen atoms, or with
other carbon atoms, or, as is almost always the case, by linkage,
partly with hydrogen atoms and partly with other carbon atoms)
that the members of the series are not capable of entering into
direct union with chlorine or bromine, so as to form additional
compounds, Hence the series of paraffins is often called the series
of saturated hydrocarbons. Methane is the only hydrocarbon
which has the total combining capacity of its carbon satisfied by
linkage with hydrogen atoms. Its composition is represented by
the formula CH,
H
|
or H—C—H.
i
If we suppose one hydrogen atom of methane to be removed and
its place to be taken by the group—CH, (which is called methyl),
we get the composition of the next simplest paraffin, ethane,
C,H,. There is no reason to suppose that any one of the four
hydrogen atoms of methane differs in the least from any of the
others in the way in which it is related to the carbon atom and to
the other three hydrogen atoms, Thus on considering in the
H
graphic formula H—C—H, the relations of any particular
i . s
hydrogen atom, we see that it is linked to a carbon atom which in
turn is linked to three other hydrogen atoms. Accordingly it is
immaterial which of the four hydrogen atoms we suppose to
replaced by the methyl group, because, if the relations of all four
are similar, there would in any case result the substance ethane,
H H
he “HH. Ethane is also a paraffin (the second of the
LJ
H H
PARAFFINS.
series) and contains two carbon atoms, each of which is linked
one-fourth to carbon and three-fourths to hydrogen,
But just as in methane any one of the four hydrogen atoms is
related to the single carbon atom in the same way as any other,
so in ethane, any one of the six hydrogen atoms is related to one
of the carbon atoms in the same way as any other is.
Thus on considering, in the graphic formula for ethane just
given, the relations of any one of the six hydrogen atoms, we sce
that it is linked to a carbon atom which is in turn linked to two
other hydrogen atoms and to the group—CH,. The relation of
each hydrogen atom to what is called the ‘‘carbon nucleus,’’ in this
case C—C, is the same. Hence if we suppose one hydrogen atom
of ethane to be removed and its place to be taken by the group—
CH,, it is immaterial in this case also which of the hydrogen atoms
we suppose to be thus replaced. The resulting compound is pro-
pane, C,H,, the third hydrocarbon of the paraffin ag asi
|
eration of the graphic formula of this substance, H—-b-G-O-8.
hk h
reveals the fact, however, that all of the hydrogen atoms are no
longer similarly related to the carbon nucleus, C—C—C. Each
hydrogen atom is linked to a carbon atom as before, but while six
of the hydrogen atoms are linked to the two end carbon atoms,
which besides are one-fourth linked to carbon, the two remaining
hydrogen atoms are linked to the central carbon atom which is
one-half linked to carbon. The eight hydrogen atoms in propane
ire thus divisible into two groups, consisting of six and of two
respectively, according to the position in the carbon nucleus of the
carbon atoms to which they are linked. If then, we suppose one
hydrogen atom of propane to be removed, and its place to be taken
by the group—CH, it may not any longer be immaterial which
atom we suppose to be thus replaced. The resulting compound
will in any case have the composition, C,H,,, but it is evident that
two different arrangements of these atoms are possible as indicated
by the formule :-—
HH H H H H Hu
|
(1) ah 4-dd_n and (2) 1-o-d-0-8. The for-
bon, i
hia k Hon,
mula (1) would represent the arrangement in the case of the
replacement of an end hydrogen atom of propane by—CH, ; the
formula (2) that in the case of the similar replacement of a central
hydrogen atom. As a matter of fact, two (and only two) paraflins
aire known, both with molecular weight corresponding to the
formula, C,H,,, but differing from each other in properties. The
378 ORGANIC CHEMISTRY.
formula (1) is assumed to represent one of these two compounds
which is called normal butane, and the formula (2) to represent
the other which is called isobutane.
Although it is beyond our present intention to follow much
further the possible varieties in the constitution of the compounds
which we may regard as derived from ‘lower’’ paraffins (i, ¢.,
parattins containing in their molecules a smaller number of carbon
atoms) by the replacement in these of different hydrogen atoms by
the methyl group; it may be well to proceed here one step further
in this direction in the cases of norma! butane and isobutane, both
of which we may regurd as derived, by this kind of replacement,
from propane.
Thus on considering the hydrogen atoms of normal butane (for-
mula (1) above) it is seen that six of them (the two end sets of
three each) are linked to two carbon atoms which in turn are one-
fourth linked to carbon and are both related in the same way to
the carbon nucleus, while the remaining four (the two central sets
of two each) are linked to carbon atoms which in turn are one-
half linked to carbon and are both related in the same way to the
carbon nucleus, but that any one of the six has got the same kind
of relations to the remaining atoms in the molecule as any other
of the six has, and that any one of the four has likewise got the
same kind of relations to the remaining atoms in the molecule as
any other of the four has. From normal butane then, if we sup-
pose one hydrogen atom to be replaced by the methyl group, it is
conceivable that two different substances might be derived, one of
which would be represented by the formula—
H HHH A
Via Wi stag
—C—C—C—H, and the other by the formula
H H H FA
Pe a
H or H—C—C—C—(_H,,
| YA Wi,
H ch, H H H H ott, tt
But on considering the hydrogen atoms of isobutane (formula
(2) above) it is seen that nine of them (three sets of three exch)
are linked to three carbon atoms which in turn are one-fourth
linked to carbon and are all related in the same way to the
carbon nucleus, while the remaining one is linked to a carbon
atom which in turn is three-fourths linked to carbon and differs
from all the others in its relation to the carbon nucleus. The
relations to the remaining atoms in the molecule, of any one of
the series of nine hydrogen atoms are of exactly the same kind as
PARAFFINS. 379
those of any other of them, and the relations of each of them are
different from those of the single hydrogen atom. Here again
then, if we suppose one hydrogen atom of isobutane to be replaced
by the methyl group, it is conceivable that two different sub-
stances might be derived, of which one would be represented by
the formula—
WfHUH H HH H H H H H
CR ae | | ae
H—C —C—H or a ee or aah ie kh ia
i
—H
“teed = okt
H
H | H H—C—H
\ IZ
HCH H
and the other by the formula no bb oy
i
ay
H | H
H
But comparison of the formula given for the second of the con-
ceivable derivatives from normal butane with that given for the
first of the conceivable derivatives from isobutane shows that these
two are identical, and that therefore there wre theoretically only
three paraffins of the formula C,H,, derivable from the two butanes
by the replacement of one hydrogen atom by the group—CH,.
As a matter of fact three paraffins (and only three) are known all
with molecular weight corresponding to this formula. They are
called pentanes and they differ yery considerably from one another
in their properties.
Tsomeriam, Polymerism, Metamerism.—The occurrence of two
or more substances possessing the same centesimal composition but
differing in properties, as exemplified in the cases of a number of
the paraffins mentioned in the foregoing paragraphs, is very fre-
quently met with, especially in organic chemistry, Substances
which stand in this relationship to each other are termed isomeric
from lows, ixos, equal, and pépoc, meros, part) ; and their condition
spoken of as one of isomerism, There is sometimes good reason
for doubling or otherwise multiplying the formula of one of two
isomers, isomerides, or isomeric substances. Thus a molecule of
ethylene (olefiant gas), one of the chief illuminating constituents
of coal gas, is represented by the formula C,H,, while a molecule
of butylene, a hydrocarbon having the same percentage composi-
tion as olefiant gas, is represented by the formula C,H,, because
butylene in the state of gas is specifically twice as heavy as ethy-
380 ORGANIC CHEMISTRY.
lene, and must contain, therefore, in each molecule, twice as
many atoms, since (Avogadro) equal volumes of the substances in
the gaseous state and under the same conditions contain equal
numbers of molecules ; its formula is, consequently, fixed in con-
formity with these facts. This variety of isomerism is termed
polymerism (from rodic, polis, many or much, and pépoc, part).
Formaldehyde, CH,O, acetic acid, C,H,O,, and lactic acid, C,H,O,,
furnish another group illustrative of polymerism. Metastannie
acid (see p. 195) is a polymeric variety (polymer or polymeride) of
stannic acid, An example of another variety of isomerism is seen
in the case of ammonium cyanate and urea, substances already
alluded to in connection with cyanic acid. These and several
other pairs of chemical substances have dissimilar properties, yet
are similar in the centesimal proportion of their elements, and we
cannot avoid the conclusion that each molecule possesses the same
number of atoms. But the reactions of these substances indicate
their probable constitution ; and this is represented in their for-
mule by the disposition of the symbols, Thus ammonium cyanate
is represented by the formula NH,CNO, urea by CO(NH,),. Such
substances are termed matameric (from jperd, mela, a preposition
denoting change, and pépoc), and their condition spoken of as one
of metamerism, Ethyl acetate (p. 403) is metameric with butyric
acid (p, 453); they have the same percentage composition and the
same vapor density and each might be represented by the formula
C,H,0O,, ; but their properties warrant us in assuming that their
atoms occupy different positions in the two molecules—justify us
in writing CH,.COOC,H, as the formula for a molecule of ethyl ace-
tate, and C,H,.COOH as the formula for a molecule of butyric
acid. Methyl acetate, CH,,COOCH,, propionic acid, C,H,,COOH,
and ethyl formate, H.COOC,H,, are isomers of the metameric
variety, or mefamers or matemerides * also quinine and quinidine,
cinchonine and cinchonidine, many of the volatile oils, ete.
Homologous Series.—In the consideration, so far, of the series of
paraffins, we have seen that, starting from the first member,
methane, each succeeding member of the series differs from the
one which immediately precedes it by containing the grou
in the place of an atom of hydrogen ; or, in other words, by the
common difference of one atom of carbon and two atoms of hydro-
gen (CH,). Many other series of substances besides the paraffins
are known in which the successive members differ from one another
by CH,, or a multiple of CH,. Such series are called Aomolo
(from éudc, homos, the same, and Adyor, logos, proportion), The
‘‘higher’’ members of the paraffin series (i. ¢., those containing
in their molecules more than one atom of carbon) are called Aomo-
loques of methane.
General formula for homologous series.—It is often convenient
(and it is always possible) to represent the general composition of
the members of any homologous series of compounds by means of
PARAFFINS, 381
a formula. In the case of the paraffins the general formula is
usually written C,H,,',., where » represents the number of carbon
atoms in a molecule of the compound. This formula shows that
whatever number of carbon atoms a molecule of the paraffin con-
tains, it contains twice that number of hydrogen atoms and two
hydrogen atoms besides. The general formule for some other
homologous series will be given later in their respective places,
Normal Paragiins,—The term normal is applied to those paraflins
in which the carbon nucleus is capable of being represented as
consisting of carbon atoms so linked together as to form a single
‘*chain’’ without any ‘‘side-branches’’ (or “side-chains’’) ; for
example, C—C as in ethane, C—C—C as in propane, C—C—C—C
a3 in normal butane, C— C—C—C—O as in normal pentane, It
will be observed that in these “‘chains” the carbon atoms are
represented as either one-fourth or one-half linked to other carbon
atoms, but never more than this, Contrast these straight ‘‘chains’’
with C—C—O, the carbon nucleus of isobutane, and with
f C
C—C—C—C and C— bo those of isopentane and of tetra-
( '
methyl methane respectively, in the first two of which one carbon
atom of each is represented as three-fourths, while in the last, one
carbon atom is represented as wholly linked to other carbon atoms,
Carbon atoms which may thus be distinguished in the carbon
nucleus by the different proportion of their combining capacity
which is satisfied by linkage with other carbon atoms, are
designed as primary, secondary, tertiary, or quaternary, accord-
ing as one-fourth, one-half, three-fourths, or the whole of that
combining capacity i is so satisfied.
In connection with these designations of carbon atoms it is not
unimportant to note that the carbon atom in methane is not linked
to other carbon atoms at all but to hydrogen atoms exclusively;
and that, with respect to this peculiarity of its carbon atom,
methane is quite exceptional and differs from all other hydro-
carbons.
Occurrence of Parajfins in Nature. —Methane or marsh gas
occurs as a product of the slow decay of vegetable matter in
presence of much water, as, for example, in stagnant pools,
marshy places, ete,, and also as the ‘‘ fire-damp’’ of coal mines,
Further, methane and several of its homologues are present in the
gases which issue from the earth in the petroleum region of Penn-
syivania and in other parts of the world; while the crude petro-
leum itself which flows, or is pumped, from the earth in these
places, also consists of or contains higher members of the series.
Formation of Paraffina in the dry distillation of coal, wood,
shale, ete,—The volatile products obtained by the dry distillation
ORGANIC CHEMISTRY.
of these substances always contain considerable quantities of par-
affins. Thus methane is a constant constituent, in large propor-
tion of coal gas and of wood gas. Further in the dry distillation
of shale in the Seottish ‘ paraffin oil’’ industry, besides the
paraflins which are contained in the gaseous products, the liquid
(listillate consists largely of liquid paraffins in which solid com-
pounds, also belonging to the paraffin series are held in solution.
Methods for the preparation of Paraffins.— It may now conven-
iently be shown that the process discussed on pp. 385-387 of
building up, from one member of the paraffin series, the next
higher member, by the replacement of a hydrogen atom by the
methyl group, 1s in certain instances capable of actual experi-
mental realization, This synthesis can be effected by several dif-
ferent methods, and one or two of these methods may be described
here with some detail.
1, One hydrogen atom of methane can, without difficulty, be
replaced by chlorine, methyl chloride, CH,Cl, being produced
(p. 396). From methyl chloride the corresponding iodine com-
pound (methyl iodide, CH,T) could be obtained. One way to do
this would be to convert the mythy! chloride into methyl aleohol,
CH,OH (p. 418), and from this to prepare methyl iodide. It is
indeed usual to prepare methyl iodide from methyl alcohol
(p. 398), but methyl alcohol is prepared on the large scale by
other methods (p, 418) very much more easily and cheaply than
would be possible ifit had to be obtained from methane by way
of methyl chloride, This method is stated here, however, in
order to show that the end in view, viz., the proportion of
methyl iodide starting from marsh gas, is capable of attain-
ment,
If methyl iodide, however prepared, is dissolved in a suitable
solvent, such asether, and the solution is treated with metallic
sodium, a reaction takes place which may be diagrammatically
represented thus :—
a en
ee ra
[ : |
[
H
The products are, sodium iodide (2Nal) and ethane,
H H
Areal
H—C—C—H,
H H
and the mode of its formation here furnishes strong evidence
concerning the constitution of ethane.
By carrying out a series of operations analogous to those de-
PARAFFINS. 353
acribed in the case of methane, only starting from ethane instead,
it is possible to prepare a derivative from this latter hydrocarbon
also, in which the place of one atom of hydrogen is taken by
iodine so as to form ethyl iodide, C,H.I. On the large scale ethyl]
iodide is, however, always prepared from ethyl! alcohol, C,H,OH
(p. 898) in the same way that methyl iodide is prepared from
methyl alcohol. If ethyl iodide is dissolved in pure ether and the
solution is treated with metallic sodium,a reaction takes place which
is exactly analogous to that represented above methyl iodide :—
methyl iodide :—
CH,CH,I 2Na 1CH,CH,,
whereby normal butane is produced ; while if the operation is
similarly carried out, but with the employment of a mixture of
methyl and ethyl iodides instead of ethyl iodide alone, besides
ethane and normal butane (which may both be supposed to be
formed according to the actions already represented above), a
quantity of a third paraffin, propane, C,H,, is always sands:
The formation of this paraiin may be represented thus :—
CH, I 2Na 1CH ,CH,.
Besides by the method ileoaty described for obtaining normal
butane from ethyl iodide by the action of sodium, this paraffin
can also be prepared (mixed, however, with ethane and normal
hexane, ©, H,,), by a method strictly analogous to that just
given above for the preparation of propane, only employing a
mixture of methyl iodide and normal propyl iodide, C,H1,,'
instead of the mixture of methyl and ethy! iodides,
Thus by two variations of the same method, t.¢., by acting with
sodium (a) upon solution of a single iodide, and (4) upon mixed
solutions of two different iodides, normal paraffins can be obtained
either with even numbers of carbon atoms in their molecules, or
with odd numbers (greater than one), It must be noted, however,
that when mixed iodides are employed, a mixture of three different
paratiins is always obtained, as illustrated above, and even the
approximate separation of these from one another may not be
practicable. A reaction ofthis kind cannot, therefore, be employed
as 4 mode for preparing a single paraffin in a state of purity.
'The iodides are known, both with molecular weight corresponding to
the formula CsH;I. They are called normal and iso-propy! iodides,
H H H
=. ‘nal ores
ond may be represented by the formule H—C— C— C—I and
H H H |
yet
. H H H
H— hed — bo H respectively,
i k
584 ORGANIC CHEMISTRY.
2. Paraffins are obtained (along with other products) by the
electrolysis of solutions of potassium salts of the homologous series
of acids to which acetic acid belongs. These acids are all re,
as containing a group of atoms which is called the pris ox:
and is supposed to consist of a carbon atom with its com
capacity three-fourths satisfied by linkage with two oxygen atoms
(i.¢., one-half by linkage with one oxygen atom which is thereby
fully satisfied, and one-fourth by linkage with a second oxygen
atom which, in turn, is further linked to a hydrogen atom ‘The
constitution of this group may be represented graphically thus:
O
l
—C—O—H. To save space, however, it is often printed—COOH.
In the acids of the acetic series (and in carboxyl acids generally)
the carbon atom of this carboxyl group is supposed to be further
one-fourth linked to another carbon atom in the molecule (with
the single exception of formic acid, the first member of the acetic
series, in which the carbon atom of the carboxyl group is the only
one contained in the molecule and is supposed to be one-fourth
O
I
linked to a Aydrogen atom thus : H—C—O—H).
The composition of any member of the acetic series of acids may
be represented by the general formula C\H,,O,, or better by the
more extended formula C,H,,,,,;COOH. The consideration of
this latter mode of writing the general formula for these acids
shows that the acids themselves may be regarded as paraffins
(C,H,,,2) from which one hydrogen atom has been removed (leaving
C.H,,,,), the place of this hydrogen atom being taken by the car-
boxy! group. It is in this light that we shall regard these acids
for our present purpose.
The formation of various paraffins by the electrolysis of solutions
of the potassium salts of acids of the acetic series may be illustrated
by the following example :— , sean
When a concentrated solution of potassium acetate, CH,COOK,
is electrolyzed, it may be represented that the salt is first separates
into potassium and the acid radical of the acetates and that other
changes follow. Thus there are formed :
At the Cathode | At the Anode
K CH,COO
which interacts with water, | which breaks up forthemost part
yielding KOH and H. The into—CH, and CO, (although
H atom then unites with an- other changes oecur lo some ex-
other H atom, similarly pro- tent), Each —OCH, group then
duced, to form a hydrogen mole- | unites with another—CH, group,
cule, H,, similarly produced, to form an
ethane molecule, C,H,
PARAFFINS. 385
3. Another method for the preparation of paraffins, which is of
somewhat general applicability, consists in heating the salts of the
acids of the acetic series with basic hydroxides. The basic hydrox-
ide, at a high temperature, removes carbon and oxygen from the
salt in the proportions in which these elements combine to form
carbonic anhydride, a carbonate and a paraflin resulting from the
interaction. It has been found that the best results, on the whole,
are obtained by employing the barium salts and heating these with
barium hydroxide, Writing the general formula for the barium
salt (in which the bivalent atom of barium must of course be
represented as taking the places of two hydrogen atoms, i, ¢., of
one each in two molecules of the acid) the change which occurs
may be represented diagrammatically as follows :—
or by an equation as follows :—
(C,H,,,,COO),Ba 4+ Ba(OH), = 2BaCO, + 2C,H,,,
METHANE, . Marsh gas. Light carburetted hydrogen, Methyl
hydride. Fire‘damp. CH » This gaseous hydrocarbon may be
made from its elements by combining the carbon with sulphur to
form carbon bisulphide and the hydrogen with sulphur to form
hydrogen sulphide, and then passing these two compounds over
red-hot copper. It occurs naturally in coal mines and in the mud-
volcanoes of the Crimea ; it is frequently associated with the crude
petroleum that issues from the earth, and, mixed with carbonic
anhydride and nitrogen, is constantly rising in bubbles to the sur-
face of stagnant pools in marshy places. ‘It is a non-illuminating
constituent of ordinary coal-gas. It may be prepared by heating
with a mixture of 2 parts of dry sodium acetate, 3 of lime, and 2
of sodium hydroxide or, better, potassium hydroxide.
OH,COONa + NaOH = CH, + Na,CO,
Sodium acetate Sodium hydroxide Methane Fodium carbonate
Methane prepared in this way is never quite pure, but is mixed
with other gases of which the principal ones are hydrogen and
ethylene (p. 392), Pure methane is obtainable by the action of
water on zinc methide, Zn(CH,), -—
Zn(CH,), + 2H,O = Zn(OH), + 2CH,
386 ORGANIC CHEMISTRY.
Methane is a colorless and odorless gas of sp, gr. 8.07. Ttonly
dissolves to a small extent in water but is rather more soluble in
alcohol, It can be condensed to the liquid state by the applica-
tion of a moderate pressure at a very low temperature. It burns
in air, but, when pure, with a practically non-luminous flame :
CH, + 20, = CO, + 2H,0.
Mixtures of methane and air in suitable proportions give rise lo
violent explosions when fired. This occurs occasionally in insuffi-
ciently ventilated coal mines. About ten times its yolume of air
are required for the complete combustion of any given volume of
methane, When methane is mixed with eighteen times its volume
of air (or more than this) the mixture does not explode on the appli-
cation of a light.
ETHANE, C,H, Dimethyl. Ethyl hydride, —This 1s one of the
constituents of crude petroleum. It is usually prepared in quantity
by the electrolysis of a concentrated solution of potassium acetate
(p. 384). The mixture of ethane and carbonic anhydride which
is given off at the positive electrode during this process is made to
bubble through a concentrated solution of potassium hydroxide
which absorbs the carbonic anhydride, while the ethane passes on
unabsorbed,
Ethane is also obtained (a) by the action of sodium upon methyl
iodide dissolved in ether (p., 382), 2CH,1-4+2Na=2Nal+ C,H, ;
(4) by the action of water upon zine ethide, Zn (C,H), +,H,O =
Zn(OH), +- 2C,H, ; and (ec) by the interaction of zinc methide and
methyl! iodide : Zn(CH,), 4+ 2CH,I = ZnI, 4- 2C,H,.
Ethane is, like methane, « colorless and odorless gas. Its sp.
gr. is 14.95. Water dissolves less than one-tenth pf its volume of
ethane, but alcohol dissolves somewhat more than its own volume
of it. It can be condensed to the liquid state, at about 0°C., by
the application of moderate pressure. It burns in air with a very
feebly luminous flame :
20,H, + 70, = 4CO, + 6H,0
PROPANE, methyl ethyl, CSH,.—This gus, like methane, occurs
dissolved in the Pennsylvania petroleum springs.
Buranes, C,H,,.—As already stated, there are two isomeric
butanes, normal butane or diethyl, C\H,.C,H,, found in petroleum,
and tobufane or trimethyl methane, CH(CH,),, formed by artifical
Mena,
PENTANES, C.H,,.—As previously stated, three varieties are
possible, and three only are known, Ordinary amyl aleohol and
valerie acids nre derivatives of isoamyl hydride or isopentane.
Hexanes, C.\H,,.—Five are possible, five are known.
Hepraxes, (.H,,.—Nine are possible, five are known,
OCTANES, CH... Eighteen are possible, three are known.
Nonane, C,H,,, Decanr, ©,,H,,, and every paraffin hydrocar-
PARAFFINS,
bon up to C,,H,,, as well as some others, and derivatives of much
higher members of the paraffin series of hydrocarbons, are known,
General Character of the Paragfins.—The lower members of the
paraffin series are gases at ordinary temperatures; the next fol-
lowing members, beginning with butane and isobutane, are
liquids with very low boiling points, but with the boiling points
rising gradually, though not quite regularly, as the number of
carbon atoms in the molecule increases. When members with
fifteen or more carbon atoms in their molecules are reached, these
are colorless solids at ordinary temperatures, and boil at tempera-
tures mostly above 200°C, The paraffin wax largely used in the
manufacture of candles consists of a number of the higher paraffins
in a condition of mere mixture.
The specific gravities of the liquid and solid paraffins rise grad-
ually with the increase of molecular weight. All the paratlins
are considerably lighter bulk for bulk than water. They are all
very nearly insoluble in water but they are more or less soluble in
alcohol and ether.
As regards theirchemical characters, the paraffins are remark-
able for the resistance which they offer to the action of the
majority of the most active oxidizing and other agents, such as the
strong acids and alkalies generally, sodium, ete. When oxidation
of a paraffin takes place at all, it is frequently complete, carbonic
anhydride and water being the only products formed. The par-
affins are, however, easily attacked by chlorine in presence of
light ; less easily by bromine, These agents act by displacing one
or more hydrogen atoms, and substituting chlorine or bromine for
the hydrogen so displaced, hydrochloric or hydrobromic acid being
formed at the same time ;
C,H,.,, + Cl, = C.H,,,,Cl 4+ HCl
O.H,,,, + Br, = C,H,,,,Br + HBr
Petroleum Benzin. Paraffin Oil. Paraffin.
Petroleum Benzin, (Benzinum, U.S, P.), known also as benzolin,
petroleum spirit and petroleum ether is a colorless, very volatile, and
highly inflammable liquid obtained by distillation from the thin
-adeegen erude petroleum, and consisting of a mixture of the
ower members of the methane series of hydrocarbons ( pentane,
C.H,,, herane, C,H,,, etc.). Boiling point, 113° to 140° F. (46°
to 60°C.). Sp. gr. 0.638 to 0.660 at 77°F. (25°C.). (Benzene
or benzol is quite a different liquid.)
Purified Petroleum Benzin, (Benzinum Purificatum, U, 8. P.)
is prepared by treating Petroleum Benzin first with sulphuric acid
and potassium permanganate and then with sodium hydroxide
and potassium permanganate and washing the product with
water.
388 ORGANIC CHEMISTRY.
Paraffin Oil, Liquid Petrohataon, (Petrslahaiatiaeliates Ae aaa
a mixture of the higher liquid members of the
of hydrocarbons, is a clear oily liquid obtained from cm petroleum
off the lower boiling portions and
liquid residue. Sp. gr-, 0.870 to 0.940.
twice its volume of sulphuric acid, the oil is not
acid only tinged brown ; when heated with metallic
metal is not tarnished ; alcohol boiled with the oil
. officially
F
gf ;
Eeeke
it
ath
merce by various fanciful names (vaseline, etc.
mixture of paraffins, usually obtained by purifying &
tile portions of petroleum. It is yellow or light
translucent, soft, unctuous to the touch, free from
linity, odor, or taste. Specific gravity 0.820 to 0. pry 140°F.
(60° C.). Melts at 113° to 118.4° F. (45° to 48° C. ) volatilizes
without giving off acrid vapors, and burns witha bright
leaving no residue. Insoluble in water, scarcely soluble in cold
absolute alcohol, freely soluble in ether, chloroform, and benzol.
It is not saponified by solutions of alkalies, White Petrolatum
(Petrolatum Album, U. 8. P.), is a white unctuous mass, a mixture
of hydrocarbons, chiefly of the methane series, obtained
tilling off the more volatile portions from petroleum and
theresidue. Paragin (Paragiinum, U. 8. P.), remare
pérafin wax, is a mixture of several solid h
methane series; usually obtained by distillation from shale,
ation of the liquid oils by refrigeration, and at ee sear
solid product. It is colorless, semi-transparent,
inodorous and tasteless ; slightly greasy to the touch. Sp Be
(0.890 to 0.905. Insoluble in water, slightly soluble in
alcohol, readily soluble in ether. An alcohol solution should not
redden litmus. It melts at 125° to 135°F. (51.6° to 57.2° ©),
and burns with a bright flame, leaving no residue.
Paraffin resists all ordinary reagents (hence the original name
paraffin from parum affinis, ‘without affinity), but may, by con-
tinued boiling with sulphuric acid and solution of potassium
dichromate, be oxidized to cerotie acid, C.H,O, By continued
digestion with nitric and sulphuric acids it yields ‘acids of the
acetic series and paraffinic acid, C,,H,.O, (Pouchet).
inh
ae
QUESTIONS AND EXERCISES,
Draw graphic formule for methane, ethane, propane, butane, and
isobutane.—How many hydrocarbons of the formula GH are theare
ically possible and how many are known ?—What is meant by
Give several illustrations—Give examples of polymeric substances—
OLEFINES.
What is meant by the term “ homologous series "?—What is the general
formula for the hydrocarbons of the parattin series ?—Mention some of
the sources of paraffins.—Describe three general methods for the prepara-
tion of paraftins.—How would you prepare methane and ethane ?—What
are the substances known as petroleum spirit, paraffin oil, soft paraffin,
and hard paraffin ?—What is the derivation of the word paraftin ’
THE OLEFINE SERIES OF HYDROCARBONS.
In so far as composition is concerned, any member of the olefine
series differs from the paraffin which contains the same number of
carbon atoms in its molecule, by containing two atoms of hydro-
ven fewer. The general formula for the members of the olefine
series is accordingly C,H,,. This formula indicates that for each
atom of carbon in the molecule of an olefine there are two atoms
of hydrogen, and hence that the composition percent, of all the
olefines is the same, no matter how different their molecular
weights may be. Olefines may, therefore, be looked upon as paraf-
fins from which two atoms of hydrogen have been removed, and
such evidence as is available tends to show that this is a sutisfac-
tory view of their constitution, Moreover, it would seem that
the two hydrogen atoms are not to be regarded as having been
removed from the same carbon atom, but from two different atoms,
and that these two carbon atoms are always immediately neigh-
boring ones in the carbon nucleus. If this latter view is well
founded, it offers some explanation for the fact that an olefine
with only a single carbon atom in its molecule has never been
obtained and does not appear to be capable of existence. The
formula for such an olefine would be CH, but the lowest known
member of the olefine series, i, e., ethylene, is represented by the
formula C,H,.
The paraffins have already been described as saturated com-
pounds (p. 376), It is obvious from what has been stated in the
foregoing that the olefines cannot be regarded as saturated com-
vunds in the sense there indicated. Thus if we derive the
mmula for ethylene, C,H, from that for ethane, C,H,, we
should have .
H H HH
|
ia |
(eq) H—C—C—H and(6) H—C—C—H
| |
HH
representing ethane and ethylene respectively. But in the form-
ula (6) the combining capneity of each of the carbon atoms is
represented aa only three-fourths satisfied by linkage with other
atoms whereas in the forniula (@) it is represented as fully satis
fied, The olefines are thus ‘‘ unsaturated”? compounds, It is
390 ORGANIC CHEMISTRY.
customary in writing the formule for olefines, when these formule
are extended so as to represent each carbon atom separately, to
indicate the pair of carbon atoms whose combining capacity is
supposed to be only three-fourths satisfied, by drawing two strokes,
or, occasionally, by placing two dots between them. Thus the
formule for ethylene is written
: 3 ee: re
HoC=C< 4 or yp >C: Coy
which may be contracted into H,C=CH, or H,C:CH,; and in
the sume way the formula for propylene, C,H,, may be written
HH
y ( hoot or CH,. CH : CH,.
H
Although certain pairs of carbon atoms are represented by these
formule as doubly linked, the assumption that these pairs of car-
bon atoms are more firmly linked to each other than in the cases
where only single linkage is represented, seems not only to be
unsupported but rather to be controverted by the chemical behay-
ior of the substance.
Tsomerism in the Olefine Series,—Just as there are possible vari-
ations in the arrangement of the atoms present in those paraffins
which contain four or more carbon atoms in their molecules, so in
the olefines corresponding to these paraffins such variations are
also possible. If the formule for ethane, propane, normal butane,
and isobutane are considered with regard to the olefines deriv-
able from them, it will be seen that in the cases of ethane, of
propane, and of isobutane, the removal of one atom of hydrogen
each from any two immediately neighboring carbon atoms, leads
to the formula of only one olefine from each paraffin, but that in
the case of normal butane two different formule may be arrived
at, depending upon which hydrogen atoms are supposed to be
removed, thus:
CH, CH,
CH, CH, . |
gives || ; CH, gives CH ; and
CH, CH, |
CH,
CH,
H—C—CH, gives C—CH,
T
OH,
|
CH
P|
OLEFINES. ag
There are thus three possible variations of the olefine formula
C,H, derivable in the manner described from the two variations
(p. 377) of the paraffin formula C,H,,. In agreement with this it
is of interest to note that three oletines (and only three) have been
obtained all with molecular weight corresponding to the formula
C,H,. These three are commonly represented by the formule
given above. It is here unnecessary to further discuss these
olefines, or indeed any members of the series except ethylene
(p. 392).
The view of the constitution of olefines in accordance with which
they are regarded as paraffins from which two atoms of hydrogen
have been removed (p. 389) gains support from some of the methods
of general applicability by which olefines are ordinarily prepared.
Of these methods, one may be discussed here with some detail,
namely, that by the action of boiling alcoholic solution of potas-
sium hydroxide upon the mono-halogen derivatives of the paraflins
(C,H,,.,X, where X stands for Cl, Br, or 1). In this interaction
the potassium atom of the potassium hydroxide unites with the
halogen atom of the organic halide ' forming potassium halide (just
a8 in the interactions of potassium hydroxide with many metallic
halides) but the hydroxy! group (OH) of the potassium hydroxide
does not take the place of the halogen atom (as is usual when
potassium hydroxide interacts with metallic halides), Instead of
this the hydroxyl group unites with a hydrogen atom of the organic
halide (supposed to be a hydrogen atom linked to a carbon atom
immediately adjoining the one to which the halogen atom was
linked) to form water, and an olefine is produced, thus;
C,H,,,,.X% 4 KOH = KX + H,O + C\H,,
That is to say, boiling alcoholic solution of potassium hydroxide
removes hydrogen and halogen from the organic halide in the pro-
portions in which these unite to form hydrogen halide ; and the
products of the action are, besides the olefine, the same substances
as would be produced by the interaction of potassium hydroxide
and hydrogen halide (7. ¢., potassium halide and water),
It is of interest to note here that the mono-halogen derivatives
of methane are exceptional in respect to their behavior toward
alcoholic solution of potassium hydroxide, since potassiom halide
and methy! alcohol are produced, by the interaction, and no olefine ;
CH,X + KOH = KX + CH,OH
This exceptional behavior is of importance as evidence in favor of
the view that two different carbon atoms are concerned ip the con-
' Halide is a general name sometimes employed to designate a halogen
compound when it is immaterial which halogen the compound contains,
(Compare p, 256),
392 ORGANIC CHEMISTRY.
dition of non-saturation of an olefine as compared with a
(p. 889). ‘It is obvious that a molecule of methyl! iodide, CH,I,
cannot lose an atom of iodine from one carbon utom and an atom
of hydrogen from another,
In virtue of their character as ‘‘ unsaturated ’’ compounds the
olefines combine with two halogen atoms, or with a molecule of a
hydrogen halide to form saturated compounds of the gen
formule C,H,,X, and C,H,,,,% respectively,
Occurrence of Olefinea in Nature,—Certain olefines occur, mixed
with paraffins, in some of the natural gases and crude petroleums
which issue from the earth in various parts of the world.
Production of Olefines in the Dry Distillation of Coal, ete,—Ole-
fines are always present, and are valuable in illuminating constit-
vents, in coal gas (p. 297). The ordinary coal gas supply of
towns contains from 3 to 12 percent. by volume of olefines—chiefly
ethylene.
A large number of olefines have been prepared. Zithylene, CH, ;
Propylene, C,H; Butylene, CH,; Amylene, C,H, ; Hexylene, CH, ;
and Heptylene, C,H,, are examples; and many others are well-
known,
Ethylene, Olejiant Gas, Heavy Carburetted Hydrogen, CH,.—
This olefine can be obtained by the action of boiling alcoholic solu-
tion of potassium hydroxide upon ethyl iodide (p. 808) :—
C,H,I + KOH = KI + H,0 + 6,4,
It is usually prepared, however, from common (ethyl) aleohol,
O,H,OH, by the action upon it, at a high temperature, of concen-
trated sulphuric acid.
Preparation.—Ethylene may be prepared by dropping
alcohol into a large retort or flask containing 10 ounces of
sulphuric acid and 3 ounces of water, previously mixed, and
heated to 160—165° C. The liberation of the ethylene ander
these conditions is supposed to he preceded by the formation
of ethyl hydrogen sulphate (sulphovine acid), C,H,HS80,;
which undergoes decomposition yielding as chief products ethy-
lene and sulphuric acid. The gas is washed by passing it
first through cold water and then through a solution of sodium
ewe to free it from ether, alcohol, and sulphurous anhy-
dride.
C,HOH + HSO, = C,H,HSO, + HO
Ww
ae : ‘ae
Aleohol Sulphuric Ethyl hydrogen aler
acid sulphate
C,H,HSO, = C,H, + 4H,80,
OLEFINES. 393
Ethylene is a colorless gas which possesses a peculiar, although
not unpleasant smell, It is almost insoluble in water and is only
slightly soluble in aleohol. It cam be condensed to the liquid state
at ordinary temperatures by the application of a pressure of about
60 temperatures. It burns in air with a highly luminous flame,
C,H, + 80,= 2CO, + 2H,O. Ethylene combines directly with
chlorine, with bromine, and with iodine, forming ethylene chloride,
C,H,Cl,, ethylene bromide, C,H,Br, , and ethylene iodide, C,H,1,,
respectively. The two former are ‘liquids (pp. 398, 394) the latter is
a crystalline solid. Ethylene further unites with hydrogen brom-
ide and with hydrogen iodide, forming ethyl bromide, C,H,Br,
and ethyl iodide, C,H,I respectively.
If the hacer formula for ethylene be assumed to be
- 1 (p. 390), the formule for ethylene chloride,
H—C=C—H
bromide, and iodide may be written as follows ;—
H H H H
ae
H _} = H—C—C—H
el fl
Cl Cl Br Br
Additional Chemical Characters of Olefines.—Besides the chemi-
cal characters of olefines already described, two others depending
upon their nature as unsaturated compounds may be mentioned.
1, Olefines can be converted into paraffins by direct union with
hydrogen, ‘This is effected by passing a mixture of the olefine
and hydrogen through a tube packed with platinum black.
C,H, + H, = C,H,,,,
2, Olefines are absorbed by concentrated sulphuric acid (better
by sulphuric acid in which sulphuric anhydride is dissolved) with
the formation of en like ethy! hydrogen sulphate (p. 392).
_ 0H
C,H 1180,
oat ~,
These compounds are of interest and importance in organic
synthesia, for on heating them with water an alcohol is produced
and sulphuric acid is reformed :
O.F,.,;- H
H
80, + H,O = C,H,,,,0H +- qo,
Ethylene Chloride, C,C1,.—When equal volumes of ethylene
and chlorine are mixed over wator and exposed to daylight, they
394 ORGANIC CHEMISTRY.
unite very readily, with the formation of oily drops which trickle
down the sides of the containing vessel and colleet below the
water :
C,H, + Cl, = ©,H,Cl,
Ethylene chloride is a colorless liquid, its odor resembling that of
chloroform. It boils at 85° ©,
Ethylene Bromide, C,H,Br,.—Is prepared by bubbling ethylene
into bromine (by which it is rapidly absorbed) until the color of
the bromine entirely disappears. A good deal of heat is given out
during the combination, and the bromine must be kept cold :
C,H, + Br, = C,H,Br,
Ethylene bromide is a colorless liquid possessing a pleasant
ethereal smell. It boils at 138° C,
THE ACETYLENE SERIES OF HYDROCARBONS.
Each member of this series of hydrocarbons differs from the
parafiin with the same number of carbon atoms in its molecule, by
containing four atoms of hydrogen fewer. The general formula
for the acetylene series is therefore C\H,,_..
The first member of this series is acetylene, C,H, Other
members are Allylene, C,H, ; Crotonylene, C\H, ; ete. Acetylene
is the only one which will be treated of here. The following dis-
cussion of one of the modes of formation of acetylene should give
a sufficient view of the way in which this hydrocarbon is supposed
to be constituted, The change which takes place when the mono-
halogen derivatives of the paraffins (C,H,,, ,%) are acted upon by
a boiling alcoholic solution of potassium hydroxide has already
been stated on p.391 as resulting in the removal, from each mole-
cule, of the halogen atom and a hydrogen atom. When a di-
halogen derivative of a paraffin (C,H,,X,) is subjected to the same
action an exactly analogous change usually takes place, but im
such a case each molecule often loses both halogen atoms and (ico
hydrogen atoms. Thus when ethylene bromide, C,H,Br, (see
above) is employed, acetylene is produced :
C.H,Br, + 2KOH = 2KBr + 2H,0 + C,H,
The action in this case can be separated in actual experiment into
two stages : in the first, one halogen atom and one hydrogen atom
are removed; in the second the remaining halogen atom and
another hydrogen atom are removed.
ACETYLENE. 395
Acetylene, C,H,.—This hydrocarbon is produced by direct union
of the elements when electric sparks are passed between carbon
terminals in an atmosphere of hydrogen. This method of produc-
tion is of great interest as a mode of obtaining an organic com-
pound from purely inorganic materials, Acetylene is also pro-
duced in small quantity in many cases of incomplete combustion
of substances containing carbon and hydrogen, One of the best
known instances of this is its formation in a Bunsen burner when
the gas is kindled at the gas inlet jet (close beside the air inlet
holes at the base of the upright metal tube). Formerly when
acetylene was required in quantity it was obtained either from this
source by separating it from the other products of the combustion,
or else by the action of boiling alcoholic solution of potassium
hydroxide on ethylene bromide as already discussed in the preced-
ing paragraph. It is now prepared as a commercial product on
the large scale for illuminating purposes, by the action of water
upon calcium carbide, Cat, :
CaC, + 2H,0 = Ca(OH), + C,H,
The solid carbide is simply treated with cold water, when a brisk
effervescence of acetylene at once takes place,
Acetylene is a colorless gas possessing a disagreeable odor. It
burns in air with an intensely luminous flame :
20,H, + 50, = 4C0, + 2H,0
A mixture of acetylene and oxygen in the proportions repre-
sented by the above equation, explodes with extreme violence on
the application of a light,
A striking property of acetylene (and one characteristic of hydro-
earbons in which the group—C : C—H is assumed to exist) i8
that of combining to form compounds containing copper or silver,
and commonly called ‘‘acetylides.’"’ Thus when acetylene ‘is
bubbled into an ammoniacal solution of cuprous chloride a red-
dish-brown precipitate is produced of copper acetylide, the com-
position of which is generally supposed to be represented by the
formula C.H,Cu,O, This copper compound is usually preserved
in a moist condition, because when dry it is liable to explosive
decomposition by friction or by gentle heating. It may be decom-
posed by the action of concentrated hydrochlorie acid, or better
of potassium cyunide solution, when acetylene is libernted,
In accordance with its character as an unsaturated compound,
acetylene combines direetly with hydrogen to form ethylene, which
in turn combines with hydrogen to form ethane (compare p,. 892
Acetylene also combines directly with the halogens and with
hydrogen halides, fully saturated compounds, such as C,H,Br,,
, being obtained as final products,
oa highly important character of acetylene is its convertibility
396 ORGANIC CHEMISTRY.
into benzene, The conversion is aoa effected by exposing it for
some time toa high temperature, 8C,H,=C,H,. This change
is a good example of polymerisation, and further, it furnishes an
example of the formation of an ‘‘aromatic’’ compound from a
‘* fatty ’’ one.
Other Series of Hydrocarbons.—There are other series of fatty
hydrocarbons whose members contain hydrogen in still smaller
proportion relatively to the carbon than is the case with the mem-
bers of the paraffin, the olefine, and the acetylene series ; but these
cannot be treated of here,
QUESTIONS AND EXERCISES,
What is the general formula for the hydrocarbons of the olefine series?
—How many olefines of the formula CyHs are known
prepared and what are its properties ?—How may ethylene chloride and
bromide be prepared ?—Whiat is the general formula for the hydrocarbons
ofthe acetylene series?—How is acetylene prepared and what are its
chief properties ?—How may benzene be prepared from acetylene?
Halogen Derivatives of the Paraffins.
The members of the paraffin series of hydrocarbons have already
been discussed as saturated compounds, and as such they do not
unite with the halogens to form halogen-addition products, 7 ¢.,
products containing all the atoms of the original paraffins, and
halogen atoms besides. But compounds can be obtained which
may be looked upon as paraffins in whose molecules the place of
a part or of the whole of the hydrogen is taken by halogen, Such
compounds, of which several have been mentioned already, are
commonly called halogen derivatives of the paraffins, It 1s only
necessary to mention here some of the commoner methods for the
preparation of these derivatives, and to discuss some of the sub-
stances themselves which are of the greatest theoretical interest or
erg importance.
The hydrogen of the paraffins (or in some cases a part of it
at Sea can be displaced and chlorine “ substituted"’ for it by
treating the paraffins with chlorine in daylight, This is called
‘chlorination’ or “c hlorine-substitution.’’ Bromine, under the
aime conditions, behaves similarly but somewhat Jess readily
unless the action is assisted by heating. Todine, on the other
hand, scarcely acts in this way atall. In the case of methane
the hydrogen is removed and chlorine substituted for it In stages,
HALOGEN DERIVATIVES OF HYDROCARBONS. 397
with the formation of four different products, as represented by
the four following equations ;
CH, + Cl, = HCl + CH,C! CH,Cl, + Cl, = HCl + CHCl,
CH,Cl + Cl, = HCl+CH,cl, | CHCl, + Cl = HCI + CCl,
The products (other than the hydrochloric acid) of these four
reactions are named as under :
CH,CL Mono-chloro-methane; or methyl chloride,
CH,Cl, Di-chloro-methane; or methylene chloride.
CHCl, = Tri-chloro-methane; or methenyl or formyl! chloride; or
chloroform.
CCl, Tetra-chloro or perchloro-methane or carbon tetra-
chloride,
Starting from methane, however, more than one of the above
four reactions take place to some extent side by side no matter how
small the proportion is in which the chlorine is employed ; so that
this is not a suitable method for obtaining pure intermediate
products.
2. Halogen derivatives of the paraffins are produced when
hydrocarbons of the ethylene and acetylene series combine with
halogens or With hydrogen halides to form saturated compounds,
Thus ethylene and acetylene combine with bromine and with
hydrobromic acid to form saturated compounds.
8. Mono-halogen derivatives of the paraflins are prepared by
the action of the hydrogen halides, or better, of the phosphorus
halides upon alcohols of the general formula C,H,,, OH ; water,
or an oxygenated compound of phosphorus (phosphorous or phos-
phorie acid, or a phosphorus oxyhalide) being formed at the same
time:
C,H,,,,0H + HX = H,O + C,H,,,,%
30, H,,4,0H + PA, = H,PO, + 8C, Hy. X
When the hydrogen halides are employed the reactions never
become complete, but a balance is eventually established owing to
the tendency of the water formed to interact with the halogen
derivative, and produce alcohol and acid again. When the phos-
phorus halides are employed other reactions besides that repre-.
sented by the above equation take place to a considerable extent,
Methyl and ethyl iodides are usually prepared by the action
of phosphorus tri-iodide upom methyl and ethyl alcohols
respectively :
8CH,OH + PI, = HPO, + 8CH,1
3C HOH + PIL=H,PO,+ 8C,H,1
It is not necessary that the phosphorus tri-iodide should be pre-
pared beforehand and then added to the alcohol. It is sufficient
ou8 ORGANIC CHEMISTRY,
to mix the alcohol with phosphorus and then to add the iodine
slowly. Red phosphorus is generally employed. The course of
the reaction may fairly be assumed to consist in the formation, in
the first place, of phosphorus tri-iodide, which then interacts with
the aleohol as represented above. The methyl or ethy] iodide is
distilled away from the phosphorous acid and other products of
the reaction, and is further purified by drying over calcium echlo-
ride and subsequent redistillation.
Methyl Chloride, CH,Cl, and Methyl Bromide, CH,Br, are
vases at ordinary tem peratures, but both can easily be condensed
to the liquid state. The former is prepared from one of the by-
products of the beet-sugar manufacture, and has found several
industrial applications.
Ethyl Chloride, Aethylis Chloridum, U. 8. P., CJH,Cl, and Ethyl
Bromide, C,H Br, are liquids with low boiling points, and both
have been employed as anesthetics in dentistry. Ethyl chloride
is produced by the interaction of dry hydrochloric acid gas with
absolute alcohol :
C,H,OH + HCI=C,H,Cl + H,0.
Ethy] bromide may be prepared by gradually adding 6 parts of
bromine to a mixture of 6 parts of ethyl alcohol and 1 of amor-
phous phosphorus contained in a flask fitted with an upright con-
denser, care being taken to keep the apparatus cool:
8C,H,OH + PBr, = 3C,H,Br b. H,PO,
When all the bromine has been added, the mixture is poured
into w retort and distilled over a water-bath, the resulting ethyl
bromide freed from excess of bromine by washing with a small
quantity of dilute sodium or potassium hydroxide, then washed
with water, dried over calcium chloride, and redistilled.
For the preparation of ethyl bromide on a large scale, De Vrij’s
method is preferable, C,H,HSO,+KBr=C,H,Br+KHSO, (see
Pharm. Journ., 15th Feb., 1879), or the same method as modified
by Greene (P. J., 12th July, 1879), Re mington (P. J., 29th May,
L880), or by tole Ck J. 8rd July, 1880).
Methyl and Ethyl Jodides, CHT and C,H, ,I, are generally pre-
pared by the method already described, (method 3 ante). They
are both colorless liquids of peculiar but not unpleasant smell.
Methyl iodide boils at 45° C.; ethyl iodide at 72.8°C. Both
iodides are very largely employed, and are of great importance,
in the synthetic formation of other organic compounds, Instances
of their employ ment have alre ady been given on pp. 882, 383,
ete, They should be kept in the dark, as exposure to light pro-
motes decomposition with separation of iodine.
CHLOROFORM.
Chloroform.
Chloroform or Trichloromethane (Chioroformum,U. 5. P.), CHCl,,
This very important substance is prepared in large quantity for
use in an anesthetic, as a solvent, and for other purposes, It is
prepared on the commercial scale, j in metal stills, by the action of
bleaching-powder, at a temperature of about 45° ©, . on ordinary
aleohol which has been diluted with about 16 to 20 times its
weight in water. When the reaction has set in no further heat-
ing is necessary, as sufficient heat is given out during its pro-
gress. A mixture of substances distils off, and, on being condensed
to the liquid state the distillate separates into two layers. The
lower layer, which consists of crude chloroform, is separated from
the upper aqueous layer, and is purified by shaking it with water
and then with pure sulphuric acid, (containing no trace of nitric
acid), which chars and removes hydrocarbons, etc., but does not
uffect chloroform. It is freed from any trace of acid by agitation
with lime, and from moisture by solid calcium chloride. It is
finally rectified. Instead of alcohol, commercial acetone is now
largely employed as a substitute in the preparation of chloroform,
the product being known in trade as ‘' ketone chloroform.’’ The
exact nature of the changes which take place in the preparation
of chloroform from alcohol or acetone is not only complicated but
also somewhat obscure.
Experiment.— Place 14 fluid ounce of aleohol (90 percent. )
and 24 ounces of water in a retort or flask of at least a quart
capacity ; add 8 ounces of chlorinated lime and 4 of slaked
lime; connect the vessel with a condenser, and heat the mix-
ture until distillation commences, the source of heat then being
withdrawn. The condensed liquid should fall into a small
flask containing water, at the bottom of which about a drachm
of chloroform will slowly colleet.
Chloroform ts produced when chloral is warmed with aqueous
solution of potassium or of sodium hydroxide, and for the sake of
greater purity it is sometimes prepared from chloral in this way.
It is stated that chloroform is also manufactured by the action of
chlorine upon methyl chloride (compare p. 396),
Properties, —The sp. gr. of pure chloroform is at least 1.494 at
77° F, (25° C.), It is liable to slowly decompose when exposed to
air and light; 4CHCI, + 380,= 4COCI, 4+- 2H,0 + 2C),, The
resulting chlorine may be detected by ‘adding zinc iodide and
starch, and the carbon oxychloride (carbonyl chloride, phosgen,
p. 200) by means of baryta water : COC, +- 2Ba(OH), = BaCO,+
Batl, 4 2H, ©. To render chloroform stable, 1 minute amount
(1 volume { in 100 or leas) of absolute alcohol is necessary ; hence
the specific gravity of medicinal chloroform is about 1,476,
400 ORGANIC CHEMISTRY,
Chloroform is not decomposed by the action of sunlight unless
oxygen is present, when, in the first stages of the decomposition,
chlorine is liberated, and this, acting on the alcohol contained in
the chloroform, produces hydrogen chloride, which is then found
instead of free chlorine. Hence the liberation of chlorine has
been disputed by some who have overlooked the presence of alco-
hol in the chloroform operated on, Chloroform readily and
entirely volutilizes at ordinary temperatures, having, to the last
drop, its pleasant characteristic odor, It has a sweetish taste, is
limpid, colorless, miscible in all proportions with alcohol and
ether, and slightly soluble in water. It may be so frozen at low
temperatures that any impurities shall remain in the still fluid
portion (Pictet). It boils between 140° and 141.8° F. (60° and
61°C.), It burns with a sluggish, green, smoky flame, It reduces
Fehling’s solution. It should-be neutral to test-paper, indicating
absence of acid; give no precipitate with solution of silver nitrate,
indicating absence of ordinary chlorides; remain colorless when
heated with potassium hydroxide, indicating absence of aldehyde;
and when shaken with concentrated sulphuric acid should give no
more color than is producible by the absolute alcohol that is pres-
ent, even after the mixture has been set aside for half an hour,
indicating absence of hydrocarbons, etc. Alcohol may be
detected by the iodoform test, or by shaking with a little of the
dye termed ‘‘Hofmann's violet,’’ which gives the chloroform a
purple tint if alcohol be present, but affords no color with pure
chloroform, At the temperature of melting ice, chloroform unites
with water to formacrystalline compound, CHCI,, 18H,0,
Chloroform is an important solvent ; it dissolves sulphur, phos-
phorus, and iodine, as well as fats, resins, India-rubber, alkaloids,
many alkaloidal salts, and numerous other organic compounds.
Chromic anhydride acts on chloroform, converting it into
phosgen, COCI,. 2
Aqua Chloreformi, U. 8. P., the official Chloroform Water, is
made by repeated agitation of chloroform with distilled water till
the water is saturated, and is preserved in presence of a slight
excess of chloroform,
Bromoform.
Bromoform or Tri-bromomethane, (Bromoformum, U. 8S. P.), is
easily prepared by the gradual addition of bromine to a mixture
of ethyl alcohol and an aqueous solution of potassium hydroxide,
and subsequent purification of the heavy liquid which separates.
[t is a colorless liquid of sp. gr. 2,808 which boils at 298,4°F.
(148°C,),
SPIRIT OF NITROUS ETHER. 401
Iodoform,
Iodoform or Tri-iodomethane (Jodoformum, U. 8, P.),
CHL,, is analogous in constitution to chloroform, the iodine
occupying the place of the chlorine. It ismade by mixing
together one part of alcohol, two parts of crystallized sodium
carbonate, and ten parts of water; the whole being heated
to about 150° F. (65.6° C.), and one part of iodine gradually
added in small portions. When the liquid becomes colorless,
the iodoform is allowed to settle. It is then collected ona
paper filter, washed thoroughly with water, and dried between
filter paper. (This reaction forms a very delicate means of
testing for the presence of alcohol. )
Todoform is now prepared on the manufacturing scale by the
electrolysis of a solution in aqueous alcohol of potassium iodide
and potassium carbonate, carbonic anhydride being passed into
the solution from time to time to convert into carbonate the potas-
sium hydroxide formed during the electrolysis. Chloroform and
bromoform may be obtained in an analogous manner, potassium
chloride or bromide being substituted for the potassium iodide,
Iodoform occurs as yellow, shining, six-sided scales, It is vola-
tile at ordinary temperatures; almost insoluble in water, soluble in
alcohol or ether. Warmed with an alcoholic solution of potassium
hydroxide, potassium formate and iodide are produced, CHI, +
4KOH = HCOOK + 3KI + 2H.O; and the resulting fluid,
heated with a little nitric acid, yields free iodine, recognizable by
its color or giving a blue reaction with starch.
Esters.
The paraffins give rise to many substitution derivatives by dis-
placement of their hydrogen by compound acid radicals. These
derivatives are now commonly designated by the German word
‘‘eater."’* The following, chiefly derived from ethane and pen-
tane, are of pharmaceutical interest :—
Spirit of Nitrous Ether,
Ethyl Nitrite, Nitrous Ether, CA,NO,—A “spirit, "’ probably
containing nitrous ether, was one of the earliest known medicinal
"The name esters is now Used instead of *‘ compound ether" or “ ether
eal salt” terms which were formerly in general use. The use of the word
ether in strictly systematic chemical nomenclature, is now confined to a
diferent group of organic compounds (see p. 447), but in popular language,
and in pharmacy, the word is not always confined to this group.
26
ORGANIC CHEMISTRY,
compounds, its discovery being generally ascribed to Raymond
Lully.
Experiment.—To a third of a test-tubeful of alcohol add
about a tenth of its bulk of sulphuric acid, rather more of nitrie
acid, and some copper wire or turnings, and warm the mix-
ture; as soon as ebullition commences, the yapor of nitrous
ether (with other substances) is evolved, recognizable by its
odor. A long bent tube, kept very cool to serve as a con-
denser, may be adapted by means of a perforated cork to the
test-tube, and thus a little of the product may be condensed
and collected.
Disregarding the other products formed besides ethy! nitrite and
aldehyde, the following equation probably represents the chief
decompositions that occur in the interaction. An important feat-
ure in the reaction is the reduction of the nitric to the nitrous
radical :—
80,H.OH + 2HNO, + H,S0O, + Cu
Alcohol Nitrle Sulphuric Copper
acid aci
= 20, HNO, + OHO + 4H,0 + CuSO,
hitrous Aldehyde Water Cupric
ether sulphate
The official process for the preparation of spirit of nitrous ether
(Spiritus theris Nitroei, U.S.P.), consists in allowing a solution
of sodium nitrite to drop slowly into a mixture (which is kept cool)
of alcohol and sulphuric acid, separating the lighter layer of liquid,
purifying it by washing with water and then with sodium carbon-
ate solution, treating it with solid potassium carbonate to remove
water, and pouring the product into a further quantity of alcohol.
2NaNO, + H,SO, + 2C,H,OH = 2C,H,NO, + NaSO, + 2H.0
Sedium Sulphuric Alcohol Ethyl Sodium Water
nitrate acid nitrite sulphate
Properties.—Spirit of Nitrous Ether is a clear, mobile liquid
having a very faint yellowish tinge, inflammable, of a peculiar
penetrating, apple-like odor, and a characteristic taste. Sp. gr.,
about 0.823. It should not effervesce when potassium bicarbonate
is added to it (showing absence of appreciable quantities of free
nitrous, acetic or other acids). The aldehdyde in it may be detected
by the potassium hydroxide test (see ‘‘ Aldehyde, Test for’? in
Index). The great tendency of aldehyde to become converted
into acetic acid by the absorption of oxygen from the air renders
Spirit of Nitrous Ether unstable, and pharmacists are obliged to
neutralize such acid, generally by means of potassium bicarbonate,
before adding it to medicines containing iodides, ete, The nitrous
NITRO-COMPOUNDS. 403
radical may be detected by adding a concentrated solution of ferrous
sulphate mixed with sulphuric acid to some of the spirit of nitrous
ether, the usual dark compound being produced.
Spirit of nitrous ether assayed by the official process should yield
results indicating not less than 4 percent. of ethy! nitrite.
The reaction which takes place in the official ussay is as
follows :—
20,H,NO, + 2KI + 2H,SO, = 2C,H OH + 2KHSO,+-I,4+2NO
A very old variety of spirit of nitrous ether, or rather of *‘ sweet
spirit of nitre’’ (Spiritus Nitri Dulcis, P. L., 1746), still sold in
Great Britain, is made from rectified spirit and nitric acid as
ordered in the London Pharmacopeeias, except that the distillution
is continued until the product has a sp, gr. of 0,850, It may
contain little or no ethyl nitrite, but is popular as a stimulant.
Nitro-Compounds.—There are two derivatives of ethane which
possess the composition represented by the formula, C,H,NO, but
which differ very much in properties, namely, ethyl nitrite, which
boils at 63.5° F, (17.5° C.) and has asp. gr. of 0.900 (at 0° C. ;
water=1; 0.917 to 0.920 ; Dunstan and Dymond) and nitro-ethane
which boils at 235° F. (nearly 113° C.). The official spirit of
nitrous ether contains ethy] nitrite. There are also two analogous
derivatives of methane (CH,NO,), namely, methyl nitrite and nitro-
methane, The nitrites are easily decomposed, and nitro-compounds
are stable. Moreover, the reactions of the two sets of compounds
warrant the conclusion that in the nitrites the methy! or ethy! group
is united to oxygen, in the nitro-compounds to the nitrogen, The
nitrites are, the nitro-compounds are not, saponifiable; on reduc-
tion, the nitrogen of the former does not, while that of the latter
does, remain with the radicals, yielding amines. Possibly the
nitrites contain the nitrogen in the trivalent condition, while in
the nitro-compounds it is quinquivalent, as represented by the
following formule for the compounds just mentioned as well as for
the two corresponding derivatives of pentane, namely, amy! nitrite
and nitro-pentane :—
Methyl nitrite, CH—O—N=0, _Nitro-methane, CH,—N¢
Ethyl! nitrite, C,H,—O—N=O Nitro-ethane, C,H,—N¢ ¢
P23
Amy! nitrite, C.H,—O—N=0. = Nitro-pentane, C,H NE :
Ethyl Acetate or Acetic Ether.
Ethyl Acetate or Acetic Ether (ther Aceticus, U. & P.),
CH,CO,OCH,, or C,H,.C.H,.O,.—To a little dried sodiinn
acetate in a a test- tube, ‘add a small quantity of alcoho! and some
404 ORGANIC CHEMISTRY,
sulphuric acid. Adapting a long bent tube in the usual
manner, heat the test-tube and so distil over acetic ether—
which may be collected in another test-tube kept cool by
partial immersion in cold water.
On a larger scale the following proportions may be used ; aleo-
hol (90 percent.) 32} fluid parts ; sulphuric acid, $2) fluid age
sodium acetate, 40 parts; potassium carbonate, freshly dried,
parts, Slowly ‘add the acid to the alcohol, keeping the liquid it)
and the product being cold, add the acetate, mixing thoroughly.
Distil forty-five fluid parts. Digest the distillate with the potas-
sium carbonate for three days in a stoppered bottle. Separate the
ethereal fluid, and again distil until all but about four fluid parts
have passed over. Preserve the resulting acetic ether in a well-
closed bottle and in a cool place. It is a colorless liquid with an
agreeable ethereal odor. Sp. gr., 0.883 to 0.885, Boiling-point,
about 161.6° F. (72° C.). Soluble in all proportions in alcohol
and in ether. One part, by weight, dissolves in about 7 parts of
water at 77° F. (25° C.).
C,H,OH + CH,.CO.ONa + H,80,
A ‘le ohol Sodium Hydrogen
acetate sulphate
= CH,CO.OC,H, + NaHSO, + H,0
Ethyl! Sodium hy »dro- Water
acetate ven sulphate
Ethyl aceto-acetate, or aceto-acetic ether, is of great importance
in synthetic chemistry, as through its means a variety of substances
can be built up. In constitution it is the ethyl salt of aceto-acetic
acid, and its formula is CH,.CO,CH,.COOC,H,. It is prepared
by acting on ethy! acetate with sodium, treating the product with
a dilute acid, and subjecting the crude aceto-acetic ether to frac-
tional distillation,
Amyl Acetate, CH,.CO.OC,H,,, or C,H,,C,H,O,—To a
small quantity of amy! alcohol (fusel oil may be used ) in a
test-tube add some potassium acetate and a few drops of sul-
phuric acid, and warm the mixture ; the vapor of amyl acetate
is evolved, recognizable by its odor, which resembles that of
the jargonelle pear. If a condensing tube be attached, the
acetate may be distilled over, washed ‘by agitation with water,
to free it from alcohol, and separated hy means of a pipette.
CH,.CO.OK + C,H,OH + H,SO,
Potassium Amy) Sulphurle
acetate aleohol acid
= CH,.CO.0OC,H,, + KHSO, + H,O
Any! Anté potenticim Water
acetate phate
AMYL NITRITE. 405
Artificial Fruit-easences.—Amy]| acetate, prepared with the proper
proportions of materials, as indicated by the above equation, is
largely manufactured for use as a flavoring agent by confectioners.
Amy] valerate, C,H,,C,H,O,, is similarly used under the name of
apple-oil, Ethy! butyrate, C,H,C,H,0,, closely resembles the odor
and flavor of pine-apple ; ethy! cnanthylate, C,H,C,H,,0,, recalls
green-gage; ethyl pelargonate, C,H.C,H,.O,, quince ; ethyl! suber-
ate, (C,H,),C,H,,0,, mulberry; ethy! sebacate, (C,H,),C,H,,0,
melon, By mixing such esters with each other and with essen-
tial oils in various proportions, the odor and flavor of nearly every
fruit may be imitated.
Amyl Nitrite.
Amyl Nitrite, CH, NO, ( Amylis Nitris, U. 8. P.).—This may
be prepared by the direct action of nitric acid on amy! alcohol,
the nitric acid being reduced to nitrous by a portion of the alcohol,
valeric aldehyde and valeric acid also being produced. The tem-
perature must be very carefully regulated, or the reaction may
become extremely violent; indeed, even with small quantities a
violent explosion may occur. For experimental purposes it is
preferable to pass the nitrous gases generated by the action of
nitric acid on white arsenic or on starch, into the amy) alcohol
(kept cool by placing the vessel in cold water) until the alcohol is
saturated. The product is shaken with an aqueous solution of
potassium hydroxide or carbonate to remove free acids, and the
oily liquid is then separated and distilled. The portion distilling
between 205° and 210° F. (96° to 99° C.) is amyl nitrite.
The official amy] nitrite is a yellowish ethereal liquid ; sp. gr.,
0.865 to 0.875 ; boiling-point, 204. 8° to 210,2° F. (96° to 99° C,);
soluble in alcohol, insoluble in water; converted by fused potas-
sium hydroxide into potassium valerate; exposed to the air, it
yieldsamyl alcohol. It should contain 80 percent. ofamy! (chiefly
iso-amyl) nitrite,
Amyl nitrite may contain both alpha-amyl and beta-amy!
nitrites, iso-buty] nitrite, and propyl nitrite. These nitrites are,
of course, derived from the corresponding alcohols (see p, 425)
present in the crude amy! alcohol of commerce,
Nitropentane, C,H, NO,, is similar to amyl nitrite in composi-
tion, but differs much in properties, It is obtained by the inter-
action of amy! iodide and silver nitrite. It boils at 300° to 320° FP.
(148.8° to 160° C.),
QUESTIONS AND EXERCTSES,
Give details of the production of chloroform from alcohol.—Uive two
ways of preparing iodoform.—Give the formule and state the constitution
406 ORGANIC CHEMISTRY.
of the various chlorine derivatives of methane.—How is chloroform puri-
fied ?—State the characters of pure chloroform.—Explain the official pro-
cess for the preparation of nitrous ether,—Give the properties of nitrous
ether as compared with nitro-vthane,—By what official method is the
strength of spirit of nitrous ether to be estimated ?—How is ethy] iodide
made ?—Mention the systematic names of several artificial fruit-essences,
—What is the formula of amy! nitrite, and how is it prepared?
THE BENZENE SERIES OF HYDROCARBONS,
The Benzene or Aromatic Series, O,H,, ,.—This series is of great
general interest, Just as each consecutive member of the paraffin
series of hydrocarbons may be regarded as derived by the displace-
ment of a hydrogen atom of the preceding member by the methyl
(CH,) group, or of a hydrogen atom in methane by a paraffin
radical, so the consecutive members of the benzene series of hydro-
carbons may for convenience of study be viewed as obtained by
the displacement of one or more hydrogen atoms in benzene by
paraffin radicals ; as in the following examples :—
Benzene, C,H,.
Toluene or M ethylbenzene, C_H, or C,H,.CH,,.
Xylene or Dimethylbenzene, OH, or c,H,. (CH,),.
Mesitylene or Trimethylbenzene, C)H,, or C,H, (CH,) ;
Cymene or Methyl-isopropylbenzene, C,,H,, or O,H,.CH,. C,H,.
The members of the benzene series are unsaturated hydrocarbons,
A molecule of benzene itself readily unites with two, four, or six
atoms of chlorine, forming what are termed addition compounds,
as distinguished from the substitution compounds, in which the
hydrogen atoms in benzene are actually substituted by chlorine,
bromine, etc. The derivatives of benzene may more or less readily
he re-converted into benzene, a fact supporting the close structural
or constitutional relationship existing among them,
A number of well-known substances possessing aromatic odors
were among the earliest known derivatives of the benzene series
of hydrocarbons, hence the benzene series was originally termed
the aromatic series of organic compounds.
Benzene or Benzole.
Benzene, C,H, (commonly known as Benzole )', is obtained com-
mercially from the portion of coal tar distillate boiling below
‘Note.—The student must avoid confusing coal-tar benzeac, Cale, with
petroleum benzin, petroleum ether, benzolin, ete., ( Petrolewn Spirit, B. P.),
which are mixtures of paraffin hydrocarbons of lower boiling-points.
Petroleum Beuzin (U. 8. P.), CsHis, CoH, and other hydrocarbons of the
paraffin series (of boiling-point 113-140° F.), require six times their volume
of aleohol for solution, whereas benzene, CaHe, dissolves in less than its
own volume, Specific gravity of benzene about 0,871; of benzin 0.688 to
0,660,
BENZENE. 407
100° C. This distillate is partially purified by shaking succes-
sively with sulphuric acid, water, and sodium hydroxide, and then
redistilling ; the product still contains large quantities of toluene
and other impurities, If pure benzene is required, the liquid must
be cooled by means of a freezing mixture, when the benzene erys-
tallizes out, leaving some impurities in solution ; the crystals are
well drained. Bromine is then added to the liquid resulting from
the melting of the crystals, until a permanent coloration results.
The liquid is again washed with sodium hydroxide, and distilled.
Benzene (U.S. P.) boils at 80,4°C. It is a colorless, limpid, highly
refractive liquid, of sp. gr., 0.871 at 25°C, It is a valuable
solvent of fats and oils, and under the name of ‘‘ Benzine Collas’’
was introduced by M. Collas in 1848 for cleansing purposes.
Benzene may be obtained from benzoic acid by heating with
lime. It is also formed on passing acetylene through red-hot
tubes.
When acted on by chlorine and by bromine, in the presence of a
little iodine, benzene yields all derivatives from monochloro- and
monobromo-benzene (C,H,Cl and C,H,Br) to hexachloro- and hexa-
bromo-benzene (C,C), and C,Br,). Benzene also forms iodine and
fluorine derivatives, mitro-derivatives, etc.
Nitrobenzene (nitrobenzole, artificial oil of bitter almonds,
or essence of mirbane), C,H.NO,, is obtained by slowly mix-
ing fuming nitric acid, or a mixture of nitric and sulphuric
acids, with benzene, the vessel being kept cool by immersion
in water. I[t is a yellow liquid heavier than water, having a
strong odor resembling that of oil of bitter almonds. When
acted on by a powerful reducing mixture such as iron and
acetic acid, or tin and hydrochloric acid (yielding nascent
hydrogen), is converted into aniline
Aniline or Phenylamine, C,H,NH,.'—Mix 13 parts of iron
filings, 7 or 8 of ordinary acetic acid, and 31 of nitrobenzene,
in a large flask (with an upright condenser) placed on a
water-bath, and, after the mixture has digested for several
hours, pour off the supernatant liquid from the deposit of iron
filings, and distil in a current of steam. By this method the
nitrobenzene yields, first, aniline, distilled over as a yellow oil,
and afterward a red oil, which is a mixture of azobenzene,
C,H..N —N.C,H., hydrazohenzene, C,H,.NH.NH.C,H,, and
C,H.N.
azoxy henzene, { A,
CH, N-
' Aniline may be obtained from indigo, hence its name, anil being Portu-
guese for indigo.
408 ORGANIC CHEMISTRY.
Aniline, C,H,.NH, (mixed with toluidine, C,H,NH,), when oxi-
dized by arsenic acid, or chlorinated lime, produces rosaniline,
C,,H,,N,, whose salts and derivatives form a number of the well-
known aniline colors.
Constitution of Amines.—Amines are usually regarded as deriva-
tives of ammonia, one, two, or three atoms of hydrogen being
replaced by one, two, or three univalent organic radicals, or equiv-
alents of radicals of higher quantivalence, The products are called
primary, secondary, and tertiary amines, The class includes certain
alkaloids,
Amides result when NH, displaces OH of the COOH group in
acids, Acetic acid is CH,,. OO, OH; hence acetamide is CH,.CO.NH,.
Aniline boiled with glacial acetic acid yields phenyl-acetamide, or acet-
anilide (Acetanitidum, U. 8. P.) or ‘‘antifebrine’’ C,H,.N H. C,H,0.
Acetanilide is a febrifuge and a rival of antipyrin,” phenyl-
ee ne or phenazone (Antipyrina, U. & P.)
C,,H,,N,O, or C,H .(CH,),C,NH,0, prepared by the interaction
of phenylhydrazine or aniline and aceto-acetic ether and methyla-
tion of the product. Monobrom-acetanilide, C.A,Br. NH.C,H,0,
is a sedative and febrifuge. Acetphenetidin (Acetphenetidinum,
U. 8. P.) or para-acetphenetidin, or phenacetin, CjH,.OC,H;,.NH.
C.H,0, is another febrifuge. Phenocoll is amido-aceiph enctdin,
C H,.OC,H,. NHCOCH,NH,. Du/ein, NH,CONH.C,H,.OC,H
or ‘dra-phen netol-carbamide is n substance possess nye an exe ‘eedingly
sweet taste, and has been proposed for use, like saccharin, in place
of sugar,
Acetanilide occurs in colorless, inodorous, glistening, Jamellar
crystals, having a slightly pungent taste, Melting-point, when
dry, 235.4° F, (113°C,), It issoluble in 18 parts of boiling water,
and in 2.5 parts of alcohol (and in 179 parts of water at 25° C.,
freely soluble in efher, benzol, and chloroform. If acetanilide be
heated with solution of potassium hydroxide until the odor of aniline
is given off, and the liquid be then warmed with a few drops of
chloroform, the unpleasant and penetrating odor of phenol-isonitrile
(isocyanide) is developed; and an aqueous solution mixed with so/u-
tion of bromine gives a whitish precipitate (distinctions from acet-—
phenetidin). Heated with free access of air, it burns , leaving no
residue. With sulphuric acid or with cold nitrie ae id it forms a
colorless solution, A cold saturated aqueous solution does not
affect solution of litmus (absence of free acid) and is not affected by
test-solution af ferric chloride (absence of acetone, antipy rine, und
sults of aniline),
Toluene, or methyl-benzene (commerce ially known as Toluol),
C,H.CH,, forms the principal portion of the coal-tar distillate
boiling hetween 100°-120° C,; it may be made synthetically by
ac ting with sodium on a mixture of monochlorobenzene and methyl
jodide,
0,H,Cl + CH,I + 2Na= C,H,CH, + Nal + NaCl,
CONSTITUTION OF THE BENZENE SERIES. 409
It is also obtained by the dry distillation of tolu balsam, It is an
inflammable, highly refractive liquid, boiling at 111°C. Tt may
be directly oxidized to benzoic acid, '
20,H,CH, + 80, = 20,H,COOH + 2H,0.
Having both a phenyl (C,H,) and a methyl (CH,) group in its
molecu le, it forms two sets of isomeric derivatives : one (a) in which,
by acting on toluene in the cold, the atoms of hydrogen are dis-
oar in rt sea group, and the other (4) in which, by acting
on bouing toluene, the atoms of hydrogen in the methyl
are displaced. oh mete Ne
! I,.
Dichlorotoluene, | C,H.Cl.CH,.
Monochlorotoluene, CgH,CLCE
a
Trichlorotoluene, C,H, Cl,.CH,,
Benzyl chloride, CgH,,CH,C1.
4» Benzylidene chloride, C,H,.CHCL,
| Benzotrichloride, Cy Hy,.CC,.
Benzylidene chloride, CLH,CHCI1,, when acted on by glacial
acetic acid and zine chloride and water, yields benzaldehyde,
C.H.COH (Jacobsen). By acting on benzotrichloride, O,H,.CCI,.
with water in sealed tuhes, benzoic acid results,
C,H,CCl, + 20,0 = C,H,COOH + sHCl,
Cymene, UF... para-methyl-isopropyl benzene,
C,H, (CH,)\C,H,)
occurs in several volatile oils, and is readily obtained by the re-
moval of hydrogen from the terpenes (C,,H,,) of those oils.
CONSTITUTION OF THE BENZENE SERIES,
The fact that benzene forms three addition compounds with
ehlorine, C,H,Cl,, C,H,Cl,, and C,H,Cl,, one molecule uniting with
not more than aix atoms of chlorine, and that it affords no isomeric
monosubetitution derivatives (but only one toluene, C,TLCH,, one
benzoic acid, C,H .COOH, etc.), led Kekulé to represent benzene
by the following figure (a), in which each carbon atom is assumed
to be three-fourths linked to adjacent carbon atoms and one-fourth
linked to hydrogen (the benzene ring) :—
ORGANIC CHEMISTRY.
Fig. b. Fig, ¢.
HCl
C
S™.
HC CH
ci} | cl
HC CH
Cl \y Cl
C
HC]
Benzene hexachloride
In a monosubstitution derivative such as chlorobenzene, C,H.O1,
no matter where the chlorine atom is represented, it always bears
the same relation to the benzene nucleus; hence there can be only
one variety of such a derivative. The experimental evidence of
the truth of this inference is as follows. Displace H in benzene
by aradical, X, and obtain C,H,X. In the latter displace H by
Y and obtain C,H,XY. Now displace X by H and obtain C,H,Y.
Lastly displace Y by X and obtain C,H,X. The first C,H,X and
the second C,H,X are identical in properties, yet presumably the
X in the latter is in a different position from that in the former;
whence we conclude that actual position matters nothing if relative
position is unchanged. Such hydrocarbons are symmetrical, Such
mono-X compounds are unsymmetrica/, Further displacement of
H by X in C,H,X results in more than one variety of C.H,XX, In
dichlorobenzene, O,H,Cl,, the atoms of chlorine may (represent-
ing benzene, for the moment, by a hexagonal figure (6), and assum-
ing that the carbon atoms are at the angles) be placed either at 1
and 2, Land 8, or 1 and 4, the chlorine atoms being linked to
carbon atoms which are adjacent to each other in the benzene
nucleus (ortho-posistion) ; separated from each other by one inter-
vening carbon atom (meta-position) ; or separated from each other
by two intervening carbon atoms (para-position), So with other
di-derivatives. In trichlorobenzene, C,H,Cl,, the atoms of chlorine
may be placed at 1, 2, and 8; 1, 2, and 4; or 1, 3, and 5; 1, 2,
and 4 being the same as 1, 3, and 4; 1, 2, and 3, the same as 1, 6,
und 5, ete, ; that is to say, the chlorine atoms must all three be
linked to adjacent carbon atoms, or two may be linked to adjacent
carbon atoms while one is linked to a carbon atom separated from
these by an intervening carbon atom, or all three may be linked
to carbon atoms which are separated from one another by inter-
vening carbon atoms. So with other (ri-derivatives, Hence,
theoretically, there can only be three isomeric dichlorobenzenes
and three trichlorobenzenes, and this has been verified by experi-
ment. For other illustrations, see pp. 486, 457),
ANTHRACENE SERIES. 411
Benzene addition compounds.—The double linkages represented
in the formula for benzene (fig, a), may be compared with those
in the formuls for olefines. As in the case of the olefines they
indicate a condition of non-saturation and the capacity for form-
ing addition compounds. It has been stated already (p. 406) that
benzene can unite directly with two, four, or six atoms of chlor-
ine ; the product in the last case is benzene hexachloride, C,H,Cl
(fig. ¢). Other addition compounds can also be obtained, such
as hexahydrobenzene, C,H,,, which is formed when benzene is
heated for some time at a temperature of 260° OC, with hydri-
odic acid,
Other Series of Hydrocarbons.
The Naphthalene Series, C,H, ,,- at)
Naphthalene, C,H, (Naphthalenum, U. 8. P.) is the chief
member. It is a white crystalline substance, existing in coal tar,
By oxidation it yields phthalic acid, C,H,(COOH),, the anhyd-
ride of which, C,H,| es fused with phenol, forms Phenol-
pithalein, used as an alkalimetric indicator, With other phenols
various colored compounds are produced; for example, with
resorcinol fluorescein, which, treated with bromine, gives eoain,
These compounds are termed phthaleins. Naphthalene is
employed for increasing the luminosity of coal gas. Of the two
naphthyl alcohols, a and § naphthols or monoxynaphthalenes, C,H,
(OH), S-naphthol, a powerful antiseptic, is official (Betanaphthol,
U. 5. P.).
a. ,
J ;
The Anthracene Series, CH, ,,.
A
CH.
Anthracine,C, H,, or CA % - C,H » 18 the only noteworthy
member of this series, its importance being due to the fact that
artificial madder, or alizerin, is formed from it by the following
reactions :— Anthracene is first converted into anthraquinone,
co
C,,H,0, or CH. C,H, by oxidation, By acting on anthra-
C1)
quinone with fuming sulphuric acid, it is easily converted into
a derivative, which yields potassium alizarate when fused with
potassium hydroxide,
412 ORGANIC CHEMISTRY,
Chrysophanic acid and the aloins are related to anthraquinone ;
chrysophanie acid being a dihydroxy-derivative of methylanthra-
quinone, and the aloins yielding on oxidation aloxanthin or tetra-
hydroxy-methylanthraquinone,
Chrysophanic Acid.
co
This yellow acid, C,,H,,0, or C,H,(OH),< SC, H,CH,,
004
is found in various species of rhubarb-root (Ahewm, U.S. P.),
and, under the name of pariefinie acid, in various common yel-
low lichens, Kubly and also Dragendorft consider that the
chrysophanie acid of rhubarb is only produced when a glucoside,
chrysophan, is acted on by a ferment in the presence of water. The
formation of chrysophanic acid is probably, in most if not in all
eases, preceded by the occurrence of chrysophan, or an allied sub-
stance. The author obtained it from araroba.,
Chrysophanie acid may be obtained in crystals of a golden-
yellow color, hence the name (from xpvade, chrusos, gold, and
daivw, phaind, I shine), Its synonyms are Rhaponticm, Rheie
acid, Rheumin, Rhubarbarie acid, Rhubarbarin, Rumicin. By
the reducing action of hydriodic acid it yields chrysarobin.
Chrysophanic acid, actual or potential, black and red-brown
resins (Aporetin, Pheoretin), Emodin, Rhein, and a tannoglucoside
are considered to be the conjoint source of the therapeutic prop-
erties of rhubarb. rythrorefin is merely a mixture of chryso-
phanic acid, emodin, and rhein, Chrysophanic acid and emodin
(see below) are respectively di- and tri-oxymethylanthraquinone,
Rhein (C,.H,,0,, Hesse ; C,,H.O,, Tschirsch and Heuberger) was
regarded by "Hesse as tetraoxyme thylanthraquinone, but appears
to conform rather to the second formula given above. Chryso-
phanic acid may also be obtained from several species of Rumex or
dock. ‘‘Rumicin’’ is a preparation of tog dock. Chscara
Sagrada, or Sacred Bark (Rhamnus £ urshiana, U. 8. P. ), aceord-
ing to Limousin, contains chrysophanic acid, a pt (7), and
a ferment, various resins being also said to be present,
Emadin C\H,,O,, 28 indicated above, is closely related to chry-
sophanic ac ‘id, It is obtained along with chrysophanic acid im the
preparation of the latter from rhubarb. It also occurs in black
alder bark, according to Lieber rmunn and Waldstein. It issaid to
be derived, together with glucose, from Jrangulin, C,H, Q,, the
glucoside of the dried bark.
Chrysarobin.
This compound occ “LPs in ari aroba, a substance found in cavities
in the trunk of a leguminous tree (Yonacapona araroba), Ara-
roba is also known as Goa Powder, Bahia Powder, Brazil Powder,
and Ringworm Powder. C hrysarobin ( Chrysarobinum, U, 8, P.),
ALOILNS,
(OH):
Cutts
CH—
roba by extracting with hot chloroform, evaporating to dryness and
powdering. By aeria! oxidation in alkaline solution it is con-
verted into chrysophanic acid.
C,,H,,0, or C,H,(OH), O,H,CH,, is obtained from Ara-
Aloins.
Aloine—The aloes of pharmacy (Aloe, U. 8. P.) is an evapor-
ated juice, doubtless much altered by the temperature to which it
is subjected. Purified aloes (Aloe Purificata, U. 8. P.), is obtained
from aloes by melting on a water-bath, adding alcohol, straining,
and evaporating. Aloes contains a yellow crystalline substance,
Aloinum, U.S. P., perhaps slightly varying chemically, but not
medicinally, as derived from the respective species of aloes. Aloin
is not very soluble in cold water or alcohol, but readily soluble in
these fluids on heating. Dissolved in alkalies it rapidly absorbs
oxygen, but it is not readily altered in neutral or acid solutions.
Aloin may readily be obtained from aloes by warming the latter
with three or four times its weight of amyl alcohol; pouring off
the solution; allowing it to stand for a few hours to crystallize ;
und washing the deposited aloin with ether or carbon disulphide
to remove resinous matters.
Barbaloin, —This substance, first obtained by T. and H. Smith,
occurs in minute crystals in Barbados aloes. It yields substitu-
tion compounds when acted on by bromine and chlorine, Boiled
for some time with concentrated nitric acid, barbaloin gives,
together with oxalic and picric acids, a yellow substance, chry-
dammic acid, which furnishes beautiful red salts (Tilden). Anth-
racene, ©,,H,,, has been obtained by the reduction of barbaloin,
Teobarbaloin, C,,H,,0O, (Léger), accompanies barbaloin in Bar-
bados, Curacao, Jefferabad aloes, By oxidation with nitric acid
it yields a substance apparently identical with chrysammic acid.
It ia much more easily oxidized than barbaloin, and with cold
concentrated nitric acid it gives the red coloration (Klunge’s
renction) hitherto attributed to barbaloin,
Nataloin, —This substance was discovered by Fliickiger in Natal
aloes. It crystallizes readily in rectangular plates, either from
aleohol or from water. No bromine or chlorine substitution deriv-
atives have yet been formed, but an acetyl] compound has been
analyzed (Tilden). Nataloin moistened with nitric acid givesa
red coloration which does not fade. When boiled with nitric
acid it yields no chrysammic acid, but only oxalic and picric
acids,
Homonataloin, C,,H,,0,,, occurs along with nataloin in Natal
aloes, According to Léger it is a lower homologue of mataloin,
414 ORGANIC CHEMISTRY.
from which it can be separated by fractional crystallization from
methyl! alcohol.
Socaloin or Zanaloin,—Histed and Fliickiger have shown that
Socotrine or Zanzibar aloes yields an aloin distinct from those
just described. It forms tufted acicular prisms. Nitric acid
scarcely alters the color of socaloin, Neither socaloin nor barba-
loin affords any color when vapor from a glass rod moistened with
nitric acid is allowed to come into contact with a drop of coneen-
trated sulphuric acid containing a minute fragment of the aloin,
while nataloin gives rise to a blue coloration,
EK. von Sommaruga and Egger (‘‘ Pharmacographia ’’ arrived
at the conclusion that the aloins form an homologous series, and
that they have the composition indicated in the following formulm ;
Socaloin, C,H,.O,; Nataloin, C,H,.O,; Barbaloin, C,H,,0..
Tilden’s subsequent experiments indicate, however, that" bebe:
loin and socaloin are inosmetric in the anhydrous state, but that
socaloin and its derivatives in the hydrous condition contain more
water of chrystallization than barbaloin. Nataloin is less soluble
than the otheraloins, Its formula, according to Léger, is C,,H,,0,,.
It does not yield either chrysammic or chloro- or bromo-deriva-
tives. According to Groenwold the formula for the aloin from the
aloes of Barbados and Curagao is C,,H,,O,, and that from Natal
aloes C,H,O,,. The formula officially accepted for Barbaloin is
ral
O,,H,,0 3H,O, but Léger (1908) gives it the formula C,,H,,0,.
7
QUESTIONS AND EXERCISES,
What is the formula of benzene? How is benzene artificially and
commercially prepared ?—Construct an equation explanatory of the pro-
duction of aniline.—What is the relation between toluene and benzoric
acid ?—Give the formule of naphthalene and anthracene.—Explain by
equations the production of alizarin or artificial madder.—Mention the
coloring principle of rhubarb.—To what is rhubarb considered to owe
its medicinal activity ?—Give tests for distinguishing the aloins.
The student is referred to the accompanying table for a general
view of the relations of four series of hydrocarbons (the parafiin,
naphthalene and anthracene series) to each other. Three mem-
bers of the paraffin series are shown, two of the benzene series,
and one each of the naphthalene, and anthracene series, Beneath
each hydrocarbon are given some examples of its chief deriva-
tives. A glance along the table shows the relation of these deriva-
tives to each other,
>ARAFFIN, -
i
—- ———
|
| Ethy!-
| CiusHio Anthracene
ce ee
ard ‘
tide or Iso- |
oe ae Anthracene chloride
dle a CisHeCl Vonlsneathnare
|
hes oh tae
i
byl ‘KTeuhel
irbinol im
bos Alcohol ' C1sHe.OH esther alcohol
] carbinol
t a
‘col | ‘ Anthraquinol or Di-
leo CuHsOH | hydroxyanthracene
ool
Lhyde
i ;
he
lor Propy!
me
or Ethyl-
1
br Hvyvdroxy-
bid i!
: a eat)
Dihvdroxy- |
id a!
oi cepe sie
! .
i oan |} ieee oF
| ;
cuouipiled by Dunstan.
“itis really a @
ane
Se ew
TERPENES,
THE TERPENE SERIES OF HYDROCARBONS.
The terpene series have the general formula, C,H,,,. Tereben-
thene or pinene C,,H,, (pure oil of turpentine), is the most common
member of the series,
The hydrocarbons called terpenes, C,,H,,, are very commonly
met with as constituents of the volatile oils, Very few of these
oils have been produced artificially. Their fragrance is chiefly
due to the non-terpenoid constituents (Wallach), They differ
from one another in the extent to which they rotate the plane of
polarization of light, and also in the sense of the rotation (i. e.,
right or left). They may be divided into classes, of which several
are interesting in pharmacy: (a) Terpenes or pinenes, boiling
at about 156° C., and found in ordinary turpentine and other
volatile oils ; (6) sy/vestrene, found in Russian and Swedish tur-
pentine ; (c) phedlandrene, lwvo-rotatory (left rotating) from Phel-
landrium aquaticum, and dextro-rotatory (right rotating) from the
£. amygdalina variety, chiefly, of Eucalyptus oils (p. 468), boiling
point 170°C.; (a) cifrenes (dimonenes), boiling at about 175° ©.,
and derived from the different species of citrus; (c) dipentene,
found in some turpentines and oils of camphor and elemi ; (/) ¢er-
pinene, occurring in oils of cardamoms, Camphene, fenchene and
terpinolene are terpenes, camphene occurring naturally in certain
oils. The sesquiterpenes have the formula C,,H,, and include ead-
inene, found in oils of cubebs, savin, cade, betel: camphor, galba-
num, patchouli, juniper, asafetida, hop, and olibanum ; ceryo-
phyllene, found in oil of cloves ; and other isomers of these. They
boil at a much higher temperature than the terpenes, but re-
semble them in other respects.
Oil of Turpentine (Olewm Terebinthine, U. 8. P.), Turpentine
itself is really an oleo-resin of about the consistence of fresh
honey. It flows naturally or by incision from the wood of most
coniferous trees; larch (Pinus Larix) yielding Venice Turpentine,
Abies balsamea furnishing Canadian Turpentine or Canada Balsam
( Terebinthina Canadensis, U. 8. P.), the bark of Pistachia terebin-
thus, the variety termed Chian Turpentine (containing about |
part of essential oil to 7 of resin), and Pinus australia (palustris),
P. Abies, P. pinaster and P, teda, affording the common Ameri-
can Turpentine, (7erebinthina, U. 8, P.). Pinus maritima gives
the French or Bordeaux Turpentine, and /. picea the old fragrant
Strasburg Turpentine. By distillation with-steam, the crude tur-
pentine is separated into colophony, rosin or resin, which remains
in the still, and essential oi! of turpentine, often termed simply ter-
pentine, epirit of turpentine, or “‘turpa,’’ which distils over.
Mixed with alkali to saturate resinous acida, and redistilled in a
current of steam, oil of turpentine furnishes about 80 percent. of
reetified oil of turpentine (Oleum Terebinthina: Rectificatum, U.S. P.).
416 ORGANIC CHEMISTRY.
Pinus Sylvestris and P. Ledebourii furnish Russian turpentine
(which, according to Tilden, consists of two terpenes and cymene)
and also (Wallach) a left-rotating limonene. This turpentine is prob-
ably a by-product in the preparation of common wood far (Pir
Liquida, U, 5. P.); its odor is very pleasant, quite different from
that of ordinary turpentine, The leaves of the Pinus sylvestria, or
Scotch fir, are in Germany broken down to a woolly condition,
producing Pine Wool or Fir Wool, or wadding used in making
vermin-repelling blankets ; and this substance, or, still better, the
fresh leaf, by distillation with water, yields Fir- Wool Oil, consist-
ing, according to Tilden, of two terpenes, like those of Russian tur-
pentine and cymene. The oil distilled from the fresh leaves of Pinus
Pumilio is official (Oleum Pini,U. 8. P.). The terpene of Bordeaux
turpentine (terebenthene) rotates the plane of the polarization of
light more than the terpene of American turpentine, and in the
opposite sense—i, ¢., to the left.
Oil of turpentine boils at about 320° F. (160° C.), and almost
entirely distils below 356° F. (180° C.), little or no residue re-
maining, whereas petroleum spirit, with which turpentine might
be mixed, covers a much wider range of temperature during its
distillation, Petroleum spirit also, when the small round flame
of the end of a piece of twine is brought near to some of the spirit
in a cup, gives a momentary flash of fame at a much lower tem-
perature than that at which turpentine flashes, Tested in the
especially arranged flash-point apparatus of the last Petroleum Act.
Boverton Redwood found that the flash-point of turpentine was
lowered 10° F, by 1 percent. of petroleum spirit. The specific
gravity of oil of turpentine is from about 0.860 to 0,870,
Under the influence of heat and sulphuric acid or other chem-
ical agents, pure oil of turpentine, C,,H,,, yields many derivatives
of considerable chemical interest. Among them are two optically
inactive terpene isomers named ferebene and colophene, used for
inhalation and as disinfectants and deodorizers. When acted on
by gaseous hydrochloric acid, the product is a white crystalline
monohydrochloride, C,,H, HCl. In sunlight and in presence of
moisture it slowly undergoes oxidation and hydrolysis, forming a
crystalline substance, C,,H),0,. Bromine acts violently on tur-
pentine and terpenes, giving rise to dibromides which yield
cymene when heated, C. .H,, Br, = 0,,H,, + 2HBr. Crystals of
terpin hydrate (Terpini Hydras, U. 8. P.), ©,,H,(OF),, H,0, also
ferpinol (C,,H,,),,H,O, are used therapeutically instead of terebene.
The official terebene ( Terebenum, U.S. P.), is “a mixture of
dipentene and other hydrocarbons,’’ It boils at 311° to 829° F.
(155° to 168° C.).
ALCOHOLS.
Alcohols are the substances produced when one or more hydro-
gen atoms of the hydrocarbons are displaced by one or more
ALCOHOLS. . 417
hydroxyl (OH) groups, forming (a) monohydroxyl derivatives
(monohydric or monatomic alcohols)} (6) dihydroxy! derivatives
(dihydric or diatomic alcohols), etc. ; they are in fact hydroxides
of hydrocarbon radicals, just as potassium hydroxide, slaked lime,
etc., are hydroxides of metallic radicals, thus :—
0,H,OH KOH
Eth yt hydroxide Potassium hydroxide
C,H (OH) Ca(OH
Ethylene bydroxiac or glycol Calcium h droxide
C.H,(OH Bi(OH),
if
: hi
Glyceryl hydroxide, oF glycerin Bismuth hydroxide
Monohydroxyt Derivatives of Hydrocarbons ; Monohydrie or Mon-
atomic Alcohols,
The Ethyl Series af Alcohols, C,H,,,,OH.—The alcohols, or
carbinols (Kolbe), are primary, secondary, or tertiary, according as
the hydyroxyl group is linked to a primary, a secondary, or a
tertiary carbon atom ( see p. 381). Thus :—
H C,H, 41 CL yay CL 4:
> i = |
7 j
H—C—OH H—C—OH ,*—C—OH .# —C—OH
i oS atl
H oa: rh: RE
Carbinol Typical primary Typical secondary Typical tertiary
carbinol carbinol carbinol
-
On oxidation, primary alcohols yield first aldehydes and then
acids, the CH,OH group of an aleohol becoming COH in the
aldehyde, and COOH, or carboxy, in the acid ; secondary alcohols
yield ketones, the CHOH group becoming CO, or carbonyl (as in
acetone CH,—CO—CH,), and by further oxidation break up,
forming acids with fewer carbon atoms than the original alcohol ;
while the tertiary yield a ketone and an acid, The primary
alcohols alone are of practical interest to medical and pharmaceu-
tical students. The tertiary alcohols are said to be depressants
instead of stimulants, For examples of primary, secondary, and
tertiary alcohols, see pp. 424 and 425.
General Method of Preparing Primary Alcohols,—By acting on
the monochloro-derivative of a paraffin with potassium or silver
acetate, an ethereal salt (or ester) is produced, which when saponi-
fied with potassium hydroxide yields the alcohol. For instance—
O,H,Cl + AgC.H,0, = C,H,C,H,0, 4 Ag(l
Ethy! Silver Ethyl Silver
chloride acetate acetate chloride
C.H.C,H,O, + KOH = C,H,OH + KC,H,O,
Ethyl Potassium “thy Potassium
acetate hydroxide aleohol moe tite
418 ORGANIC CHEMISTRY.
If the chloro-derivatives were directly acted upon by the potas-
sium hydroxide, hydrocarbons of the olefine or acetylene series
would result,
The chief primary alcohols are ordinarily obtained otherwise
than by the above general method.
Methyl Alcohol.
Methyl! (é@v, methu, wine, and tay, ule, wood) Alcohol, or
Carbinol, Methyl! Hydroxide, CH,OH, is a product of the destruc-
tive distillation of wood, occurring in Pyrowylic Spirit or Wood
Naphtha, and is now obtained in large quantities as a by-product
in the manufacture of beet sugar, By oxidation it yields formic
acid (see p. 325),
Methylated Spirit.—Alcohol of about 84 percent. strength, con-
taining 10 percent. by volume of wood naphtha, constitutes mefhy-
lated spirit, a spirit issued duty free in Great Britain, for the use
of manufacturers, the methyl alcohol, etc., not interfering with
certain technical applications.
Detection of Methyl Alcohol in Presence of Ethyl] Alcohol,—_
Three or four methods have heen proposed for the detection
of methyl alcohol in alcoholic liquids, in the preparation of
which methylated spirit should not be used. The method
official in the U.S, P. depends upon the conversion of part
of the methyl alcohol into formaldehyde and the recognition
of the latter. Into a test-tube of about 40 Ce, capacity, 1 Ce.
of the alcohol or spirit tobe tested is poured, and, if undiluted,
it is made up to 10 Ce, by adding distilled water. The pro-
portion of alcohol present should not exceed about 10 pereent.
by volume. A copper wire spiral (made by winding 1 meter
of No. 18 copper wire closely around a glass rod 7 Mm. thick,
making a coil about 3 Cm. long, the end of the wire being
formed into a handle) is heated to redness in a flame free
from soot, and is then plunged steadily quite to the bottom of
the liquid in the test-tube and held there for a second or two.
This treatment is repeated five or six times, the test-tube being
immersed in cold water to keep down the temperature of the
liquid. The liquid is then filtered into a wide test-tube and
very gently boiled. Ifthe odor of acetaldehyde is percepti-
ble, the boiling is continued until this odor ceases to be clearly”
noticeable, The liquid is cooled, and 1 drop of a solution
containing 1 part of resorcinol in 200 parts of water is added
to it. <A portion of this mixture is then introduced cautiously
into a test-tube containing pure sulphuric acid so as to form a
METHYL ALCOHOL,
layer upon the surface of the latter; the whole is allowed to
stand for three minutes and the tube is then slowly rotated.
No rose-red ring should show at the interface, indicating the
absence of more than 2 percent. of methyl alcohol.
Another method of detection often used by pharmacists is
that of J. T. Miller. For the application of the test to tine-
tures and similar alcoholic mixtures, some of the aleohol is first
separated by distilling off a drachm or so from about half an-
ounce of the liquid placed in a small flask or a test-tube having
a long bent tube attached, Into a similar apparatus put 30
grains of powdered potassium dichromate, half an ounce of
water, 25 minims of concentrated sulphuric acid, and 50 or 40
minims of the distillate to be tested. Set the mixture aside for
a quarter of an hour, and then distil nearly half a fluid ounce.
Place this distillate in a small dish, add a very slight excess
of sodium carbonate, boil down to about a quarter of an ounce,
add enough acetic acid to impart a feeble but distinct acid
reaction, pour the liquid into a test-tube, add a grain of silver
nitrate dissolved in about 30 minims of water, and heat gently
for a couple of minutes. If the liquid then merely darkens a
little, but continues quite translucent, the spirit is free from
methyl aleohol; but if a copious precipitate of dark-brown or
black metallic silver separates, and the tube, after being rinsed
out and filled with water, has a distinct film of silver adhering
to it, which appears brown by transmitted light (seen by hold-
ing it against white paper), the spirit is methylated. The
experiments are best performed by daylight.
Miller’s test depends for its action on the reducing powers of
formic acid. In the above operation, the ethyl alcohol becomes
oxidized to acetic acid (the corresponding acid of the ethy] series),
which «does not reduce silver salts, a minute quantity only of for-
mic acid being produced, while the methyl! aleohol yields formic
acid (the corresponding acids of the methyl series) in a compuara-
tively large quantity. Aldehyde, which is also a reducing agent,
is simultaneously produced, but is removed in the subsequent
ebullition with sodium carbonate.
Ethyl Alcohol,
Ethyl Alcohol, or Methyl] Carbinol, Ethy] Hydroxide, commonly
called simply Alcohol, C,H.OH, or CH.CH,OH,—It is a colorless
liquid, haying a boiling-point of 172.4° F, (78° C.) and sp. gr. of
0.797, Ethyl aleohol may be obtained by passing ethylene into
concentrated sulphuric acid and distilling the product, ethyl hydro-
gen sulphate, with water :— |
ORGANIC CHEMISTRY.
C,H, + Hs0, = C,H,HSO,
C.H-HSO, + H,O = C\H,OH + H,SO,
On the large scale alcohol is ke by fermentation of certain
kinds of sugar. All fermented bread retains a little alcohol, some-
times as much as | in 400,
Experiment.— Dissolve two or three grains of sugar in a
test-tubeful of water, add a little yeast (a piece of the so-called
German or dried yeast may be used), and set the tube aside
for several hours in a warm place at a temperature of 75° to
85° F. (23.8° to 29.4° C.). Carbonic anhydride is evolved,
and, if the tube be inverted in a small dish containing water,
may be collected in the upper part of the tube and subsequently
tested: the solution contains alcohol. If the experiment be
made on larger quantities (four ounces of sugar, one of yeast,
and a pint of water) the fermented liquid should be distilled,
one-half being collected, shaken with a little lime, sodium or
potassium hydroxide to neutralize any acetic acid and decom-
pose ethereal salts, and again distilled until one-half has passed
over ; the product is dilute alcohol, It may still be further
concentrated or rectified by repeated similar fractional distil-
lations. Stills can be so constructed, especially on the large
scale, as to condense and separately deliver the substances hay-
ing different boiling-points.
Fermentation.—The change known as fermentation is commonly
the result of some vital action, Alcoholic fermentation would
appear always to result from the development of a living vege-
table organism and the free multiplication of its cellular structure.
This organism is the yeast plant, Saccharomyces cerevisiae, Tn the
presence of this plant, with small quantities of phosphates and
albuminoid matter, g/uecose is converted into alcohol and carbonic
anhydride, together with small proportions of glycerin, succinic
acid, and other substances. Cane sugar, or sucrose, does not itself
undergo aleoholic fermentation. It can, however, by various
methods, be converted into glucose which is fermentable. Yeast
contains a soluble ferment, invertase, which is capable of convert-
ing sucrose into glucose, so that by the action of yeast cane sugar
may be converted into carbonic anhydride and alcohol, the soluble
ferment first conv erting the sucrose into glucose. It has recently
been shown that the action of the yeast plant upon glucose is also
due to a soluble ferment or enzyme contained in the cell and termed
symase,
CH 0, = ®2C(H,OH + 2C0.
G Hucose’ Al col 1 Carbonic anhydride
_
ETHYL ALCOHOL, 421
Not more than 20 percent. by weight of alcohol can be obtained
in a fermenting liquid, since alcohol itself prevents fermentation
when present in larger proportions than this in liquid which other-
wise would be capable of undergoing the change.
Other kinds of fermentation, arising from the action of special
ferments which have not received in all cases distinctive names,
are the following :— Viscous or Mannitic fermentation, which occurs
when beer or saccharine juices, such as that of beet-root, become
“ropy.’’ Gum, mannite, and carbonic anhydride, are produced.
For Lactic and Butyric fermentation, see pp. 332 and 458. Putre-
JSactive fermentation occurs when a liquid containing albuminoid
matter is exposed to the air, Infusoria appear in the liquid, using
up the dissolved oxygen, and the ferments of the genus vibrio are
developed, These are protected from oxygen which is fatal to them,
by a thin surface layer crowded with bacteria—small rod-like
organisms having in some cases powers of locomotion. The putre-
faction proceeds with evolution of hydrogen sulphide, methane,
and hydrogen, together with other gases having unpleasant odors
and of complex chemical constitution, For Acetic fermentation, see
“Acetic Acid.’”’ For Ammoniacad fermentation, see ‘‘ Urine.”’
Fermentation of certain Soluble Ferments or Enzymes.—For the
conversion of starch into sugar by diastase, see ‘‘Starch'’; of
amygdalin into benzoic aldehyde, hydrocyanic acid, and glucose by
emulsin, see ‘‘ Amygdalin’’ ; of salicin into saligenin and, glucose
see ‘ Salicin’’; of potassium myronate into ally! iso-thiocyanate,
etc., by myrosin (se¢ p. 427) ; of cane-sugar into grape-sugar by the
soluble ferment in yeast, see the foregoing paragraphs. Many
soluble ferments or enzymes occur in the germinating seeds and
other parts of plants, and play an important part in nutrition,
The nomenclature of ferments and fermentation is now emerging
from early confusion. The word fermentation originally described
the action that goes on in the preparation of alcoholic liquids or
of dough, for it is derived from the Latin ferveo, I boil or seethe,
in allusion to the evolution of gas. But discoveries of ferments
have #0 multiplied as to force classification, resulting in the names
organized ferments (yeast, for example), and wnorganized ferments
(such as diastase); the latter are also termed soluble ferments or
enzymes. Moreover to the action of many so-called ferments the
word fermentation is scarcely applicable, as, though otherwise
strictly analogous to fermentation, no gas is given off. Hence the
word zymosis (from Chuworc, cumosia, fermentation) for the action of
organized ferments, while the soluble or unorganized ferments are
termed enzymes, and their action one of zymo/yais,
Aleoholic Fermentation.—On the large seale the operation of aleo-
holic fermentation is carried out by the action of yeast upon mal-
tose, a variety of sugar produced from the starch present in the
secs of cereals, During germination the starch of the grain, under
the influence of a ferment called diastase which is also present, is
_
ORGANIC CHEMISTRY.
converted into dextrine and maltose, The chief reaction during
fermentation results, as already stated, in the formation of alcohol
and carbonic anhydride, though 3 percent. of glycerin, 0.5 of
succinic acid, and traces of several other substances are simulta-
neously produced (see ‘‘ Fusel Oil,”’ p, 425), By the fermentation
of yarious fruit juices and other saccharine liquids there is produced
the alcohol present in the different kinds of wine and beer as well
asin brandies, liquors, and distilled spirits generally. Orange Wine
is made by the fermentation of a saccharine solution to which
Fresh Bitter-orange Peel has been added; Sherry Wine is the
fermented juice of the grape; Whisky (Spiritus Frumenti, U, 5. P.)
is obtained by the distillation of the mash of fermented grain and
should contain from 37 to 47.5 percent. by weight of alcohol; Bay
Rum or Spirit of Myrcia is made by distilling rum with leaves of
Myrcia aeria and other plants, or by dissolving their oils in aleo-
hol ; and so on.
Alcoholic Beverages vary much in strength. Cider or apple-
wine, perry or pear-wine, and good beer (ale and porter or stout)
contain 4 to 7 percent. by volume of alcohol; good light wines,
both ‘red’? and ‘‘ white,’’ and natural sherry, 10 to 12 -percent.;
strong sherry and port which are commonly ‘‘ fortified,’’ that is,
contain added spirit, 16 or 18 percent.; while ‘‘ spirits’’ (gin,
rum, brandy, whisky, ete.), and ‘liquors’’ (ratafia, almond-
flavored ; maraschino, cherry-flavored ; curacoa, orange-flayored;
chartreuse, a composite-flavored liquor, etc.), are ‘‘ under-proof”’
or ‘‘over-proof,’’ terms explained in a following paragraph.
Vermouth is an infusion of bitter and aromatic herbs and roots in
white wine. For excise purposes ‘‘ beer’’ is any such liquid or
substitute which contains more than 2 percent. of proof spirit.
The well-known effects of these spirituous fluids on the animal
system would appear to be due primarily to alcohol, and second-
arily to esters, Some owe a part of their effect to non-volatile sub-
stances, for beer from which all alcohol, etc., has been removed
by ebullition is said to have considerable effect on the human
economy.
Spirit of French Wine (Spiritus Vini Gallici, U. 8. P.) or Brandy
is a colored or flavored variety of alcohol distilled from French
_wine. Its color is that of light sherry, and is derived from the
cask in which it has been kept, but it is commonly deepened by
the addition of burnt sugar. Its taste is due to the volatile flavor-
ing constituents of the wine, often increased by the addition of
artificial essences.
Ethyl Alcohol of Various Strengths.—A liquid containing 92.3
percent. by weight of pure alcohol, and 7.7 percent. by weight of
water, constitutes the official Aleohol, U. 5. P. Its sp. gr. is
0.816 ut 60° F. (15.6° 0.). It contains 4.9 parts by volume
of absolute ethyl alcohol, C,H,OH, and 5.1 parts by volume
of water. |
ABSOLUTE ALCOHOL.
The official Diluted alcohol (Alcohol Dilutum, U. 8. P.) contains
about 41.5 percent. by weight, of absolute ethyl alcohol and
about 58.5 percent. by weight, of water.
Another mixture containing 50 percent. by volume, of alcohol
is known in the U. 8. Inland Revenue Service as proof spirit.
Absolute Aleohol, C,H,OH (Alcohol Absolutum, U.S. P.), may
be prepared by the removal of water from less strong ethyl alcobol.
This can be accomplished, partially, by means of dry potassium
carbonate, and more completely by means of recently fused calcium
chloride. In operating on, say, one pint, 2 ounces of dry potas-
sium carbonate should be placed in a bottle that can be well
closed, and frequently shaken during two days with the spirit.
Meanwhile put rather more than a pound of calcium chloride into
a covered crucible, and subject it to a red heat for half an hour;
then pour the fused salt on to a clean stone slab, cover it quickly
with an inverted porcelain dish, and when it has solidified, break
it up into small fragments, and enclose it in adry stoppered bottle.
Put one pound of this fused calcium chloride into a flask, pour
over it the spirit decanted from the potassium carbonate, and
closing the mouth of the flask with a cork, shake them together
and allow them to stand for twenty-four hours with repeated agi-
tation, Then attaching a dry condenser closely connected with a
receiver from which free access of air is excluded, and applying
the flame of a lamp to the flask, distil about two fluid ounces,
which should be returned to the flask, after which the distillation
is to be continued until fifteen fluid ounces have been recovered.
The product should be colorless and free from empyreumatic odor;
its specific gravity should be from 0.794 to 0.7969, and it should
contain not more than 1 percent. by weight of water. It is entirely
volatilized by heat, is not rendered turbid when mixed with water,
does not cause anhydrous cupric sulphate to assume a blue color
even after the two have been well shaken together. What little
water remains may, if necessary, be removed by the cautious
addition of metallic sodium insmall quantity. If more sodium is
used than is required for all the water present, sodium ethylate is
produced by replacement of the hydroxy! hydrogen by sodium :—
2Na+ 20,H,OH=2C,H,ONa-+ H,,.
The most ‘highly purified ethyl alcohol obtainable has gp, gr.
0.7935 at 60° F. (15.5° C.), and boils at 78,3° C.,
Tests.—There are no specific tests for aleohol when mixed with
complex matters. It is, however, easily isolated and concen-
trated by fractional distillation, and is then recognizable by
noting its physical and chemical characters, Thus its odor and
taste are characteristic ; it is lighter than water, volatile, color-
' Proof epirit is so termed from the fact that in olden times a proof or
teat of its strength was afforded by moistening with it a small quantity of
gunpowder and setting light to the spirit; if it fired the powder, it was
suid to be “ over-proof'’; if not, “ under proof,”
ORGANIC CHEMISTRY.
less, and when tolerably strong, inflammable, burning with an
almost non-luminous flame ; it readily yields aldehyde (see p. 448)
and acetic ether (see p. 403), each of which has a characteristic
odor ; and in hot acid solutions, alcohol reduces potassium dichro-
mate to a green chromic salt.
According to Lieben, 1 part of alcohol in 2000 of water can be
detected by adding to some of the warmed liquid a small quantity
of iodine, afew drops of solution of sodium hydroxide, again
warming gently, and setting aside for a time; a yellowish crystal-
line deposit of iodgform, CHI,, is obtained. Under the micro-
scope the latter presents the appearance of hexagonal plates or
six-rayed and other varieties of stellate crystals.
C,H,O + 41, + 6NaOH = CHI, + NaCHO, + 5Nal + 5H,O
Other alcohols, aldehydes, gum, turpentine, sugar, and several
other substances give a similar reaction.
Tests of Purity.—Oil or resin is precipitated on diluting alcohol
containing it with distilled water, giving an opalescent appear-
ance to the mixture. Fusel oil, aldehyde, and such impurities
are detected by means of silver nitrate (see the official test of
purity on p. 628), Water in absolute alcohol may be detected by
adding to a small quantity some highly dried cupric sulphate,
which becomes blue (CuSO, 5H,O) if water be present, but
retains its yellowish-white appearance (CuSO,), if water be absent.
Note.—Most ethyl derivatives are formed from alcohol, for
example, the ethyl nitrite in spirit of nitrous ether, ethyl iodide,
etc., which have already been described. On oxidation alcohol
yields aldehyde and acetic acid.
Propyl and Butyl Alcohols.
The primary and secondary propy] alcohols, C,H,CH,OH and
(CH,),CHOH, and the four isomeric buty! alcohols, C/H,OH (see
below), are of little pharmaceutical interest.
CH,—CH,—CH, CH< one CH,—CH, CH,
as
H-_oH H—C—OH CH,—C—OH CH, —C—OH
i
H H H CHs
Prima: Primary Seconda Terti
acme Duty! iso-buty] ‘but Dy but Ne
alcohol alcohol | nloohol alcohol
The new hypnotic known as ch/oretone is a trichloro-derivative
of tertiary butyl alcohol. Its form ula is CCl,(CH,),C. OH,
Amyl Alcohols.
Amyl Alcohol,C,H,,OH, or C,H,CH,OH, is always produced
. il = P . - = = '
during the preparation, by fermentation, of ethyl or common
OTHER MONOHYDRIC ALCOHOLS. 425
alcohol, C,H,OH, especially when the latter is prepared from
sugar which has been derived from starch; hence the name,
+ from amylum, starch. The sugar from potato-starch yields a con- —__—
siderable quantity; hence the alcohol is often called potato oil.
The impure amy! alcohol obtained and separated during the
preparation of common alcohol is also termed fousel oil or fusel oil
(from yiw, phuo, to produce), in allusion to the circumstance that
the so-called oil is not simply educed from a substance already
containing it (as is usually the case with oils), but is actually pro-
duced during the operation, It was described as oil probably
because it resembled oil in not readily mixing with water ; but it
is soluble to some extent in water, and is an alcohol homologous =,
with ethyl alcohol. It often contains variable proportions of t-
propyl, butyl, and capryl alcohols. (See also Valerie Acid.) It ____-
should be redistilled for medicinal use and the product passing
over at 262° to 270° F. (or about 128° to 152° C.) should alone
be collected, = |
Purified fusel oil is a colorless liquid, with a penetrating and
oppressive odor and a burning taste. It is sparingly soluble in
water, but soluble in all proportions in alcohol, ether, and essen-
tial oils. Exposed to the air in contact with platinum black, it
is slowly oxidized, yielding valeric acid, C,H,.COOH. Eight
isomeric varieties of amyl alcohol are known, of which three
possess pharmaceutical interest. Two ofthese, viz., primary inac-
tive iso-amy! alcohol or iso-buty! carbinol and primary active amyl
alcohol, are present in purified fusel oil, the former constituting
much the larger proportion of it: the third isomeric variety is
tertiary amyl! alcohol.
CH—OH<oy OH<CH.—CH, CH,
+) a3
H H H_d_0n cn,—_on
i i of,
Primary Primary Tertiary
inactive — nckive amy! alcohol
lso-amyl alcohol amyl aleohol “Amylene hydrate”
The constitution of the variety of amy! alcohol termed ¢ertiary
amyl alcohol, or dimethyl-ethyl-carbinol, ia shown in the above
graphic formula, Itis used in medicine in place of chloral hydrate,
and is known as amylene hydrate,
Other Monohydric Alcohols.
_ Among the higher alcohols of the ethyl series are the follow-
ing :—
Cetyl Aleohol or Cetyl Hydroxide, C,H. OH, formerly termed
ethal, obtained by saponifying spermaceti (Cefaceum, U. 8. P.)
426 ORGANIC CHEMISTRY.
which consists of cetyl palmitate, C,,H,,C,,H,,O,, or cetine. Sper-
maceti is the solid crystalline fat accompanying sperm-oil in the
head of the sperm whale,
Ceryl Alcohol, O,,H.OH, is obtained in a similar manner from
Chinese-wax (cry! cerotate).
Melissyl Alcohol or Myricyl Alcohol, C,H,,OH, is obtained in a
similar manner from melissy! palmitate, the portion of beeswax
sparingly soluble in hot alcohol. Melissyl aleohol occurs in
Curnauba Wax, from Copernicia cerifera, Mart. (Corypha cerifera,
Linn.) a wax characterized by its high melting-point, 176° to
194° F, (80° to 90° C.). Yellow Beeswax ( Cera Flava, U. 3. P.)
and the same bleached by exposure to moisture, air, and sunlight,
or White Beeswax (Cera Alba, U. 8. P.) is prepared from the
honeycomb of the hive-bee. According to Brodie it consists in
the main of cerotic acid and melissyl palmitate, with about five
percent. of ceroleine, the substance to which the color, odor, and
tenacity of wax are due. Among the possible adulterants of wax
are paraffin and ceresine, The latter is the purified native ozokerile
of Galicia, a solid hydrocarbon largely used as a substitute for
beeswax, especially in Russia, Both paraffin and ceresine reduce
the melting-points of wax. The quantity of paraffin and ceresine
present as impurity may be determined by heating the wax first
with ordinary, and afterward with fuming, sulphuric acid, which
scarcely affect these adulterants. Pure beeswax will not yield
more than about three percent. ofits weight to cold rectified spirit,
whereas resin, ete., would be extracted by the spirit, Solution of
sodium hydroxide extracts nothi ng from pure beeswax, but dissolves
fatty acids, fats, resin, Japan-wax, etc., present as impurities and
the alkaline fluid then yields a precipitate of acids on the addition
of hydrochloric acid, Soap would be dissolved from wax on boil-
ing the sample with water, and the aqueous fluid would yield fatty
acid on adding hydroc hloric acid. Flour or any starch would be
detected in the cooled aqueous fluid by means of iodine. Wares
anid fa/lowe are common on leaves, fruits, and barks.
The Allyl Series of Aleohols, C,H,,_,OH.
Allyl alcohol, C,H,,OH, may ‘be obtained by heating 4 parts of
glycerin with 1 of ‘oxalic ac ‘id, the receiver being changed at
195° C., and the liquid collected until the temperature rises to
260° C. The first product is formic acid, which interacts with
glycerin, forming monoformin :—
C.H,(OH), + HCOOH = H,O + O©,H,(/OH),OCHO
Glycerin Formic acid Water Monoformin
This, on further heating, yields allyl alcohol :—
CH(OH),0CHO = H,O + CO, + GH,OF.
By the action of the halogen acids it produces iodine, bromine,
and chlorine derivatives, the OH being replaced by I, Br, or Ol;
ALLYL COMPOUNDS. 427
these derivatives, when digested with potassium thiocyanate, yield
allyl thiocyanate, C,H,CNS. This compound on distillation under-
goes isomeric change, and is converted into allyl iso-thiocyanate,
C,H,NCS, the artificial Oil of Mustard (identical with the chief
constituent of the natural oil, Olewm Sinapis Volatile, U. 8. P.).
Allyl iso-thiocyanate is the substance to which mustard owes its
power of inducing inflammatory action on the skin.
Black Mustard (Sinapis Nigra, U. 8. P.) is the powdered black
or, rather, reddish-brown mustard-seed from Brassica nigra, and
White Mustard ( Sinapis alba, U. 8. P.), is the white mustard-
seed from Sinapis alba. White mustard-seed contains sinalbin,
C,H,,.N,8,0,,, 4 glucoside which, in contact with the myrosin
present in an aqueous extract of mustard, yields iso-thiocyanate
of the radical aeriny/, a substance which forms part of the essential
oil of mustard,
H O H,O = GE - 0
waitin” * Water “hetinyl | Binaptacta Glade
iso-thiocyanate sulphate
Crude oil of mustard often contains ally/ cyanide, CA,CN,
Black mustard-seed contains the albuminoid ferment, myrosin
(resembling the emudvin of almonds), and also potassium myronate,
or sinigrin, The latter is the substance which, under the influence
of the ferment, yields the chief part of the pungent oil of mustard,
KC,,H,.NS,O, + H,O = KHSO, + C,H,NCS + O,0,
Potassium Water Acid potassium Ally) Glucose
myronate sulphate iso-thiocyanate
The quantity of myrosin in black mustard is scarcely sufficient
to decompose the whole of the sinigrin, while in white mustard
the quantity is more than sufficient to decompose the sinalbin.
Hence the most effective mustard is a mixture of white and black.
The ferments act most effectively, hence the maximum amount of
pungency is produced, in mustard paste at temperatures not exceed-
ing 100° F. (37,7° C.)
Charta Sinapis, U. 8. P., is thick, well-sized paper which has
been coated on one side with a mixture of purified mustard and
solution of India-rubber and dried.
In the old Pharmacopeia of India the seed of Brassica juncea,
Rai, or Indian Mustard Plant, is included in addition to those of
B. alba and B. nigra, tis the common mustard of warm coun-
tries. It does not differ chemically from other mustard, Allyl
compounds are also met with in several other cruciferous and
liliaceous planta. Oi! of garlic owes its odor to allyl compounds ;
experiments carried out by F. W. Semmler show these to be allyl-
propyl! disulphide, and dially! disulphide.
Deeylene Alcohol, O,,H,,OH, belongs to the allyl series, _Men-
thol (Menthol, U. 8. P.), obtained from oil of peppermint, is said
by some to consist wholly of this alcohol,
428 ' ORGANIC CHEMISTRY.
Sulphur Alcohols, or Thio-aleohols, CHSH, C,H,5H, ete., analo-
gous to hydrosulphides, KSH, etc., are known. They were
originally termed mercaptans (mercurius captans) from the readiness
with which they took up mercury to form compounds such as
(C,H,S),Hg. The vapors of thio-alcohols and many allied sulphur
compounds have an extremely unpleasant smell.
Sulphonie Acids are products of the oxidation of the sulphur
alcohols just mentioned. For example :—
2c,.HSH + 380, = 20,H,.50,.0H
Ethyl-mereaptan Oxygen Ethyl-sulphonie acid
A number of aromatic sulphonic acids may be formed by acting
on hydrocarbons with sulphuric acid, Examples :—
“Te OH - | =] C H
S80.<oqp + GH, = 50,<oy* + 430
Sulphuric acid Benzene Benzene-sulphonic acid Water
OH we Ue Otde -)
80,< OH + OF,.CH, = BO,< on” ~ ah H,O
Sulphuric acid Toluene Toluene-sulphonic acid Water
Sulphonic acids are isomeric with acid sulphites, the character-
istic sulphonic group or radical being SO,H, but the acid sulphites
of the organic radicals are extremely unstable, the corresponding
sulphonic acids very stable ; the former are easily decomposed by
potassium or sodium hydroxide while the latter are not attacked.
Sulphonmethane (Su/phonmethanum, U.S. P.), also called sul-
phonal, a hypontic, is a crystalline, colorless, tasteless, odorless,
substance, It is a product of the action of a permanganate solu-
tion on acetone-ethyl-mercaptol (CH,),C(C,H,S),—a liquid result-
ing from the interaction of hydrochloric acid, mercaptan, and ace-
tone. Its systematic name is diethylsulphone-dimethylmethane,
Sulphonethylmethane (Su/phonethy/methanum, U. 8 P.) also
called trional, is diethylsulphone-methylethylmethane, and fefro-
nal is diethysulphone-diethylmethane,
So-80,0.H, CH, _-80,0,H,
+ F 580,0,H, J. % . =f ‘,H,
Sulphonal
CH,
0,0,
_-80,C,H,
S0,C,H,
Tetronal
>C.
Saccharin ( Benzosulph inidum, U. 8. P.: synonym, Benzowulphin-
ide), which isa harmless, non-alimentary . pu rely sweeten ing agent,
two or three hundred times as sweet as sugar, is benzoyl sulphonic
imide. Fahlberg obtains it by converting toluene into toluene-
sulphonic acid (above); this into a calcium salt, then into a sodium
salt, and the latter into toluene-sulphonic chloride, by action of
phosphorus trichloride and chlorine; the liquid orthochloride
ETHERS,
into amide by ammonium carbonate ; the amide is then oxidized
by potassium permanganate to potassium sulphamidobenzoate and
water; hydrochloric acid then precipitating benzoyl-sulphonic
imide or ‘‘ saccharin '’ with elimination of water. “Soluble sac-
charin’’ is saccharin in which hydrogen is displaced by sodium.
The following formuls illustrate the stages of manufacture :-—
SO, <CyHOH, SO, eps 80,< NOH
Toluene-sulphonic Toluene-sulphonic Toluene-sulphonic
acid chloride amid
=ln _C COOK 4 Cc H CO 4 e+ i CO
BO<N 80<N 80,<NN
Potassium Benzoyl-sulphonic “ Solnble
bulphamidobenzoate amide or“ saccharin"’’ saccharin”
Orthophenolsulphonic acid, CJH,OH.SO,.OH, sozolie acid, or
aseptol, is 4 non-poisonous, nNon-irritating antiseptic, Di-iodopara-
phenolsulphonie acid, or sozoiodol, C.H,1,0H.80,.0H, has similar
properties and is used instead of iodoform.
QUESTIONS AND EXERCISES,
Give an outline of the relations between alcohols and acids.—Give u
general method of preparing the primary alcohols of the ethyl series,—
Name the source of methyl! alcohol.—What is “‘ methylated spirit " ?—
Describe the mode of detecting methyl alcohol in a tincture,—How can
artificial ethyl alcohol be prepared ?—Write a few sentences on the form-
ation, purification, and concentration of alcohol, and explain the differ-
ence between the official varieties of alcohol, proof spirit, and absolute
alcohol,—State the proportion of alcohol commonly present in malt
liquors, light wines, port and sherry, and “ spirits” ; and state the extent
to which spirits may be diluted without “ adulteration.”’"—Enumerate the
characters of alcohol.—Whence is brandy obtained, and to what are its
color and flavor due ?—Give a short account of commercial amyl alcohol.
—How is allyl alcohol prepared ?—In what relation does ally alcohol stand
to oil of mustard and oil of garlic?
ETHERS.
Ethyl Ether, or Ordinary Ether.—Into a capacious test-tube
put a small quantity of alcohol and about half its volume of
sulphuric acid, mix, and gently warm; the vapor of ether,
recognizable by its odor, is evolved. Adapt a cork and long
bent tube to the test-tube, and slowly distil over the ether into
another test-tube. Half the original quantity of alcohol now
placed in the generating-tube will again will give’ether ; and
this operation may be repeated many times,
ORGANIC CHEMISTRY.
The preparation of ordinary ether is usually performed on a
manufacturing scale. In carrying out a laboratory experiment on
a somewhat larger scale than that described in the preceding para-
graph (in imitation of the manufacturing process) the addition of
alcohol, instead of being intermittent, is continuous, a tube con-
veying aleohol from a reservoir into the generating vessel. Mix
ten fluid ounces of sulphuric acid with twelve fluid ounces of
alcohol in a glass retort or flask capable of containing at
least two pints, and, without allowing the mixture to cool, con-
nect the retort or flask, by means of a bent glass tube, with
Preparation of ether,
a Leibig’s condenser, and distil with heat sufficient to main-
tain the liquid in brisk ebullition. (If a thermometer also he
inserted in the tubulure of the retort or through the cork of the
flask, the temperature may be carefully regulated—between 284°
and 200° F. ; (140° and 143.3°C.). As soon as the ethereal fluid
begins to pass over, supply fresh alcohol in a continuous stream,
and at arate about equal to that at which the fluid distils. For
this purpose use a tube furnished with a stopcock to regulate the
supply, as shown above in Fig. 40, connecting one end of the tube
with a vessel containing the aleohol supported above the level of
the retort or flask, and passing the other end through the cork of
the retort or flask into the liquid. When a total of fifty fluid
ounces of aleohol has been added, and forty-two fluid ounces of
ether have distilled over, the process may be stopped.
To partially purify the liquid, dissolve ten ounces of caleium
chloride in thirteen ounces of water, add half an ounce of lime,
and agitate the mixture in a bottle with the impure ether. Leave
the mixture at rest for ten minutes, pour off the light supernatant
fluid, and distil it gently until the specific gravity rises to 0.785,
The ether and alcohol retained by the calcium chloride, amd in
ETHERS.
the residue of each rectification, may be recovered by distillation
and used in a subsequent operation. To imitate the process of
partial purification just described, add to the small quantity of
ether obtained in the previous test-tube experiment, a concentrated
solution of calcium chloride and a little slaked lime; the latter
absorbs any sulphurous acid that may have been produced by
secondary decompositions, while the former absorbs water; on
shaking the mixture and then setting aside for a minute or two,
the ether will be found floating on the surface of the solution of
calcium chloride.
Explanation of Process. —On mixing sulphuric acid and alcohol
in equal volumes, they interact to some extent to form ethy! hydro-
gen sulphate (sometimes termed ethyl-sulpburic, or sulphovinic,
acid) :—
OH,0H + HS0, = C,H,HSO, + 4H,0
lechol Sulphuric ‘Ethyl hydrogen Water
acid sulphate
The ethyl hydrogen sulphate interacts, on warming, with more of
the alcohol to form ether and sulphuric acid :—
C,H,OH + C,H.HSO, = (C,H,),0 + H,S80,
Su
spy, nee hyaroge = or CoH OCH
The water of the first reaction and the ether of the second distil
over, while the sulphuric acid liberated is again attacked by alco-
hol and reconverted into ethyl hydrogen sulphate. The effect,
however, of a small quantity of sulphuric acid in thus conyerting
a large quantity of alcohol into ether is limited, secondary reactions
occurring to some extent after atime. The official ether (ther,
U. 5, P.) is a colorless, very volatile and inflammable liquid,
having a strong and characteristic odor. Sp. gr. 0.716 to 0,717.
It contains about 96 percent, by weight of ethyl oxide (C,H,),O.
Properties, —Pure ethyl] ether is gaseous at temperatures above
95° F. (35° C.); hence the condensing tubes employed in its dis-
tillation must be kept as cool as possible. At all ordinary temper-
atures it rapidly volatilizes, absorbing much heat from the surface
on which it is placed. A few drops evaporated from the back of
the hand produce a well-marked sensation of cold; and if blown
in the form of spray, the cooling effect is so rapid and intense as
to produce local anwsthesia. Evaporated by aid of a current of
air from the outside of a thin narrow test-tube containing water,
the water may be frozen. Its vapor is very heavy, more than two
and a half times as heavy as air, and nearly forty times as heavy
as hydrogen, H, = 2; C,H,,0 = 74, or as 1 to 87. Inastill atmos-
phere the vapor will flow a considerable distance along a table or
floor before complete diffusion occurs, and as the vapor is highly
inflammable, it is of the greatest importance to keep candle and
other flames at a distance during manipulations with ether, Ex-
Iphuric
acid
432 ORGANIC CHEMISTRY.
posed to the action of air and light, ether undergoes some decom-
position and then contains a little hydrogen peroxide,
The official ether of the U. 5, P. is a colorless mobile liquid
having a characteristic odor and a burning sweetish taste. It is
composed of about 96 pereent., by weight, of absolute ether or
ethyl oxide, and about 4 percent. of alcohol with a little water.
It boils at about 96° F. (35.5° C.), and its ap, gr. is 0.716 to 0.717
at 77° F. (at 25° C.).
Mixed Ethers,—That C,H,—O—C,H, represents the consti-
tution of ether is indicated by the result of the reaction of, say,
methyl! alcohol on ethylsulphuric acid, a single definite substance,
methyl-ethyl ether, CH,—O—C,H,, resulting.
Ethers of various radicals, R—O—R, and several mixed ethers,
R—O—RK’, are known ; also sulphur ethers or thio-ethers, such as
(CH,),S, (C,H,),5, ete.
Spiritus theris, U. 8. P., Spirit of Ether, is a mixture of
325 parts of common ether (ther, U, 8. P.), with 675 parts of
alcohol.
Ethylene Sulphate, CHS0O,, is said to be contained in ‘* Hoff-
mann’s Anodyne, ’’ Compound Spirit of Ether (Spiritus ltheria
Compositus U, 8. P.), a solution of ethereal oif in ether and
alcohol. The so-called ‘‘ heavy oil of wine’’ is obtained by
digesting alcohol and sulphuric acid together, then distilling and
washing the oily distillate with distilled water. The product is a
mixture consisting probably of ethylene sulphate, ethyl sulphate,
ether, dissolved ethylene, and other substances. Ethereal oil,
(Oleum ASthereum, U. 8. P.) isa mixture of equal parts of heavy
oil of wine and ether.
AROMATIC ALCOHOLS (C,H,,-,OH Series.)
. Phenols.—These are alcohols in the sense of being hydroxyl
derivatives of hydrocarbons. ‘They possess in a slight degree the
character of acids, forming compounds with metals which to some
extent resemble salts. Unlike the paraffin alcohols, they do not
yield aldehydes, acids, or ketones on oxidation,
Phenol.
1 = y * - Ss . yah |
nol or potassium carbolate
yields phenol :-—
‘Ordinary carbolic acid is a mixt uré of phenol wit h cresol and other
homologues of phenol.
AROMATIC ALCOHOLS. 433
C,H,HSO, + 8KOH = ©,H,OK + K,SO, 4+ 2H,0
LL BeTVeE- Potassium Potassium Volassium Wuter
sulphonic acid hydroxide carbolate sulphite
Commercially, phenol is obtained from that part of coal-tar
boiling between 356° and 874° F. (180° and 190° C.), When
purified, it is a colorless' crystalline solid, of melting point not
lower than 104° F, (40° C.), (Phenol, U. 8. P.). A erystalline,
so-called hydrous, acid, C,H,OH,H,O, may also be obtained.
Phenol is only slightly soluble in water, but is readily
dissolved by alcohol, ether, and glycerin (G@lyceritum Phenol,
U.S. P.). At 60° F, (15.5° C.), 100 parts of the acid are lique-
fied by the addition of 5 to 10 parts of water (9 of acid and 1 of
water forming Phenol Liguefactum, U. 8, P.). At the same tem-
perature 100 parts of phenol dissolve 30 to 40 of water, and are
dissolved by 1800 to 1200 of water, the former of these numbers
being said to be characteristic of the acicular, and the latter of
the pulverulent variety of the acid. Of the small, separate crystals
which are official, 1 part dissolves in 12 of water.
At temperatures above 95° F. (35° C.) phenol is an oily liquid.
In odor, taste, and solubility (and in appearance when liquefied by
heat or by the addition of 5 percent. of water) it resembles creo-
sote, a wood-tar product for which it has been substituted.
Besides phenol, coal-tar oil contains eresol or cresylic acid
C,H,OH, or C\H,CH,OH, while wood-tar oil furnishes guaiacol,
C,H,O,—also a product of the destructive distillation of guaia-
cum-resin, boiling point 892° I, (200° C.)—and ereosol, O11,,0,,
or C,HCH,. OH.LOCH,, the mixture constituting creosote, (Cruaia-
cal (Guaiacol, U.S. P.), which may also be prepared syntheti-
cally, is a colorless crystalline solid of melting point 88,3° F.
(28,.5° C.), ora colorless refractive liquid boiling at 401°F, (205°C,)
Guaincol carbonate (Guaiacolis carbonas, U.S. P.) may be prepared
by the action of carbonyl chloride on sodium guaiacolate, Certain
coloring-matters may be obtained by the oxidation of phenol:
thas the addition of a small quantity of a solution of a hypo-
chlorite to phenol which has been mixed with ammonia or, still
better, with aniline (phenyl-ammonia or phenylamine) produces a
blue liquid. No very satisfactory chemical method can be found
for distinguishing creosote from phenol, as creosote contains phenol,
Some physical differences exist: thus, phenol does not affect the
plane of polarization of a ray of polarized light; creosote rotates it to
the left or slightly to the right according to variations in the sub-
stances present in it. Phenol is either solid or may be solidified
by cooling; creosote is not solidified at the low temperature
attained by mixing hydrochloric acid and sodium sulphate, Creo-
sote from coal (impure or crude phenol) yields a jelly when shaken
'Phenol soon assumes a pink color owing (Fabrini) tu the action of hy-
drogen peroxide and ammonia in presence of traces of copper, iron, or lead,
28
ORGANIC CHEMISTRY.
with albumin or with collodion; creosote from wood ( Creosofum,
U.S. P.) is scarcely affected, especially if quite free from traces o
phenol, Coal-creosote is soluble in solution of potassium hydrox-
ide and in ammonia water (Read); wood-creosote is scarcely solu-
ble, The coal-tar product is soluble in twenty times its
volume of water, and a neutral solution of ferric chloride pro-
duces a more or less permanent green or blue color with the
liquid ; wood-creosote is less soluble (Agua Creosoti, U, 8. P., is
said to contain 1 in 129) and is not permanently colored blue by
ferric chloride, An alcoholic solution of the coal-tar creosote is
colored brown by ferric chloride, a similar solution of wood-¢reo-
sote green. A dilute solution of creosote, such as creosote water, is
not affected by agitation with spirit of nitrous ether while a similar
solution of phenol becomes red. A few drops of spirit of nitrous
ether are placed in a test-tube with about a drachm of the
aqueous liquid, and an equal volume of sulphuric acid is poured
down the sides of the tube, A pink or red color results if phenol
be present, especially after standing for a short time (Eykman;
MacEwan). A solution of phenol gives, with excess of bromine
water, an insoluble white precipitate of tribromophenol, C,H, Br,
OH. This reaction is useful in quantitative determinations of phe-
nol. The determination of the amount of iodine absorbed by alka-
line solutions of this and other phenols (thymol, naphthol, ete.,
serves also for quantitative purposes. According to Morson pure
creosote is not dissolved when mixed with an equal volume of com-
mercial glycerin, while phenol is miscible in all proportions and, if
present in the creosote, will carry a considerable quantity of it into
solution, Creosote is, obviously, a mixture of substances and may
vary somewhat in composition.
Phenol and alkalies yield carbolates or phenates, such as
3,H,OK and C,H,ONa. Alcoholic solutions of the latter and of
mereuric chloride yield yellow crystalline mercuric phenate or
phenol-mercury, (C,H,O),H¢g.
Phenol is a powerful antisepfic (avri, anti, against and ofa, spo,
to putrefy). In large doses it is poisonous, antidotes being a
mixure of olive-oil and castor-oil, freely administered, or a
mixture of slaked lime with about three times its weight of sugar
rubbed together with a little water, Phenol is attacked by hot
sulphuric acid, sulphocarbolie or para - phenoleulphonic acid,
C,H,(OH)S80,H, being formed. On diluting the product and
mixing with oxides, hydroxides, or carbonates, phenolsulpho-
nates are formed. The formula of sodinm phenoleulphonate is
NaO,H,S0,,2H,O,or C,H,(OH)SO,Na, 2H,O. It is obtained by
heating a mixture of phenol and excess of sulphuric acid for some
time to 100°-110° ©, and converting the para-phenosulphonic acid
40 obtained into a sodium salt, by first treating the mixture with
barium carbonate, which forms insoluble barium sulphate and a
svlution of barium sulphocarbolate, filtering, and treating the
PHENOL, 435
filtrate with sodium carbonate. It forms colorless, neutral, pris-
matic crystals (Sodii Phenolsulphonas, U, 8, P.). Zine Phenol-
sulphonate, [(CJH(OH)SO.),Zn,8H,O (Zinei Phenolsulphonas,
U.8. P.), may be obtained by saturating sulphophenolic acid
with zine oxide.
Trinitro-phenol, C,H.(NO,),.OH, is formed on slowly dropping
phenol into fuming nitric acid; it is the yellow dye known as
carbazotic acid, or picrie acid, Most of the picrates are explosive
by percussion, and picric acid itself forms, when fused, the
explosive known as /yddite.
_ Both phenol and benzene are products obtained in the manu-
facture of coal-gas ; hence the word phenic and thence phenyl (from
baiva, phaind, I light, an allusion to the use of coal-gas),
By heating phenol with zinc dust, benzene results, —
C.H,OH + Zn = ZnO + C,H,
Cresol or Tolyl Alcohol, C,A,OH or C,H,OH.CH,, one of the
hydroxytoluenes, is always found in crude phenol ; artificially it
may be made by the same general method as phenol, by acting on
toluene with sulphuric acid and heating the resulting sulphonic
acid, C,H,(SO,H)CH,, with potassium hydroxide. With ferric
chloride it gives a brown coloration. The three isomeric forms,
ortho-, meta-, and para-, are known ; Creso/, U. 5.P. is a mixture
of them,
Benzyl Alcohol, Phenylearbinol, C,H,OH,OH, 1s isomeric with
cresol, but has the hydroxyl group in the methane nucleus, and
not in the benzene nucleus of toluene. Having the CH,OH group,
it yields on oxidation benzaldehyde, C,H,COH (oil of bitter
almonds), and benzoic acid, C,H,COOH.
——
Dihydroryl-Derivatives of Hydrocarbons; Dihydric or
Diatomie Alcohols.
Glycols, C,H,,(OH), series, | |
Glycols may be regarded as dihydroxy]-derivatives of the paraf-
fins, the alcohols of the ethyl series being monohydroxy|-deriva-
tives :-—
0,H, C,H,OH C,H,(OH),
Ethane Ethy] alcohol Glycol
They are prepared by acting on di-iodo-derivatives of the paraffins
with silver acetate, and then treating the product with potassium
hydroxide.
C,H, + 2CH,COOAg = (CH,COO),C,H, + 2Agl
Di-fodo-cthane silver kth ylene Silver
acetate acetate jodide
456 ORGANIC CHEMISTRY,
(CH,COO),C,H, + 2KHO = C,H (OH), + 2CH,COOK
Ethylene acetate Potassium hydroxide Glycol Potussium acetate
The glycols yield very interesting products on oxidation, form-
ing two sets of acids, the lactic and the succinic series,
Aromatic Glycols, C,H, (OH), Dihydroxyl-derivatives of
benzene,
Resorcinol (Resoreinol, U. S. P.), pyrocatechin, and hydro-
quinone :—
When two atoms of hydrogen in benzene are displaced by two
hydroxy! groups one of the three possible isomeric compounds is
resorcinol, C,H,(OH),, a colorless, crystalline antiseptic having
many advantages over phenol in surgical operations. Its name
was given in allusion to its original source, resin, and to certain
similarities with orcin. It occurs in white flat prisms readily
soluble in most liquids. It may be made by passing benzene
vapor into hot sulphuric acid and heating the product (benzene
meta-disulphonie acid, C,H,(SO0,.OH),) with excess of sodium
hydroxide.
C,H,(S0,.0Na), + 2NaHO = C.H,(OH), +
Sodium benzene Sodium Resorcino!
meta-disulphonate hydroxide sulphite
Resorcinol is one of the three isomeric dibydroxy]-benzenes,
The chemical relationships of these isomers warrant the conclusion
that the differences in their properties are due to differences in
the relative positions of the two hydroxy! groups in the molecules,
as represented by the following formulz :
C(OH) C(OH) C(OH)
HC (OH) HO OH HC CH
tek \
HC C(OH) ut CH
A
%
CH C(O)
Ortho-dihydroxy- Meta-dihydroxy-_ lpn) a
bonzene (pyrocatechin) benzene (resorcinol) benzene (hydroquinone)
These formule may conveniently be shortened as follows ;—
C.H<oH oH<0#
= Yer es .
(.H — » OH im) “é ~OH (py
os 0 I l(a)
Among the benzene or aromatic compounds there are many
similar sets of three isomeric di-substitution derivatives (three
xylenes, three phthalic acids, etc.), the occurrence of which is
in complete agreement with the ‘‘ benzene ring’’ hypothesis of
Kekulé as to the constitution of benzene compounds,
GLYCERIN,
Orein, or dihydrory-toluene, C H1,(OH),CH,, is found in lichens.
Saligenol or saligenin isa hydroxy-benzyl alcohol, salicy| alcohol,
CH jOHLCH OH. = It is obtained from the salicin of willow bark.
Having a hydroxyl group in the methane nucleus as well as in the
benzene nucleus, salicylaldehyde, C,JH,OH.COH, and salicylic
avid, C, H,OH.COOH, are formed on oxidation.
Trihydroryl-Derivatives of Hydrocarbons ; Trihydrie or
Trialomie Alcohols.
Glycerol series, C, H,,_(OH),. The only member of this series
which we shall consider here is :—
Glycerin.
Glycerol,' propenyl alcohol, glycerin, C,H,(OH),.—The pro-
penyl or glyceryl radical of glycerin in combination chiefly with
the acid radicals of oleic, palmitic, and stearic acids, forms most
of the solid fats and fixed, i.e., non-volatile oils. When these
latter substances are heated with metallic hydroxides, interaction
occurs, oleate, palmitate, or stearate of the metal is formed, and
glycerin (glyceryl hydroxide) is set free. Hence glycerin is a by-
product in the manufacture of soap, hurd candles and lead plaster.
The fats are also decomposed when exposed to the action of steam
at from 500° to 600° F. (260° to about 315° C.) glycerin and oleic,
palmitic, or stearic acid being formed.
Properties. —Glycerin, (Glycerinum, U.S. P.) is a viscid liquid
of sp. gr. 1.246; it has a sweet taste, and is soluble in water or
alcohol in all proportions, It has remarkable powers as a solvent,
is a valuable antiseptic even when diluted with 10 parts of water,
and is useful as an emollient. Under reduced pressure it may be
distilled unchanged, but at ordinary atmospheric pressure it under-
goes partial decomposition on distillation. In a shallow open
vessel heat readily vaporizes it if a little water be present. From
damp air glycerin absorbs moisture slowly, but in considerable
proportions, Perfectly pure and anhydrous glycerin, at a few
degrees below the freezing point of water, sometimes solidifies to
a mass of crystals,
Tests.—Heat one or two drops of glycerin in a test-tube,
alone or with concentrated sulphuric acid, acid potassium sul-
phate, or other salt powerfully absorbent of water ; vapors of
aerylaldehyde or acrolein (from acer, sharp, and o/ewm, oil)
are evolved, recognizable by their powerfully irritating effects
on the eyes and respiratory passages. If the glycerin be in
'Tt will be noticed that one of the names of each alcohol has the ter-
mination -o/, carbinol, glycol, glycerol, saligenol, pyrogallol,
438 ORGANIC CHEMISTRY.
solution, the latter must be evaporated to as small a volume
as possible before the test is applied.
C,H.(OH), = 2H,O + CH, : CH.COH
Glycerin Water Acrylaldehyde
To some dilute solution of borax, reddened by the addition
of phenol-phthalein, add a few drops of a solution (neutralized
if necessary) suspected to contain glycerin; if any is present,
the color will be discharged owing to the liberation of free
boric acid, but will reappear on heating the solution; this
reaction is also given by other poly-hydroxy aleohols, such as
mannite or glucose,
Add a few drops of the fluid suspected to contain the gly-
cerin toa small quantity of powdered borax ; stir well together ;
dip the looped end of a platinum wire into the mixture, and
heat in the Bunsen flame; a deep green color is produced
(Senier and Lowe).
The glycerin liberates boric acid, which colors the flame (see p.
320), Ammonium salts, which similarly affect borax, must first
be got rid of by boiling with solution of sodium carbonate. Acids
must be neutralized. Liquids containing much indefinite organic
matter must sometimes be evaporated to dryness, the residue
extracted with alcohol, and the alcoholic extract tested for glycerin,
To detect traces, liquids must be concentrated,
Glycerin, by action of concentrated nitric acid, yields ¢rinifrine,
nilroglycerin, or glyceryl nitrate, C A(NO,),. Itis highly explosive,
a very small quantity being liable to explode during preparation,
and with great violence. 75 parts of nitroglycerin absorbed b
25 of porous silica, yield a pasty mass, more convenient to handle
than nitroglycerin itself, which is used for blasting, under the
name of dynamite. A one percent. solution of nitroglycerin in aleo-
hol is the Spiritus Glycerylia Natratis, U. 8. P.
Besides glycerin itself, there are several official preparations of
glycerin—solutions of phenol and tannic acid and of borax in gly-
cerin, and also a species of mucilage of starch in glycerin—Glyeeri-
tum Acidi Tannici, Glyceritum Amyli, Glyceritum Boroglycerini,
Glyceritum Ferri, Quinine: et Strychnine Phosphatum, Glyeceritum
FTydrastis, and Glyceritum Phenolia,
Fats and Oils.
Processes of Extraction. —Fixed oils and fats are extracted from
animal and vegetable substances by pressure or straining, with or
without the aid of heat, or by digestion in solvents, as ether, ete.,
and evaporation of the solvent,
FATS AND OILS.
Constitutionand General Relations.—F ixed oils and fats are ether-
eal salts or esters, and the metallic salts (soaps), obtained from them
by the action of metallic hydroxides (by saponification), are quite
‘comparable with the salts of other organic acids. Just as potas-
sium acetate, KC,H,O,, is a compound of potassium (K) with the
acid radical of the acetates, (C,H O,), so soft soap is a compound
of potassium with the acid radical! of the oleates (C\.H..O,), and
hence is chemically termed potassium oleate, KC HO. Olive
oil (Oleum Olive, U.S. P.), from which soap is officially prepared,
is mainly oleate of the trivalent radical géyeery/, (C,H,) ; the form-
ula“of this oleate is C,H,(C,,H,.O,),, and its name o/eine, The for-
mation of a soap, therefore, on bringing together oil and a moist
oxide or hydroxide, is an ordinary case of double decomposition,
as seen already in connection with lead plaster (p, 224), or as illus-
trated in the following equation representing the formation of com-
mon hard soap :—
sNaOH + C.H,(C,.H,.0,), = 3NaC,H,O C.H.(OH)
Sodium iyersHPoidatet* Sodium oleate’ > &} . 's
hydroxide (vegetable oil) (hard soap) dro ide
h
(caustic soda) (glycerin)
Berthelot has succeeded in preparing oil artificially from hydro-
gen oleate, or oleic acid, HC,,H,O,, and glycerin ; and it is said to
be identical with the pure oleine of olive oil and of other fixed oils.
Olive oil is liable to contain cotton-seed oil, itself a good oil, but
cheaper than olive oil ; it may be detected by Becchi’s test. The
following are the official directions for carrying out the test ;—If
5 Ce. of the oil be shaken with 5 Ce, of a reagent prepared by dia-
solving 0.1 gramme of silver nitrate in 10 Ce. of alcohol, with the
addition of two drops of nitrie acid, no dark color should be pro-
duced when the mixture is heated on a water-bath for five min-
ules.
Hard fats consist chiefly of sfearine—that is, of glycery] tristear-
ate, C,H,(C,,H,.0,),. Mr. Wilson, of Price’s Candle Company,
obtained stearic and oleic acids and glycerin by simply passing
steam, heated to 500° or 600° F_ (260° or $15.5° C.), through
melted fat. Both the glycerin and the fat-acids distil over in the
current of steam, the glycerin dissolving in the condensed water,
the fut-acids floating on the aqueous liquid. From glyceryl ole-
ate and steam there result hydrogen oleate (oleic acid) and glyceryl!
hydroxide (glycerin).' The oleic acid (Acidum Oleiewm, U.S. P.)
is separated by cooling and pressing the mixture, It is a straw-
colored liquid, nearly odorless and tasteless, and with not more
' Any such decomposition of water and fixation of itselements, whether
direct as above, or indirect through the intermediate agency of ayponifica-
tion, is termed hydrolyris (iSep, hudwr, water, Abw, luo, 1 decompose), The
fixation of water without such actual separation of its elements from cach
other is termed hydration,
440 ORGANIC CHEMISTRY.
than a faint acid reaction, Unduly exposed to air, it becomes brown
and decidedly acid, Sp. gr. 0.890 to 0.910. It is insoluble in
water, but readily soluble in alcohol, chloroform, and ether. At
40° to 41° F. (4.5° to 5° C.), it becomes semi-solid, melting again’
at 56° to 60° F. (18,3° to 15.5° C.), It should be completely saponi-
fied when warmed with potassium carbonate; and an aqueous
solution of the resulting salt, neutralized by means of acetic acid
and treated with lead acetate, should yield a precipitate which,
after washing with boiling water, is almost entirely soluble in ether,
showing the absence of any important quantity of stearic and pal-
mitic acids, lead stearate and palmitate being insoluble in ether.
In a mixture of oils or fats and free fatty acids, the latter may
be determined by taking advantage of their solubility in alcohol,
and the formation ofa neutral soap on shaking the alcoholic solu-
tion with sodium hydroxide, phenol-phthalein being used as indi-
cator, (See the section on the use of standard sodium hydroxide
solution in volumetric analysis, )
The author found, Pharmaceutical Journal, March, 1863, that
oleic acid readily combines with alkaloids and most of the metallic
oxides or hydroxides forming odeafes which are soluble in fats, In
this way active medicines may be administered internally in con-
junction with oils, or externally in the form of ointments. O/e-
alum Atropine, U.S. P., Oleatum Cocaine, U, 8. P., Oleatum
Veratrine, U.S. P., Unguentum Hydrargyri, U. 8. < Tichborne
considers the formula of mercuric oleate to be Hey(C,.H,.0,),, H,O.
Some fats, such as ‘ suint’’ from sheep’s wool, and e unctuous
mutter from bristles, feathers, horn, and hair generally, yield by
saponification, ete. , fatty acids and, ‘instend of glycerin, choleaterin,
C,,H,,OH, a crystal ine monatomic alcohol, The “lanoline” of
pharmacy y is cholesterin fat which has absorbed a large volume of
witer,
Wool Fat (Adeps Lane, U. 8. P.) is the purified cholesterin-
fat of sheep’s wool. It is a yellowish, tenacious, unctuous mass ;
almost inodorous } melting-point about 104° F. (40° C.) ; readily
soluble in ether or in chloroform, sparingly soluble in aleohol. 1
gramme should dissolve almost completely in 75 cubic centimetres
of boiling alcohol, the greater part separating: in flocks on cooling,
When incinerated. with free access of air, it leaves not more than
0.3 percent. of ash, which should not be alkaline to litmus, 2
grammes dissolved in 10 Ce. of ether, two drops of phenol-phtha-
lein T. &., being added, should with one drop of normal potas-
sium hydroxide v.8., , produc e a deey “p red color (limit of acidity).
[ts solution in c hloroform poured j gently ove r the surface of sul-
phuric acid acquires a purple- red color, ‘He: ated with potassium
hydroxide T. S., no ammoniacal odor should be evolved (absence
of organic nitrogenous mutte r).
Hydrous Wool Fat (. fe lepn Lane Hydrosus, U. 8, P.) is an inti-
mate mixture of 7 parts of w ‘ool fat with 8 of water. Tt is com-
SOAPS.
monly known as ‘‘ Lanoline.'’ It is yellowish white ; free from
rancid odor, When heated it separates into an upper oily, and a
lower aqueous, layer. 10 grammes heated on a water-bath, witli
stirring, until the weight is constant, should yield not less than
7 grammes of residue, which should answer to the tests for Adeps
Lane,
Soaps.
Linseed oil boiled with solution of potassium hydroxide yields
potassium soap, or soft soap (Sapo Mollis, U. 8. P.) ; with sodium
hydroxide, sodium soap, or hard soap (Sapo, U. 8, P. is prepared
from sodium hydroxide and ofive oil), or white Castile soap, as dis-
tinguished from the variety of hard Castile, or Marseilles soap,
which is ‘‘mottled” by iron soup; mixed with lime-water, calcium
soup Linimentum Caleia, U. 5. P.), while an ammonium soap, (Lini-
mentum ammonve, U. 5. P.), may be made by mixing ammonia
water, alcohol, cotton-seed oil and oleic acids,—all containing
oleates, chiefly, of the respective metallic radicals, Their mode
of formation is indicated in the equation on p, 439, The alkali-
metal soaps are solublein alcohol, the others insoluble. Linimen-
tum Saponis and Linimentum Saponis Mollis are official. A green
soap, much used on the continent of Europe, and, indeed, official
in Germany (formerly as Sapo Viridis, now as Sapo Kalinus
Venalis), is made by adding indigo to ordinary soft soap; the
yellow color of the soap yielding with the indigo a greenish com-
pound, Curd Soap is a soap made with sodium hydroxide and a
purified animal fat consisting principally of stearin. It will, of
course, chiefly contain sodium stearate. In pharmacy it is often
advantageously employed instead of the ‘‘ hard soap.’’
The hard soap met with in commerce is made from all varieties
of oil, the commoner kinds being simply the product of the evapo-
rated mixture of oil and sodium hydroxide, while the better sorts
have been separated from alkaline impurities and from the glycerin
produced on boiling the oil with sodium hydroxide lye, by the addi-
tion of common salt, or of excess of lye, to the liquors, which causes
the precipitation of the pure soap asacurd. Potassium soap is not
80 readily precipitable by salt; moreover, some sodium soap results,
Saponification on the small scale is much facilitated by first well
mixing the oil with 5 percent. of sulphuric acid, and letting this
mixture stand for twenty-four hours. The dark product is then
readily soluble when boiled with sodium hydroxide, and the clear
liquid yields a crust of white soap on cooling. «If required quite free
from alkali, the resulting soap is boiled with water until dissolved,
salt is added, and the whole cooled. A cake of pure soap results.
The cleansing action of soap ia really the cleansing action of a
dilute solution of alkali, a small quantity of soap interacting with
a large quantity of water to form acid stearates and palmitates,
44? ORGANIC CHEMISTRY.
and even acid oleates after a time, which separate from the solution,
and free alkali, which remains in solution.
Yellow soap is a common, cheap soap, containing a good deal
of resin soap, resin consisting chiefly of acids—pinic, sylvie,
pimaric, ete.—which readily interact with alkalies to form true
soaps.
Saponification.—This term is now extended in chemistry so as
to include any process analogous to the foregoing—any reaction
in which an alkali decomposes an ethereal salt or alky! salt (ester),
Solid Fats.
1. Lard ( Adeps, U, 5. P.) is the purified internal fat of the
abdomen of the hog—the perfectly fresh omentum or flare, freely
exposed to the air to dissipate animal odor, rubbed to break up
the membranous vesicles, melted at about 130° F, (54.4° C.), and
filtered through paper or flannel. 2. Benzoinated Lard ( Adepa
Benzoinatusa, U. 8. P.) is lard heated over a water-bath with ben-
zoin (fifty parts to one), which communicates an agreeable odor
and prevents or retards rancidity. Purified lard is a mixture of
oleine and stearine. Margarine, formerly supposed to be a con-
stituent of lard and other soft fats, is now regarded as a mere
mixture of palmitine (the chief fat of palm-oil) and stenrine,
3. Suef, the internal fat of the abdomen of the sheep, purified by
melting and straining, forms the official Prepared Suet ( Serum
Preparatum, U. 8. P.); it is almost exclusively composed of
stearine, or glyceryl stearate, C\H.(C,,H,.O,),. Tollow is chiefly
mutton-fat and beef-fat, but may contain other animal fats; some
vegetable fats also are termed tallow. 4, Expressed oil of Wud-
meg, commonly but erroneously termed Oi/ of Mace, is a mixture
of a little volatile oil with much yellow and white fat; the latter
is myristin or glyceryl myristate, C,H,(C,,H,,0,),. 5. Oilof Theo-
broma, or Cacao butter (Oleum Theobromatis, U. 8. P.), chiefly
stearine, but with one higher and some lower homologues (Heintz),
is a solid fat pressed from cocoa nibs the roasted and broken see
of the Theobroma Cacao, The seeds contain from one-half to two-
thirds of this fat. [Cocoa is too rich for use as food, hence it is
diluted with farina (affording ‘‘ cheap cocoa’’) or sugar (affording
chocolate) or has a portion of its fat extracted, while its solublity
is, in certain brands, usefully increased by a process which results
in a slight addition to the potassium salts of its ash, chiefly to the
potassium phosphate.] 6. Chcoanut oil or butter, a soft fat con-
tained in the edible portion of the nut of Cocos nucifera, or cocoa-
nut of the shops, is a mixture containing glyceryl compounds of
six acid radicals—namely, those of caproic (C,H,,O,), caprylic
(CH,,0,), rutic (C,,H,,0,), laurie (C,,H,,0,), myristie (C,, O,),
and palmitic (C, H,,O,) acids—which, like some acid radicals fr
resin, when united with sodium, form a soap differing from ordi-
FIXED OILS, 443
nary hard soap (sodium oleate) by being tolerably soluble in-a
solution of sodium chloride; hence the use of cocoanut oil and
resin in making marine soap, a soap which for the reason just
indicated, readily yields a lather in sea-water, 7. Kokum Butter,
Garcinia Oil, or Concrete Oil of Mangosteen, a whitish or yellow-
ish-white fat obtained from the seeds of Garcinia Indica or G.
purpurea, is composed of stearine, myristicine and oleine. It is
recognized in the old Pharmacopaia of India (Garcinia purpuree
Oleum),
Dubie commonly yields 874 percent. of insoluble fat acids on
saponification and decomposition of the soap by acid, Other ani-
mal fats, with which butter is likely to be adulterated, yield about
953. Hence the percentage of fat acids, and, especially, volatile
acids, insoluble acids, and soluble acids, yielded by a suspected
sample of butter, indicates purity or the opposite. Occasionally,
however, a sample of genuine butter may not conform to the fig-
ures, hence they cannot be relied on to show the exact extent of
sophistication.
Fixed Oils,
Fixed and Volatile oils are naturally distinguished by their
behavior when heated; they also differ in their chemical nature, a
fixed oil being, as already stated, an ethereal salt, while a volatile
oil is usually a hydrocarbon of some kind, mixed with a compara-
tively small proportion of a substance—containing oxygen as well
as carbon and hydrogen—to which the odor of the oil is largely
due, Substances of the latter kind are now articles of trade under
the name of ‘‘ concentrated essential oils.’’
Drying and Non-drying Oils,— Among fixed oils, most of which
are glyceryl oleate with a little palmitate and stearate, a few such
as—l. Linseed oil (Oleum Lini, U.S. P., contained in Linum,
U. 5. P., which when reduced to a coarse powder, is ground lin-
seed), and 2, Cod-liver oil (Oleum Morrhum, U. 8. P.), and, to
some extent, caxfor and crofon oils, are known as drying oils, from
the readiness with which they absorb oxygen and become hardened
toaresin. Linseed commonly contains 37 or 38 percent. of oil ;
25 to 27 percent. is obtained by submitting the ground seeds to
hydraulic pressure, 10 to 12 percent. remaining in the residual oi/-
cake, Boiled oil is linseed oil which has been boiled with lead
oxide. This treatment increases the already great tendency of lin-
seed oil to resinify, forming /inoxryn on exposure to air. The dry-
ing oils appear to contain linoleine, an oily substance distinct from
oleine, Cod-liver oil contains an unimportant trace of iodine, 1
in one or two million parts, according to Stanford ; a little choline
is found also, and other bases, Gautier and Mourgues having iso-
lated aselline, C,H.N,, and morrhuine, C,H).N,, besides butyl-,
amyl-, and hexyl-umines and dihydro-lutidine, Among the non-
444 ORGANIC CHEMISTRY,
drying oils are the following :—3. Almond oil (Oleum Amygdale
Expressum, U.S. P.), yielded both by the bitter (Amygdala Amara,
U.S. P.) and the sweet seed (Amygdala Duleis, U. 5. P.), to the
extent of 45 and 50 percent, respectively. 4. Lycopodium (Lyeo-
podium, U, 8. P.), a yellow powder composed of the spores of the
common Club-Moss (Lycopodium clavatum), contains a large pro-
portion of a very fluid fixed oil ; also an alkaloid (Bédeker), /yeo-
podine, C,H,N,O,. 5. Oil of male sern (Aspidium, U.S. P.), a
vermifuge obtained by exhausting the rhizome with ether and
removing the ether by evaporation—a dark-colored oi! containing
a little volatile oil and resin, Its active constituent appears to be
filmaron, C,.H,,O,,, & bright yellowish-brown powder, insoluble or
sparingly soluble in water and alcohol, but easily soluble in ether,
acetone, etc. By certain decompositions filmaron yields filicie acid,
C,,H,,0,. The extract also contains flavaspidic acid, aspidinol,
and other substances, 6. Fixed oil of mustard, a bland, inodor-
ous, yellow or «mber oil, yielding by saponification and action of
sulphuric acid, glycerin, oleic acid, and erucie acid, HCHO,
(Darby), 7. Araehia oil is found to the extent of 40 or 50 percent,
in the seeds of the Arachis hypogaea, the Pea-nut, Ground-nut, or
Earth-nut (so-called because the pod of the herb by the growth of
its stalk downward if forced beneath the surface of the ground and
there ripens), Itis chiefly oleine, but contains hypogewine, palm-
itine, and arachine. The oil is largely used in India in place of
olive oil, and is becoming much employed in Europe, especially
for soap-making, 8, Olive oil (Oleum Olive, U. 8, P.), already
noticed, 9. Shark-liver oil from Squalus carcharias, is used as a
substitute for cod-liver oil in India, 10. Crofon oil (Oleum Tiglti,
U. 8. P.). Geuther states that no such acid as crotonic is obtain-
able from croton oil, but acetic, butyric, valeric, and higher mem-
bers of the oleic series, together with figlic acid, HC,H,O, HH.
Senier states that alcohol separates croton oil intoa soluble oil con-
taining the powerful vesicating principle of croton oil and an Insolu-
ble non-vesicating but powerfully purgative principle. Kobert
states that free crotonoleic acid is both the vesicant and the purga-
tive. 11, Sesamé oil (Gingelly, Teal, or Benne Oil) from the seeds
of Seaamum indicum, is also largely used in Europe. It has most
of the characters of the best olive oil. It may be detected in olive
oil by well shaking the sample with a solution of pyrogallol in con-
centrated hydrochloric acid, and separating and boiling the acid
liquid, a purplish color resulting if sesamé oil be present. 12,
Gynocardia oil or chaulmoogra oil, from the seeds of Gynocardia
odorata (Chaulmugra), Tt consists of gynocardic, palmitic, h
geic, and cocinic glycerides, with some gynocardic and palmitic
acids (Moss), 13, Castor oil (Oleum Ricini, U. 8. P.) is chiefly
glyceryl ricinoleate, CA(C,.H..0,),, or ricinoleine, a slightly oxi-
dized oleine, soluble, unlike most fixed oils, in alcohol and in
glacial acetic acid, Castor-oil seeds were stated, by Tuson, to con-
MANNITE. 445
tain an alkaloid, ricinine, to which Beck gave the formula,
C,,H,,N,O, Soave holds that ricinine is not an alkaloid and that
its formula is C,\.H,.N,O,. It possesses no purgative property,
Castor-oil seeds also contain an albumose, ricin, resembling,
physiologically, but not quite chemically, the abrin, of jequirity.
Trihydrie Alcohols, of the C,H, (OH), series.
Pyrogattol or Pyrogallie acid. —T rihydroxybenzene, C,H(OH),,
(Pyregallol, U.S. P.). (See p. 343),
Polyhydric Aleohols,—Erythrite or Lichen Sugar, C,H,(O8),,
found in Protococeus vulgaris, Roccella tinctoria, and R. fuciformia,
is one of the few known fetrahydric alcohols. Quereite, the sugar
of acorns, is penfahydric ; Mannite is hevahydrie. Sorbite, which
is also hexahydric, occurs in the fruits of the order Rosacer,
Mannite, (,H,(OH),.—Boil manna ‘with 15 or 16 parts of
alcohol, filter, and set aside; mannite separates in colorless
shining crystals or acicular masses, to the extent of from 60 to
50 percent. of the manna. It is closely related to the ordinary
sugars, fructose (levyulose) yielding mannite by the action of
nascent hydrogen (sodium amalgam ) :—
CH..O 2e =— H,O
Fructose’ ieee Mannite™
Mannite or mannifol does not undergo fermentation in contact
with yeast. With nitric acid it forms explosive nitromanni(e,
OH, (NO,),. . *
Manna is a concrete saccharine exudation obtained by making
transverse incisions in the stems of cultivated trees of Frarinus
Ornus. It occurs in stalactitic pieces, varying in length and thick-
ness, flattened or somewhat concave and of a pale yellowish-brown
color on their inner surface, and nearly white externally. This
manna, which is known as flake manna, is crisp, brittle, porous,
crystalline in structure, and readily soluble in about six parts of
water, Odor faint, resembling honey ; taste sweet and honey-like,
combined with a slight acridity and bitterness, It contains about
10 percent. of moisture, Mannite is also met with in celery, onions,
asparagus, certain fungi and sea-weeds ; it occurs in the exudations
of apple-trees and pear-trees, and is produced during the viscous
fermentation of sugar. When oxidized, it yields first the sugur
termed mannose, CH,OH(CHOH),COH, then some mannonic acid,
CH,OH(CHOH),COOH, and finally saceharie acid, (CHOH),-
(COOH),.
446 ORGANIC CHEMISTRY.
Duleite, isomeric with mannite, is formed by the action of sodium
amalgam on galactose (from milk sugar). It differs from mannit
by yielding mucic acid, (CHOH) (COOH),, isomeric with saccharic
acid, when oxidized with nitric acid,
QUESTIONS AND EXERCISES,
Describe the process for the preparation of ether, giving equations. —
How is commercial ether purified ?—How is phenol artificially and com-
mercially prepared }—How would you distinguish phenol from creosote?
—Give the formule and systematic names for picric acid, sodium ear-
bolate, and resorcino!.—Give names for the substances having the formule
CeHyOH.CHs and CoHsCH,OH.—What are glycols and how are they pre-
pared (—Give formula and wention the chief properties of gycerin.—
What is the specific gravity of glycerin?—By what tests is glycerin
recognized 7—Enumerate some official preparations in which glycerin is
employed.—Give a sketch of the general chemistry of fixed oils, fats and
soaps.— What is the difference between hard and soft soap?—Which soaps
are official ?—Name the source of lard. How is “‘Adeps, U. 5. P.,”’ obtained ?
—Mention the chief constituents of suet.—Whenee is ecacao-butter
obtained ?—Why is marine soap so-called, and from what fatty matter is
it almost exclusively prepared !—What do you understand by drying and
non-drying oils ?—In what respect. does castor oil differ from other oils ?—
Classify pyrogallol (Pyregallic acid), erythrite, mannite, and dulcite.—
Describe the source and characters of manna,
ALDEHYDES AND ACIDS.
Aldehydes and acids may be formed by the oxidation of the
primary alcohols, glycols, etc. Monohydric alcohols, having
only one hydroxyl (OH) group, form monobasic acids, dihydrie
alcohols (glycols) having two hydroxyl groups, yield monobasic
and dibasic acids; and so on, Thus:—
CH,CH,OH ) .., { CH,COH ) _,(CH,COOH
Ethyl alcohol { Yields | Acetaldehyde | and | Acetic acid
CH,OH
yields CH,OH (
j
| COOH
and
| A
CH,OH ~ cOH f[
Glycolaldehyde J
| Glycollic acid
CH,OH a
Glycol and COH
: COOH
or alec
Ethylene glycol also and
)
boo
Oxalic acid
COH a
Oxalaldehyde
or Glyoxal
Tt will be seen that the groups CO Hand COOH denote reapectively
an aldehyde and an acid, the H in the COOH group being replace-
able by a metal, as in the case of CH,,CO.ONa (sodium acetate),
ALDEHYDES AND ACIDS. 4A7
Acids may also be obtained by acting on the nifri/es! (or cyan-
ides of the hydrocarbon radicals, with hydrochloric acid and
water. Thus:—
CH,CN + 2H,O + HCl = CH,COOH + HN CI
Acetonitrile Water Hydrochloric Acetic acid Ammonium
acid chloride
Many aldehydes and acids occur in nature; for example, oil of
meadow-sweet (salicylaldehyde), oil of bitter almonds (benzalde-
hyde), tartaric acid, citric acid, ete.
General Reactions.—Aldehydes form crystalline compounds
with acid potassium sulphite; by oxidation they yield acids, and
by the reducing action of nascent hydrogen they yield alcohols;
while acids yield aldehydes and then alcohols by reduction with
nascent hydrogen, With oxides, hydroxides, carbonates, and
sometimes with metals, acids form metallic derivatives (salts). With
the alcohols, acids yield alkyl? or ethereal salts, as, for instance,
acetic ether, By the action of the chloride, iodide, or bromide
of phosphorus their hydroxyl group is replaced by chlorine,
iodine, or bromine:—
8CH,COOH + PC] = 30H,CO.Cl + POH,
Acetic Phosphorus Acetyl Phosphorus
acid trichloride chloride acid
Like inorganic acids, they form anhydrides by the elimination of
water: —
) _ CHOCO
2CH,COOH — H,0 = GH60 O
Acetic acid Water Acetic anhydride
The important aldehydes and acids will now be mentioned,
1 The nitriles may be prepared by the interaction of the halogen deriva-
tives of the hydrocarbons with potassium cyanide — ;
CH;xCl + KCN = CH;sCN + #£&KCi
Methy Potassium Methyleyanide Potassium
chloride eyanide oracetonitrile chloride
The reactions of nitriles indicate that the hydrocarbon radical is united
tothe carbon of the cyanogen group. In the isomeric substances called
inonitriles or carbamines (obtained by the interaction of the halogen deriva-
tives of the hydrocarbons with silver cyanide) the hydrocarbon radical
appears to be united to the nitrogen of the cyanogen group.
Alkyl Salts, Alkyl, from the Arabic article al,the, as in alkali, alcohol,
etc., and the termination common to the names of such radicals as ethyl,
amyl,and phenyl, and as scen in methyl, the prototype of such names,
In Germany the word ester (see p. 401), a mere variation of the word ether,
is timilarly employed. In the scientific chemistry of both countries it is
thus songht to restrict the name ethers to the organic radical oxides, as
common ether, (CyHy)eO (Ether, U.S. P.).
448 : ORGANIC CHEMISTRY,
The Acetic Series of Monobasie Acids,C,H,,,,CO.OH.
These acids are formed by the two general methods given,
namely, from primary alcohols of the ethyl series and from eyan-
ides of the paraffin hydrocarbon radicals,
Formie Acid, H.COOH, See p. 824.
Formaldehyde, H.COH, is obtained by passing a mixture of
methyl alcohol vapor and air over a heated spiral of metallic copper.
Atordinary temperatures it is a gas which dissolves readily in water,
An aqueous solution of formaldehyde, commercially known as
‘*formalin,’’ is largely used as an antiseptic and disinfectant.
This Solution of Formaldehyde (Liguor Formaldehydi, U, 8, P.),
contains about 40 percent. of formaldehyde, HCOH, and is a
liquid of suffocating odor. When evaporated over sulphuric acid,
a polymeride, C,H,O,, paraformaldehyde, is formed; and when
allowed to remain in contact with lime-water, another polymeride,
O,H,,0,, formose, is produced, which is a mixture of sugars. This
polymerization of an aldehyde is of interest as suggesting methods
for preparing sugars by synthesis.
By the action of ammonia on formaldehyde, hexamethylenamine
or hexamethylene-tetramine, (CH,).N, (Heramethylenamina,
U. 8. P.) is obtained.
Acetic Acid, CHJCOOH (Methyl-formic acid), Obtained by
oxidizing ethyl alcohol and in other ways, See p. 281.
Aldehyde, or Acetaldehyde, C,H,O, or CH,COH,
Experiment.—Place together, in a capacious test-tube (or
flask ), about four parts of potassium dichromate and twelve
of water; cautiously mix four parts of alcohol with five of
concentrated sulphurie acid, and allow the mixture to flow
slowly through a stopeock funnel on to the contents of the
tube, and gently warm the mixture; aldehyde (a/eohol
dehydrogenatum), a highly volatile liquid, is immediately
formed, and its vapor evolved, recognizable by its peculiar,
somewhat fragrant odor. Adapt a cork and rather long
bent tube to the test-tube, and let some of the aldehyde
slowly distil over into another test-tube, the condensing-tube
being kept as cool as possible, Set the distillate aside for a
day or two; the aldehyde will have nearly all disappeared,
and acetic acid he found in the tube. Test the remaining
liquid by means of litmus-paper ; it will be found to haye an
acid reaction; make it slightly alkaline by adding a drop or
two of solution of sodium carbonate, then boil to remove ‘any
aleohol and aldehyde present, add sulphurie acid, and notice
the characteristic odor of the acetic acid evolved,
These experiments will render the process of oxidation de-
scribed in connection with acetic acid more easily understood,
ALDEHYDES AND ACIDS. 449
Pure diluted alcohol is not oxidized by exposure to air alone ; but
in presence of the ferment, Mycoderma aceti, it is oxidized first to
aldehyde and then to acetic acid.
In the above process the potassium dichromate and sulphuric
acid furnish nascent oxygen, which then acts on the alcohol ( just
as in presence of the ferment mentioned above, the oxygen of the
air acts on the alcohol in fermented infusion of malt, and in beer
or wine), giving aldehyde :—
8CH,CH,OH + K,Cr,0, + 4H,SO
Alcoho .
= 3CH,COH + K,SO, + Cr,(S80,), + 7H,O
Aldehyde
The aldehyde rapidly, even when pure (more rapidly when impure),
absorbs oxygen and yields acetic acid :—
2CH.COH + O, = 2CH,COOH
Aldehyde Oxygen Acetic acid
The aldehyde from the above reaction may be mixed with twice
its yolume of ether, placed in a bottle surrounded by ice, and
saturated with dry ammonia; a crystalline compound, al/dehyde-
ammonia, CH,,CH.OH.NH,, separates. Pure aldehyde may be
obtained from this by distilling with dilute sulphuric acid,
Teats.—A dehyde heated with solution of potassium hydrox-
ide gives a brownish-yellow resinous mass of peculiar odor.
Its aqueous solution reduces silver salts, giving a mirror-like
couting to the inside of a test-tube, When acted on by phenol
dissolved in sulphuric acid, it gives a red color. Aldehyde
on keeping, or in contact with sulphurie acid, zine chloride,
ete., yields two polymerides—metaldehyde, xC,H,O, and
paraldehyde, C.H,.O,, the latter having a characteristic odor.
Paraldehyde (Paraldehydum, U. S. P.) boils at 253.4° to
257°F. (125° to 125°C.), dissolves in water, alcohol, or ether, is
neutral, and should not become colored on standing for two
hours with solution of potassium hydroxide (absence of alde-
hyde), It may he congealed to a clear crystalline mass which
melts at 51° F. (10.5° C.),
Chloral.
Chioral, or triehlaraldehyde, CC\,COH, is a chlorine substitu-
tion derivative of aldehyde, although it cannot directly be obtained
by acting on aldehyde with chlorine, because condensation pro-
ducts are formed.
Experiment,—Pass a rapid current of dry chlorine into
pure absolute alcohol so long as absorption occurs, During
pa
450 ORGANIC CHEMISTRY,
the first hour or two the alcohol must be kept cool, and after-
ward gradually warmed till ultimately the boiling-point is
reached. The crude product is mixed with three times its
volume of sulphuric acid and distilled, again mixed with a
similar quantity of sulphuric acid and again distilled, and
finally rectified from quicklime.
In the formation of chloral it would seem that the substances
first formed are hydrochloric acid and aldehyde, the latter of
which instantly combines with alcohol to form acetal:—
CH,CH,OH + Cl, = CH,COH 4- 2HCl
Alcohol Chlorine Aldehyde Hydrochloric acid
CH,COH + 2C,H.0H = CH,.CH.(0C,H,), + HO
Aldehyde Alcohol Acetal Water
Acetal' by further chlorination yields trichloracetal:—
CH;.CH(OC,H,), + 8Cl, = CCl,CH.(OC,H,), + 3HCl
Acetal ( ‘hlorine Trichloracetal - Bydneneee
ac
Trichloracetal when acted on by the hydrochloric acid yields
ethyl chloride and chloral aleoholate:—
ccl,cH<0C 7 + HO! = ccl,cH<@G4s +0801
Trichlorace 1a Chioral alcoholate Ethy! chloride
From the alcoholate, (richlor-aldehyde or chloral is liberated by
treatment with sulphuric acid:—
CC1,.CH, (OC,H,)OH+ H,SO, = CCl.COH- C,H, H80,4-H,0,
Chioral aleoholate Sulphurle Chioral vent h drogen Water’
acid sulpbate
Properties. —Chiloral is a colorless liquid, of oily consistence.
Sp. gr. 1.502. Boiling-point 201.2° F. (94°C). Its vapor has
a penetrating smell, and is somewhat irritating to the eyes, When
mixed with water, heat ia disengaged, and solid, white, erystalli-
gable, hydrated ‘chloral OCLC H(OH), (Chloralum hydratum,
U.S. P.), also called C ‘hloral Hydrate, results, ‘* Hydrated
Chloral”’ is a true glycol, is systematic name being trichlorethyl-
idene glycol:—
CH (OH), CC) ,CH(OH),
Ethyle ne glye “ol Trichlorethylidene glye ol
Hydrated chloral fuses easily when heated, solidifies at about
120° F. (48.9° C.), boils at from 202° to 206° F, (944° to
1 Methylal.—C2( OCH): the lowest member of the series, is oceasion-
ally used as a soporific,
CHLORAL HYDRATE.
96.7° C.). It sublimes as a white crystalline powder. Both
chloral and hydrated chloral are soluble in water, aleohol, ether,
chloroform and oils. Oils and fats are also soluble in hydrated
chloral, The aqueous solution should be neutral, and should give
no reaction with silver nitrate. Chloral, especially if it contains
a trace of acid, may undergo a spontaneous change into an opaque
white isomeric modification, mefach/oral, insoluble in water,
alcohol, or ether, but convertible by prolonged contact with water,
or by distillation, into the ordinary condition. By action of
dilute alkalies chloral yields alkali-metal formate and chloro-
form:—
CCLCOH + KOH = H.CO.OK + CHCl,
Chloral, or rather concentrated aqueous solution of hydrated
chloral (3 in 4), injected beneath the skin yields chloroform,
and produces narcotic effects (Liebreich, Personne), Chloroform
itself admits of similar hypodermic use (Richardson), If admin-
istered by the stomach, thirty to eighty grains of solid hydrated
chloral are required. The final products of the reaction of the
chloroform and blood are sodium formate and chloride. A con-
centrated alcoholic solution of potassium hydroxide effects an
analogous change:—CHCl, + 4KOH = H.COOK + 8KCl +
2H O,
By the oxidizing action of nitric acid, hydrated chloral is con-
verted into trichloracetic acid, CCI,COOH, (Acidum Trichlor-
aceticum, U. 8. P.), a white crystalline solid. Ammonia water
and moist calcium hydroxide, as well as weak solutions of
fixed alkalies, hydrated chloral into a metallic formate and chloro-
form. The reaction with the slaked lime being especially definite
and complete (Wood), it may be employed in ascertaining the
quantity of hydrated chloral in a sample of the commercial article,
2C0C],CH(OH), + Ca(OH), = 2CHCI, + (HCOO),Ca + 2H,0
ee . :
= te
2 164,12 2118.45
From the foregoing equation and molecular weights, it is
obvious that 100 grains of hydrated chloral, if quite dry, will
yield by distillation with 30 grains of slaked lime and an
ounce of distilled water (in a small flask with a long bent
tube kept cool by moistened paper), 72.17 grains of chloro-
form by weight or (the sp. gr. of chloroform being taken at
1.493), about 52 minims.
Small quantities of hydrated chloral in dilute solutions may be
determined by converting its chlorine into a soluble chloride by
treatment with zine and acetic acid, and titrating with volumetric
452 ORGANIC CHEMISTRY.
svlution of silver nitrate (Short). A quantity of solution con-
taining not more than 0.05 gramme is placed in a small flask with
granulated zine and acetic acid, and allowed to stand twenty-four
hours; the solution is then poured off and the zinc washed two or
three times with distilled water, a little potassium chromate added.
It is then titrated with tenth-normal silver nitrate solution in the
usual way, the acetic acid and zine acetate not interfering with
the indications. 1000 Ce. of the silver solution indicate 5,47 of
hydrated chloral.
Pure Hydrated Chloral.—Liebreich, who first proposed the use
of hydrated chloral, gives the following as the characteristics of
the pure article: —Colorless, transparent crystals, Does not decom-
pose by the action of the atmosphere, does not leave oily spots
when pressed between blotting-paper, affects neither cork nor paper.
Smells agreeably aromatic, but a little pungent when heated.
Tustes bitter, astringent, slightly caustic. Seems to melt on rub-
bing between the fingers. Dissolves in water like candy without
first forming oily drops; and the solution is neutral or faintly acid
to test-paper. Dissolves in carbon bisulphide, petroleum, ether,
water, aleohol, oil of turpentine, ete. Its solution in chloroform
gives no color when shaken with sulphuric acid. Boiling-point
203° to 205° F. (95° to 96.1° C.). It volatilizes without residue,
Distilled with sulphuric acid, the chloral should pass over at 205°
to 207° F. (96.1° to 97.2° C.). It melts at 133° to 136° FP. (66°
to 57.7° C.), again solidifying at about 120° F, (48.8°C,). Gives
no chlorine reaction on treating the solution in water (acidulated
with nitric acid) with silver nitrate.
Impure Hydrated Chloral.— Yellowish, cloudy, Decomposes;
leaves spots when pressed between blotting-paper; attacks corks
and the paper of the packing. Has a pungent and irritating
smell; on opening the bottle is sticky and often emits fumes.
Taste strongly caustic, With water forms oily drops or is partially
insoluble. Boils at a higher temperature. On treatment with
sulphuric acid it turns brown, with liberation of hydrochloric
acid. Gives chloride reaction on treating the solution in water
eee with nitric acid) with silver nitrate.
Chloralformamide, (Chioralformamidum, U, 8. P.), CCILOHOH,
NH.COH, is a crystalline solid produced by the direct union of
anhydrous chloral and formamide,
Chioralose, C,H,,Cl, Og, is a derivative of chloral, prepared by
heating together anhy drous chloral and glucose, then extracting
with ether, and repeatedly distilling with water.
Chioral aleoholates are— obtained | on combining aleohols with
chloral, Chloral alcoho late or trichlorethylidene ethyl ether,
COC)LCH< ori is obtained ‘by salting sloobet with chloral, it
is in fact " hydrated « ‘hloral ’ with one hydroxyl! group replaced
by ( oc. H,).
BROMAL; BUTYL CHLORAL. 453
Hirschsohn’s test for chloral alcoholate in hydrated chloral is
as follows:—Add to 1 gramme of hydrated chloral 1 Ce, of nitric
acid of sp. gr. 1.38; in the presence of chloral alcoholate yellow
vapors or a yellow liquid will result at ordinary temperatures,
or on warming.
Bromal, CBr,COH, bromal hydrate, CBr,CH(OH),, and bromal
aleoholates, are produced when bromine is employed instead of
chlorine in the interaction with alcohol, Joda/, CI,COH, is also
known.
_ Buryt CuHioran, C,H,ClCOH, originally, but erroneously,
termed croton ch/oral, is « product of the action of dry chlorine
on cold aldehyde. Butyl-chloral hydrate or hydrous butyl chloral
(wrongly called eroton-chloral hydrate), C,H,Cl,CH(OH), (tri-
chlorbutylidene glycol), occurs in pearly white trimetric laminew,
having a pungent but not acrid odor, and an acrid nauseous taste,
It fuses at about 172°F, (77.8° C.) to a transparent liquid, which,
in cooling, commences to solidify at about 160° F, (71,1° C.).
Soluble in about 50 parts of water, and in its own weight of
glycerin or of alcohol (90 percent.); it slowly dissolves in 20
parts of chloroform. The aqueous solution is neutral or but
slightly acid to litmus. It does not yield chloroform when heated
with solution of potassium hydroxide or with milk of lime (absence
of chloral hydrate).
The Acetic Series of Acids— Continued.
Propionic Acid (ethyl-formie acid), C,H,COOH, is produced by
oxidation of propyl! alcohol.
Butyrie Acid (propyl-formie acid), C,H,COOH, is formed by
general methods; also during the fermentation of cheese. It is
found as a glyceryl salt in butter (whence the name butyric acid).
Valerie Acid or Valerianie, C\H,COOH. There are several
isomeric varieties of this acid, the valeric acid from valerian and
angelica root, and that artificially formed from amy! alcohol
(see p. 425) being isovaleric acid, or isopropylacetic acid,
CH(CH,),CH,.COOH, the normal acid having the constitution
CH,CH,CH,CH,.COOH. |
Falnitie Acid, C,H, COOH, from fats ; stearicacid, C,, HCOOH,
a Stearicum, U.8. P.), from suet ; cerotie acid, C,.H.COOH,
rom beeswax ; and meliasic acid, C,,H,COOH, from beeswax and
from carnauba wax (from the surface of the leaves of Copernicia
cerjfera, a Brazilian palm), belong to the acetic series,
The Lactic Series.
Acids of the Laetie Series, CJA,(OH)COOH,—Thia series
embraces hydroxy-derivatives of the acetic series, one atom of
hydrogen being replaced by the hydroxy! group.
ORGANIC CHEMISTRY.
CH,COOH CH,(OH )\COOH
Acetic acid Hyd roxyacetic or glycolic acid
Though they possess only one carboxyl (COOH) group, yet,
having an alcoholic hydroxy! group, they may sometimes have
two of their hydrogen atoms replaced by metals.
They are best formed by hydrolysis of the nitriles produced by
the union of hydrocyanic acid with aldehydes or ketones ; also by
partial oxidation of glycols with dilute nitric acid ; and by acting
on monochloro-derivatives of the acids of the acetic series with
moist silver oxide :-—
2CH,CLCOOH + Ag,O + H,O = 2CH,OH.COOH + 2AgCl
Monochloracetic acid Glycollic acid
Carbonie Acid or Hydroxyformie Acid, OH.CO,OH, the first
of this series, has been studied already. Carbamide or Oren,
NH,.CO.NH,, the diamide of carbonic acid, is interesting his-
torically as being the first organic compound synthetically pro-
duced from inorganic sources (see p. 870), The acid amide of
carbonic acid, carbamic acid, NH,.CO,.OH, oceurs as an ammonium
salt, NH,,. co. ONH,, in the ammonium carbonate of pharmacy.
Ethyl carbamate or Urethane, NH,.CO.,OC,H,, (Aithylis Car-
bamas, U, &. P.)isa mild hypnotic.
Glycollic Acid (Hydroxyacetic acid), CH,OH.COOH, is found
in the leaves of the Virginia Creeper ; artificially it may be obtained
by carefully oxidizing glycol, and by the action of silver oxide on
dextrose and fructose,
Lactie Acid (Hydroxypropionic acid), C,H,(OH)COOH, Several
isomeric hydroxypropionic acids are known; the lactic acid of fer-
mentation (so-called ethylidene’ lactic acid), CH,CH,.(OH)jCOOR,
and sarcolactic acid, from flesh, being those of technical importance
(sce p. 332).
The Acrylic Series.
Acids of the Aerylie Series, C,H,,_\COOH.
Aerylie Acid, C,H,COOH, or C H, : CH.COOH, is formed by oxi-
dizing acrolein (ac ry lal le hyde, wee Glycerin) with silver oxide,
Crotonie Acid, ©, HH, COOH, or CH,CH : CH.COOH, formerly
supposed to be a constituent of croton oil, may be formed ay a
dizing croton-aldehyde, and by acting on allyl cyanide, C
with water and hydrochloric acid :-—C Hc ‘N +- 2H,O + Ware
C.H,CO.OH + NH,Cl.
" Oleic Acid, C,H, 0, is found as a glycery] salt in many fats and
oils,
' Substances having the CHyCH group are called ethylidene compounds,
Compare hydrated chloral, tric hlorethylidene glycol, CChkwCH, (OM jg.
LACTIC, GLYOXYLIC SERIES. 455
v
’
ACIDS OF ACETIC
TABLE SHOWING THE RELATIONS OF THE CHIEF ACIDS OF THE ACETIC, LACTIC, AND GLYOXYLIC SERIES.
ee A eS SS SS SD eS
Acids of the Acetic Series,
CyHya+,00.0H.
Methylic or
Formic H.CO.0H
Ethylic or
Acetic CH;.CO.OFE
Propylic or
Propionic C,H;.CO.0H
Tetrylic or
Butyric C,H,.cCO.0OH
Pentylic or
Valeric C,H,.CO.0H
Hexylic or
Caproic C,H, ,.CO.0H
Heptylic or
nanthylic C,gH,,..CO.0H
Octylic or
Caprylic C,H,,.CO.OH
Nonylic or
Pelargonic C,H,,.CO.0OH
Capric - - GQHy.CO.OH
Lauric . » C,He.-CO.GH
Mvristic . . CjsH,,.cCO.OH
Palmitic » . CyHs,.CO.0H
Stearic . - C,Hy.CO.OH
Arachidic . . C,H, CO.OH
Behenic . . Cy Hy.CO.OH
Cerotic » » CygHs5-CO.0OH
Melissic » » CygHy-CO.OH
Acids of the Hydrox
Series, C,H,,(0H)CO.OH.
Hydroxyformic or
Carbonic
Hydroxyacetic or
Glycollic
Hydroxypropionic
or Lactic
Hydroxybutyric
Hydroxypentylic
Hydroxycaproic
or Leucic
Hydroxyheptylic
Hydroxyoctylic
Hydroxydodecylic
Acids of the Dihydrox tic or Glyoxylic
tic or Lactic
1. OF Rerica, CoH ye. 4(0H) COOH.
OH.CO.OH ;
Dihydroxyacetic or
CH,OH.CO.OH Glyoxylic _ CH(OH),COOH
Dihydroxypropionic
C,H,OH.CO.0OH or Glyceric C,H,(OH),COOH
Dihydroxybutyric C,;H,;(OH),COOH
C,H ,OH.CO.OH
C,H,OH.CO.OH
C,H,,OH.CO.OH
C,H,,0H.CO.OH
C,H,,0H.CO.OH
C,,H,,0H.CO.OH
450} ORGANIC CHEMISTRY.
Preparation of Oleic Acid.—Olive vil is saponified by means
of potassium hydroxide and the resulting soap decom by
tartaric acid, which liberates vleic and stearic acids, The oleic
and stearic acids are heated with lead oxide, forming lead oleate
and stearate, the former being dissolved out from the latter by
ether, The ether is evaporated and the lead oleate treated
with hydrochloric acid, which liberates oleic acid.
Elaidie Acid (isomeric with oleic acid) is formed by passin
nitrogen peroxide into oleic acid; it is more stable than oleic acid,
distilling unchanged,
The Benzoie Series.
Acids of the Benzoie Series, CJH,,.,.COOH.—The acids of this
series are formed by oxidizing hydrocarbons, by the oxidation of
the corresponding alcohols, and by the hydrolysis of the correspond-
ing nitriles, There are numerous isomers of all these acids, ben-
voic acid excepted,
Benzoie Acid, CA,COOH, ( Acidum Benzoicunm, U.S. P.), occurs
naturally in gum ‘benzoin (Gum Benjamin), which contains from
12 to 15 pereent., the remainder of the gum ’’ being mainly com-
posed of two resins having the formule C,H,O, and C,H...
Bensoic acid may be obtained by oxidizing benza dehyde,
O,H,COH, which may be prepared from benzotrichloride (see p.
409), Toluene, C,H,CH,, may be directly oxidized into benzoic
acid, the methyl group (OH,) being resolved into COOH. Benzoic
acid may also be produced by heating hippuric acid (benzoyl gly-
cine or benzoyl glycocoll) with hydrochloric acid, p, 325, For
other modes of obtaining benzoic acid artificially, see p. 321. Ben-
zoic acid heated with lime yields benzene :-—
CH.COOH + CaO = CH, _ CaO,
Benzoic Acld =—6s Calolum oxide Benzene Calcium carbonate
Beasaldehyde, CSH,COH (Benzaldehydum, U.S. P.), forms the
greater part of oil of bitter almonds (see Amygdalin, p. 497). Tt is
a colorless liquid, soluble in 30 parts of water, and in all
tions im ether and alcohol. Like other aldehydes, it for a
crystalline compound with acid sodium sulphite—in this case
OH.OOOH NaHSO,
Benrey/ f ‘Morule, CH OCI, results from the action of chlorine
on benzaldehyde or of phosphorus pentachloride on benzoic acid.
Benzaldehvde also results from the oxidation of the benzyl aleohal
(CL\HLOH) of balsam of Peru.
HYDROXYBENZOIC SERIES, 457
The Hydroxybenzoie Series.
Acida of the Hydroxybenzoic Series, OA, ,QH.COOH,—Just
as the acids of the lactic series are related to the acetic series, so
are the acids of the hydroxybenzoic (or salicylic) series related to
ihe benzoic series,
CH,COOH CH,OH.COOH
Acetic acid Hydroxyacetic or glycollic acid
C,H,COOH ©,H ,OH.COOH
Henzoie acid Ortho-hydroxybengzule or salicylic acid
Salicylic or Ortho-hydroxybenzoie Acid, CH ,OH.COOH (Acidum
* Salicylicum, U.S. P.). Salicylic acid may be made by the oxida-
tion of salicylaldehyde (wide infra). Sodium salicylate may be
prepared by the action of carbonic anhydride on sodium-phenol
(Kolbe). To accomplish this, phenol is mixed with sodium
hydroxide, forming sodium-phenol, or sodium carbolate, C,H,ONa,
The sodium-phenol is then saturated with carbonic anhydride at
the ordinary temperature, by which sodium phenyl! carbonate is
produced. The latter on being heated in closed vessels is trans-
formed into sodium salicylate. From this salicylic acid may be
obtained by the action of hydrochloric acid, and it may be purified
by recrystallization from alcohol. It is identical with the natural
acid,
C,H,.ONa + CO, = C,H,0.CO,ONa
Sod{uni-phenol Sodium phenylearbonate
0,H,0.CO.ONa = C©,H,OH,CO,ONa
Bodium Sodium
phenylearbonate salicylate
Salicylic acid, like phenol, is a powerful antiseptic but is free
from the taste and smell of phenol, It is only slightly soluble in
cold water, but readily soluble in hot water, alcohol, ether, and
in aqueous solutions of such alkali-metal salts as borax, sodium
phosphate, or potassium citrate, which it converts into acid salts
with formation of a salicylate. A similar antiseptic ereaotie acid
(hydroxytoluic acid, C,H,OH,.CH,.COOH) is similarly obtained
from cresol or cresylic acid, C,H,OH,CH,. Ferric chloride pro-
duces x violet coloration with both salicylic and cresotic acids.
Both acids have antipyretic properties. The alkali-metal salicy-
lates, and probably therefore the cresotates, are very feeble anti-
septics, Sodium salicylate (Sodii Salieylas, U. 8. P.), (N aC H,O,),,
H.O, made by neutralizing salicylic acid with sodium hydroxide
or carbonate, forms small, colorless scales, or tabular crystals,
soluble in alcohol, and readily soluble in water, Ammonium Sali-
cylas (Ammonii Salieylas, U.S. P.), ia avery similar salt. As phenol
often contains cresylic acid, commercial salicylic acid may contain
cresotic acid, An alcoholic solution of salicylic acid allowed to
458 ORGANIC CHEMISTRY.
evaporate spontaneously (exposure to dust being avoided), should
leave a white residue free from color even at the points of the
crystals. Jodosalicylic acid, CJH,1O,, and di-iodosalicylic
C.H,1,0,, are used in medicine ; as also is acetylsalicylic acid,
C,H, SOHO which is known as «aspirin,
Salicylaldehyde, or ortho-hydroxybenzaldehyde (salicylol, sali-
evlous acid, salicyl hydride), C.H,OH.COH.—Found in the easen-
tial oil of meadow-sweet (Spirea ulmaria) ; also obtained by the
oxidation of salicin. It may be artificially formed by the action
of chloroform on sodium-phenol,
Preparation.—Mix 10 parts of phenol with 20 parts of
sodium hydroxide dissolved in 30 parts of water in a flaske
having an upright condenser, and gradually add 20 parts of
chloroform. After heating the flask on a water-bath, until all
chloroform has disappeared, add excess of hydrochloric acid,
when a red-violet oil will rise to the surface. Pour the con-
tents of the flask into a retort, and pass steam through it till
no more aldehyde comes over. The reaction is as follows :—
C,H,ONa + 3Na0OH + CHC, = C,H,ONa.COH -+ 3NaCl 4+ 20,0
Sodium- chloroform Sodiu m salicyl-
phenol aldehyde
Sodium salicylaldehyde, treated with hydrochloric acid and dis-
tilled, gives salicylaldehyde :—
C,H,ONa.COH + HCl = C,H (OH)COH + Natl
Sodium salicyl- falicylaldehyde
aldehyde
The oil which passes over (orthohydroxybenzaldehyde) may be
purified from phenol (with which it is always contaminated) b
treating with acid sodium sulphite, which forms a compound wi
the aldehyde, leaving the phenol which may be removed by dis-
solving it in ether, An isomeric salicylaldehyde (parahydroxy-
benzaldehyde) is formed along with the ortho-aldehyde, and
remains dissolved in the water in the retort, from which it is pre-
cipitated on cooling.
Methyl Salicylate, CH,C,H,O,, formerly known as ‘ gaultherie
acid,’’ forms the chief part, at lenst 90 ites of the essential
oil of gaultheria (Oleum Gaultheria, U. 8. P.) or winter-green,
(Gaultheria proc ~umbens, the fresh leaves of which yield about 0.4
percent, of oil), It also occurs in several species of violet (Man-
delin). Oijl of sweet birch ( Betula lenta) is methyl salicylate.
Gaultherin, a glucoside existing in the bark of Betula lenta, when
decomposed by mineral acids, by alkalies, or by heating the
aqueous solution to 180°-140° CG. , Yleldsac ~arbohydrate und methyl!
salicylate. Methyl Salicylas, U. 8. P., is produced synthetically,
TRIHYDROXYBENZOIC SERIES. 459
Phenyl Salicylate, C,H,OH.CO.OC,H,, (Phenylia Salicylas,
U. &. P.), or sa/ol is an antiseptic, antipyretic, anti-rheumatic
remedy. It is white, crystalline, soluble in alcohol, almost in-
soluble in water, and has a faint aromatic odor.
Othoform, a new anesthetic, is the methyl ester of para-amido-
meta-hydroxybenzoic acid.
VANILLIN or METHYLPROTOCATECHUIC ALDEHYDE, ( Vanil-
linum, U. 8. P.), C,H,O, or C,H,(OH)(OCH,)CHO, is the sub-
stance to which the odor and flavor of vanilla are due. It also
occurs in Siam benzoin, Hosa canina, etc. The white crystals
commonly found on vanilla ( Vanilla, U. 5, P.), (the prepared un-
ripe pods of Vanilla planifolia), termed vanillin, were found by
Carles to be a weak acid. It occurs in vanilla to the extent of
from 1} to 8 percent. Vanillin has in recent years been prepared
artificially by Tiemann and Haarmann from coniferin, a glucoside
existing in the sapwood of pines. The substance remaining after
the removal of glucose from coniferin, or, indeed, coniferin itself,
by action ofa mixture of potassium dichromate and sulphuric acid,
yields vanillin. It may also be obtained by a series of reactions
starting from that of carbonic anhydride on potassium-phenol ;
also from the eugenol of oil of cloves. By action of hydrochloric
acid, vanillin yields methyl chloride and protocatechuic alde-
hyde. Artificial vanillin is now manufactured by various patented
methods,
The Trihydroxybenzoic Series.
Acid of the Series, C,H, ,(OH),COOH, Gallic Acid, or tri-
hydroxybenzoie acid, C,H(OH),COOH (see p, 843), By the
elimination of one molecule of water from two molecules of gallie
acid, tannic acid is produced,
. { COOH
COO CH, (OH)
OH, | (OM), Lo :
( COOH
. ' (O H),
+ H,O
C,H
OO
CH, }
(On),
Gallic acid Tannic acid
Gallic acid, by the action of heat yields pyrogallol or pyrogallic
acid and carbonic anhydride,
O,H,(OH),COOH = ©,HOH), + CO,
460 ORGANIC CHEMISTRY.
The Cinnamie Series.
Acids of the Cinnamic Series, C,H, ,COOH.—Cinnamic acid,
C.H,COOH, may be obtained from She anaes of tolu and Peru,
and from storax. It may be made artificially by aid of Perkin's
reaction, which consists in heating 2 parts of benzaldehyde with
3 of acetic anhydride and one of sodium acetate.
1. Balsam of Peru (Balsamum Peruvianum, U. 8. P.), an exu-
dation from the trunk of Myroxylon Pereira, is a mixture of oily
matter with about one-quarter or one-third of resinous matter and
6 percent. of cinnamiec acid. The oil, by fractional distillation in an
atmosphere of carbonic Tag bytes, under diminished pressure, fur-
nishes benzyl aleohol, C,H.CH,OH, a benzoate, O,H.CO. toy
and benzyl cinnamate, c H, co. OO,H , or cinnamein ( raut).
action of alcoholic solution of potassium hydroxide it vield
potassium benzoate and cinnamate, and benzyl alcohol ; also ein-
namyl aleohol, OJH,CH,OH, otherwise known as peruvine or
atyrone, It also often holds it in solution welacinnamein or styracin,
C,,H,,0,, polymeric with cinnamaldehyde, C,H,COH. The resin
of balsain of Peru seems to result from the action of moisture on
the oi], Any admixture of resin, oil, storax, benzoin, or copaiba,
with balsam of Peru is detected by mixing 6 grains of slaked lime
with 10 drops of the balsam, when a soft product results if the
specimen be pure, but hard, if impure ; further, the mixture, on
being warmed until volatile matter is expelled and charring com-
mences, gives no fatty odor, 2. Balsam of Tolu (Balsamum
Tolutanum U. 8. P.), is an exudation from the trunk of Mf
Toluifera ; in composition it closely resembles balsam of Peru, but
is more easily resinified, It contains benzyl benzoate and cinna-
mate, cinnamic acid, a small proportion of benzoic acid (Busse),
and about 1 percent. of a volatile hydrocarbon, tolene, Onn |
The cinnamiec acid crystals may be seen with a lens when a little
of the bulsam is pressed between two warmed pieces of glass. Old
hard balsam of tolu is a convenient source of cinnamic acid,
which may be extracted by the same process as that by which
benzoic acid is obtained from benzoin—namely, ebullition with
alkali, filtration, and precipitation by addition of hydrochloric
acid, In syrup of tolu, (Syrupus Tolutanus, U.S, P.), the cinnamie
acid is liable, if certain micro-organisms are present, to develop
carbonic anhydride and acetylene, the latter communicating an
unpleasant smell, C,H,O, = CO, + 4C,H,, 38. Storax is an oleo-
resin obtained from Liguidambar orientalis. It containga volatile
oil termed styrol, cinnamene, or cinnamol, C,H,,—which poasibly
(Berthelot) is condensed acetylene, 4C,H,,—cinnamic acid, styra-
cin, or cinnamyl! cinnamate, C,H,CO.OC,H,, and a soft and a
hard resin. Styrol differs from similar hydrocarbons in bei
converted into a polymeric solid, termed metastyro! or draco
on heating to about 400° F. (204.4° C,). For medicinal use,
DIBASIC ACIDS. 461
storax (Styrar, U. 8. P.), is purified by solution in alcohol, filtra-
tion, and removal of the alcohol by distillation. By oxidation
with potassium dichromate and sulphuric acid it yields an odor
resembling that of essential oil of bitter almonds,
Coumarin, CJH,O, (the principle of the Tonka bean), may be
obtained by acting ‘on the sodium-derivative of salicylaldehyde
with acetic anhydride and sodium acetate (Perkin).
DIBAsSIC ACIDS,
These have two carboxyl (COOH) groups in the molecule.
The Suecinie Series.
Acids of the Suceinie Series, C,H,,(COOH),.—These acids may be
formed by the oxidation of glycols, or by the action of water
and hydrochloric acid on the eyanides of the olefines, obtained by
acting on the olefine dibrom-addition products with potassium
cyanide,
Oxalie Acid, H,C,O, or (COOH),, is the first of this series, It
may be obtained by ‘oxidizing glycol, C,H,(OH),—
CH,OH COOH
4 2H,0
COOH
Glycol Oxalic acid
Also by the action of carbonic anhydride on sodium :—
200, -+ 2Na = Na,0,0,
Carbonic anhydride Sodium Sodium oxulate
For other methods, see Oxalic Acid, p, 302.
Oramide, CJO.(NH,),, the analogue of urea—carbamide,
CO(N H, \,—is formed on mixing ethy] oxalate with ammonia
water; ~ by passing cyanogen into aqueous hydrochloric acid,
ON, + 2H,O = (CONHL)..
" gosinie Acid, 0 .H(,COOR),. (See p. 339),
The Malice Series.
Acide of the Malie Series, CH, OH (CC OH ),.—Malic, or
hydroxysuccinic acid, CLH.(( )H) (C “ 10H), is obtained artificially
by acting on bromosuccinic acid, C,HyBr(COOH),, with moist
silver oxide, the bromine being replaced by erarexct It is con-
tained in unripe mountain-ush berries, morello cherries, etc. (See
p. 382.)
. , a ; PONE
Asparagin (amidosuccinamic acid), CLHLNH, COHO
(Sve p. 882),
ORGANIC CHEMISTRY.
The Tarlarie Series.
Acids of the Tartarie Series, C.H,,,(OH),(COOH),. —Tartarie
Acid, (dibydroxysuccinic acid), ,H,(OH),(COOH » may be ob-
tained by oxidizing erythrite, C,H,(OH),(CH,OF (See p.
444). For other modes of formation, see p. 305, There are four
isomeric tartaric acids, differing in their relation to polarized
light.
The Phihalie Series.
Acids of the Phthalic Series, C,Hy,.(COOH),.—Phthalie Acid,
C,H,(COOH),, is obtained by the oxidation of naphthalene and
naphthalene tetrachloride, or a mixture of benzene and benzoic
acid. By distillation it forms phthalic anhydride, C,H,O,, and
this, when heated with phenol and sulphuric acid, yields phenol-
phthalein, a light yellow crystalline powder, which, when dissolved
in alcohol, is used in alkalimetry on account of its property of turn-
ing reddish-purple in presence of the slightest excess of alkali,
There are three phthalic acids, ordinary phthalic or orthophthalic
acid, isophthalic or metaphthalic acid, and terephthalic or para-
phthalic acid. (See p. 411.)
TRIBASIC ACIDS,
These have three carboxyl (COOH) groups in the molecule.
Tricarballylie Acid, or propane-tricarboxylic acid C,H,.(COOH),, is
the first of these acids; its hydroxy-derivative is cifrie acid,
C,H ,(OH)(COOH), (hydroxy-propane-tricarboxylic acid), found in
a variety of fruits. It has already been described (see p. 308).
OTHER POLYBASIC ACIDS,
Tetrabasic acids—as pyromellitic acid, C,H,(COOH),—and hexa-
basic acids—as mellitic acid, C,(COOH),—are known.
KETONES,
Just as primary alcohols on losing hydrogen by oxidation yield
aldehydes, so secondary alcohols (see p. 417) yield ketones :—
OH, ,,CH,OH — H, C.H,,,,,COH (aldehyde)
(C,H,.4;),CHOH — H, = (C,H,,,,), CO (ketone)
Like aldehydes, ketones are converted by reduction with hydroe-
gen into the corresponding alcohols, Like aldehydes, ketohes
form crystalline compounds with acid sulphites. While, however,
aldehydes by oxidation yield corresponding acids, ketones yield
acids whose molecules have « smaller number of carbon atoms than
the original ketones.
463
TABLE SHOWING THE RELATIONS BETWEEN THE ACIDS OF THE ACETIC SERIES AND THE DIBASIC ACIDS.
w
Q .
5 Acids of the Acids of the Acids of the Acids of the Dihydroxysuccinic
x Acetic Seri Succinic Series, Hydroxysuccinic or Malic Series, or Tartaric Seric
oy C,H n+, COOH. C,H,,(COOH), CaH en-:(0H)(COOH), Cy 5 gn-3(0H),(COOH),
w
x
~ Formic Oxalic,
ag H.CO.0H COOH.COOH. —— ate
9
2,
xs
S) Acetic Malonic, Tartronic ore oor) Mesoxalic,
a CH,.CO.OH. CH,(CO.OH), CH.0OH.(COOH), C(OH),(COOH),
3
<x
PS Prope lis, Succinic, Malic (oxysuccinic), Tartaric (or dioxysuccinic),
ns C,H,.CO.OH. C,H,(CO.OH), C,H,.0H:(COOH), C,H,(OH),(COOH),
Q
=
a Tetrylic, Pyrotartaric Glutanic, Homotartaric,
a C,H,.CO.0H C, ,(CO.OH), ’ (C,H,.0H.(COOH), C,H (OH),(COOH),
464 ORGANIC CHEMISTRY.
Acetone, C,H,O, or dimethyl-ketone, (CH,),CO or CH,.CO.CH,,
Acetonum U. 8. P., the best known of the class, may be obtained
by strongly heating calcium acetate, carbonate remaining ;
(CH,COO),Ca = (CH,),CO + CaO, The calcium salts of other
fatty acids split up in a similar manner (hence perhaps the name
—from «éw, ted, I split, and the original acefone), yielding other
ketones, as propione, butyrone, valerone, ete. The mixed calcium
salts give corresponding ketones, Thus acetate and caprate yield
methyl-nonyl ketone, CH,—CO—C,H.,, the chief natural constt-
uent of oil of rue. Acetophenone or phen yl-methyl ketone, CH,
CO.CH,, is known as hypnone.
QUESTIONS AND EXERCISES.
Give general methods for the formation of aldehydes and acids.—How
is acetaldehyde prepared ?—Describe the reactions that oecur in the manu-
facture of chloral and hydrated chloral.—W hat is the nature of the action
of alkalies on hydrated chloral ?—Mentiou the characters of pure and
impure hydrated ‘chloral.— What relation has valeric acid to amy! aleohol ?
Give the relations between the acetic and lactic series of acids.—To what
series do the following acids belong :—oleic, butyric, oxalic, aud citric ?—
How is benzoic acid prepared ?—Give the differences between balsam of
Peru, tolu, and gum benzoin.— How is oil of bitter almonds prepared, and
how can it be distinguished from so-called artificial oil of bitter almonds ?
—(Cive methods of preparing artificial salicylic aldebyde and acid.—Give
systematic names of tartaric, succinic, carbonic, salicylic and citric acids,
Volatile Oils.
The Volatile or Essential Oils exist in various parts of plants.
They usually are mixtures of the liquid hydrocarbons or el@oplena
(from éatov, elaion, oil, and srroua:, optomai, to see) with oxidized
hydrocarbons, whic ‘+h are commonly solid or camphor-like bodies
termed stearoptens (from orfap, stear, suet), and which on cooling
often crystallizes out; or on distilling an oil the stearopten may
remain in the retort, being less volatile than the eleopten. The
volatile oils often are associated with further oxidized substances
termed resins,
The tendenc i of ‘the results of recent investigations is to show
that instead of the e shi aracteristic odor of an essential oil being due
to one single princip: al constitue nt, the other bodies present have a
distinct influence in de termining the odor. Oils of CArAWAY, anise,
and |i lee are e examples. of those i in whic th the aroma is due to a
single odorous substance—c arvone, anethol, and linulol ; but in
many volatile oils thee onditions are more ¢ complex, Rose oil affords
a striking example of the import: ant influe! nee which combinations
of odoriferous hodies sometimes ¢ xerci ‘ise on the pe ‘rfume: the oils
of rose, geranium, and pi almarosa cont: ain ap proximately the SMe
KETONES. 465
percentage of geraniol, which is identical in the three oils, While,
however, geranium and palmarosa oils are valued in proportion to
the amount of geraniol they contain, the value of rose oil depends
upon the various other substances present.
The process by which volatile oils are usually obtained from
herbs, flowers, fruits, or seeds, may be imitated on the small
scale by placing the material (bruised cloves or caraways, for
instance) in a tubulated retort, adapting the retort to a Liebig's
condenser, and passing steam, from a flask, through a glass
tube to the bottom of the warmed retort. The steam in its
passage through the substance takes up some of the vapor of
the oil and carries it into the condenser, whence, cooled and
liquefied, it flows along with the condensed water, into the
receiving vessel, where it will be found floating on the water.
It may be collected by running off the distillate through a
glass funnel having a stopcock in the stem, or by letting the
water from the condenser drop into a test-tube or similar tube
which has a small hole in the bottom, and is placed ina larger
vessel containing water, the water and oil being subsequently
run off separately from the tube as from a pipette. The water
will in most cases be the ordinary official medicated water of
the material operated on (Aqua, Anisi, Aurantii Florum,
Cinnamomi, Feniculi, Menthe, Piperite, Menthe Viridis,
Rose). Volatile oils, like fixed oils, stain paper ; but the stain
of the former is not permanent like that of the latter. Oils of
lemon and orange are sometimes obtained by mere pressure of
the rind of the fruit. Volatile oils are “concentrated” by
removing inodorous terpene, whereby theso-called terpeneless
oils are obtained.
The presence of alcohol in an essential oil] may be detected and
its quantity estimated by shaking with an equal bulk of pure
glycerin, The latter dissolves the alcohol, and is augmented in
volume according to the amount of alcohol present (Bottger),
(For tests for alcohol, see p, 423.)
A large number of volatile oils are employed in medicine, either
in the pure state, in the form of saturated aqueous solutions
(medicated waters), or solutions in alcohol (Spiritue Amyqdale
Amare, Anisi, Cinnamomi, Caultheria, Juniperi, Lavanduler,
Menthe Piperita, Mentha Viridis, or as \eading constituents in
various barks, roots, leaves, etc. Perfiemes (‘* scents’? or ‘eagences,”’
including ‘* layender-water '’ nnd ‘‘eau de Cologne’’) are for the
most part solutions of essential oils in alcohol (45 to 90 percent. ),
or spirituous infusions of materials containing essential oils,
The following oils are, directly or indirectly, included in the
a0
466 ORGANIC CHEMISTRY,
Pharmacopzeias' :—1. Volatile oil of Bitter Almond (see p. 497).
2. Oil of the fruits of Ajwain or Omum, Carum Ajowan, or
Ptychotis Ajyowan, contains cymol or cymene (C,H,,), and a
stearopten (Ajwainka-phul, flowers of ajwain) identical with thymol,
C,,H,,0. 3. Oil of Dill, a pale, yellow, pungent liquid of
sweetish warm flavor, distilled from dill- fruit; it contains a
hydrocarbon, anethene (C,H,,), and an oxidized oil (Col »
identical with the carvone of oil of caraway (Gladstone).
of Anise (Oleum Anisi, U.S. P.), a colorless or pale yellow liquid,
of sweetish warm flavor, distilled in Europe from the anise fruit
(Pimpinella anisum), but chiefly in China, from the fruit of star-
anise (J//icium verum),; it isa mixture of a hydrocarbon, isomeric
with oil of turpentine, and anethol, a stearopten (C,,H,,O) which
crystallizes out at low temperatures. The melting point of anethol
is 70° F, (21.1° C.) (Moreau and Chauvet), Oil of Anise congeals,
when stirred, at temperatures between 50° and 59° F. (10° to
15° C.), and should not again become liquid below 59° F. (15° C,).
The congealing point of the natural oils appears to be dependent
on the proportion of the fluid to the solid constituent, a very small
quantity of the former lowering the congealing and melting points
very considerably, 5, Oil of Betula (Oleum Betula, U.S. P.),
obtained from the bark of the Sweet Birch, Betula Lenta, Com-
pare methyl solicylate, p. 458, 6, Oil of Chamomile, a bluish or,
when old, yellow oil, of characteristic odor and taste, distilled
from chamomile-flowers (Anthe wae U.S. P.). The official variety
( Anthemis nobilis) yields about 0.2 percent. of an oil cere of
a hydrocarbon (C,,H,,) and an oxidized portion (CoH, O,) which,
heated with potash, gives potassium angelate (KC.H, 0 \, whence
is obtained angelic arid (HC, H 7),). Ace ording to Demareay,
Kopp, and Kébig, the oil is a mixture of butyl and amyl angel-
ates and similar bodies, Naudin has also obtained from chame-
miles anfhemen, a hydrocarbon crystallizing in needles. The
flowers of another variety (.Vofricaria chamomilla) contain a
stenropten (C,,H,, ()) having the composition of laurel-camphor,
7. Oil of Horse-radish root seema to consist mainly of ally ise-
thiocyanate, C,H,.NCS. 8. Oil of Orange peel (Oleum Aurantii
Crticis, U.S. P. ), and the oils of various species of Citrus; namely:
—9. Lemon (Oleum Limonia, U. 8. P., from Limonia Cortex,
U.S. P., the fresh outer part of the pericarp of the fruit of C
mediea, var. 3 Limonum): 10. Lime (Italian, from ( fimetta :
West Indian, from (. medica, var, acida); 11. Bergamot (from C
bergamia); 12. Cifron and a yariety of citron termed cedra;
reseinble each other in composition, all ee a variety of
limonene (heaperidene), a hydrocarbon, C,H,,, and a small
quantity of oxidized hydrocarbons [C, thet D, C..H,,0, amd
! The student is notexpected to remember, but to understand, all that
follows respecting the volatile oils.
VOLATILE OILS. 467
(Wright and Piesse) C,,H,,O,], etc. Lemon oil consists chiefly
of a limonene, C,H,,, boiling at 176° C., together with a small
quantity of phellandrene, Its chief aromatic constituents are the
aldehydes, citral, C,,H,,O, and citronellal, C,,H,,O. A terpene-
less oil of lemon has been described by Geissler, who states that it
excels the commercial oil in odor, flavor, and stability. Oil of
bergamot appears to owe its fragrance to 40 or 50 percent. of linalyl
acetate, C,H, .CJH,O,. It also contains a stearopten, bergapten,
C,.H,O, Expressed lime essence contains a soft resin, 13. Oil
of Neroli or Orange-Flower (distilled from the flowers of the bitter
orange tree, Citrus Aurantium, var, Bigaradia), the aqueous solu-
tion of which is official in the forms of water (Agua Auranfii
Florum, U.S. P. and Aqua Aurantii Forum Fortior, U.S. P.),
and syrup (Syrupus Aurantii Florum, U. 8. P.), contains a fra-
grant hydrocarbon (C,,H,,), colorless when fresh, but becoming
red on exposure to light, and an inodorous, oxidized hydrocarbon,
Strong acids, especially nitric, attack the oil in orange-flower water,
imparting to the fluid a rose tint. 14. Oil of Petit Grain, dis-
tilled from the leaves and shoots of the orange-tree, consists chiefly
of finaly acetate, C\JH,C,H,O,. 15, The leaves of Boldo (Peumua
Boldus), a Chilian shrub (tonic and hepatic), yield 2 percent. of
essential oi] (and, according to Bourgon and Verne, an alkaloid,
boldine). 16. Oil of Buehu-leaves (Buehu, U. 8. P.), consists
chiefly of a fluid oil, C\H,,O, holding in solution a crystalline
stearopten, diosphenol, C,,H,O,. 17, Oil of Cannabis indica, see
p. 474. 18, Oil of (the lesser) Cardamoms, from the seeds of
Elettaria. repena (Cardamomum, U.S, P.), freed from their peri-
carps, is chiefly a hydrocarbon (C,,H,,) isomeric with oil of tur-
wntine (terpilene and probably limonene) and a camphor resem-
bling turpentine-camphor (C,H,,, 3H,O), 19, Oil of Caynupret
(Oleum Cajuputi, U.S. P.), from the leaves of Melalluca Leucaden-
dron, is a mobile bluish liquid, consisting of Aydrona cajyuputene,
cajuputol, or eineal (eucalyptol), C,yH, OH, and terpincol as well as
butyric, valerie, and benzoic aldehydes. Fresh cajuput-oil has a
green hue, which is perhaps transient, for the color of the commer-
cial oil is due to copper (Guibourt and Histed): certainly the green
coloring-matter of pure cajuput-oil is organic and either oily or
chlorophylloid, 20, Oilof Coraway-fruit (Oleum Cari, U.S. P.,
from Corum, U.S. P.), is a mixture of cerrone (formerly called
earvol ) (C,oH,,O) and cerrene which is a limonene (C,,H,,). 21. Oil
of Cloves (Oleum Caryophylli, U. 8. P.), and of Pimento (Olewm
Pimente, U.S. P.), both heavier than water, consist of engenol
( Hugenol, U, 8. P.), (C,,H,,0,) and asesquiterpene, ©,,H,, (earyo-
phyllene in the ease of oi) of cloves, which contains also traces of
vanillin). 22. Oil of Caseari/la has not been fully examined.
23. Oil of Cinnamon and of Cassia is mostly cinnamic aldehyde
(C,H,COH), Cinnalactydum, U.S. P. It also contains eugenol
and phellandrene. Boiled with nitric acid, it yields benzaldehyde,
i
468 ORGANIC CHEMISTRY.
C,H,COH, and benzoic acid, C,H,COOH; with chlorinated lime
it yields calcium benzoate, (C,H,COO),Ca ; and with potassium
hydroxide it gives potassium cinnamate, CLH,JCOOK. The sp. gr.
of oi] of cinnamon (Oleum Cinnamomi, U. 8. P.), varies from 1.045
to 1.055, 24, Oil of Citronella, a Grass Oil, from Andropogon
nardus, is chiefly composed of eitronellal, C,H,,.0. Kremers also
obtains heptoic aldehyde,C,H,,O, a terpene (C,,H,,), ete. 25, Oil
of Copaiba (Oleum Copaibe, U _ 5. P.), and, 26, of Cubeb (Oleum
Cubeba, U.S. P.), contain sesquiterpenes, C,,H,,. The eubebene
of the latter oil is sometimes associated with hydrous eubebene, the
so-called cubeb camphor, C,H,OH. Oil of cubeb also contains a
small quantity of a terpene ©, H,,). 27. Oil of Coriander (Oleum
Coriandri, U. 5. P.), consists of coriandol, C,,H,,O, and a terpene,
C,,H,,. 28. The fruits of Cumin or Cummin ( Cuminum Cyminum),
an ingredient of many curry-powders, contain about 3 percent., and
those of Wafer Hemlock or Cowbane ( Cieuta virosa) about 1} percent.,
of an essential oil composed of cymol or eymene. C,,H,,, and euminic
aldehyde, C,H, COH, The latter is an aldehyde which readily unites
with alkali-metal bisulphites and yields by oxidation enminie acid,
C,H,,COOH. Cymol also occurs in Garden Thyme ( Thymus vul-
garis). 29, Oil of Erigeron, (Oleum Erigerontia, U.S. P.). 30, The
fresh leaves of Eucalyptus globulus, FE. oleosa, FE. conerifolia, FF.
dumosa, FE. odorata, and other ‘‘mallee,’’ ‘‘scrub,’’ or shrub-like
eucalypts, furnish about 1 percent. of an oil (Olewm Eucalypti,
U.8. P.), which contains from 40 to 60 percent. of cienol or
eucalyptol, C\oH,,0 (Lucalyptol, U.S. P.), boiling at about 176° C.,
freezing at 0° C., sp. gr. 0.925 together with pimene, O,,H,. £.
amygdalina yields an oi] which contains little cineol and much phel-
landrene (the latter more readily alterable than other terpenes, and
characterized by yielding a crystalline mass with nitrousanhydride),
E. maculata, var, citriodora, contains an aldehyde similar to that of
citronella. Different species of eucalyptus may yield oils differing
in specific gravity, flavor, and odor. It is now generally accepted
that the medicinal efficacy of eucalyptus oil is due to the cineol
which it contains, Like the turpentines the eucalyptus oils are
good solvents of resins, Their sp. gr. varies greatly—trom 0.030
to 0.040 below or above 0,900. Voi ry states that cineol is present
also in the oil of Lavandula spica, oil of spike or “foreign” oil of
lavender, Red qum is from the bark of /. rostrata and other ja
cies, and is used solely for its astringent properties. 31. #ife-
campane-root ( Inula Heleninm) by distillation with water yields
solid volatile Aelenin (C,H,0), inulol, a camphor-oil (C,,H,,0),
and inudie anhydride or lactone (C\ H,O,), as well as, according to
Marpmann, crystals of a/antie acid (C,\H,O,) and fluid alanfol
(C,H,,0) each more powerfully antiseptic than helenin, 32, Oi]
of Fennel (Olenm Feenicutli, U. 8. P.), obtained fi rom the fruit of
Freniculum, U. 8. P.), differs in odor, but contains the same proxi-
mate constituents as oil of anise. 383. Oil of Geranmm, or Cinger
VOLATILE OILS, 469
Grass oil, from Andropogon sclvenanthus, and various species of
Pelargonium, contains geraniol (C,,H,,O). Barbier and Bouveault,
however, give the name limonool to the essential oi] of Andropogon
scheenanthus, and state that it is different from oil of pelargonium.
$4. Grains of Paradise (Amomum melegueta), Guinea Grains or
Melegueta Pepper, Semina Cardamomi Majoris, contain essential
oil (C,,H,, and C,,H,,0) and a highly pungent principle, termed
by Thresh paradol, CH,,0,, isomeric with the capsaicin of the
same chemist, 35, Oil of Hedeoma (Hedeoma, U.S, P., the leaves
and tops of Hedeoma pulegivides) or American Pennyroyal ( Oleum
Hedeoma U.S. P.), contains pulegone (C,H,,0), and yields tsohep-
toie acid (C/H,,0,), and other substances (Kremers), 36, Oil of
Juniper (Oleum Juniperi, U.S. P.), contains pinene, O,,H,,, cadi-
nene, C,,H,,, and a crystalline substance which has been called
juniper camphor. 87. Oil of Lavender Flowers (Oleum Lavanduler
Florum, U.S. P.), contains linalool, linaly] acetate, and a minute
proportion of cineol; pinene, C,H,,, is present in some samples,
but is not a constant constituent, 38, Oil of Myreia, oil of bay,
or bayberry oil (sp. gr. 0.975 to 0.990) is obtained from the leaves
of Myrcia acris. It contains eugenol with some methyl-eugenol
and small quantities of other substances, 39. Oil or butter or
camphor of Orris ( [ris Florentine) is a soft solid lighter than water,
Fliickiger and Hanbury found it to be chiefly myristic acid asso-
ciated with a small quantity of essential oil, 40, Oil of Pepper-
mint (Oleum Mentha Piperite U.S. P.) contains several bydrocar-
bons, C,,H,,, menthone, ©,,H,,O, and other bodies, and deposits
crystalline peppermint camphor known as menthol, C,,H,,OH,
when exposed to low temperatures. The latter is official (Menthol,
U.S. P.). It is also yielded by the oil of Mentha arvensis (vars.
piperascens and glabra), 41, Pulsatilla :—Various species of
Anemone and Ranunculus yield an acrid oil which with water gives
poisonous crystalline anemonin (C,.H,,0,) and amorphous anemonie
aeid (C,,H,,0,). 42. Oil of Spearmint (Oleum Mentha Viridis,
U.S.P.), the common Mint of the kitchen garden, contains carvone,
O,,H,,O, and a terpene. 43. Oil of Pennyroyal (Mentha Pulegium)
consists chiefly of the ketone, pulegone (C\H,,O), 44. Oil of
Nutmeg (Oleum Myristica, U.S. P.), is composed of a hydrocarbon,
myristicene (O,,H),), and myristicol (C\H,,.O), and cymene
(C\oH,,) (Gladstone), Mace, the arillus or net-like envelope of
the nutmeg appears to yield similar bodies and also myristicin,
C,,H,,0, (Semmler), 45, Oil or Otto or Attar of Roses (Oleum
Rose, U, 8. P.), contains citronellol (C,,H,,OH), geraniol (C,,H,,
OF), and minute quantities of other constituents ; the odor is not
due to any single substance, but to the blending of geranio] and the
other constituents. According to Fliickiger, the solid hydrocar-
bon also present yields succinic acid as the chief product of its
oxidation by nitric acid, and in other respects affords evidence of
belonging to the paratlin series of fats. Agua How, U.S. P., is
470 ORGANIC CHEMISTRY.
obtained by diluting with water the official Aqua Rosmw Fortior.
The latter is ‘‘ water saturated with the volatile oil of rose petals,
obtained by distillation.” 46, Oil of Aosemary-tops (Oleum Ros- |
marini, U.S. P.), exists in the plant to the extent of from 1) to3 .
parts per 1000. It contains a hydrocarbon (C,,H,,) resembli
that from Myrtle, Myrtus communis, also camphor (C,,H,,O) an
borneol and cineol (C,,H,,O) in variable proportions, 47. Oil of
Rue contains methyl-nonyl-ketone, Cully or peg, tN |
as chief constituent. Gorup-Besanez and Grimm have ob ed
artificial oil of rue (C,,H,,0), as one of the products of the destrue-
tive distillation of calclum acetate and caprate (see Ketones).
According to Greville Williams oil of rue is chiefly euodice alde-
hyde (C,,H,,0), some lauric aldehyde (C,,H,,O) also being present,
48. Oil of Sage contains the hydrocarbon pinene, C,,H.,,, a
with thujone, C,,H,,O, and cineol and borneol, C,,H,,O. 49. Oi
of Savin (Oleum Sabine, U.S. P.), obtained from the tops of Juni-
perus Sabina, contains sabinol, C,,H,,O, and sabinyl acetate.
According to Wallach, it contains also a sesquiterpene, C,,H,,.
50. Oil of Eider-flowers occurs in the flowers in very small quan-
tity ; it has a buttery consistence ; it contains a terpene ( =
and probably a paraffin. 51. Oil of Sandal-wood (Olewm Santali,
U. 8. P.) is composed (Chapoteaut) of two substances: mostly o
santalal, an aldehyde having the formula C,,H,,O (boiling at 572°
F. 300° C.), and a small quantity of the corresponding alcohol hav-
ing the formula C,,H.,,0 (boiling at 590° F., 310°C.), It oceurs to
the extent of about 2) percent. in the fragrant white or yellow
sandal-wood of India, Santa/um album, a small tree of the natural
order Santalacew, and not to be confounded with the Pt
santalinus, a tree of the natural order Leguminos», which furnishes
the inodorous Red Sandal-wood or Red Saunders Wood or Bar-
wood of the dyer. 52. Oil of Sassafras (Oleum Sassafras, U.S.P.),
contains nine-tenths of its weight of Safrol or Sassafrol, C,,H,,O,,
(Safrolum U. 8. P.), also evgenol and a small quantity of a ter-
pene. Sassafras camphor, C,,H,,O, is deposited when the oil is
exposed to a low temperature. 53. Oil of Black Sassafras, so-
called, from the dried bark of Cinnamomum oliveri also contains |
safrol and eugenol as well as cineol and cinnamic aldehyde, 64. .
Oil of Mustard (Oleum Sinapis Volatile, U. 8. P.), consists of allyl
iso-thiocyanate, C,H,NCS, with small quantities of allyl cyanide,
C,H,CN (see p. 427). If contaminated with alcohol, its sp. gr.
is below 1,015. 55. Oil of Sweet Flag (Acorus calamus) contains
a terpene, ©\,H,,. (The rhizome is said to contain Acorin, CHO,
a bitter glucoside). 56. Oil of common garden Thyme | Oleum
Thymi, U. S. P.), contains eymene or eymol (C,,H,,), thymene
C,,H,,), and thymol and carvaerol (C,,H,,0). Thymol, U.S. P.,
may he obtained from oil of 7% ymus vulgaris, Monarda punctata,
or Curum copticum. Thymol crystallizes out when oil of thyme
or of ptychotis, ete., is kept at a low temperature for a day or two,
VOLATILE OILS, 471
Tt may also be obtained by shaking the oils with caustic alkali,
and treating the separated alkaline liquid with an acid, It may
be purified by distillation, or by crystallization from alcohol, It
would seem that as an antiseptic thymol is quite as valuable as
eurbolic acid. Thymol Iodide (Thymolis Jodidum) is official. 57.
Oil of Turmeric (Cureuma longa) is said by Jackson and Menke to
be chiefly an alcohol having the formula C,,H,OH. They name
it durmerol, It isa light yellow volatile oil, having the sp. gr.
0.902, It is to this oil that turmeric (heace curry powder, partly)
owes its flavor and odor. 58. Oil of Valerian-root ( Valeriane,
U. 8, P., from Valeriana officinalis) contains the two terpenes, cam-
hene and pinene, C,H, together with several borneol esters—
ormic, acetic, butyric, and, especially, iso-valeric. A sesquiter-
pene, C,,H,,, and some other substances are also present. Accord-
ing to Bruylants, the strongly-smelling iso-valeric acid does not
exist free in the oil, but is emed by the decomposition of the
borneol ester. Iso-valeric acid can rapidly be obtained from the
rhizome by oxidation with a mixture of potassium dichromate
and dilute sulphuric acid. The potassium salt is formed in quan-
tity when oil of valerian is allowed to fall, drop by drop, on heated
potassium hydroxide, and by the action of sulphuric acid on the
potassium salt thus produced, iso-valeric acid is obtained, Vatleri-
ana Wallichii furnishes an Indian valerian oil resembling, in its
general characters, the oil from V. officinalis, 59, Indian oil of
Verbena, Lemon-qrase Oil, or Indian Melissa Oil, is obtained from
Andropogon citratus, It consists mainly of citral associated with
small quantities of an isomeric aldehyde and of citronellal. 60.
Oil of Ginger (Zingiber, U.S. P.), is, according to Thresh, a com-
plex mixture of hydrocarbons and their oxidation products ; cym-
ene (C\)H,,) is present, a terpene, aldehydes, and ethereal salts,
64. The oil obtained from the so-called worm-seed (Artemisia
maritima) consists mainly of cineol (C,,H,,O), American Worm-
seed contains a volatile oil (Oleum Chenopodii, U. 8, P.).
Caoutchoue or India-rubber, and Gutta Percha,
Caoutchouc is the hardened juice of Dichopeia Gutta, Hevea
(several species), Castilloa elastica, Ureeola elastica, Ficus elastica,
and other plants. Heated moderately with sulphur, it takes up
2 or 8 percent. and forms vulcanized India-rubber; at a higher tem-
perature a hard horny product, termed ebonite or wuleanite, results.
The official India rubber (//astica, U. 8. P.), is ‘ the prepared
milk-juice of several species of Hevea,’’ Gutta Percha is the
concrete “drop’’ or juice of the percha (Malay) tree, Jronandra
gutta, and of other Sapotaceous plants, White gutta percha is
obtained by precipitating a solution of the ordinary gutta percha
in chloroform by the addition of alcohol, washing the precipitate
with alcohol, and finally boiling it in water and moulding it into
the desired form while still hot,
a
472 ORGANIC CHEMISTRY.
These two elastic substances, in the pure state, are hydro-
carbons (C,H,),, usually slightly oxidized. When caoutchouc is
distilled, a terpene, C,,H,,, called caoutchin, is obtained.
Camphors,
In addition to the stearoptens or camphors already mentioned as
being contained in or formed from volatile oils, there is one that
is a common article of trade. It is obtained from the wood of
Cinnamomum Camphora, or Camphor-laurel, in Japan (termed in
Europe, Dutch camphor, because imported by the Dutch) and in
China (known as Formosa camphor), by a rough process of distil-
lation with water, and is resublimed in this country (Camphora,
U. 8. P.). The formula of laurel-camphor is C,H,O. Sp. gr.
about 0.990; melting point, 175° C.; boiling point, 204° ©,
Bromine heated with camphor gives monobromated camphor
C,,H,,BrO) and hydrobromic acid. Recrystallized monobromated-
camphor occurs in white prisms (Camphora Monobromata, U.S. P.),
The essential oil, from which doubtless camphor is derived by
oxidation, is easily obtained from the wood, and is occasionally
met with in commerce under the name of liquid camphor or camphar-
oil, It contains hydrocarbons resembling terebenthene and citrene,
and hydrous camphor (C,,H,.O,H,O) as well as camphor, By
exposure to air it becomes oxidized and deposits common camphor.
Camphor distilled with phosphoric anhydride yields cymene,
C,,H,,. There is another kind of camphor, Borneo/, in European
markets, less common than laurel-camphor, but highly esteemed
by the Chinese; it is obtained from Dryobalanops aromatica, and
is denominated Sumatra or Borneo Camphor. It differs slightly
from laurel-camphor in containing more hydrogen, its formula
being C,,H,.O. It may be obtained by acting on camphor with
hydrogen, the camphor being dissolved in some inert liquid such
as toluene, and sodium added; the sodium forms a compound,
O,,H,,ONa, while the hydrogen thus liberated acts on another
portion of the camphor, forming borneol, C,,H ,;0 H—a better reault
being obtained if absolute alcohol is used instead of toluene
(Jackson and Menke). Borneo camphor 1s accompanied in the
tree by a volatile oil ( C\.H,,) isomeric with oil of turpentine,
This oil, borneene, is also occasionally met with in trade under the
name of liquid camphor or camphor-oil, but differs from laurel-
camphor oi] in not depositing crystals on exposure to air,
The constitution of the carmphors is still somewhat doubtful.
Camphor is soluble to a slight extent in water, about 1 in 700,
The official Camphor Water (Agua Camphorm, U. 8. P.), ia a
solution obtained by dissolving camphor in a little less than ita
own weight of alcohol, triturating the solution with purified tale,
RESINS.
permitting most of the alcohol to evaporate, then gradually adding
water to the residue, and filtering till clear,
Common camphor, and many other of the camphors, oily
hydrocarbons, and oxidized hydrocarbons, yield ecamphorie acid,
C,H,,(COOH),, (Acidium Camphoricum, U.8. P.), and camphor-
onie acid, C, H,(OH)(COOH),, when attacked by oxidizing agents.
Such reactions indicate natural relationships. Camphoric acid is
an antiseptic. Ceratum Camphore, Linimentum Camphore, and
Spiritus Camphore: are official.
Cantharidin, C\H,,O0,, the active blistering principle of can-
tharides (Cantharis, U.S. P.) and other vesicating insects (such
as Mylabris cichorti or Telini fly, Mylabris phalerata, and others
common in India), has most of the properties of a camphor or a
stearopten. Itslowly crystallizes from an alcoholic tincture of the
beetles, in fusible, volatile, micaceous plates. The following pro-
cess for the extraction of cantharidin is by Fumouze: Powdered
cantharides are macerated with chloroform for twenty-four hours;
and this treatment is repeated twice with fresh quantities of
solvent, the residue having been well squeezed each time, The
collected solutions are then distilled, and the dark-green residue
treated with carbon bisulphide, which dissolves fatty, resinous,
and other matters and precipitates the cantharidin, The precipi-
tate is placed on a filter, washed with carbon bisulphide, and
recrystallized from chloroform. Greenish and Wilson published a
process for the quantitative determination of cantharidin in can-
tharides, (See Pharmaceutical Journal, vol. \x., p. 255.) The
average amount found is six or seven partsin one thousand, Can-
tharidin is readily soluble in warm glacial acetic acid, and
still more readily in acetic ether orchloroform, Cantharides from
which the fat has been removed by petroleum ether yield their
cantharidin with great facility.
Massing and Dragendorff consider cantharidin to be an anhy-
dride, and that with the elements of water it forms cantharidie acid
(H,C,,H,,0,). Piccard gives to cantharidin the formula C,,H,,0,,
Homolka assigns to it the formula C,H,,0,CO,COOH.
Ceratum Cantharides, and Tinetura Cantharidis are official.
Resins, Oleoresins, Gum-Resins.
Resins seem to be products of the oxidation of terpenes and
the allied hydrocarbons; they occur in plants, generally in assovia-
tion with yolatile oils. They closely resemble camphors and
stearoptens, but are not volatile, and differ from oils and fats
chiefly in being solid and brittle, For convenience they are
classified as resins, oleoresins, and gum-resins, the distinctions
being founded as much on physical as on chemical properties,
Oleoresins are mixtures of a resin and a volatile oil,
Gum-resins are mixtures of a resin or oleoresin and gum,
474 ORGANIC CHEMISTRY.
Balsams are commonly described as resins or oleoresins which
yield benzoic and cinnamic acids; they are Benzoin (Benzoinum,
U. 8. P.), Balsam of Peru (Balsamum Peruvianum, U. 8. P.),
Balsam of Tolu (BSalsamum Tolutanum. U. 8S. P.), and Storax
(Styrar, U, 5. P.), and are respectively treated of under the
above-named acids.
Some oleoresins, containing neither of the above acids, are often
termed balsams (¢.g., balsam of copaiba,-and Canada balsam);
these are described under the head of Oleoresins,
Restns'.—Resin, rosin, or colophony (Resina, U. 8, P.), is the
type of this class, Its source is the oleoresin or true turpentine
of the conifers, a substance which by distillation yields spirit of
turpentine and a residuum of resin, ‘‘Brown’’ and ‘‘white’’ resin
are met with in trade. The former is the residue of American,
the latter of Bordeaux turpentine (from Pinus Abies, ete., and
Pinus maritima respectively). The chief constituents of brown
resin are pinte acid, HC,,H.O,, and sylvic acid, identical in com-
position but differing in properties (see Isomerism), the former
being soluble and the latter insoluble in cold alcohol. White
resin or ‘‘galipot’’ is chiefly pimarie acid, also isomerie with
pinie acid. Pinic acid, cautiously heated, yields colophonie or
colopholic acid. Resin, by destructive distillation, yields resin oi,
the first portion being ‘‘pale,’’ the next ‘‘blue,’’ and the third
‘green "’ resin oil. Mixed with other oils, these oils are used for
lubricating purposes and in the manufacture of printing ink.
Among the products of the destructive distillation of resin, Tich-
borne found ‘‘colophanie hydrate,’’ CyH,,O, HO, a white
inodorous crystalline substance, and by depriving this of water
obtained white crystalline colophonin, ©,,H,.0O,. Resin is soluble
in oil of turpentine, Contact with sulphuric aid immediately
colors it strongly red. 2. Arnicin C,H,O,, the chief acrid, and
one of the active, principles of the rootlets and rhizome of Arnica
and of the flowers (Arnica, U.S. P.), is a resin, and, probably ya
glucoside, 3, Cannabin, said to be the active principle of Indian
Hemp (Cannabis Indica, U. 5S. P.), was obtained in 1846 by T,
and H, Smith, and is aresin, According to Vignolo the essential
oil of Cannabis Indica, purified by distillation in ® current of
steam and extraction with ether, is a mobile liquid boiling at
248°-268°C, After repeated distillation from metallic sodium in
order to rem ove a stearopten, it yields a sesquiterpene, C ae ais
a mobile colorless oil of aromatic odor which boils at 206°, and
has a density of 0.897 at 15,3° C., and is slightly lwvo-rotatory,
This soon resinifies on exposure to air, and on. adding concen-
trated sulphuric acid to its chloroform solution the liquid becomes
first green, then blue, and red on heating. Vignolo concludes
' The student is not expected to remember, but to understand all that
follows respecting the resins.
RESINS. 475
that the ‘‘cannabene’’ prepared from this oil by Personne, was a
mixture. Preobraschensky has stated, and since re-asserted, that
the active principle is nicotine. Kennedy searched for nicotine
by two methods, but found none. Hay found an alkaloid, tefano-
cannabine; Siebold and Bradbury, also H. F. Smith, an alkaloid
termed cannabinine. Warden and Waddell, after careful investi-
gations, consider that the active principle of the plant has yet to
be isolated. Jahns finds choline present. The native names of
Indian hemp, that is, of the cultivated ‘‘ dried flowering or fruit-
ing tops of the female plants of Cannabis sativa,’’ are ganga and
gunjah. It is chiefly grown in Bengal. Guaza is the name of
the Bombay product which includes the wild plant. Both are
used for smoking, and form the equivalent of the tobacco of
western nations. Bhang, or sidee, consists of the dried leaves,
fruit, and twigs of the wild plant. Its infusion is used as a
beverage, as tea is in Europe and elsewhere, Hashish, made
from bhang, corresponds to Extractum Cannabis Indice, U. 8. P.
Charaa or churras is a resinous exudation of the plant, and is also
used for smoking. All these preparations are stimulating and
narcotic, 4. Capsieum-fruit contains a resin (p.477). 5. Castorin,
a resinous matter, is the name given to the chief constituent of
Castor, the dried preputial follicles and included secretion of the
Beaver (Castar Fiber), 6. Copal.—The best copal is the exuded
resin of trees of extinct forests, and is found beneath the surface
of the ground in the neighborhood of existing trees. It appears
to be a mixture of acids, but its character is still obscure.
Experiments by Wallach and Rheindorff show that when copal is
distilled, and the oily distillate washed with soda and distilled
with steam, a mobile liquid boiling at 40°-350° C. is obtained.
The lowest boiling portions of this liquid seem to contain iso-
prene; the portions boiling at 154°-164° consist principally of a
hydrocarbon of the composition C,,H,,, which was proved to be
pinene, and the fractions boiling at about 175° were found to
contain dipentene. 7. Doundaké-bark, an African febrifuge,
from Sarcocephalus exculentua, owes its activity to resinoid sub-
stances, according to Heckel and Schlagdenhauffen. 8. Dragon's
Blood is a crimson-red resin found as an exudation on the mature
fruits of a Rotang or Rattan Palm (Calamus draco). According
to Dieterich it contains a large proportion of aromatic esters, with
dracoalban, C,.H,O., dracoresen, C all,,0,, and other substances,
9. Ergotin, ia a very active resinoid constituent of Ergot ( Lrgota,
U. 8. P.), &¢, the sclerotium (compact mycelium or spawn) of
Claviceps purpurea, originating in the ovary of the common rye,
Secale cereale, According to Wenzell, ergot contains two alka-
loids, ecboline and ergotine, to the former of which, he says, the
activity of ergot is due. Blumberg considers these alkaloids to be
identical. Tanret states that an unstable alkaloid termed
ergotinine occurs in ergot to the extent of 1 per 1000 and that it is
- =
476 ORGANIC CHEMISTRY.
accompanied by a camphor; also ergosferin,
resembling cholesterin, Dragendorff and Podwissot
ergot owes most of its activiy to sclerotic or selerotinie sake present
to the extent of about 4 percent. Recent investigations seem to
show that cornutine is an active alkaloid of ergot, associated with
ergotinic and sphacelinic acids, picrosclerotine and i
The activity really seems to be due to a combination of alkaloids
and acids, and not to any one constituent, as no principle repre-
senting the full activity of ergot has been extracted. Ergot also
contains choline, which by decomposition may yield trimethylamine.
“Ergotin” (Extractum Ergote, U.S. P.), is obtained from ergot by
extraction with alcohol (60 percent.), and purification of the
age t. 10. Guaiacum-resin (see p. 501), 11. Jalap-rewin (see
502). 12. Kousso (Cusso, U.S. P.), yields yellow crystals of
- “resinoid substance readily soluble in alkaline liquids, Aosin or
koussin, Cy Hy Oy. It is, perhaps, an anhydride. 13, Mastic is
a resinous exadaion obtained by incision from the stem of the
Mastic or Lentisk tree. N early nine-tenths of mastic is maatichie
acid, CoH er a resin soluble in alcohol; the remainder consists
of masticin, C,,H,,0, a tenacious elastic resin, and a terpene having
the formula C C,H... 14. Mezereum, the ‘dried bark (abssieaie
U. & P.) of Daphne Mezereum, Mezereon, Daphne tlaureola,
Spurge Laurel, and of Daphne Gnidium, owes its acridity to a resin,
15. Pepper contains resin (see p.588). 16, Burgundy pitch is the
melted and strained exudation from the stem of the Spruce Fir,
Picea excelsa. The term Burgundy is a misnomer, the resin never
having been collected in or near Burgundy; Finland, and to a
small extent, Baden, and Austria being the countries whence itis
derived. Its constituents closely resemble those of ordinary resin. Tt
is often adulterated and imitated by a mixture of resin with palm-
oil, water, etc., from which it may readily be distinguished by its
duller yellow "color, highly aromatic odor, greater solubility in
alcohol, and almost complete solubility in twice its weight of
glacial acetic acid (Hanbury). 17. Podophyllum-resin—In pre-
paring the resin of podophyllum, or May-apple (Resina :
U.S. P.), an alcoholic extract of the rhizome and rootlets (Podo-
phyllum, U. 8. P., from Podoph yllum peltatum), is pou into
acidulated water; the resin is then deposited. According to
Guareschi, podophyllum contains a glucoside resembling con-
volvulin. Podwissotzki has extracted from podophyllum a small
quantity of crystalline « oloring matter, fat, a bitter crystalline acid,
a bitter crystalline neutral principle, and an amorphous acid resin,
Kirsten states that the latter yields a crystalline active substance,
podophyllotoxin, C,,H,,O, (Dunstan and Henry, C ‘yH,,0,) which
seems to be the active principle both of Po vdophylian peltatum, the
U.S. drug and P. emodi, the Indian plant. Pyrethrin is the
acrid resinous active principle of the root of Amang dee pyrethrum
or Pellitory-root (Pyrethrum, U.S. P.). According to Buchheim,
OLEORESINS. 477
alkalies break it up into piperidine and pyrethric acid. The erys-
talline poisonous principle obtained by Bellesme from Pyrethrum
carneum, the powder of which (and J. roseum, and especially P.
cinerariefolium, or Dalmatian Insect Powder) is the well-known
**insecticide,’’ has not yet been analyzed. 19, The resins of
Rhubarb. (‘See Chrysophanic Acid.) 20. Rottlerin, CyH,,Oy, is
the erystalline resin from Kamala, the minute glands that cover
the capsules of Roittlera tinctoria: to this and, apparently, allied
resins (isorottlerin, A. G. Perkin) Kamala owes its activity as an
anthelmintic.
OLEORESINS,—1. Oleoresin of aspidium (Oleoresina aspidii,
U. 8. P.), is obtained from the male fern (Dryopteris filix-mas) by
exhausting the finely-powdered rhizome with acetone. 2, ‘‘Cap-
sicin,’’ a term suggestive of a definite chemical substance, is a
name somewhat unhappily accorded to an indefinite substance, an
Oleoresin (Oleoresina Capsici, U. 5. P.), obtained by digesting
Capsicum fruit (Capsicum, U. 8. P.), in acetone. Besides volatile
oil and resin, capsicum fruits contain much fatty matter which
Thresh states is chiefly free palmitic acid. (See also Capsicine
and Capsaicin, p.581). 3, Copaiba (Copaiba, U. 8, P.), is a mixt-
ure of essential oil ( sHy) copaivadl, oR (Strauss), with 2 or
more percent. of Sevenchk resin, and 30 to 60 percent. of a yellow
dark resin consisting mostly of copaivie acid, C,,H,,O,, with oy:
copaivie acid, C,gH,,O; (Fubling), and metacopatvie “acid, C
(Strauss). Copaiba, containing about equa] parts of this acid oH
of the oil, heated with a fourth of its weight of the official magne-
sium carbonate, yields a transparent fluid, owing to the formation
of magnesium copaivate and solution of this soup in the essential
oil, With an equal weight of the carbonate, enough soap is
produced to take up the whole of the essential oil, and form a
mass capable of being rolled into pills. A much smaller quantity
of calcined magnesia, as might be expected, effects the same result;
but more time, often several days, is required before the inter-
action is complete. Quicklime has a similar effect. Copaiba,
unlike 4, Wood-oil or Gurjun Balsam, a similar oleoresin from
Dipteroearpus turbinatus is almost entirely soluble in absolute
alcohol and in petroleum spirit. Copaiba is often slightly fluo-
rescent ; Gurjun balsam is highly fluorescent. The stated analogy
of Gurjun balsam to copaiba is borne out by its chemical com-
position; for by distillation it yields about 40 percent. of an
essential oi] identical in composition with oil of copaiba, the non-
volatile portion being resinous. The adulteration of copaiba with
fixed oil is best detected by heating 20 or 30 drops in a capsule
until all essential oil has evaporated. (Turpentine is betrayed by
its odor during this evaporation.) The residue, copaiba reain, is
brittle if pure, and more or less sticky or soft if fixed oil is present.
5. Oleoresin of cubeb, an alcoholic extract of cubeb decanted from
waxy matter, is official, Oleoresina Cubebia, U.S. P. 6. Elemi
478 ORGANIC CHEMISTRY,
is an exudation from a tree growing in the Philippine Islands.
It consists of volatile oil (C,,H,,) with 80 or more percent. of two
resins, the one (C,H,.O,) soluble in cold alcohol, the other,
Amyrin, (C,H,),,H,O, almost insoluble, associated with Amyrie
acid, (C.H,),O, (Buri). There is an e- and a §-amyrin, each hay-
ing the formula C,,.H,OH (Vesterberg), It also contains small
quantities of two crystalline bodies soluble in water, Bryoidin,
(C.H,),,3H,0, and Breidin (Fliickiger). The Jeacin of Stenhouse
and Groves is either identical with amyrin, or perhaps has the
formula (C,H,),,H,O. All these substances are probably hydrous
terpenes, 7, Wood-tar (Pix Liguida, U. 5. P.), is a mixture of
several resinoid and oily substances (among others Creosote, see p,
484) obtained by destructive distillation from the wood of Pinus
palustris and other pines. When heated, it yields a terebinthinate
oil (Oleum Picis Liquide, U.S. P.) and a residue of pitch, (Earth
Pitch ov Asphalte, appears to be a partially oxidized petroleum.)
Oleum Cadinum, U.S. P., ‘ Huile de Cade,’’ or Juniper Tar Oil,
is the product of the similar destructive distillation of Juniperus
Oxycedrus. 8. Turpentines.—These oleoresins have been men-
tioned in connection with oi/ of turpentine, their volatile constit-
uent, and resin, their fixed constituent, 9, Common Frankincense
is the concrete turpentine of Pinus palustris and Pinus tarda,
10. Canada Balsam (Terebinthina Canadenis, U. 5. P.), 18 largely
gathered in the province of Quebec, and is the turpentine or oleo-
resin of the Balin of Gilead Fir (Abies balsamea). 11. Sumbul-
root (Sumbul, U. S. P.), contains 9 percent. of resin, to which
probably it owes its stimulating properties. The resin consists of
two parts, one soluble in ether and the other in alcohol, together
with valeric, sumbulic, and sumbuolic acids. By dry distillation
it yields a blue oil, 12. Oleoresin of Lupulin (Oleoresina Laupu-
fin, U. 8. P.) is an ethereal extract of the yellow glandular
powder (Lupulinum, U.S. P.), attached to the small nuts at the
base of the scales which form the aggregate fruit of the Hop
(Humulus, U.S. P.). It contains a volatile oil which is chiefly
composed of a sesquiterpene, an oxidized oil or resin, a bitter
extract containing the hop-bitter, lupulinic acid, C O,, and
tannic acid. It generally contains a good deal of ea rthly ust, but
should not yield more than 12 percent. of ash, and not more than
4) perce nt, of matter insoluble i nether. 13. Oleoresin of
(Oleoresina Piperis, U. S. P.), is obtained by exhausting powdered
OT LAO aD, lle oldie aR zy = ike es aera, 2 sy:
black pepper by percolation with ncetone, removing the acetone by
Spee st od epaniamsonn. Scxporstion;! Sih oes
cotton to separate the oleoresin from the crystals of piperme that
have been deposited, 14. Olearesin of Ginger ( Oleoresina Zingiberia
U.S. P.), is obtained from ginger, in powder, by exhausting it
with acetone in a percolator anid freeing the percolated liquid
from acetone by distillation and s
warm place.
Shy et — = : = =
ayy ALT As eV [ \
pontaneou evaporation 1m @
GUM-RESINS. 479
GUM-RESINS.—1. Ammoniacum is an exudation from Dorema
Ammoniacum, It contains 20 percent. of gum, a little volatile
oil, and 70 percent, of resin (C,,H,O,—Johnston), 2. <Asafetida
( Asafintida, U. 5. P.), isa gum-resin obtained, by incision, from
the living root of Feru/a fetida, It contains from 50 to 70 per-
cent, of a resin which is partly /ferudaiec acid, C,H. O,, 25 to 30
percent. of gum (about two-thirds arabin, one-third bassorin,
p. 494), a little vanillin, and 3 to 5 percent. ‘of volatile oil, which
(Semmiler) ee “te sulphur compounds, C,H,,5,, and C,,H,5,,
two terpenes, C,H,,, and a sesquiterpene, i 3. ‘dapher
dium, an old drug a lich is an emetic and purgative gum-resin,
contains an amorphous active resin, crystalline euphorbon, C,H,,O,
and other substances, 4, The ordinary or Siam Gamboge (Cam-
bogia, U.S. P.), of European trade is obtained from the Garcinia
Hunburii ; the gamboge of India from G, morella, When of best
quality, it contains about 20 percent. of a gum, and 75 to 80 per-
cent. of a yellow resin termed gambogie acid, C,H,O, 5. Gal-
banum consists of about 25 percent. of gum, about 65 percent, of
resin, and 9 or 10 percent, of volatile oil. Moistened with alcohol,
and then with hydrochloric acid, some varieties of galbanum yield
a purple color, Galbanum heated for some time to 212° F,
(100° C.) with hydrochloric acid, the liquid separated and shaken
with ether or chloroform, and the lutter evaporated, yields some-
what less than | percent. of colorless acicular crystals of wmbelli-
Serone, CyH,O,. According to Fliickiger and Hanbury, umbelli-
ferone is soluble in water; its solution exhibits, especially on
addition of an alkali, a brilliant blue fluorescence which is
destroyed by an acid. A small fragment of galbanum im mersed
in water, shows fluorescence on the addition ofa drop of ammonia,
The same phenomenon occurs with asafetida, and slightly with
ammoniacum ; it is probably due to traces of umbelliferone pre-
existing in these drugs. Umbelliferone is also produced from
many other aromatic umbelliferous plants, as Angelica, Leviatiewm
(Lovage, the basis of an old cordial or liquor), and Meum, when
their respective resins are submitted to dry distillation : alse from
the resin of Daphne mezereum. The fluorescence of umbelliferone
may be shown by dipping bibulous paper into water which has
stood for an hour or two on lumps of galbanum, and drying it.
A strip of this paper placed in a test- tube of water with a drop of
ammonia will give a superb blue solution, instantly losing its color
on the addition of a drop of hydrochloric acid, 6. Myrrh
(Myrrha, U. 8. P.), an exudation from the stem of Commiphora
Myrrha, contains about half its weight of soluble arabinoid gum,
10 percent. of insoluble gum (probably bassorin), 24 of volatile
oil, isomeric with thymol and ecarvone (Kohler), and about 25
percent. of resin (my rrhic acid). 7. Olibanum or Thus masculum,
or Aralian Frankincense (from various spec ies Of Bowwellia is
about one-third gum and nearly two-thirds resin (CHO), with
480 ORGANIC CHEMISTRY.
a little hydrocarbon (C,,H,,) und oxidized hydrocarbon yolatile
oils, It has always been an important ingredient of ineense—
myrrh, storax, benzoin, and such fragrant combustible resinous
substances, being other constituents, 8, Scammony (see p. 505).
Grum-resins need only to be finely powdered and rubbed ina
mortar with water to yield a medicinal emulsion, in which the fine
on of resin are held in suspension by the aqueous solution
of gum.
oo
QUESTIONS AND EXERCISES,
_ Whatare the general chemical characters of volatile oils ’—How do vola-
tile oils usually differ chemically from fixed oils?—Describe the usual
process by which volatile vils are obtained.—How does natural turpentine
differ from turpentine of trade Y—With what object is commercial turpen-
tine rectified }—What is the chemical nature of India-rubber and gutta
percha ?—How is India-rubber vulcanized and converted into ebonile or
tulcanitle?—Mention the difference in composition between the volatile
oils of Anthemis nobilis and Matricaria Chumomilla—Give the systematic
name for oil of horse-radish,—State the general composition of the oils of
lemon, lime, bergamot, citron, and cedra.—Name the constituents of oil
of cloves.—In what respect does otto of roses differ from other oils?—
What class of substances forms the chief part of oil of rue Y—How is cam-
phor-oil related to camphor ?—In what respects do Borneo or Sumatra
camphor and camphor-oil differ from the corresponding products of Japan
and China '—How may Borneo! be artificially prepared ?—How do resins
occurin nature? Distinguish between resins and camphors. Mention
the points of difference of resins, oleoresins, gum-resins and balsams,—
Name the sources of common resin or rosin.—Enumermte some official
articles of which the active constituents are resins.—Give the distinguish-
ing characters of Burgundy pitch.— What is the average proportion of oil
and of resin in the so-called balsam of copaiba?—Explain the effect of
magnesium carbonate, magnesia, and lime on copaiba.—Why do ammonia-
cum, asafetida, gamboge, galbanum, myrrh, and similar substances give
an emulsion by mere trituration with water ?
CARBOHYDRATES.
Under the name carbohydrates there are grouped a large number
of compounds containing carbon with hydrogen and oxygen in the
same proportion asin water. ‘They include sugars, dextrin, sturch,
cellulose, ete. The molecules of some of these are very complex,
but are resolved by hydrolysis into sugars such as glucose,
The most commonly occurring carbohydrates contain six or
multiples of six carbon atoms ; but analogous substances with three,
five, seven, eight, or nine carbon atoms in the molecule are also
known, "
The sugars are among the simplest of the carbohydrates, A
large number of them, some identical with previously known
GLUCOSES 48]
natural sugars, some previously unknown, have been synthesized.
They are partially oxidized polyhydric alcohols, having one of their
alcohol groupings oxidized into an aldehyde or ketone group, For
example, the tribydric alcohol glycerin, on oxidation with bromine
in presence of solution of sodium carbonate, yields g/ycerose, which
has all the characters of a sugar.
H H Hu HH <0
HC—C—CH+ 0=HC—C—X 55+ H,O
0 0 O AQ --
H H H H H
This, however, is not stable, but spontaneously condenses into a
glucose, C,H,,0,.
Erythrose, CJ,O,, is an example of a sugar with four, and
arabinose, C,H,,O,, of one with five, atoms of carbon. Most of the
natural sugars are glucoses (C,H,,0.) or compounds of two or three
molecules of glucose minus water (bioses or frioses),
Sugars with seven, eight, and nine atoms of carbon haye been
constructed by treating glucoses with hydrocyanic acid, which
combines with the aldehyde or ketone group to form the nitrile of
an acid containing ohe more carbon atom. This on hydrolysis
gives the acid, the lactone (see p. 504) of which may be reduced
in acid solution to the corresponding sugar by the action of sodium
amalgam, This process is then repeated to get an eight-carbon
sugar, and soon, One of these seven-carbon sugars was found to
be identical with a natural sugar, perseite, but most of them have
not yet been found occurring naturally,
Glucoses, C,H ,.O
ue
Glucosea, ChH,,0,, There are two chief types of these six-car-
bon sugars, differing from each other in the position of the alcohol
grouping that has undergone oxidation, and classed accordingly as
aldehyde and ketone sugars—a/doses and ketoses. Ordinary glu-
cose, or dextrose is an example of the first class, and /ructoae or
levulose of the second. Each of these classes contains a very large
number of physical isomers, differing from each other in their
action on polarized light and in some other respects ; these may be
most readily distinguished from one another by means of the physi-
cal characters of the compounds they form with phenyl-hydrazine
(see p. 510). The large number of these isomers is accounted for,
on the stereo-chemical theory, by the circumstance that there are
no fewer than four asymmetrical carbon atoms (see p. 306) in each
molecule. Thus there are three dextroses, dextro-rotatory, lsevo-
rotatory, and inactive ; three analogous mannoses ; three fructoses
or levuloses, ete. .
All the glucoses above mentioned have been obtained artificially,
the starting-point being an artificial glucose (aeros, O,H,,0,)
31
482 ORGANIC CHEMISTRY.
obtained by the condensation of formaldehyde—6CH,O0=C <3
it is probably in a similar way that natural sugars are vrodea
lants.
; Glucose (from yAvxic, glucisa, sweet), or Grape-sugar, or Dexr-
frose is often seen in the crystallized state in dried grapes or raisins
and other fruits; the sugar of diabetic urine, also, is one of the
many glucoses. Its crystalline character is quite distinct from
that of cane-sugar, the latter forming short monoclinic prisms,
while grape-sugar occurs in masses of small six-sided plates. Grape-
sugar is also less soluble in water, but more soluble in alcohol than
cane-sugar,
According to Fresenius, the percentage proportion of saccharine
matter in the dried fig is 60 to 70, grape 10 to 20, cherry 11, mul-
berry 9, currant 6, whortleberry 6, strawberry 6, raspberry 4.
Fructose, or Fruit-sugar, or Lrevu/ose is the uncrystallizable, or
very difficultly cerystallizable, constituent of ‘‘inverted’’ cane-
sugar. It is found in the grape, fig (/iews, U. 5, P.), eberry,
gooseberry, strawberry, peach, plum and other fruits, often with
dextrose or with cane-sugar. Fruit-sugar reduces cupric salts and
silver ammonium nitrate. .
Ordinary fructose is levo-rotatory, while sucrose and ordinary
glucose are dextro-rotatory; the latter rotate a ray of polarized
light to the right and the extent of the rotation varies with the
amount of sugar present—a fact easy of application in determining
the amount of sugar present in syrups or in diabetic urine.
Artificial Formation of Grape-sugar from Cane-sugar. Test
for Sugar.— Dissolve a grain or two of cane-sugar in water.
To a portion of this solution placed in a test-tube add more
water, two or three drops of solution of cupric sulphate, a con-
siderable quantity of solution of potassium hydroxide (enough
to turn the color of the liquid from a light to a dark blue),
and heat the mixture to the boiling-point ; no obvious imme-
diate change occurs. To another portion of the sugar solution
add a drop of sulphuric acid, and boil for ten to twenty min-
utes, then add the cupric solution and alkali, and heat as before;
a yellowish-red precipitate of cuprous oxide, Cu,QO, is produced,
This test is exce edingly delicate.
The above reaction is due to the conversion of the cane-sugar,
O,,H,,0,,, imto inverted eugar,' a mixture of glucose and fructose,
‘The name inverted suger originated from the fact that whilea solution
of cane-sugar rotates the plane of polarization of light to the right, the
sense of the rotation is reversed, or “ inverted,” when cane-sugar is hydro-
lyzed into glucose and fructose. Although the glucose so obtained is right-
rotating and is equal in quantity to the fructose, yet the latter pe
left-rotating power to such an extent as to pre ‘dominate over the right-
rotation of the glucose, and a left rotating mixture results.
a
GLUCOSES. 483
by the influence of the sulphuric acid, and to the reducing action
of the glucose and fructose on the cupric solution, The formation
of a precipitate immediately, without the action of acid, shows the
presence of the latter sugars—its formation only after ebullition
with acid indicating, in the absence of starch or dextrin, cane-sugar.
In this reduction-process the sugar is oxidized and broken up into
several substances; but the exact nature of the reaction has not
been ascertained. ;
Dextrin also reduces the cupric salt to cuprous oxide, unless its
solution is cold and very dilute. It does not, however, so act on
a solution of cupric acetate acidified with acetic acid, while glucose
er gag with this liquid the usual red cuprous precipitate (Bar-
oed).
Sugar from Starch.—Boil starch with a smal] quantity of
water and a drop of sulphuric acid as in the preparation of dex-
trin, but continue the ebullition for several minutes ; on testing
a portion of the cooled liquid with iodine, and another portion
with the heated alkaline solution of a cupric salt, as just
described, it will be found that the starch has nearly all hecome
converted into a sugar—glucose, Malose is also formed, at
first, but by the continued action of the acid is changed to glu-
cose. When made on a large scale, a warm (131° F., 51°C. )
mixture of starch and water, of the consistence of cream, is
slowly poured into a boiling solution of one part of sulphuric
acid in one hundred of water, the whole boiled for some time,
the acid neutralized by adding chalk, the mixture filtered, the
liquid evaporated to a thick syrup and set aside; in afew days
it crystallizes to a mass resembling solidified honey. In this
operation a smal] quantity of dextrin remains with the glucose;
hut if the process be conducted under pressure, conversion,
according to Manbré, iscomplete. Sugar made from the starch
of rice, maize, ete., is largely used for table syrups, confection-
ery, bee food, and as a partial substitute for malt in brewing.
It is known as patent sugar, saccharine, maltone, ete.
In the United States the dealers term the syrups ‘‘ glucose,”
and the further evaporated solid product ‘grape sugar."’ The
former contain one-third or more of glucose, about one-fifth of
maltose, one-fourth or more of dextrin, and about one-sixth or
one-fifth of water; the latter often contain about three-fourths of
glucose, from none up to one-third of maltose, and one-seventh or
one-sixth of water.
Galactose (from milk-sugar), Sorbinose (from mountain-ash
berries), Jnosite (from muscle), Mannose (from mannite), (’u/ose,
484 ORGANIC CHEMISTRY.
Formose, B-Acrose, Dambose (from a caoutchouc), and Seyllite
(from many fish) are other glucoses,
Saccharoses, or Bioses, ©,,H,.0,,.
Cane-sugar, or Sucrose (Saccharum, U.8. P.), is a frequent con-
stituent of vegetable juices. Thus it forms the chief portion of
cassia pulp (from Cassia Fistula, U.S. P.), 1s contained in the
carrot and turnip, but is most plentiful in the sugar-cane; much,
however, is now obtained from the sugar-maple and beet-root.
On evaporation of the juice, common brown or moist suger crystal-
lizes out; this by re-solution, filtration through animal charcoal,
evaporation to a highly concentrated syrup, and crystallization in
moulds, yields the compact crystalline conical loaves known in the
trade as /oaf-sugar. These loaves when broken into fragments or
sawn into cubes form /ump- or cube-sugar. From a slightly less
concentrated syrup, slowly cooled, the crystals termed sugar-candy
are deposited, white or colored, according to the color of the
syrup. The official syrup (Syrupus, U. 8. P.), is an aqueous
solution.
The sugar in fresh fruits is mainly cane-sugar; but by the
action of the acid, or possibly of a ferment in the juice, it is
gradually converted into a mixture of glucose and fructose in
varying proportions. Ripe Hips contain 80 percent, of such
sugar, besides gum and acid malates and citrates, Sugar from
flowers, as gathered in the form of syrup by bees, is probably a
mixture of these two varieties. It is gradually altered to a erys-
tulline or granular mass consisting largely of glucose, as seen in
dried fruits, such as Raisins and the Prune (Pruaum, U. 8. P.),
and in solidified Honey. Honey, (Me/, U. 8. P.), often contains
pollen, hairs, spores, the dust from the flowers, and various floc-
culent matters which cause it to ferment and yield mannite, alcohol,
and acetic acid; hence for use in medicine it is desirable that a
process of purification be adopted which yields clarified honey.
Honey and cane-sugar are the bases of the official Confections.
Matltose, C,,H,,0,,.—This crystallizable sugar is formed, together
with dextrin, when diastase or dilute acids act upon starch, Tn
the case of diastase it is the ultimate product, but the dilute meids
nay convert it into glucose. It differs also from glucose im its
optical activity.
Cane-sugar, maltose, and grape-sugar yield alcohol and carbonic
anhydride by fermentation, the cane-sugar and the maltose .
rently undergoing hydrolysis before the production of aleohol
commences,
In bread-making, some of the starch is converted into dextrin,
and this into sugar by the ferment. The above action then goes
on, the liberation of gas producing the rising or swelling of
the mixture of flour, water, and yeast(dough), The temperature
SACCHA ROSES.
to which the mass is subjected in the oven causes the escape of
most of the alcohol, and the expansion of the bubbles of carbonic
anhydride in every part of the now spongy loaf. The carbonic
anhydride gradually evolved when flour is worked up for bread
with a mixture of dry sodium bicarbonate and tartaric acid
(best preserved by previous admixture with dried flour and
a little magnesium carbonate )}—Sating-powder—exerts similar
influence. The least objectionable method of introducing car-
bonic anhydride, however, is that of Dauglish, whose patent
aérated bread is made from flour by admixture with carbonic acid
water under pressure by the aid of machinery. On removal from
the cylinder, the resulting dough expands by the natural elasticity
of the imprisoned carbonic anhydride, and the oven completes
the process, All fermented bread retains, obviously, a little alcohol,
sometimes 0,25 percent,
Action of Alkali on Sugar.—To a solution of grape-sugar
add solution of potassium or sodium hydroxide, or solution of
potassium carbonate, and warm the mixture; the liquid is
darkened in color from amber to brown, according to the
amount of grape-sugar present. A very little picrie acid
greatly intensifies the color.
Tests.—The above, the copper-reaction, and the fermenta-
tion process (p, 420) form three good tests for the presence of
grape-sugar, and, indirectly, of cane-sugar. <A _ piece of
merino or other woolen material, previously dipped in a solu-
tion of stannic chloride and dried, becomes of a brown or
black color when dipped in a solution of glucose and heated
to about 300° F. (about 150° C.) by holding before a fire.
Barley sugar is made by heating cane-augar with water until the
whole is liquefied and then boiling off the added water, a change
from the crystalline to the vitreous condition occurring, with
ahsorption of heat. The greater portion of confectioners’
‘‘aweets’’ are formed of vitreous sugar. They slowly revert to
the crystalline condition, with evolution of heat. Treacle Molasses
or Melasses (from Mel, honey), or Golden Syrup, chiefly results
from the application of too much heat in evaporating the syrups
of the sugar-cane; it isa mixture of cane-sugar with uncrystal-
liable sugar and more or less coloring matter. Licorice-root
| Glyeyrrhiza, U. 8. P.), contains much uncrystallizable sugar.
Caramel—Heat a grain or two of sugar in a teat-tube until it
blackens and froths; the product is caramel, or burnt angar (the
Saccharum Ustum of pharmacy). It is used as a coloring agent
for gravies, confectionery, spirits, vinegar, and similar materials,
It is a mixture of substances, ‘‘ caramels” having slightly
varying properties.
ORGANIC CHEMISTRY.
Milk-sugar, or Lactase, C,H wOwH, O ( Saceharum Lactis,
U.S. P.), the sweet principle of the milk of animals, is not
susceptible of alcoholic fermentation by ordinary yeast ; certain
species of saccharomyces, however, convert it into aleohol, It
resembles grape-sugar in reducing an alkaline cupric solution
with precipitation of cuprous oxide. It is obtained from milk
by adding a few drops of acid, stirring, setting aside for the
curds to separate, filtering, evaporating the whey to a sma)
hulk, filtering again if necessary, and allowing to cool and
erystallize. The deposited crude “ svgar-sand ” is afterward
refined and recrystallized. Thus obtained milk-sugar has the
formula above given, but if deposited from the hot solution
during evaporation, the crystals are anhydrous, C,,A,,0,,.
Milk-sugar is convertible by the action of dilute aci %
(hydrolysis) into galactose and glucose; these may he made
to interact to form milk-sugar. Powdered milk-sugar is used
in pharmacy as a vehicle for potent solid medicines, The
official article is met with in white hard crystalline masses or
as a White powder, odorless, faintly sweet. Soluble in 4.79
parts of water at 25° C., and in 1 part of boiling water. It
should not leaye more than 0,25 pereent. of ash when inein-
erated with free access of air. A limit of ash is necessary as
atest of purity, because magnesium carbonate of oxide, if
added to neutralize the acidity of the whey during evapora-
tion, as is sometimes done, gives rise to the presence of mag-
nesium lactate in the milk-sugar, and this salt being converted
into carbonate or oxide incineration, increases the amount
of ash.
Saecharie Acid, H,C,H.O, or CH,(OH) (COOH), is
the product of the oxidation of suc rose, ‘glucose, starch, gum,
and lignin by nitric acid. Mannose yields meanno-saceharie
acid, isomeric with saccharie acid. Mucic acid, also isomeric
with saecharic acid, may be obtained by the oxidation of lac
tose gum and duleite.
Melitose or Melitriose (from ene alyptus) is a triose, giving on
beasely sis galne tose, glue ‘ose, and fructose, Afelezitose (from the
larch) and Trehalose (from Turk ish manna), belong to the Baccha-
roses. —
‘* Honey-dew"’ is a viseid sace harine matter oce asionally met
with on the leaves of the lime, ms aple, black alder, rose, and other
trees, being a sweet principle exuded from aphides. Sometimes
it is sufficiently abundant to dry and fall on the ground, forming
AMYLOSIS OR AMYLOIDS. 487
a veritable “shower of manna.’’ [tis a mixture of cane-sugar,
inverted sugar, and dextrin.
QUESTIONS AND EXERCISES.
Into what three classes may the carbohydrates be divided? How is
grape-sugar obtained from cane-sugar?—How are cane-sugar and grape-
sugar analytically distinguished ?— How is dextrose obtained from starch?
—Mention the chief sources of cane-sogar.—Give chemical explanations
of the processes of bread-making.—What is thedifference between fruit-
sugar and honey ?—Deseribe the effect of heat on cane-sugar.—How is
milk-sugar obtained, and how does it differ from other sugar ?—How may
mucic and saccharic acids be obtained ?
Amyloses, or Amyloids, nC,H,,O,
_ Starch, nC.H,,O,, is contained in large or small quantities
in nearly every plant. It forms about 60 to 70 percent. of
wheat, and from 20 to 30 percent. of potatoes. The starch
officially recognized in the Pharmacopoeia ( Amylum) is that
of maize (Zea Mays).
Experiment.—Rasp or grate, or scrape with a knife, a por-
tion of a clean raw potato, letting the pulp fall on to a piece
of muslin placed over a small dish or test-glass, and then pour
a slow stream of water over the pulp; minute particles or
granules pass through the muslin and sink to the bottom of
the vessel, fibrous matter remaining on the sieve. The gran-
ules consist of potato starch. Even diseased potatoes furnish
good starch by this method. Wheat-starch may be obtained
by tying up some flour in a piece of calico, and kneading the
bag in a slow stream of water flowing from a tap, the wash-
ings running into a deep vessel, at the bottom of which the
starch collects; the sticky matter remaining in the bag is
gluten.
The blue starch of the shops is artificially colored with smalt or
indigo, to neutralize the yellow tint of recently washed linen; it
should not be used for medicinal purposes. Starch dried in mass
splits up into the familiar columnar masses in which the commer-
cial article is met with.
Gluten is the substance which gives tenacity to dough and bread.
It seems to be a mixture of vegetable fibrin, vegetable casein, and
an albuminous matter termed glutin. Each of these bodies con-
tains about 16 percent, of nitrogen. In the anhydrous condition
gluten consiats of carbon 52.6 percent,, hydrogen 7 percent., nitro-
488 ORGANIC CHEMISTRY,
gen 16 percent., and oxygen, with a trace of sulphur, 24.4 per-
cent. Wheaten Flour contains about 72 percent. of ‘starch and
11 of gluten, as well as sugar, gum, fine bran, water, and ash.
The compactness of barley, well seen in Musked or Pearl B
is said to be due to the large amount of vegetable fibrin present.
During germination the fibrin is destroyed ; hence, probably, the
eretaceous character of malt, Oatmea/, popular when made into
‘‘porridge,’’ is rich in albuminoids, or flesh-forming constituents,
containing nearly 16 percent, Sago is granulated starch from the
Sago Palm ; fapioca from the Bitter Cassava ; each has less than
1 percent. of albuminoids. The white translucent /tice grains are
the husked seeds of Oryza sativa. Rice is a staple article of food im
tropical countries. Ground rice (Oryze Farina), resembles flour
of wheat in composition, but contains from 85 to 90 percent, of
starch.
Mucilage of Starch.—Mix two or three grains of starch
with first a little and then more water, and heat to the boil-
ing point ; starch mucilage results. This mucilage or paste is
not a true solution; by long boiling, however, a portion
the starch becomes ‘dissolved. In the latter case the starch
probably becomes somewhat altered.
Test.—To some of the mucilage add a very little free iodine; a
deep-blue color is produced. This reaction is a very delicate test
for the presence of either iodine or starch. The starch must be
in the state of mucilage ; hence in testing for starch the substance
supposed to contain it must first be boiled with water, The solu-
tions used in the reaction should also be cold, or nearly so, as the
blue color disappears on heating, although it is ' partially restored on
cooling. The iodine reagent may be iodine-water or tincture of
iodine. In testing for iodine, its occurrence in the free state must
be ensured by acidulation if necessary, and the addition of a drop,
or even less, of chlorine-water. Excess of chlorine must
avoided, or iodic acid will be formed, which does not color starch,
The so-called iodide af starch scarcely merits the name of a
chemical compound, the state of union of its pee being
so feeble that it is decomposed at 100° F. (37.7° C.), while sub-
stances which attack free iodine remove me element from it,
Thus the alkalies, hydrogen sulphide, sulphurous acid and other
reducing agents, destroy the blue color. Dry starch will absorb,
according to its source, from 6 to 8 percent. of iodine ; but in the
state of mucilage three times the quantity. There are Rabie
three definite compounds of starch with iodine, With nitric
starch yields an explosive compound (Xyloidin) C,,H,,0 (NO,),
Two isomeric tetranitro-derivatives, us well as a penta- and a hex-
anitro-derivative, are known.
STARCH. | 489
Composition of Starch Granules, —Starch granules consist mainly
of granulose, soluble in cold water and giving an indigo color with
iodine, and sfarch cellulose, insoluble in water and giving with
iodine a dirty yellow color, with, possibly, other carbohydrates,
The starch cellulose forms an external coating upon the granule,
and also exists mixed with the granulose inside the granule. If
this coating be broken by mechanical means, the continued appli-
cation of cold water removes all the granulose, leaving the cellu-
lose insoluble. By the action of diastase, ptyalin, and other fer-
ments, and by other means, the granulose may be converted into
sugar and dextrin, leaving the starch cellulose unacted upon,
Microscopie Examination of Starches.
All kinds of starch afford the blue color with iodine, showing
their chemical similarity. Physically, however, the granules of
different starches differ from each other; hence a careful micro-
scopic examination of any starch, or of any powder or vegetable
tissue Containing starch, enables the observer to state, with a high
degree of probability, the source of the starch, either at once if
he has much experience, or after comparing the granules in ques-
tion with authentic specimens, (A glance at the accompanying
eight engravings' of common starches will show to what extent
different starch granules differ naturally in size, shape, general
appearance, distinctness and character of the ruge, and position
of the more or less central point of Ai/em). While from different
starches individual granules may be picked out which much resem-
ble each other, the appearance of each starch as a whole is fairly
characteristic; that is to say, each group of granules differs in one
or more characters from similar growps of granules of other starches,
A quarter-inch object-glass will commonly suffice for the micro-
scopic examination of starch. A very little of the starch is mixed
on a glass slide with a drop of water, and a piece of thin covering
glass placed on the drop and gently pressed, so as to provide a
very thin layer for observation. Instead of water, diluted aleohol,
diluted glycerin, turpentine or other essential oil, Canada balsam,
and other fluids may be used in cases where the markings or
other appearances are not well defined. The illumination also of
the granules may be varied, the light being reflected or trans-
mitted, concentrated or diffused, white or colored, polarized or
plain. Polarized light is especially valuable in developing differ-
ences, and in intensifying the effects of obscure markings. By
polarized light the granules of potato starch appear as if trav-
ersed by a black cross; wheat starch granules and many others
also peculiarly and characteristically influence polarized light.
Distinctive characters will sometimes present themselves only
' By permission of Messrs, Longmans & Co., these engravings have
been copied, with very few modifications, from the plates in two of the
three volumes of the original edition of Pereira’s ' Materia Medica,”
490 ORGANIC CHEMISTRY.
STARCHES,
(Magnified 250 diameters.)
re. inch=-+ — —- sigs. 42 to. 49,
(ee rent Gane .
2 z weitere me =a - oe ee 1
; e) aes i a" Ss
Bee... SO. @GSe Em
| 7 fy 2a . = a" a ) —/ =< - Z ‘ae ‘ - ; |
a a oO aay of bet | 4 = iL TT Ea stan
* yw + ee — i
- = ‘A
& BS is
oe:
POR ey
MAIZE (zea) |
an | 7
my | | lela 3 ,
Hie s \ : re, a
: D ff... = ek os ee’ }
rs ep 0 :
4 "%,
’
1 4 =
Le 4
. Bsa a
INULIN, 491
when the granules are made to roll over inthe fluid in which they
have been temporarily mounted, or when the slide is gently
warmed, Starches which have already been subjected to the in-
fluence of heat, partly, as in sago or tapioca, or almost entirely, us
in bread, will of course differ in appearance from granules of the
same starch before being dried, cooked, or torrefied. The char-
acters of a starch will also vary somewhat according to the age
and condition of the plant yielding it,
The description of the microscopic characters of some varieties
of starch' is as follows :—1. Wheat starch: A mixture of large
and small granules, the former lenticular in shape, and marked
with faint concentric stri# surrounding a nearly central hilum.
2. Maize starch ; Granules more uniform in size, frequently polyg-
onal, somewhat smaller than the large granules of wheat starch,
and having a very distinct hilum but no evident concentric strim.
3. Rice starch; Granules extremely minute, nearly uniform in
size, polygonal, and without evident hilum or stri«,
The student may place fair confidence in the accompanying
illustrations, and in most of the published engravings of starch
granules ; but in microscopic analyses of importance the worker
should, if possible, himself obtain actual specimens of starches
for comparison from the respective seeds, fruits, and other tissues.
Inulin, 6C,H,,O,, H,O (Kiliani), oceurs with similar substances,
preudo-inulin, 16C "H,,O,,H, O, and inulenin, 10C,1,,0,, 2H 0
(Tanret). It isa white powder apparently occupying the ‘place of
starch in the roots of many plants, especially those of the natural
order Composite, Twenty to forty-five percent, has been obtained
from eclecampane (Jnula helenium), It is also contained in the
dahlia, colchicum, arnica, dandelion, chicory, artichoke, ete, It
is soluble in boiling water, nearly all being re-deposited on ecoal-
ing, Todine turns it yellow. Long ebullition converts it into a
kind of gum. Like starch, inulin is convertible into sugar, but
by its own special ferment, the existence of which in the Jeru-
salem Artichoke has been demonstrated by J. R. Green. This
ferment differs from diastase in being without the power of con-
verting starch into sugar,
Lichenin, aC, H,,0,, is a white starch-like powder largely con-
tained in many ‘Tichens—Iceland “ Moss,’’ Cefraria Islandica, and
many others. It is soluble in boiling water, and the fluid gelatin-
izes on cooling. It may be precipitated from its aqueous solution
by addition of alcohol. With iodine it gives a reddish-blue color,
Glycogen, or animal starch, is the name given to the solid matter
' For plates and descriptions of the characters of other starches occur-
ring in plants used for medicinal purposes, the reader is referred to works
on Materia Medica, and to the indexes of Journals of Pharmacy, as well
as to general works and magazines on microscopy. F or ¢ neravings of
starch granules in sifu, see Borg’s “Anatomisacher Atias,’’ published by
(iacrtner, Berlin.
492 ORGANIC CHEMISTRY.
stored in the liver and resulting from the dehydration of the
digested hydrated food which has been carried to the liver by the
portal vein.
Dextrin, nCH,,0,.—Mix a few grains of starch with half
a test-tubeful of cold water and a drop or two of sulphurie
acid, and boil for a few minutes ; no thick mucilage is formed,
and the liquid, if sufficiently boiled, yields, on cooling, no blae
color with iodine ; the starch has become conyerted into dex-
frin and sugar. Dextrin is also produced if starch is main-
tained at a temperature of about 320° F. (160° C.) fora
short time. Dextrin is largely manufactured in the latter
way, and a paste of it is used by calico printers as a vehicle
for colors; it is termed British qun. The change may also
be effected by dias/ase, a peculiar ferment existing in malt.
Mix two equal quantities of starch with equal amounts of
water, adding to one a little ground malt, then heat both
slowly to the boiling-point ; the mixture without malt thickens
to a paste; that with malt remains thin, its starch haying be-
come converted into dextrin and maltose.
Diastase is probably a mixture, but possibly an oxidation prod
uct, of the coagulable albuminoids, It is 80 named from désieracic
(diastasis) separation, in allusion to the separation, or rather altera-
tion, it effects among the constituent atoms of the molecule of
starch, This function is shared by the saliva, pancreatic juice,
bile, and the intestinal and other juices. The function is com-
pletely destroyed when the albuminoids are coagulated by a tem-
perature of from 176° to 178° I, (80° to 81° C.),
The Action of Diastase upon Starch.—Diastase has searcely any
action upon unbroken starch granules, The granules must be
ruptured by gelatinization with heat and moisture, or in some
other way. When a solution containing diastase, such as a cold
water infusion of malt, is allowed to act upon gelatinous starch or
starch-paste at 140° to 160° F. (60° to 71° C.), liquefaction occurs.
It is possible to operate so that when liquefaction has taken re
the solution shall give no reaction for sugar or dextrin, this
solution be concentrated and allowed to cool, a glistening white
precipitate of soluble starch falls. Soluble starch is probably the
result of the partial decomposition of the more complex molecule
of granulose or gelatine mus starch. The next step in the action of
diastase upon gelatinous starch is the breaking down of the solu-
ble starch molecule into dextrin and maltose. At least ten dex-
trins are successively produced, each simpler than the one preced-
ing it, the proportion of maltose being correspondingly increased.
The dextrins first produced give a red or brown color with iodine,
MALT. 493
while those last produced, and having a simpler molecule, give no
color with iodine. The final reaction may be expressed thus :—
0) O > = &C,,H,,0 4(C,H,,O
ae eo Mas Sale
The dextrins are distinguished by their rotatory power, their reduc-
ing action on cupaic salts, and in other ways. |
Starch heated with glycerin is converted into the soluble variety.
The latter may be precipitated from an aqueons solution by strong
alcohol. A concentrated solution in water gradually gelatinizes,
owing to reconversion into insoluble starch (Zulkowsky).
The Action of Dilute Acids upon Starch.—Dilute acids act upon
gelatinous starch in the same way as diastase, except that the final
product is glucose, .
Malt (Maltum, U. 8. P.), (the word malt is said to be derived
from Welsh mai/, soft or ‘‘rotten’’) is simply barley which has been
softened by steeping in water, and allowed to germinate slightly,
any further change being then arrested by the application of heat
inakiln, During germination the gluten breaks up and yieldsa
glutinous substance termed vegetable gelatin, diastase, and other
matters. To the vegetable gelatin is due much of the * body”’ of
well-malted and slightly-hopped beer ; it is precipitated by tannic
acid ; hence the thinness of ale (pale or bitter) brewed with a large
proportion of hops or other material containing tannic acid. <A
portion of the diastase reacting on the starch of the barley con-
verts it into dextrin, and, indeed, carries conversion to the further
stage of maltose, as will be explained immediately. The tempera-
ture to which the malt is heated is made to vary, so that the sugar
of the malt may or may not be partially altered to a dark-brown
coloring material ; if the temperature is high, the malt is said to
be high-dried, and is used in porter-brewing ; if low, the product
is of lighter color, and is used for ale, The diastase remaining in
malt is still capable of converting a large quantity of starch into
dextrin and maltose; hence the makers or distillers of the various
spirits operate on a mixture of malted and unmalted grain in pre-
paring liquors for fermentation,
Extract of Malt (Extractum Malti, U.8. P.), is an evaporated
infusion of malt. Taken with food, its diastase aida in the con-
version of starch into maltose and dextrin, and, pro tanto, assists
enfeebled digestive powers.
$C,H,0, + H,O = GC,
Stare
H,.O,, + 0,H,,0,
Maltase Dextrin
As diastase begins to lose this power at temperatures above 150°
F. (55,5° ©,), that limit should not be exceeded in evaporating
the infusion ; indeed, if the dissolved albuminoid matters are to
be retained, the evaporation should be conducted at 120° F,
(18.8° C,),
494 ORGANIC CHEMISTRY,
The following method serves for the determination of the
diastasic power of malt extract :—1.5 grammes of extract are
dissolved in 15 Ce, of water and mixed with a mucilage of
0.1 gramme of starch in 100 Ce. of water. The mixture is
raised to 140° F, (60° C.) and tested from time to time hy
adding two drops of iodine solution to 5 Ce, of it, and com-
paring with } Ce. of a similar mixture to which no starch has
been added. If the two solutions do not exhibit any differ-
ence of tint this indicates the completion of the reaction,
Good malt extract will accomplish this within half an hour,
some samples will take less time, but many commercial
extracts will require three hours or more.
Gum is a frequent constituent of vegetable juices, existing in
large quantity in several species of Acacia, The nature of gums
is very little known, though most probably they all belong to the
carbohydrates. According to Fremy, gum contains a calcium
salt (sometimes also a potassium salt) of the gummie or arabie
radical, though consisting mostly of arabin or arabic acid alone.
The formula of gummic acid is said to be H,C,,H,,0,,,H,0, but
from the important researches of O'Sullivan, it would seem to be
far more complex, a multiple of the empirical formula C,H,,0.—
according to Raoult (C,H,,O,),. Gum differs from dextrin in
yielding mucic acid when oxidized by nitric acid. Good adhesive
mucilages may be made from such gum-arabic substitutes as
‘(rhatti,’’ ‘“amrad,’’ ete. Jndian Gum is an exudation from the
wood of Anogeissus latifolia. It has double the mucilaginous
strength of Gum Acacia (Acacia, U. 8. P.). Cerasin or cherry-
tree gum is calcium metagummate, an insoluble modification of
acacia gum. Basxorin, traganthin, or adraganthin, C,H, Oy, is a
form of gum which is insoluble in water, hut absorbs large quanti-
ties of that liquid and forms a jelly-like mass; it occurs largely
in Tragacanth, combined, like arabin, with calcium. Peefin, or
Vegetable Jelly, C,H,O,,, 4H,O, is the body which gives to
expressed vegetable juices the property of gelatinizing: it forms
the chief constituent of Irish or Carrageen ‘* Moss’’ (Chondrus,
U, SB. PL.) | Ceylon ‘ Moss’’ contains from one-third to three-
fourths of vegetable jelly. Many seaweeds yield a jelly when a
decoction of them is cooled, The Japanese freeze the jelly of
Gelidium corneum and then cut it into strips; these slowly dried
form the so-called Japanese tainglass, Chinese Moss, or gelose of
Payen. It is probably a carbohydrate. With water, it Is said
to give a jelly 10 times stronger than that obtained from gelatin.
The mucilage of marsh-mallow root (Althea, U. 8. P.), and of
linseed or common flax-seed (Linwm, U.S. P.), is a gum-like sub-
stance containing much mineral matter, It is the basis of the
Infusions termed mallow-tea and linseed-lea. Somewhat similar
DINITROCELLULIN. 495
mucilage occurs in Bael Fruit, the fresh half-ripe fruit of gle
Marmelos. It is also largely yielded by the a of the Quince
(Pyrua Cydonia). Salep, the powdered dried tubers of many
species of Orchis, contains a large quantity of such matter, as also
does Squill, The Indian Ora and Jspaghul or Spogel seeds also
appear to contain « considerable quantity.
— Cellulin, or cellulose, wC,H,,O,, the woody fibre of plants, famil-
jar, in the nearly pure state, under the forms of ‘ cotton wool ’’
(Gossypium Purificatum, U.S. P.), hairs of the seed of various
species of Gossypium), paper, linen, and pith, is another substance
isomeric, probably polymeric, with starch. Lignin is a closely
allied body, lining the interior of the woody cells and vessels of
plants. By the action of nitric acid of various degrees of concen-
tration on cellulin, di-, or tri-nitrocellulins, and possibly others,
ere readily formed :—nC,H,O,(NO,), ; #C,H,O,(NO,);. _ Trinitro-
cellulin is highly explosive gun-cotton ; dinitrocellulin is not
sufficiently explosive for use instead of gunpowder. | Mononitro-
cellulin has not been so thoroughly examined as the others, but is
said to be scarcely at all explosive ; its formula is nC,H,O,NO,.
The heat of a water-bath may explode trinitrocellulin, but not
dinitrocellulin if pure. The three displaceable hydroxyl groups
ee Seta may be displaced by groups other than the nitric
radical.
Dinitrocellulin (Pyroxylinum, U.S. P.), may he prepared
by the following official process :—Mix 5 fluid ounces of sul-
phurie acid and 5 of nitric in a porcelain mortar, immerse 1
ounce of cotton-wool in the mixture, and stir it for three min-
utes with a glass rod, so that it is thoroughly and uniformly
wetted by the acids. Transfer the cotton to a vessel contuin-
ing a considerable volume of water, stir it rapidly and well
with a glass rod, decant the liquid, pour more water upon the
mass, agitate again, and repeat the affusion, agitation, and
decantation until the washings no longer give a precipitate
with barium chloride. Drain the product on filter-paper, and
dry on a water-bath.
Pyroxylin may also be made by soaking 7 parts of white filter-
paper, which bas been washed in hydrochloric acid and dried, in
a mixture of 140 parts of sulphuric acid (sp. gr. 1.82) and 70 of
nitric acid (1,387) for three hours, and well washing the product
(Guichard).
Trinitrocellulin or gun-cotton is insoluble ina mixture of aleo-
hol and ether; dinitrocellulin or pyroxylin is soluble, the solution
forming ordinary collodion (Collodium, U. 8. P.). The official
proportions are 40 grammes of pyroxylin dissolved in a mixture
of 750 Ce. of ether and 250 Ce, of alcohol, After digesting for a
—————<<=——it
496 ORGANIC CHEMISTRY.
few days, decant the liquid from any sediment and preserve it in
a well-corked bottle. It dries rapidly upon exposure to air, and
leaves a thin transparent film, insoluble in water or alcohol.
Flexible collodion | Collodium Flexible, U. 8. P.), is a mixture of
collodion (92 parts), Canada Turpentine (5 parts), and castor oil
(8 parts). Cantharidal Collodion (Collodium Ca idatun
U. 8. P.), is a solution of the active blistering principle of can-
tharides in flexible collodion, Many articles of utility and beauty
ure now made of pyroxylin variously colored and sold under the
name of wylonite (cbAov, rulon, wood) or celluloid,
Tunicin, or animal cellulose, exists in the mantle of Asecidia,
QUESTIONS AND EXERCISES.
How is wheat-starch or potato-starch isolated ?—Define gluten and glu-
tin.—Enumerate the proximate principles of wheaten flour.—Is
soluble in water?—Which is the best chemical test for starch ?—Distin-
guish physically between the varieties of starch.—Into what compound is
starch converted by heat?—What occurs when a mixture of starch and
water is allowed to flow into hot dilute sulphuric acid ?—Deseribe the
different results of heating starch with water alone, and with water and
a small quantity of ground malt.—Write a short article on the ¢ i
of malting.—W hat is the nature of gum arabic, and how is it distingnished
from “ British gum’? ?—Mention the properties of the products of the
action of nitric acid of various degrees of concentration on cellulin.—How
is pyroxylin prepared ?
GLUCOSIDES.
Source.—The glucosides are certain vegetable principles which,
by ebullition with dilute acid, or by other treatment, take up the
elements of water (i.¢., undergo hydrolysis) and yield glucose,
accompanied by a second substance, which differs in each case
according to the glucoside operated on. Some of the glucosides
may be regenerated from the substances into which they are eon-
verted by hydrolysis. Tannin, which has already been described
among the acids, is held by some authorities to be a glucoside.
Note on Nomenclature.—The first portion of the names of glu-
cosides and neutral principles generally is commonly given in
allusion to origin ; the last syllable is in.
The following paragraphs deal with the glucosides and with a
few other non-alkaloidal vegetable principles which are of pharma-
ceutical interest and importance,
ABSINTHIN, C,,H,,O,, the bitter principle of Artemisia Absin-
thium, or wormwood, yields, when boiled with acids, glucose,
volatile oil and « resin of the aromatic series. (The liquor
termed absinthe is ethyl alcohol (of varying strength) favored with
natural oil of wormwood, colored by chlorophyll, and slightly
sweetened. )
GLUCOSIDES. 497
AMYGDALIN, C,,H,,NO,,3H,0. This substance, obtained by
Robiquet and Boutron-Charlard in 1830, was the first discovered
glucoside (Liebig and Wéhler, 1537). It is a white crystalline
substance, existing in the bitter almond (Amygdala Amara,
o. 82. ), but not in the sweet (Amygdela Duleis, U.S. P.),
About 2 percent. is readily extracted by strong alcohol from the
cake left when the fixed oil has been expressed from bitter
almonds, From the concentrated alcoholic solution ether precip-
itates the amygdalin.
Experiment.—Make an emulsion of two or three sweet
almonds by bruising and rubbing them with water, and notice
that it has no odor of essential oil of bitter almonds ; add a grain
or two of amygdalin: an odor of essential oil of bitter almonds
is at once developed. Bruise two or three bitter almonds and
rub with water: the volatile oil is again developed.
The source of the benzaldehyde, or essential oil of bitter almonds,
in these reactions, is the amygdalin, which, under the influence
of aynaptase or emulsin (a nitrogenous, casein-like ferment existing
in bitter and sweet almonds), splits up into benzaldehyde, hydro-
eyanie acid, and glucose :—
C,H,NO, + 2H,O = C,H,COH + HCN + 20,H,,0,
Amnygdalin Water Benzaldehyde Hydro- Clacose
cyanic acid
As each molecule of amygdalin yields one of hydrocyanie acid, a
simple calculation shows that 17 grains ae with emulsion of
sweet almonds, Eymulsum Amygdala, U, 8, P.), will be required to
form one grainof hydrocyanic acid. The hydrocyanic acid is prob-
ably i in chemical combination with the oil, to the extent of about
5 percent. According to Lindo, the production of the benzalde-
hvde is preceded by the formation of benzaldehyde-cyanhydrin,
C. ~H,CH(OH)CN. The emulsion and amygdalin occur in different
parts of the bitter almond. Agua A mygdaler Amare, U. 8. P., is
made from the essential oil, which therefore is also included in the
U, &.P.
Test. —The reaction between synaptase and amygdalin is appli-
cable as a test for the presence of one by the addition of the other,
even when mixed with much organic matter.
When amygdalin is warmed with fuming hydrochloric acid,
mandelic, or phenylglycollic acid, C,H, .CHOH.COOH, is pro-
duced,
Cherry Laurel Water, prepared by distillation with water from
Laurocerasit Folia contains hydrocyanic acid derived from a reaction
similar to, indeed probably identical with, that described above,
for bitter almond oil is simultaneously produced. But the pro-
portion ofamygdalin or analogous substance in cherry-laure] leaves
32 .
498 ORGANIC CHEMISTRY.
is most variable; hence the quantity of hydrocyanic acid in the
gael is variable,
ields a glucoside, /inamarin, related to amygdalin, for
it affords nest Lar and hydrocyanic acid on hydrolysis.
Prunus Virginiana,—This, the recently dried burk of Prunus
serotina, furnishes by distillation an essential oil and ee
acid as also do the seeds of the Quince (Pyrus Cpe aes “ild
Black Cherry, collected in autumn, contains am
Caution. —Essential oil of almonds is of course Was salem
The purified oil or benzaldehyde is almost innocuous ; it is obtained
on distilling the crude oi] with milk of lime and ferrous chloride,
and drying the product by shaking with fused calcium chloride.
The so-called ‘artificial oil of bitter almonds’ or nitrobenzene,
C,H,NO,, when taken in quantity, has been known to
death, ‘The presence of nitrobenzene i in oil of bitter almonds is
detected by adding a little of the oil to a mixture of zine and dilute
sulphuric acid, shaking well, setting aside for an hour or two,
filtering off the clear liquid, which now contains phenylamine, or
aniline, and adding some potassium chlorate; a violet color is pro-
duced, ‘due to the oxidation of the aniline with formation of ani-
line mauve (see p. 555), Or the specimen may be shaken with
sodium bisulphite to fix the benzaldehyde (for all such aldel
form a compound with sodium bisulphite), and then with et
which dissolves out, and on evaporation will yield, the nitroben-
zene,
ArsuTin, C,,H,,0,, and methyl-arbutin, C wH, ,O,, are contained
in the leaves of Arctostaphylos Uva Urai, Chimaphila umbellata
(Chimaphila, U. 8. P.), and many ericaceons plants. Arbutin is
a neutral substance oceurring * or crystals, and resolvable
by acids into hydroquinone, C.H and glucose, and by
oxidation into quinone, C H, O., sade formic acid. Ericolin, C,,
is another bitter glucoside ¢ in bear-berry leaves,
Caruartic Actp.—The name cathartic acid was given by
Dragendorff and Kubly to the glucoside-acid to which the the pg
tive properties of Alexandria and India Senna (Senna, U
appear to be chiefly due. Genz states that the formula fir tbe
acid is C|H,.NO,,. The acid itself, which is obtained in the form
of a black m mass, "ts described as insoluble in water, alcohol, and
ether, while its alkali- metal and other salts which occur in senna
are readily soluble, Dilute alkalies dissolve it, yielding solutions
from which it is reprecipitated on adding an acid, Its ammonium
salts give brownish flocculent precipitates with salts of silver, ti
mercury, copper, and lead. When boiled with dilute
cathartic acid undergoes hydrolysis, yielding cathartogenie
and glucose,
Buckthorn Juice (Pluidextractum Frangale, U. 8, P. ), Owes its
cathartic properties to a substance apparently identical with
cathartic acid,
GLUCOSIDES, 499
CoLocynTHIN, C,,H,,0,,—This substance is the active bitter
and purgative principle of colocynth-fruit (Co/oeynthia, U. 8. P.);
it is soluble in water and alcohol, but notin ether. By ebullition
with acids it furnishes glucose and a resined substance.
CONVOLVULIN, —See JALAPIN,.
Corory, C,,H,,0, appears to be the chief active principle of
Coto bark, a Bolivian remedy for diarrhea, A similar bark, false
colo, or paracoto, contains paracotoin, C,,H,O,, and hydrocotoin,
Cult ners : ‘ ;
APHNIN, C,,H,,0,, is the crystalline glucoside of the bark of
Daphne Mezereum (Mezereum,U. 8. P.). Boiled with dilute acids,
it yields daphnetin, C,H,O,, and glucose, The acrid principle of
mezereum is resinoid '
Di@rraLin, C,H,O,, Schmiedeberg ; C,H,,O,,, Kiliani,—This
is an active principle of the Foxglove, Digitalis purpurea. Three
different glucosides have been prepared from the leaves and seeds
of digitalis :—digitalin, digitonin, and digitoxin (digitoxin oceur-
ring in the leayes only), The preparation known as commercial
digitalin has been shown to consist of mixtures containing more
than one of these glucosides.
The process for the preparation of commercial digitalin consists in
extracting digitalis-leaves (Digita/ia, U.S. P.), with alcohol, distil-
ling off the alcohol, dissolving the residue in water containing a
small quantity of acetic acid, removing much of the color from the
solution by means of animal charcoal, neutralizing most of the
acetic acid with ammonia, precipitating the glucosides by adding
tannic acid (with which they form insoluble compounds), washing
the precipitate, rubbing and heating it with alcohol and lead oxide
(which removes the acid as insoluble lead tannate), again decolori-
zing by means of animal charcoal, evaporating to dryness, washing
out with ether any impurities still remaining, and drying the resi-
due. The product is uncrystallizable and somewhat indefinite.
Pure digitalin is prepared from commercial digitalin by dis-
solving the latter in 4 times its weight of 95 percent. alcohol, add-
ing 5 times its weight of ether, separating the liquid from undis-
solved matter and evaporating it in vacuo to about two-thirds of
its volume, adding water, filtering off and washing the precipitated
crude digitalin, and then recrystallizing this from 95 percent. aleo-
hol. The pure product is colorless and granular, but it can also
be obtained in needle-shaped crystals. It is sparingly soluble in
water, ether, and chloroform, but easily soluble in alcohol. When
moistened with sulphuric acid and exposed to the vapor of bromine,
a violet color is produced. On hydrolysis digitalin yields digita/i-
genin, C,,H,,0, ; digitalose, C/H,,0,, and glucose.
Pigitonin, C,H,O,,.—This glucoside, which does not possess
the physiological action characteristic of digitalis, is closely allied
to saponin, It yields on hydrolysis digifogenin, C,,H,,O,, galac-
toxe, and glucose. |
500 ORGANIC CHEMISTRY,
‘“ Divitaline erystallisée,’'—On treating commercial digitalin
with chloroform an inert substance remains undissolyed. The solu-
tion yields on evaporation a substance known in France as digi-
taline crystallisée which is apparently identical with digitoxin 5 it
may be crystallized from alcohol in radiating needles (Nativelle),
The therapeutic effect of this substance is identical with that of
the preparations of digitalis, but more constant in its action, and,
of course, saga | powerful.
Digitorin, Cy,H,,0,,, 1s the highly poisonous Sgr of digi-
talis leaves. it t yields on hydrolysis digitorigenin, C,,H,,O,, and
digitoxose, C,H,,.O,.
ELATERIN, ( «oH,,0,.—Boil elaterium, the dried sediment from
the juice of the squirting-cucumber fruit, with chloroform, filter,
evaporate, wash the precipitated elaterin with ether, recrystallize
it from chloroform and again wash the crystals with ether. The
product, (/aterinum, U.S. P.), occurs in small hexagonal plates or
prisms.
Elaterin is probably not a true glucoside. It does not always
respond to the test for glucose after boiling with acids ; and when
it does, the reaction is possibly due to prophetin, a glucoside stated
by Walz to be present in elaterium.
Elaterin is the active principle of the so-called elaterium,
Elaterium occurs in light friable greenish-grey cakes. Good
specimens of this drug should yield not less than 20 percent, of
elaterin by the above process.
Test. —Elaterin is placed in a watch-glass with a drop of liquefied
carbonic acid, and then two drops of concentrated sulphuric acid;
a carmine color is developed (Lindo).
FRANGULIN, C,H,,0,, is a glucoside found in the bark of
Rhamnus frangula (Frangula, U.S. P.). On hydrolysis it yields
emodin, C,.H,,O,, and an unfermentable sugar, rhamnose, CH,,O,.
GENTIOPICRIN or G ENTIAN-BITTER, C,,H,,O,,, the neutral crys-
talline principle of the root of Gentiana lutea (Gentiana, U. 8. P.).
It is soluble in water and dilute alcohol. Alkalies decompose it.
Dilute acids convert it into gentiogenin and glucose. Gentian
root also contains a variety of tannin and crystalline acid,
HC, ,H,0,, termed gentianic, or gentisie acid, or gentisin. Fused
pots issium hy droxide, ete.,. give with the latter an acid (CLH,0,),
whie h has also, unfortunately, | been called gentisic acid,
GLYC ‘YRRHIZIN or G slyeyrrhizie Acid, C ,,U,,0,, Gorup-Besanez;
0 HNO he Habermann.- hi icorice-root (Glycyrrhiza, U. 8, P.),
in ‘addition to une crystallizable sugar contains 8 or 4 percent. of a
sweet substance, glycyrrhiz in, which, when boiled with hydro-
chlorie acid or dil lute Lac yanaeyteerses yields a resinoid bitter sub-
atance, glye yrr etin, and an uneryst srystal alli zable sugar ee Tee
cose, Glycy erhisin is preeent in rirae dum Glycyrrhiza, U
Fluide rtractum Gye. yrrhiz mo, U.S.P., andin the evaporated decoc-
tion (Stick Li icorice, 'Spanish Livoric e, or Solazzi Juice), Itis soluble
GLUCOSIDES. 501
in ammoniacal water. The tropical substitute for licorice is the root
of Abrus precatoriua or Indian Licorice, the kunch or quny of Bengal,
the raéfi of Hindustan, and the jequirity or jaquerity of Brazil,
which also contains glucose and glycyrrhizin. The seeds yield
by maceration a substance which acts as a poison when injected
into the blood, but not when swallowed. Warden and Waddell
regard the active principle as an albuminoid and term it abrin.
Bruylants and Venneman consider it to be a product of germina-
tion, and eall it jeguerifin. Bechamp and Dujardin regard the
latter as a mixture of legumin and jequerityzymase. Glycyrrhizin
has considerable power of disguising nauseous flavors, Roussin
refers the sweet taste of licorice not to pure glycyrrhizin but to a
combination of glycyrrhizin with alkalies, and states that ammo-
niacal glycyrrhizin has exactly the sweetness of licorice-root. The
formula of this ammonium glycyrrhizate is said by Habermann to
be (NH,),C,,H.NO,,. Sestini finds that the glycyrrhizin of licorice-
root is chiefly calcium glycyrrhizate.
GUATACIN.—Resin of guaiacum (Guaiaewm, U. 8. P.), an exuda-
tion from the wood of Guaiacum officinale, is probably a mixture
of several substances, among which are guaiaretic or guaiaretinic
acid, C,,H,.O, (Hlasiwetz), guaiaconic acid, C,,H,,O,, and guaiacin,
a glucoside. On boiling guaiacum resin with dilute sulphuric
acid for some time, glucose is found in the liquid, a green resinous
substance (guaiaretin) remaining insoluble (Kosmann), Most
oxidizing agents, and even atmospheric air, especially under the
influence of certain organic substances, produce a blue, then
green, and finally a brown color when brought into contact with
an alcoholic solution of guaiacum resin. Ferrie chloride is the
official test for this purpose. These effects are said to be due to
three stages of oxidation (Jonas), They may be observed on
adding the solution to the inner surface of a paring of a raw potato,
HELLesoriy, C,.H,,0,, and HELLEBOREIN, C,H,,0,,, are crys-
talline glucosides occurring in the roots of Black Hellebore ( Helle-
borua myer), or Christmas rose, and Green Hellebore (/f, viridis),
ranunculaceous herbs. The former is insoluble in water, but
soluble in ether; the latter soluble in water, but insoluble in ether,
JALAPtIN, C,,H,,O,, or C,H, 0.) and CONVOLVULIN, O, 110,
—Some confusion exists regarding the names of these substances,
The glucoside originally known as jalapin is now almost uniformly
called conyolvulin in Germany, while the German jalapin, which
appears to be identical with scammonin, is not infrequently called
convolvulin. According to Kayser and Mayer, jalap-resin con-
tains two distinct substances—convolvulin, chiefly obtained from
Mexican male jalap (Jpomea Orizabensis), and jalapin, most
largely contained in the true jalap (/2rogonium purga, or Jpomma
purge); the former is soluble in ether, the latter insoluble,
Fliickiger advocated the names ja/apurgin for the ether-insoluble
jalapin and orizabin for convolvulin, soluble in ether, but these
502 ORGANIC CHEMISTRY.
names have not been generally adopted. In the U, 5. the name
convolvulin is applied to the ether-insoluble hard resin which is
the medicinally active constituent of jalap.
Jalap-resin (Resina Jalape, U, 5. P.), is obtained by di
and percolating jalap tubercles (Jalapa, U. 8. P.), with aleohol,
distilling off part of the alcohol, pouring the remainder into water,
and washing and drying the precipitated resin. Jalap thoroughly
exhausted by this process should furnish, according to the Phar-
macopeia, not less than 8 percent. of resin, of which resin not more
than three-sixteenths should be soluble in ether, a test which
excludes resin of Tampico jalap and scammony resin, both of
which are soluble in ether. The tincture of jalap is sometimes
decolorized by animal charcoal, und the evaporated product sold
as ‘‘jalapin.”’
Jalap-resin is insoluble in oil of turpentine; common resin or
rosin, soluble. If the presence of the latter is suspected, the
specimen should be powdered, digested in turpentine, the mixture
filtered, and the filtrate evaporated; no residue, or not more than
that yielded by the turpentine itself, should be obtained,
Tampico Jalap, from Ipomea simulans, yields a resin which
apparently is chiefly convolvulin, but sometimes contains jalapin;
for asample obtained by Hanbury was entirely soluble in ether,
and another extracted by Umney was almost wholly soluble,
while Evans purified some, of which only half was soluble,
The Kaladana resin (Syn. Pharbitisin) obtained from the dried
seeds of Jpomera hederacea (Syn, Pharbitia Nil), is a resin analo-
gous to, if not identical with, resin of jalap.
Turpethum, Turpeth, is dried root and stem of Jpomma Turpe-
fhum, It contains turpethin, a resinoid glucoside resembling
jalapin in properties. The word turpefh is in Persian turbid, a
cathartic, or furbad, a cathartic root.
Logantn, ©,,H,,0,,, isa glucoside obtained from the pulp of
the fruit and from the seeds of Strychnos Nux-vomica, AM EE
(Nur Vomiea, U. 5. P.), by Dunstan and Short. Boiled with
dilute sulphuric acid, it yields glucose and /oganetin,
OvaBarn, O,H,,O,, (Arnaud); or C,,H,,0,,, isa very poi
glucoside resembling strophanthin, found in the wood of an
acokanthera and in arrow poisons prepared from this wood.
PICRORHIZIN is a bitter crystalline glucoside existing, to the
extent of 15 percent., in the dried rhizome of Picrorhiza Kurroa.
Boiled with 1 percent. aqueous hydrochloric acid, it yields glucose
und resinoid picrorhizetin. Picrorhiza is said also to contain
cathartic acid (Hooper). ae
PICROTOXIN is a crystalline bitter poisonous principle (racic,
picros, bitter, and rofixdy, foxicon, poison) occurring In
Indicus, the dried fruits of Anamirta paniculata. Ludwig regarded
it as a glucoside; but its constitution is not yet satisfactorily aseer-
tained, Barth and Kretschy state that the so-called pierotexin”
GLUCOSIDES. 503
may be separated into picrotoxin proper, C,,.H,.O,,H,O, which is
bitter and poisonous; picrotin, C,.H,,0O,,+nH O, which is bitter
but not poisonous; and anamirtin, C,H.O,,, which is neither bitter
nor poisonous. Schmidt asserts that the original picrotoxin is
definite, and has the formula C,,H,,O,,, but that some solvents
decompose it into picrofoxinin, C,.H,,O,, which is poisonous, and
pierotin, C,.H,O,, which is not poisonous.
POLYCHROITE, see p, 551, ,
Qvuassin, C,,H,,0,, Wiggers; or C,,H,,O0,, Christensen, obtained
from Quassia, U, 'S. P., is said to be a glucoside; but Oliveri and
Denaro question the statement, and find quassin to have the
formula C,,H,,0,,.
SALICIN,C,,H,,O,.—This substance (Salicinum, U. 8. P.), is
contained in and easily extracted from the bark of various species
of willow (Salix) and of Populus, It occurs in white, shining,
bitter crystals, soluble in 21 parts of water or 71 of alcohol at
ordinary temperatures,
Tests.—1. To a small portion of salicin placed on a white
plate or dish, add a drop of concentrated sulphuric acid; a
deep red color is produced.
2. Boil salicin with dilute sulphuric acid for some time ; it
is converted into saligenin or saligenol, CLH,O,, and glucose,
Test for the latter by the copper test,
O, + H,O = 0,8 (O08 )CH,O8 T CHO,
OH ‘Water aligeno a
3. To another portion of the liquid, carefully neutralized,
add a ferric salt; a purplish-blue color is sometimes produced,
due to the reaction of the saligenin and the ferric salt. The
snligenin is, however, so rapidly decomposed by acids into
saliretin, C,H,O, and water, that this reaction is almost value-
less as atest. The saligenin may, however, be obtained hy
the action of synaptase on salicin.
4. Heat a mixture of about 1 part of salicin, 1 of potassium
dichromate, 14 of sulphuric acid, and 20 of water in a test-
tube; a fragrant characteristic odor is evolved, due to the
formation of salicylaldehyde, C,H,OH.COH, an essential oil
identical with that existing in meadow-sweet (Spiraa Ulmaria)
and in heliotrope.
C,H.OH.CHOH + 0 — C,H.OH.COH + H,O
Baligenol Nascent Salicylaldehyde Water
504 ORGANIC CHEMISTRY.
SANTONIN, C,,H,,O,.—This substance is, apparently, the anhy-
dride or, rather, lactone,’ of a weak acid (Hesse) insoluble in
ammonia, but forming a soluble calcium salt. Indeed by boiling
santonin for twelve hours with baryta water, Cannizzaro has
obtained a salt from which hydrochloric acid separates santonic
acid, CHO, From a solution of calcium santonate the santonin
is precipitated by acids. Boiled for some time with dilute sul-
phuric acid, it yields 87 percent. of an insoluble resinous sub-
stance (santoniretin) and glucose (Kosmann), Santonin (Santeni-
num, U.S. P.), is official ; it is soluble in an aqueous solution of
twice its weight of sodium carbonate. Possibly (Berthelot) san-
tonin resembles carbolic acid,—in other words, is a phenol,
©,,H,,(OH),. Its glucosidal character i is questionable.
pcesa,—The process for its preparation consists in boiling
santonica, (Sanfonica, U. 8. P.), the dried, unexpanded flower-
heads or capitula of Artemisia panciflora) with milk of lime (whereby
calcium santonate is formed), straining, precipitating the san-
tonin or santonic acid by the addition of hydrochloric acid, wash-
ing with ammonia water to remove resin, dissolving in alcohol and
digesting with animal charcoal to get rid of coloring-matter,
setting the alcoholic solution aside to deposit crystals of santonin,
and purifying by recrystallization from alcohol (Mialhe).
Test.—To highly diluted solution of ferric chloride add an
equal volume of concentrated sulphuric acid, To this reagent
add the santonin or powder or substance suspected to be san-
tonin, and cautiously apply heat. A red, purple, and finally
violet color is produced (Lindo), Santonin added to warm
aleoholic solution of potassium hydroxide yields a violet-red
color.
SAPONIN, C, JH, .O,., H,O, is a peculiar glucoside occurring in
Soapwort, Saponaria, "the root of the common Pink, and many
other plants ; its solution in water, even though very dilute, froths
like a solution of soap. Heated with dilute acid it yields glucose
and sapogenin, C gts .O,. Pereira considered smilacin | salseparin
or parallin), one of the prine iple +s of the supposed activity of Sarsa-
parilla (: Sarsaparilla, U.S. P.), to be closely allied to, if not
identical with, saponin, According to Klunge (“* Pharmaco-
graphia’’), parallin, by act tion of ac ‘ids, yields parigenin, The
aqueous | solutions of parallin, fre oth w ‘hen shaken. Von Schultz
states that sarsaparil Ula contai ina three e homologous glucosides anal-
ogous to ‘saponin, namely, sarsaparill-saponin, CoH,,O%, sarsa-
saponin, O,,H,, pro ane Cpasalliny Cave
Ee ——
at t Jertain hyd roxyacids, by loss of ¥ vater, y ‘ield bi wtoues. Aromatic com-
pounds e onts vining Nie in Lhe | ortho ‘position and losing water by the oxi-
di: ation and re MOV al of | one or t1 w ro toms of tha ut hy ‘drogen furnish bodies
which pu iv be distinguishe ‘ls as tae ctama: yand lactims, >
GLUCOSIDES, 505
Saponin is also met within the root of Po/ygala Senega (Senega,
U. &. P.), though the activity of senega is said to be due to two
glucosides, senegin and polygalie acid,
Saponin is readily obtained from the bark of Quil/aja saponaria,
or soap-bark (Quillaja, U. 8. P.), by boiling the aqueous extract
in alcoho! and filtering while hot. Flocks of saponin separate on
cooling. It is a white, non-crystalline, friable powder.
The alleged toxic properties of commercial saponin are said by
Kobert to be due to sapotoxin and qui/laic acid which seem to be
identical with senegin and polygalic acid respectively,
ScamMontn, ©,,H,.O,, (apparently identical with the substance
called convolvulin in Britain).—Boil resin of secammony (fesina
Scammonii, U.S. P.), with dilute sulphuric acid for some time ;
glucose may then be detected in the liquid, a resinous acid termed
acammonolic acid, C\,H,,O,, being produced at the same time. This
acid is also obtained by the hydrolysis of convolvulin, Accord-
ing to Kromer, scammonin is oxidized by nitric acid into oxalic,
valeric, and butyric acids, carbonic anhydride, and an acid melt-
ing at 101° C., which is isomeric with sebacic acid, Potassium
permanganate oxidizes scammonin to oxalic and valeric acids, and
the monobasic scammonolic acid, Kromer gives the formula for
scammonin as CgH <Q...
Natural scammony (Scammonium, U.S, P.), is an exudation
from incisions in the living root of Convolvulua Seammonia, It con-
tains from 10 to 20 percent. of gum, and, therefore, when tritur-
ated with water, gives an emulsion. It should yield at least 75
percent. of resin soluble in ether. The official resin of secammony
contains no gum, and therefore gives no emulsion when triturated
with water,
Resin of Scammony is almost entirely soluble in ether, Spir-
gatis states that it is identical with the resin of Mexican Male
Jalap, which also is soluble in ether. Sulphuric acid slowly red-
dens it. It is said to be liable to adulteration with resin of true
jalap, guaiacum-resin, and common rosin. Resin of true jalap is
insoluble in ether, guaiacum-resin is distinguished by the color-
tests mentioned under GUATACIN, and rosin is recognized by the
action of sulphuric acid,
ScrLLAin.—Scehroff, and, afterwards Riche and Remont, be-
lieved the bitter principle of the squill-bulb (Sei//a, U. 8. P.), to be
a glucoside. Merck has extracted substances which he has termed
scillipicrin, scillitoxin, and ascillin, and to which the bitter taste
of squill is due. Scillitoxin appears to be identical with the acil-
lain of vy. Jarmerstedt. Schmiedeberg has given the name siniatrin
to a squill carbohydrate. Squill contains a large quantity of
mucilage.
The bulbous root of Crinum Asiaticum is included in the Pharma-
copeia of India, as a substitute for squill. It has not been chemi-
cally investigated,
506 ORGANIC CHEMISTRY.
STROPHANTHIN, (Strophanthinum, U. 5. P.), C Feist ;
OH, 0,,, Arnaud,—According to Fraser, this is the active prin-
ciple of strophanthus seeds (Strophanthus, U.S. P.), the ear
of Strophanthus Kombé, and is a glucoside. He obtained it
crystals, Acids convert it into glucose and crystalline panes Eis
thidin. Phosphomolybdie acid produces in solutions of strophan-
thin a bright bluish-green color. Feist states that it yields very
little, if any, glucose on hydrolysis, but gives, in addition to
strophanthidin, a white crystalline substance of the formula
C,,H,,O,,, melting at 207° C., and a sugar of unknown composi-
tion. Kohn and Kulisch have also investigated strophanthin,
but they are inclined to accept Arnaud’s formula, and to doubt
the correctness of Fraser's view and the glucosidal nature of
strophanthin. Helbing states that its aqueous solution yields,
with a trace of solution of ferric chloride and some concentrated
sulphuric acid, a reddish-brown precipitate which after an hour
or two turns green. Sulphuric acid colors strophanthin dark green,
changing to reddish brown, Possibly strophanthin is only one of
the active principles of the different species of strophanthus.
Strophanthus seeds are used in the preparation of Tinctura Stro-
phanthi, U.S. P. They contain nearly one-third their weight of
oil,
QUESTIONS AND EXERCISES,
Define glucosides, and mention those of pharmaceutical interest.—Con-
struct an equation illustrative of the formation of oil of bitter almonds
from amygdalin.—How much pure amygdalin will yield one grain of
hydrocyanic acid ?—To what does cherry-laurel water owe its activity?
—Meution the active principle of senna,—State the circumstances muda
which guaiacum-resin yields glucose.—Mention a test for guaiacum-resin.
—How may the adulteration of jalap- resin by rosin be detected ?—Enumer-
ate the tests for salicin.—How is santonin officially prepared Y—Name
sources of saponin.—What isthe difference between scammony and resin
of scammony ?—How would youdetect resins of turpentine, guaiacum, or
julap, in resin of scammony ?
UNCLASSIFIED MEDICINAL PRINCIPLES, ETC.
The following articles, employed medicinally in such forms as
Decoction, Extract, Infusion, Tincture, etc., contain active princi-
ples which have not yet been thoroughly examined, Some of
these principles have been isolated, and a few have been obtained
in the crystalline condition; but their constitution has not been
auflic iently well made out to admit of the classification of the
bodies either among a Ikaloids, elucosides, acids, or other well-
marked principles. —
UNCLASSIFIED MEDICINAL PRINCIPLES, ETC. 507
Agropyrum, or Triticum, U.S. P.,
th-grass.
A aphis (B. P, Add. 1900),
And is Cowles et Radix,
P.L, from Andrographis pani-
eulata, Kariyat, a bitter prin-
is, U.S. P.
A wm, U.S.P,, Canadian hemp.
(Hesperidin. )
Azadirachta Indica, Indian Aza-
dirach (B. P. Add, 1900); Asa-
dirachta Cortex et Folia, P. I.,
from Melia azadirachta, Neem
or Margosa. (A resin; CgH yO),
Broughton )
Bonducella Semina, P.1., from
Cresalpinta (Guilandina) Bou-
ducella. Bondue-aeecda or nickar-
nufa,
Buchu, U.S. P.
Butece Semina, B. P. Add. 1900,
Calendula, U. 8. P. Marigold
Calendulin Stoltze. )
Calotrepia, B, P. Add. 1900, and
P.1,, from Calotropis procera and
C.. gigantea. Mudar.
~ rast teh (Casearillin,
yalt,,O,)
Chulophullum Thalictroides, Blue
cohosh. Alkaloid?
Cimicfi ( Actora)
(Clangeifugin said by Conard
to be neutral, and by Falck
alkaloidal). Black cohosh or
black snake-root. Cimieifuga,
eurbiiie Semina Praeparata, melon
pumpkin seeds, B. P. Add. 1900,
or , ULB. P. from Cuewr-
bita maxima, Duch. (Cucurbita
Pepo, Linn.) A remedy for
lape-worm.
Cypripedium pubeacena Cypri-
pedin?). Ladies’ slipper ( Cypri-
pedium, U.& P.).
Euonymus atropurpureur, Fuony-
mus, U. S&S FP. Wahoo-bark.
(EKuonymin ?)
Eupatorium perfoliatum. Thorough-
ae or Boneset. Kupatorium,
A
racemorta
Gossypit Cortex. Cotton Root
- no U. 5. P. a
Julancha tinospora, P. Add.
saw rdiioke ( ae of “he
volia | Tinospore Radix
o Gadts P. I).
Hamamelis Virginica. Witch-
hazel.
The official portions are
Hamamelidis Cortez, U.S.P., the
source of Aqua Hamamelidix,
U.S. P., and Homomelidis Folia,
. U. 8S. P., the source of Fluid-
extractum Flamamelidia, U.S. P.
HHydrocotyles Folia, P. 1., from
Hydrocotyle Asiatica, Indian
nywort.
yqroplala (B. P. Add.1900), the
dried herb, H, hila spinosa.
Iria versicolor, ue flag. ( Tridin
or lrisin?) —
Kava (Kare Rhizoma, B, P. Add.
1900), a remedy in alcoholism.
Lactuca, (Lactucin, ete.). The
milk-juice, dried, yields Lactu-
cartum, U.S. P.
Lappa, U.8. P., Aretium Lappa,
oficinalia, Burdock
Lupulus,
Magnolia. Swamp sassafras, or
beaver tree,
Marrubium, U.S. P. Horehound,
Marrubein, a crystalline bitter
substance (Mein).
Matic Folia. Matico U. 8. P.
Phytolacen, U.S, P., Poke root.
Phytolaeccin, a crystalline sub-
stance (Claassen ).
Seutellaria, U. 8. P., Skulleap.
Soymida Cortez, FP. 1. ohun
rk, from Soymida febrijuga.
Teraracum, U.S. P., (Taraxacin).
Toddalia, the dried root-bark of
TYoddalia aculeata, B. P. Add.
10900; Toddalioe Radix, P. 1.
Triticum repens. Rhizome of
couch-grass, See A gropyrum,ante,
Veronica Virginica, roots and
rhizome. Culvers root; Lept-
andra, U.S. P. ( Leptandrin ?).
Vilurnum prun iotim, U. 6. P.,
Black haw. Viburnum opulua,
U.S.P. Cramp-bark. ( Viburnin).
ORGANIC CHEMISTRY.
ALEALOIDS.
Constitution of Alkaloids, or Organic Bases,
Natural Alkaloids, —The natural organic bases, alkaloids, or
alkali-like bodies (eidoc, cidos, likeness), have certain analogies
with ammonia, The constitution of some of them is compara-
tively simple, while in many cases it is exceedingly complex and
has not as yet been fully elucidated. All contain nitrogen, and
may be regarded as ammonia which has had its hydrogen replaced
wholly or in part by one or more organic groups of greater or less
complexity, Some of the more important alkaloids are closely
related to pyridine, quinoline, ‘ete., compounds which are referred
to further on. .
Numerous «rfijicial organic bases, having a very simple relation
to ammonia, have already been formed. These are commonly
called amines, and they are primary, secondary, or tertiary aceord-
ing as one, two, or three atoms of hydrogen in ammonia have
been replaced by radicals, as seen in the following general formula
(R=any univalent radical):—
R R
H}N R
i H
or in the following examples :—
C,H, C,H, } C,H,
HN C,H, $1 CH. \N
H | H | CH
Ethylamine Diethylamine Trieth ylomine
The primary and secondary amines are sometimes called amino-
bases and imino-bases respectively.
Formation of some of the Artificial Organic Bases.—A few illus-
trations will suffice, Just as the addition of hydrogen iodide, HI,
to ammonia, NH,, gives ammonium iodide, NH,I, so the addition
of ethyl iodide, C,H, or Etl (see p. 398), to ammonia gives ethyl-
ammonium iodide, NH.C,H.I or NH,EtI, A fixed alkali liberates
‘ammonia from ammonium iodide; it liberates ethyl-ammonia
or ethylamine, NH,Et, from ethyl-ammonium iodide. Ethyl-
amine with ethyl iodide, EtI, gives diethyl-ammonium iodide,
F
NHYC,H,),1 or NH,Et,1. From the latter potassium hydroxide
liberates diethylammonia or diethylamine, NHEt, Diethylamine
with ethyl iodide gives triethyl-ammonium iodide, NH(C,H,).1
or NHEtT. The latter with caustic alkali gives triethyl-ammonia
or triethylamine, NEt,, and this with ethyl iodide gives tetrethyl-
ammonium iodic le, N(C,H,),1 or NEt,I, which is not decompos-
able by potassium hydroxide, | ‘
What has just been stated respecting ethyl iodide is true of a
number of other o rganic iodides, so that a large number ofartificial
organic bases and their salts can be produced. The reactions are
' m/e proven
ALKALOIDS.
not always so sharp, however, as might be inferred from the pre-
ceding paragraph, mixtures of primary, secondary, and tertiary
compounds, rather than a single amine, being obtained. Some
of these artificial bases not only resemble natural alkaloids, but
yield solutions which are strongly caustic liquids, like ammonia
water.
The radicals in the amines which take the place of the hydrogen
in ammonia are not necessarily all of one kind as in the case of
the ethyl derivatives referred to above, but two or more different
radicals may be present in the same amine, Thus, for example,
we have methyl-ethyl-amylamine, C,H,,N, or NCH,C,H.C,H,,,
or NMeEtAy, a colorless, oily substance, of agreeable aromatic
odor, while such substances as metiyl-ethyl-propyl-isobutyl-am-
monium chloride, NCH,C,H,C,H.C,H,Cl, have also been prepared.
Analogues of Amines.—As might be expected from the analogy
of phosphorus, arsenic, and antimony with nitrogen, there are
also known phosphines, arsines, and stibines; bases resembling
amines, but containing the respective elements (P,As,Sb) in place
of the nitrogen of the amines.
Methylamine, CH,NH,, and trimethylamine, (CH,),.N, have been
obtained both artificially and from naturally occurring organic
materials. Methylamine was found by Schmidt, in Mercurialia
annua and M. perennis, and previously by Reichardt, who termed
it mereurialine. Trimethylamine is produced in large quantities in
the dry distillation of the evaporated residue of the spent wash
produced in beetroot spirit distilleries, |
Propylamine, CJA,NH,, is a volatile oil, one product of the
destructive distillation of bones and other animal matters.
Besides the amines derived from a single molecule of ammonia,
which are called monamines, there are also diamines, triamines,
ete., which may be looked upon as derivatives of two, three, ete.,
molecules of ammonia. Thus ethylene-diamine is represented by
the formula C,H,(NH,),. Diethylene-diamine, NH(C,H,),NH,
is used medicinally under the name piperazine ; its constitution
resembles that of piperidine (see p. 538), but with the group NH
taking the place of a CH, group in that compound,
Hydrorylamine,—Besides the various amines already mentioned,
ammonia may have one atom of its hydrogen displaced by
hydroxyl, hydroxylamine, NH,OH, resulting. Hydroxylamine
is formed by the reduction of the nitric acid, when zinc, dilute
sulphuric acid, and a little nitric acid interact. It yields substi-
tution products, as ethylhydroxylamine, NHC,H,OH, and addi-
tion compounds, as hydroxylamine hydrochloride, NH,OH, HCl:—
wt
H CH, CRY » -
H ws H N S H y N | H HCl
(H | on lon lon
Ammonia Hydroxylamine ‘Ethyl iydroxzylamine
. bydroxylamine hydrochloride
=
510 ORGANIC CHEMISTRY,
Hydroxylamine and aldehydes yield aldoximes, (eer aoe.
amine and ketones, such as acetone, yield acetoximes. |
uals, not limited to the requirements of medical and Seiten
tical students. )
Hydrazine, H,N—NH,. Diethylamine, by action of nitrous
acid, yields a nitroso-derivative which, on reduction, furnishes
what apparently is a diamidic compound—diethyl-hydrazine,
(C,H,),N—NH,. UHydrous hydrazine has the formula H,N—
NH,, H,0. Hydrazine itself cannot very easily be isolated. Its
salts with ordinary acids are generally crystalline, and isomorphous
with corresponding ammonium salts. Acidulated, they have very
powerful reducing properties, and act as strong poisons toward
the lower organisms. Phenylhydrazine, C,H,HN—NH,, is an
extremely useful agent ; employed in making antipyrine, various
coloring-matters, ete, It forms important compounds with the
sugars,
Azoimide or imidazoie acid, TIN,, is a substance closely resem-
bling the haloid acids, and was originally prepared by Curtius
from hydrazine and ethy] hippurate ; it may, however, be prepared
more easily by a method proposed by Wislicenus, in which soda-
mide, NaNH,, prepared by passing ammonia over melted sodium,
is heated with nitrous oxide.
Plant Alkaloids,—These are of great importance to the medical
and pharmaceutical student. They are treated in considerable
detail in the succeeding pages.
Animal Alkaloids,—Many well-known alkaloids occur in the
juice of the flesh, and in other parts of animals, wre: St
of meat contains abundance of crystals of creatine, C,H JNO
some creatinine, C,H.N,O. Creatine easily parts with the batters
of water and yields creatinine ; ; it takes up the elements of water
and yields sarkosine, C,H,NO,, and wrea, CH,N,O. Sarkosine is
methyl-glycocoll. Taurine, xe Al NSO, may be obtained from
bile; and it can be constructed artificially from its elements.
Some animal tissues, as of the spleen, brain, and pancreas, yield,
asa product of work, leucine, C H,,NO,, which oceurs in white,
pearly crystals ; also tyrosine, C WH, NO, Lecithin, which oecurs
in yolk of egg and in the brain, is a highly complex choline
derivative, being a distearic gly cerophosphorie choline ester,
, w, “OH
C,H, (C,,H,,0,),PO,¢ CO0,H,N(CH,),OH.
As Snaciec of some other animal alkaloids, Gautier has
obtained several new alkaloids from albuminoids, and hence has
termed them /encomaines Geirne upna, leucoma, white of egg), namely,
ranthocreatinine C, sH,, N O, crusocreatinine, CH oN O, amphicrea-
finine, C HN, oO . and pser udo-canthine, 0. TN, 0, “the leucomaines
and the animal alk: aloids generally are of great physiological
interest, Some of th ve leucomaines are toxic and indistinguishable
from ptomaines ; in fact, the three classes merge into one another,
ALKALOIDS.
Ptomaines.—A series of diamines, many of them toxic, have
been isolated, by Brieger, from decaying nitrogenous animal prin-
ciples, including the putrid albuminoids or proteids of the human
body itselfi—hence the name plomaines (rraua, ptoma, a corpse).
These have some medico-legal importance, but, inasmuch as they
may occur in the living body, poisoning the blood during the
progress of disease, especially disease associated with the develop-
ment of micro-organisms or microbes, that is, zymotic disease
(cin, zumé, leaven or ferment), they have great pathological
interest—indeed, physiological interest also, for one of a curari-
like character seems to play a part in the process of digestion.
The names of some of these bases are neurine, C,H,NO, and
neuridine, C,H,.N,, from putrid flesh ; muscarine, CH,.NO,, and
gadinine, © H,,.NO,, from putrid fish ; cadaverine, C, aN acl
perine, and putrescine, C,H,,N,, from putrid human remains,
choline being met with in the earlier stages of decay ; and ftetanine,
C,,H,,N,O,, (the administration of which to animals produced
symptoms resembling those of tetanus in man), from beef putrefied
by the agency of the microbe which is associated with the cause
of traumatic tetanus, so distressing to the human subject, T'yro-
foricon was the name given by Vaughan to a toxic ptomaine he
isolated from poisonous cheese (rvpdc, turoa, cheese ; rugiadv, toxicon,
poison), afterward from poisonous milk and cream, which, taken
as food, had caused more or less vomiting, headache, and diarrhcea.
Brieger states that when shell-fish is poisonous this is due to the
presence of a ptomaine he has named myftilorine, C,H,,NO,,
Para- and meta-phenylene-diamine appear to have all the char-
acters of leucomaines or ptomaines, the latter causing intense
influenza.
Alkaloid of both Plant and Animal Origin.—Choline, CH,,NO,,
occurs in the bile and the brain, also in ergot and ipecacuanha,
hops, areca nut, cotton-seed cake, Scopola Japonica, etc. Guanine,
C.H.N.O, and sarkine, C,H,N,O, are found in flesh and in young
plant leaves. Fresh meat furnishes carnine, C,H,N,O,, which
also occurs in yeast ; and befaine, C,H,,NO,, is found in beetroot,
cotton-seed cake, and in urine.
Attempts to form artificially the more important natural organic
bases commonly used in medicine have for the most part fniled,
although a few alkaloids, identical with the natural substances,
have been obtained synthetically (e. g., atropine and conine),
Many artificial colorific alkaloids of the amido-benzene (aniline or
phenylamine) type, and of a curious double nitrogen type (diazo-
benzene = C.H,.N:N.OH) have been obtained. But the type of
the natural medicinal alkaloids seems to be more closely related
to pyridine, C.H,N , and to quinoline or chinoline,C,H,N. Pyridine
is producible in various ways, but is contained in bone-oi/ (from
the distillation of bones—whence, also, pyrro/, C\H.N, and thence
iodopyrrol, or iodol, CA,HN (Jodolum, U. 8. P., a rival of iodo-
512 ORGANIC CHEMISTRY.
form), together with the homologues picoline, C,H,N (or methyl-
pyridine, ortho-, meta-, or para-); (utidine, OLH,N ; collidine,
O,H,,N ; etc. ; forming an homologous series of pyridine basex,
C -H,.,N ;
H
© N
o™ ow
OR Be. Be, HC CH
| |
HC HC CH
va 7
UC
r iI
Phenylamine or amido-benzene Pyridive
From quinine, ¢inchonine, and strychnine, by the disruptive
action of caustic alkalies, not only pyridine and homologues, but
also quinoline have been obtained. Quinoline can be made in
various other ways, especially (Skraup) from nitrobenzene, aniline,
and glycerin. Quinoline is closely related both to benzene and
to pyridine (see the following formula), Its relation to naphtha-
lene (two carbon-conjoined benzene residues) is similar to that of
pyridine to benzene.
H H H
C N
a ~. A We
a 0 CH
He
Naphthalene Alpha and beta positions Quinoline
Both pyridine and quinoline form additive compounds with
hydrogen (see Piperidine, p. 538),
By adding six atoms of hydrogen to pyridine, piperidine is
obtained: and conine, the alkaloid of hemlock, is piperidine with
propyl (C. H1,) replacing one of the hydrogen atoms. It has been
formed : irtific ially by Ladenburg from picoline (see also eegonine,
trop ine, e te ).
Chemists, in the » hope, doubtless, of discovering how to produce
the valu: uble -medici inal ; alk: ale nids -artific ially, have prepared a
number of alkaloidal de rivatives of quinoline, One of them,
kairine, somewhat re sem bles s quinine.
It seems reason: aly le to sup pe se > that the study of the constitution
of the alkaloids, in lig ht of the p roduc ts s resulting from the vari-
ous decompositions w hic h they under rgo, will in time lead chemists
to the successful sy nthe aia of, , at le ast, some of the most important
ALKALOIDS. 513
alkaloids. Indeed, the rapid progress of investigation and the
consequent extension of our knowledge of this department of
chemistry, justify the inference that we are at last almost ‘‘ within
measurable distance’’ of the artificial production of most of the
nutural alkaloids. This is a subject of financial and general com-
mercial weight; of considerable technological, including phar-
maceutical, importance; of very great medical consequence,
especially taken in connection with its ramifications; and of tran-
scendent scientific interest as illustrating the working of nature's
forces within the molecules of matter.
Note on Nomenclature of Natural Alkaloids.—The first syllables
of the names of the natural alkaloids frequently recall the name
of the plant from which they are obtained, or some characteristic
property, while the final syllable is either ine or ia. The com-
pilers of the United States, British, French, and German Phar-
macope@ias have uniformly adopted the termination ine. The
names of the salts of the alkaloids are given on the assumption
that the acid simply unites with the alkaloid without the elimina-
tion of water. Thus morphine hydrochloride (sometimes termed
‘*hydrochlorate ’’) is regarded as morphine which has united with
hydrochloric acid. Acids in general unite with alkaloids and
form additive salts of a similar kind.
Antidotes.—In cases of poisoning by alkaloids, emetics and the
stomach-pump must be relied on rather than chemical agents.
But astringent liquids may be administered, for tannic acid pre-
cipitates many of the alkaloids from their aqueous solution,
absorption of the poison possibly being thus retarded.
MORPHINE AND OTHER OPIUM ALKALOIDS,
Morphine.
Oceurrence.—Morphine or morphia, C,,H,,NO,, H,O, occurs in
opium (the inspissated juice of the seed-capsule of the White
Poppy, Papaver somniferum) perhaps partly as morphine meconate
[(C,,H,,NO,),, C,H,O,, 5H,0; Dott] and sulphate, The dried
poppy-capsule contains opium principles, but they vary much in
nature and proportion: the presence of morphine, narcotine, and
meconic acid has been demonstrated; also (by Groves) of codeine
and narceine, Ordinary Asia-Minor opium (Turkey, Smyrna, or
Constantinople opium) contains, when dried, from 10 to 165 per-
cent, of morphine. The Pharmacopeeia directs that opium used
for officially recognized purposes, other than the manufacture
of alkaloids, or of extract of opium of official strength, must con-
tain not less than 9 percent. of morphine, when the opium 1
quantitatively analyzed (#ee p. 794) by the official method,
Morphine Hydrochloride.—The hydrochloride, C,,H,NO,,
HC1,3H,0 (Morphine: Hydrochloridum, U.S.P.), occurs in slender
white acicular crystals; it is prepared by simply decomposing an
514 ORGANIC CHEMISTRY,
aqueous infusion of opium with calcium chloride, calcium meeo-
nate and morphine hydrochloride being produced. (If the imfu-
sion, which is always acid, be first nearly neutralized by the
cautious addition of small quantities of a very dilute ammonia
water, the calcium chloride then at once causes precipitation of
calcium meconate, which can be filtered off, leaving a
solution of morphine hydrochloride. On the large scale the
details are somewhat different.) The filtered liquid is evaporated,
and the impure morphine hydrochloride which crystallizes out on
cooling is redissolved in water and treated with animal charcoal;
the morphine is then precipitated from the still colored liquid hy
addition of excess of ammonia, separated by filtration, and dis-
solved in hot dilute hydrochloric acid; morphine hydrochloride
separates out on cooling.
Morphine hydrochloride deposited from a hot solution in about
twenty times its weight of alcohol is anhydrous, :
Morphine Acetate and Tartrate.—Morphine acetate, C,,H,NO,,
C,H,0,, 83H,0 (Morphine Acetas, U. 8. P.), is prepared by dis-
solving morphine (Morphine, U, 8. P.), in acetic acid. Morphine
tartrate, (C,,H,,NO,),, C,H,O,, 83H,0 may be prepared by neutral-
izing a mixture of morphine and water with tartaric acid.
Morphine hydrochloride, acetate, and tartrate are soluble in
water, but the solutions are not stable unless acidulated and con-
taining alcohol. Even solid morphine acetate is unstable, slowly
decomposing into acetic acid and morphine; hence the acid odor
of morphine acetate; hence, too, the necessity, when a solution
of morphine acetate of perfectly definite concentration is required,
of preparing it from a weighed quantity of hydrochloride, or
of pure crystalline morphine. :
Morphine Sulphate, (C,,H,,N O,)s, H,S0,, 5H,O (Morphine Sul-
phas, U.S. P.), is prepared by neutralizing precipitated morphine
with dilute sulphuric acid. It occurs in white silky erystals,
soluble in water.
Analytical Reactions.
1. To a minute fragment of a morphine salt add one drop
of water and warm the mixture until the salt dissolves, then
stir the liquid with a glass rod moistened with concentrated
neutral solution of ferric chloride; a dirty-blue color is pro-
duced.
Even in dilute solutions morphine reduces potassium ferri-
cyanide to ferrocyanide, hence may be detected by the bine
precipitate (Prussian blue) produced on the addition of ferne
chloride and ferricyanide. Other substances, but no other
official alkaloids, give this reaction,
ALKALOIDS. 515
2. To a drop or two of a concentrated solution of a mor-
phine salt in a test-tube add a minute fragment of iodic acid,
(HIO,, p. 280); iodine is set free: Into the upper part of the
tube introduce a glass rod moistened with mucilage of starch,
and warm the solution; dark-blue “iodide of starch” is pro-
duced. If the mixture of morphine and iodic acid be shaken
up with chloroform or carbon bisulphide, a violet solution is
obtained. This reaction is only confirmatory of others, as
albuminous matters also reduce iodic acid.
5. To a few drops of an aqueous infusion of opium add a
drop of neutral solution of ferric chloride ; a red solution of
ferric mecovate is produced. Add solution of corrosive sub-
limate ; the color is not destroyed (as it is in the case of ferric
thiocyanate, a salt of similar tint). In cases of poisoning by
a preparation of opium, this test is almost as conclusive as a
direct reaction of morphine (the poison itself), meconic acid
being obtainable from opium only.
4. According to Lamal, morphine solutions give, on addi-
tion of uranium acetate, a reddish-brown color, which disap-
pears on adding acids, while, on adding caustic alkalies a deep
red precipitate is formed, which turns yellow on adding an
excess of the reagent. The test is best made by putting 2 to
10 drops of the morphine solution into a porcelain dish and
adding the same quantity of uranium solution (0.015 gramme
of uranium acetate and 0.01 gramme of sodium acetate in 5
Ce, of water). After evaporating on the water-bath, concen-
tric, bright red or hyacinth-red spots are left. The reaction
is still visible with 0.05 milligramme of the alkaloid. Most
of the other-alkaloids give no reaction; salicylic acid gives
brick-red spots; tannin, gallic acid, and pyrogallol brown
spots. Phenol gives a brown color, slowly disappearing on
warming. The coloration with uranium acetate is very per-
manent,
Other Reactions —Add sodium carbonate to a solution of
a morphine salt ; a white precipitate of morphine is produced
slowly, and is of a crystalline character if the solution is di-
lute. Collect this precipitate and moisten it with neutral solu-
tion of ferric chloride; the bluish tint above referred to is
produced.—Add an alkali to a solution of morphine hydro-
chloride, acetate, or tartrate ; morphine is precipitated, soluble
in excess of fixed alkali, far less readily so in ammonia,—
Moisten a particle of a morphine salt with nitric acid; an
orange-red coloration is produced. Warm some morphine
O16 ORGANIC CHEMISTRY.
with concentrated sulphuric acid and sodium arsenate ; a blue-
green tinge results—To morphine add concentrated sulphuric
acid, mix, and add powdered bismuth nitrate to the fluid ; the
mixture turns dark brown or black.—Heat morphine on plat-
inum foil ; it burns away entirely.
Codeine.
Codeine, or Codeia, C,,H,,NO,, H,O, methyl-morphine, is an-
other officially recognized opium alkaloid (Codeina U,S. P.), It
dissolves in the slight excess of ammonia employed for precipita-
ting morphine in the foregoing process for the preparation of
morphine hydrochloride, It is obtained by evaporating the am-
moniacal filtrate, treating the residue with water, al
with potassium hydroxide, and purifying the precipitated alkaloi
by recrystallization from ether. Codeine may also be obtained by
heating a sodium compound of morphine, C,,H,NaNO,, with
methyl iodide, CH,I; sodium iodide and methyl-morphine or
codeine result. It occurs in white trimetrie crystals, soluble in
88 parts of water or ammonia water, readily soluble in aleohol,
in chloroform, and in diluted acids, It is soluble in 12.5
parts of ether. The aqueous solution has a bitter taste and an
alkaline reaction. The alkaloid dissolves in an excess of sul-
phuric acid, forming a colorless solution, a small quantity of
which, when gently warmed on a water-bath with 2 drops of
solution of ammonium molybdate, or with a trace of ferric chlo-
ride or potassium ferricyanide, develops a blue or bluish-blaeck
color, which, on the addition of a minute trace of dilute nitric
acid, changes to a bright scarlet, becoming orange. Heated to
redness in air, it yields no ash. It reduces a solution of one part
of ammonium selenite in twenty of concentrated sulphuric acid,
yielding a green color (Lafon). Codeine neither gives a blue
color with ferric chloride nora red with nitric acid. Both codeine
and morphine when heated with a mixture of concentrated sul-
phuric acid and sodium arsenate give a blue color, the morphine *
yielding a greenish blue and the codeine a violet blue. —
Codeine Sulphate, (C,,H,,NO,),H,SO,, 5H,0O, (Codeine Sul-
phas, U. 8. P.), and Codeine Phosphate C,H, NOJH,PO,, 26,0
( Codeine Phosphas, U. 8. P.), are official.
Dionin, is ethylmorphine hydrochloride; C,,H,,NO,,
HCI,H,O, — |
Heroin is diacetylmorphine, ©,,H,,NO(C,H,0,),. Both the base
itself and its hydrochloride are used in medicine,
Aromorpuing, C,,H,.NO,
The alkaloid apomorphine (472, apo, from, and ine) was
obtained from morphine by Matthiessen and Wright. It produces
ALKALOIDS, 517
remarkable physiological effects; one-tenth of a grain (in aqueous
solution) injected under the skin, or a quarter of agrain taken
into the stomach, produces vomiting in from four to ten minutes,
Preparation.—Morphine hydrochloride or codeine hydrochloride
is hermetically sealed in a thick tube with considerable excess of
hydrochloric acid, and heated to nearly 300° F. (148.8° C.) for
two or three hours. The product is purified by diluting the con-
tents of the tube with water, precipitating with sodium bicarbo-
nate, and treating the precipitate with ether or chloroform, On
shaking up the ethereal or chloroform solution with a very small
quantity of concentrated hydrochloric acid, the sides of the vessel
become covered with crystals of the hydrochloride of the new
base (Apomorphine Hydrochloridum, U. 8. P.), These may be
drained from the mother-liquor, washed with a little cold water,
in which the salt is sparingly soluble, recrystallized from hot water,
and dried on bibulous paper or over sulphuricacid. The formula,
G,,H,,NO,,HCl, may be derived from that of morphine by ab-
straction of the elements of water. With solution of apomor-
phine hydrochloride, sodium bicarbonate produces a precipitate
which becomes green on standing and then forms a solution which
is purple with ether, violet with chloroform, and bluish-green
with aleohol. With dilute test-solution of ferric chloride it gives
a deep red, and with nitric acid a blood-red coloration.
Other alkaloids exist in opium, In the preparation of
morphine a considerable quantity of narcotine, C,,H,,NO,, or
C,H,,(OCH,),NO, an alkaloid of very weak basic properties,
remains inthe exhausted opium, and may be extracted by
digesting in acetic acid, filtering, and precipitating by adding am-
monia. It crystallizes in brilliant needles from aleohol or ether,
The formula of its hydrochloride is C,,H,,NO,,HCI,H,0, By ox-
idation it yields cofarnine and an acid termed opianie, From the
mother-liquors there have also been obtained thebaine, C,,H,,NO,,
papaverine, (C,,H,,NO,, Hesse; C,H,,NO, Merck), narceine,
C,,H,,NO,, eryptopine, O,H,,NO,, meconin, CHO, mecon-
oisin, CH,O,, laudanine, C,H,.NO,, codamine, C,H,.NO,,
gaoscopine, OHNO, preudomorphine, C,H,N,O,, protopine,
CH, NO;, laudanosine, C,,H,NO,, hydrocotarnine, C,,H,NO,,
rheadine, ©,H,NO,, meconidine, ©,H,,NO,, lanthopine,
C..HLNO,. ~~
A little acetic acid also exists in opium (D, Brown).
Constitution of Morphine.—Theopium alkaloids, like the cinchona
alkaloids, have been attacked by many chemists in the hope that
analytical or, in a sense, destructive investigation would lead to
synthetical or constructive operations : and many interesting and
promising results have been obtained. It is found that morphine
is a tertiary base; it vields pyridine in several reactions, support-
ing the view that it is a pyridine derivative. By suitable oxi-
dation, it yields picric acid, and by fusion with caustic alkali,
518 ORGANIC CHEMISTRY.
protocatechuie acid, both which reactions indicate relationship
to benzene, The nitrogen atom in morphine appears to have a
methyl group attached to it, But the subject is not yet suffi-
ciently developed for useful study by ordinary students of medi-
cine or pharmacy.
QUESTIONS AND EXERCISES.
Write some general formuls of artificial alkaloids.—Name the substan-
ces represented by the following formul# ;—
(sH; ) CoH; ) aT CHy CH; CHs
H ;N, ‘sH;;N, CsHs?N, H ;N, CHs;N, CHs?>N
H H CsHis } H H CH,
Describe the treatment in cases of poisoning by alkaloids.—Give a process
for the preparation of morphine hydroc hloride, In what form does mor-
hine occur in opium t—How is morphine acetate prepared }—What plan
is adopted for preventing the decomposition of the official morphine selu-
tions *—Mention the analytical reactions of morphine,—In addition to the
reactions of morphine, what test may be employed in searching for opium
in # liquid or semi-fluid material ?/—Describe the relation of morphine
to codeine.—How is apomorphine prepared and what are its properties?
QUININE AND OTHER CINCHONA ALKALOIDS.
Quinine; CoHN,O, 3H,0
Source. —Quinine (Quinina, U. 8. P.), and other alkaloids exist
in the bark of various species of Cinchona (Cinchona, U.S. P.
and Cinchona Rubra, U. 8. P.), and Remijia Ainafes, or rather,
qu inatea,*
Extraction of the Mixed Alkaloids. 7
powdered cinchona with a quarter of its weight of slaked lime
and a little water, and extract with a mixture of one part by
volume of amyl aleohol with three of benzol. Shake the
liquid product i ina separating funnel with an ounce of water
ac idulated with sulphuric or hydrochloric acid. Draw off the
aqueous liquid, which contains the alkaloids as acid salts, and
add to it a slight texc ess of ammonia. Collect the precipitated
alkaloids. on a filter. wash, and dry by exposure to air, or in
a desiccator over sul Mpa ac “id, For the separation and
'Quinie Acid, CyH1s Oo, occurs in cine shona, coffee, holly, ivy, onk,
elm,
etc. He ated it y ie sid s hydroquinone, C ‘6Hy(OH) ig. Oxidized it gives quin-
one, OHO Dy whie h is probably a di- ke stone, C “Hal O)2
or Cy Hy— Get >CaHs. The homologues of ber nzene yield other “quinones.”
ALKALOIDS. 519
assay of the cinchona alkaloids, operations which should not
be attempted at this stage of study, the advanced student
should consult the directions given in the U. 8. P.
Quinine Sulphate (Quinine: Sulphas, U.S. P.), may be prepared
by treating cinchona with dilute hydrochloric acid, precipitating
the resulting solution of quinine hydrochloride by means of sodium
hydroxide, and redissolving the precipitated quinine in the proper
quantity of hot dilute sulphuric acid. Quinine sulphate crystal-
lizes out on cooling in silky acicular crystals, having the formula
(C,H,,N,O,), HS0,,7H,O. In dry air it loses, by efflorescence,
five-sevenths of its water.
Quinine sulphate, the ordinary or so-called neutral sulphate, is
only slightly soluble in water; on the addition of dilute sulphuric
acid Quinine Bisulphate, C,H, N,O,, oe »TH,O ( Quinine Bisul-
phas, U.S. P.), is formed, which is reely soluble. The latter
salt may be obtained in large rectangular prisms. A soluble acid
sulphate having the formula C,H,,N,O,, 2H,S8O,, 7H,O, also
exists. Quinine sulphate is much more soluble in alcohol or alco-
holic liquids than in water.
Quinine Hydrochloride (Quinine Hydrochloridum, U. 8. P.),
may be prepared by neutralizing quinine with hydrochloric acid.
Its formula is C,.H,.N,O,,HCI,2H,O. It is soluble in about 18
parts of water at 25° C., the sulphate requiring 720. The two
salts resemble each other in appearance, but the crystals of the
hydrochloride are commonly somewhat Jarger than those of the
sulphate. |
The remaining official preparations of quinine are the hydro-
bromide, C,,H,,N,O,H Br, HO. (Quinine Hydrobromidum, U.8.P.),
the oleate (Oleatum Quininer), the salicylate, (C,,H,,N,O,,C,H,O,),
HO, (Quinine Salieylas, U, 8. P.), and the scale compounds
already mentioned (pp. 158, 160).
Reactions.
1. To an acidulated solution of a quinine salt add fresh
bromine-water, shake, and then add ammonia water ; a green
coloration (thalleioquin) is produced. Chlorine-water, or solu-
tion of chlorinated lime may be used instead of bromine-
water.
2, Repeat the foregoing reaction, but prior to the addition
of ammonia water add solution of potassium ferrocyanide ;
an eyanescent red coloration is produced (Livonius and
Vogel ).
8. To an aqueous solution of a soluble quinine salt add solu-
tion of ammonium oxalate; a white crystalline precipitate of
quinine oxalate, soluble in acids, is produced. If the solution
520 ORGANIC CHEMISTRY,
to be tested be made from ordinary quinine sulphate, excess
of the latter should be added to water very faintly acidulated
with sulphuric acid, and the undissolved crystals removed by
filtration.
4. A saturated aqueous solution of any neutral quinine salt
is made by dissolving so much of the salt in hot water that
some shall separate when the mixture has cooled to about
60° F, (15.5° C.). After standing for some time, filter. To
the filtrate, ether which has been washed with water is added
until a distinct layer of ether remains undissolyed, and then
ammonia in slight excess, After agitation and rest for fifteen
minutes, all precipitated quinine will have redissolved.
Note.—In the case of quinidine salts well-defined crystals appear
at the junction of the aqueous and ethereal layers, especially after
standing. In the case of cinchonidine salts a thick layer of small
crystals appears at once. In the case of cinchonine salts the undis-
solved alkaloid makes the ethereal layer nearly solid. In testing
quinine for other alkaloids evaporate the aqueous solution to one-
fifth.
5. Formation of Quinine Iodo-sulphate. Dissolve quinine
sulphate in dilute alcohol slightly acidulated with mah uric
neid, and add an alcoholic solution of iodine; a black precipi
tate forms. Allow the precipitate to settle, pour away
liquid, wash once or twice with cold aleohol and then boil with
alcohol ; on cooling minute crystals separate. This iodo-sul-
phate is sometimes termed Herapathite, from the name of one
of the chemists who discovered it in 1852. The use of
plates of this substance instead of tourmaline in certain forms
of polarizing apparatus has been suggested, as they behave as
tourmaline does toward light passing through them. Under
the name of “iodide of hydriodate of quinine,” Bouchardat
described and used it in 1845, It is so slightly soluble in
alcohol that by its means quinine can be fairly well sey
from its admixture with the other cinchona alkaloids. Accord-
ing to Jorgensen it has the formula 4C,H,,N,O, 3H 80,,
2H, I2H,0,
6, Prepare a saturated solution of ordinary quinine sulphate
in water at about 60° F. (15.5° C.), and add to 5 volumes of
that solution 7 volumes of ammonia water (sp. gr. 0.96).
The alkaloid which is at first precipitated redissolves upot
slight agitation if the quinine sulphate is free from anything
hut traces of other cinchona alkaloids, If, however, more than
ALKALOIDS. 521
traces of quinidine, cinchonidine, and cinchonine salts be pres-
ent, a permanent precipitate remains, This is Kerner’s
method of testing quinine sulphate for other cinchona alka-
loids, It turns upon the fact that the solubility of the cin-
chona alkaloid sulphates in water is in the opposite order to
the solubility of the alkaloids themselves in solution of am-
mona.
Other Characters—Concentrated sulphuric acid dissolves
quinine with production of only a faint yellow color, which is
not increased by warmth.—Quinine and its salts, heated on
platinum foil, burn away entirely.— Most quinine salts when
in solution have a beautiful blue fluorescence. They rotate
the plane of polarization of light to the left.—Quinine is solu-
ble in alcohol, ether, benzol, and chloroform, Quinine sul-
phate is rather sparingly soluble in chloroform, and only
slightly soluble in water. Its solubility in chloroform is
increased hy the presence in solution of quinidine and cin-
chonine sulphates (Prescott), and its solubility in water is
decreased hy the presence in solution of ammonium sulphate
(Carles). The slight solubility of quinine sulphate and iodo-
sulphate in water distinguishes quinine from the other cin-
chona alkaloids, including the “amorphous alkaloids,” or
quinoidine,
Quinidine, C,,H,,N,O, (the conquinine or conchinine of Hesse),
is an isomer of quinine, Its salts are fluorescent, and yield thal-
leioquin with chlorine- or bromine-water and ammonia. They
rotate the plane of polarization of light to the right. Quinidine
is insoluble in water and sparingly soluble in ether (see Quinine,
4th Analytical Reaction). It is soluble in alcohol, benzol, and
chloroform, ITtis less soluble than quinine in ammonia, 6 volumes
of a saturated aqueous solution of quinidine sulphate requiring 60
to 80 yolumes of ammonia solution (sp. gr. 0.96), Its sulphate is
more soluble in water and chloroform than quinine sulphate,
(uinidine tartrate ia soluble in water. The hydriodide is inaolu-
ble in water and dilute alcohol, and occurs as gritty crystals, The
other cinchona alkaloid hydriodides, though more soluble than
quinidine hydriedide, sre sometimes precipitated from neutral
concentrated solutions as amorphous or semi-liquid precipitates,
These, however, are soluble in dilute alcohol. |
_Cinchonidine, C,JH,,N.O.—The sulphate, (C,,H,,N,O),, HO,
38H,0O, may be obtained from the mother-liquors from the erystal-
lization of quinine sulphate. When perfectly pure, cinchonidine
salts do not yield thalleioquin, and are not fluorescent. Even
good commercial salts, however, nearly always give both reactions,
522 ORGANIC CHEMISTRY.
Cinchonidine salts rotate the plane of polarization of light to the
left. Cinchonidine is insoluble in water und nearly so in ether,
(See Quinine, 4th Analytical Reaction.) It is soluble in alcohol,
benzol, and chloroform. It is less soluble in ammonia water
than quinine, 5 volumes of a saturated aqueous solution of cin-
chonidine sulphate requiring about 80 volumes of ammonia water
(sp. gr. 0.96). It is true that cinchonidine is dissolved as
readily as quinine if excess of ammonia water is quickly mixed
with the solution of the cinchonidine salt; but from such a
solution cinchonidine soon crystallizes out, while quinine
remains dissolved for many hours. Cinchonidine sulphate
(Cinchonidine Sulphas, U. 8. P.), and hydriodide are soluble in
water, but the sulphate, like quinine sulphate, is sparingly soluble
in chloroform. Cinchonidine tartrate is insoluble in water; and
in this form cinchonidine is usually separated from neutral solu-
tions containing the other cinchona alkaloids except quinine, the
filtrate from the precipitate of tartrate yielding cinchonine on the
addition of ammonia,
Cinchonine, C,H,,N,O, is an isomer of cinchonidine. The
sulphate may be obtained from the mother-liquors from the erys-
tallization of the quinine, cinchonidine, and quinidine sul
by adding sodium hydroxide to precipitate the alkaloid, washing
with alcohol until free from other alkaloids, dissolving in sulphuric
acid, and, after purifying the solution with animal charcoal,
allowing to crystallize. When quite pure, its salts are not fluores-
cent and do not yield thalleioquin, but as in the case of cinchoni-
dine, most commercial specimens of cinchonine salts nearly always
give both reactions. Cinchonine salts rotate the plane of polariza-
tion of light to the right, Cinchonine is insoluble in water and
nearly soin ether. (See Quinine, 4th Analytical Reaction.) It
is soluble in chloroform, benzol, and alcohol. Chloroform con-
taining one-fourth of its weight of alcohol dissolves cinchonine
much more readily than either alcohol or chloroform alone.
Cinchonine is insoluble in ammonia solution, Cinchonine
sulphate (Cinchonine: Sulphas, U. 8, P.), tartrate, and hyd ide
are soluble in water, and the sulphate, like quinidine sulphate, is
soluble in chloroform, In mixtures of cinchona alkaloids this
alkaloid is precipitated by alkali after the others have been sucees-
sively removed by ether, sodium tartrate, and potassium iodide.
‘“* Quinoidine,"" ‘* chinoidine,”’ or the ‘‘ amorphous alkaloid.” —
Cinchona. barks generally contain some alkaloid isomeric with
quinine which, like quinine, is soluble in ether, but the ordinary
sulphate and iodo-sulphate are not crystalline and are soluble.
These salts are semi-solid resinous-looking substances. The iodo-
sulphate is used in De Vrij’s method for the separation of mixed
alkaloids, Quinoidine is usually obtained along with the quinine,
ete., extracted from the mixed alkaloids by ether, and remains in
the mother-liquor, from which it is precipitated by an alkali,
ALKALOIDS. 523
Quinicine and cinchonicine, are alkaloids produced by the action
of heat on quinine or quinidine and on cinchonidine respectively.
They also are isomers, Hesse says polymers, of the parent alka-
loids. Both yield crystalline salts. Qvuiniretin is the name given
to the brown or reddish-brown indifferent substance into which
quinine in aqueous solution is converted when much exposed to
light.
Quinamine, C,,H,,N,O,, is a fifth cinchona alkaloid obtained by
Hesse in 1872 from the bark of Cinchona succirubra. Its solution
is not fluorescent, and does not yield thalleioquin. Another
alkaloid, cinchamidine, C,,H,,N,O, detected by the same chemist,
is identical with hydrocinchonidine.
Cupreine, C,,H,,.N,O,, ia an alkaloid discovered simultaneously
by Howard and Hodgkin, by Paul and Cownley, and by Whiffen,
in the bark of a Remijia (allied to Cinchona) and termed euprea
bark, It closely resembles quinine, but is sparingly soluble in
ether. It may be converted into quinine by heating its sodium
compound with methyl chloride; whence it appears that quinine
is methy]-cupreine. The substance at first termed homoquinine or
ultraquinine is a compound of cupreine and quinine, C,,H,.N,O,,
C,,H,,N,O,, 4H,0.
Hydroquinine, C,H,.N,0,, containing two more atoms of hydro-
gen than are present in the quinine molecule, is an alkaloid asso-
ciated with quinine in minute quantity in cinchona bark, It
remains in the mother-liquor when quinine sulphate is crystallized
from an acid solution. Its characters are closely allied to those
of quinine and its therapeutic action is similar, It was discovered
by Hesse.
Constitution of the Cinchona Alkaloids,—This is not yet clear,
though great advances have been made. In the course of the
investigations derivatives of quinoline have heen obtained, which
more Or less resemble quinine; these are sairine, kairoline, and
thadline.
Strychnine.
Source.—Strychnine or strychnia, C,,H,,N,O,, exists, to the
extent of about 1 percent., in Nux Vomica (Atrychnos Nuxvomica),
also (Shenstone) in minute quantity in the bark of the Nux
Vomica tree (false angostura bark) and to 1.0 or 1.5 percent. in
St Ignatius’s bean (Strychnoe Ignatius), partly, at least, in com-
bination with strychnic or igasuric acid. Crow also found it in
the bark of S. Jgnatiua,
Preparation.—Nux Vomica seeds, disintegrated by steaming,
and, after drying, grinding in a coffee-mill, are exhausted with
aleohol, the latter is removed by distillation, the extract dis-
solved in water, coloring-matters and organic acids precipitated
by adding lead acetate, the filtered liquid evaporated to a
524 ORGANIC CHEMISTRY.
small bulk, the strychnine precipitated by means of ammonia,
the precipitate washed, dried, and exhausted with the recovered
aleohol, the latter again removed by distillation, and the residual
liquid set aside to crystallize. Crystals of strychnine having
formed, the mother-liquor (which contains the brucine of the seeds)
is poured away, and the crystals of strychnine are washed with
alcohol (to remove any brucine) and recrystallized. This alkaloid
is official (Strychnina, U.S. P.).
Properties.—Strychnine occurs in colorless, transparent, pris-
matic crystals, or a white crystalline powder, odorless and having
an intensely bitter taste, perceptible even in solutions of 1 in
700,000. Permanent in the air. It forms salts with acids,
The sulphate (Strychnine Sulphas, U. 8. P.), has the formula,
(C,,H,,N,O,),HS80,, 5H,0. It is soluble in 31 parts of water,
The citrate (C,,H,.N,O,),,C,H,O,, 4H,0 (or 6H,O) dissolves, at
60° F., in about 40 parts of water and 115 parts of alcohol. TI
hydrochloride has the formula C,, H,,N,O.,HC1,2H,0, and issolu-
ble in 35 parts of water. Strychnine nitrate (Strychnine Nifraa,
U.S, P.), C,,H.,N,O,, HNO,, is official, A number of erystal-
line, well-defined acids have been obtained from strychnine by
oxidation,
Analytical Reactions of Strychnine.
1. Place a very small fragment of strychnine on a white
plate, and near to it also a small piece of potassium dichro-
mate; to each add one drop of concentrated sulphurie acid ;
after waiting a minute or so for the dichromate to fairly tinge
the acid, mix the two drops of liquid by means of a glass
rod ; a beautiful purple color is produced, quickly fading into
a yellowish-red. The following oxidizing agents may be used
in place of the dichromate:—lead peroxide, black manganese
oxide, potassium ferricyanide, potassium permanganate, or
ammonium vanadate,
This reaction is highly characteristic and delicate; a minute
fragment of strychnine dissolved in much dilute aleohol, or,
better, chloroform, and one drop of the solution evaporated to
dryness on a porcelain crucible-lid or plate, yields a residue
which immediately gives the purple color on being oxidized in
the manner directed.
2. Strychnine evaporated with nitric acid, and the residue
moistened with alcoholic potassium hydroxide, and again eva
* s e ® « . rt ,
orated, gives a yellow coloration, passing into reddish-yiolet
ALKALOIDS. 526
on addition of more potassium hydroxide, and becoming yellow
again on the addition of water. When atropine is treated
in the same way a violet residue is obtained which becomes
colorless on adding water.
Other Reactions.—Concentrated sulphuric acid does not act on
strychnine, even at the temperature of boiling water, a fact of
which advantage is taken in separating strychnine from other
organic matter for the purposes of toxicological analysis.—
Potassium thiocyanate produces, even in dilute solutions of
strychnine, a white precipitate, which, under the microscope, is
seen to consist of tufts of acicular crystals. —Concentrated nitric
acid does not color strychnine in the cold, and on heating only
turns it yellow.
The Physiological Text—A small frog placed in an ounce of
water to which ;}, of a grain of strychnine salt (acetate) is added,
is, in two or three hours, seized with tetanic spasms on the
slightest touch, and dies shortly afterward.
Strychnine has an intensely bitter taste. Cold water dissolves
only qygq part; yet this solution, even when largely diluted, is
distinctly bitter. Alcohol isa much better solvent, The salts
of the alkaloid are more soluble,
Brocrine, or Brucia, C,,H,.N,O,, 44,0, is an alkaloid accom-
panying strychnine in Nux Vomica and St. Ignatius’s bean to the
extent of about two percent. It is readily distinguished by the
intense red color produced when nitric acid is added toit. Jgasurine,
once supposed to to be a third alkaloid of nux yomica, has been
shown by Shenstone to be only a mixture of brucine and strychnine,
Curarine, CyH,.N,O, the active principle of the arrow-poison
termed evrari, urari, ourari, wouradli, or woorara, prepared from a
Strychnos, resembles strychnine in giving a color reaction on
oxidation, but the color is more permanent, Potassium iodide and
cyanoplatinate do not with curarine afford precipitates which
crystallize from alcohol like those of strychnine, Curarine, also,
is readily soluble in water, Unlike strychnine, curarine is reddened
by sulphuric acid; further it is not dissolved out by ether from an
acid or alkaline liquid. Curari appears to vary much in strength
and quality. It is probably a mixture of vegetable extracts,
Curine, C,.H,,NO,, also is said to be present,
Distinetion of Brucine from Morphine.—The red coloration pro-
duced by the action of nitric acid on brucine is distinguished from
that yielded with morphine, by the action of reducing agents
(such as stannous chloride, sodium thiosulphate or hydrosulphide),
which decolorize the morphine red, but change that of the brucine
to violet and green (Cotton). The solution of brucine in the
nitric acid should be heated to the boiling-point, diluted with
water, and the stannous chloride then added.
526 ORGANIC CHEMISTRY.
QUESTIONS AND EXERCISES.
What alkaloids are more or less characteristic of the different varieties
of cinchons bark? In what form do they occur ?}—By what method may
quinine sulphate be obtained ?—Give the characters of quinine sulphate.
—Describe the tests for quinine.—Show how quinidine or cinchouine sul-
phates may be proved to be present in commercial quinine sulphine,—
How are cinchonine and quinine distinguished from morphine ?—Whence
is strychnine obtained ?—Describe the process for the isolation of strych-
nine.—Give the characters of strychnine.—Describe the tests for strych-
nine.—By what reagent is bruecine distinguished from strychnine ?—
Distinguish between brucine and morphine.
ALKALOIDS OF LESS FREQUENT OCCURRENCE.
ACALYYPHINE is the well-marked alkaloid of Acalypha herb, or
Rupi, an expectorant used in place of senega. ,
ACONITINE, (Aconitina, U. 8. P.), or AcontTra, C,,H,NO,,,
is an alkaloid obtained from Aconite (Aconitum Napellus) root
(Aconitum, U.S. P.). The alkaloid itself is only slightly soluble in
water; it occurs in the plant in combination with a vegetable
acid, forming a soluble salt,
Preparation.—Dunstan's process for the preparation of aconitine
consists in dissolving out the alkaloid from the root with fusel
oil, and shaking the solution with sulphuric acid, which takes up
the aconitine; the acid is then freed from resin by shaking wi
chloroform, and the alkaloid liberated by ammonia in the presence
of ether, which dissolves it as soon as it is liberated. The aconi-
tine and benzaconine thus obtained are converted into hydrobro-
mides, and separated by fractional crystallization.
Properties. —Aconitine usually occurs as a white powder. It
has been obtained and studied in the crystalline state by Groves,
Wright, Williams, andothers. It is very slightly soluble in cold
water, more so in hot, and much more solable in alcohol, in ether,
and in chloroform. When rubbed on the skin, it causes a tingli
sensation, followed by prolonged numbness. The tooo
part of a grain on the tip of the tongue produces, after a minute
or so, & characteristic tingling sensation and numbness;
quantities rubbed into the skin causes numbness, Sulphuric acid
turns it of a yellowish and, afterward, dirty violet color.
According to Wright, who worked in conjunction with Groves
and Williams, Aconitum Napellus vields, chiefly, crystalline acon
CyH,NO,,, with some crystalline pseudaconitine, C,,H,,NO,,. Dun-
stan and Umney found, in addition to aconitine (O.H,NO
Dunstan and Ince), aconine, and an amorphous
nipelline or isaconitine, the salts of which are also amorphous.
yy
Aconitine is readily hydrolyzed into aconine, C,H
benzoic acid (Dunstan and Passmore). Aconine is ph
ALKALOIDS. 527
inert; benzaconine, C,,H,(C,H,CO)NO,,, is active but is not a
poison; while acetyl-benzaconine, or aconitine, C,,H,(CH,CO)
(C,H,CO)NO.,,, is a most powerful poison. The constitution of
aconine is not yet known. |
The tuberous roots of Aconitum Ferox and other species consti-
tute the bish or bith of India. It chiefly contains the variety of
aconitine termed psuedaconitine, Some of the aconitine of phar-
macy is pseudaconitine,
According to Paul and Kingzett, the alkaloid of Japanese
aconite has the formula C,H,.NO,, while Wright and Menke
state that the formula is Cy.H,.N,O,,, and name it japaconitine.
Aconitum heterophyllum, Atis or Atees Wakhma contains no aconi-
tine, but an alkaloid ateesine having the formula C,,H,,N,O,.
ARISTOLOCHINE, an alkaloid, and Aristolochin, a substance
having the physiological properties of aloin, also volatile oil, are
obtained from some of the species of Aristolochia, The official
drugs (Serpentaria, U. 8S. P.), are A. Serpentaria or Virginia
Snakeroot and A. reticulata (Texas serpentaria), —
ASPIDOSPERMINE, O©,,H,,N,O,, is an alkaloid of Quebracho
blanco bark (Fraude), Another alkaloid is quebrachine, C,,H,.N,O,
(Hesse). The latter chemist has isolated four other closely
related alkaloids; also two from Quebracho colorado bark.
ATROPINE or ArRopIA, C,,H,,.NO, (Afropina, U. 8. P.).—
This alkaloid was formerly considered to exist ready formed in
the Belladonna, or Deadly Nightshade ( Atropa Belladonna) (Bella-
donne: Folia; Belladonne Radix, U. 8. P.), as soluble acid atro-
pine malate. But the observations of Messrs Schering and the
researches of Will indicate that it is not atropine but an isomer
of atropine, namely hyoscyamine, which is the alkaloid chiefly
and often solely present, and that the treatment with alkali,
during the process of extraction, converts the hyoscyamine
into atropine, Hyoscyamine solutions rotate the plane of polari-
zation of light to the left; atropine has no optical rotary power.
Both possess the property of dilating the pupil of the eye. See
also HyOscYAMINE.
Preparation.—Atropine may be obtained by exhausting the root
with alcohol, precipitating the acid and some coloring-matter by
adding lime, filtering, adding sulphuric acid to form atropine sul-
phate (which is somewhat less liable to decomposition during sub-
sequent operations than the alkaloid itself), recovering most of the
alcohol by distillation, adding water to the residue, and evapo-
rating until the remaining alcohol is removed; solution of potassium
carbonate is then poured in until the liquid is nearly, but not quite,
neutral, whereby resinous matter is precipitated; the latter is fil-
tered off, excess of potassium carbonate then added, and the liber-
ated atropine dissolved out by shaking the liquid with chloroform.
The latter solution, having subsided, is separated, the chloroform
recovered by distillation, the residual atropine dissolved in warm
O28 ORGANIC CHEMISTRY,
alcohol, coloring-matter removed by digesting the ager oe
animal charcoal, and the solution filtered, evaporated, and
aside to deposit crystals,
Atropine is sparingly soluble in water, the liquid haying an
alkaline reaction, It is more soluble in aleohol and ether,
Tests.—With chlorauric acid, atropine solutions yield a yellow
precipitate. One drop of a dilute aqueous solution of atropine
(two grains to the ounce) powerfully dilates the pupil of a she
Baryta water decomposes atropine into tropine, C,H,.N
tropie acid, C,H,,O,, a molecule of water being abso Ee
C,,H.,.NO, + H,O = C,H,,NO + C,H,,0,.
Hence atropine would seem to be the tropine ester of tropic acid.
By heating tropine and tropic acid in sealed tubes Ladenburg has
succeeded in reproducing atropine, and has thereby raided
sible the synthesis of this alkaloid from its elements. Similarly
number of new alkaloids, known as tropeines and enalegete to
atropine, have been obtained by treating tropine with other acids,
One of these is homatropine (see below) which is the tropine carer
of mandelic acid. By removing the elements of water from
Ladenburg obtains fropidine, C,H,,N, closely related to ecgonine
(p. 532) and anhydro-ecgonine.
Tropine, when neutralized with mandelic acid, and the salt so-
formed heated with hydrochloric acid, yields homatropine, the
hydrobromide of which, C,,H,,NO,,H Br, is official (Homatropine
Hydrobromidum, U.S. P.). fomatropine hydrobromide is a white
crystalline powder or aggregation of minute trimetric eryst
soluble in 5.7 parts of cold water, and in 82.5 of alcohol. The
dilute aqueous solution powerfully dilates the pupil of the eye. A
2 percent, aqueous solution is not precipitated by the cautious
addition of solution of ammonia previously diluted with twice its
volume of water [distinction from atropine]. About a tenth of a
grain moistened with two minims of nitric acid and evaporated to
dryness on the water-bath yields a residue which is colored yellow
by an alcoholic solution of potassium hydroxide [distinetion from
atropine, hyoscine, and hyoscyamine]. If about a tenth of a grain
be dissolved in a little water and the solution be made alkaline
with ammonia and shaken with chloroform, the separated chloro-
form will leave on evaporation a residue which will turn
and finally brick-red when warmed with about fifteen sof
a solution of two grains of mercuric chloride in a hundred aaakee
of proof spirit; for Gerrard, Schweissinger, and Flickiger have
observed that homatropine (Ladenburg’s oxytoluyltropeine, which
is a physiologically similar but less powerful and therefore some-
times more useful alkaloid than atropine), like hyoseyamine and
atropine, has unusually powerful alkaline properties, precipitating
mercuric oxide from mercuric solutions, reddening phenelphtha-
ALKALOIDS. 529
lein, and, with the aid of heat, blackening calomel. No other
ordinary alkaloids are so powerfully alkaline,
In the so-called Japanese belladonna (Scopola oe there
oveurs scopoleine, an alkaloid resembling, but more powerful than,
atropine (Eykman); but Schmidt considers that only atropine,
hyoscyamine and hyoscine are present, See p. 536.
ions.—The alkaloid itself ( Atropina); itssulphate (Atro-
pine Sulphas), a white crystalline powder soluble in water (made
by neutralizing atropine with sulphuric acid); an extract (xtrac-
tum Belladonne Foliorum); a fluidextract (F'luidextractum Bella-
donwe Radicis); « liniment (Linimentum Belladonne); and an oint-
ment (Unguentum Belladonne),
The fluorescence of alkaline solutions of extract of belladonna
is caused by chrysatropie acid (Kunz), which appears to be identical
with the fluorescent scopoletin, C,,H,O,, found in Japanese bella-
donna by Eykman.
Baprrroxine.—Schroeder gives this name to a poisonous alka-
loid in Baptisia tinctoria, wild indigo, in which he also finds the
glucosides baptisin and baptin,
BEBERINE, BEBIRINE, or Brerrine, O,,H,,NO,, is an alkaloid
in the bark of Bebeeru, or Bibiru ( Nectandra Rodi).
Beberine sulphate, (O,,H,,NO,),, H,SO,, may be prepared by ex-
hausting the bark with water acidulated with sulphuric acid,con-
centrating, removing most of the acid by adding lime, filtering, pre-
cipituting the alkaloid with ammonia, filtering, drying, dissolving
in alcohol (in which some accompanying matters are insoluble),
recovering most of the alcohol by distillation, neutralizing with
dilute sulphuric acid, evaporating to dryness, dissolving the resid-
ual sulphate in water, evaporating to the consistence of a syrup,
spreading on glass plates, and drying the product at 140° F,
(60° C.). Thus obtained, it occurs in dark-brown translucent
scales, yellow when powdered, strongly bitter, soluble in water
and in aleohol. It is probably a mixture of beberine sulphate,
nectandrine sulphate, and other alkaloidal sulphates,
Tests, —Alkalies give a pale-yellow precipitate of beberine when
aided to an aqueous solution of a salt of the alkaloid; the precipi-
tate is soluble in ether. With potassium dichromate and sulphuric
acid, beberine gives a black resin, and with nitric acid a yellow
resin,
Busine, from the bark of Buxus sempervirens; pelosine, or
cisampeline, from the dried root (Pareira, U. 8, P.), of Chondro-
dendron tomentosum and of Ciasampelos Pareira; and paricine,
from a false Para cinchona-bark, are probably identical with beber-
ine (Flfickiger), | .
Nectandrine C,,H,.N.O,,4H,O).—Maclagan and Gamgee disecov-
ered this alkaloid in Bebeeru-wood, It differs'from beberine in
fusing when placed in boiling water, in being much less soluble in
ether, and in giving with concentrated sulphuric acid and black
4
d: ORGANIC CHEMISTRY.
manganese oxide a beautiful green and then a violet coloration.
They considered that two other alkaloids exist in Bebeeru-wood,
BERBERLNE, C,,H,,NQO,, isan alkaloid existing in several plants
of the natural order Berberidacew, in Calumba-root (Calumba,
U.S. P.), in the root of Coplia .7eeta or Mishmi Bitter, an Indian
tonic, in the dried stem of Coscinium fenestratum, and in many
other yellow woods, /7ydraatis canadensia or Golden Seal, contains
berberine, though a second alkaloid, hydrastine, related to narco-
tine and to papaverine, and even a third, are said to be present,
all, in Perkin’s opinion, benzene derivatives of iso-quinoline.
Hydrastine acid tartrate, C,,H,NO,, C,H,0,,4H,0, has been
vbtained in the crystalline form. The dried rhizome and rootlets
are official, (/7ydrastis, U. S. P.), and these are the source of the
Iuidextractum Hydrastis, U.S. P., and Tinetura Hoydrastia,
U.S. P. The root of Serberis vulgaris contains berberine and
oxyacanthine, C,H, NO,, (Riidel), as well as berbamine, C,H NO,
(Hesse). Xanthorrhiza apiifolia, an old Ameriean tonic, and,
upparently, Yanthorylon Fraxcineum, or Prickly Ash, also contain
berberine. The rhizome of Menispe rman Canadente, Yellow
Parilla, or Canadian Moonaseed, contains, according to Maisch, a
colorless alkaloid its well as berberine. The color of the tissues of
these plants is apparently due to berberine; for the alkaloid itself
is remarkable for its beautiful yellow color.
Preparation, —Berberine is readily extracted by boiling the raw
inauterial with water, evaporating the strained liquid to a soft
extract, digesting the residue in alcohol, recovering the alcohol
by distillation, boiling the residue with dilute sulphuric acid,
filtering and setting aside; berberine acid sulphate, C,H, NO,
Hi, SQ),, which is sparingly ‘soluble, separates out and may y be. puri-
fied by recrystallization from hot water, The alkaloid itself is
obtained by shaking lead hydroxide with a hot aqueous solution
of berberine acid sulphate (Procter).
Tests. —When a dilute solution of iodine and potassium iodide
is added to a solution of any salt of berberine in hot alcohol, lange
excess of iodine pane carefully avoided, brilliant green spangles
of a periodide, wth, -NO,I,, HI. are deposited, The reaction is
sufficiently lelicate to form, according to Perrins, an excellent
test for the presence of berberine, This iodo-compound polarize:
light, and has other analogies with he -‘rapathite.
Be rberine itself f is not official, but plants in which it oceurs are
used as medicinal agents in all parts of the world.
CAFPE ia or THEN INE, or GUARANINE (methyl-theobromine
(Caffeina, | U. 8. P.) O.H,N, Oy, Lg. — This alkaloid occurs in
Tea, 2 to 4.5 pe ree nt, ; ~ Coffee, ‘12 percent.; Maté or Paraguay
Tea, 0,2 to 2 perce nt. .; 6 fuarana, 5 percent, : and the Kola-nut,
0.5 perc ent. Irifusions and pre pan ations of ‘these vegetable pro-
ducts are used, chie fly as beverages, by thre - fourths of the human
race, Tt is rem: arkable that the instinct of man, even im his say-
ALKALOIDS. 531
age state, should have led him to select, as the basis of beverages
in such common use, just the four or five plants which out of many
thousands are the only ones, so far as we know, containing caf-
feine,
Caffeine is volatile. Considerable quantities may be collected
by condensing the vapors evolved during the roasting of coflee on
the large scale. A decoction of tea, from which astringent and
coloring-matters have been precipitated by solution of lead sub-
acetate, and which has then been acidulated with sulphuric acid
and well washed with chloroform, the latter fluid evaporated, and
eral gr dried at 100° C., yields an average of a little over 3
cae the tea) of anhydrous eaffeine. It may be crystallized
irae Asis ol or by sublimation. It forms salts with acids ( Caffeina
Citrata, U. 5, P., CyH,N,O,, C,H,O,) ; they are decomposed by
water.
Caffein Citrata Ejfervescens, U. 8. P., is made by mixing cal-
feine citrate with tartaric and citric acids, sodium bicarbonate, and
sugar, heating and stirring until the mixture assumes a granular
character.
Test. —Concentrated nitric acid, or, better, a mixture of potas:
sium chlorate and hydrochloric ‘acid, rapidly oxidizes caffeine,
forming compounds which with ammonia yield a beautiful pu rple-
red color, resembling the murexid obtained under similar circum-
stances from uric acid ; the oxidation must not be carried too far,
On boiling with potassium hydroxide caffeine yields methylamine,
The main physiological action of caffeine on the system is a stimu-
lating one especially affecting heart-muscle.
The commercial value of tea depends upon its appearance and
on the flayor and odor of the infusion, the percentage of caffeine
not varying much. China tea contains rather less caffeine and much
less astringent matter than tea from Ceylon or India, Tea infused
in boiling water for five minutes yields somewhat more than half
its caffeine to the fluid.
Graphie formula for Caffeine. —See p. 539.
Capsictne. —Felletér obtained from Capsicum-frnit (Capsteum,
U.S. P.), which when ground forms Cayenne Pepper, u volatile
alkaloid haying the smell of conine. Thresh has obtained crys-
talline hydrochloride and sulphate, The latter chemist has also
succeeded in isolating the active principle of capsicum, which he
has termed capaaicin, C,H,,,, a crystalline non-alkaloidal exces-
sively acrid substance. Its exact chemical character is not yet
made out, but Micko regards it as a nitrogen compound porsens-
ing a slightly acid phenolic character and gives it the » formula
Cw NO According to Thresh « similar very punge nt princi-
hip in ginger (ginge rol) and in grains of paradine (parudol),
ies probably isomeric with capaaicin, (See also Capricin, p.
—
6 C, gis NO, 00 ure in ‘Carica papaya, ,
552 ORGANIC CHEMISTRY.
CEPHAELINE, C,,H,NO,, is an alkaloid found in the root of
Cephatlis Ipecacuanha; about one-third of the total alkaloid in
the root is cephaéline, the remainder being principally emetine (a
third alkaloid is present in small quantity), Cephaéline is not
equal to emetine as an expectorant, but is superior as an emetic ;
it is rapidly decomposed when boiled with alcohol, See also EME-
TINE,
Cocaine, C,,H,,NO,, is an alkaloid of Erythroxrylon Coca, the
leaves of which act powerfully as a restorative to the human
system. The alkaloid itself and its hydrochloride are both official
(Cocaina, U. 8. P., and Cocaine Hydrochloridum, U, 8. P.).
Cocaine and its salts may be prepared by agitating with Lexie
spirit a concentrated, acidulated, aqueous extract of the leaves
made alkaline with sodium carbonate, well shaking the
spirit with acidulated water, treating the separated aci
with ether and excess of sodium carbonate, washing out the alka-
loid from the ether with water containing hydrochloric acid, and
finally evaporating the resulting aqueous solution of the hydro-
chloride to the crystallizing point, Cocaine may be precipitated
with ammonia and recrystallized from alcohol, ether, or warm
benzene, It melts at 204. 8° to 208,4° F, (96° to 98° C,). From this
pure cocaine the pure and very soluble hydrochloride may be pre-
pared by neutralizing with hydrochloric acid and crystallizing,
Prolonged contact of cocaine with hot water, acids, alkalies, or
even alcohol, is undesirable, as cocaine readily breaks up into ben-
zoyl-ecgonine, and wnethyl alcohol, C,,H,,NO,+H,0=O0,,H,NO,
+CH,OH, benzoyl-ecgonine afterward yielding ecgonine and
benzoic acid, C,,H,.NO,+ H,O = C,H,.NO, + CHO Other
bases occur in coca besides cocaine, Paul and Cownley also Giesel,
find cinnamyl-cocaine, Hesse finds two amorphous bases which he
names cocamine and eocaidine. Libermann finds several bases,
one of which is poisonous, namely, isafropyl-cocaine, O,,H,,NO,
(identical with Hesse’s cocamine), containing an isatropyl
in place of the benzoyl group in ordinary cocaine. All these
are easily hydrolyzed, yielding ecgonine ; the latter with benzoic
anhydride yields benzoyl-ecgonine ; and this with methyl iodide,
yields benzoyl-methyl ecgonine, or ordinary cocaine. A séries of
‘“‘cocaines’’ can be produced by introducing other groups into
ecgonine instead of the benzoyl groups.
Another alkaloid (benzeyl-pseudo-tropeine), yielding instead of
ecgonine a compound isomeric with tropine, also occurs in epoca
(Cuesel ; Liebermann), |
Cocaine hydrochloride occurs in colorless monoclinic
soluble in water, chloroform, alcohol, amyl aleohol ; very 8 |
in ether ; not readil y decomp sed even when boiled in water, The
free alkaloid is readily decomposed by water, especially when the
solution iswarmed, The solution in water has a bitter taste ; gives
a purple precipitate with permanganutes ; and a white preci
i;
i
ALKALOIDS. 533
with ammonia. Its solution produces on the tongue a tingling
sensation followed by numbness. The aqueous solution dilates
the pupil of the eye. It gives no color to cold concentrated acids,
but chars with hot sulphuric acid. Evaporated to dryness on a
water-bath with nitric acid, and treated with alcoholic potash, it
develops an odor resembling peppermint. Besides its action as a
restorative when taken internally, cocaine brought into contact
with the mucous membrane of the eye, mouth, throat, ete., or
when injected, produces local anwsthesia, According to Squibb,
good coca leaves yield 0.5 percent. of cocaine. Cocaine may be
detected in presence of other alkaloids by giving a yellow precipi-
tate of cocaine chromate with either potassium chromate or chromic
acid in presence of free hydrochloric acid,
COLCHICINE, (Colchicina, U.S. P.), the active principle of
Colchicum autumnale (Colchict Cormus, U, 8S. P. 3 Colehici Semen,
U.8.P.), is said to be an alkaloid, although SOIne investigators think
it has more of the characters of a neutral substance. Hertel states
that ebullition with acidulated water converts it into colehiceine
and methyl alcohol Giesel says it may be crystallized from
chloroform, and sie the following formule for it and its deriva-
tive; colchicine, C,H »(OCH,)NO, ; colchiceine, C,,H,,(OH)NO,,
The most active medicinal preparation is an extract ‘made from the
Sresh seeds by digestion i in large volumes of alcohol and subsequent
digestion of the marc in hot water. The extracts left on evaporat-
ing the two liquids separately are to be carefully mixed (Mols).
dood ab Contra, CONYLIA, Keon or CicuTINE, ©,H,,.N,
pyl-piperidine, C, H, (C,H). This alkaloid isa vola-
tile tle liquid, occuring in the fruit (€ pie U.S. P.), of Hemlock
(conium maculatum) i in combination with an acid (malic?), Accord-
ing to Petit its boiling-point is 170° C., and its density 0. 846. It
forms crystalline salts,
Preparation.—Coniine may be obtained by distilling hemlock-
fruit with water rendered slightly alkaline with sodium or potassium
hydroxide or by similarly treating the fresh juice of the leaves,
The crude alkaloid is a yellow oily liquid, floating on the water
that distils over; by redistillation it i is obtained colorless and trans-
parent. Coniine may also be obtained from Conium by the offi-
cial assay process.
The salts of coniine are odorless, but when moistened with wae.
tion of an alkali yield the alkaloid, the strong odor of which,
once recalling hemlock, is characteristic.
Tents. —Sulphuric acid turns coniine purplish-red, changing to
olive-green; nitric acid a blood-red; chlorauric acid produces A fl
yellowish-white precipitate, chloroplatinic acid no precipitate in
aqueous solutions,
Hemlock alao contains methyl bree. (o .H,, Je HN (Kekulé
and Von Planta), and of Bik A,, NO, T he. latter by dehy-
dration yields a base. H,, ,N.
534 ORGANIC CHEMISTRY.
According to Schiff, coniine, isomeric, at least, with the natural
alkaloid may be produced artificially by action of ammonia on
butyric aldehyde and destructive distillation of the resulting com-
pound. Ladenburg has produced coniine, identical with the
natural alkaloid, from a-picoline. Coniine may now therefore be
said to be a product of organic synthesis, producible from its
elements.
CoryDALINE, C,,H,,NO,, occurs together with several other
alkaloids in the tater of Corydalia cava, in which it was dis-
covered by Wackenroder in 1826, It forms colorless prismatic
erystals which are practically insoluble in cold water, readily solu-
ble in ether und chloroform, and sparingly soluble in alcohol,
The crystals melt at 134,5° C. Both crystals and solutions
quickly assume a yellow color on exposure to light or on heating.
The alkaloid forms a number of salts, some of which crystal-
lize well.
CusPARInE, C,,H,,NO,, with eusparidine, C,H ,NO,, and gali-
pine, C,,H,,NO,, are. alkaloids occurring in the bark ‘of CGalipea
eusparia, OF true Angostura Bark. The bitter principle, angoa-
turin, is not an alkaloid,
CyTIsINE or ULEXINE, C,,H,,N,O, is an alkaloid found in labur-
num and furze, and is identical with sophorine, from Sophora
fomentoaa,
DATURINE.—See Hyoscy AMINE.
DELPHINE, or DELPHININE and DELPHINOIDINE are the
poisonous alkaloid of Stavesacre (Delphinium Staphisagria), The
powdered seeds of the plant are employed to kill the pedien/i of
animals, The seeds (Staphisrgria, U. 8, P.), contain about 25
percent. of oil.
Diramine, C\.H).NO, (Jobst and Hesse), is an alkaloid of
‘« Dita,’’* or bark of Echites acholaris or ‘tetonda scholaria a
reputed febrifuge. Others are echitamine or ditaine and echife-
nine, Oberlin and Schlagdenhauffen state that the allied A/stonia
conatricta (the bark of which is said to have advantages over the
hop as a dietetic bitter) contains a crystalline alkaloid, alstonine
and uncrystallizable a/etonicine, Alstonine seems to be allied to
strychnine,
Du raced: g. — See H YOsScYAMINE,
EMETINE, ' H,,NO,.—This alkaloid is one of the active prin-
c siple 4 of the Ss Cephatlis apecaennne ([pecacuanha, U. &. P. ).
It occurs to the e xtent of 1 to 2 2 pe rcent, in the root (less in the
stems) in combination with ipecacuanhic acid. The nitrate is
pec ‘uliarly slightly ‘solub le ‘in wate rT (Le fort). In Pulris Ipecacuanhe
et Opii, U.S.P., or Dover’s Pow der (Powdered Ipecacuanmha, 1 part;
Powdered ‘Ophimn, L part; and Sugar of Milk, 8 parts), minute
division of the ac tive ingre “lie nts is | rromote “il by prolonged tritu-
ration. (Fluide atractum Ipec ae uanhe, U.S. P. ), contains 1.75
Cin, of the alk: Woids of the root in. 100 Ce Jpecucuanha Wine
ALKALOIDS. 535
( Vinum Ipecacuanhe, U. 8. P.), is a mixture of 1 part by volume
of Muidextractum Ipecacuanhe with one of alcohol and eight of
white wine, Cephaéline (4 percent. in Brazilian and 1} percent,
in Columbian, according to Paul and Cownley) and small quantities
of a third alkaloid, are also found in ipecacuanha.
The Indian substitute for ipecacuanha is the dried leaf of Tylo-
phora asthmatica, Its active principle has not been satisfactorily
determined, but would seem to be the alkaloid tylophorine
(Hooper).
GELSEMINE, C,,H,,N,O,.—This is one of the alkaloids of (el-
semmiuim nitidum, or Carolina Yellow Jasmine (Gelsemium,U. 8. P.),
in the tissues of which plant the ge/seminic acid of Wormley, and
resenlin, C\.H,.O, the fluorescent glucoside of the Horse Chestnut
and of many other plants, are also present. Like strychnine,
gelsemine is not apparently affected by concentrated sulphuric
acid. Nitric acid does not color it. A mixture of sulphuric acid
and black manganese oxide colors it a crimson red, changing to
green. In (elsemium elegans, Crow finds an allied alkaloid which
does not resist the action of sulphuric acid. (elxeminine,
C,,H,,N,O,, is another Gelsemium alkaloid, said to be more pow-
erful than gelsemine,
GRINDELINE is the name given by Fischer to a bitter porvealnae
alkaloid he extracted from Grindelia (robusta), U, 8. P, The
plant also contains a resin and a volatile oil,
HoMATROPINE.—Ave ATROPINE.
HYDRASTINE.—See BERBERINE.
Hyoscrne or Scorpotamine.—Besides hyoscvyamine, Laden-
burg finds in henbane some /yoacine, € ‘HNO, ; identical with
scopolamine from Seopola atropoides and 5. carniolica. Hyoscine
hydrobromide is official | Hyoscinee Eh ydrobromidum, U.S. P. ).
Hyoscyamine, C,,H,.NO,, occurs in the leaves Niger Hyosey-
nia, Uv, 5. P. and thas purts of Henbane (Hyoseyamus), Bella-
donna, Stramonium, and various — «Bpee ies of Beopola; “nlso
(Dymond) in Lettuce. It forms bri liant colorless needles. Its
salts alsoare crystalline, Its effect: on the eye a is similar to that of
atropine. The researches | of Laden mburg show that hyose yamine
is the tropate of an alkaloid isome! ric with | tropin e, The hydro-
bromide and sulphate are official (Hyose yamine Hydrobr ‘omidum
and Hyoscyamine Sulphas, U ‘ 8. P. ). (See ATROPINE. )
The alkaloids: in Datura Stramonium, or Thorn: apple (Stramo-
nium, U, S, P.), Dhatura the leaves of Datura fastuosa and PD.
Metel, and the seeds of Datura fastuosa, and i in Duboisia Myopo-
roides, were forme rly sup posed to be distinct alkaloids, called
respectively Daturine and Duboisine, but are ide wn tic al with hye =
eyamine, which is isomeric with. atropine (L ade nburg). According
to Schmidt, the alk: aloid of Duboisia » mye pporoides is sometimes
hyoscyamine and sometimes hyoscine or scopolamine. Paeudo-
hyoseyamine, ©,,H,,NO,, also occurs: in the latter plant, Bees
556 ORGANIC CHEMISTRY,
which sip from the flowers of stramonium are said to deposit
poisonous honey.
Hyoscyamine melts when heated to between 108° and 109° C.,
and then is soon converted into atropine, Its solutions in alcohol
orether are stable, but the presence of a very minute amount of
fixed caustic alkali, or of alkali-metal carbonate, causes its com-
plete conversion into atropine. With chlorauric acid its salts
give a yellow crystalline precipitate, soluble in boiling water
acidulated with hydrochloric acid, and again deposited, as the
solution cools, in brilliant, yolden-y ellow scales,
JABORANDINE and JABORINE,—See PILOCARPINE,
JERVINE, C,,H,,NO,, occurs in Veratrum album, White Helle-
bore, and VF. viride, American White Hellebore, ( Veratrum,
U. 5. P.). Its saltsare much less soluble in water than those of
veratrine. According to Bullock, Veratrum viride contains another
alkaloid—veratroidine; and, according to Mitchell, Veratrum
album aiso contains another alkaloid which he terms veratralbine,
Tobien gives the tormula of Jervine as C,,H,N,O,, and of vera-
troidine as C,H,,N,O,,, or C,,H,,NO,. ‘According to Wright,
Veratrum album ‘contains jervine, C,.H,NO, ; PUNO. and
C,,H,,.NO,; rubijervine C,H,.NO,; veratralbine, ( sNO,; and
traces of veratrine, C,H NO The same author Wind. Petatrue
viride to contain jervine, pseudojervi ine, cevadine, C.H_NO, |
rubijervine and traces of veratrine and veratralbine. Behkechen
finds jervine, pseudojervine, and yeratroidine, while Salzberger,
besides jervine, rubijervine, and pseudojervine, finds protovera-
trine, C,,H,,NO,,, and protoveratridine, C,,H,,NO, Salzberger
confirms Wright a and Luff’s formula for jervine.
LoneLIne.—A yolatile fluid alkaloid first isolated from the
dried flowering herb Lobelia inflata ( Lobelia, U.S. P.), by Proctor.
In the pure state it is inodorous, impure it smells slightly, but
mixed with ammonia emits a strong and characteristic smell of
the plant. With acids it forms salts. A solid alkaloid is said to
be present.
LUPULINE is stated by Greismayer to be a liquid volatile alka-
loid contained in the Hop, Humudus Lupulus (Humulus, U.S. P.).
The powdered trictromes of the plant are official (Lupulinum,
U. Ss. P. \,
NECTANDRINE.— ‘See BERBERINE.
Nicotine, C,,H,.N,.—This is « volatile liquid alkaloid, form-
ing the powerful active principle of Tobacco \ Nicotiana Tubacum),
nicotine malate and citrate being the forms in which it occurs in
the leaf. Its odor is characteristic; like conine, it yields a pre
cipitate with chlorauric acid, but, unlike that alkaloid, its aqueous
'The name of Green ITeliehore is sometimes applied ta this droog, but
properly be ‘longs to Helleborns viridis (see “ Helleborin’ p SOD), wh ch be
used medicinally in some parts of Europe. — Hanbury.
ALKALOIDS. 537
solutions yield a yellowish white precipitate with chloroplantic
acid, It is not official, It is also contained in /Pituri, a
drug “chewed by the natives of some parts of Australia as a
suimulant narcotic,’’ though, according to Liversedge, the latter
alkaloid may have the formula C,,H,,N,,.
PELLETIERINE. — Pelletierine tannate (Pelletierinen Tannas,
U.S. P.), is the name given to the mixture of the tannates of
punicine, iso-punicine, methyl-punicine and pseudo-punicine,
obtained from Punica Granatum (Granatum, U. 8. P.),
PHYSOSTIGMINE, or ESERINE (from vere, the name of the ordeal
ison of the bean at Calabar), C,.H,,.N,O,.—An alkaloid of melt-
ing-point 106° C., obtained from the Calabar Bean (Physostigma,
U.S. P.), the seed of Physostiyma venenosum (Jobst and Messe),
by dissolving the ethereal extract in water, filtering, adding sodium
bicarbonate, shaking the mixture with ether, and evaporating the
ethereal liquid, Extractum Physostiqmatis, Tinetura Physostigmatis,
Physostigmine Salicylas and Physostigmine Sulphas are official.
A trace of it powerfully contracts the pupil of the eye and is
applied in the form of disks; a small quantity is highly poisonous.
Eber states that physostigmine, by action of acids, ete., takes up
the elements of water and becomes eseridine, C,,H,,N,O,, melting-
point 132° C., an alkaloid one-sixth the strength of physostigmine
and occurring to some extent in the Calabar bean itself. Ehren-
berg finds, also, eseramine, C,,H,.N,O, (melting-point 238° C,,
physiologically inactive), and gets esero/ine as a derivative of
physostigmine,
Prnocarrine, C,,H,,N,O,, is apparently, the active principle
of the diaphoretic and sialogogue Pi/ocarpus Jaborandi (Pilocarpua,
U. 8. P.). The occurrence of an alkaloid in this plant was first
announced by Hardy, followed almost immediately by Byasson.
A erystalline nitrate and hydrochloride were first obtained by
Gerrard. The leaves also yield an essential oil, a terpene C,,H,,
(Hardy). Harnack and Meyer state that the formula for pilo-
carpine is C,,H,,.N,O,, and that its effects resemble those of nico-
tine; also that jaborandi yields another alkaloid, jaborine,
C,H N,O,, which is allied to atropine in its effects. Pilocar-
pine Hy: rochloridum and Pilocarpine Nitras are officinl, Pilo-
carpine has a faintly bitter taste, and is soluble in water and in
aleohol. Concentrated sulphuric acid forms with it a yellowish
aolution which, on the addition of potassium dichromate, gradu-
ally acquires an emerald-green color. It leaves no ash when
burned with free access of air. It causes contraction of the pupil
of the eye. Merck states that a third alkaloid, pilocarpidine,
CyoH,,N,0,, ia present in jaborandi. Harnack thinks that pilo-
carpine is probably « methyl derivative of pilocarpidine; Merck
has shown that the base to which Harnack gave the name pilo-
earpidine does not yield pilocarpine by methylization, nnd that
the isomer obtained by this operation differs from pilocarpine in
038 ORGANIC CHEMISTRY.
being insoluble in water. Merck, confirmed by Hardy and Cal-
mels, states that jaborine is derived from pilocarpine by natural
oxidation, while pilocarpidine by oxidation yields jaboridine,
O,,H,,.N,O,. The latter chemists have obtained pilocarpine arti-
ficially, 3-pyridyl-a-lactic acid being converted into pilocarpidine,
and this into pilocarpine,
Preerine, (Piperina, U. S. P.), C,,H,NO,, is a feebly basic
alkaloid oceurring in White, Black (Piper, U. 5. P.), and Long
Pepper ( Chavica officinarum, Mign.), and in Cubeb Pepper ( Cubeba,
U. 8. P.), associated with volatile oil and resin; to these sub-
stances the odor, flavor, and acridity aredue, Piperine is obtained
on boiling white pepper with alcohol, and evaporating the liquid
with solution of potassium hydroxide, which retains the resin.
Recrystallized from aleohol, piperine forms colorless prisms fusible
at 212° F, (100° C.), With acids and certain metallic compounds
it forms salts, and distilled with concentrated alkali yields piperi-
dine, C,H,,N, an alkaloid of strongly marked properties, and
piperic acid, C,\,H,,0,. Piperidine is interesting as being one of
the alkaloids that has been obtained artificially by Ladenburg.
It is hexahydro-pyridine, and is obtained by the hydrogenization
of pyridine (by the action of sodium in presence of alcohol).
Johnstone finds it in long pepper and in ordinary pepper, more
especially in the husk. According to Buchheim the amorphous
resin of the peppers is similar in constitution to piperine, alkalies
breaking it up into piperidine and chavicie acid. Pyrethrin is also
said to decompose in an analogous manner. The piperine of
cubeb pepper is not to be confounded with eudebin, a neutral con-
stituent and having the formula C,H,,O,. Piperidine acid tar-
trate, a crystalline salt easily soluble in water, is a good solvent
for urie acid.
SANGUINARINE is the alkaloid of Blood Root (Sanguinaria
canadensis, Sanguinaria, U. 8. P.). ts salts are red. Kénig and
Tietz find five distinct alkaloids in the root of sanguinaria, viz,
chelerythrine, C,,H,,NO,; sanguinarine, CH,NO,; a-homoocheli-
donine, C,,H,,NO, ; 8-homochelidonine, C,, H,,NO, ; and protopine,
C,,H,,NO,. Protopine was found in opium by Hesse, It also
occurs in Celandine (Chelidonium, U. 8. P.), and is identical with
macleyine obtained by Eyckmann from Mae/eya cordata,
ScorpoLAMINE. —See HYOSCINE.
SoLANINE.—This alkaloid exists in the Woody Nightshade, or
Bitter-sweet (Solanum du/camare). [t occurs also in the shoots,
and in minute amount in ‘the skins, of the tubers of the Potato
(Solanum tuberosum), This alkaloid is only slightly soluble in
coloration,
into a sugar and so/an idine, iG eissle r finds dulcamarin, Cc H,,
a glucoside, to be the bitter constituent of Solanum duloamene,
ALKALOIDS. 539
Sulphuric acid and alcohol, or either selenic acid or sodium sele-
nite and sulphuric acid, colors solanine or solanidine a dark red,
_ _ Sparreiwe, O,,H,,N,, is a poisonous volatile alkaloid occurring
_ in Broom-tops (Seoparing, U.S. P.). Its discoverer, Stenhouse,
considers that the diuretic principle of broom is Scoparin, C,,H,,O,,,
4 non-poisonous substance, sparingly soluble in cold water. Mills
has obtained ethyl! sparteine, C,,H,.C,H,N,, and diethyl-sparteine
C,,H,(C,H,),N,. Apparently sparteine contains two pyridine
nuclei. Sparteinw Sulphas, U. 8. P., has the formula ek oe
H,S0,,5H,0,
STILLINGINE.—Bichy states that this alkaloid is present in
Stillingia sylvatica or Queen's Root, (Stillingia, U. 8. P.).
TAXINE, C,.H,NO,,? is an alkaloid occurring in the yew.
THEINE.— ce CAFFEINE.
THEOBROMINE, C,H,N,O,, is an alkaloid occurring in cocoa, the
seed of Theobroma Cacan, to the extentof 1 to 2 percent, Accord-
ing to Schmidt, some catleine is present also. Theobromine is also
in Kola-nut (Heckel and Schlagdenhauffen), The caffeine in
cacao, kola, and tea, is said to occur normally as a glucoside,
which would explain why it is only partially extracted by chloro-
form from a mixture either of these substances with lime.
Relations between Caffeine and Theobromine.—Both caffeine and
theobromine are methy! derivatives of xanthine, C,H,N,O, (belong-
ing to the uric acid group, uric acid having the formula C,H,N,O,).
Caffeine, or trimethylxanthine has been obtained synthetically
from uric acid by Fischer and Ach. Theobromine, or dimethyl-
xanthine may be obtained from a silver derivative of xanthine by
the action of methyl iodide; and caffeine (methyltheobromine)
may be obtained by heating theobromine silver with methyl iodide
(Strecker). Theophyllin, isomeric with theobromine, was obtained
by Kossel from tea extract.
HN—CO
Lape
ol C—NH
I
Uricacid Xanthine
CH,N—CH
a
OC C—NH
“co
CH,N—C=N
Theobromitie or dimethytx anihine
CH,N—CH
Ay") bee
OC O—NCH,
| >co
CH,N— C=N
Cn ite! ne or tr imet hylxant hi ne
540 ORGANIC CHEMISTRY.
TRIGONELLINE, C,H,NO,, H,O.—Jahns states that this alka-
loid, as well as one identical wit choline, are present in the seeds |
of fanugreck or fenugreek ( Trigonella Fanumgracum) much use :
in veterinary medicine, and in some varieties of cattle food
curry powder,
TROPINE, —See ATROPINE,
TYLOPHORINE,— See EMETINE,
VASICINE, occurring as adhatodate, has been shown by Hooper
to be the active principle of the leaves of Adhatoda vasica, or Ru. ‘
(Hind. ) or Bakas (Beng.) or Vasaka (Sanskrit), an official Ind
expectorant (Adhatoda, B. P. Add. 1900),
VERATRINE, or VERATRIA, (Veratrina, U. 8. P. CoH NO at
—This alkaloid occurs in Cevadilla, the seeds of Schanoca
officinale, of A. Gray Seep Asagrea officinalis by ny
Veratrum officinale by Schlecht. It is also said to occur in the
of Sarracenia purpurea. According to Weigelin, cevadilla con-
tains two isomeric varieties of veratrine, the one soluble the ¢
insoluble in water. He says there are also present sabadilline aad
sabatrine. Commercial veratrine contains the two latter alkaloids:
(Weigelin). A mere trace of veratrine brought into contact with the
mucous membrane of the nose causes violent fits of speesinig:
These alkaloids, and those from the different species of Veratrum,
are evidently very closely allied. Wright and Luff, by the se of
tartaric acid, a solvent less likely than the aia acids to decom-
pose alkaloids, extract from cevadilla, ae vei at
cevadine, Cy, ile and cevadilline, C\H,NO, A
Merck, cevadilla contains two clkaleids, "sabadine hee ee
sabadinine, C,,H,,.NO,.
The alkaloid may be extracted by exhausting the disin
grated cevadilla-seeds with alcohol recovering most of the
by distillation, pouring the residue into water, by which much
resin is precipitated, filtering, and precipitating the veratrine
from the aqueous solution by addition of ammonia. It is purt-
fied by washing with water, solution in dilute hy
acid, decolorization of the liquid by animal charcoal, pitas
tion ‘by ammonia, washing and drying. Bosetti states that itis a
mixture of crystalline cevadine, insoluble in water, with an —
amorphous isomeric soluble alkaloid, veratridine. According to |
Lissauer their phy siological action is ide ntical,
Oleatum Veratrine and Unc guentum Veratrine are official,
eee wees eee
RY SCALE CoMPOUNDS.
. “Zhe scale. Heat the ash with nitric
_ solution of ammonium molybdate in
No YELLOW PRECIPITATE.
Precipitate some of the aqueous
lution with potash, filter, and add
h a portion of the filtrate a slight
Waexcess of nitric acid, divide into two
m@nrts. To one add barium chloride
pt. = sulphuric acid). To the other
d silver nitrate (ppt. = hydrochloric
id). Neutralize another portion of
be potash filtrate with nitric acid
d add silver nitrate.
PRECIPITATE PRECIPITATE
RAY TO BLACK. WHITE.
Add very little Citric acid gives
mmonia (not suf- | imperfect or no
‘ient to dissolve | mirror. Calcium
ae we whole precip- | chloride and lime |
‘a ate) and heat. ! do not precipitate |
k silver mirror = | citric acid in the
til rtarte acid, cold, but upon
Caleium chlo- boiling (if solu-
de and lime ppt. | tion be sufficient-
neutral solution | ly concentrated)
At oconcentrated) ; precipitation — oc-
FH the cold, the | curs.
t ‘Zecip. redissolv-
Pe on boiling.
id
@ contamination).
FEERIC SALT.
POTASSIUM.
SoDIUM.
INORGANIC
BASES
solution of scale with potash
and test vapor for ammonia.
Filter and dissolve precipi-
tate in hydrochloric acid,
and test the solution for
tron by ferrocyanide, thio-
cyanate, etc.
Potassium and Sodium.—
Ignite a small quantity of
the scale, and moisten the
residue with water. Test
moistened residue with lit-
mus-paper. If alkaline, ex-
amine for potassium and
sodium by the color im-
parted to flame, and for
potassium by the platinum
test.
4 Confirm Turtaric or Citric Acid.—To slightly ac idified potash filtrate
BP. -ald ammonia in slight excess and considerable quantity of ammo-
gum and calcium chlorides. Tartrates are precipitated completely
~ ‘ the cold with agitation and rest for about ten minutes.% To the
I Dlution (or filtrate, if tartrates are present) add three volumes of
i Qpeohol (90 per cent.), when citrates are precipitated. If sulphates
J ave been found, disregard 3 a slight precipitate with the alcohol.
Compiled by A. SENIER.
AMMONIUM (often as
ally converted into pyrophosphoric). ;
‘ Amination). ;
- ~ Ammonium.—Boil aqueous —Boil aqueous
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542 ORGANIC CHEMISTRY.
QUESTIONS AND EXERCISES.
How is aconitine prepared ?—Give the strengths of the official prepara-
tions of the atropine,—Describe the properties of atropine.—Whiat is the
active principle of stramonium ?—Mention official preparations contain-
ing cocaine and beberine.—Give the characters of beberine.—lu what
does nectandrine differ from beberine ?—Mention the characteristies of
conine.—What are the active principles of ipecacuanha?—Name the
alkaloid of tobacco.—Give the properties of the alkaloid of Cnlabar bean.
—What are the sources of piperine ?—Whence is caffeine obtained ; what
is its relation to theobromine ?—Describe the preparation of veratrine.—
State the properties of veratrine.
Here the student is recommended to qualitatively analyze
unnamed specimens ( previously selected for him) of the free and
combined vegan ie substances included in the appended Tables
land 2
SOME IMPORTANT PROXIMATE CONSTITUENTS OF
ANIMAL AND VEGETABLE ORGANISMS.
Prorerp PRINCIPLES, OR ALBUMINOIDS,
Albumin,—<Agitate thoroughly, some white of egg with
water, and strain off the liquid from the flocculent membra-
nous insoluble matter. The white of a hen’s egg to 100Ce,
of water forms the “ Albumin Test Solution” of the U. S, P.
Test.—Heat « portion of this solution of albumin to the boiling-
point; the albumin becomes inseluble, separating in clots or
coagula of characteristic appearance,
Other Reactions.—Add to smal] quantities of aqueous solu-
tion of albumin solutions of mercuric chloride, silver nitrate,
cupric sulphate, lead acetate, alum, stannic chloride, or any
of the salts of the heavy metals; the various salts not onh
coagulate, but form insoluble compounds with, albumin.
Hence the v: alue of an eg ‘gx as a temporary antidote in cases of
poisoning by m: any met: allic salts, its administration retarding
the absorption of the poison wotil the stomach-pump or other
means can be applied. Sulphuric, nitric, and hydrochlorie
acids coagulate albumin ; the coagulum is slowly re-dissol ved
by aid of. he: at, ‘a brow! n, yellow, or ‘ purplish- red color being
duced. Neither : acetic . tartar ic, nor organic acids generally,
except pleric and gallotannic, coagulate tlhumin. Alkalies
ANIMAL SUBSTANCES. 545
prevent the precipitation of albumin, and hence, in testing for
albumin when only a trace is suspected to be present, it is
well to make the fluid very faintly acid with acetic acid.
Excess of acid acts like alkali in preventing coagulation but
not so powerfully ; in one case the absence of coagulation is
due to the formation of acid albumin and in the other to the
formation of alkali albumin both of which are products formed
by the partial disintegration of the proteid molecule and com-
bination of the portions of the disintegrated molecule with the
alkali or acid,
The products so formed are soluble even on boiling and
hence no coagulation occurs when dilute solutions of albumin
are boiled in presence of excess of alkali or acid.
Yolk or Yelk af Eqg contains 16 percent, of proteid, and 32 per-
cent, of fatty matter, The greater part of the proteid is in com-
bination either with nucleins, among which the iron-containing
nucleo-proteid is of importance as a hemoglobin producer ; or
with the phosphorized fats or lecithins, forming lecith-albumins
or vitellins,
Albumin is met with in large quantity in the serum of blood,
in smaller quantity in chyle and lymph, and in the vaseular
tissues generally. It is not a normal constituent of saliva, gastric
juice, bile, or mucus, but may occur during inflammation, It is
found in the urine and fwces only in certain diseased states of the
system.
Albumin is a highly complex substance, and its formula and
chemical constitution are at present unknown. Egg albumin has
been shown by direct determinations of osmotic pressure to possess
in solution a molecular weight of about 10,000, while serum
albumin has a molecular weight of about 50,000. Solutions of
albumin, probably on account of the large size of the molecule,
do not diffuse through parchment paper and in this way may be
dialyzed from admixed crystalloids (i,¢., substances which separate
from solution in crystalline form, as contrasted with colloids, or
glue-like substances, which do not crystallize). This method of
separation is often of practical importance in medico-legal anal-
yses,
Egg albumin (and, to some extent, blood albumin) is largely
used by calico-printers as a vehicle for colors, serving also, when
dry, as a glaze, Curriers prize egg-oil for softening leather.
Fibrin, Casein, Legumin.
Fibrin is the substance formed when blood or lymph undergoes
coagulation. It is produced in the blood in the process of coagu-
=
O44 ORGANIC CHEMISTRY.
lation from a very unstable compound termed jibrinogen. The
fibrinogen is attacked after the blood is shed by a ferment which
is formed from the disintegrating white corpuscles. These corpus-
cles yield a substance which combines with the calcium salts present
in the fluid, to form a soluble ferment termed ¢irombosin or fibrin
ferment. The thrombosin then acts upon the fibrinogen and cou-
verts it into insoluble fibrin in the form of long threads of substance
which bind the red corpuscles into a solid clot. Fibrin may be
obtained by whipping fresh blood with a bundle of twigs, separating
the adherent fibres, and washing in water until free from red cor-
puscles, It may best be kept in equal parts of glycerin and water,
Average Composition of Blood.—In human blood the moist
corpuscles and plasma make up nearly equal ty thus A.
Schmidt found in blood Telit by venesection, 52.1 parts of
plasma and 47.9 parts of corpuscles. The plasma contains
approximately 8 to 10 percent. of coagulable proteids of which
only about 0.2 to 0.4 percent. is fibrinogen, 3 to 4 percent. globu-
lin, and 5 to 6 percent. albumin. In addition there are about
0.6 percent. of other organic constituents, including about 0.15
percent, of glucose which forms the circulating carbohydrate of
of the body. The inorganic salts amount to about 0.8 percent.,
the salt present in largest amount (0.6 percent.) is sodium chloride,
Coseinogen occurs in Cow’s Milk to the extent of about4
cent., dissolved by a trace of salt of an alkali-metal. Its soluti
does not spontaneously coagulate, like that of fibrin, nor by heat
like albumin; but acids cause its precipitation from milk in the
form of a curd containing the fat globules (butter) previously
suspended in the milk, a clear yellow liquid (or whey) remaining.
Caseinogen, like fibrinogen, is capable of being changed into an
insoluble form by the action of an unorganized ferment or enzyme.
The insoluble form is termed casein, and is produced in the manu-
facture of cheese. The ferment is called rennin, or chymosin, and
is contained in rennet, which is an extract prepared commercial
from the salted and dried mucous membrane of the fourth
of the calf, but it is also present in the gastric mucous membrane
not only of all mammals, but in birds and fishes. Similar milk-
coagulating enzymes are found in the pancreatic juices, and in
the juices of the stems and leaves of many plants, As in the case of
fibrinogen, calcium salts are necessary in order that coagulation
may occur,
A rennet extract may be prepared by extracting the salted
mucous membrane with ten times its volume of a 5 percent. solu-
tion of sodium chloride (to which 1 part in 10,000 of boric acid
may be added as. a ‘preserv: ative) for about seven days at roo
temperature. The fluid should be stirred up occasionally,
an extract will coagulate 10,000 to 50,000 times its own volume
of fresh milk.
MILK. 545
» AVERAGE COMPposITION oF 1000 PARTS oF MILE.
| | | oud | Casein |
eer, Water. constit- and ex- | Sugar, Butter.
ents. tractive.
Salts.
! —————
Human . | 1-030 to 1.034 | 870 130 27 60 40)
Cow's . | 1.030t0 1.035 | 877 | 123 40 46 30
Leeds put the average composition of human milk at 2 percent.
of proteids, 7 percent, of milk sugar, 4 percent. of fat, and 0.2
percent, of ash.
Specific gravity alone, as taken by the form of hydrometer
termed a /actometer, or even by more delicate means, is of little
value as an indication of the richness of milk, the butter and the
other solids exerting an influence in opposite directions, Good
cow's milk affords from 10 to 12 percent. volume of cream, and 3
to 34 percent. of butter. The water of milk seldom varies more
than from 87 to 88 percent., and the solid constituents from 13 to
12, Indeed, excluding its butter, milk is curiously regular in
composition. The non-fatty solids in the mixed milk of a herd
or dairy of healthy cows is almost a constant quantity, namely,
9.3 percent. A lower proportion of non-fatty solids in a sample
of milk points to the addition of water, Thus, supposing that
100 grains of a specimen of milk, evaporated to dryness, and all
butter extracted from the residue (previously disintegrated by help
of 1 or 2 parts of dried gypsum, or the dried infusorial earth
termed Aieselguhr) by means of ether, yielded a non-fatty residue
of 7,44 grains, the specimen would probably be four-fifths milk and
one-fifth water.’ Occasionally, under exceptional circumstances,
a sample of genuine milk may be somewhat poorer than that from a
healthy herd. For legal purposes, somewhat varying standards
have been adopted for different places, about 9 percent. by weight
of non-fatty solids and 3 percent. of butter-fat being usually re-
quired, Only in the rare cases of milk containing an wousually
large proportion of butter-fat could any milk yielding less than 9
percent. of non-fatty solids be regarded as genuine, And, again,
no milk would be considered genuine, under such standards, if it
yielded less than 3 percent. of fat, not even in the rare case of its
containing un unusually large proportion of real non-fatty milk-
solids. Cows in bad condition might yield milk below these
standards ; but it could scarcely be considered to be normal, or
better fitted for food than milk watered after leaving the cow. LI,
‘Soxhlet determines fat by noting the specific gravity of an ethereal
solution and then referring to tables showing percentage of fat in ethereal
solutions of varyiny specific gravity.
ao
ORGANIC CHEMISTRY.
therefore, a sample of milk is to be regarded as genuine, a stand-
ard of 9 percent, of non-futty solids and 8 percent, of fut cannot
be regarded as too high,
When examined under the microscope, milk presents a charac-
teristic field of minute highly refractive globules consisting of the
suspended fatty matter, which yields on separation the cream, or,
when the globules are broken by agitation and coalesced together
as in churning, the butter. The fat is fluid at the normal temper-
ature of the animal, and remains so until the milk is well agitated
by churning or otherwi ise, or until the milk is frozen,
Legumin, or vegetable casein, is found in most leguminous seeds,
and in sweet and bitter almonds, Peas contain about 25 percent.
of legumin.
Vegetable albumin is contained in many plant-juices, and is
deposited in flocculi on heating such liquids. Vegetable fibrin is
the name given by Liebig and Dumas to that portion of the gluten
of wheat which is insoluble in alcohol and ether. Apongine, the
organic matter of sponge, appear to bea proteid.
The various proteids differ somewhat in their elementary com-
position, and the results experimentally obtained by different com-
petent observers even in the case of the same proteid (or, indeed,
different analyses of the same proteid by the same observer) s
enough variation to preclude the possibility of deducing
formule of any importance. The mean composition of wicks
is, however, of some physiological importance, especially in the
ease Of the nitrogen, a determination of which is often employed
48 a measure of total quantity of proteid, the total nitrogen —
determined and this multiplied by 6.25, on the assum
proteid on the average contains 16 percent, of nitrogen, ' ‘Silow.
ing figures give the limits of variation in each of the elements
found by different observers : carbon, 50 to 55 percent, ; hydro-
gen, 6.8 to 7.3 percent. ; nitrogen 15 to 18 percent, ; oxygen, 21
to 24 percent. ; sulphur, 0.3 to 2 percent.
Proteids are found also in combination with other organic groups
such as carbohydrates, fats, phosphorized fats, and nucleins, so
forming the vast class of compound proteids. Examples are hamo-
globin, the iron-containing coloring-matter of the blood ; ; the nu-
cleins which are proteids combined with ‘cei tna
bodies ; the nucleo-proteids which are abundant in cell nuclei
are compounds of organic nitrogenous substances (also con
phosphorus) called nucleins, with proteids ; the eith-albumins of
egg-yolk already referred to: ; and casein which consists of proteid
united to a phosphorus-containing radical,
*roteids are divided, according to their solubility in water and
certain saline solutions into “albumens,” or “ aanee ead
lins,"* ‘albumoses, P48 he ptones,’’ ete, Some globulins albu-
moses form most virulent poisons when injected direety inte the
blood stream ; to this class of substances belong the poison of most
~
GELATIN-PRODUCING SUBSTANCES. 547
venomous reptiles, and also certain vegetable poisons such as that
contained in the seeds of Abrus precatorius (Jequerity). The albu-
moses of ordinary digestion are similarly poisonous when injected
directly into the blood stream. All these poisonous substances
are, however, harmless when swallowed, being modified as they are
absorbed from the intestines, and so converted into innocuous pro-
ducts,
Musk (Moschus, U, 5. P.), ‘the dried secretion from the
preputial follicles of Moschus moschiferus” (the Musk-deer), is a
mixture of albuminoid, fatty, and other animal matters with a
volatile odorous substance of unknown composition. ‘* Artificial
Musk,’’ a synthetical compound having an odor resembling in
quality and power that of natural musk, ts trinitro-tertiary-butyl-
toluene, C,HCH,(NO,),C(CH,),.
GELATIN-PRODUCING SUBSTANCES,
These nitrogenous substances, collectively known as codlagens
(glue-producing), differ, chemically, from the proteids in contain-
ing less carbon and sulphur and more nitrogen, They are con-
tained in certain animal tissues, and on boiling with water yielda
solution which has the remarkable property of solidifying ton jelly
on cooling, In the process of boiling with water the collagen
becomes hydrated and yields the gelatin or g/ufin which is hence
called the hydrate of collagen. When gelatin is heated to 130° C.
the reverse change occurs and collagen is re-formed. -The tendons,
ligaments, bones, skin and serous membranes afford gelatin proper ;
the cartilage give chondrin, which differs from gelatin in composi-
tion and in being precipitated by vegetable acids, alum, and lead
acetate, or subacetate. The purest source of gelatin is isinglass,
which is the swimming-bladder or sound of various species of Aci-
penser, Linn., prepared and cut into shreds. Small quantities
are more easily disintegrated by a file than a knife, A recently
prepared 2 percent. aqueous solution forms the Gelatin Test Solu-
tion, U.S. P. Gelatin (Gelatinum, U. 8. P.), is officially defined
as ‘* the purified air-dried product of the hydrolysis of certain ani-
mal tissues, as akin, ligaments and bones, by treating with boil-
ing water,” (Glue is an impure variety of gelatin, made from the
trimmings of hides ; size is glue of inferior tenacity, prepared from
the parings of parchment and thin skins. ‘‘ Among the varieties
of gelatin derived from different tissues and from the same sources
at different ages, much diversity exists as to the firmness and other
characters of the solid formed on the cooling of the solutions.
The differences between isinglass, size, and glue, in this respect are
familiarly known, and afford good examples of the varieties called
weak and strong, or low and high gelatin, The differences are some-
times ascribed to the quantities of water combined in each case
with the pure or anhydrous gelatin, part of which water seems to
o48 ORGANIC CHEMISTRY,
be intimately united with the gelatin ; for no artificial addition of
water to glue would give it the character of size, nor would any
abstraction of water from isinglass or size convert it into the hard
dry substance of glue. But such a change is effected in the gradual
process of nutrition of the tissues; for, as a general rule, the tis-
sues of an old animal yield a much firmer or stronger jelly than
the corresponding parts of a young animal of the same species,”
(Kirke’s Physiology. )
Gelatin is precipitated from aqueous solution by alcohol, mer-
curic chloride, chloroplatinic acid, tannic acid, and many of the
usual proteid precipitants. Pure glutin or gelatin does not give
Millon’s reaction, that is, a white precipitate turning red on
boiling, when treated with the mixed nitrates of mercury (Millon’s
reagent), This reaction is characteristic of all true proteids, The
failure of this reaction in the case of gelatin indicates the absence
of the tyrosin group from the gelatin moleule, Aqueous solution
of gelatin is not, like that of albumin, coagulated by heat, nor is it
precipitated by ‘acids. By prolonged ebullition its gelatinizing
power is destroyed.
PEPsIN.
Pepsin (from rérrw, pepto, I digest) is an enzyme existing in
the gastric juice, which is secreted by the parietal cells of the
gastric glands, The hydrochloric acid which aecompanies it in
the gastric secretion is formed by a different type of cell in the
glands called the oxyntic cells, Pepsin is only active in an acid
medium. The enzyme exists in the gland cells in a pr
form called pepsinogen, and the active pepsin is formed from this
substance in the act of secretion.
Pepsin may be prepared in the following manner:—The
cleansed mucous membrane of the stomach (of the hog, sheep, or
calf, killed fasting) is scraped, and the scrapings are macerated in
cold water for twelve hours; the pepsin in the strained liquid is
then precipitated by lead acetate, the deposit washed onee or
twice by decantation, hydrogen sulphide passed through the mix-
ture of the deposit with a little water to remoye the whole of the
lead, and the filtered liquid evaporated to dryness at a tempera-
ture ‘not exceeding 105° F. (40.5° C.),
Pepsin (Pepsinum, U. 8. P. ), is officially described as a proteo-
lytic ferment or enzyme obtained from the glandular layer of the
fresh stomach of the hog and proved to be capable of se
not less than 3000 times its own weight of freshly coagulated and
disintegrated e eer albumin, /
It is obtained as ‘lustrous white, pale yellow yi yellow
transparent or translucent scales or grains, or a fine white 0
cream-colored powder, free from any offensive odor, and haying a
BILE. 549
slightly acid or saline taste. It should be not more than slightly
hygenopic."’ The official assay of pepsin is based on the capacity
of the preparation for digesting coagulated egg albumin,
The solvent action of pepsin and hydrochloric acid on proteids,
leads to the formation of a complex mixture of acid albumin,
albumoses, and peptones.
The albumoses are an intermediate stage in the conversion of
agg proteitl into peptones.
he product obtained by the artificial action of pepsin on
various forms of proteid is known commercially as peptone.
Any form of asa may be digested as above deseribed with
pepsin and hydrochloric acid, and various commercial peptones
are so prepared from white of egg, minced meat, or blood fibrin,
Papain is a proteolytic enzyme contained in the leaves of the
papaw tree (Carica papaya) which has been utilized as an arti-
ficial digestive agent for proteids, .
PANCREATIC ENZYMES,
The pancreas (sweetbread) secretes a colorless fluid of alkaline
reaction which contains enzymes acting respectively upon each of
the three classes of foodstufls, viz., proteolytic enzyme called
trypsin which converts proteids into albumoses and peptones in
neutral or alkaline solution; an amylolytic enzyme called amylopsin
or pancreatic diastase which converts starches into dextrins and
maltose; and steatolytic or fat-splitting enzyme called steapsin or
lipase which hydrolyzes fats into fatty acids and glycerin. Active
extracts may be prepared by extracting the gland, which ought to
be allowed to stand for some hours before extraction, with water
faintly acidulated with acetic acid, with dilute alcohol (1 in 4),
with equal parts of glycerin and water, or with lime water and
glycerin, The official pancreatin (/’anecreatinum, U. 8. P.), is
a cream-colored amorphous powder, usually obtained from the
fresh pancreas of the hog or the ox. Besides the three enzymes
named above it contains a fourth enzyme, myopain.
Ferratin ia an organic iron compound which has been isolated
from pigs’ liver, and is regarded as a normal constituent of the
organs of the animal body, in the tissues of which it is stored up
as a reserve material for the formation of blood,
BILe.
The gall or bile, (Fel Bovia, U.S. P,), of the ox (Boe taurus,
Linn.), evaporated to one-third of its bulk and freed from mucus
by agitating with an equal volume of alcohol in which mucus is
insoluble, setting aside for three or four days, filtering and evap-
orating, yields the official Purified Oxgall (/e/ Bovis Purificatum,
580 ORGANIC CHEMISTRY.
U.S. P.): the latter has the appearance of a yellowish-green soft
resin, but is chiefly composed of two crystalline substances; the —
one is termed sodium taurocholate, NaC,,H,,NO,S, the other is
sodium glycocholate, NaC,.H,,.NO,. Both taurocholates and glyco-
cholates readily undergo hydrolysis, the former yielding cholte or
cholalie acid, HC,,HyO,, and taurine, C,A,NOS, the latter
cholalic acid and glycine, glycocoll, or amido-ac acid,
CH,(NH,)COOH, asoluble crystalline substance having interesting
physiological relations, for it is obtainable from gelatin (hence the
name glycocoll or sugar of gelatin, from yAvmic, glueis, sweet, and
xéAda, kolla, glue) and from hippuric acid. |
Choline (oA), cholé, bile), C,H,,NO,, is an alkaloid originally
found in bile, where it is derived trom decomposition of lecithin,
but it occurs in the brain, ete., in cod-liver oil, and in plants—
ergot, Indian hemp, ipecacuanha, ete.
Tests for Bile-—The presence of bile ina liquid such as
urine, may be detected by the following test :
1. The inside of a porcelain capsule is wetted with the
suspected liquid, one or two crystals of cane-sugar are added,
and then a few drops of concentrated sulphuric acid.
The capsule is then gently warmed, care being taken not
to char the conteuts, when a reddish coloration develops,
rapidly changing to violet. This test is known as Pettenkofer’s
test, and depends upon the interaction between furfurol and
the bile salts, The furfurol is produced by the action of the
sulphurie acid on the cane-sugar.
2. Gmelin’s test is given by the bile pigments, and is ear-
ried out by pouring the bilecontaining fluid u fuming
nitric acid in a test-tube, when colored rings form at the
junction of the two fluids, a green ring forming aboye, which
lower down passes into blue and then into brown near the
acid, Gmelin’s test may also be made by wetting a piece of
filter-paper with the suspected fluid and then adding a drop
of fuming nitric acid, which becomes surrounded by caleel
rings as described above.
QUESTIONS AND EXERCISES.
Tn what form is albumin familiar ?—Name the chief tests for albumin ?
Whiy is the administration of albumin usefolin cases of poiso ning ?—
Mention the points of difference between yolk and white o pera
COLORING-MATTERS. 551
what sources other than egg may albumin be obtained ?—In what respects
does fibrin differ from albumin ?—Enumerate the chief constituents of
blood.—How may fibrin be obtained from blood ?—State the difference
between casein, fibrin, and albumin.—What are the relations of cream,
butter, curds and whey, and cheese, to milk ?—Describe the microscopic
appearance of blood and inilk.—How much cream should be obtained from
good milk ?—What is the percentage of water in genuine milk ?—Naime
the sources of vegetable albumin and vegetable casein.—Give the per-
centage of nitrogen in albuminoid substances.—Describe the chemical
nature of musk.—In what liethe peculiarities of gelatin-producing snb-
stances ’—To what extent do isinglass, glue, and size differ ?—Whence
is pepsin obtained, and how prepared t—Give the proximate constituents
of bile—What are the tests for bile ?
COLORING-MATTERS,
The animal, vegetable, and mineral kingdoms abound in more
or less brilliantly colored natural substances which are frequently
employed as dyes or pigments, while art has richly supplemented
the number of such natural coloring-matters. In the following
paragraphs some of the more useful of these materials are enumer-
ated under their respective colors;
YELLOwW.—Chrome yellow occurs in more than a dozen shades
(sce Lead chromate). 2. Fustie or yellow wood, the wood of Rhus
Colinus, is colored by fisetin, its leaves by myricetin (Perkin), 8.
Gamboge (see p. 479). 4. Ochre is met with of many tinta, under
the names of yellow ochre, gold gellow, gold earth or ochre, yellow
sienna, Chinese yellow. It is chiefly a mixture of iron oxyhydrox-
ides with nlumina and Jime, It has been used from the earliest
times. 5, Orpiment and King's yellow are arsenic sulphides.
6. Persian berries, or Avignon grains, contain a yellow principle
termed rhamnin and other crystalline bodies; they are the product
of two or three species of Rhamnaus. 7. Purree, piuri or Indian
yellow, is said to owe its color toa magnesium compound of exran-
thin, C\gH,,0),. 8. Quercitron ia the bark of Quereus tinctoria ;
it contains the yellow glucoside, quercitron, C,H,.O,,. 9. Rhu-
barb (see Chrysophanic acid). 10, Saffron, the dried stigma and
part of the style of Crocus sativus, yields polychroite or crocin, an
orange-red glucoside, Kayser gives the formula of crocin as
0,). Any admixture
sulphate, or similar
powder, with saffron, is readily detected by placing a amal! sample
in a glass of warm water and stirring,when insoluble powder is
deposited. Incinerated with free access of air, dried saffron does
not deflagrate, and yields about 7 percent. of ash, 11. Turmeric,
the rhizome of Curcuma longa, owes its yellow color to cureumin,
a substance which crystallizes from alcohol in prisms. Jackson
and Menke state that curcumin is an acid, and that its formula is
5)2 COLORING-MATTERS.
H,C,,H,,0,. Apparently two yellow pence are present. The
co oring-mattera of turmeric are readily dissolved by chloroform,
while those of saffron, mustard, or the best East-Indian rhubarb
are not, On this fact methods of detecting turmeric in those sub-
stances have been founded. 12. Weld Ssieme? te contains a
durable yellow matter termed duteolin (C,,H,,O . Pierie or
carbazotic acid (p, 435) is avery powerlul ratloe ee “14. Dried
and powdered carrots yield to carbon bisulphide a yellow coloring-
matter, “‘carrotin,’’ which is obtained on evaporating the solvent.
It is said to be used in coloring butter,
Rep.—1. Alkanet, the root of Alkanna finctoria, Tausch,
Anchusa tinctoria, Desf, yields anchusin or alkannin, C,,H,,O,, a
resinoid substance soluble in oils and fat. 2, Annatto, arnatlo, or
arnotto, a paste prepared by evaporating strained aqueous extract
of the seeds of Bixa Orellana, contains bixin, C,,H,,O,, an orange-
red, and oredlin, a yellow, principle, 8. Brazil- wed ( Corsalpinia
Brasiliensis) furnishes brezilin, C\H,,O,, the basis of several
lakes; sappan-wood contains either resitin OF & closely allied sub-
stance, sappanin ; Camwood, from Baphia nitida, contains a simi-
lar substance, perhaps santalin, 4. € ‘innabar, Chinese red, Ver-
milion, or Paris red, is mercuric sulphide. It isa eS ancient
red pigment. 5. Chrome-red is a lead oxychromate, Cochin-
ead (see p. 328). 7. Madder, the root of Rubia tinetoria, pees
and treated with sulphuric acid and acidulated water to effect the
removal of earthy and other inert matters, furnishes a residual
powder termed garancin, Garancin yields to pure water adizarin,
C\,H,O,, the red, neutral, crystallizable coloring-matter of madder,
Alizarin does not exist ready formed in the plant, but is derived,
by fermentation, from a glucoside, termed rubianie acid, Alizarin °
is now largely ‘produced artificially from anthracene, one of the
solid constituents of coal-tar (see p. 411). 8. Mulberry-juice con-
tains a violet-red coloring-matter which has not been chemi
examined. 9. Red lead (see p, 222). This, and the following
red ochre, are very ancient red coloring-matters. 10. Red tran
aride, of shades varying from lightto brown-red, is found native.
The common names of it are Armenian bole, Berlin red, coleothar,
English red, red ochre, burnt ochre, red earth, terra di
mineral purple, -stone-red, and Indian red, 11. Red Saunders
(Santalum Rubrum, , U.S. P.), or Red sandal-wood or barwood, the
billets and chips of the heart-wood of Pterocarpus santalinus, owes
its c volor to santalin, CG «HO a crystalline substance possessing
an acid character. Crystalline _pteroe ‘arpin, C, oH Oy and homo-
pterocarpin, Cc, LH, Oy, are also present (Cazeneuve), 12. pit
Petals from Pa apaver . Rheas, contain a red coloring principle
has not yet been isolated in astate of purity. The author has
sought for ‘morphine in large quantities of the petals, but could
not find a trace of that alkaloid. 13. Red-Rose Petals (Rosa Gal-
lica, U. 8. P.), and those of the Cabbage-Rose, also yield a red
BLUE. 553
substance which has not been analyzed. 14, Safflower, dyer’s
saffron, or bastard saffron, the Horets of Carthamus finctorius, eon-
tains an unimportant yellow dye, and 5 percent. of earthamin,
C,,H,,0,, an uncrystallizable red dye, the pigment of the old ping
saucers. Carthamin seems to possess acid characters, and (like
silicic acid and other substances) to be soluble in water for a cer-
tain time after liberation from its alkaline solution; for fabrics are
dyed with safflower by immersion in a bath made of an infusion
in dilute alkali neutralized by citric acid immediately before use,
the carthamin probably penetrating the cells and vessels of the
fibres in a soluble form, there becoming insoluble and imprisoned,
and thus giving permanent color to the wool, silk, or other mate-
rial. Mixed with French chalk, carthamin is used as a cosmetic
under the name of vegetable rouge—carmine being animal rouge,
and red iron oxide the mineral rouge. 15, Lac-dyeis a cheap form
of cochineal, and is also yielded by the species of Coccus whose
resinous excretion constitutes /ac (stiek-lac, seed-lac, or shell-lae,
according to its condition as gathered off the twigs on which it is
deposited, or as roughly separated from impurities in seed-like
powder or lumps, or as melted and squeezed through bags into
shell-like pieces), 16, Logwood (Himmatoxrylon, U.S. P.), con-
tains a yellow substance, hamatorylin, C,,H,,O,, H,O(or 8H,0), to
which any medicinal usefulness of the wood is perhaps due, and
which, under the influence of air and alkali or ferments, assumes
a very intense red color—heamatein. Under the joint influence of
ammonia and air hematoxylin yields greenish-violet iridescent
scales of this hamatein, C,,H,,0,,3H,0. 17. Red enamel colors,
for glass-staining and ceramic operations, are produced either by
cuprous silicate or purple of Cassius (p, 199).
BLuE.—Cobalt oxide precipitated in combination or admixture
with alumina or calcium phosphate forms Thénard'’s blue, cobalt-
blue, Hojfner’s blue, and cobaltie ultramarine. 2. Smalt, Sarony
blue, or King’s blue is rough cobalt glass in fine powder (p. 141).
Copper-blue, mountain-blue, and English’ or Hambro’ blue wre
chiefly copper oxycarbonates. 4, Indigo, ©,,11,,N,O,, is a blue
coloring-matter deposited when infusion of’ various species of
Indigofera is exposed to air and slight warmth. Under these cir-
cumstances, indican, a yellow, transparent, amorphous substance,
soluble in water, breaks up into indigo, which is insoluble and
falls as a sediment, and a sugar termed indig/uein. The indigo is
collected, drained, pressed, and dried. By the action of reducing
agents indigo is converted into soluble colorless indigogen, reduced
indigo, or indigo white: 1 part of powdered indigo, 2 of ferrous
sulphate, 3 of calcium hydroxide, and 200 of water, shaken
together and set aside in a well-closed bottle, yield this color/ess
indigo, CyH),N,O.. Linen or cotton yarn, or calico, dipped into
such a solution and exposed to air, becomes blue, deposition of
insoluble indigo-blue occurring within the cells and vessels of the
COLORING-MATTERS,
fibre. This operation is readily performed on a small scale, and
forms an illustration of a characteristic feature of the art of dyeing
—namely, the introduction of soluble coloring-matter into a fabric
by permeation of the walls of its cellular and vascular tissue, and
the imprisonment of that coloring-matter within the cells and ves-
sels by conversion into a solid and insoluble form [see p. 148).
Pure indigo, or tndigotin, may be obtained in beautiful needles by
spreading a paste of indigo and plaster-of-Paris on a tin plate, and
when quite dry placing a lamp underneath, moving the latter from
place to place as the indigo sublimes and condenses on the surface
of the plaster. It may also be obtained in crystals by gently boil-
ing finely powdered indigo with aniline, filtering while hot, and
setting aside; these crystals may be washed with alcohol. Hot
paraffin may be employed instead of aniline. Indigo may be pro-
duced artificially. Toluene, from coal-tar, was, by Perkin’s pro-
cess, converted into cinnamic acid, this into a nitro-derivative,
and this again into orthonitrophenylpropiolic acid. From the
latter, alkali and grape sugar deposited crystalline indigo (Baeyer),
Other methods have since been devised. 5, Litmus, lichen-blue,
turnsole, orchil or archil, and cudbear, are products of the action
of air and alkalies on certain colorless principles, as orein,
C,H,(OH),CH,, derived from different species of lichen—Roceella,
Variolaria, and Leeanora, 6. Prussian blue (p. 165) and Tirn-
bulls blue (p. 164) are met with under the names of Zr
Louisa, Saxon, Paris, or Berlin blue. 7. Ultramarine, a very ol
blue pigment, formerly obtained from the rare mineral, /apis
lazuli, is now cheaply made on a large scale by roasting a mixture
of fine white clay, sodium carbonate, sulphur, and chareoal or
rosin. Its constitution is not well made out, Acids decompose it,
hydrogen sulphide eseaping.
PURPLE, — See MUREXID, p. 346,
GREEN.—1, Cwpro-arsenical green pigments (p, 184), Most
of the ancient greens contain copper carbonate. The original
emerald green was u hydrous chromium oxide, but cupric aceto-
arsenite is now sold under this name. 2, Chlorophyll, leaf-green,
or chromu/le, is the substance to which the leaves of plants owe
their green color. It is resinoid, soluble in alcohol and ether,
insoluble in water, and, on decomposition, yields a yellow and a
blue substance (the phyllocyanin and phylloxanthin of Frémy
and of Schunck). Recent researches tend to show that the
chlorophyll obtained from different plants varies in composition.
5. Sap-qgreen, bueckthorn-, vegetable-, or bladder-green, known also
as Chinese green, or /okas, is obtained by evaporating to dryness
a mixture of lime and the juice of the berries of buckthorn
(Rhamnus catharticus), Tt is soluble in water, slightly soluble in
uleohol, and insoluble in ether and oils. 4. Green is
made by a process similar to that for blue ultramarine, 6. Mix-
tures of the blue and yellow pigments and dyes are common sources
BROWN; BLACK; WIITE; ANILINE. 555
of green colors, 6. Glass and earthenware are colored green by
chromic oxide and cupric oxide,
Brown.—lL. Umber, sienna, or chestaut-brown is found native,
By the action of heat it is darkened in tint, and is then known as
burnt umber, It is a mixture of ferric oxide, silica, and alumina,
2. Sepia is a dried fluid from the inkbag of cuttle-fishes (Sepiade’);
by its ejection into adjacent water the animal obtains opportunity
of escape from enemies, Chtlechu (p, 342) furnishes a brown
coloring-matter,
BLack.—l, Blacklead (p. 297), bone-black (p. 297) or ivory-
black, and lamp-black, the latter a deposited soot from the incom-
plete combustion of rosin and tar, are varieties of carbon, 2.
Burnt sugar, or caramel (p. 485). 3. Jndian ink is usually a
dried mixture of fine lamp-black and size or thin glue. 4, Black
writing imk consists essentially of iron tannates and gallates
suspended in water containing a little gum in solution. 5, Printer's
ink is well-boiled linseed or other oil, mixed with good lamp-
black, vermilion, or other pigment. 6. lack dyes are frequently
of the same nature as ink. 7. The old ‘‘pigmentum nigrum’ of
black feathers, such as those of the common rook, of dark hair,
and probably also of the skin of the negro, is, doubtless, the
black substance which remains undissolved when black feathers
are digested for some time in dilute sulphuric acid. It is said to
have the formula C,,H,.N,O, (Hodgkinson and Sorby).
Waite PiagMents.—1. Chalk or whiting (pp. 112, 117). 2.
French chalk, steatite, tale (Taleum, U. 8. P.), or soapatone, is
largely magnesium silicate, 3. Heavy white (p. 109), 4, Pearl-
white (p. 229). 5. Plaster-of-Paria (p. 112). 6. Starch (p, 487).
7. White lead or Cremnitz white (p, 223). 8. Aine while or
Chinese white (p. 184). 9. ‘ Constant’’ white is barium tungstate.
10, Toilet fake white is bismuth oxynitrate; artists’ flake white is
a form of dry white lead (p, 228), 11, Tin and zinc oxides and
calcium phosphate are employed for giving a white opacity to
glass.
ANILINE Cotors, Chal-tar colors.— Within the past few years
nearly every shade of color seen in the animal and vegetable king-
doms has been successfully imitated by certain dyes and pigments
primarily derived from a mineral, coal, Coal distilled for gas
furnishes tar or gas-tar. Coal-tar contains some aniline; but
especially it contains a liquid convertible into aniline, namely,
benzene (C,H,), first discovered by Faraday in compressed oil-
gas. From aniline, by oxidation, Runge obtained the violet-
color reaction, the substance producing which Perkin afterward
studied and isolated, and manufactured under the name of mawve.
Anitine-red ( fuchsine, magenta or rosaniline), anitine-yellow, ani-
line-green, aniline-blue, and, in short, aniline-dyes, lakes, and pig-
ments of the most varied hue are now common articles of trade.
Their application has revolutionized the art of the dyer and color-
GENERAL QUALITATIVE ANALYSIS.
printer. Certain of these coloring matters, for examples tetra-
methylthionine hydrochloride, (Methy/thionina: #f woridum,
U. 8. P.), methylene blue, are used in medicine. Some of the
coal-tar colors are not ‘‘aniline’’ colors, being derived from
naphthalene, phthalic acid, phenol, ete.
QUESTIONS AND EXERCISES.
Mention the chief yellow coloring-matters and deseribe their chemical
nature.—What is annatto?—Name the colorific constituent of madder.—
Can it be made artificially ? —State the source of litmus.—Distinguish
between Prussian blue and Turnbull's blue; how are they manufac-
tured ?—How are they affected by acids ?—Describe the chemical nature
of the coloring principle of leaves.—By what agents is glass colored
green ?—Whence is sepia obtained ?—Describe the chemistry of black
ink.—Write a few sentences on aniline colors.
QUALITATIVE ANALYSIS OF SUBSTANCES
HAVING UNKNOWN PROPERTIES.
Substances are presented to the analyst in one of the three
forms in which all matter exists—namely, solid, liquid, or gaseous;
and they may contain animal or vegetable as well as mineral
matter,
The method of analysis in the case of solid mineral bodies has
been described on pp, 354 to 362.
Solid animal or vegetable substances (or mixtures of these with
mineral bodies) may be indefinite and beyond the grasp of
chemistry, or definite and quite within the range of proximate
qualitative organic analysis, The presence of such substances is
indicated in the preliminary examination of a solid (pp. 354 to
357) by charring and other characters, If no charring occurs,
and no volatile liquid is expelled by heat, the absence of such
matter is indicated. But if organic matter is present, an endeavor
is made to ascertain its precise character. The analyst’s knowl-
edge of the history of the substance, or the circumstances under
which it comes into his hands, will probably afford a clue to its
nature, and enable him to search directly for its proximate eon-
stituents. If no such information is at hand, the action of solvents
may be employed, as likely to afford indication of the general, if
not of the precise, nature of the substance, Water, alcohol, ether,
chloroform, carbon bisulphide, each hot and cold, may in turn be
agitated with the substance ; each extract may then be filtered,
& portion of the filtrate evaporated, at first partially, setting the
product aside for the deposition of crystals, etc., and afterward
to dryness ; and any deposit or residue may be examined with
and without the aid of a microscope. Other portions of the fil-
GENERAL QUALITATIVE ANALYSIS. 557
trate may be treated with acids, alkalies, and solutions of such
metallic salts as are commonly used as group-reagents for acid
radicals (p. 852). The action of alkalies as well as acids, dilute
and concentrated, hot and cold, may also be tried on the solid
substance itself, and colors, odors, and, in short, any effect what-
ever, be duly noted. A portion of the substance should also be
burnt in an open porcelain crucible until no carbon remains, and
the ash, ifany, be examined ; its amount und nature may afford
information leading to the identification of the substance,
The foregoing experiments having been carefully performed,
and all results entered in the note-book, a little reflection will
possibly lead to recognition, or may suggest further direct experi-
ments or confirmatory tests, or will, at least, have pointed to the
absence of a very large number of possible substances, and thus
have restricted the area of inquiry to comparatively narrow limits.
The success attainable in qualitative proximate organic analysis
by the medical or pharmaceutical student will of course largely
depend on the thoroughness with which the operator has prose-
cuted his study of practical chemistry generally; but it will be
considerably affected also by the extent to which he has cultivated
the art of observation, and the opportunities he has had of acquiring
a knowledge of the appearance, uses, and common properties of
definite chemical substances, and of articles of food, drink, and
medicine. ‘The most successfu] of several good analysts will be the
one who has most common sense and most experience,
The pharmaceutical student, who has probably already had
some years of experience in pharmacy, occupies an unusually
fuvorable position for prosecuting the proximate analysis of organic
and inorganic substances, or, at all events, of that large proportion
of such substances met with in the domain of hygiene and phar-
macy. Many substances he will identify at sight, or by aid of o
lens, or after ‘applying some simple physical or chemical test, Nor
should he find much difficulty, after reaching the present point
of practical study, in deciding whether the solid substance under
examination belongs to the class of organic acids, organic salts of
metallic radicals, alkaloids, alkaloidal salts, amylaceous matter,
gums, saccharine substances, glucosides, albuminoid matters, futs,
soups, resins, coloring-matters, etc. For instance, the pharma-
ceutical student will find less difficulty than the general student
in successfully analyzing a substance occurring in ‘* seales,”’
because he has experience of the appearances of compounds
commonly produced in that form, and because, even if the
appearance is new to him, he knows what kind of substances
most readily lend themselves to production in that form. While
the genera] student is testing generally, and proceeding cautiously,
or searching for genera! information in books of reference, the
pharmaceutical or medical student has incinerated some of the
material, noticed whether or not the ash is red (iron) and strongly
558 GENERAL QUALITATIVE ANALYSIS,
alkaline (potassium), treated more of the material with an alkali
(for ammonium), added excess of ammonia, and examined the
precipitate (for cinchonine or quinine) or shaken up the alkaline
liquid successively with ether and chloroform, and tested the
residue of these decanted and evaporated solvents (quinine, beber-
ine, strychnine), aud examined the aqueous solution of the
material, or one of the filtered alkaline liquids, in the usual way
for acid radicals (citric, tartaric, sulphuric, hypophosphorous nee:
Or he has modified his methods to include search for some "
preparation’’ which his special knowledge tells him has been
newly introduced to, or is rare in, pharmacy.
In the case of liquids, the solvents as well as the dissolved matters
claim attention. A few drops are evaporated to dryness on plati-
num foil to ascertain if solid matter of any kind is present; the
liquid is tested with red and blue litmus-paper, to ascertain if free
alkalies, free acids, or neither are present; a few drops are heated
in a test-tube and the odor of any vapor noticed, a piece of glass
tubing bent to a right angle being, if necessary, adapted to the
test-tube by means of a cork, and some of the distilled liquid ecol-
lected and examined; finally, the usual group-reagents for the
several metallic and acid radicals are consecutively applied,
Proceeding in this way, the student who has already had some
experience in pharmacy, will not be likely to overlook such solvents
as water, acids, alkalies, aleohol, glycerin, ether, chloroform, ben-
zene, fixed oils, and essential oils, or to miss the substances which
these menstrua may hold in solution, He will probably also recog-
nize such liquids as carbolic acid, formic acid, lactie acid, methyl
alcohol, aldehyde, aniline, nitrobenzene. He must not, however,
suppose that he will always be able to qualitatively analyze, say,
a bottle of medicine so as to ascertain, with certainty, the substance
from which it has been compounded ; for the various infusions,
decoctions, tinctures, wines, syrups, liniments, RR pesices ex-
tracts, pill-masses, and powders contain vegetable
of which are at present almost beyond the reach of f the
Neither the highest skill in analysis nor the largest amount of
experience concerning the odor, appearance, taste, and uses
drugs is sufficient for the certain detection of all these Besse
matters. Skill and experience combined, however, will do much :
and in most cases even so difficult a task as the one just mentioned
may be accomplished with reasonable success. Obviously, quali-
tative analysis alone will not enable the operator to produce a
mixture of substances similar to that analyzed ; to this onal Gena
must be had to quantitative analysis, a subject treated subee-
quently,
Natural fluids, as “ Milk’? and ‘*Urine,’’ admit of special
analytical trentment (see pp. 545 and 574).
>
(as-analysie ix a branch of chemical analysis, chiefly ofa quar
tative character, concerning which information must ft sought 4
CHEMICAL TOXICOLOGY. - 659
other treatises, The analysis of atmospheric air from various
localities, coal-gas, and the gases produced in many technical
operations or obtained in chemical researches, involves appliances
and methods which are scarcely within the sphere of chemistry as
applied to pharmacy or medicine. Beyond the recognition, there-
fore, of oxygen, hydrogen, nitrogen, chlorine, carbonic anhydride,
sulphurous anhydride, nitrous gases, hydrogen sulphide, etc., the
experimental consideration of the chemistry of gaseous substances
may be omitted. Their study, however, should not be neglected,
as existing theoretical conceptions regarding chemical substances
are largely dependent on the observed physical behavior and
chemical relationships of gaseous compounds (see pp. 26 to 37; 46
to 48; 51 to 60).
Spectrum Analysis.—It may be well to state here that the prelim-
inary and final examinations of minute quantities of solid matter
may, in certain cases, profitably include their exposure to a temper-
ature at which they emit light, the flame being physically analyzed
by means of a spectroscope. The spectroscope consists essentially
of a prism to decompose a ray of light into its constituent colors,
with tubes and lenses to collect and transmit the ray or rays to the
eye of the observer. The material to be examined is placed on
the end of a platinum wire, which is then brought within the edge
of the flame of a spirit-lamp or Bunsen burner; yolatilization,
attended usually in the case of a compound by decomposition, at
once occurs, and in presence of certain substances the flame is
tinged with a characteristic hue. When examined by means of
the spectroscope the various colored flames are found to be due in
each case to rays of certain definite degrees of refrangibility, the
latter being indicated by the arrangement of colored ‘* lines”’ (i.¢.,
images of the slit) present in the spectrum of the substance under
examination. Sodium compounds, when examined in this way,
give yellow light only, indicated by a double band of light ina
position corresponding to a portion of the yellow part of an ordi-
nary solar spectrum. The potassium spectrum is mainly composed
of a red and violet band ; lithium gives a crimson, and, ut very
high temperatures, a blue band, and so forth.
By passing white light through a colored substance an ‘‘ absorp-
tion spectrum ’’ will be. produced which is often characteristic, as
in the case of blood or chlorophyll, solution of potassium perman-
gunate, etc.
CHEMICAL TOXICOLOGY.
In cases of criminal and accidental poisoning, the substances
presented to the chemical analyst for examination are usually
560 CHEMICAL TOXICOLOGY.
articles of food, medicines, or vomited matters ; or the liver, kid-
neys, intestines, stomach and contents, removed in course of post-
mortem examination. In these cases some special operations are
necessary before the poison can be isolated in a state of sufficient
purity for the application of the usual tests; for in most instances
the large quantity of animal and vegetable, or, in one word, organic
matter present, prevents or masks the characteristic reactions on
which the tests are founded. These operations will now be de
scribed! ; they form the chemical part of the subject of Toxicology
(rngiKdv, toxicon, poison, and Adéyoc, fogos, discourse).
Substances occurring apparently as definite salts or unmixed
with organic matter need no special treatment, They are analyzed
by the ordinary methods already given, attention being restricted
W poisonous compounds.
EXAMINATION OF AN ORGANIC MIXTURE SUSPECTED TO CON-
TAIN :—MERCURY, ARSENIC, ANTIMONY, LEAD, COPPER,
CHROMIUM, OR ZINC ; SULPHURIC, NITRIC, HYDRO-
CHLORIC, OXALIC, OR HYDROCYANIC ACID; CAUSTIC
ALKALIES ; PHOSPHORUS ; STRYCHNINE, MORPHINE, OR
OTHER POISONOUS ALKALOIDS,
Preliminary Examination.
Odor, Appearance, ete.—Smell the mixture, with the yiew
of ascertaining the presence or absence of any notable quantity
of free hydrocyanic acid. Look carefully for any small solid
particles, such as white arsenic, corrosive sublimate, or verdi-
gris, and for any appearance which may be regarded as
abnormal, any character unusual to the coffee, tea, heer, medi-
cine, vomit, coats of stomach, kidney, liver, or other organ,
tissue, or solid matter under examination.
Poisonous Quantity of Acid.—Add to a small portion some
solution of sodium carbonate, with the view of ascertaining hy
strong effery escence the presence of any large poisonous
quantity of sulphuric, nitric, or hydrochloric acid (p. 563),
Poisonous eayerk 4 of Alkali.—If' so excessively alkaline
as to require the addition of a very large quantity of acid he-
fore, neutralization is e ffected, a noxious quantity of a corrosive
' Materials for these experiments are readily obtained for educational
Pr ases by dissolving the poison in infusions of tea or coffee, in porter
or in water to w hic h some starch mucilage or linseed meal, er peste | be
potato, and fat have been added.
PRELIMINARY EXAMINATION. 561
or caustic alkali is present. Whether soda or potash, etc., is
present is ascertained by the usual tests.
Special Instructions may induce the operator to suspect the
presence of one particular poison. Direct examination for the
latter may then be made, either at once, if the substance has
an aqueous character, or when filtration or treatment with
warm hydrochloric or acetic acid has afforded a more or less
colorless liquid.
Fluids,—A yomit or the contents of a stomach, if set aside
in a long narrow vessel (test-glass or ale-glass), or, hetter,
exposed on a filter during a night, will often yield a more or
less limpid portion at the bottom or top of the solid
matter. This fluid (separated by a pipette or otherwise) will
sometimes respond to tests without further preparation, and
always requires less preparatory treatment than a semi-solid
mixture. If none passes through a filter, a portion often
collects as a lacuna in the upper part,
General Procedure.—If the preliminary examination
does not indicate the method to be pursued, proceed as follows,
treating a portion (not more than one-fourth) of the mixture
for the poisonous metals, another for the acids, and a third
for alkaloids, reserving the remainder for any special experi-
ments which may suggest themselves.
Examination for Mercury, Arsenie, Antimony, Lead,
Copper, Chromium, Zine.
Ifa liquid, acidulate with hydrochloric acid and boil for a
short time. If solid or semi-solid, cut up the matter into smal]
pieces, add enough water to form a fluid mixture, stir in 10 to
20 percent. of pure concentrated hydrochloric acid, and boil
until, from partial aggregation and solution of the solid mat-
ter, filtration can be effected.
Heat a portion of the clear liquid with a thin piece of
bright pure copper or copper gauze, about an inch long and
a quarter of an inch broad, for about ten to twenty minutes ;
metallic mereury, arsenic, or antimony will be deposited on
the copper, darkening it considerably in color. - Pour off the
liquid from the copper, carefully rinse the latter with a little
cold water, dry the piece of metal by holding it over or near
a flame (using fingers, not tongs, or it may become sufficiently
hot for loss of mercury or arsenic to occur by volatilization ),
introduce it into a narrow test-tube or piece of glass tubing
o6
562 CHEMICAL TOXICOLOGY.
closed at one end, and heat the bottom of the tube in a flame,
holding it horizontally so that the upper part of the tube
may be kept cool, and partially closing its mouth with the
finger to prevent escape of vapor. Under these circumstances
any mereury will volatilize from the copper and con-
dense on the cool part of the tube in a ring or patch of
white sublimate, readily aggregating into visible globules on
being pressed by the side of a thin glass rod inserted into
the tube; arsenie will volatize from the copper, and, uniting
with oxygen from the air in the tube, will condense on the
cool part of the glass in a ring or patch of white sublimate of
arsenic (gray and even darker if much metallic arsenic as
well as white arsenic be present), not running into globules
when rubbed, but occurring in small crystals, the character-
istic octahedral form of which (see p. 178) is readily seen by
aid of a good hand-lens or the low power of a microscope ;
antimony volatilizes from the copper if strongly heated, and,
uniting with oxygen, immediately condenses as a slight white
deposit of antimonious oxide close to the copper. (See p. 191.)
Confirmatory Tests. —1. Nothing short of the production of
globules should be wccepted as evidence of the presence of
mercury. It will usually have existed as corrosive sublimate,
2, To confirm indications of the presence of arsenic, a portion of
the acid liquid may be subjected to the hydrogen tests (pp. 179-182);
or the tube containing the white crystalline arsenic may be
broken, and the part on which the sublimate oceurs boiled for some
time in water, and the hydrogen sulphide, ammonio-silver
nitrate, and ammonio-copper sulphate tests (p. 184) applied to
the aqueous solution, 3. For antimony, a portion of the acid
liquid must always be introduced into the hydrogen-apparatus
with the usual precautions. (See p. 191.) 4. Any sulphur
present may darken the copper, and such stained copper may
subseque ntly yield a whitish sublimate of sulphur on the sides
of the subliming tube; such appearances, therefore, are ¢con-
sistent with the entire absence of mercury, arsenic, and antimony.
Note. —Before finally concluding that arsenic is absent from a
fluid, the latter should be warmed with a little sulphurous acid, and
the ordinary “tests then again applied; for arsenic acid and other
arsenates are’ not re mau ily affected by the usual reagents for
Arse nic,
For lead and copper, pass hydrogen sulphide thy h the
clear acidulated liquid for some time, warming the liqu if no
precipitate is produced, or diluting and partially neutralizing
MINERAL, OXALIC, AND HYDROCYANIC ACIDS, 563
the acid by addition of ammonia if much acid has been added.
Collect on a filter any black precipitate that may have
formed; wash, dissolve in a few drops of aqua regia, dilute,
and apply tests, such as ammonia for copper, sulphuric acid
for lead, or any other of the ordinary reagents (pp. 207, 226).
Copper may often be at once detected in «a small quantity of acid-
ulated liquid by immersing the point of a penknife or a piece of
bright iron wire—a deposit of copper, in its characteristic color,
quickly or slowing appearing, according to the amount present
7
(p. 20
Chromium and Zine.—To the acid liquid through which
hydrogen sulphide has been passed, add excess of ammonia
(or to the original acid liquid add excess of ammonia, and then
ammonium hydrosulphide); a precipitate is produced which
may contain alumina, phosphates, chromium, and zinc. (It
is usually blackish, from the presence of ferrous sulphide. )
Collect the precipitate on a filter, wash, dissolve in a little
hydrochloric acid, add a few drops of nitric acid, boil, pour in
excess of ammonia, filter, and test the filtrate with ammonium
hydrosulphide ; a white precipitate indicates zinc. A green
precipitate would indicate chromium. Chromates should also
be sought for (p. 169),
Examination for Mineral Acids, and for Oxalie and Hydro-
cyanic Acids,
To detect hydrochloric, nitric, or sulphuric acid in a liquid
containing organic matter, dilute with water and apply to
smal] portions the usual tests for each acid, disregarding
indications of small quantities, (See pp. 255, 274, 293.)
Excessive acidity, copious evolution of carbonic anhydride on
the addition of sodium carbonate, and very strongly marked reac-
tions on the application of the usual reagents to small portions of
the fluid presented for analysis, collectively form sufficient evidence
of the occurrence of a poisonous amount of either of the three
common mineral acids, but in important cases quantitative analyses ,
should be made. Small quantities of the hydrochloric, nitric,
and sulphuric radicals, oceurring as metallic salts or acids, are
common normal constituents of food; hence the direction to disre-
gard insignificant indications. If the fluid under examination be
a vomit or the contents of a stomach, and an antidote has been
administered, free acid may not be found, but, instead, a large
amount of the corresponding salt.
ob4 CHEMICAL TOXICOLOGY.
For oxalic acid, filter or strain a portion of the liquid, if
not already clear, and add solution of lead acetate so long as
a precipitate is produced ; collect the precipitate, which in any
case is only partly lead oxalate, on a filter, wash, transfer it to
a test-tube or test-glass, add a little water, and pass hydrogen
sulphide through the mixture for a short time; any lead oxalate
is thus converted into insoluble lead sulphide, while oxalic
acid is set free in the solution. Filter, boil to get rid of
hydrogen sulphide, and to the clear filtrate apply the usual
teats for oxalic acid (see p. 303),
The contents of a stomach containing oxalic acid will often be
of «a dark-brown color with a tinge of green (altered blood and
mucus), and the viscid mixture generally, though slowly, affords
some clear, limpid, almost colorless, liquid by filtration or on
standing.
For hydroeyanic acid, the three chief tests may be applied
at once to the liquid or semi-liquid organic mixture, whether
it has an odor of hydrocyanie acid or not. First :—Half fill
a small porcelain crucible with the material, add eight or ten
drops of concentrated sulphuric acid, stir gently with a glass
rod, and invert over the mouth of the crucible a watch-glass
moistened with a small drop of solution of silver nitrate; a
white film on the silver solution is probably silver cyanide,
formed by the action of the gaseous hydrocyanic acid on the
silver nitrate. Second :—Prepare a small quantity of the
organic mixture as before, slightly moistening the centre of the
watch-glass with solution of potassium hydroxide ; here, again,
the heat generated by the action of the concentrated acid is
sufficient to volatilize some of the hydrocyanic acid, which, inter-
acting with the potassium hydroxide, forms potassium cyanide,
On removing thewatch-glass and stirring into it suecessivel)
solution of a ferrous salt, a ferric salt, and hydrochloric sak
flocks of Prussian blue are produced if hydroeyanie acid is
present. Third:—Proceed as before, moistening the watch-
glass with yellow ammonium hydrosulphide; after exposure
_ to the hydrocyanic acid gas for five to ten minutes, add a drop
of ammonia water, evaporate to dryness at a low tempern-
ture, then add a drop of hydrochloric acid and of solution of
ferric chloride ; a blood-red color, due to ferric thiocyanate, is
produced if cyanogen is present,
If the above reactions are not well marked, the organic mixture
may be carefully and slowly distilled in a small retort, the neck
STRYCHNINE AND MORPHINE. 565
of which passes into a bottle and dips beneath the surface of a
little water at the bottom of the bottle; the reagents may then be
applied to separate portions of the distillate,
The examination of organic mixtures for hydrocyanic acid must
be made without delay, as the poison soon begins to decompose,
and in a day or two may be destroyed.
Examination for Phosphorus.
A paste containing phosphorus is commonly employed for
destroying vermin. In cases of poisoning, the phosphorus is
generally in sufficient quantity to be recognized by its charac-
teristic unpleasant smell. A stomach in which it occurs not
infrequently exhibits slight luminosity if opened in a dark
room. When the phosphorus is too small in quantity or too
much diffused to afford this appearance, a portion of the
material is placed in a flask, water acidulated with sulphuric
acid added, a long wide glass tube fitted to the neck of the
flask by a cork, and the mixture gently boiled. If phosphorus
is present (even 1 part in 2,000,000, according to De Vrij)
the top of the column of steam as it condenses in the tube
will appear distinctly phosphorescent when viewed in a dark
room. From its liability to oxidation, phosphorus cannot be
detected after much exposure of an organic mixture to air,
Examination for Strychnine and Morphine.
Strychnine.—If solid or semi-solid, digest the matter with
water and about 10 percent. of hydrochloric acid till liquid,
filter, evaporate to dryness on a water-bath. If the organic
mixture is already liquid, it is simply acidulated with hydro-
chloric acid and evaporated to dryness, The acid residue
is next treated with alcohol as long as anything is dis-
solved, the filtered tincture evaporated to dryness over the
water-bath, and the residue digested in water and filtered.
This slightly acid aqueous solution must now be rendered
alkaline by addition of ammonia, and well shaken in a
closed bottle or long tube with about half an ounce of chloro-
form, and set aside until the chloroform has subsided. The
chloroform (which contains the strychnine) is then removed
by means of a pipette, the presence of any aqueous liquid
being carefully avoided, and evaporated to dryness in a small
basin over a water-bath, the residue moistened with concen-
trated sulphuric acid, and the basin kept over the water-bath
566 CHEMICAL TOXICOLOGY.
for several hours. (It is highly important that the sulphuric
acid used in this operation should be free from nitrous com-
pounds, Test the acid, therefore, by adding powdered ferrous
sulphate, which becomes pink ifnitrous compounds are present.
If these are found, the acid should be purified by strongly
heating with ammonium sulphate, 70 or 80 grains to a pint.)
The charred material is exhausted with water, filtered, excess
of ammonia added, the filtrate shaken with about a quarter
of an ounce of chloroform, the mixture set aside for the chloro-
form to separate, and the chloroform again removed, If on
evaporating a small portion of this chloroform solution to dry-
ness, adding a drop of sulphuric acid to the residue, and warm-
ing, any darkening of color or charring takes place, the strych-
nine is not sufficiently pure for chemical detection; in that
case the rest of the chloroform must be removed by evapora-
tion, and the residue redigested in warm sulphuric acid for
two or three hours. Dilution, neutralization of acid by addi-
tion of ammonia, and agitation with chloroform is again prac-
tised, and the residue of a small portion of the chloroform
solution once more tested with sulphuric acid, If eharring
still occurs, the treatment must be repeated a third time.
Finally, a part of the chloroform solution is taken up by a
pipette and drop after drop evaporated on one spot of a porce-
nin erucible-lid until a fairly distinct dry residue is obtained,
A drop of sulphuric acid is placed on the spot, another drop
placed near, a minute fragment of potassium dichromate placed
in the second drop, and when the acid has become tinged with
the chromate, one drop drawn across the other ; the character-
istic evanescent purple color is then seen, if strychnine is
present. Other tests (see p. 524) may be applied to similar
spots.
This is Girdwood and Roger’s method for the detection of strych-
nine when mixed withorganic matter. It is tedious but trust-
worthy, i and, though apparently complicated, very simple in
principle », thus—stryc hnine is soluble in acidulated water or aleo-
hol, or in ¢ chloroform, readily removed from an alkaline liquid 1
agitation with chloroform, and not charred or otherwise attack
when heate d to 212° F. (100° C.) with sulphuric acid ; much of
the organic m: atter of ‘the food i is insoluble in water; of that soluble
in water, muc +h is insoluble in alcohol; and of that soluble in
both | me nstrua, all is charred and destroyed by warm sulphuric —
ac id ina shorter or longer time. (See also Stas’s 8 gencral process,
Pp. 568, )
*
MORPHINE AND MECONIC ACID. 567
Morphine and the Meconice Acid with which it is associated
in Opium.—To the liquid or the semi-liquid mixture, warmed
for some time with a small quantity of acetic acid, filtered,
and concentrated if necessary, add solution of lead acetate until
no further precipitate is produced. Filter and examine the
precipitate for meconic acid, reserving the filtrate for the
detection of morphine.
The Precipitate—Wash the precipitate (lead meconate,
ete.) with water, place it in a test-tube or test-glass with a
small quantity of water, pass hydrogen sulphide through the
mixture for a short time, filter, slightly warm in asmall basin,
well stirring to promote removal of excess of the gas, and add
a drop of neutral solution of ferric chloride ; a red color, due
to the formation of ferric meconate, is produced if meconic acid
is present. This color is not destroyed on boiling the liquid
after the addition of one drop of dilute hydrochloric acid, as
is the ease with ferric acetate, nor is it bleached by solution of
corrosive sublimate, thus distinguishing it from ferric thio-
cyanate. It is discharged by hydrochloric acid.
The Filtrate—The solution from which meconic acid has
been removed by adding lead acetate is evaporated to a small
bull over a water-bath, excess of potassium carbonate added,
and evaporation continued to dryness. The residue is then
treated with alcohol, which dissolves the morphine. The
alcoholic solution similarly evaporated may leave the mor-
phine sufficiently pure for the application of the usual tests
(see p. 514) to small portions of the residue. IPf no reaction
is obtained, add a drop of sulphuric acid and a little water to
the residue, and shake with ether, in which the morphine
salt is insoluble. The treatment with ether may be repeated
until nothing more is removed, the acid aqueous liquid
saturated with potassium carbonate, the mixture evaporated
to dryness, the residue digested in alcohol, filtered, and por-
tions of the alcoholic liquid evaporated to obtain spots of mor-
phine for the application of the ordinary tests. —
If much organic matter is believed to remain in the filtrate
after the lead acetate treatment, or if a considerable excess
of lead acetate has been employed, the filtered liquid should
he subjected to a current of hydrogen sulphide until no more
lead sulphide is precipitated; the mixture should then be
filtered, and the filtrate, with the washings from the lead
sulphide, evaporated to a small bulk, excess of potassium
carbonate added, the whole well mixed and agitated with
568 CHEMICAL TOXICOLOGY.
twice or thrice its bulk of a mixture of ether and acetic ether
(ether alone would not dissolve the morphine). On standing,
the ethereal liquid rises to the surface : itis carefully removed,
evaporated to dryness, and the residue tested or further puri-
fied in the mauner described in the preceding
The examination for morphine must be conducted with great
care, and with as large a quantity of material as can be spared;
for its isolation from other organic matter is an operation of diffi-
culty, especially when only a minute proportion of alkaloid is
present. Fortunately the detection of meconic acid does not
involve similar difficulties; and as its reactions are quite charne-
teristic, its presence is held to be strong evidence of the existence
of opium in an organic mixture.
Examination for other Poisonous Alkaloida.,
Stas's Process.—Minutely subdivide any solid matter; to
this and the liquid portion of the vomit, ete., add about
twice their weight of alcohol containing sufficient tartaric
acid distinctly to acidify the mixture. Digest the whole
in a flask at a temperature of 150° to 160° F, (65.5° to
71° C.); set aside to cool; filter. The solution, “which will
contain the whole of the alkaloid, should then be pide 2
nearly to dryness in vacuo, or at all events at a tem
not exceeding 100° F. (37.7° C.), lest volatile ctkaloids
should be dissipated. The residue is next exhausted with cold
absolute alcohol ; filtered ; and the filtrate evaporated to dr
reas with the precautions already stated. The extract is ie
solved in a very smal] quantity of water, treated with excess
of powdered sodium or potassium bicarbonate, and well shaken
with five or six times its volume of pure ether (with
a little acetic ether). This ethereal liquid contains the alka-
loid. Small portions should be evaporated in watch-glasses
and tasted, or tested physically and chemically, according as
the knowledge of collateral circumstances by the operator, or
his e experience, 0 or such reactions as are recorded on pp, 526,
541 may "suggest.
Ifa volatile alkaloid | ‘conine, nicotine, lobeline, sparteine ),
is indicated, the ethe re al el lution, which may contain animal
matter, is removed, agitated | with aqueous solution of 4
sium hy droxide, dec ‘anted, and shaken with dilute sulphurie
acid. ‘On standing, the aqueous portion, containing the alka-
Joid as acid sulphate, subsides ; the upper ethereal |
containing the animal matter is rejected; the acid aqueous
POISONOUS ALKALOIDS, 569
liquid is made alkaline with potassium hydroxide; ether is
added, and the whole well shaken; the ethereal liquid is
decanted, evaporated to dryness in vacuo, or at a low tempera-
ture, and (to get rid of all traces of ammonia) again moistened
with ether and dried, The residue is now tested for the sus-
pected alkaloid by taste, smell, and the application of appro-
priate reagents (pp. 526-541).
If a non-volatile alkaloid (aconitine, atropine, brucine, col-
chicine, emetine, hyoscyamine, physostigmine, solanine, vera-
trine, as well as morphine, codeine, and strychnine, ete. ), is
indicated, further purify by decanting the ethereal liquid from
the lower aqueous solution of sodium bicarbonate, removing
the ether by evaporation, digesting the residue in alcohol,
filtering, evaporating the alcohol, treating the residue with
dilute sulphuric acid, setting aside for a few hours, filtering,
concentrating, adding powdered potassium carbonate, and
finally anhydrous alcohol. The alcoholic liquid, on evapora-
tion, yields the alkaloid in a fit condition for testing in the
manner already stated,
Sonnenschein's Process,—Digest with dilute hydrochloric
acid, evaporate to the consistence of syrup, dilute, set aside for
some hours, filter, Add solution of phosphomolybdie acid so
long as any precipitate is produced, or cloudiness appears ;
collect the precipitate on a small filter; wash it with water
containing phosphomolybdic and nitric acids, and, while still
moist, place it in a flask. Decompose this compound of phos-
phomolybdie acid and alkaloid by adding barium hydroxide
until the stirred mixture is distinctly alkaline, Distil off vola-
tile alkaloids, condensing and collecting these by helpof a
long tube so bent that the apparatus shall act as a retort, the
end of the tube being attached to a bulb or a series of bulbs
containing dilute hydrochloric acid. The acid liquid yields
on evaporation a residue of hydrochlorides of alkaloids. The
latter will afford characteristic reactions with the tests for the
suspected alkaloid, and, on being moistened with barium
hydroxide and warmed, will afford fumes of volatile alkoloids
the odor of which is usually characteristic. The residue in the
flask will contain non-volatile alkaloids. It is treated with
carbonic anhydride to neutralize and precipitate the excess of
baryta as insoluble barium carbonate; the mixture is evapo-
rated to dryness over a water-bath ; and the residue digested
in alcohol. The alcoholic solution evaporated generally yields
the alkaloids in a fit state of testing.
570 CHEMICAL TOXICOLOGY.
Reagents for Alkaloids,
Phosphomolybdic acid forms with ammonium salts, in nitric
acid solution, a remarkably insoluble compound; and it behaves
in a similar manner with salts of those compounds which are
more or less analogous to ammonia—the nitrogenous organic
bases—consequently forming an excellent reagent for their detec-
tion, It may be prepared in the following manner: A solution
of ammonium molybdate is mixed with sodium phosphate, whereby
a precipitate of ammonium phosphomolybdate is produced; the
yellow precipitate, having been washed, is diffused through water,
und heated with sufficient sodium carbonate to dissolve it. The
solution is then evaporated to dryness, and calcined to drive off
the ammonia. In case any of the molybdic compound be reduced
by this operation, the residue must be moistened with nitric acid,
and again calcined. The dry mass is then dissolved in cold water,
the solution strongly acidulated with nitric acid, and water added
until ten parts of the solution contain one of the dry salt. The
liquid, which is of a golden-yellow color, must be preserved from
contact with ammoniacal fumes, It precipitates all the alkaloids
(with the exception of urea) when a mere trace only 1s present.
The precipitates are yellow, generally flocculent, insoluble in
water, alcohol, ether, and dilute mineral acids, with the exception
of phosphoric acid. Nitric, acetic, and oxalic acids, concentrated
and boiling, dissolve them. These compounds are decom
by the alkalies, certain metallic oxides, and the alkali-metal salts,
which separate the alkaloid. To give an idea of the sensitiveness
of this reagent, it may be stated that 0.000071 gramme of strych-
nine gives an appreciable precipitate with one cubic centimetre
of the solution of phosphomolybdic acid,
Phosphoantimonic and phosphotungstic acids are also pr
tants of alkaloids. Platinum, iridium, palladium, and gold o-
rides are occasionally serviceable. Tannic and picric acids, too,
may be used, and a solution of iodine and potassium iodide,
Other special reagents for alkaloids are ‘“Mayer’s'’; “Nessler’s’”
(see p. 616); the double potassium and cadmium iodide; and a
solution of the double potassium and bismuth iodide, The latver
is made (by Thresh) by mixing together one ounce of solution of
bismuth an | ammonium citrate (800 grains in one pint), 90 grains of
potassium iodide, and 90 grains of concentrated hydrochlorie acid.
This orange-colored solution gives a red precipitate with dilute
cold solutions containing alkaloids, |
Ptomaines (rripa, a corpse) have already been alluded to as
including poisonous alkaloids producible from putrefying animal
matters, even the human body itself, during the ordinary processes
of decay, They are distinguished, according to Brouardel and
Boutmy, by a drop or two of a solution of their sulphate convert-
ing « drop of solution of potassium ferricyanide into ferrocyanide,
POISONOUS ALKALOIDS. 571
the mixture then giving a dark-blue precipitate with a ferric salt.
Some other substances also, as morphine, possess this converting
yower.
Tyrotoxvicon,—This plomaine (p. 511) may be isolated and tested
as follows: Prepare an aqueous extract of the cheese, or filter the
cougulated milk, etc. No heat should be applied, and undue
exposure to air should be avoided by using stoppered bottles,
Make the filtered fluid faintly alkaline with sodium carbonate,
and well shake with half its bulk of ether. Allow the perfectly
clear separated ethereal solution to evaporate spontaneously; and,
if necessary, again extract the resulting aqueous residue with water,
shaking with ether, evaporating as before, and testing the residue
in two or three ways. A little placed on the tongue and swal-
lowed will cause more or less of nausea, vomiting, purging, and
headache. Again, the residue is either characteristically crystal-
line, or will become so after standing in a vacuum over sulphuric
acid. Mix two or three drops of sulphuric acid and carbolic acid
on a white plate, and add a few drops of the aqueous residue just
mentioned; if an orange-red or purple color results, the presence
of tyrotoxicon may be suspected, but any nitrate or nitrite present
may cause a similar color, To some of the aqueous residue add
an equal volume of a saturated solution of potassium hydroxide;
the double potassium and diazobenzene hydroxide is then formed
and appears in six-sided plates, whereas any potassium nitrate
appears in prisms. This residue muy be treated with absolute
aleohol, filtered, and the filtrate evaporated, when the plates may
again be observed or the color reaction again obtained with this
purified product (Vaughan),
ANTIDOTES.—See “ Antidotes” in the Index.
—
QUESTIONS AND EXERCISES.
In examining food and similar matter for poison, why must not the
ordinary tests for the poison be at ence applied 9—What preliminary
operations should be performed on a vomit in acase of suapectod poisen-
ing t—How would you search for corrosive sublimate in wine ?—By what
series of operations wonld you satisfy yourself of the presence or absence
of arsenic in the contents of the stomach ?—Describe the treatment to
which decoction of coffee should be subjected in testing it for tartar-emetiec,
State how the oecurrence of lead in water is demonatrated.—Give a pro-
cess for the detection of copper in jam.—How would you detect zine in a
Vomit ?—Tfow may the presence of mach salphuric acid in gin be proved ?
—In testing ale for nitrie acid what reactions would you select ?—Show
how you would conclude that a dangerous quantity of hydroehlorle acid
had been added to cider.— Describe the manipulations necessary in test-
572 MORBID URINE.
ing for hydrocyanic acid in the contents of a stomach —By what method
is oxalic acid discovered in infusion of coffee ?—How phosphorus
detected in organic mixtures ?—Give the process by which strychnine is
isolated from a vomit.—Mention the experiments by which the presence
of luudanum in porter is demonstrated,—Name the antidotes in cases of
poisoning by :—a, alkaloids; 4, antimonials; c, arsenic; d, barium salts
¢, copper compounds: f, hydrochloric acid; g, hydrocyanic acid ; h,
sults; i, corrosive sublimate ; j, nitric acid; k, oxalic acid; /, silver salts ;
m, oil of vitriol ; », tin liquors; o, zinc salts; p, carbolic acid.
EXAMINATION OF URINE AND CALCULL
The various products of the natural and continuous decay of
animal] tissue and the refuse matter of food are eliminated from
the system chiefly as feces, urine, and expired air, Air exhaled
from the lungs carries off from the blood much carbon (about 8
ozs. in 24 hours) in the form of carbonic anhydride, and some
aqueous vapor—the latter, together with a small amount of oily
matter, also escaping by the skin. Directing the breath to a cold
surface renders moisture evident; and breathing through a tube
into lime-water demonstrates the presence of a considerable
quantity of carbonic anhydride. The freces consist mainly of
insoluble débris of the food, mucus from the intestines, and resi-
dues from the biliary and other intestinal secretions, the soluble
matters and water forming the urine, These excretions vary con-
siderably, according to the food and general habits of the indi-
vidual and the external temperature. But in disease the variations
become excessive; hence their detection by the medical practi-
tioner, or by the pharmacist for the medical man, is a matter of
importance,
An analysis of feces or air cannot be made with sufficient ease
and rapidity to be practically available in medical diagnosis, But
with regard to urine, certain abnormal substances and abnormal
quantities of normal constituents may be chemically detected in
the course of a few minutes by any one having already some
knowledge of chemical and microscopical manipulation,
The total amount of urine voided daily under normal conditions
varies considerably, the chief factors in causing variation bei
the amount of fluid taken into the body, and the temperature of
the surroundin gs which causes inverse changes in the quantities
of water removed by the skin, and in the expired air ie aver-
age daily output may be placed at two to three pints in the adult
(1000 to 1500 Ce.),
The amount and character of the solid constituents of urine yar
with the character and quantity of the diet, and the amount
muscular work and corresponding tissue changes. The fr
amount of total solids is usually given at 70 grammes per diem,
of which 40 grammes consist of organic matter and 80 grammes
MORBID URINE. 573
of inorganic salts. The composition of the solids may be stated
in round numbers, in grammes, as follows :—urea 33, creatinine
0.9, urie acid 0.4, hippuric acid 0.4, pigment and other organic
substances 10, chlorine 7.5, sulphuric acid (SO,) 2, phosphoric acid
(P,O,) 8, sodium 11, potassium 2.5, calcium, magnesium, and
ammonium 1,2,
The urea which is present to a considerable extent in urine, is
the form in which the most of the waste nitrogen is eliminated
from the system. Its empirical form is CON,H,. Its structural
formula may be written, coc Re; that is, it may be regarded us
F
carbamide or as one of the organic bases already referred to, a
primary diamine, in which the bivalent radical CO occupies the
place of H,. The other atoms of hydrogen may be displaced by
various radicals, and many compound wreas thus be obtained.
Artificial Urea.—Urea may be prepared artificially by William’s
modification of Wéhler’s method, Potassium cyanide, of the best
commercial quality (containing about 90 percent, of real cyanide),
is fused at a very low red heat in a shallow iron vessel; red lead
is added in small quantities at a time, the temperature being kept
down by constant stirring. When the red lead no longer produces
action, the mixture (potassium cyanate and lead) is allowed to
cool, the product finely powdered, exhausted with cold water,
barium nitrate added till no more precipitate (barium carbonate)
is formed, the mixture filtered, and the filtrate treated with lead
nitrate so long as lead cyanate is precipitated. The latter is
thoroughly washed, and dried at a low temperature. Equivalent
quantities of lead cyanate and ammonium sulphate digested in a
smal! quantity of water at a gentle heat (see p. $24) and filtered,
yield a solution from which urea crystallizes on cooling.
Another process, —Basaroff has found that urea is produced when
ordinary ammonium carbonate is heated in strong hermetically
sealed tubes to about 275° F, (135° C.) fora few hours, The same
chemist had previously obtained urea by similarly heating pure
ammonium carbamate ; so that the source of the urea in the former
case is probably the ammonium carbamate believed to occur in the
carbonate (see p. 96),
NH,NH,CO, — H,O = CO(NH,),
Tests for Urea,—1. Crystals of uren, cautiously heated in a test-
tube, give an odor of ammonia, and a substance called biwre? is
formed, which, when dissolved in water, gives a rose-red color on
adding a trace of cupric sulphate and excess of potassium hydrox-
ide,
2. Concentrated solutions of urea, such as are obtained by evapo-
rating normal urine to one-fourth of its bulk, give with an equal
volume of concentrated nitric acid an abundant crop of crystals
74 ; MORBID URINE,
of urea nitrate, in octahedral and hexagonal prisms. Oxalic acid
under similar conditions yields flat-rhombobedral prisms.
3. Nitrous acid or hypobromites give a brisk effervescence of
nitrogen,
4, Caustic alkalies cause an evolution of ammonia. _A similar
production of ammonia is caused by several micro-organisms, not-
ably micrococcus uree which is the cause of the decomposition of
urea, with evolution of ammonia, observed in stale urine. A
enzyme has been isolated from this organism which also decom-
poses urea with evolution of ammonia,
PuHysicAL EXAMINATION OF URINE.
Normal urine varies in color from a light straw yellow to dark
brown, the average being a golden yellow. The pigment present
in largest quantity and to which the normal color of urine is almost
wholly due is wrochrome. The other pigments present are, urobi-
lin, uroerythrin, and hematoporphyrin, The presence of blood
causes a variation in color from a slight smoky brown to a deep
red according to the amount of blood, Bile gives the urine a
greenish-brown color. Both color and odor are much influenced
by certain kinds of food and by some drugs. Thus santonin and
chrysophanic acid color the urine orange. To distinguish these
add sodium hydroxide, which gives a red color ; shake with amyl
alcohol, when the color if due to santonin dissolves in the aleohol
and then, in contact with air, changes to yellow ; the color due to
chrysophanic acid does not dissolve in the amyl alcohol or only in
traces (Hoppe-Seyler). The odor of diabetic urine not infrequently
is that of acetone, from the presence of that substance. Many
drugs, for example, cubebs, and some foods, as asparagus, give
special odors to urine, .
Fresh urine is clear, Any turbidity may be due to urates,
phosphates, fat-globules, or pus. Urates redissolve when the
urine is warmed ; phosphates on addition of acetic acid ; pus and
fat are detected by the microscope, vide infra. If the urine be
turbid from the presence of phosphates when first voided, it ma
be due to conversion of urea into ammonium carbonate, whi
precipitates the phosphates within the bladder, in which case the
fresh and warm urine will effervesce slightly on the addition of
acetic acid. This condition is abnormal,
On standing, healthy urine commonly gives a slight cloud of
mucus, and after severe exercise may give a sediment of Urates.
The specific rravity of urine should be taken on a specimen
removed from the whole bulk excreted in twenty or twenty-four
hours ; the normal specific gravity varies between 1,016 to 1.026.
Many qualitative experiments and all quantitative opertions
should only be performed on the mixed urine of twenty-four
hours,
ALBUMIN. 575
Healthy urine when fresh is always slightly acid, the acidity
being due to the presence of acid sodium phosphate. Alkalinity
is probably due to that conversion of urea into ammonium car-
bonate within the bladder already described,
EXAMINATION OF MORBID URINE FOR ALBUMIN, SUGAR,
BILE, BLOOD, EXCESS OF UREA, DEFICIENCY OF CHLO-
RIDES, ETC. ; AND URINARY SEDIMENT FOR URATES (OR
LITHATES ), PHOSPHATES, CALCIUM OXALATE, AND URIC
ACID,
Albumin.—Faintly acidulate a portion of the clear urine
in a test-tube with a few drops of dilute acetic acid (to keep
phosphates in solution), and boil; flocks or coagula will sepa-
rute if albumin be present. To detect small quantities, nearly
fill a long test-tube with clear urine filtered if necessary, and
faintly acidulated with acetic acid ; then, holding the tube by
its lower end, boil the upper portion of the urine.—A cloudi-
ness in the boiled portion (as compared with the unboiled
portion), which, on further addition of a few drops of acetic
acid, does not disappear, indicates the presence of albumin.—
Or, place a little nitric acid in a test-tube; then carefully
pour down the side of the tube a little of the urine, so that it
may lie above the acid. Ifalbumin he present, an amorphous
whitish ring or coagulum will, sooner or later, be formed at
the junction of the fluids (Heller's test).
These experiments should first be made on normal urine con-
taining a. drop or two of solution of whiteof egg, The coagulum
is white if it is only albumin, greenish if bile-pigment be present,
and brownish-red if the urine contain blood. The influence of
acids and alkalies on the precipitation of albumin is .noticed on
page 5435,
A saturated solution of picric acid at once precipitates any albu-
min from urine. Should the urine be alkaline, it must be acidu-
lated before applying this test. On warming the mixture, the
precipitate will become more pronounced if due to the albumin or
globulin of blood, or to any modifications of albumin caused by
acidity or alkalinity of urine; but will disappear if due to peptone
or prepeptone, Potassium ferrocyanide, also, will precipitate the
former varieties of albumin, but not the peptones,
Other forms of Proteid,—Halliburton suggests the following
sequence of operations for the detection of the various forms of
proteid which may occasionally be present in abnormal urine. 1, If
576 MOBBID URINE.
the urine gives no precipitate on boiling after acidulation, albu-
min and globulin are absent. If a precipitate occurs, albumin or
globulin or both are present, 2. If the urine after neutralization
gives no precipitate on saturation with magnesium sulphate, globu-
lin and hetero-proteose are absent. If such a precipitate occurs,
one or other is present. 3, If the urine be saturated with ammo-
nium sulphate, filtered, and the filtrate gives no xanthropoteic or
biuret reaction—a rose-red color with cupric sulphate and a large
excess of potassium hydroxide—peptone is absent. 4, If the urine
gives no precipitation on boiling after acidulation, no precipitate
with nitric acid, and no precipitate on adding ammonium sulphate
to saturation, peptone can be the only proteid present, Confirm
this by the biuret reaction.
The occurrence of albumin in the urine may be temporary and
of but little importance; or it may indicate the existence of a
serious affection, known as Bright's disease. ‘* Albuminaria is
rurely a serious condition unless it is sufficiently pronounced to be
made out by the cold nitric acid test.’’ (Steward,)
For quantitative purposes, Esbach employs the picric test, dis-
solving LO parts of picric acid and 20 of citric acide in 900 of water,
by aid of heat, and when the solution is cold, diluting with water
to 1000 parts. This solution is added to a given volume of urine
in a graduated Cetti’s Esbach tube, and the height of the precipi-
tate is noted after 24 hours. Johnson finds a simple solution of
5 grains of picric acid in 1 fluid ounce of water better than Esbach’s
solution, because the excess of acid in the latter tends to precipi-
tate much uric acid which would be reckoned as albumin. If
necessary, a standard value is given to the solution in the first
instance by washing, drying and weighing the albumin.
A peculiar form of albuminaria called ‘‘ Bence Jones Albumo-
suria’’ has now been described in a considerable number of cases,
It is connected with a uniformly fatal multiple ulceration and
softening of bone, and the proteid present is intermediate between
albumin and the albumoses, being coagulable at a low temperature
(60° C.) and redissolving to a great extent on boiling. It is also
different from ordinary albumin in being readily soluble on boiling
with hydrochloric acid.
Sugar. —To « portion of the clear liquid in a test-tube add
fiv @ to ten 1 drops of solution of cupric sulphate; pour in solu-
jum hydroxide until the precipitate first formed
is a aeakied slowly heat the solution to near the boiling-
point 5 ay vellow, yellowish-red, or red precipitate (cuprous
oxide) is formed if sugar be present, (The production of
rose-red or pink tint with the cold alkaline cupric solution
indicates the presence of albumoses or peptones. )
BILE. 577
This experiment should first be made on urine containing a drop
or two of grape-sugar (p,482). The cupric hydroxide precipitated
by the alkali is insoluble in excess of pure potassium hydroxide,
but readily dissolves if organic matter, especially sugar, be present,
The cupric salt should not contain iron,
Other tests may be applied if necessary (see pp, 482 and 485).
See also the Quantitative Determination of Sugar on p. 676. — In
any case in which, while the copper test points to sugar, medical
diagnosis does not point to diabetes, the copper test should be
checked by a fermentation test, for after the administration of
chloral, camphor, morphine, phenol, and many other drugs, there
may temporarily occur in the urine a compound termed glyeuronic
acid, which with the copper test affords a reaction identical with
that of sugar,
Sugar is present in minute traces only in normal urine. In
searching for small quantities, uric acid and creatinine, which
also reduce the copper-solution, should first be removed by precipi-
tution with solution of mercuric chloride (in the presence of sodium
acetate, which promotes the precipitation), and removal of excess
of mercury from the clear liquid by addition of ammonia. Normal
urine rotates the plane of polarization of light slightly to the left,
but if even a small amount of sugar be present, dextro-rotation
results, In larger quantities (often 5 percent.) sugar is a churac-
teristic constituent of the urine of diabetic patients, greatly in-
creasing the specific gravity of the secretion, Small hydrometers
(termed wrinometera) are commonly employed for ascertaining the
specific gravity of urine,
Bile. —This is detected by the dark greenish-brown color of the
urine and by the general tests described on p. 550. In doubtful
cases the urine should be thoroughly shaken up with a little chloro-
form, which dissolves the bile-pignfents, and Gmelin’s test applied
to the separated chloroform. Oliver recommends that the urine
be diluted to a sp. gr. of 1.008 and then one volume be added to
three volumes of the following reagent, when more or less opales-
cence will be produced, according to the amount of bile acids
present. For the reagent, dissolve 30 grains of flesh peptone, 4
grains of salicylic acid, and 80 minims of official acetic acid, in 8
ounces of water ; filter,
Blood..—The presence of blood in the urine may be detected by
the color if the amount be not too small, by the spectroscope, or
by the guaiacum test, which consists in the production of a blue
color when ozonic ether (made by adding hydrogen peroxide to
ether) and tincture of guaiacum are added to the urine. This test
is delicate, but is given by other substances, and ought to be con-
firmed by other tests,
Excess of Uris Acid.—A rough quantitative process con-
sists in applying the qualitative method already described
oF
578 MORBID URINE.
(p. 345) to a known volume of urine, and collecting on a
filter, washing and weighing the resulting uric acid. The
result is always low, Hopkins saturates the urine with
ammonium chloride, and, after a couple hours, decom:
the separated ammonium urate by means of hydrochloric acid,
and collects, washes, dries, and weighs the resulting uric acid.
The normal yield should be roughly 0.3 to 0,5 per 1000, See
Proceedings of the Royal Society, vol. lii, p. 93.
Exeess of Urea,—About one-third of the solid matter in
the urine is urea, Its proportion varies considerably ; but 2
percent. may be regarded as an average quantity, With
regard to the amount of urea in urine, it is impossible to
sharply define excess or deficiency. If nitric acid, added in
equal volume, gives crystals without concentration, excess is
certainly present in the sample examined: though, if the
amount of urine passed in the twenty-four hours is much
below the average, the total quantity of urea excreted may
not be abnormal.
For quantitative determinations, the urine is treated in a
suitable apparatus with an alkaline solution of recently prepared
sodium hypobromite, and the nitrogen thus liberated is collected
and measured. The reaction is of the following character:—
CO(NH,), + 38NaBrO = 3NaBr + CO, + 2H,0+ N,
Urea Sodium Sodinm Carbonic Water Nitrogen
hypobromite bromide anhydride
The carbonic anhydride represented in the equation is absorbed
by the excess of alkali used in making up the hypobromite solu-
tion, so that only the nitrogen is evolved in gaseous form. Only
about 94 percent. of the nitrogen appears in gaseous form,’ and
allowance must be made for this deficiency if an instrument grad-
uated in Ce.’s is employed for the determination. Usually, the ~
instruments used clinically are, however, graduated in percentages,
and in that case allowance is made in the initial graduation of
the instrument.
Many forms of instrument have been devised for determining
the urea from the evolved nitrogen in this reaction, but they all fall
into one of two classes: first, that in which air is present over the
hypobromite, with which the evolve d nitrogen mixes and in which
the amount of nitrogen is estimated from the inerense ip
volume of the gas whic ‘h is driven into a graduated cylinder; and,
secondly, those in which the nitrogen is evolved alone in a grad-
uated tube filled with the hypobromite solution. The principle
‘In diabetic urine nearly the theoretical yield is obtained.
UREA, 579
of the first type of apparatus is shown in Fig. 49 which has been
constructed from ordinary laboratory apparatus. The burette
fixed in the stand has air-tight connec-
tions above with the wide-mouthed bot- Fic. 49.
tle, and below with a funnel by means
of rubber tubing. The burette is filled
with water, which also fills the connect-
ing tube and funnel to an equal level.
The bottle contains 24 Cc, of the hypo-
bromite solution, made by adding 2 Ce.
of bromine to 28 Ce, of 40 percent,
solution of sodium hydroxide, and 5
Cc, of urine in a short wide test-tube
are placed within the bottle, so that
later, by tilting the bottle, the urine and
hypobromite may be mixed, After
placing the cork air-tight in the bottle,
the level of the water in the burette is
read, the water in the funnel being —\
adjusted at an equal level, then the 2 oa
urine and hypobromite are mixed, and —=S
after an interval of ten minutes, the
new level of the water is read. The difference in the readings gives
the volume of nitrogen evolved; and 35.4 Ce. of nitrogen
(measured at 18°C, and 760 mm, pressure) correspond to 0.1
gramme of urea, from which the percentage of urea can easily be
calculated. Care must be taken to keep the temperature constant
throughout the experiment by immersing the bottle in a bath of
water, otherwise a large error will result from the change in
volume of the contained air,
The other type of apparatus (Doremus Ureometer, Fig. 50) is
simpler and sufficiently accurate for all clinical purposes. The
hypobromite solution is made to completely fill a graduated tube
closed at the upper end and bent in ‘‘U"’ form at the bottom,
beyond the bend a bulb is blown to contain the hypobromite
displaced from the tube, and a short length of tubing reaches
above the bulb. The tube is filled and also the bend and lower
part of the bulb, by first filling the bulb with the solution and
then slowly inverting so as to displace the air. On again turning
up the tube the hypobromite completely fills the graduated tube,
bend, and lower part of bulb, One Ce, of urine is now introduced
by means of a bent pipette graduated to deliver 1 Ce, and filled
and emptied by means of a rubber bulb at itsend. Care must be
taken to introduce all the urine and yet not to blow in bubbles
of air, In a recent modification the urine is added from a small
graduated tube attached to the side of the hypobromite tube and
separated from it by a stopcock, These instruments are usually
graduated in percentages of urea to obviate calculations,
580 MORBID URINE.
In these instruments no error is introduced from changes in
volume of admixed air, and although the quantity of urine used
is small, they are fairly accurate.
A still more recent form of instrument for measuring small
amounts of urea in blood or urine is that of Barcroft, in which
the volume of gas and air is reduced to the sume as that at the
beginning, by applying pressure, and differences in pressure are
measured instead of differences in volume,
It may be said of all these instruments that they do not
measure the amount of urea with scientific accuracy, because, in
the first place, all the urea-nitrogen is not given off; and, in the
second, a small amount is set free from uric acid and other nitrog-
enous substances present in the urine, but for clinical purposes they
vive a very close approximation to the amount of urea present.
Chlorides. —Any ordinary sample of urine yields an abundant
precipitate of silver chloride on the addition
Fia. 50, of nitric acid and silver nitrate. The amount
of chlorides present may be determined by any
of the usual methods for the determination of
chlorides. The normal quantity of chlorine
present as chlorides is 0.5 percent.; but this
may be reduced practically to nif in acute feb-
rile conditions, such as pneumonia, partially
from the stoppage of intake of chlorides in the
food, and partially from increased metabolism
of proteid binding the chlorides of the tissues,
and blood, and lymph.
Chromogens.—Urine may contain chromo-
gens. These are substances which do not at
the time color the urine, but which, on the
addition of oxidizing reagents, or after stand-
Doremus ureometer, ing some time, develop a color. A blue color
. may be seen in urine rich in indican on the ad-
dition of much nitric acid. This is due to the formation of indigo
from its chromogen. The darkening often noticed on the addi-
tion of acid to urine is due to liberation of the urinary pigments
from their chromogens.
Acetone in urine occurs usually in the later stages of diabetes
mellitus, ‘Halliburton thus desc ribes a delicate test by Le Nobel,
On adding an: alkaline solution of sodium nitroprusside, so dilute as
to have » only a slight red tint, toa fluid containing acetone, a raby-
red color is pro oduced, which ina few moments changes lo yellow,
i i a
aur 0 ezhs oiling, afte or Ac dding ac cid, to greenish- blue or violet.
5"
lang
—=
= |
_
=_
=
!
=
=
|
I
=
=f
So of Sidoleen: is eiaindll “Alcohol ‘must not be resent, “0
that the iodine must on no account be added as Tinet. Jodi,
UREA,
581
The Color of Urine. Caution. —Care must be taken not to con-
found the color-changes in urine due to the action of drugs with
the effects produced by the action of oxidizing agents on chromo-
gens. Thus rhubarb, saffron, and suntonin darken the natural
yellow of urine, the addition of an alkali causing a red colora-
tion. Carbolic acid taken internally, or absorbed from exten-
sive wounds after surgical operations, makes the urine greenish-
black, resembling urine with much bile in it. If potassium
iodide or bromide is being taken internally, the addition of a
strong acid will often cause separation of iodine or bromine
respectively in the urine, Medicinal astringents tend to reduce
the normal color of urine, Many soluble inorganic and organic
medicinal substances pass out of the system with the urine, some-
times quite unchanged in character. Pepsin has been found in
urine. ‘‘Small pieces of fibrin soaked in the urine absorb the
pepsin therefrom; on removing them to 0.1 percent, hydrochloric
acid they are rapidly digested” (Leo),
Aceto-acetic acid is also found associated with acetone and /j-oxy-
butyric acid in diabetic urine. It may be detected by adding very
dilute solution of ferric chloride cautiously drop by drop to the
suspected urine, The first portion added precipitates the phos-
phates, which if present in excess may be filtered off. The first
trace of ferric chloride after the phosphates have been precipi-
tated gives a burgundy red color, which disappears on heating
the solution, and does not re-appear on cooling. This final stage
of the test ought always to be performed, since it serves to dis-
tinguish the aceto-acetic acid from other substances which may be
present, and give a similar result in the first part of the test, 7. ¢.,
the color reaction with ferric chloride in the cold.
URINARY SEDIMENTS.
Warm the sediment with the supernatant urine, and filter.
Insoluble.
Phosphates, calcium oxalate, and uric acid.
’
Varm with acetic acid, and filter,
Insoluble,
Calcium oxalate and wric acid.
Warm with hydrochloric
acid, filter.
————
Inaoluble.
| Soluble,
Phosphates,
Add ammonia ;
white ppt.—cal-
cium phosphate
Sol uble.
‘Ammonium, cal-
‘cium, or sodium
lurates; chiefly
the latter,
They are re-
deposited as the
liquid cools, and
if sufficient in
quantity may
Soluble, OF AINMON LUI be further ex-
Urie acid. Calcium h oxhbte oe? ned for
Apply the Oxalate, oth, ; be mniiomagc (4 cal-
murexid test | May be repre cium, sodin ad
(p. 346), cipitated by and the uric ack
mabe radical by the ap-
| propriate tests,
O82 MORBID URINE,
Notes.—Urinary deposits are seldom of a complex character:
the action of heat and acetic and hydrochloric acids generally at
once indicates the character of the deposit, rendering filtratjon
and precipitation unnecessary.
The Urates are often of a pink or red color, owing to the pres-
ence of a pigment termed wroerylhrin or purpurin ; hence the
common name of red gravel for such deposits. /urpurin is solu-
ble in aleohol, and may be removed by dissolving the deposit by
heating, and extracting with amyl alcohol. It is seldom mneces-—
sury to determine whether the urate be that of ammonium, ¢al-
cium, or sodium (see also Uric acid, p. 345). The deposited urate
is a very acid urate (quadriurate) which slowly (more grees in
urine diluted with water) breaks up into a Jess acid urate
and uric acid (Bence Jones), the supernatant urine Sebastes x
the same time less acid owing to the formation of mono- ey di-
hydrogen phosphates. The presence in the urine of mono-hydro-
gen phosphates, is apparently (Roberts) what prevents this decom-
position before the urine is exposed to the air.
Calcium phosphate and ammonium magnesium phosphate
(NH ,MgPO,), are usually both present in a phosphatic deposit,
the magnesium salt forming the larger proportion, They may, if
necessary, and if sufficient in quantity, be separated hy collecting
on filter, washing, and boiling with solution of sodium carbon-
ate. The calcium and magnesium carbonates thus formed are col-
lected on a filter, washed, and dissolved in a drop or two of hydro-
chiorie acid; ammonium chloride, ammonia, and ammonium car-
bonate are added, and the mixture boiled and filtered; any calcium
originally present will then remain insoluble, as calcium carbonate;
while any magnesium will be precipitated from the filtrate as
ammonium magnesium phosphate on the addition of sodium phos-
phate, the mixture being also well stirred.—The chief portion
of excreted earthy phosphates is carried off by the féeces, that
remaining in the urine being kept in solution by the influence of
acid sodium phosphate and, frequently, lactic acid. —Oeccasionally,
an hour or two after a hearty meal, the urine becomes su
ciently alkaline for the phosphates to be deposited, and the urine
when passed is turbid from their presence. —The ammoniacal con-
stituent of the ammonium magnesium salt does not oceur normally,
but is produced from urea as soon as urine becomes alkaline,
Calcium oxalate is seldom met with in excessive amounts, but
very often in small quantities mixed with phosphates, In the
urine it is probably kept in solution by the influence of the acid
sodium phosphate. In one case of oxaluria the whole urine
excreted by the patient in twenty-four hours furnished to the
author only two-thirds of a grain of calcium oxalate.
Free uric acid is in most cases distinctly crystalline, and near]
always of a yellow, red, or brown color owing to the presence rel
imi puri ties.
URINARY SEDIMENTS. 583
Artificial Sediments.—For educational practice, these may be
obtained as follows:—l1I. Triturate in a mortar a few grains of ser-
pent’s excrement (chiefly ammonium urate) with an ounce or two
of urine; this represents a sediment of urates, 2, Add a few
drops of ammonia water or solution of ammonium carbonate to
urine; the deposit may be regarded as one of phosphates, 3.
To an ounce or two of urine add very small quantities of cal-
cium chloride and ammonium oxalate ; the precipitate is calcium
oxalate. 4. To urine acidulated with hydrochloric acid add a
little serpent’s excrement; the sediment is uric acid.
Other deposits than the foregoing are occasionally observed. Thus
hippuric acid, HCSH,NO,, a normal constituent of human urine
and largely contained in the urine of herbivorous animals, is
sometimes found associated with uric acid in urinary sediments,
especially in those from patients whose medicine contains benzoic
acid (p. 325), Its appearance, as observed by aid of the micro-
scope, is characteristic—namely, slender, four-sided prisms, hav-
ing pointed ends. Cystin, C,H NSO, (from «iar, fuatis, a blad-
der, in allusion to its origin) rarely occurs as a deposit in urine,
It is not soluble in warm urine or dilute acetic acid, and scarcely
in dilute hydrochloric acid—hence would be met with in testing
for free uric acid, It is very soluble in ammonia, recrystallizing
from a drop of the solution placed on a piece of glass in charac-
teristic microscopic six-sided plates. It communicates an odor, as
of sweet briar, to fresh urine, soon changing to a most unpleasant
smell. Leucine and tyrosine (see p. 510) are occasionally met with
in cases of phosphorus poisoning and of acute yellow atrophy of
the liver. As a rule they occur together in the form of small
round yellowish masses of radiating crystals. Organized sedi-
ments may be due to the corpuscles of pus, mucus, or blood, fat-
globules, spermatozoa, cylindrical casts of the tubes of the kid-
neys, epithelial cells from the walls of the bladder, or foreign
matters, such as fibres of wool, or of cotton or wood, smal! feath-
ers, dust, starch, ete.; these are best recognized by the microscope.
(See the accompanying illustrations, and the following paragraphs
on the microscopic appearances of both crystalline and organized
urinary sediments. )
Microscopic EXAMINATION OF URINARY SEDIMENTS,
Urine containing insoluble matter is usually more or less opaque.
For microscopical examination a few ounces should be set aside
in a conical test-glass for an hour or two, the clear supernatant
urine poured off from the sediment as far as possible, a small
drop of the residue placed on a slip of glass, covered with a
cover-alip, and examined under the microscope with different
magnifying powers,
584 ' MORBID URINE
The respective appearances of the various crystalline and or-
ganized matters are given in Figs. 51 to 62 which were kindly
drawn by the late H. B. Brady, F. R.S., from natural specimens
in the collections of St. Bartholomew's Hospital, Dr. Sedgwick,
the late Mr. W. W, Stoddart, Mr. Waddington, and the Author,
Urie acid occurs in many forms, most of which are given in
Figs. 51 and 52. Flat more or less oval crystals, sometimes
attached to each other, their outline then resembling an 8, a
cross, Or a star, are common, Single and grouped quadratic
prisms, aigrettes, spicula, and crystals recalling dumb-bells are
Tric acid.
met with. From urine acidulated with hydrochloric acid, bun-
dies or sheaves of square crystals, two opposite sides smooth and
two jagged, are generally deposited : acidulated with acetic acid,
more typical forms are obtained, A drop of solution of tas-
sium hydroxide placed on the glass slip w ill dissolve a deposit
of uric acid, a drop of any acid reprecipitating it in minute but
characteristic crystals.
Cystin is very rarely met with as an urinary deposit ; that from
which Fig. 153 was taken was found in the urine of a patient
in St. Bartholomew's Hospital, Lamellw of cystin always
assume the hexagonal character; but the angles are some-
times ill- de fined and the plates superposed : in the latter case,
a drop of ammonia water pl: aced on the glass at once dissolves
the deposit, well-marked six-sided crystals appearing as the drop
dries up,
Triple phosphate (ammonium magnesium phosphate) is deposited
as soon as urine becomes alkaline, the ammoniacal constituent
being furnished by the decomposition of urea, Tt oceurs in
prismatic crystals, forming a beautiful object when viewed
polarized light, sometimes also in ragged stellate or arborescent
URINARY SEDIMENTS. 585
crystals, resembling those of snow. Both forms may be artificially
prepared by adding a small lump of ammonium carbonate to a
few ounces of urine und setting aside in a test-glass. (Fig. 54.)
Amorphous depomts are either earthy phosphates (a mixture of
magnesium snd calcium phosphates) or wrates of calcium, mag-
nexium, ammonium, potassium, or sodium—chiefly the latter,
They may be distinguished by the action of a drop of acetic acid
placed near the sediment on the glass slip, the effect on mixing
being watched under the microscope ; phosphates dissolve, while
Cystin. Triple phosphate,
urates give rise to characteristic forms of uric acid, Urates redis-
solve when warmed with the supernatant urine,
Sodium and magnesium urates, though generally amorphous,
occasionally take a crystalline form—bundles or tufts of small
needles—as shown in Figs. 55 and 56. When pink or brick-red,
the color is due to uroerythrin,
Calcium oxalate commonly occurs in octahedra requiring highly
magnifying-power for their detection, The crystals are ensily over-
looked if other matters are present, but are more distinctly seen
after phosphates have been removed by acetic acid. In certain
aspects the smaller crystals look like square plates traversed by a
crows, A dumb-bell form of this deposit ia also sometimes seen,
resembling certain forms of uric acid and the coalescing spherules
of a much rarer sediment—calcium carbonate, Calcium oxalate
is insoluble in acetic but soluble in hydrochloric acid, The octa-
hedra are frequently met with in the urine of persons who have
partaken of garden rhubarb and certain other vegetables, The
crystals may often be deposited artificially (according to Wadding-
ton) by dropping a fragment of oxalic acid into several ounces of
urine and setting aside for a few hours,
90356 MORBID URINE.
Calcium carbonate is rarely found in the urine of man, but
frequently in that of the horse and other herbivorous animals,
Human urine containing calcium carbonate often reddens litmus-
paper ; and it is only after the removal, on standing, of the excess
of carbonic acid, that the salt is deposited, It consists of minute
spherules, varying in size, the smaller ones often in process of
coalescence. The dumb-bell form thus produced is easily dis-
tinguished from similar groups of uric acid or calcium oxalate by
showing a black cross in each spherule when viewed by polarized
light. Acetic acid dissolves calcium carbonate, liberating car-
bonic anhydride with visible effervescence pres the microscope)
if the slide has been previously warmed and a group of crystals be
}
Calcium carbonate, Hippuric acid.
les
a,ofSodium; >Calcium oxalate,
6b, of Magnesium. }
Hippurie acid.—The pointed rhombic prisms and acicular crys-
tals are characteristic and easily recognized. The broader crystals
may possibly be mistaken for triple phosphate, and the narrower
for certain forms of uric acid ; but insolubility in acetic acid dis-
tinguishes them from the former, and solubility in aleohol from
the latter. These tests may be applied while the deposit is under
microscopic observation, An alcoholic solution of hippurie acid
evaporated to dryness, and the residue treated with water, gives
a solution from which characteristic crystalline forms of hippuric
acid may be obtained on allowing a drop to dry on a slip of glass,
The organized deposits in urine entail greater care in their deter-
mination, and usually require a higher magnifying power for their
proper examination than those of crystalline form. The
are drawn to 230 diameters, The following notes will assist the
observer:
Casts of uriniferous tubuli are of various forms, and often of con-
sitlerable Jength—sometimes delicate and transparent, occasionally
URINARY SEDIMENTS. 587
granular, and often beset with fat-globules. Epithelial débris are
frequently present in urine in the form of nucleated cells, regular
and oval when full, but angular and unsymmetrical when parti-
ally emptied of their contents—sometimes perfect, but more
frequently broken up. Casts are very readily discovered by the
use of the microscope, if, to a sample of the urine supposed to con-
tain them, best in a conical glass, a few drops. of an aniline dye be
added,’ ‘*Carbofuchsine’’ answers well, The casts rapidly stain,
and are then quite easily seen in the field. (Fig. 57).
Blood corpuscles are readily identified under the microscope by
their characteristic appearance ; they are usually crenated when
present; if the hemoglobin has escaped, the stroma is often
Epithelial cells and tubull. Blood-corpuscles,
visible for some time, forming what is termed a shadow, The tests
for blood, or rather hemoglobin in solution, have already been
described (ace p. 577). It is noteworthy that when the blood is
present in small quantities the spectrum obtained is that of
methemoglobin and not that of oxvhemoglobin. When corpus-
cles are present, the condition is known as hematuria; when the
blood coloring-matter is in solution, as hemoglobinuria,
Tt is not possible to state with certainty whether the blood cor-
puscles found in urine are those of man, or of the domestic mam-
malia, for the slight differences in size are not sufficiently charac-
teristic or fixed.
Pus and mucus.—Purulent urine deposits, on standing, a light-
yellow layer, easily diffused through the liquid by shaking. Acetic
acid does not dissolve the sediment; and solution of potassium
hydroxide of official etrength converte it into a gelatinona mass, Under
the microscope, pus-corpuscles appear rounded and colorless,
rather larger than blood-disks, and somewhat granular on the sur-
588 MORBID URINE.
face. The corpuscles may be made more distinct by staining
with a dilute solution of methylene blue. They generally show
minute nuclei, which are more distinctly seen after treatment with
acetic acid. (See the portion of Fig. 59 marked a.). Mucus pos-
Fic. 59.
Pus-corpuscles, Fat-globules.
sesses no definite microscopic characters, but commonly has tm-
bedded in it pus, epithelium, and air-bubbles. Mucus is coagu-
Jated in a characteristic manner by acetic acid ; and this reaction,
together with the ropy appearance it imparts to urine, prevents it
being confounded with pus.
Fra, 61. Fig, 62.
Spermatozoa, Sarcina ventricull,
Fatty matter (lipuiria) occurs either as minute, highly refractile,
glittering globules partially diffused through the urine (as shown
|
— Se
URINARY CALCULL 589
at a) or in more intimate emulsion (as at ) in Fig. 60), When
present in larger quantity, it collects as a sort of skim on the sur-
face after standing.
Spermatozoa are liable to escape notice, on account of their small
size and extreme transparency. Suspected urine should be allowed
to settle some hours in a conical test-glass, and the drop at the
bottom examined under a high power. Fig. 61 shows their
appearance, ‘They become more apparent after staining by an ani-
lin dye such as methylene blue,
Sarcine rarely occur in urine, but are not infrequent in vomited
matters, The upper figures (Fig. 62, ‘} are copied from Dr.
Thudichum's drawing (from urine); the larger groupings (b) are
from vomited matter.
Extraneous bodies, such as starch, hair, wool, fibres of cotton or
of deal, or fragments of feathers, are often found in urinary
deposits ; and ludicrous mistakes have been made by observers not
on their guard in respect to such casual admixtures,
EXAMINATION OF URINARY CALCULL
The term ca/eu/us is the diminutive of ealx, a lime- or chalk-stone,
The following calculi have been met with :—(1) Uric acid, (2)
Sodium urate, (3) Calcium oxalate (mulberry), (4) Fusible or
mixed calcium and triple phosphates, (5) Calcium phosphate, (6)
Calcium carbonate, (7) Xanthine, (8) Cystin, (9) Urostealith (fatty
matter), (10) Indigo (one ease).
Knowledge of the composition of a calculus or urinary deposit
affords valuable diagnostic aid to the physician ; hence the import-
ance of a trustworthy analysis of these substances,
Nature of Cateuli,—Urinary calculi have the same composition
as unorganized urinary sediments. They consist, in short, of sedi-
ments that have been deposited slowly within the bladder, particle
on particle, layer on layer, the several substances becoming so com-
pact as to be less easily acted on by reagents than when deposited
after the urine has been passed—the urates Jess readily soluble in
warm water, the calcium phosphate insoluble in acetic acid until
aha been dissolved in hydrochloric acid and reprecipitated by an
alkali,
Preliminary Treatment, —If the calculus is whole, saw it in two
through the centre, and notice whether it is built up of distinct
layers or apparently consists of one substance. If the latter, use
about « grain of the sawdust for analysis ; if the former, carefully
scrape off portions of each layer, and examine them separately. If
the caleulus is in fragments, select fair specimens of about half a
grain or a grain each, and reduce to a fine powder by placing on
a hard surface and crushing under the blade of a knife.
Analysis.—Commence the analysis by heating a portion,
about the size of a pin’s head, on platinum foil, in order to
=
590 MORBID URINE.
ascertain whether organic matter, inorganic matter, or both
are present. If both, the ash is examined for inorganic
. substances, and a fresh portion of the calculus for urie acid
by the murexid test. (In the absence of uric acid any slight
charring may be considered to be due to indefinite organic
matter.) If composed of organic matter only, the caleulus
will in nearly all cases be uric acid, the indication being con-
firmed by applying the murexid test in a watch-glass to an-
other fragment, half the size of a small pin’s head. If in-
organic only, the ash on the platinum foil may be examined
for phosphates, and a separate portion of the calculus for
oxalates, Even a single drop of liquid obtained in any of
these experiments may be filtered by placing it on a filter not
exceeding 20 mm. in diameter and previously moistened with
water, and adding three or four drops of water, one after the
other as each passes through the paper ; or a drop of the mix-
ture may be placed on a fragment of damped filter-paper
on a glass slide, the latter then tilted, and a clear drop be
drained off from the paper on to the slide ready for the addi-
tion of a reagent, If the calculus is suspected to contain
more than one substance, boil about a grain of the powder in
half a test-tubeful of distilled water for a few minutes and
pour it on a small filter; then proceed according to the follow-
ing Table :—
Insoluble. . Soluble.
Phosphates, calcium oxalate, and free uric acid, Urates.
Boil with two or three drops of hydrochloric These will prob
acid, and filter. ably be epos-
ited as the solution
cools, Small quanti-
Inaolwble, Soluble. | ties may be detected
7.) | by evaporating the
Urie acid, | Phosphates and calcium oxalate. solution to dryness.
Apply the | Add excess of ammonia, and then They are tested for
murexid | excess of neetic acid ; filter, ammonium, so-
Lest | | dium, calcium, and
(p. 346). the urie acid radi-
Insoluble, Soluble. | cal by the appropri-
| | ole reagents
Calcium | Phosphates,
oxalate, = | They may be |
_re-pptd. by ammonia. |
|
URINARY CALCULL 591
Varieties of Caleuli,—Calculi composed entirely of urie acid are
common; a minute portion heated on platinum foil chars, burns,
and leaves scarcely a trace of ash. The phosphates frequently
occur together, forming what is known as the fusib/e caleu/us, from
the readiness with which u fragment aggregates, and even fuses to
a bead, when heated on a loop of platinum wire in the blowyipe-
flame. The phosphates may, if necessary, be examined further
by the method described in connection with urinary deposits.
Calcium oxalate often occurs alone, forming a dark-colored calculus
having a very rough surface, hence termed the mudberry calculus.
Smaller calculi of the same substance are called, from their appear-
ance, hempseed caleuli. Calculi of eystin are rarely met with.
Xanthine (from favtlde «canthos, yellow, in allusion to the color it
yields with nitric acid) still less often occurs as a calculus. The
earthy concretions or ‘* cha/k-stones,’’ which frequently form in
the joints of gouty persons, are composed chiefly of biurates, the
sodium salt being that most commonly met with, Gadll/-stones or
biliary caleuli, occasionally form in the gall-bladder ; they consist
chiefly of cholesterin (from ors, cholé, biles, and orepedc, stereos,
solid), C,,H,.OH, which is chemically an alcohol, but in its solu-
bilities resembles the fats; it is soluble in alcohol or ether,
and crystallizes from such solutions in well-defined, square, scaly
crystals which are characterized by possessing a notch at one
corner, Phosphatic and other calculi of many pounds weight
are Ages found in the stomach and larger intestines of
animals,
QUESTIONS AND EXERCISES,
In breathing, how much carbon (in the form of carbonic anhydride) is
exhaled from the lungs every twenty-four hours ?—How may the presenes
of carbonic anhydride in expired air be demonstrated 7—Mention an exper-
iment showing the escape of moisture from the lungs during breathing. —
State the method of testing for albumin in urine.—Give the tests for sugar
in urine.—What is the average composition of healthy urine?—Give the
tests for urea.—Write the rational formule of some compound ureas in
which methyl or ethy! displaces hydrogen.— Describe au artificial process
for the production of urea, giving equations.—Sketch out o plan for the
chemical examination of urinary sediments.—A deposit is insoluble in the
supernatant urine or inaoetic acid; of what substance may it consist ?—
Which compounds are indicated when a deposit redissolves on warming it
with the supernatant urine }—Name the salts insoluble in warmed urine,
but dissolved on the addition of acetic acid.—Mention the chemical char-
acters of cystin.—At what stage of analysis would it be recognized j—
Describe the microscopical appearances of the following urinary deposits :
uric acid, eystin, triple phosphate, calcium phosphate, wrates, calcium
oxalate, calcium carbonate, hippuric acid, tube-ensts, epithelial débris,
blood, pus, muecns, fal, spermatozoa, surcinw, extraneous bodies,—State
the physical and chemical characters of urinary calculi.—How are
ay OFFICIAL GALENICAL PREPARATIONS.
urinary calculi prepared for chemical examination ?—Construct a scheme
for the chemical examination of urinary caleulii—What is the composi-
tion of "fusible calculus,” and why is this calculus so-called ?—State the
characters of * “mulberry ame pe calculi,—W hat are © chalk-
stones " of gout, and “ gall-stones"’ or “ biliary calculi?”
THE GALENICAL PREPARATIONS OF THE
UNITED STATES PHARMACOPCEIA
The preparation of Cerates, Confections, Decoctions,
Extracts, Glycerites, Infusions, Juices, Liniments, Lozenges,
Mixtures, Ointments, Pills, Plasters, Powders, Spirits, Sup-
positories, Syrups, Tinctures, and Winea, includes a number
of mechanical rather than chemical operations, and belongs to
the domain of pure Pharmacy. The medical or pharmaceu-
tieal student will probably have had some opportunity of
practically studying these compounds before working at exper-
imental chemistry, and may have prepared many of them
according to the directions of the Pharmacopoeia ; if not, he is
referred to the pages of the last edition of that work for
details.
THE CHEMICAL PREPARATIONS OF THE
UNITED STATES PHARMACOPCEIA
Processes by which many official chemical substances may
he prepared have now been described, and the strictly chem-
ical character of the processes has been illustrated by experi-
ments aud explained by aid of equations. Should the reader,
in addition, desire an intimate acquaintance with those details
of manipulation on which the successful and economic manu-
fueture of chemical substances depends, he is advised to pre-
pare, if he has not done so already, a few ounces of each of
the salts mentioned in the Pharmacopoia or commonly used
in Pharmacy, A Dic tionary or some of the larger text-hooks
of € ‘hemistry may also be consulted,
The product tion of many chemical and galenical substances
om a commercial scale can only he suecessfully carried on i
manufacturing Inboratories, and with some knowledge of the
circumstances of supply and demand, and of the value of raw
QUANTITATIVE MEASUREMENTS. 595
material, by products, ete.; for the technical preparation of
such substances requires much knowledge beyond eyen a
thorough acquaintance with chemistry, till, in the present
day, commercial Chemistry and Pharmacy can best hope for
success when founded on the working out of abstract scientific
principles. The problem of manufacturing success is now only
solved with certainty by sound and wisely-applied science.
QUANTITATIVE MEASUREMENTS
Temperature
General Principles.—As a general rule, to which, however,
there are some exceptions, substances expand when heated and
vontract when cooled, the alteration in volume being approxi-
mately constant and regular for equal increments or decrements of
temperature, The extent of this alteration in a given substance,
expressed in parts or degrees, constitutes the usual method of
intelligibly stating with accuracy, precision, and minuteness a
particular condition of warmth or temperature—that is, of sensible
heat. The substance commonly employed for this purpose is
mercury, the chief advantages of which are, that it will bear a
moderately high temperature without boiling, a low. temperature
without freezing, does not adhere to glass to a sufficient extent to
‘‘wet’’ the sides of any tube in which it may be enclosed, and,
from its good conducting-power for heat, responds rapidly to
changes of temperature, Platinum earthenware, alcohol, and
air are also occasionally used for thermometric purposes.
The Thermometer,—The construction of an accurate ther-
mometer is a matter of considerable difficulty ; but the follow-
ing are the leading steps in the operation. Select a piece of
glass tubing having a fine capillary (eapi//us, a hair) bore,
and about a foot long; heat one extremity in a blowpipe-
flame until the orifice closes, and the glass is sufficiently soft
to admit of a bulb being blown; heat the bulb to expel air,
immediately plunging the open extremity of the tube into
mercury ; the bulb haying cooled, and some mercury haying
entered and taken the place of expelled air, again heat the bulb
and the tube until the mercury boils and its vapor escapes
through the bore of the tube ; again plunge the extremity under
mercury, which will probably now completely fill the bulb
and tube. When cold, the bulb is placed in melting ice,
38
594 QUANTITATIVE MEASUREMENTS.
The top of the column of mercury in the capillary tube
should then be within an inch or two of the bulb; if higher,
some of the mercury must be expelled by heat ; if lower, more
metal must be introduced as before. The tube is now heated
near the open end anda portion drawn out, until the diameter
is reduced to about one-tenth. The bulb is next warmed
until the mercurial column rises above the constricted part of
the tube, which is then rapidly fused in the blowpipe-flame,
and the extremity of the tube removed.
The instrument is now ready for graduation. The bulb is
placed in the steam just above some rapidly boiling water
(a medium haying, ceteris paribus, an invariable tempera-
ture), and when the position of the top of the mercurial
column is constant (the flask containing the water and steam
being jacketed to prevent loss of heat by radiation), a tem-
porary mark is made on the stem to indicate this position.
This operation is repeated with melting ice (also a medium
having an invariable temperature). The space between these
two marks is divided into a certain number of intervals
termed degrees. Unfortunately, this number is not uniform
in all countries: in Britain it is 180, as proposed by Fahren-
heit; in France 100 (the Centigrade scale) as proposed hy
Celsius, a number generally adopted by scientific men; in
some parts of Europe the divisions are 80 for-the same
interval, as suggested by Réaumer. Whichever be the
number selected, similar markings should be continued beyond
the boiling and freezing points as far as the length of the stem
admits. They may be etched permanently on the stem itself,
or on any wood, metal, or earthenware frame on which the
stem is mounted,
In ascertaining the temperature of a liquid, the bulb of a
thermometer is simply inserted and the degree noted. In
determining the boiling-point, also, the bulb may be inserted
in the liquid, if a pure substance. In taking the boiling-point
of a substance which is being distilled from a mixture, the
bulb of the thermometer should be in the vapor but not
beneath nor very near to the surface of the boiling liquid.
The “ boiling-point” of a liquid is the temperature at which
the pressure of the vapor of the substance overcomes the
atmospheric or other pressure to which the liquid is exposed.
When the pressure is equal to 760 mm. (29.92 inches) of
mereury, Water boils at 100° C. (212° F.). The boilin
point of a drop of a fluid is taken by introducing it into the
TEMPERATURE, 595
closed extremity of a small U tube, the remaining portion of
the closed limb being filled with mercury, The tube is low-
ered into a bath, the open limb being above the surface of
the fluid of the bath. The bath is slowly and equally heated,
and the boiling-point of the liquid, indicated by the mercury
falling until it is level m the two limbs, taken by a thermom-
eter whose bulb is close to the U tube,
Determination of Boiling-Point.—*‘To determine the boil-
ing-point of a substance, the liquid under examination should
be placed in a distilling flask having a side tube for conyvey-
ing the vapor to a condenser, while the thermometer
through a cork inserted in the neck. ‘The bulb of the ther-
mometer should be near to, but not immersed in, the liquid,
and the whole of the thread of mercury should, if possible, be
surrounded by the vapor; the temperature is read off as soon
as the liquid is distilling freely. If any considerable length of
the mercurial column be not surrounded by the vapor, the
temperature of the emergent column should be ascertained as
directed under melting-points [see next page], and the neces-
sary correction applied.”—B., P., 1898.
The following are the boiling-points of a few substances met
with in pharmacy :—
Centigrade, | Fahrenheit.
Alcohol, absolute
“ annyl
Bromine ......-. |
Chloroform eo 140 to 141.8
Ether (Cabont) . . Ce TO ae OG
Mercury i vacuo (as in a thermometer) . | 580
sll in air (barom. at 30 inches) . . 57.5 675.05
Phenol (not hyherthan) ...... . : STOA
Water (barom, at 29.92 inches) . . . . 212
ia ( ui 99,33 ub . 21]
ba ( ir’ 28.74 dé
Saturated solutions of :—
Cream of tartar... . see
Common galt... .-.-s-
Salammoning ....... .%
Sodium nitrate
acetate
Calcium chloride
596 QUANTITATIVE MEASUREMENTS.
Determination of Melting-Point.—To melt at a given tem-
perature is a constant property of a substance; therefore a
melting-point, once it is accurately determined, becomes a valu-
able indicator of purity in a substance. The description given
in the British Pharmacopeeia of 1898 of the modeof making a
melting-point determination is as follows :—**To determine the
melting-point of a substance a minute fragment of it should
be placed in a thin-walled glass tube having an internal diam-
eter of about 1 millimetre (, inch), and sealed at the lower
end, This tube should be attached to the thermometer so
that the substance is near the middle of the bulb, and the
thermometer with the attached tube should be immersed in a
suitable liquid, contained in a beaker placed over a small lamp
flame. Water is suitable for substances melting below 212
F. (100° C.), sulphuric acid, hard paraffin, or glycerin for
substances melting at higher temperatures. The liquid should
be continually stirred by means of a glass ring moved up and
down until the substance is seen to melt. The temperature is
noted, the tube cooled until the substance solidifies, and the
operation then repeated. The latter reading of the thermom-
eter should be taken as the melting-point. To obtain accu-
rate results, the whole of the mercury column of the thermom-
eter should be immersed in the heated liquid, but as this is
seldom practicable, the mean temperature of the emergent
column—that is, of that portion above the surface of the
heated liquid—should be ascertained and the necessary correc-
tion applied. To obtain the mean temperature of the emer-
gent column, a smal] thermometer is fixed by India-rubber
bands in such a position that its bulb is about the middle of
the emergent column. The corrected temperature may be
calculated with approximate accuracy from the formula :—
Corrected Temperature—T +-.000143 (T — t)N,
in which
T—observed, i.¢., uncorrected, temperature ;
t—mean temperature of the emergent column ;
N=the length of the emergent column in scale degrees.”
TEMPERATURE. 597
The following are melting-pointa of substances official in the
Pharmacopoeia :—
In degrees In degrees
Centigrade, Fahrenbeit.
Benzoie acid
Oiloftheobroma . .
Phosphorus
Prepared lard
- suet
Spermaceti rar ; ) to
fhite wax .,. : | ‘anh to 149
Yellow wax . , < ‘ P } 143.6 to 147.8
~ Pyrometers,—Temperatures above the hoilfag-point of mer-
cury are determined by ascertaining to what extent a bar of
platinum or porcelain has elongated, The bar is enclosed in
a cavity of a suitable ease, a plug of platinum or porcelain
placed at one end of the bar, and the whole exposed in the
region the temperature of which is to be found. After cool-
ing, the distance to which the bar has forced the plug along
the cavity is accurately measured and the corresponding
degree of temperature noted. The value of the distance is
fixed for low temperatures by comparison with a mercurial
thermometer, and the scale carried upward through intervals
of equivalent length. Such thermometers are conventionally
distinguished from ordinary instruments by the name pyrom-
eter (from zip, pur, fire and pétpeov, metron, measure ),
T he order of fusibility of a few of the metals is as follows :—
In degrees In degrees
Centigrade. Fahrenheit.
. — $0.4 — SY
Potaminel }. 62.5 + 144.4
Sodium :% 97.6 207.7
Tin siphd so 297.8 442
Bismuth : 264 HOT
»| $85 617
411.6 779
pe We : ae RS 621 1150
Silver 1023 1873
Copper .. 3, a 1008 1o08
Goh 1102 2016
Cust iron .. . - ad 1530 2786
598 QUANTITATIVE MEASUREMENTS.
QUESTIONS AND EXERCISES.
On what general principles are thermometers constructed }—What ma-
terial is employed in making thermometers ?—Why is mercury selected
as a thermometric indicator ?— Describe the manufacture of a mercurial
thermometer.—How are thermometers graduated /—State the boiling-
points of aleohol, chloroform, ether, mercury, and wateron either ther-
mometric scale.—Describo the details of manipulation in determining the
melting-points of solids.—In what respect do pyrometers differ from
thermometers ?—Mention the melting-points of glacial acetic acid, oil of
theobroma, lard, suet, and wax.—Give the fusing-points of tin, lead, zine,
copper, and cast iron.
Weight.
The Balanee.—The balance used in the quantitative operations
of chemistry must be accurate and sensitive. The points of sus-
pension of the beam and pan should be polished steel or agate
knife-edges, working on agate planes. It should turn easily
and quickly, without too much oscillation, to s}g or gig Of a
grain, or ,', of a milligramme, when 1000 grains, or 50 or 60
grammes, are placed in each pan, (Grammes are weights of the
metric system, a description of which & given on pages 40-43).
The beam should be light but strong, capable of supporting a
load of 1500 grains or 100 grammes; its oscillations are observed
by help of a long index attached to its centre, and continued
downward for some distance in front of the supporting pillar of
the balance. The instrument should be provided with screws for
purposes of adjustment, a mechanical contrivance for supporting
the beam above its bearings when not in use or during the
removal or addition of weights, spirit-levels to enable the oper-
ator to place the balance in a horizontal position, and the whole
should be enclosed in a glass case to protect it from dust. It
should be placed in a room the atmosphere of which is not liable
to be contaminated by acid fumes, and in a situation as free as
possible from vibration. During weighing, the doors of the
balance-case should be shut, in order that currents of air may
not unequally influence the pans.
The Weights.—These should be preserved in a box haying a
separate compartment for each weight. A weight should not be
lifted direc tly with the fingers, but by the aid of a small pair of
forceps. vt grain- -weights, they should range from LOOO grains
to 7g grain, with a 5, made of gold wire to act as a ‘rider’? on
the divided beam, and thus indic: ate by its position 100ths and
1000ths of a grain. From ,', to 10 grains the we ights may be of
platinum or aluminium ; 3 thence upward to 1000 grains of gilt or
platinized brass. The relation of the weights to each other should
be de cimal, Metric decimal weights may range from 100 grammes
to 1 gramme of gilt or platinized brass, and thence down-
*
SPECIAL GRAVITY. 599
ward to 1 centigramme, of platinum or aluminium, a gold centi-
gramme rider being employed to indicate milligrammes and tenths
of a milligramme,
Specific Gravity or Relative Density.
The specific gravity, or relative density, of a substance is the
ratio of its weights to that of an equal volume of a standard sul-
stance. This comparative heaviness in the case of sofids and
liquids is conventionally expressed in relation to water: they are
considered as being lighter or heavier than water. Thus, water
being regarded as unity =1, the relative density, or specific grav-
ity, of ether is represented by the figures 0.716 (it is less than
three-fourths, 0,750, the weight of water), oil of vitriol by 1,826
(it is nearly twice, 2.000, as heavy as water), The specific gravi-
ties of substances are, morever, the weights of similar volumes af
25° C, (77° F.); for the weight of a definite volume of any sub-
stance varies according to temperature, becoming, as a rule,
heavier when cooled and lighter when heated, different substances
(gases excepted) differing in the extent to which they contract
and expand. While, then, specific gravity is, truly, the com-
parative weight of equal bulks, the numbers which, in the United
States, commonly represent specific gravities are the comparative
weights of equal bulks at 25°C. (77° F.), water being taken as
unity.* The standard of comparison for gases was formerly air,
but is now usually hydrogen.
Sreciric GRAVITY or Liqurps.
Procure any stall bottle holding from 100 to 1000 grains,
and haying a narrow neck; counterpoise it in a delicate bal-
ance ; fill it to about half-way up the neck with pure distilled
water having a temperature of 25° C. (77° F.); ascertain the
weight of the water, and, for convenience, add or subtract a
drop or two, so that the weight shall be a round number of
grains ; mark the veck by the aid of a diamond or file-point
at the level of the lower edge of the curved surface of the
water. Consecutively fill up the bottle to this neckmark with
several other liquids, cooled or warmed to 25°C. (77° F.),
first rinsing out the bottle once or twice with a small quantity
of each liquid, and note the weights; the respective figures
''The true weight of a substance is ite weight in air plus the weight of
an equal yvolome of air and minus the weight of a volume of air equal to
the volume of the brass or other weights employed ; or, in other words,
its weight in vacuo, uninflucnced by the buoyancy of the air; but such a
correction of the weight of a substance is seldom necessary, or, indwed,
desirable,
600 QUANTITATIVE MEASUREMENTS
represent the relative weights of equal volumes of the liquids.
If the capacity of the bottle is 100, or 1000 grains, the result-
ing weights will, without calculation, show the specific grayi-
ties of the liquids; if any other number, a simple calculation
must be worked out to ascertain the weight of the liquids as com-
pared with 1 (or 1.000) of water. Bottles conveniently ad-
Fia, 63. Fie, 64. Fira. 65, Fra, 66.
Specific ¢ gravity bottles.
justed to contain 250, 500, or 1000 grains, or 50 or 100
grammes water, when filled-to the top of their perforated stopper
(Fig. 65), and other forms of the instrument, are sold by all
chemical-apparatus makers. Fig. 66 is that of a bottle
extremely useful in ascertaining the specific gravities of the
volatile liquids,
Verify some of the following stated specific gravities of official
liquids ; —
Acid, acetic
- diluted .
wlacial . .
hydrochloric .
“diluted .
nitric
~ diluted .
phosphori ic, diluted
sulphuric .
* afomatic .
> diluted. .
sulphurous, solution of
Alcohol, absolute (real). .
. =< ( official )
‘ (92.3 percent.) .
ia (41.5 5 id j =
Ammonia, aromatic spirit of
- waler .
water, stronger... « -
ad
Renzole .
( ‘hloroform i '
Creosote .. . oy .« « « » « » DOt below 1072
SPECIAL GRAVITY,
0.716 to 0.717
“ spirit of nitrous 8
Glycerin |
Ferric chloride, solution of
“ sulphate, "
Leal paren, as
Lime, syrup ©
Mercury (at o° C.=
" (at 25° C.
= nitrate, solution of
Oil of eucalyptus
bd
i
Potassium Hydroxide, solution of
Soda, solution of, chlorinated
Syrup
“ of ferrous iodide .
Hydrometers, formerly termed areometers,—The specific gravity
of liquids may be ascertained, without balance and weights, by
means of the hydrometer—an instrument usually of glass, having
a graduated stem and a bulb or bulbs at the lower part. The
specific gravity of a liquid is indicated by the depth to which the
hydrometer sinks in the liquid, the point marked 1.0 or 1000
upon the scale indicating the depth to which it sinks in pure
water, Hydrometers constructed for special purposes are known
under the names of saccharometer, |actometer, elaometer, urinom-
eter, aleoholometer. Hydrometers require a considerable quan-
tity of liquid fairly to float them ; and specific gravities observed
with them are usually less delicate and trustworthy than those
obtained by the balance, nevertheless they are exceedingly use-
ful for many practical purposes where the employment of a deli-
cate balance would be inadmissible,
Sreeciric GRAVITY OF SoLIps InN MaAss.
Weigh in the usual manner a piece (50 to 250 grains) of
any solid substance heavier than water. Then weigh it in
water, by suspending it from a shortened balance-pan by a
fine hair or filament of silk and immersing in a vessel of water
(Fig. 67). The buoyant properties of the water will cause the
solid apparently to lose weight; this loss in weight is the
exact weight of a volume of water equal to the volume of the
immersed object. The weight of the substance and the weight
of an equal volume of water being thus ascertained, a simple
calculation gives the relative weight of the substance, as com-
pared with water—=1.000. Divide the weight in air by the
602 QUANTITATIVE MEASUREMENTS.
loss of weight in water, the resulting number is the specific
gravity in relation to 1 part of water, the conventional stand-
ard of comparison.
Fie. 67.
Weighing a solid in water.
Verify some of the following specific gravities :—
DL a in eee . 256
Antimony . PE F eta ere We
Bismuth .. on oe a eu S ie
Coins, Kk nglish, “gold . re 2.40 ee)
mVOEr, «5° # © a. 4 wim bbe ee
Y ad ee eer ee
Copper. . otha sh atten een See 2 ae
Gade ym ee BS . 19.34
Oe ad eh aes Pes SG UNO a toh ba ca, op fo
LAUS ovat. os 16 SEA ld, ofa. os Wa cus te it et On
Magnesium. ... . Shae Biel tls on oe
mane) ws GD. ae lata bated a . 270
PRORIOTUS . 6 6 ku tee ane ib wd ud 0 hee
Prt ew tc eh mw hl On we Se
ee A ee
Cl SB
Ee ey ee) en ae fy
Specific gravities o f solid substances should be taken in water
having a temperature of 25° (C. 77° F.). The substance should
be immersed about half an ine h below the surface of the water :
adhe ‘ring air- bubb les mtist be e ure fully re moved ; the substance
must be quite insoluble in water,
SPECIFIC GRAVITY. 603
Sreciric GRAVITY OF SOLIDS IN PowDER OR SMALL
FRAGMENTS.
Weigh the particles ; place them in a counterpoised specific-
gravity bottle of known capacity, and fill up with water,
taking care that the substance is thoroughly wetted ; again
weigh. From the combined weights of water and substance
subtract the amount due to the substance: the residue is the
weight of the water. Subtract this weight of water from the
quantity which the bottle normally contains: the residue is
the amount of water displaced by the substance. Having thus
obtained the weights of equal volumes of water and substance,
the specific gravity of the latter, as compared with water =
1.000, is obtained by dividing the weight of the substance by
the weight of the water.
Or, suspend a cup, short glass tube, or bucket from a
shortened balance-pan ; immerse in water; counterpoise ; place
the weighed powder in the cup, and proceed aa directed for
taking the specific gravity of a solid in mass.
This operation may be conducted on fragments of any of the
substances the specific gravities of which are given in the foregoing
Table, or on the powdered piece of marble the specific gravity of
which has been taken in mass, The specific gravity of one piece
of glass, first in mass, then in powder, may be ascertained ; the
results should be identical, The specific gravity of shot is about
11.350; sand 2,600; mereury, 13.535,
Speciric GRAVITY OF SOLIDS SOLUBLE IN WATER.
Weigh a piece of sugar or other substance soluble in water ;
then suspend it from a balance in the usual manner, and
weigh it in turpentine, benzol, or petroleum, the specific
gravity of which is known or has been previously determined;
the loss in weight is the weight of an equal volume of the
turpentine, i.e, it is the weight of the turpentine displaced hy
the substance. Ascertain the weight of an equal yolume of
water by calculation ;—
Sp. gr. of . sp. gr. of .. weight of turpen- . weight of an equal
turpentine *" water ‘* tine displaced * volume of water.
The exact weights of equal volumes of sugar and water having
heen obtained, the specific gravity of sugar, as compared with
water = 1,000 is obtained by calculation. Divide the weight
of the sugar by that of the equal volume of water, the quotient
604 QUANTITATIVE MEASUREMENTS.
is the specific gravity of sugar. The specific gravity of sugar
ranges from 1,590 to 1.607.
Sprciric GRAVITY orf So_ips LIGHTER THAN WATER.
This is obtained in a manner similar to that for solids
heavier than water ; but the light substance is sunk by attach-
ing it to a piece of heavy metal, the weight of water which the
latter displaces being deducted from the weight displaced by
both ; the remainder is the weight of a quantity of water equal
in volume to the light substance. For instance, a piece of wood
weighing 12 grammes (or grains—for it is assumed that the stu-
dent works equally well with metric as with imperial weights)
is tied to a pieceof metal weighing 22 grammes, the loss of
weight of the metal in water previously having been found to
be 3 grammes. The two, weighing 34 grammes, are now im-
mersed, and the loss in weight is found to be 26 grammes.
But of this loss 3 grammes have been proved to he due to the
buoyant action of the water on the metal; the ene 23,
therefore, represent the same effect on the wood ; 23 and 12,
therefore, represent the weights of equal volumes of water and
of the wood, and 23: 12::1:0.5217. Or, shortly, as before,
divide the weight of the wood in air by the weight of an equal
volume of water; 0.5217 is the specific gravity of the wood.
Another specimen of wood may be found to be three-fourths
(0.750) the weight of water, and others heavier. Cork varies
from 0.100 to 0.300,
The specific gravity of a very minute quantity of a heavy or
light substance may be ascertained by noting the specific gravity
of a fluid in which it, being insoluble, neither sinks nor swims ;
or by immersing it in a weighed piece of paraflin whose specific
gravity is known, noting the specific gravity of the whole, and
correcting for the influence of the paraffin.
SPEeciric GRAVITY OF GASES.
The determination is analogous to that in the case of liquids.
A globe exhausted of air and hol: ling from 1 to 4 litres (or Quarts)
is suspended from the arm of a balance, and counterpoised by a
similar flask. Gases are introduced in succession and their weights
noted, By calculation their specific gravities ure obtained in
relation to air or hydrogen, whichever is taken as a standard.
Correction of the Volume of « 7asea for Preasure,—The height of
the barometer at the time of manipulation is noted. Remember-
SPECIFIC GRAVITY. 605
ing that the volume which a gas occupies varies inversely as the
pressure to which it is subjected (Boyle’s Law, p. 46), a simple
calculation shows the volume which the gas eased occupy at 760
millimetres (or 29.92 inches), the standard pressure. Thus 40
volumes of a gas at 740 millimetres pressure are reduced to 39
when the pressure becomes 760 millimetres (or 90 vols, at 29 inches
pressure becomes 87 vols. at 30 inches).
Correction of the Volume of Gases for Temperature.—This is done
in order to ascertain what volume the gas would occupy at 32° F.
(0° C.). Gases are equally affected by equal variations in temper-
ature (Charles). They expand about 0.3665' percent, (vt y) of
their volume af the freesing-point of water for every C. degree
(0.2036 percent,, or yhy for every F. degree) that their temperature
is rnised above that point (see Charles’s Law, p. 46). Thus 8
volumes of gas at 0° C. will become 8.293 at 10° C; for if 100
become 108,665 on being increased in temperature 10° C., 8 will
become 8,293 (or if 100 become 102.036 on being inereased 10° F.,
8 will become 8,168. ~
Vapor-density.—V apors are those gases which condense to liquids
at ordinary temperatures. What is commonly called the vapor-
density of a substance is really the specific gravity or relative den-
sity of its vapor, and is simply the ratio of the weight of any given
volume to that of a similar volume of air or hydrogen at the same
temperature and pressure. But, for convenience of comparison,
this experimental specific gravity is referred, by calculation as just
described for permanent gases, to a temperature of 0° C., and 769
millimetres pressure. A teaspoonful or so of liquid is placed in a
weighed flask about the capacity of a common tumbler and having
a capillary neck; the flask is immersed in an oil-bath and heated to a
temperature considerably above the boiling-point of the liquid ; at
the moment vapor ceases to escape, the neck is sealed by a blow-pipe
flame, and the temperature of the bath noted; the flask is then
removed, cooled, cleaned, and weighed ; the height of the barom-
eter is also taken. The neck of the flask is next broken off
beneath the surface of water (or of merc ury), which rushes in and
fills it, and the flask is again weighed with its contenta, by which
its capacity in cubic centimetres is found. From these data the
volume of vapor yielded by a given weight of liquid is ascertained
by a few obvious calculations. The capacity of the globe having
been ascertained, the weight of an equal volume of air® is caleu-
lated. This weight of air is deducted from the original weight of
the flask, which gives the true weight of the glass, The weight
' Corrected for the difference between the merourial and air-thermom-
eters, the coefficient of expansion of air ia 0.003656 (Miller). The co-
efficient of expansion of different gases varies very slightly, being some-
what higher for the more liquefiable gases.
? | cubic centimetre of air at 0° C. and 760 millimetres weighs 0.001293
gramme,
606 QUANTITATIVE MEASUREMENTS,
of the glass is next subtracted from the weight of the flask and
contained vapor (now condensed), which gives the weight of
material used in the experiment, The volume which this weight
of material occupied at the time of experiment is next corrected
for temperature (to 0° C,) and pressure (760 millimetres) in the
manner just described, The weight of a similar volume of hydro-
gen is next found.’ The weights of equal volumes of hydro-
gen and vapor being thus determined, the density of the vapor, as
compared with that of hydrogen = 1, is easily calculated. This
process of finding the weight of a given volume of vapor was in-
troduced by Dumas. Gay-Lussac’s method consists in determin-
ing the volume of a given weight: it has been improved by Hof-
mann. An easy and excellent method by V. and C. Meyer eon-
sists, like that of Gay-Lussac, in determining the volume of the
vapor of a given weight of a fluid or solid, but differs from it in
so fur that the volume of the vapor is ascertained by measuring
an equal volume of air which the vapor is made to displace.
As this method is the one which is now most commonly em-
ployed a somewhat detailed description of it may be given here,
Vapor-density Determination by Meyer's Method.—The special
form of apparatus employed is represented in Fig, 68, and con-
sists essentially of the three following parts :—1. The inner ves-
sel a, which is really a flask having an elongated body, a very
long narrow neck, and a nearly capillary side delivery-tube 6;
2. The outer jacketing vessel f, which also is a flask of special
shape; and 3. The measuring apparatus. In order to carry out
a vapor-density determination, a suitable liquid, of boiling-poimt
considerably higher than that of the substance under examination,
is placed in the outer vessel and is there heated until it is in
brisk ebullition and its vapor is condensing close to the top of the
vessel. By this means the greater part of the inner vessel is
surrounded by a jacket of hot vapor and is thereby raised to a
practically uniform temperature. Prior to this preliminary heat-
ing operation, the outlet end of the deliyery-tube 6 has been
placed beneath the water in “the vessel d, and, owing to the ex-
pansion of the air enclosed in a, bubbles make their escape at
the surface of the water. During the heating, a weighed
quantity of the substance to be examined (contained in a very
small stoppered bulb) is suspended in the widened upper portion
11 litre (1000 enbie centimetres) of hydrogen at 0° C. and 760 milli-
metres (the baromete 1% being at o Cc) weighs 0.09 vromme, 100 eubie
inches of hy drogen at 32° F, we igh 2.265 seTuins ; at 60° F. 2.143 grains (the
barometer bei ng 30 inches at 60° F. in both cases), 100 ‘eubie inches of
airat 32° F. weigh 32.698 grains ; at 60° F., 30.995 (barom. 30 inches at 60°
F.). 1 cubic inch of mes r weighs 252. ASS grains (( a 252.279) at
62° F,, and 30 inches. 1 gallo of ante r contains 2774 (277.274 at G20 F.)
cubic inches. 1 cubic foot contains about 64 gallons.
SPECIFIC GRAVITY, 607
of the inner vessel, just below the stopper e¢ which, when replaced,
closes the mouth of the vessel. As soon as bubbles no longer
escape from 4, the apparatus is ready for an experiment. The
tube ¢, previously filled with water, ia next inverted over the outlet
end of 6 and then, by aid of a wire which
passes, air-tight, through the stopper ¢, the Fig, 68.
bulb containing the substance is released,
and falls to g, where a thin layer of asbestos
has previously been placed to prevent its
cracking the glass of the inner vessel, As
a result of the high temperature at g, the
stopper of the bulb is forced out and the
whole of the liquid gradually becomes con-
verted into vapor (which should not more © g
than half fill the lower part of a), This
vapor drives out of a, and into the measur-
ing-tube, a quantity of air equal in volume
to that which itself occupies.
At the close of the experiment, the vol-
ume of the air in the measuring-tube is
read off and reduced to standard tempera-
ture and pressure. The corrected volume
represents, theoretically, the space which the
weighed quantity of substance would occupy
if it existed as vapor under normal conditions
of temperature and pressure. From the
results thus obtained, a simple calculation
gives the vapor-density.
Determinations of the specific gravities
or relative densities of gases, and of the
vapor-densities of liquids (or of vaporiz-
able solids), are carried out for the purpose
of fixing the molecular weights of these
various substances in the state of gas or
vapor, and of assigning to them molecular
formule, As already explained in the
Section on the General Principles of Chem- |
ical Philosophy, the relative molecular mF
weights of substances in the gaseous state (p3=
are proportional to their relative densities Ss ft
(see pp. 54, 55). The molecular weight of A
hydrogen is chosen=2 as standard for the meres partis.
comparison of the molecular weights of
other substances in the gnseous state; butsince the relative molecular
weight and the relative density of each substance are proportional
to each other, it follows that the number representing any molec-
ular weight, in terms of the standard just mentioned (hydrogen
=2), may be obtained by doubling the number representing the
SRR PRRR RSPR PETER eee
_ - 2
Al
'f
608 QUANTITATIVE MEASUREMENTS.
relative density. The molecular weight of a substance thus hay-
ing been ascertained, and the quantitative composition and em-
pirical formula also having been determined (see p, 60), the molee-
ular formula can be assigned. The quantitative value of any
molecular formula must agree with the experimentally determined
molecular weight of the substance which it purports to represent.
Thus the determination of the quantitative composition of ben--
zene and the necessary calculation lead to the empirical formula
CH, But this formula would represent a substance of molecular
weight 12.91, or of density (us vapor) not 6,455, whereas the
molecular weight of benzene as ascertained by doubling the
number representing its vapor density is 77.46 (i.¢,, 38.73% 2),
The only formula which corresponds to this molecular weight, as
deduced from the vapor-density, is C,H,, and this, Mi dy
is assumed as the molecular formula for benzene,
QUESTIONS AND EXERCISES.
What is meant by the specific gravity or relative density of a substance?
—In speaking of light and heavy bodies specifically, what standard of
comparison is conventionally employed ?—How are specific gravities ex-
pressed in figures?—Why should specific gravities be taken at one con-
stant temperatmre ?—How does the buoyancy of air affect the apparent
weight of any material as ascertained by aid of the balance?}—Give
a direct method for taking the specific gravity of liquids.—A certain
bottle holds 150 parts, by weight, of water, or 135.7 of diluted aleohol ;
show that the specific gravity of the latter is 0.0046.—An imperial fluid
ounce of a liquid weighs 3664 grains; prove that its specific gravity is
0.835.—Equal volumes of benzole and glycerin weigh 34 and 49 mes
respectively, and the specific gravity of the benzole is 0.850; show that
the specific gravity of the glycerin is 1.225.—Explain the process em-
ployed in taking the specific gravities of solid substances in mass and in
powder.—State the method by which the specific gravity of a light body,
such as cork, is obtained.— What modifications of the usual method are
necessary in ascertaining the specific gravities of substances soluble in
water (—How are the specific gravities of gases determined }—What are
vapor-densities ’—Describe Meyer's vapor-density eigen what
law can the volume of a gas, at any required pressure, be ded from
its observed volume at another pressure ?—To what extent will 78 vol-
umes of a gas at 29.3 inches barometric pressure alter in volume when the
pressure is 30.2 inches ?—Write a short account of the means by which
the volumes of gases are corrected for temperature,—At the tempermture
of 15° C. 40 litres of a gas are measured. To what volume will this gus
contract on being cooled to the freezing-point of water (0° C.)?—Anawer,
37.916 litres.
Memorandum.—The next subjects of experimental study
will be determined by the nature of the student's future pur.
QUANTITATIVE ANALYSIS. 609
suits. In most cases the operations of quantitative analysis
will engage attention. These should include both volumetric
and gravimetric determinations ; and some details concerning
both of these modes of marking determinations are given in
the following pages.
QUANTITATIVE ANALYSIS.
INTRODUCTORY REMARKS.
General Prineiples—The proportions in which chemical
substances unite with each other in forming compounds are
definite and invariable (p. 50). Quantitative analysis is
based on this law. When, forexample, aqueous solutions of a
silver salt and a chloride are mixed, a white curdy precipitate
is produced containing chlorine and silver in atomic propor-
tions—that is, 35.18 parts of chlorine to 107,12 of silver. No
matter what the chloride or what the silver salt, the resulting
silver chloride is invariable in composition. The formula
Ag(l isa convenient symbolic representation of this compound
in these proportions. In the case of any known weight of a
compound, of which the quantitative composition has been
determined previously, the quantities of its constituents
can be ascertained by simple calculation. Suppose, for
instance, 8.53 parts of silver chloride have been obtained
in some analytical operation: this quantity will be found
by calculation to contain 2.109 parts of chlorine and
6.421 of silver. For if 142.3 (the formula weight) of silver
chloride contain 35.18 (the atomic weight) of chlorine, 8.53
B5.18X8.53 9 199 of
142.8
chlorine; and if 142.3 of silver chloride contain 107.12 of
silver, 8.53 of silver chloride will contain Lah —6,421
of silver. To ascertain, for example, the quantity of silver
in a substance containing, say, silver nitrate, all that is neces-
sary is to take a weighed quantity of the substance, dissolve
it, precipitate the whole of the silver by adding hydrochloric
acid or other soluble chloride until silver chloride is no longer
produced, collect the precipitate on a filter, wash, dry, and
39
of silver chloride will contain
610 QUANTITATIVE ANALYSIS.
weigh. The quantity of silver in the dried chloride, ascer-
tained by calculation, is the quantity of silver in the weighed
portion of substance on which the operation was conducted ; a
further simple calculation gives the quantity percent.—the
form in which the results of quantitative analysis are usually
stated, Occasionally a constituent of a substance admits
being isolated and weighed in the uncombined state. Thus
the quantity of mercury in a substance may be determined
by separating and weighing the mereury in the metallic con-
dition ; if the substance under examination be calomel (HgCl)
or corrosive sublimate (HgCl,), the proportion of chlorine may
then be ascertained by calculation (Hg—198.5 ; Cl=35.18),
or a chloriné determination may be made.
Nature of Gravimetric Quantitative Analysis.—As stated above,
an element may sometimes be isolated and weighed and its quantity
thus ascertained ; or it may be separated and weighed in combi-
nation with another element whose combining proportion is well
known ; this is quantitative analysis by the gravimetrie method,
Nature of Volumetric Quantitative Analysis. —Volumetric opera-
tions depend for success on some accurate initial gravimetric opera-
tion. A weighed quantity of a pure salt is dissolyed in water or
other fluid, and the solution is made up toa definite volume so as to
obtain a standard solution, Quantitative analysis by the volu-
metric method consists in ascertaining the volume of the standard
liquid which must be added to the substance under examination
before a given effect is produced. Thus, for instance, a solution
of silver nitrate of known strength may be used in experimentally
determining an unknown quantity of a chloride in any substance.
The silver solution is added to a solution of a definite quantity of
the substance until flocks of silyer chloride are no longer precipi-
tated: every 107.12 parts of silver added (or 168.69 of silver
nitrate) indicate the presence of 35.18 of chlorine, or an equiva-
lent quantity of any chloride. The preparation of a standard
aolution, such as that of the silver nitrate to which allusion it
here made, requires much care; but once it is prepared, certain
analyses can, as already indicated, be executed with far greater
rapidity and ease than by gravimetric processes.
In the following pages an outline of volumetric and gravimetric
quantitative analysis is given, The scope of this work precludes
any attempt to describe all the little mechanical details observed
by quantitative analysts; essential operations, however, are so fully
treated that careful manipulators will meet with little difficulty,
VOLUMETRIC ANALYSIS. 611
VOLUMETRIC ANALYSIS.
Preliminary Note.—Great care should be observed in
selecting a fair sample of any bulk of material that is to be
examined either by volumetric or gravimetric analysis. Ifthe
whole quantity is in separate parcels, and if there is any ground
for believing that the parcels differ in quality, they should,
if practicable, be carefully mixed, or, technically, * bulked.”
Small portions should be taken from different parts of the
resulting heap and well mixed in a mortar or other vessel,
or, in certain cases, dissolved, and the solution well stirred or
shaken. A specimen of the powder, or a portion of the solu-
tion, may then be selected for analysis,
Introduction.—The operations of volumetric analysis con-
sist (a) in carrying out some definite chemical reaction, already
well known to the operator, with (6) definite quantities of sub-
stances or salts; (c) the exact termination of the reaction between
the two salts or substances being ascertained—usually by some
chemical indicator (litmus, starch, ete.). A portion of the sub-
stance to be tested is carefully weighed and dissolved. To this
solution there is gradually added the second substance contained
in the testing fluid, commonly termed the Standard Volumetric
Solution. The usefulness, and indeed the preparation, of this
Standard Solution is founded (as already indicated on page 610)
on some accurate initial gravimetric operation, A weighed quantity
of a pure salt is dissolved in water, and the solution is made up
to a definite volume so as to obtain a Standard Volumetric Solu-
tion. Accurately measured yolumes of such aStandard Volumet-
ric Solution will obviously contain just as definite quantities of
the dissolved salt as if those quantities were weighed in a balance;
and as measuring occupies less time than weighing, the volumetric
operations can be conducted with great economy of time as com-
pared with the corresponding gravimetric operations, A standard
solution is one containing a known quantity of substance in unit
volume.
A normal solution is a solution one litre of which represents,
more or less directly, the chemical value or activity of the atomic
weight of hydrogen taken in grammes (H=1, that is, 1 gramme),
A fenth-normal solution ia one-tenth the strength of a normal solu-
tion, A hAundredth-normal solution is one-hundredth the strength
of a normal solution, The normal solution of iodine (H=1,
[=125.0) would contain 125.9 grammes of iodine per litre; that
quantity being capable of displacing, or otherwise being equal in
chemical activity to, 1 gramme of hydrogen. The official Volu-
612 VOLUMETRIC ANALYSIS.
metric Solution of Iodine containing 12.59 grammes per litre, is a
tenth-normal solution. The official Volumetric Solution of Silver
Nitrate containing 16.869 grammes of the salt in one litre
(AgNO, = 168.69 + 10), is a tenth-normal solution. The offi-
cial Volumetric Solutions of Sodium Hydroxide (NaOH = 39,76
grammes per litre), and Sulphuric Acid (HSO, =97.36 = 2,
that is, 48,675 grammes per litre), are normal solutions. Solutions
of hydrochloric acid containing 36.18 grammes of hydrogen
chloride (HCl = 36.18) per litre; of oxalic acid containing 62.55
grammes of crystallized oxalic acid (H,C,O,, 2H,O=125, 10 2)
per litre; and of phosphoric acid containing 32.48 grammes of
hydrogen phosphate (11,PO,= 97.29 + 3) per litre, would be
normal solutions. The molecule of potassium bichromate
(K,Cr,O, = 292,28) in presence of an acid, yields three atoms of
oxygen available for direct oxidation, or for union with six atoms
of hydrogen, therefore a solution of 48.71 grammes (292. 28 —- 6)
per litre would be a normal solution. The official Volumetric
Solution of Potassium Bichromate contains one-tenth of this
quantity, and is, therefore, a tenth-normal solution, The official
Volumetric Solution of Sodium Thiosulphate is tenth-normal, for
the molecular weight in grammes (Na,5,0,, 5H,0=246.46) loses
one atomic weight of sodium in grammes (Na=22.88) when
attacked by one atomic weight of iodine in grammes (I=125.9),
a quantity equal in chemical value or activity to the atomic weight
of hydrogen in grammes (H=1); and as the official Thiosulphate
Solution, like the official Iodine Solution, contains only one-tenth
of that hydrogen equivalent in grammes, it is a tenth-normal
solution,
Apparatus.
The only special vessels necessary in volumetric quantitative
operations are :—1l. A one-lifre flask (Fig. 69) which, when filled
toa mark on the neck, contains one litre (1000 cubic centimetres, or
rather 1000 grammes (of water'); it serves for preparing solutions
in quantities of one litre. 2. A tall cylindrical graduated jar
(Fig. 70) which, filled to the highest graduation, contains 1000
grammes of distilled water divided into 100 equal parts; it serves
for the measurement and admixture of decimal or centesimal parts
of the litre. 8. A graduated tube or buretée (Fig. 71), the marked
portion of which, when filled to‘‘0,"’ holds 100 grammes of distilled
water, and is divided into 100 equal parts, or 50 grammes and
divided into equal parts, each of which is taken as corresponding
'A cubic centimetre is the volume occupied by one gramme of distilled
water at its point of greatest density, namely, 4°C., Metric Measure-
ments, however, are officially taken at 25° C. (77° F.).
APPARATUS. 613
to 1 cubic centimetre, with subdivisions, each subdivision being
further subdivided; it is used for accurately measuring small
volumes of liquids. A stopcock is fitted to the contracted portion,
or other modes of arresting the flow of liquid may be adopted.
The accurate reading of the heightof a solution in the burette
is a matter of great importance ; it should be taken from the
bottom of the curved surface, or meniscus, of the liquid. When
reading the burette, the eye should be on the same level as the
bottom of the meniscus. In the case of a colored solution, when
the bottom of the meniscus cannot be clearly seen, the I
must be taken from the surface of the liquid.
Fig. 69. Fia. 70. Fie, 71.
A litre flask, A bnrette, ete,
A litre jar,
Occasionally a hollow glass float or bulb (Erdmann’s float, see
Fig. 71) is employed, of such a width that it can meve freely in the
tube without undue friction, and so adjusted in weight that it shall
sink to more than half its length in any ordinary liquid. A fine
line is scratched around the centre of the float; this line must
always be regarded as marking the height of the fluid in the
burette. In charging the burette, a solution is poured in, not
until its surface is coincident with 0, but until the mark on the
float is coincident with 0.
The exercises in Volumetric Analysis described in the following
pages are illustrative only and do not deal exhaustively with the
application of volumetric methods to all the chemical substances
employed in pharmacy. Volumetric methods, as applied to offi-
cial substances, are fully described in the U. 8, Pharmacopoia,
and for further information respecting them the student is referred
to that work.
VOLUMETRIC ANALYSIS.
DETERMINATION OF ALEKALIES.
VOLUMETRIC SOLUTION OF SULPHURIC ACID,
(Sulphuric Acid, HSSO,= 97.35.)
The Sulphuric radical, being bivalent, and most of the metals
contained in the salts which are determined by means of standard
sulphuric acid solution being univalent, it is convenient that each
litre of this solution should contain half a molecular weight (the
hydrogen equivalent), in grammes, of the acid (H,SO, = 97,35,
and 97.35 + 2= 48.675). <A solution of this strength is a normal
solution.
As it is not always easy to obtain pure sulphuric acid, the
solution may be made from the commercial acid by mixing 50
grammes with five or six times its volume of water and after
cooling adding sufficient water to make u litre of solution. The
exact quantity of acid present in this solution may then be deter-
mined by titration with pure sodium carbonate, making use of the
following memoranda;—
Na,CO, + H,SO,
=<——“y —
2)105.81 2)97.35
52.655 48.675
Pure anhydrous sodium carbonate can be prepared readily, for
commercial bicarbonate is usually of such purity that when a
small quantity is heated to redness for a quarter of an hour,
the resulting carbonate is practically free from impurity. The
bicarbonate should, however, be tested, and if more than traces
of chlorides and sulphates are present, these may be removed by
washing a few hundred grammes, first with a saturated solution of
sodium bicarbonate, and afterward with pure distilled water.
After drying, the salt is ready for ignition—a few grammes in a
small crucible.
About half a gramme of the sodium carbonate is accurately
w eighed and placed in a half- -pint flask, around the neck of which
twine has been wound to protect the fingers when the heated yeasel
is s shak aken by the operator (page 116), The salt is dissolved in
to about one- third the c apacity of the flask, and a few drops
of the indic ator, blue solution of litmus, are added. The acid
solution to be «* standardized’ is the n poured into a burette and
run there from into the flask ‘until the reddened litmus indicates the
presence of a free acid. This will be due in the first place to car-
bonic acid liberated and remaining dissolved in the solution;
hence the contents of the flask must be gentl y boiled for several
minutes to expel carbonic anhydride, when the blue color will
VOLUMETRIC DETERMINATION OF ALKALIES. 615
have returned. More acid is then run in until the mixture, after
boiling, remains of a neutral color, indicating that just enough
acid has been added to complete the reaction expressed in the
foregoing equation.
Let it be supposed that 0.6 gramme of sodium carbonate was
taken, and that this required 11 Ce. of sulphurie acid solution,
how many Ce, of this solution would contain 48,675 grammes of
pure sulphuric acid; or, what is equivalent in the reaction, how
many Cc. would be required to neutralize 52.65 grammes of
sodium carbonate? By rule of three, 0.6 : 11:: 62.65: 2,
and « = 965,25; therefore in the example taken 965.25 Cc. are
equivalent to 52.65 grammes of sodium carbonate, and contain
48.675 grammes of sulphuric acid.
This solution may be diluted with water, every 965, 25 Cc. to be
diluted to 1000 Ce., so that 1000 Ce, shall contain 48,675
grammes of sulphuric acid, or it may be used as it is and the
necessary correction applied,
Borax, purified by recrystallization, is recommended by Rim-
bach for standardizing acids, in place of sodium carbonate.
When it is used, the indicator employed should be methyl! orange,
which is not affected by boric acid.
The following substances may be tested conveniently by meuns
of the standard solution of sulphuric acid :-—
Solutions of Ammonia.—Two or three grammes of dilute, or about
1 gramme of stronger ammonia water, are convenient quantities to
operate upon. The weighing is most conveniently accomplished
by taking a small stoppered bottle containing half an ounce or 80
of the substance, and having ascertained its total weight, trans-
ferring about the quantity desired to the flask in which the esti-
mation is to be conducted, and again weighing the bottle with
what remains in it. The difference is the exact quantity taken.
The weighing of the ammonia solution having been accomplished,
water is added, to about one-third the capacity of the Hask (or,
better, the ammonia is added to water already in the flask), and
a few drops of solution of litmus are introduced. The titration is
then conducted as described before, except that no heat is
employed.
2NH.OH + H,80, = (NH,),80, + 2H,0
—_——— ——__
2)69.62 2)97,35
34.81 48.675 =grammes in 1000 Ce. of normal solution.
2NH, + H,SO, = (N H,),50,
2)88.86 2)97.55
16,98 48.675=grammes in 1000 Ce, of normal solntion.
616 VOLUMETRIC ANALYSIS,
1000 Ce of normal solution, or its equivalent of a solution of
any other concentration, would, according to this equation, neu-
tralize 16.98 grammes of ammonia gas (NH,) or 34.82 grammes
of ammonium hydroxide (NH,OH),. If 3 grammes of ammonia
solution had been taken, and it had required 15 Cec. of normal
sulphuric acid solution, then the quantity of ammonia gas or
ammonium hydroxide it ‘contained would be seen by the following
calculations :—
1000 Ce.: 16.93 g¢. NH, :: 15 Ce.: 2 = .254 grammes NH,
1000 Ce. : 34.81 g. NH,OH :: 15 Ce.:2 = .522 grammes NH,OH
Three grammes, then, would contain .254 grammes of the gas, or
.§22 grammes of ammonium hydroxide. Or in percentages;—
3g. sol. :.254 g. NH :: 100g. sol.:rg. NH, = 8&47@NH
3g. sol, : .522 g. NH,OH :: 100 g. sol.: eg. NH HO = 17.4%
The solution would therefore contain 8.47 percent, of ammonia
gas (NH,) or 17.4 percent. of ammonium hydroxide (NH,OH),
If the sulphuric acid solution was not of full standard, the number
of Ce. which contained 48.675 grammes of sulphurie acid, which
was, in fact, equivalent to 1000 Ce. of normal solution, might be
substituted for 1000 Cc. in the preceding calculations,
A comparison should now be made with the requirements of the
Pharmacop@ia. It is useful to express results as percentage of
substance of pharmacopeial strength in the material examined,
Thus the U. 8. Pharmacopceia requires ammonia water to contain
10 percent. by weight of the gas(NH,). The solution supposed to
have been operated on contained 8.47 per cent. NH,, therefore it
contains 84,7 percent. of the ammonia water of the ’ 8. Pharma-
copeia,"
1 Extremely minute quantities of ammonia—1 part in many millions
of water—may be determined volumetrically by adding excess of a color-
less, strongly alkaline, solution of mercuric iodide and potassium iodide,
Mercurie Potassiam Iodide Test Solution, U.8. P., or“ Ee ee
then in a similar vessel, containing an equal amount of pure water wi
excess of the Nessler reagent, imitating the depth of yellow or reddish-
yellow color thus produced by adding a solution containing a known
quantity of an ammonium salt. The quantity of ammonia thus added
represents the quantity in the original liquid.
The Nessler Reagent —A litre may be made by dissolving 50 grammes
of potassium iodide in 50 Ce. of water adding a saturated solution
of mercuric chloride until the precipitate of mercuric iodide remains
undissolved even by the ‘aid of rapid stirring, adding 150 grammes of
potassium hydroxide and di ilnting to one litre, After the precipitate has
subsided, the clear liquid is drawn off for use, and should be preserved in
a well. closed. bottle: the clear liquid | is then decanted for use. The reae-
tion of this Nessler test with ammonia is as follows :—
NHs + 2Hgl: + 3KOH = NHg:l + 3KI + 3,0
Mercuric Potassium Iodide, without alkali, is commonly known as
Mayer's Reagent, UgK ls. A tenth-normal solution isa convenient one to
tise.
VOLUMETRIC DETERMINATION OF ALKALIES. 617
Stronger Ammonia water, U. 8. P., contains 28 percent. by
weight of ammonia gas (NH,).
Note.—The calculations just described for ammonia are similar
to those employed throughout volumetric analysis; they will not
be repeated, therefore, in the case of every substance,
‘‘Ammonium Carbonate.”,-—The reaction indicated by the fol-
lowing equation occurs between commercial ammonium carbonate
and sulphuric acid:—
2N,H,,C,0, + 3H,80, = 3(NH),SO0, + 2H,O = 4CO,
—<$<— —$<—$$—$—" —,—
6)312, 02 6)292.05
62.03 48.675 = grammes in 1000 Ce, of normal solution.
About 1 gramme is a convenient quantity to operate upon.
Solution of litmus is the indicator, and the titration is conducted
at a temperature just short of boiling. The determination is not
very satisfactory, because the heat employed, while scarcely suffi-
cient to expel the carbonic anhydride, is enough to occasion loss
of ammonium salt. To avoid error, add excess of the normal acid
solution and thus fix every trace of ammonia; then gently boil to
get rid of carbonic anhydride; bring back the liquid to neutrality
by an observed volume of normal alkaline solution, and deduct an
equivalent volume of acid from the quantity first added.
Spiritus Ammonia Aromaticus, U. 8. P.—The determination of
ammonia in this preparation is quite analagous to its determination
in the solutions of ammonia already described.
Borax.—Two or three grammes is a convenient quantity.
Na,B,0,,10H,O + H,SO, = Na,SO, + 4H,BO, + 5H,O
—SSo—
2)379.32. 2)97,35
189.66 48.675 —grammes in 1000Ce, of normal solution.
Solution of litmus ia the indicator, and the titration may be
carried on without heat. The liberation of boric acid colors the
litmus wine-red, This is not regarded, the titration being con-
tinued until the bright red due to the action of free sulphuric
makes its acid appearance, Methyl orange may be used as the
indicator, a8 it is not affected by boric acid,
Lime Water, and Syrup of Lime.—Measure about half a litre
of lime water, or weigh about 25 grammes of the syrup. The
following equations give quantitative expressions of the reactions: —
Ca(OH), + HSO, = CaSO, + 2H,O
———— —
2)73.56 2)97.35
86.78 48,675 —grammes in 1000 Ce. of normal solution.
618 VOLUMETRIC ANALYSIS.
Or, CaO + H,SO, = CaSO, + H,O
—— ——"
2)55, 68 2)97.35
27. 84 48.675 = grammes in 1000 Ce. of normal solution.
Litmus is used as an indicator, One litre of Lime Water,
U. 8. P., contains about 1.4 gramme of calcium hydroxide,
Ca(OH ),, equal to about 1.1 gramme of quicklime, CaO, Ten
fluid ounces contain 64 grains of calcium hydroxide,
Sodium. Potassium and Sodium Hydrowxides, Potassium and
Sodium Carbonates and Bicarbonates.—Litmus is the indicator
throughout and heat is used in all cases, for the caustic alkalies
always contain some carbonate.
2Na + H,50, = H, + Na So,
—— —,—
2)45.76 2)97, 35.
22.88 48.675 = grammes in 1000 Ce. of normal solution.
2KOH + H.S0, = K,SO, + 2H,O
2)111.48 = 2)97.35
ho. 74 45.675 = grammes in 1000 Ce, of normal solution.
2NaOH + H,SO, = NaSO, + 2H,O
2)79, 52 2)97.385
39.76 48. 675 = grammes in1000 Ce. of normal solution.
KC 0, + H,SO ,_r+= KS0, + CO, + H,O
YUB7.27 =. 2) 97.35
68,685 48.675 = grammes in 1000 Ce. of normal solutly »
'
Na,CO, + HSO, = NaSO, + CO, +H,0
—— —
2)105.381 2)97.35
A655 48.675 = grammes in 1000 Ce. of normal solution,
Or, Na,CO,,H,O 4. H,SO, = NaSO, + CO, + 11H,0
¥ =,
7
)97.85
2)128.19 2
61,595 4 8.675 - grammes in 10%) Ce, of normal solution
2KHCO, + H,S0,= K,SO, + 200, + 2H,0
2)198, 82
Hy 41 48.675 = grammes in 1000 Ce. of normal solution.
VOLUMETRIC DETERMINATION OF ALKALIES. 619
2NaHCO, + HSO, = Na,SO, + 200, + 2H,0
—,—" ——
2)166.86 2)97.35
83.438 48.675 = grammes in 1000 Co. of normal solution.
Convenient quantities to operate with are: of sodium, 0.4 or
0.5 gramme, placed on 10 or 20Cc. of water in a basin, the latter
being immediately covered with a glass plate to preserve the face
and hands from any caustic spurtings and to prevent loss of soda;
of potassium hydroxide, 1 gramme; sodium hydroxide, 0,5 to |
gramme; potassium carbonate, or bicarbonate, 1 to 2 grammes;
sodium carbonate, or bicarbonate, 2 to 3 grammes; dried sodium
carbonate, 0.5 to 1 gramme; and of solutions a corresponding
quantity.
Potassium and Sodium Tartrates and Citrates.—When alkali-
metal tartrates or citrates are burned in the open air, the whole
of the metal remains in the form of carbonate. Each formula
weight of a normal tartrate gives one formula weight of carbonate,
and twice the formula weight of an acid tartrate gives one formula
weight of carbonate. Advantage is taken of these reactions to
determine indirectly the quantity of citrate or tartrate in presence
of substances with which they are generally associated. One or
two grammes of any of these salts is a convenient quantity to
operate upon, The ignition may be conducted in a platinum or
porcelain crucible. A low red heat only should be used, and the
vessel removed when complete carbonization has been effeeted—
that is to say, when nothing remains but the carbonate and free
carbon, The mixture is then treated with hot water, and the
carbon separated by filtration. If too little heat has been used,
and carbonization is not complete, the filtrate will be more or less
colored, If this should be the case, the operation must be repeated
with a fresh quantity of material. The carbonate is titrated in the
usual way, The following equations explain the reactions:—
(K,C,H,0,),,H,O + 50, = 2K,CO, + 6CO, + 5H,O
4)467.16 4) 274.54
116.79 68.635 [__ eauly. to 1000 Ce, of
i normal sulphorte acid sol.
2KHC,H,O, + 50, = K,CO, + 700, + 5H,O
2)378.56 2)137.27
: iv. to 1000 Ce of
186.78 68.635 { nore sulphuric acid Bol,
2K,0,H,0, -+ 90, = 8K,CO, + 900, 4+ 5H,O
—$ ———
6)608.4 6)411.81_
\ Or juiv. to 1000 Ce, of
101.4 68.635 { wecnernad wap ees acaba wi:
620 VOLUMETRIC ANALYSIS.
2)K NaC,H,0,,4H,0) + 50, = 2KNaGO, 4 6CO, + 12H,0
eee oS RAS
4)560.36 4)242.58
140.09 60. 645 { ., oaUl. toe a oe
It will be readily understood that in the first (for example) of
the reactions just represented 116.79 parts by weight of potassium
tartrate are equivalent to 68.6385 of potassium carbonate; and as
in a previous reaction it has been shown that 68.635 ‘parts by
weight of potassium carbonate are equivalent to 48.675 of sul-
phuric acid, it follows that 116.79 parts by weight of potassium
tartrate are equivalent to 48.675 of sulphuric oi Hence 116.79
grammes of potassium tartrate are equivalent to 48.675
of sulphuric acid, or to 1000 Cec. of the standard solution of
sulphuric acid. If the substance under examination be a erude
sample of potassium tartrate, and if the number of Ce. of sul-
phuric acid used for 2 grammes of the sample has been 15 Ce.,
then as 1000 Ce. of the acid solution are equivalent to 116. 79
grammes of potassium tartrate, 15 Cc. of the solution are equiya-
lent to 1.75 gramme of potassium tartrate. As 2 grammes of the
sample contain 1.75 of real potassium tartrate, the tartrate
examined contains 87.5 percent. of real tartrate. Commercial
samples of this salt are practically pure asa rule. If calcium sul-
phate be present in such tartrates or citrates, loss of potassium
carbonate will ensue, potassium sulphate being formed. In
examining acid potassium tartrate, which is the salt most likely
to contain calcium sulphate, direct titration with volumetric solu-
tion of sodium hydroxide may be employed (#ee next section),
Seven or eight percent. of calcium tartrate is commonly present
in commercial cream of tartar. The U. 8. Pharma
requires that the salt should contain not less than 99 percent, of
pure potassium bitartrate.— Rochelle Salt and Sodium Benzoate
should each be pure within 1 percent.
Notes.
Alkalimetry.—The foregoing processes are often spoken of as
those of a/kalimetry (the measurement of alkalies),
Solution of Litmus may be prepared by boiling in water pow-
dered litmus, which has been successively extracted with several
quantities of boiling alcohol and with cold water. The solution
may be kept in a stoppered bottle, and occasionally exposed to
the air.
Weighing.—In the case of substances which are liable to alter
by exposure to air, it is important that a selected quantity should
be weighed, rather than that selected weights from the weight-box
be accurately balanced by material, the former operation -
ing much the shorter time, The procedure adopted for Solutions
of Ammonia (p. 615) may also be employed.
VOLUMETRIC DETERMINATION OF ACIDS. 621
QUESTIONS AND EXERCISES,
On what fundamental laws are the operations of quantitative analysis
based ?—What is the general nature of gravimetric quantitative analysis?
—Explain the principle of volumetric quantitative analysis ?—Define (1) a
standard and (2) a normal solution.—Describe the apparatus used in vol-
umetric determinations.—One hundred cubic centimetres of solution of
sulphuric acid contain 4.8675 grammes of hydrogen sulphate; calculate
what weights of potassium bicurbouate and anhydrous sodium carbonate
that volume will neutralize. Ans, 9.939 grammes and 5,266 grammes.—
Show what weight of potassium hydroxide is contained in a solution of
potash 48.02 grammes of which are neutralized by 50 Ce. of normal
solution of sulphuric acid. Ans., 5.80 percent.—Calculate the percentage
of calcium hydroxide in lime water 480 grammes of which are neutral-
ized by 20 Ce. of the volumetric solution of sulphuric acid, Ana,, 0.153.
—Eight grammes of asample of Rochellosalt, after ignition, etc., require
4.3 Ce. of the official sulphuric acid solution for complete neutraliza-
tion ; calculate the centesimial proportion of sodium potassium tartrate
present. Ans,, 95,075.
DETERMINATION OF ACIDS.
In the previous experiments a known quantity of an acid has
been used in determining unknown quantities of alkalies. In
those about to be described a known quantity of an alkali is em-
ployed in determining unknown quantities of acids. The alkali
selected may be either a hydroxide or a carbonate, but the former
is to be preferred; for the carbonic acid set free when a strong
acid is added to a carbonate, interferes to some extent with the
indications of alkalinity, acidity, or neutrality, afforded by litmus,
The alkali most convenient for use is sodium hydroxide, a solu-
tion of which has probably already been made the subject of ex-
periment in operations with the normal! solution of sulphuric acid.
It should be kept in a stoppered bottle, and exposed to air as Jittle
a8 possible,
VOLUMETRIC SOLUTION oF Soprom HYDROXIDE,
(Sodium Hydroxide, NaOH= 39.76.)
This aqueous solution is most conveniently made of such con-
centration that 1000 Ce, contain the formula weight in grammes
of the alkali (NaOQH=39.76). It will be seen from the follow-
ing equation that 39.76 grammes of sodium hydroxide convert
48.675 grammes of sulphuric acid into neutral sodium sulphate.
Therefore one litre of this normal solution, containing 39.76
grammes of sodium hydroxide, will form a neutral solution of sul-
phate with one litre of normal sulphuric acid solution, or with a
622 VOLUMETRIC ANALYSIS.
chemically equivalent quantity of sulphuric acid solution of any
other concentration ;—
H,S0, + 2NaOH = NaSO, + 2H,0
— —,—
2)97.35 2)79.52
48.675=1000 Ce, of normal solution. 389,76—1000 Ce, of normal solution.
If pure sodium hydroxide were at hand, it would only be neces-
sary to weigh 39.76 grammes, dissolve this in water, and dilute to
one litre. But the pure hydroxide cannot readily be obtained.
Therefore weigh about 45 grammes of ordinary sodium hydroxide,
dissolve in water, and when cool make up the volume of the solu-
tion to one litre. Then take, say, 14 Ce., dilute with more water
in « flask, add «a few drops of solution of litmus, and titrate with
sulphuric acid solution of known concentration, Suppose that the
volume of normal acid solution required to neutralize the 14 Cc.
of the soda solution has been 15 Ce., or that an equivalent quan-
tity of acid solation of another concentration has been used;
then, how many Cc. of the soda solution are equivalent in 1000
Cc. of normal acid solution; or, what comes to the same thing,
how many Ce. of the solution contain 39.76 grammes of sodium
hydroxide? Itis found that 933 Ce. of the solution contain,
$9.76 grammes of sodium hydroxide. The solution may etther
be diluted, every 933 Ce. to 1000 Ce., so that it may be normal
(1000 Ce. =89.76 grammes NaOH), or it may be used without
dilution (9338 Cc,=39,.76 grammes NaOH), care being taken to
introduce the necessary correction. It has already been men-
tioned that sodium hydroxide nearly always contains carbonate,
To remove resulting carbonic acid, therefore, the solution should
be heated toward the close of each titration in all the determina-
tions.in which litmus is the indicator. When methyl orange is
used no boiling is required, as that indicator is not affected by car-
honie acid, The following substances are among those which
may be determined with normal sodium hydroxide solution.
Acetic Acid. —Operate upon about 1 gramme of glacial acid,
about 20 grammes of diluted acid, or about 3 grammes of ordi-
nary acetic acid,
HO,H,O, + NaOH = NaC,H,O, + HO
’
s =
_ =S -
—
ae
——— » . r
59,58 -_ 89. 76= 1000 Ce. normal solution.
. | s— | - | * 7 Sey 4 gg ee -
Acetic Acid, U. 8, P., should contain 86 percent. of hydrogen
acetate (HO,H,O,). Diluted Acetic Acid, U. 5. P., 6 percent
(iacidl Acetic Acid, U. 8. P., 99 percent,
VOLUMETRIC DETERMINATION OF ACIDS. 623
.
Citric Acid.—Operate on about 1 gramme. The reaction is
represented by the following equation :—
H,C,H,0,H,O + 8NaOH = Na,C,H,0, + 4H,C
—————
. —_—~—
3)208.5 3)119,28 =
69.5 39. 76-1000 Ce. normal solution,
Hydrochlorie Acid.—Operate on from 1 to 2 grammes of the
concentrated acid, or on about 4 grammes of the diluted acid,
HCl + NaOH = NaCl + HO
= — —._ 9 => —"
36.18 39. 76=1000 Ce, normal solution,
Hydrochloric Acid, U. 8. P., should contain 31.9 percent. of
real acid (HCl); and Diluted Hydrochloric Acid, U. 8. P., 10
percent, Diluted Hydrobromic Acid, U. 8. P., 10 percent.
HBr. ).
\ Lactic Acid, U.S, P., contains not less than 75 percent. of
real acid,
Nitric Acid, —Operate on from 1 to 2 grammes of concentrated,
or on 4 to 5 grammes of diluted acid.
HNO, + NaOH = NaNO, + H,O
—, — ———"
62,57 39. 76=grammes in 1000 Ce. normal solution.
Nitric Acid, U. 5. P., should contain 68 percent.; and Diluted
Nitric Acid., U. 5. P., 10 percent, of hydrogen nitrate (HNO,),
Sulphuric Acid. —Operate upon from 0.5 to 1 gramme of con-
centrated acid, or from 4 to 5 grammes of either Diluted or Aro-
matic Sulphurie Acid,
H,SO, + 2NaOH = NaSO, + 2H,0
2)97, 85 2)79,52
a
48.675 39. 76<grammes in 1000 Ce. normal solution.
Sulphuric Acid, U. 8. P., should contain not less than 92.5
percent,; Diluted, U. 8. P., 10 percent.; and Aromatic, the equiy-
alent of 20 percent. of hydrogen sulphate (H,SO,).
Turtarie Acid.—Operate upon about 1 gramme of the acid. The
following equation represents the reaction :-—
H,C,H,O, + 2NaOH = Na,C,H.0O, + 2H,0
ee ——_=E———
2)148, 92 2)79, 52
74.46 $9.76 = grammes in 1000 Ce, normal solution,
Notes, —1. Pure acetates, citrates more especially, tartrates, and
some other organic sults, haye an alkaline action on litmus, but
=
624 . VOLUMETRIC ANALYSIS.
not to an important extent. If the sodium hydroxide solution be
added to acetic, citric, or tartaric acid, containing litmus, until
the liquid is fairly blue, the operator will obtain fairly trustworthy
results ; but in delicate experiments turmeric or phenol-phthalein
should be used instead of litmus. Phenol-phthalein is produced by
interaction of phenol and phthalic anhydride. Its solution in aque-
ous alcohol yields an intense red color with potassium or sodium
hydroxides, hence may be used as an indicator of the termination
of volumetric reactions, especially those with organic acids,
Phenol-phthalein Test Solution, U. 5S. P., is made by dissolving
1 gramme of phenol-phthalein in 50 Ce, of alcohol and 100 Ce.
of water,
2. The term acidimetry is applied to such operations as those
described above for the determination of the quantities of acids in
solutions,
—=—
QUESTIONS AND EXERCISES.
Calculate the percentage of real acid present in dilute sulphuric acid 30
grammes of which are neutralized by 84 Ce. of the official volumetric soln-
tion of sodium hydroxide. .Ans., 13.628.—Show how much real nitrie acid
is contained in a solution 36 grammes of which are neutralized by $4 Ce.
of normal] solution of sodium hydroxide. Aws., 16.34 percent.
DETERMINATION OF ACID RADICALS PRECIPITATED
BY SILVER NITRATE.
The purity of many salts and the concentrations of their solu-
tions may be determined by this process ; but officially it is chiefly
used for the determination of diluted hydrocyanic acid, other
cyanides, and some bromides and iodides,
STANDARD SOLUTION OF SILVER NITRATE
(Silver Nitrate, AgNO, = 168.69.)
Dissolve 16.869 grammes of pure silver nitrate in one litre of
water. 1000 Ce. of this solution contain 4, of the formula weight in
grammes of silver nitrate. It is therefore a tenth-normal solution.
If pure dry crystals of silver nitrate are not at disposal, and
pure dry crystals of sodium chloride are at hand, a solution
be made of approximate strength and then be standardized by
means of the latter salt. The method may thus be indicated ;—
NaCl + AgNO, = AgCl + NaNO,
=——y —" —_— =
] 0) 58.06 1051 6 8.69
me ane , ore grammes in 1000 Ce,
5. 806 16,869 teuth-normal solution,
DETERMINATION BY SILVER NITRATE, 625
Take rather less than 0,1 gramme of the sodium chloride (NaCl),
and dissolve it in water. The silver chloride (AgCl) precipitated
in the reaction is an insoluble salt, and the end of its precipitation
will serve as a good indication of the completion of the reaction,
A better indicator, however, is a drop of solution of potassium
chromate ; the potassium chromate used must be free from chloride.
The silver nitrate does not act upon the chromate until all the
chloride is converted into silver chloride, after which a deep red
precipitate of silver chromate is produced. This indication is
extremely delicate, and in practice is noticed when the white color
due to silver chloride changes to yellowish from formation of the
first traces of silver chromate, Solutions should be cool und not
very dilute,
Hydroeyanie Acid,—Three to four grammes of diluted acid form
a convenient quantity to operate upon, The HCN is first converted
into KCN or NaCN (by addition of sodium hydroxide). The
following equations explain the reactions :—
2HCN + 2NaOH = 2NaCN + 2H,0
= |— —-
10)53.68 10)97.4
5.568 0,744
2NaCN + AgNO, = NaCN,AgCN + NaNO,
——— ——
10)97.44 10)168.69
0.744 16,869 = grammes in 1000 Ce, tenth-normal solution.
It seems that 5.368 grammes of hydrogen cyanide (HCN) are equiv-
alent to 9.744 grammes of sodium cyanide, and represent 16.869
grammes of silver nitrate, or 1000 Cc, of tenth-normal solution
of silver nitrate,
The sodium cyanide having been obtained, the titration is carried
on until the salt is converted into the double salt (NaCN,AgCN),
immediately after which a permanent turbidity occurs, due to
precipitation of silver cyanide, thus :—
AgCN,NaCN + AgNO, = 2AgCN + NaNO,
The commencement of this turbidity forms a delicate and satis-
factory proof of the completion of the volumetric reaction.
There is, however, a difficulty in the conversion of the acid
into the cyanide (Siebold), to which it is necessary to pay particu-
lar attention, Solution of litmus is added to the acid diluted
largely with water, and the sodium hydroxide solution poured in,
Owing to the strong alkaline reaction of the sodium cyanide formed,
the mixture becomes blue when only asmal! proportion of the acid
has been converted. If then the titration be conducted until the
turbidity appears, only the sodium cyanide will be estimated, leav-
ing free hydrocyanic acid stil] unacted upon. Indeed, sodium cyan-
40
626 VOLUMETRIC ANALYSIS,
ide may be estimated in presence of hydrocyanic acid in this way,
Thus the following reaction (expressed approximately) might occur,
NaUN + 4HCN + AgNO, = AgCN = NaNO, = 4HCN
wee a
Alkaline Turbid and aeid
In this case only one-fifth of the cyanogen originally present
would be precipitated. The mixture would, however, become
acid. If this acidity be prevented, all difficulty is overcome.
The following details (Senier) will be found to answer well. ‘To
the diluted hydrocyanic acid add sodium hydroxide solution until
a strongly alkaline reaction is shown by the solution of litmus,
Then add the silver solution drop by drop from the burette, when
in most cases the mixture will become acid, When it does so,
udd more sodium hydroxide solution, and repeat this provess until
the final reading, when the solution must be alkaline. In this
way the addition of too much sodium hydroxide at the commence-
ment, which would use up silver solution and make the reading
a trifle too high, is avoided,
Diluted Hydrocyanic Acid, U, 5. P., should contain 2 percent,
of hydrogen cyanide (HCN). .
Potassium Cyanide. —A sample, of which 0.1 gramme, im défete
solution, requires 7.3 Ce, of tenth-normal silver nitrate solution,
contains 95 percent, of real cyanide. Any sulphide may be removed
by shaking the solution with lead carbonate. Other ordinary im-
purities do not interfere.
The potassium cyanide of commerce very often contains consid-
erable quantities of sodium cyanide. The cyanide in it is usually
calculated to potassium cyanide, so that as the atomic weight of
sodium is much less than that of potassium it is quite possible for
a sample of ‘ Potassium Cyanide’’ to appear as containing more
than 100 percent, of that salt.
Ammonium Bromide,—Take 0.1 to 0.2 gramme and conduct the
titration in the same manner as for sodium chloride, using potas-
sium chromate as indicator :—
NH,Br + AgNO, = AgBr + NH,NO;
10)97, 29 10)168.69
9,729 16.860 { ~ Fisgmes in mea
Potassium Bromide, —Operate upon rather less than 0.1 gramme,
and conduct the titration in the same manner as with sodium
chloride, using potassium chromate as indicator :—
KBr + AgNO, = AgBr + ENG
10)118, 22 10)166.69
) R99 , ong | grammes in 1000 Oo, of
11,822 16, 869 i tenth-normal solution,
DETERMINATION BY SILVER NITRATE. 627
Remembering that 168.69 parts of silver nitrate (AgNO, =
168.69) decompose 118.22 of potassium bromide (KBr = 118.22),
while on the one hand they decompose as little as 74.04 of potas-
sium chloride (KCl = 74.04), and on the other hand as much as
164.76 parts of potassium iodide (KI = 164.76), it will be seen
that the quantitative operation of the chloride as an impurity may
neutralize the quantitative operation of the iodide, Hence the
necessity to test the bromide qualitatively as well as quantitatively,
and, as regards either impurity singly, of fixing maximum as well
as minimum limits of the action of the volumetric solution of
silver nitrate on potassium bromide. One gramme dissolved in
water, requires for complete precipitation not less than 82 nor
more than 86.1 cubic centimetres of the volumetric solution of
silver nitrate,
Potassium Jodide.—).5 Gm. should require not leas than 50 Ce,
and not more than 80.8 Cc. The salt is often 98 or 99 percent.
pure, containing not more than 0.5 percent. of chloride, with some
sulphate and carbonate,
Sodium Jodide.—0,5 Gm, should require not less than 33 Ce.
nor more than 34.6 Ce,, equivalent to at least 98 percent. of sodium
iodide. |
Potassium Iodide may be determined volumetrically by means
of a twentieth-normal solution of mercuric chloride, the termina-
tion of the operation being indicated by the commencement of the
formation of a red precipitate :-—
(1) 8KI + HgCl, = 2KCl + 2KHgl, (soluble).
(2) 2KHgl, + HgCl, = 2KCl + 8Hgl, (insoluble).
The author of this process, M. Personne, stated in 1875 that
neither chlorides, bromides, nor carbonates interfere, Carles dis-
solves the iodide in alcohol of 174 percent., as much excess of
water may decompose the double iodide. —
Ferrous Iodide. —Messra Naylor and Hooper in 1881 demon-
strated that Personne’s solution is applicable to ferrous iodide,
even in the state of syrup :—
(1) 2Fel, + HgCl, = FeCl, + Fel,, Hgl, (soluble).
(2) Fel,, Hgl, + HgCl, = FeCl, + 2Hgl, (insoluble).
The use of mercuric chloride for determining the strength of
syrup of ferrous iodide was first suggested by FE. Smith in 1859,
The process was improved by T. & H, Smith in 1860,
QUESTIONS AND EXERCISES.
Explain the volumetric method of determining the strength of aqueous
solutions of hydrocyanie acid.—Calenlate how much silver nitrate will
indicate the presence of 1 part of real hydrocyanie acid. Awna., 3.14
parts.
VOLUMETRIC ANALYSIS,
DETERMINATION OF SUBSTANCES READILY
OXIDIZED.
Any substance which quickly unites with a definite weight of
oxygen, or is susceptible of any equivalent action, may be quanti-
tatively tested by ascertaining how much of an oxidi agent
of known power must be added to a given quantity before com-
plete oxidation is effected. The oxidizing agents employed for
this purpose in the Pharmacopeia are iodine, potassium dichro-
mate, and potassium permanganate, Iodine acts indirectly, by
taking hydrogen from water and liberating oxygen; potassium
dichromate directly, by the facility with which it yields three-
sevenths of its oxygen—as indicated by the equations and state-
ments given on pp. 631 and 632; potassium permanganate, by
affording five-eighths of its oxygen in presence of an acid and an
oxidizable substance (p. 683) :—
2KMn0, + 4H,SO, = 2KHSO, + 2MnSO, + 8H,O + 50
STANDARD SoLvuTION OF IODINE.
(Iodine, I = 125.9.)
If pure iodine be not at hand, it may be prepared by mixing
the commercial article with about a fourth of its weight of potas-
sium iodide and subliming. Sublimation may be effected
gently warming the mixture in a beaker, the mouth of which is
closed by a funnel; the iodine vapor ‘condenses on the funnel,
while fixed impurities are left behind, and any chlorine which the
iodine may contain is absorbed by the potassium iodide, an ¢
alent quantity of iodine being liberated. Small quantities may
be similarly treated between two watch-glasses, placed edge to
edge. Any trace of moisture in the resublimed iodine is
by exposure for a few hours under a glass shade placed over a dish
containing concentrated sulphuric acid.
Place 12.59 grammes of pure iodine and about 18 grammes of
pure potassium iodide (an aqueous solution of which is the best
solvent of iodine ; the salt plays no other part in these
in a litre flask, add a tittle water and agitate until thei ‘isdis-
solved ; dilute to 1 litre.
The following substances may be determined by this tenth-nor
mal solution :—
Sulphurous Acid,—Operate on about 0.5 gramme of the acid,
and dilute with water. If the sulphurous acid be diluted to a less
degree than 0.04 or 0.05 pere ent., there will be some risk of the
sulphuric acid subsequently formed heing again reduced oak
phurous acid, with liberation of iodine. In delicate exper .
the distilled water used for dilution should previously be ! ir al
DETERMINATION BY OXIDIZERS. 629
from air by boiling, to prevent the small amount of oxidizing
action which dissolved air would exert. The solution of iodine is
then added until « slight permanent brown tint is produced, show-
ing the presence of free iodine, A better indicator of the termina-
tion of the reaction is starch mucilage, which gives a blue color
with the slightest trace of free iodine,
The following equation shows the reaction that takes place :—
HSO, + HO + I = 2HI + 4H So,
— ——
20)81.47 20)251.8
4.0786 1259 {- panacea
The official sulphurous acid should contain not Jess than 6 per-
cent, of sulphurous anhydride (SO,).
Arsenic.—About 1 gramme of solid arsenous anhydride, aceu-
rately weighed, should be dissolved in the usual quantity of water,
heated to boiling, by aid of 1 gramme of sodium bicarbonate.
The arsenous anhydride is only partly, if at all, converted into
arsenite ; but the reaction with iodine occurs more readily in a
solution which is not acid. When the liquid is quite cold, starch
mucilage is added, and the iodine solution allowed to flow in until,
after well stirring, a permanent blue color is produced.—If 24.6
cubic centimetres of the official solution of Arsenous Acid be used
about 2 grammes of sodium bicarbonate are required. Water is
added, and the titration performed as before. The following
equation exhibits the reaction ;—
AsO, + 10H,O + 41, = SHI + 4H,As0,
80)392. 88 80)1007. 2
4.911 12.59 { ~ Fiath-normal solution.
In the foregoing operation, if ebullition be continued longer
‘than is necessary for the solution of the arsenous anhydride, more
sodium carbonate may be formed than will be reconverted into
bicarbonate by the liberated carbonic acid ; loss of iodine will
then ensue. The results obtained by this method are therefore
liable to vary slightly. E. J. Woolley showed that borax may be
used with advantage in place of the sodium bicarbonate. The
results of latter experiments confirm this conclusion, and show
that determinations can be carried out not only more accurately,
but more conveniently and quickly if borax is used, for it is a
satisfactory solvent for arsenous anhydride and has not the dis-
advantage of being decomposed during the ebullition,
Sodium arsenate may be determined by treating it with sulphur-
ous acid, boiling to expel the excess of the acid and then titrating
with tenth-normal iodine solution as above.
6350 VOLUMETRIC ANALYSIS.
Na, HAsO, + H,SO, = NaAsO, + NaHSO, + H,O
Antimony is also raised in valency under the influence of nas-
cent oxygen, iodine, or an equivalent acid radical, The following
equation illustrates the reaction with tartarated antimony and
iodine. The student should make several determinations with,
say, 20 Cc. of a solution containing 2 grammes of pure tartarated
antimony in 200 Ce. To the 20 Ce, add about an aqual volume
of concentrated solution of sodium bicarbonate and 2 Ce. of starch
mucilage, and then the iodine solution, until, after stirring, the
blue color is fairly persistent. The whole operation should be con-
ducted rapidly or a precipitate of antimonious hydroxide will be
formed, and it is only when in solution that the antimony is
properly attacked, This process is due to Mohr.
(KSbOC,H,O,),, H,0O+ 21, +- 3H,O=4H1+ 2K HC,H,0,+ 2HS8b0,
—$—S ——"
40)659,.80 40)503.6
iea7s 1.09 {~apmesntange
Sodium Thiosulphate.—About 0.4 gramme is a convenient
quantity to employ. It is dissolved in water, starch mucilage
added, and the iodine solution slowly run in, the whole being
frequently stirred, until a permanent blue color is produced. _
In the previous reactions iodine has acted as an indirect oxidiz-
ing agent by uniting with the hydrogen and thus liberating the
oxygen of water. In the present case it unites with an analogue of
hydrogen, namely sodium, a new salt (sodium tetrathionate) being
also produced, thus :—
2(Na,§,0,,5H,0) + I, = 2Nal + NaS0, + 10H,0
SRA 5 ee NS
20)492,92 20)251.8
O4 RAR 49 FQ { =grammes in 1000 Ce, of
24.646 12.59 1 fenth-normal solution.
The U.8. P. requires that the salt contain not less than 98 per-
cent, of sodium thiosulphate,
Note. —Sodium thiosulphate may be obtained in a perfeetly dry
condition by treating the powdered salt with alcohol (90 or 95 per-
cent.), filtering, removing the excess of alcohol by washing with
ether, and then expelling the ether by a current of dry air.
QUESTIONS AND EXERCISES.
Give equations illustrative of the reactions on which the use of a stand-
ard volumetric solution of iodine is based.—From what point of view is
iodine an oxidizing agent ?—What reagent indicates the termination of
the reaction between reducing substances and moist iodine ?—How much
DETERMINATION BY OXIDIZERS. 631
sulphurous anhydride will cause the absorption of 2.518 partsof iodine in
the volumetric reaction? Any,, 0.6358.—What quantity of iodimwe will be
required, under appropriate conditions, to oxidize 5 parts of arsenousanhy-
dride? Ans, 12.805,—Find by calculation the amount of sodium thio-
sulphate, which will react with 13 parts of iodine in volumetric analysis,
Ans,, 25.446,
VoLuMETRiIc SOLUTION OF PoTAssIUM DICHROMATE,
(Potassium Dichromate, K,Cr,O, = 292,28)
When used as an oxidizing agent in acid solution, potassium
dichromate yields the whole of its oxygen to the hydrogen of the
accompanying acid, a corresponding quantity of acid radical being
set free—four-sevenths of this radical immediately combining
with the potassium and chromium of the dichromate, three-sevenths
becoming available for oxidation. Ferrous salts may thus be con-
verted into ferric with sufficient rapidity and exactitude to admit
of the determination of an unknown quantity of iron by a known
quantity of the dichromate,
K.Cr,0,+8H,SO,+6FeSO, =2K HSO, +Cr,(80,),+7H,0+3Fe,(S0,),
The volumetric solution is made by dissolving 4.8713 grammes
(ji of the formula weight in grammes) of potassium dichromate
in water, and diluting to one litre, It is used in determining the
quantity of ferrous iron present in a preparation. It is known
that the whole of the ferrous has been converted to ferric salt
when a small! drop of the liquid placed in contact with a drop of a
fresh and very dilute solution of potassium ferricyanide, on a white
plate, no longer produces a blue color,
If the dichromate employed in making this solution is not known
to be pure and dry, the concentration of the solution may be
checked by dissolving on accurately weighed piece of pianoforte
wire (0,4o0r 0.5 gramme) in dilute sulphuric acid in a small flask,
warming, and then adding the solution of dichromate until con-
version is effected.
The reactions which take place may be thus represented :—
6Fe + 6H,SO, = 6FeSO, + 6H,
—— —,
60)333° 60)905.1
6.56 15,085
6FeSO, +K,Cr,0O,+8H,S80,° 2K H80, +Cr,(S0,\1+7H,0+3Fe,(S0,),
—,_— —_——
GO )905.1 H0)202.28 —
15.085 4.8713 — grammes in 1000 Ce, of tenth-normal solution.
632 VOLUMETRIC ANALYSIS,
It is evident that 5.55 grammes of iron are equivalent in the
reactions to 4.8713 grammes of dichromate (i,¢., to 1000 Ce. of
the standard solution), Now supposing that 0.5 gramme of piano-
forte wire has been employed, and the quantity of solution of
dichromate of unknown strength used has been 88 Ce, ; how many
Ce. of this solution contain 4.8713 grammes of dichromate, that
is, how many Ce, will be required to oxidize ferrous salt contain-
ing 5.55 grammes of iron? By calculation it is found that 978.5
Cc. contain 4.8713 grammes of dichromate, and are equivalent to
1000 Ce. of standard solution. It might be employed without
being diluted or, better, be diluted to official standard (tenth-nor-
mal) strength,
For standardizing the solution of dichromate, instead of iron
wire, the light-green crystals of the double ammonium ferrous sul-
phate (NH,),80,, FeSO,,6H,O = 389.44) may be used, for it is a
very stable salt,
Special care should be taken in all these determinations of sub-
stances readily oxidized to avoid atmospheric oxidation. Flasks
may be loosely corked, or corked closely with n gas exit-tube
ing just beneath the surface of a Jittle mercury or sodas eens
ate solution, and in all cases the titration should be perfoi
quickly. When standardizing with iron wire, any slight oxidation
may be remedied by addition of a fragment of zine, the last por-
tions of which must be removed or dissolved before the titration
is commenced,
The ferrous salt in the following substances may be determined
by this solution.
Ferroua sulphate.—Use | to 2 grammes, Dissolve the sulphate
in water and add excess of sulphuric acid ; the preceding equation
indicates the reaction,
Saccharated Ferrous Carbonate.—Dissolve 1 to 2 grammes in
excess of dilute sulphuric or hydrochloric acid. Sulphuric acid
is preferable because ferrous sulphate absorbs oxygen much less
readily than ferrous chloride. The reaction that takes place with
dichromate is shown in the following equation :—
6FeCO, + 14H,SO, + K,Cr,0, =
60)690.3 60)202, 28.
11.505 4.8713 {“ftnuvnormal solution,
2KHSO, + Cr(SO.), + 4Fe(80,), + I18H,O + 6CO,
The U.S. P. requires not less than 15 percent. of ferrous ear-
bonate. Commercial samples yield from 20 to 80, and sometimes
35 percent., according to the care with which oxidation has been
prevented. The theoretical percentage obtainable from the in-
gredients is 45.5, the quantity that would be present if the com-
DETERMINATION BY OXIDIZERS, 633
pounds were anhydrous and unoxidized—conditions never obtained
in practice, Phosphoric acid should be used to dissolve the sac-
charated ferrous carbonate, the reason for this being that dilute
hydrochlorie or sulphuric acid converts ordinary sugar into inverted
sugar, Which is easily attacked by chromic acid.
Magnetic Iron Oxide,—Use about the same quantity as of arsen-
ate or phosphate, and proceed in the same manner. The reaction
may thus be shown —
6Fe,0, + 382H,SO, + K,Cr,O, =
— a ————
60)1380, 12 60)292,28
sue 4.8718} ~ Fam ne it
2KHSO, + Cr(SO), + 9Fe(SO), + 31H,O
Absolutely pure magnetic oxide of iron contains 31 percent. of
ferrous oxide, Oxidation occurs, however, during manufacture,
as in the case of the ferrous salts just described,
Note.—The use in quantitative analysis of this volumetric solu-
tion of potassium dichromate admits of great extension. The stu-
dent should at least employ it in the case of a few iron ores.
VOLUMETRIC SOLUTION OF POTASSIUM PERMANGANATE,
(Potassium Permanganate, KMnO,= 156.98. )
Dissolve 8.3 grammes of potassium permanganate in water and
dilute to one litre. The solution is then standardized by means
of a weighed quantity of pianoforte wire or of ammonium ferrous
sulphate as described under potassium dichromate,
10Fe + 10HSO, = 10FeSO, + 10H,
—— ——
100)555 100)1508.5
5.56 15,085
10FeSO, -++ 2KMnO, + 9HS0, =
— ——" a
100)1508.5 100)813,96
15.085 3.1396 = grammes in 1000 Ce. of standard solntion,
2KHSO, + 2MnSO, + 8H,O + 5Fe(80),
This solution may be used in nearly all cases for which the
volumetric solution of potassium dichromate has been recom-
mended, It must not be used in presence of hydrochloric acid,
as this acid is itself attacked by permanganate with production of
water and chlorine.
634 VOLUMETRIC ANALYSIS,
*
Oxalic acid and other oxalates may be determined by means of
this standard solution of permanganate. About 0.2 gramme of
crystallized oxalic acid or about 0.25 gramme of ANIMONLUM Oxa-
late, (NH,),C,O,, H,O, may be dissolved in water, a small quantity
of dilute sulphuric ‘acid added, the solution warmed to about 60°
C,, and the volumetric solution of permanganate run in from 4
burette until a slight but permanent pink coloration, due to excess
of permanganate, is produced,
5(H,C,0,.2H,O) + 2KMn0O, + 4HS80, =
—— SS —o
100)625, 50 100)3138. 96
6,255 3. 196 = grammes in 1000 Ce, standard sol,
2KH80, + 2MnSO, + 18H,O + 1000,
It is obvious that pure crystallized oxalic acid may be used as
a means of standardizing the potassium permanganate solution.
QUESTIONS AND EXERCISES.
Write equations explanatory of the oxidizing action of potassium di-
chromate.—One hundred Ce. of an aqueous solution of potassium dichro-
mate contain gh, of the formula weight of the salt in grammes; with what
weight of metallic iron, dissolved in hydrochloric acid, will this volume
react? Ans., 0.556 grammes.—If 3 gramwes of impure crystallized ferrous
sulphate dissolved in acidulated water, require 93 Ce. of the standard solu-
tion of dichromate for complete conversion into ferric salt, what percent-
age of ferrous sulphate is present? <Ans., §85.6.—How much potassinm
dichromate is required for the conversion of 10 parts of crystallized ferrous
sulphate into ferric salt? Ans., 1.763.—Show what quantity of pure
ferrous carbonate is indicated by 1.475 parts of dichromate as applied in
volumetric am alysis. Ana., 3. 48. —What quantity of official saccharated
ferrous carbonate is equivalent: to 0.7375 partof dichromate in the volu-
metric reaction? Angs., 5.2.
" REDUCED.
Any substance which quickly yields a definite quantity of oxy-
gen may be quantitatively te sted by ascertaining how much of a
reducing agent of knowt n powe er must be added toa given quantity
before comple te reduction iseffected. The chief compounds whieh
may be used for this absorption of oxygen (deoxidizers or reducing-
agents, as they are commonly termed) are sodium thiosulphate,
sulphurous acid, oxalic acid, arsenous acid. The first-named is
officially used in the determination of free iodine, and, indirectly,
of chlorine and chlorinated compounds, chromates and ferrie salts,
DETERMINATION OF OXIDIZERS, 635
Iodine and chlorine are regarded as oxidizing agents, because
their great affinity for hydrogen enables them to become powerful
indirect oxidizers in presence of water.
STANDARD SOLUTION OF SopiuM THIOSULPHATE,
(Sodium Thiosulphate crystallized, Na,S,O0,,5H,O = 246.46.)
Dissolve 80 grammes of sodium thiosulphate in a litre or less
of water, Fill a burette with this solution, and allow it to flow
into a beaker containing, say, 15 Ce. of the volumetric solution
of iodine until the brown color of the iodine is just discharged—
or, starch being added, until the blue starch iodide is decolorized,
(T ‘he latter affords the more delicate indication.) When iodine
and sodium thiosulphate react, two atoms of iodine remove two
of sodium from two molecules of the sodium thiosulphate, sodium
tetrathionate being formed, thus :—
I, +o 2(Na,8,0,,5H,O) = 2Nal + Na,8,0,+ 10H,O
en ————
20)251.8 20)492. 92
12.59 = pee ates 24.646 =grammes of thiosulphate in 1000 Ce,
Now suppose the number of Ce, required to completely react
with the 15 Ce, of standard iodine were 14 Ce., how many Ce, of
this thiosulphate solution would be equivalent to 1000 Ce. of the
volumetric solution of iodine? In other words, how many Ce.
contain 24,646 grammes of thiosulphate? 983 Ce. of the solution
of sodium thiosulphate under examination contain 24.646
grammes of the salt, and are equivalent to 1000 Ce, of the official
volumetric solution, The 938 Ce, ean be diluted to 1000 Ce. or
used without dilution. In either case its concentration would, as
usual, be recorded on the label. The following substances may
be determined by means of sodium thiosulphate solution of known
concentration,
A solution of sodium thiosulphate containing 24.646 grammes
of sodium thiosulphate per litre is-described as a tenth-normal
solution, as each Ce, is equivalent to 1 Cc. of the tenth-normal
solution of iodine.
Solution of Chlorine.—About 10 grammes may be taken, Excess
of potassium iodide is added—that is, to 10 grammes of solution
of chlorine, about half a gramme of iodide. A quantity of iodine
is set free by the chlorine exactly in the proportion to their atomic
weights. The titration is then conducted as already described,
The following equations show the reactions :—
Cc, + #1 = 1, + 2KOl
20)70.36. 20)251.8
5.518 12,59
636 VOLUMETRIC ANALYSIS.
Fa + S08 5,0558,0) |= SNaLy i RA
$$, $$
20)251,8 20)492.92
12.59 94.646 = grammes in 1000 Ce. of tenth-normal solution.
It is evident, then, that 1000 Cc, of tenth-normal solution of
sodium thiosul phate, or 4 corresponding quantity of a solution of
different concentration, is equivalent to 3.518 grammes of
Jodine.—Solid iodine is dissolved in solution of potassium iodide,
and titrated as already described. About 0.2 gramme is a conve-
nient quantity to employ. 1000 Ce. of tenth-normal thiosulphate
solution is equivalent, as seen in the equation, to 12.59 of iodine.
It is assumed in this operation that the iodine has been shown by
qualitative analysis to be free from chlorine and bromine ; for these
elements resemble iodine in reacting with sodium thiosulphate,
hence would reckon as iodine in a yolumetric assay, The official
iodine (Jodum, U. 8. P.), should contain not less than 99 percent.
of pure iodine,
Chiorinated Lime.—Operate on from 0,1 to 0.2 gramme. Dis-
solve in water, and add excess of potassium iodide and dilute hydro-
chlorie acid. 0.1 to 0.2 gramme of chlorinated lime requires 0.4
to 0.8 gramme of potassium iodide. The following equations show
the reactions: —
CaOCl + 2HCl = CaCl, + HO + Gh;
or, CaOCl, + HO, = CaSO, + H,O + Cl
The chlorine thus set free liberates an equivalent amount of
iodine, and this is titrated as before. (See the equations for the
solution of chlorine, pp. 635, 636.) This chlorine, liberated from
chlorinated lime by ‘acids, is its available chlorine for indirect oxi-
dizing action. It should correspond (U. 8, P.) to not less than
30 percent,
Solution of Chlorinated Lime. —About 2 grammes is a convenient
quantity to use. 1 gramme of potassium iodide and excess of acid
should be added, and the available chlorine determined as in the
case of the solid.
Solution of Chlorinated Soda.—About 2 grammes are mixed with
the usual quantity of water, and 1 gramme of potassium lodide
and excess of acid added. The available chlorine is determined
as in the case of chlorinated lime. The reaction by which the
chlorine is evolved is familiar :—
NaC] NaOCl + 2HCl = 2NaCl 4+ H,O + Cl,
The action of the liberated chlorine on the potassium iodide and
the iodine on the thiosulphate solution has been described under
‘solution of chlorine."’ The official (U. 8. P.) requirement is at
least 2.4 percent., by weight, of available chlorine,
DETERMINATION BY OXIDIZERS. 637
Sodium thiosulphate may also be used for the determination of
iron in ferric compounds. This method is based on the fact that
when ferric chloride is digested with potassium iodide, it is re-
duced to ferrous chloride, Some of the potassium iodide is decom-
posed by the chlorine thus released, and an equivalent quantity
of iodine is liberated. The ferric salt should be dissolved in
hydrochloric acid, the solution nearly neutralized with sodium
hydroxide solution, transferred to a well-stoppered flask, and ex-
cess of a concentrated solution of potassium iodide added. The
flask should then be closely stoppered and heated to 50° or 60° C,
on a water-bath for about 20 minutes ; iodine is liberated, and
dissolves in the excess of potassium iodide. After cooling the
solution and adding mucilage of starch, the thiosulphate solution
is run in until the blue color disappears. The following equations
show the reactions :—
2FeCl, + 2KI = 2FeCl, + 2KCI + I,
—-—"
20)322. 08
16.104
I, + 2(Na,S,0,5H,O) = 2Nal + NaS,O, + 10H,0
—$——_ -$ +
20)494. 92
24,746—grammes in 1000 Ce. of tenth-normal solution.
Thus it is evident that 1000 Ce, of tenth-normal solution of
sodium thiosulphate are equivalent to 16,104 grammes of ferric
chloride, The following official compounds may be examined by
this method :—Ferri Chloridum, Ferri Citras, Ferri et Ammonii
Citras, Ferri et Ammonii Sulphas, Ferri et Ammonii Tartras,
Ferri et Potassii Tartras, Ferri et Quinine Citras, Ferri et Quin-
ins Citras Solubilis, Ferri et Strychnine Citras, Ferri Phosphas
Solubilis, Ferri Pyrophosphas Solubilis, Ferrum Reductum,
Liquor Ferri Chloridi, Liquor Ferri Subsulphatis, Liquor Ferri
Tersulphatis, and Tinctura Ferri Chloridi.
QUESTIONS AND EXERCISES,
For what purpose is the volametric solution of sodium thiosulphate
used ?—On what reaction is based the quantitative employment of sodium
thiosulphute Y—How much sodium thiosnIphate is required to show the
presence of 10 parts of iodine? Ans., 19.574.—Calculate the quantity of
chlorine 4.96 parts of sodium thiosulphate are equivalent to in volumetric
analysis, Ans, 0.708,—Describe the operations involved in the determi-
nation of the strength of bleaching-powders.—W hat indicator is used to
show the termination of the reaction between iodine and sodium thio-
sulphate ?
>
638 GRAVIMETRIC ANALYSIS.
QUESTIONS, WITH ANSWERS FOR VERIFICATION.
Calculate how much potassium bicarbonate is contained in an eight-
ounce bottle of medicine, seven fluid drachms of which are phytic aye
by 2.72 grainsof pure sulphuric acid, Ans, 36.3 A sample of
soda-ash is said to coutain 78 percent. of pure pei, cae soditim carbor-
ate: if the statement be true, how much of the official volumetric solu-
tion of sulphuric acid will neutralize 5 grammes of the specimen? Ans,
74 Ce.—2.69 grammes of commercial sulphuric acid are neut
43.5 Ce. of the official volumetric solution of sodium hydroxide; how
much acid of 96.8 percent. is present? Aus, The 2.69 contain 2 05,.—Four
Ce. of a litre and a half of concentrated hydrocyanic acid are equivalent
to 89 Ce. of the official volumetric solution of silver nitrate; to what
volume must the bulk of the acid be diluted for the prodoction of acid
of pharmacopaial strength? Ans., 8.894 litres. —How much pure metal
is present in a sample of iron 1 gramme of which, dissolved in dilute sul-
phuriec acid, is exactly attacked by 95.7 Cc. of a volumetric solution of
ra eH dichromate which is 0.6 percent. stronger than the
solution ?
GRAVIMETRIC ANALYSIS.
(For preliminary remarks on the general principles of gravimetrie
analysis and the relation of gravimetric and volumetric analysis to
each other, ace pages 609 and 610.)
DETERMINATION OF METALLIC RADICALS.
POTASSIUM.
Outline of the Process. —This element is usually determined in
the form of potassium chloroplatinate. Qualitative analysis hay-
ing proved the presence of potassium and other radicals in a sub-
stance, a small quantity of the material is accurataly weighed,
iuatioaet and the other metallic radicals removed by appropriate
means; the precipitates are well washed, in order that no trace of
the potassium salt be lost, the resulting liquid concentrated over
a water-bath (to avoid Joss that would occur mechanically duri
ebullition), hydrochloric acid added if necessary, solution
chloroplatinic acid poured in, and evaporation continued to dry-
ness : excess of the precipitant is then dissolved out by adding, to
the dried residue, alcohol (90 percent.) mixed with half its bulk
of ether (a mixture in which the chloroplatinate is insoluble), the
whole carefully poured on to a tared and dried filter, washed with
the mixture of aleohol and ether till every trace of chloroplatinic
acid is removed, and dried and weighed; from the weight of
potassium chloroplatinate the proportion of potassium, or equiva-
lent in quantity of a salt of potassium, is ascertained by calculation.
Note. —From this short description it will be seen, first, that
the chemistry of quantitative analysis is the same as that of quali-
DETERMINATION OF POTASSIUM. 639
tative; and secondly, that the principle of gravimetric is the same
as that of volumetric quantitative analysis:—the combining pro-
portions of substances being known, unknown quantities of ele-
ments may be ascertained by calculation from known quantities
of their compounds,
Apparatus.—In addition to the very delicate balance, accu-
rate weights and the common utensils, a few special instruments
are used in quantitative manipulation ; some of these may be
prepared before proceeding with the determination of potas-
sium.
Filter-paper may be of the kind known as “Swedish,” the
texture of which is of the requisite degree of closeness, and
its ash small in amount, A large number of circular pieces
of one size, six to eight centimetres in diameter, should be cut
ready for use. In delicate experiments, where a precipitate
on a filter has to be ignited and the paper subsequently burnt,
the weight of the ash of the filter must be deducted from the
weight of the residue. The ash is determined by burning
ten or twenty of the cut filters. These are folded into small
compass, a piece of platinum wire twisted a few times round
the packet so as to form a cage, the whole held by the free
end of the wire over a weighed porcelain crucible placed on
the centre of a sheet of glazed paper, and the bundle ignited
by a spirit-lamp or Bunsen flame. The flame is allowed to
impinge against the charred mass until it falls into the crucible
below, any stray fragments on the sheet being carefully brushed
into the crucible, the latter placed over a flame until carbon has
all been burnt off, and nothing but ash remains; the whole
cooled, weighed, and the weight of the crucible deducted.
The weight of the residue divided by the number of pieces
used gives the average weight of ash in each filter.
The necessity for carrying out the operations described in
the preceding paragraph has been almost entirely obviated by
the introduction of the so-ca)led ashless filters—circular filter
papers of various sizes, from which the mineral matter which
gives rise to the ash has been removed, practically completely,
by extraction with hydrochloric and hydrofluoric acids.
For the complete retention of certain exceeding finely di-
vided precipitates, such as barium sulphate, calcium oxalate,
cuprous thiocyanate, etc., filter papers possessing the closest
texture must be employed,
A pair of weighing tubes (Fig. 72), for holding dried filters,
O40 GRAVIMETRIC ANALYSIS.
may be made from two test-tubes, one fitting closely within
the other. About five centimetres of the closed end of the
outer and seyen of the inner are cut off by leading a erack
round the tube with a pencil of incandescent charcoal, and the
sharp edges fused in the blow-pipe flame. A filter, after dry-
Fic. 72. Fra. 73.
A pair of weighing-tubes. Clamped watcb-glasses for weighing-
ing, is quickly folded and placed in the narrower tube, the
mouth of which is then closed by the wider tube. This pre-
vents reabsorption of moisture from the air, A pair of wateh-
glasses, having accurately ground edges and clamped as shown
in Fig. 73, forms a convenient arrangement for weighing
filters, etc. Small weighing bottles, light stoppered bottles
having wide mouths, are also useful.
The wash-bottle (Fig. 74), holding the aleohol and ether, is
a common flask, through the cork of which a short straight
tube passes. The outer end of the tube should be sufficiently
' narrowed to enable it to deliver a very fine
Fic. 74. stream of the liquid. The flask being inverted,
the warmth of the hand expands the air and
vapor to a sufficient extent to force out the
liquid,
The ordinary wash-bottle for quantitative opera-
tions should be formed of a flask in which
water may be boiled, fitted up as usual (see p.
116).
A water-oven is the best form of drying-apparatus. Tt is a
small square copper vessel, jacketed on five sides and having a
door on the sixth; water is poured into the space beteresal aial
inner and outer casing, and the whole placed over a gas-lamp or
other source of heat, moist air and steam escaping by appropriate
apertures. Holes in the top an inch or two in diameter, covered
when not in use, serve for the reception of small dishes contain-
ing liquids to be evaporated. Drying at higher temperatures than
the boiling-point of water may be practised by using oil or paraf
fin instead of water, inserting a thermometer in the oil: or b
the use of an air-bath, which is simply a metal box provided with
a door and heated by means of a Bunsen flame.
A desiceator is a glass vessel in which a substance to be dried,
DETERMINATION OF POTASSIUM, 641
or to be cooled in a dry atmosphere, is enclosed along with a
powerful dehydrating agent such as concentrated sulphuric acid,
potassium hydroxide, or fused calcium chloride (Figs. 75 and 76).
Pure distilled water must be used in all quantitative determina-
tions. :
Note,—In practising the operations of quantitative analysis,
experiments should at first be conducted on definite salts of known
composition, for the accuracy of results may then be tested by
calculation.
Fro. 75. Fig. 76.
Desiccator, Desiccator.
Determination of Potassium in the form of Potassium Chloro-
platinate-—Select two or three crystals of pure potassium
nitrate, powder them in a clean mortar, dry the powder by
gently heating in a porcelain crucible over a flame for a few
seconds, place about a couple of decigrammes (0.2 grm.) of
the powder in a counterpoised watch-glass, acurately weigh
the selected quantity, transfer to a small dish, letting water
from a wash-bottle flow over the watch-glass and run into the
dish, warm the dish until the nitrate is dissolved, acidulate
with hydrochloric acid, add excess of aqueous solution of
chloroplatinic acid (a quantity of solution containing about
0.5 grm. of H,PtCl,), evaporate to dryness on a water-bath.
While evaporation is going on, place a filter and the weighing-
tubes in the water-oven, exposing them to a temperature of
100°C. for about half an hour; fold the filter and insert it in
the tubes, place them in a desiccator to cool, and when cold
accurately note their weight. Arrange the weighed filter in
a funnel over a heaker, Transfer the dried and cooled
chloroplatinate from the dish to the filter by moistening the
the residue with the mixture of aleohol and ether and, when
the salt is loosened, pouring the contents of the dish into the
4l
642 GRAVIMETRIC ANALYSIS.
paper cone. Any salt still adhering may he freed by the
finger, which, together with the dish, should be washed in the
stream of alcohol and ether, the riusings at once flowing
into the filter. The filtrate should have a yellowish-brown
color, due to the excess of chloroplatinic acid. If it is color-
less, an insufficient amount of the precipitant has been added,
and the whole operation must be repeated. After washing
with the mixture of alcohol and ether until the liquid is no
longer colored by chloroplatinic acid, the precipitate and filter
are dried in the water-oven, folded and placed in the weighing-
tubes, the tubes placed open in the drying-oyen for a short
time, removed, closed, allowed to cool and then weighed.
The drying and weighing when cold should be repeated until
the whole ceases to alter, the final weight being noted.
Analytical memoranda may have the following form ;—
Watch-glass and substance . , tae
Watch-glass,... .. 0%, 9 Se eer
Substance .
Weighing-tubes, filter, and salt .. .
Weighing-tubes and filter. .
K,PtCl,
The calculation are simple :
As vie is equivalent to eerh j?
. the weight of
so « chloroplatinate f is equivalent to x.
obtained
x will be the weight of pure potassium nitrate in the quantity
of substance operated on. x should in the present instance be
identical with the weight of substance taken, because, for
educational purposes, the pure nitrate is under examination.
Only after analyses of pure substances have yielded the
operator results practically identical with those obtained by
calculation, can analyses of substances of unknown degree of
purity be undertaken with confidence, A table of atomic
weights, from which to find molecular weights, is given in the
Appendix.
Platinum Residues should be preserved, and the metal recovered
from time to time (see p. 201),
DETERMINATION OF SODIUM. 643
Hot alcohol sometimes reduces chloroplatinic acid, the metal
being thrown out of solution in a finely divided form, known as
platinum black ; only aqueous solutions, therefore, of this reagent
should be used where heat is employed. Hence, also, in washing
out excess of chloroplatinic acid with the mixture of alcohol and
ether the application of heat should be avoided.
Proportional Weights of Equivalent Quantities of Potassium and
some of its Compounds,
Bickel sii ice sis eo gee eos 0 el se ead
Oxide .. K.O PF <a un ee SS
Hydroxide (Caustic Potash) 2KOH ... . . . 111.48
Carbonate (anhydrous) . . K,CO, ep eretae 137,27
Bicarbonate... . .. .2KHCO,.. . . . 198.82
Nitrates 4 Sr LAG Pee er 2KNO, .... . - 200.86
Chloroplatinate . +. . .K,PtCl.. .. . . 4821
SODIUM.
Sodium is usually determined as sulphate. Accurately
weigh a porcelain crucible and lid, place within it about 0.3
of pure powdered rock-salt, and again weigh, making « mem-
orandum of the weights in a note-book. Add rather more
concentrated sulphuric acid than may be considered sufficient
to convert the chloride into acid sodium sulphate. Heat the
crucible gradually, the flame being first directed against the
side of the crucible to avoid violent ebullition, until fumes of
acid are no longer evolved, toward the end of the operation
dropping in one or two fragments of ammonium carbonate to
facilitate complete expulsion of all excess of acid. When
cold, weigh the crucible and contents. The weight of the
crucible having been deducted, the amount of sulphate
obtained should be the exact equivalent of the quantity of
sodium chloride taken.
2NaCl + H,SO, = NasO, + 2HCI
ye —,
116,12 141,11
O44 GRAVIMETRIC ANALYSIS,
Proportional Weights of Equivalent Quantities of Sodium and
some Sodium Compounda.
Metal. 5. +o 4) a 2 Des © Gr eee
Oxide... . - Na,O or) aly si te:
Hydroxide (O austic Soda) 2 NaOH .= a = a syle meene
Carbonate (anhydrous) . Na,CO, . . » » 105.31
Carbonate (crystals) - Na,CO,, 10H 0 .» . S841
Bicarbonate . . « . ZN aHCO, 0 » a SORE
Chloride... > « SACL. a eee
Sulphate (anhydrous) | . » NSO, Ssh . dla
Sulphate (crystal) . . Na, ‘SO, LOH 0, . . s19.91
AMMONIUM.
Salts of ammonium are, for purposes of quantitative anal-
ysis, generally converted into the chloroplatinate (NH,),PtCl,
the details of manipulation being the same as those observed
in the case of potassium (p.641). About 0.15 gramme of
pure, white, dry, ammonium chloride may be taken for experi-
ment.
Composition of the Chloroplatinate.
In formula wt. Tn 10 parts.
193.3 » «s » 19880, . . 407908
35,18 -«. S108... ae
3.95 M2... 27.86... 6828
A Wake Ot. a ee 6.00 ... ») Ise
440,24 100.000
The proportion of nitrogen, or ammonium, in the ehlore-
platinate may also be ascertained from the weight of plati-
num left on ignition ; indeed, this operation must he performed
if methyl-ammonium or any other substituted ammonium be
present. The heat must be ap yplied slowly, or platinum will
be mechanically carried off with the gaseous products of
decomposition.
Proportional Weights of Equivalent Quantities,
Ammonia ..
Ammonium Sy ieee
Ammonium « e hloris de
7 i rt ®
( ‘hlorop latin: ate ere ts _ (NH) Pee 1,
‘‘Ammonium carbonate’? . (N, H, Cc oO j+3
Ammonium sulphate . (NE, ),80,
33.86
. 65,86
. 106,22
. 440.24
82. 104.006
. 181.21
DETERMINATION OF BARIUM. 645
Barium is determined in the form of anhydrous barium
sulphate ( BaSO,).
Process.— Dissolve 0.5 or 0.40f pure crystallized and dried
barium chloride or nitrate in about 100-150 Ce. of water in a
beaker, heating to incipient ebullition, and slightly acidulating
with hydrochloric or nitrie acid, Heat some dilute sulphurie acid
(prepared some days previously, so that any lead sulphate may
have deposited) and add the hot acid to the barium solution
in successive small quantities so long as a precipitate forms,
keep the mixture hot for sometime, set aside for half an
hour, pass the supernatant liquid through a filter, gently
boil the residue twice or thrice with acidulated water ; finally
collect the precipitate on the filter, removing adherent parti-
cles from the beak by the finger, and cleansing by a stream of
hot water from the wash-bottle. The precipitate must be
washed with hot water until the filtrate no longer turns litmus-
paper red or gives any cloudiness when tested with barium
chloride. The filter with the barium sulphate, having been
thoroughly drained, is dried in a warm place, usually by sup-
porting the funnel in an inverted bottomless beaker over a
sand-bath or hot plate.
The barium sulphate is now removed from the filter, heated
to drive off every trace of moisture, and weighed, This is
accomplished by placing a weighed porcelain crucible on a
sheet of glazed paper, holding the filter over it, and carefully
transferring the precipitate. The sides of the filter are then
gently rubbed together and the detached powder dropped into
the crucible, the paper folded, encased in two or three coils of
one end of a platinum wire, and burnt over the crucible, the
ash and any particles on the sheet of paper dropped into the
barium sulphate, the open crucible exposed over a flame until
its contents are quite white, covered, cooled, and weighed.
Note.—If the filter has not been freed by thorough washing
from all traces of acid the paper will be brittle when dry,
falling to pieces on being folded.
Formula
. “ Formule Weights,
Barium chloride... . . BaCl,2H,O . . . 242,62
Barium nitrate ... . Ba(NO,), . . ~ . 269,54
Barium sulphate .... BaSO,. . .. . . 281.75
GRAVIMETRIC ANALYSIS,
Composition of Barium Sulphate,
In formula weight.
. 186.40 . .
. « 136.40
31.83 nae SBS
15.88 eK 4... 66,42
In the first four or five educational experiments it is not
essential to take filter-ash into account, Mistakes of manipu-
lation due to inexperience may cause far greater errors,
CALCIUM.
Calcium is usually precipitated as oxalate, the precipitate
ignited, and the resulting carbonate weighed.
Process.— Dissolve 0.3 or 0.4 of dried colorless erystals of
eale-spar in about a third of a litre of water acidulated with
hydrochlorie acid, heat the solution to near the boiling point,
add excess of boiling solution of ammonium oxalate, then
ammonia until, after stirring, the liquid smells strongly of
ammonia ; set aside in a warm place for twelve hours. Gare-
fully pour off the supernatant liquid, passing it rea a
filter; add hot water to the precipitate, set aside for half an
hour, again decant, and, after once more washing, transfer the
precipitate to the filter, allowing all contained fluid to pass
through before a fresh portion is added. Wash the precipi-
tate with hot water, avoiding a rapid stream, or the precipi- |
tate may be driven through the pores of the paper. re
transfer to a weighed crucible, and incinerate, as deseribed for
barium sulphate, and slowly heat the precipitate until the
bottom of the crucible is just visibly red when seen in the —
dark, As soon as the residue is white or only faintly gray,
remove the flame, cool, and weigh. |
The resulting calcium carbonate should have the sam
weight as the cale-spar from which it was obtained. Tf Joss —
has occurred, carbonic anhydride has probably escaped. Tp
that case moisten the residue with water, and after a few
minutes test the liquid with red litmus or turmeric paper ; if |
analkaline reaction is noticed, it is due to the presence of —
caustic lime. Add a smal! lump of ammonium carbonate, —
evaporate to dryness on a water-bath, and again ignite, ¢ is
" DETERMINATION OF MAGNESIUM, 647
time being careful not to go beyond the prescribed tempera-
ture. The treatment may, if necessary, be repeated.
Proportional Weights of Equivalent Quantities of Calcium and
some of its Compounila,
Metal 51 wise tr, tee ind eee .. 89.8
Oxide (quicklime) .....,€aO ...... 65.68
Hydroxide (slaked lime) .. .Ca(OH),. . .. . 73.56
Oarbonate’ «ss wie as SOMO NS « a) aes 99,35
Sulphate (anhydrous) .....CaSO,; ..... 135.15
Sulphate (crystalline or precipi-
ee) ee eS Ae aS0,2H,O . . . 170.91
Chioride” sss ome evs MaDe a one OIE
Phosphate (of bones) . . - . . Ca,(PO,),+3. . . 102.66
MAGNESIUM.
Process 1.—The magnesium carbonate of pharmacy may be
examined by heating a weighed quantity to redness in a
porcelain crucible. If it has the composition indieated hy the
formula given in the Pharmacopeia, 4MgCO,, Mg(OH),,
5H,O, it will yield 40 percent. of magnesia (MgO).
Process 2.—T'he general form in which magnesium ia pre-
cipitated is un ammonium magnesium phosphate (NH MgPO,,
6H,O); this by heat is converted into magnesium pyrophos-
phate (Mg,P,O,). Accurately weigh a smal] quantity (0.4 to
0.5 gramme) of pure dry magnesium sulphate, dissolve it in
two to three hundred cubic centimetres of cold water in a
beaker, add ammonium chloride, ammonia, and sodium or am-
monium phosphate, agitate with a glass rod (without touching
the sides of the vessel, or o> fagens will firmly adhere to the
rubbed portions), and set aside for twelve hours. Collect the
precipitate on a filter, wash with water containing a tenth of
its volume of the strongest solution of ammonia, until the filtrate
no longer gives a precipitate with a solution of silver nitrate
acidulated with nitric acid. Dry, transfer to a porcelain
crucible, burn the filter in the usual way, heat slowly to
redness, cool, and weigh.
Proportional Weights of Equivalent Quantities of some
Magnesium Compounds,
Pyrophosphate . . - Mg.P,O, . 2. «6 1 1 eos 1s oo ookeOG
Sulphate ... . .2(MgSO,7H,O) ..... .. - 489.88
Oxide. .4 10.4% GBR Ge ee 2 ee eee
Official carbonate . . 4MgCO,,Mg(OH),,5H,O +2. , . 241,13
GRAVIMETRIC ANALYSIS.
ZINC.
Zinc is usually determined as oxide (ZnO), occasionally as
sulphide (ZnS).
Process.— Dissolve a weighed quantity (0.5 to 0.6 gramme)
of zine sulphate in about half a litre of water in a beaker,
heat to near the boiling-point, add solution of sodium carbon-
ate in slight excess, boil, set aside for a short time; pass the
supernatant liquid through a filter, gently boil the precipitate
with more water, again decant ; repeat these operations two or
three times; collect the precipitate on the filter, wash, dry,
transfer to a crucible, incinerate, ignite, cool, and weigh.
285.41 (=the formula weight) of sulphate should yield
80.78 (=the formula weight) of oxide.
MANGANESE.
To ascertain its value for evolving chlorine from hydro-
chloric acid, a weighed quantity of finely powdered black
Fig. 77.
manganese oxide is heated in a small flask with pure hydro-
chloric acid (contained in an inner tube as for “oxalates”
and “carbonates,” p. 665), and the resulting chlorine conveyed
into a U tube containing solution of potassium iodide, (See
Fig. 77.) The amount of iodine thus liberated is determined
by means of the volumetric solution of sodium thiosulphate,
125.9 parts of iodine indicate 35.18 of chlorine.
Black manganese oxide may also be estimated by the reac-
tion and apparatus described under “‘Oxalates,”’ p, 666.
DETERMINATION OF ALUMINIUM. 649
Aluminium is always precipitated as hydroxide, Al(OH),
and weighed as oxide (A1,O,).
Process.—Dissolve about 2 grammes of pure dry ammo-
nium-alum in half a litre of water, heat the solution, add am-
monium chloride and a slight excess of ammonia, boil gently
until the odor of ammonia has nearly disappeared, set aside for
the hydroxide to deposit, pass the supernatant liquid through
a filter, wash the precipitate three or four times by decanta-
tion, transfer to the filter, finish the washing, dry, burn the
filter, ignite in a covered crucible, cool, and weigh.
AIK(G0;).+ TSE ee Fe pe
AINH(SO,),+12H,O ......,... . . 450,09
ALO). ck.3! Sn aa es . 101,44
Percent. of Al,O, yielded by ammonium-alum . 11.27
QUESTIONS AND EXERCISES,
Give details of the manipulations observed in gravimetrically deter-
mining potassium or ammonium.—What quantity of sodium chloride is
contained in a sample of rock-salt 0.351 gramme of which yields 0.426 of
sodium sulphate? Ans, 90.83 percent.—To what weight of ammonium-
alum is 0.888 gramme of ammonium chloroplatinate equivalent? Anzs.,
1.817 gramme.—Find the weight of barium sulphate obtainable from
0.522 of barium nitrate? Ana.. 0.466—Describe the usual method by
which calcium is determined.—By what quantitative process may the
official magnetism salts be analyzed ?—Calculate the proportion of pure
zinc sulphate in a sample of crystals 0.574 gramme of which yield
0.161 gramme of oxide; Ans., 99.4 percent.—Ascertain the weight of
alumina (AleOs) which should be obtained from 1.812 gramme of am-
monium-alam,
IRON,
[ron and its salts are gravimetrically determined in the
form of ferric oxide (Fe,O,).
Compounds containing organic acid radicals are simply in-
cinerated, and the resulting oxide weighed. Thus 1 gramme
of the official iron and ammonium citrate (Ferri et Ammonti
Citras, U.S. P.), incinerated, with exposure to air, leaves 0.31
or 0.32 of ferric oxide. A small quantity of the salt is
weighed in a tared covered porcelain crucible and the flame
enutiously applied until yapors are no longer evolved. The
650 GRAVIMETRIC ANALYSIS.
lid is then removed, the crucible slightly inclined and ex-
posed to a red heat until all carbonaceous matter has disap-
peared, After cooling, the residual ferric oxide is weighed.
The iron and potassium tartrate ( Ferrt et Potassii Tartras,
U.S. P.), is treated in the same manner, except that the ash
must be washed in order to remove potassium carbonate pro-
duced during incineration, and again heated before weighing ;
5 grammes should yield about 1.5 grammes of ferric oxide.
From other compounds of iron, soluble in water or acid, the
iron is precipitated in the form of hydroxide, Fe(OH), by
solution of ammonia, and converted into oxide (I*e,O,), by
ignition. Dissolve a piece (0.2 gramme) of the purest iron
obtainable (piano-wire ), acc urately weighed, in dilute hydro-
chlorie acid ; add a few drops of nitric acid, and gently boil;
add excess of ammonia, stir, set aside until the ferric hydroxide
has deposited, pass the supernatant liquid through a filter,
treat the precipitate three or four times with boiling water ;
transfer to the filter, wash until the filtrate yields no trace of
chloride (for ammonium chloride will decompose ignited ferric
oxide, with volatilization of ferric chloride), dry, ignite, and
weigh. Iron in the official solutions (Liquor Ferri et Am-
moni Acetatis, Liquor Ferri Chioridi, Liquor Ferri Subsul-
phatis, and Liquor Ferri Tersulphatis) may be determined by
this general gravimetric process.
The proportion of metallic iron in a mixtureof iron and iron
oxides may be determined hy digestion in a concentrated solu-
tion of iodine and potassium iodide, which attacks the metal
ang. The reduced iron of pharmacy (Ferrum Reductum,
U.S. P.), should contain not less than 90 percent, of free
ey
Proportional Weights of Equivalent Quantities of Tron
and some of its Compounda,
Metal... «4 «6 wi 6 B® 6s oe ew 8 eee
Ferric oxide = vielen) Gee 0, « <> = eee
Ferric hydroxide . . 2F e(C \H), « . « « » « BERS
Ferric chloride . . . .2FeCl, ....., . .g2n08
Ferric sulphate . . . . Fe, (80, ee . « » 897,05
Ferrous sulphate . . . 2{ FeSO, »iH,O). . . . SD208
ARSENIC.
Arsenous anhydride (As,O,) and arsenous compounds are
usually determined volumetrically (see p. 629). Arsenic can
DETERMINATION OF ARSENIC. 651
be wholly converted into hydrogen arsenide and determined
quantitatively by absorbing the hydrogen arsenide in silver
uitrate solution (p. 204). Toward the end of the operation,
a solution of stannous chloride in hydrochloric acid is added
to the contents of the vessel in which the gas is being evolved.
This causes the precipitation of any arsenic still remaining in
the solution, in a very finely divided state, in which it is read-
ily attacked by the nascent hydrogen and converted into
hydrogen arsenic (Schmidt).
Process 1.—With certain precautions arsenic may be pre-
cipitated and weighed as sulphide (As,S,). The pure white
arsenic in lump (about 0.2) is dissolved in a flask in small
quantity of water containing sodium or potassium bicarbonate,
the liquid being heated. <A slight excess of hydrochloric
acid is then added, and hydrogen sulphide gas passed through
the solution so long as a precipitate falls, the mouth of the
flask being stopped by a plug of cotton-wool (to prevent undue
access of air aud consequent decomposition of the gas, resulting
in precipitation of sulphur). The mixture is warmed in the
flask and carbonic anhydride passed through it until the odor
of hydrogen sulphide has nearly disappeared; the precipitate
is collected on a tared filter, washed as quickly as possible
with hot water containing a little hydrogen sulphide, dried in
a water-oven, and weighed. 196.64 parts of white arsenic
should yield 244.46 of arsenous sulphide.
Process 2.—The arsenic must be present in the highest state
of oxidation. Ifthe operator is not certain that this is the
ease, the solution must be warmed with a little hydrochloric
acid and a few crystals of potassium chlorate added until a
distinct chlorous odor is evyolyed—which is then allowed to
escape by continued application of heat. To the solution thus
obtained ammonia, which must produce no turbidity, is added
in excess, and then magnesia mixture (see under * phos-
phates,” p, 667). The solution is set aside for twenty-four
or forty-eight hours. The precipitate is collected on a filter
and washed with as little ammonia water (1 to 3) as posssible
until the filtrate no longer gives a reaction for chlorides, The
precipitate is then dried on the filter, the filter-paper burned
apart from the precipitate, and the whole gently ignited in a
porcelain crucible, and weighed. ‘This residue is magnesium
pyro-arsenate, and has the formula Mg,As,O,.
Note.—For the determination of minute quantities of arsenic,
in such liquids as beer, and in brewing materials and fuel,
652 GRAVIMETRIC ANALYSIS.
Thorpe’s adaptation ' of Bloxam’s electrolytic method may be
employed.
ANTIMONY.
The metal is precipitated in the form of sulphide (Sb,5,),
with the precautions observed in determining arsenic—a ama
quantity of tartaric acid, as well as hydrochloric, being added
to prevent the precipitation of an oxysalt. If the hydrogen
sulphide be passed through a hot solution, the particles of pre-
cipitate aggregate better and may be more quickly filtered
and washed, The experiment may be performed with about
half a gramme of pure antimony and potassium tartrate ; the
salt should yield nearly half its weight of sulphide. Acecord-
ing to Fresenius, the sulphide dried at 100° C, still contains 2
percent. of water, and must be heated in a current of carbonic
anhydride, until it turns from an orange to a black color,
before all moisture is expelled. The purity of antimony
and potassium tartrate, U. S. P., may be determined by the
above process.
For the volumetric determination of antimony in anti-
monious salts, see p. 630,
COPPER.
Copper may be determined as metal or as cupric oxide
(CuO). Sometimes it is precipitated and weighed as cuprous
thiocyanate or precipitated as cupric sulphide and weighed as
cuprous sulphide.
Process 1.—Dissolve about half a grammeof dry ecrystal-
lized cupric sulphate in a small quantity of water, in a tared
porcelain crucible or beaker, acidulate with hydrochloric
acid, introduce a fragment or two of pure zine, cover the
vessel with a watch-glass, and set aside until evolution of hydro-
gen has ceased and the still acid liquid is colorless, The
copper is then washed with hot water by decantation until no
trace of acid remains, the precipitate is drained, rinsed with
alcohol, dried in the water-oven, cooled, and weighed.
Process 2.—F rom a solution acidulated with sulphurie acid
and placed in a platinum crucible, copper may be entirely
‘Communicated to the Chemical Society of London on June 17, 1908,
Journ, Chem, Soc,, 83,969 and 974.
DETERMINATION OF COPPER. 653
deposited in a coherent form by a weak current of electricity,
the crucible being connected with the zine pole of the battery,
a platinum spatula suspended in the solution forming the
positive pole. The crucible may afterward be freed from
the deposited copper by means of nitric oxide.
Process 3.—About 0.75 gramme of cupric sulphate 1s
dissolved in half a litre of water, and the liquid boiled ;
dilute solution of potassium or sodium hydroxide is then added
until no more precipitate falls, ebullition continued for a short
time, and the beaker set aside; the supernatant liquid is
decanted, the precipitate boiled with water twice or thrice,
collected on a filter, washed, dried, transterred to a porcelain
crucible, the filter incinerated, added to the precipitate in the
crucible and moistened with a drop of nitric acid; the whole
is finally heated strongly, cooled, and weighed. This process
can only be employed in absence of organic substances, as
certain organic compounds such as tartaric and citric acids
prevent the complete precipitation of the cupric oxide.
247.85 parts of erystallized cupric sulphate should yield
78.98 of oxide, or 63.1 of metal.
The cupric oxide obtained as above almost always weighs
more than the theoretical proportion as it is practically impos-
sible to wash it free from alkali.
Process 4.—About half a gramme of cupric sulphate may
be taken, dissolved in about 200 Ce. of water and a few drops
of hydrochloric acid added. <A solution containing equal
quantities of ammonium thiocyanate and ammonium (or
solium) bisulphite is then added until no further precipita-
tion takes place. The whole is heated and after the white
precipitate of cuprous thiocyanate has settled, the clear liquid
is poured through a previously weighed filter, the precipi-
tate washed by decantation, transferred to the filter, washed
further until no trace of chloride is found in the filtrate, dried
in the water-oven (or preferably in an air-bath at a tempera-
ture of 110° C.), cooled and weighed.
120.77 grammes of cuprous thiocyanate (CuCNS) represent
63.1 grammes of copper.
The determination of copper as cuprous sulphide involves
the use of special apparatus and the ignition of the precipitate
with sulphur in an atmosphere of hydrogen,
654 GRAVIMETRIC ANALYSIS.
BISMUTH.
Dissolve 0,3 or 0.4 of the pure bismuth subcarbonate
(Bismuthi Subcarbonas, U.S. P.), in a very small quantity
of hydrochloric acid, dilute with water slightly acidulated
with hydrochloric acid, pass excess of hydrogen sulphide
through the liquid, collect the precipitate on a tared filter,
wash, dry at 212° F. (100° C.), and weigh. The sulphide
must not be exposed too long in the water-oyen, or it will
increase in weight owing to absorption of oxygen, hence it
should be tested in the balance every half-hour until it no
longer loses weight. In testing the official preparation of
bismuth, the U. 8. P. directs that certain compounds (subear-
bonate, subnitrate) be simply ignited in a porcelain crucible
and the resulting bismuth oxide weighed ; and that other com-
pounds, (citrate subgallate, etc.), be first ignited, the residue
dissolved in nitric acid, the solution evaporated to dryness,
and the residue ignited so as to form bismuth oxide, which is
to be weighed.
MERCURY.
This element may be (1) isolated and determined in the form
of metal, or precipitated and weighed as (2) mercurous chlo-
ride, or (3) mercuric sulphide.
Fics. 78, 79, 80.
Process 1.—The process by which the metal itself is sepa-
rated is one of distillation into a bulb surrounded by water,
About half a metre of the difficultly fusible German glass
known as combustion-tubing is sealed atone end after the
manner of a test-tube (Fig. 78); a mixture of sodium bicar-
bonate and dry chalk is then dropped into the tube to the
height of two or three centimetres, and, next, seyeral smal]
fragments of quicklime so as to occupy another centimetre ;
DETERMINATION OF MERCURY. 659
a mixture of about a gramme of pure calomel or corrosive
sublimate with enough powdered quicklime to occupy 10 or
12 centimetres of the tube is added, then the lime-rivsings
of the mixing-mortar, a layer for a few centimetres of pow-
dered quicklime, and, finally, a plug of asbestos. The whole
should occupy two-thirds of the tube. The part of the tube
just above the asbestos is now softened in the blowpipe-
tliame and drawn out about a decimetre to the diameter of a
narrow quill (Fig. 79); again drawn out to the same extent at
a point two or three centimetres nearer the mouth (Fig. 79)
and any excess of tubing cut off. The bulb thus formed may
be enlarged by softening and blowing. The tube is next
softened at a point close to but anterior to the asbestos, and
bent to form an obtuse angle; the tube is then softened close
to the bulb and slightly bent so that the bulb may be
parallel with the long tube; then softened on the other side
Fie, 81.
of the bulb, and the terminal tube bent to an obtuse angle,
80 that, the tube being held in a horizontal position, the bulb
may be sunk in the water, and the terminal tube point upward
(Fig. 80). The long tube is now laid in the gas-furnace
(Fig. 81), a basin so placed that the bulb of the apparatus
may he cooled by being surrounded by water, the part of the
tube occupied by asbestos heated to redness, and the flame
slowly lengthened until the tube is uniformly red-hot. In
the circumstances just described the mereury compound is
decomposed by the lime and its acid radical fixed, and the
mercury carried in vapor to and condensed in the bulb,
The carbonic anhydride evolved from the sodium bicarbonate
and chalk washes out the last portions of mercury vapor
656 GRAVIMETRIC ANALYSIS.
from the tube. When the distillation is considered to he
complete, the dish of water is removed, the bulb dried, and
then detached by help of a file, at a point beyond any sub-
limate of mercury, ‘The dried bulb is weighed, the mercury
shaken or dissolved out, and the tube again dried and
weighed. The difference between the weights gives the
weight of the mercury. ‘“Ammoniated Mercury,” U. 5. P-.,
should yield 78 to 80 percent, of metallic mercury.
Process 2.—The process by which mercury is separated in
the form of calomel, consists in adding, in the cold, solution of
hydrochloric and phosphorous acids to an aqueous or even
acid solution of a weighed quantity of the mercurial com-
pound, setting the mixture aside for twelve hours, collecting
the precipitate on a tared filter, washing, drying at 212° F.
(100° C.), and weighing (Rose). By adding first excess of
hydrogen peroxide, then phosphorous acid, and warming on &
water-bath until the precipitate is flocculent, the reaction is com-
pleted in a few minutes without reduction of calomel to
metallic mercury as is the case when the mercurie chloride
solution is heated with phosphorous acid. The experiment
may be tried on about half a gramme of corrosive sublimate.
Process 3.—T'wo or three decigrammes of corrosive subli-
mate are dissolved in water, the solution acidulated with hydro-
chloric acid, excess of hydrogen sulphide passed through it,
the precipitate collected on a tared filter, washed with cold
water, dried at 212° F.(100° C.), and weighed.
Proportional Weights of Equivalent Quantities of Mereury
and ita Salta,
Mercury . , | ... Ag. .«1s eee
Mercurous chloride . . .HgCl..,.. . . 288,68
Mercuric chloride. . , , HgCl,. . .. . . . 268,86
Mercuric sulphide. ..HgS...... . ~ 230,38
Lead is generally determined either as (1) oxide, ( 2) sul-
phate, (3) chromate, or (4) metal. a
Process 1.—Weigh out one or two grammes of pure lead
acetate in a covered crucible, previously tared, and heat slowly
until no more vapors are evolyed. Remove the lid, stir down
the carbonaceous mass with a clean iron wire, and keep the
crucible in the flame so long as any carbon remains uncon-
sumed, Introduce some fragments of fused ammonium nitrate,
DETERMINATION OF LEAD, 65T |
and again ignite until no metallic lead remains and all excess
of the nitrate has been decomposed. Cool and weigh the
resulting oxide (PbO),
Process 2.—Dissolve 0.4 or 0.5 gramme of lead acetate in
a small quantity of water, drop in dilute sulphuric acid, add
to the mixture twice its bulk of alcohol, and set aside,
Decant the supernatant liquid, collect the sulphate on a filter,
wash with alcohol, dry, transfer to a porcelain crucible,
removing as much of the sulphate as possible from the paper,
incinerate on the crucible-lid (not in the platinum coil, for
the fused particles of reduced lead would alloy with the
platinum ), ignite, cool, and weigh.
Process 3.—About half a gramme of lead acetate is dis-
solved in two to three hundred Ce. of water, acetic acid
added, and then solution of potassium dichromate. Collect
the precipitate on a tared filter, wash, dry at 212° F. (100°C. ),
and weigh,
Process 4.—In certain cases, notably in that of commercial
“white lead,” the leal may be determined in the metallic
state by means of potassium cyanide. The lead paint (about
20 grammes) is weighed and carefully incinerated. The
residue, a mixture of metallic lead and lead oxide, is then
mixed with several times its bulk of potassium cyanide, and
the whole heated to fusion. With careful manipulation the
lead collects in one globule, which, after cooling, may readily |
be separated from the mixed cyanide and cyanate, and
weighed. Commercially pure white lead should yield 74 per-
cent. of lead.
Volumetric Determination of Lead.
In lead acetate and in the strong solution of lead subacetate
the lead may be determined volumetrically by means of nor-
mal solution of sulphuric acid. About 3 grammes of lead
acetate or from 7 to 10 grammes of the subacetate solution
may be used,
Pb(C,H,0,),,83H,0 + HSO, = PbSO, + 2HC,H,O, + 3H,O0
2)376, 15 2)97.35
LK. 075 48.075 <grammes in 1000 Ce. of normal solution.
Pb,0(C,H,0,), + 2H,80, = 2PbS0, + 2HC,H,O, + H,O
en, —_
4)548.74 4)194.70
135.93 48,675 =crammes fn 1000 Ce, of normal solution.
42
———
658 GRAVIMETRIC ANALYSIS.
The flask in which the operation is being condueted should
previously contain one-third of water. In the case of both
lead acetate and solution of lead subacetate, a little acetic acid
should be added to prevent precipitation of basic salt on dilu-
tion. The only indicator of complete reaction is cessation of
production of the precipitate—lead sulphate. The United
States Pharmacopwia requires lead acetate to contain not less
than 99.5 percent. of pure Lead Acetate, and solution of lead
subacetate to contain not less than 25 percent. of lead sulb-
acetate,
Proportional Weights of Equivalent Quantities of Lead and
of some of its Compound,
Lead . 8 © & oe ee Oe ow Pb oe PF « se @ a fe 20. on
Lead acetate. . . . . . Pb(C,H,O,),5H,O. . 876.15
Lead oxide... ....,PbDO (3.54545 omen
Lead sulphate... . . PbSO, .... . - 300.70
Lead chromate. . . . . PbCrO, .... . «320.57
SILVER.
Silver in compounds which are readily decomposed by heat
is determined as (1) metal, in others usually as (2) chloride
(AgCl), but sometimes as (3) evanide (AgCN).
Process 1.—Heat about a gramme of silver oxide, Ag.O, in
‘a tared crucible, cool, and weigh. 230,12 of oxide yield
214.24 of metal.
Process 2.—Dissolve 0.4 or 0.5 gramme of pure dry crystals
of silver nitrate in water, acidulate with two or three drops
of nitric acid, slowly add hydrochloric acid, stirring rapidly,
until no more precipitate is produced. Pour off the superna-
tant liquid through a filter, wash the silver chloride once or
twice wit h hot water, transfer to the filter, complete the wash-
ing, and dry. After removing as much as possible of the
precipitate from the paper to the crucible, burn the filter, not
ina wire helix but on the inverted lid of the erucible, moisten
with a drop of nitric acid, warm, add a drop of hydrochlorie
acid, evaporate to dryness, replace the lid on the erueible,
ignite the whole until the edges of the mass of chloride begin
to fuse; cool, and weigh. 168.69 of nitrate yield 142.3 of
chloride. 3 parts of Mitigated Silver Nitrate ( Argenti Nitras
Mitigatus, U.S. P.), similarly treated, give 0.843 parts of
silver chloride, and the filtrate yields potassium nitrate and
DETERMINATION OF ACID RADICALS. 699
chloride on evaporation. 10 parts of silyer dissolved in nitric
acid and treated as above will, if pure, give 13.285 of silver
chloride,
Process 3.—Silver cyanide may be collected on a tared filter
and dried at 100°C. 168.69 of nitrate yield 132.96 of
cyanide.
Silver and its salts may be determined volumetrically by
means of a standard solution of sodium chloride,
Cupellation.—The percentage of silver in an alloy may be
determined by adry method. The metal is folded in a piece of
thin sheet lead, placed on a eupel (eupella, little cup, made
of compressed bone-earth) and heated in a furnace, the cupel
being protected from the direct action of the flame by a case
termed a muffle. The metals melt, the baser become oxidized,
the lead oxide fusing and dissolving the other oxides ; the
fluid oxides are absorbed by the porous cupel, a button of
pure silver remaining. An alloy suspected to contain 95 per
cent. of silver requires about three times its weight of lead
for successful cupellation ; if 90 percent. (U. 8. silver coin),
seven times its weight of lead is necessary.
SS ee
QUESTIONS AND EXERCISES.
Explain the gravimetric process by which the concentration of solu-
tions of ferric chloride, nitrate, and sulphate may be determined.—Men-
tion the various amounts of ferrous and ferric salts equivalent to 100
parts of iron.—State the precautions necesssary to be observed in
determining arsenic or antimony in the form of sulphide.—In what form
are the official compounds of bismuth weighed for quantitative purposes?
—Give an outline of the process by which mercury may be isolated from
its official preparations and weighed in the metallic condition.—Give three
methods for the quantitative analysis of lead salts; and the weights of
the respective precipitates, supposing 0.56 grm, of crystallized acetate to
have been operated on in each case.—Describe the processes by which
silver is determined in the forms of metal, chloride and cyanide.—Whut
proportions of silver nitrate are indicated, respectively, by 15 of metal,
9.8 of chloride, and 8.1 of cyanide ?—Describe cupellation.
DETERMINATION OF ACID RADICALS.
CHLORIDES.
Free chlorine (chlorine-water) and compounds whieh by
action of acids yield free chlorine (Chlorinated Lime, Chlorin-
ated Soda, and their Solutions) may be determined yolu-
660 GRAVIMETRIC ANALYSIS.
metrically by a standard solution of sodium thiosulphate (see
p. 635). The quantity of combined chlorine in chlorides
may be determined by volumetric analysis with a standard
solution of silver nitrates (p. 624),
Combined chlorine is gravimetrically determined in the form
of silver chloride, the operation being identical with that
described for silver salts (p. 658). 58.06 parts of pure,
colorless, crystallized sodium chloride yield 142.3 of silver
chloride,
IODIDES.
Free iodine is determined yolumetrically by means of solu-
tion of sodium thiosulphate (see p. 636).
Combined iodine is determined gravimetrically in the form
of silver iodide, the operations being conducted as with silver
chloride, Potassium iodide may be used for an experimental
determination : KI—164,76 should yield AgI-—233.02.
Moisture in iodine is roughly determined by loss on expos-
ing a weighed sample on a watch-glass placed in a desiccator
over sulphuric acid. Another method consists in adding to
a weighed sample five or six times as much mercury, or
excess of zinc or silver filings, and a little water, drying and
weighing. The weight of the product is the weight of metal
employed plus that of the dry iodine in the sample.
BROMIDES.
Free bromine may be determined by shaking with excess
of solution of potassium iodide, and then determining the
equivalent quantity of liberated iodine by means of a standard
solution of sodium thiosulphate (p. 635).
The bromine in bromides may be precipitated and weighed
as silver bromide, the manipulations being the same as those
for silver chloride: 0.2 to 0.3 gramme of pure potassium
bromide may be used for an experiment.
CYANIDES.
Hyd rogen cyanide ( hyd rocyanic acid ) is usually determined
volumetrically (see p. 625).
From all soluble cyanides cyanogen may be precipitated
by silver nitrate, after acidulating with nitrie acid, the silver
cyanide being collected on a tared filter, dried at 100° C., and
weighed,
DETERMINATION OF NITRATES. 661
Silver Cyanide,
In formula wt. In 100 parts,
Selvet i s A a oo tot MORASS. SOG a8b
Cyanogen . ON... ... 20.84... . 19.435
182.96 100,00
—
NITRATES.
Nitrates cannot be determined by direct gravimetric
analysis, none of the metallic radicals yielding a definite
nitrate insoluble in water. With some difficulty they may be
determined by indirect volumetric methods.
Fie, 82.
Determination of nitrates,
Process.—The following (Thorpe’s) method depends upon
the fact (Gladstone and Tribe) that when zine upon which
copper is deposited in a spongy form is boiled with water,
hydrogen is evolved. Thorpe found that in a solution con-
taining nitrates the nascent hydrogen converts the whole of
the nitrogen of the nitrates into’ ammonia, which may be
collected and determined. (The oxygen of the nitrate is
simultaneously converted into water, the metallic radical into
hydroxide, and the zine into zinc hydroxide. The power of
the copper-zine couple is considered to depend largely on the
hydrogen absorbed by the finely divided metal.)
An apparatus such as shown in Fig, 82 should be con-
structed. <A flask (about 100 Ce.) is fitted with a clean
sound cork perforated for a delivery-tube, which should be
662 GRAVIMETRIC ANAL YSIS.
of strong glass tubing of about a quarter-inch bore, and for a
stoppered funnel, which should have about half the capacity
of the flask. The whole is supported by a clamp or on wire-
gauze. The outer jar shown in the figure should have a
capacity of two or three litres, and the inner receiving-jar
should be capable of holding 200 Ce. The latter is fitted
with a cork perforated for the delivery-tube, and perhaps for
another tube containing fragments of glass moistened with
acidulated water to prevent possible loss of ammonia—though
the latter tube is found to be almost unnecessary. The addi-
tion of wash-bottle tubes is also recommended as convenient
for obtaining the distillate from the jar without dismounting
the apparatus from time to time,
A few strips of clean zine (granulated zine recently cleansed
with dilute acid is best), are boiled in a beaker with a 3 per-
cent. solution of cupric sulphate, the operation being repeated
with a fresh portion of solution until an adherent and fairly
thick coating of finely divided copper is deposited. The
pieces of metal are well washed and introduced into the flask,
which is then half filled with pure water free from ammonia.
To avoid transference, the flask itself may be used instead of
the beaker. The funnel also of the apparatus is filled with
pure water. Water is now placed around the inner receiver
in the outer jar, and, the connections being sound, heat is
apphed with the view of freeing the apparatus itself from any
trace of ammonia. When the contents of the flask are evapo-
rated nearly to dryness, pure water is admitted from the fun-
nel until the flask is again about half full (the funnel should
be filled again at once), and the distillation carried on as
before. This must be repeated until no further trace of
ammonia is evolyed, when the apparatus is ready for use.
On each oecasion that the ary is used it must be freed
from ammonia in this way. <A suitable quantity of the sub-
stance to be examined is now introduced (in the case of
potable waters the prepared solid residue from 100 Ce.) and
water added, if necessary, until the flask is half full. Heat
is now applied and the operation conducted in the manner
alre audy describe -d untill ammonia no longer comes oyer—a point
which usually occurs in the case of water-residues when the
flask has been twice or thrice charged with water and the
pistillate | is about 100 Ce. The warm water from the upper
part of the cooling-jar may be removed by a siphon or other-
wise, cold water being introduced from time to time,
DETERMINATION OF SULPHIDES. 663
The ammonia being all evolved, disconnect the flask and
receiver simultaneously (unless wash-bottle tuhes are fitted ),
and treat the contents of the latter by the Nessler method
described on page 616.—Urea yields but traces of ammonia
by this process; and neither the sulphates nor chlorides of
the alkali-metals affect the result.—The method is only
applicable to highly dilute solutions of nitrates, for with more
* concentrated solutions oxides of nitrogen are formed and escape.
SULPHIDES.
Process 1.—Soluble sulphides (¢.g., H,S, NaHS) may be
determined volumetrically by adding to the aqueous liquid a
measured excess of an alkaline arsenous solution of known
concentration, neutralizing with hydrochloric acid, diluting to
any given volume, filtering off the arsenous sulphide pre-
cipitated, taking a portion of the filtrate equal to a half or a
third of the original volume, and, after neutralizing with
sodium bicarbonate, determining the residual arsenic by
means of the standard iodine solution (see p. 629).
Process 2.—Sulphur and sulphides may also be quantita-
tively analyzed by oxidizing to sulphuric acid and precipita-
ting in the form of barium sulphate. Thus 2 or 3 deei-
grammes of a pure metallic sulphide may be decomposed by
careful deflagration with a mixture of potassium chlorate and
sodium carbonate, the product dissolved in water, acidulated
with hydrochloric acid, solution of barium chloride added,
and the precipitated barium sulphate washed and collected
as described in connection with the estimation of barium
(p. 645). Many sulphides may be oxidized by heating in a
flask with potassium chlorate and hydrochloric acid, and the
sulphate formed is then precipitated by burium chloride.
Experimental determinations may also be made on a weighed
fragment of sulphur, about 0.1 gramme cautiously fused with
asmal! quantity of sodium hydroxide, and the product oxidized
while hot by the slow addition of powdered potassium nitrate
or chlorate, or, when cold, by treatment with potassium
chlorate and hydrochloric acid, the sulphate obtained being
subsequently precipitated by barium chloride.
Note,—Fusions performed over a Bunsen flame must be enre-
fully conducted; for any alkali that may creep over the side of a
crucible will certainly absorb sulphurous anhydride from the prod-
ucts of combustion of the gas, and error will result,
664 GRAVIMETRIC ANALYSIS.
Process 3.—Soluble sulphides may also be treated with
excess of an alkali-metal arsenite, arsenous sulphide them be
precipitated by the addition of hydrochlorie acid, and the
precipitate collected and weighed with the usual precautions
(see p, 691).
Weights of Equivalent Quantities of Sulphur and some of ils
Compound,
Galpline’ «.. 's-%. ten ere
Hydrogen sulphide. . HS ote ee (SOBe
Barium sulphate. . . SO, . 1 + + 6s BOLO
Arsenous sulphide . . 35,)- oe ea
Iron pyrites .... : ~% ~~ 99,58
Lead sulphide ... ree
Sulphites are usually determined volumetrically by means
of a standard solution of iodine (see p. 628). Sulphites
insoluble in water are diffused in that menstruum, hydrochloric
acid added, and the iodine solution then dropped in. ’
_ If necessary, sulphites may be determined gravimetrically
by oxidation as barium sulphate,
SULPHATES.
These salts are always precipitated and weighed as barium
sulphate, the manipulations being identical with those per-
formed in the determination of barium by means of sulphates
(see p. 645). ~The puri ty of Sodium Sulphate ( Sodu Sulphas,
U.S. P.), and the presence of not more than a given quantity of
sulphuric acid in vinegar, may be ascertained by this proces,
‘Ten grains of sodium sulphate yield 7.24 of barium sulphate,
Five ounces of vinegar should yield not more than about 4
gramme of barium sulphate.
_ Sulphates may be determined volumetrically by means of a
halfnormal solution of pure barium chloride.
The quantity of free sulphuric or hydrochlorie acid in vin-
egar, lemon juice, lime juice, ete, may be ascertained yolu-
metrically by adding a known quantity of standard solution
of sodium hydroxide, evaporating to dryness, incinerating,
dissolving in water, and by standard acid determining the
quantity of sodium hydroxide still remaining free The
sodium hydroxide lost indicates the amount of free mineral acid
DETERMINATION OF CARBONATES, + 665
(Hehner). Thresh first determines the chloride in a sample
of vinegar, then adds a known additional amount of chloride,
preferably in the form of barium chloride, evaporates, ignites,
treats with water, adds sodium bicarbonate to remove excess
of barium, filters, and again determines the chlorine. A
loss of 70.36 of chlorine (Cl,) indicates 97.35 of free sulphuric
acid (H,SO,).
The method of determining free sulphuric, nitric, and
hydrochloric acids, proposed by Spence and KEsilman, is
founded on their power of decolorizing a standard solution of
ferric acetate.
Proportional Weights of Equivalent Quantities of Sulphates,
The sulphuric radical . . . . BO... .. 4. ; 95.35
Sulphuric acid... AO.” Pat ttcen 97.35
Barium sulphate. ...,. BaSOQ,..... 231.75
CARBONATES.
Carbonates are usually determined by the loss in weight
they undergo on the addition of a strong acid,
Process 1.—A small light flask is selected—of such a size
that it can be conveniently weighed in a delicate balance.
Two narrow glass tubes are fitted to the flask by means of a
cork—the one straight, extending from
about two or three centimetres above the Fig. 83,
cork to the bottom of the flask, the other |
cut off close to the cork on the inside
and curved outward so as to carry a thin
drying-tube horizontally above the flask
(see fig. 83). Thedrying-tube is nearly
filled with small pieces of calcium chlo-
ride, a plug of cotton-wool at either end
reventing escape of any fragments, and
is attached by means of a pierced cork to :
the free extremity of the curved tube of agen ream op as
the flask. A weighed quantity of any
pure soluble carbonate is placed in the flask, a little water
added, a miniature test-tube containing sulphuric acid lowered
into the flask hy means of a thread and supported so that the
acid may not flow out, the cork inserted, the outer end of the
piece of the straight glass tubing closed by a cap or a frag-
ment of cork, and the whole weighed, ‘The apparatus is then
‘. —
666 GRAVIMETRIC CHEMISTRY.
inclined so that the sulphurie acid and carbonate may slowly
interact; carbonic anhydride is evolyed and escapes through
the horizontal tube, any moisture being retained by the caleium
chloride, When effervescence has ceased, the gas stil] remain-
ing in the vessel is sucked out ; this is accomplished by fixing
a piece of India-rubber tubing to the end of the drying-tube,
removing the small plug from the straight tube, and aspirating
slowly with the mouth for a few minutes. Ifthe heat produced
by the action of the sulphuric acid and solution is considered
insufficient to expel all the carbonic anhydride from the liquid,
the plug is again inserted in the tube and the contents of the
flask gently boiled for some seconds. When the apparatus is
nearly cold, more air is again drawn through it, and the whole
finally weighed. The loss is due to carbonic anhydride (CO,),
from the weight of which that of any carbonate is ascertained
by calculation. Carbonates insoluble in water may be attacked
by hydrochloric instead of sulphuric acid; granulated mix-
tures of carbonates and powdered tartaric or citric acids by
enclosing the preparation in the inner tube and placing water
in the flask, or vice versd, The apparatus may be modified in
many ways to suit the requirements, convenience, or practice
of the operator.
Process 2.—Carbonates from which carbonic anhydride is
evolved by heat may be determined by the loss they experi-
ence on ignition,
Process 3.—Free carbonic anhydride may be absorbed b
a solid stick of potassium hydroxide or concentrated alkali
solution, the loss in volume of the gas or mixture of gases
indicating the quantity originally present.
Weights of Equivalent Quantities of Carbonie Anhydride
and certain Carbonates.
Carbonic anhydride... .. , CO, .. . « + Sa67
Carbonic acid ..... ...H 0, .. . .t0 2 ee
Anhydrous sodium carbonate _ Na, CO, . . . 105,31
Ory stalline sodium carbonate Na. CO, LOH, 0 284.11
A nhydrous potassium carbonate K CO, . » ve Sedge
Calcium carbonate a ea _ Cac, .» « 99.36
OXALATES.
Process 1.—The oxalic radical is usually precipitated in the
form of calcium oxalate, and weighed as carbonate, the manip-
ulations being identical with, those observed in the determina-
DETERMINATION OF PHOSPHATES. 667
tion of calcium (see p. 646). The experiment may be per-
formed on 0.3 or 0.4 gramme of pure oxalic acid, 125.1 parts
of which should yield 99.35 of calcium carbonate,
Process 2.—Oxalates may also be determined by conversion
of their acid radical into carbonic anhydride, and observation
of the loss of weight due to escape of the latter. The oxalate,
water, and excess of black manganese oxide are placed in the
carbonic anhydride apparatus (p. 665), a tube containing sul-
phurie acid lowered into the flask, the whole weighed, and
the operation completed as for carbonates. From the follow-
ing equation it will be seen that each 87.54 parts of carbonic
anhydride evolved indicates the presence of 125.1 parts of
crystallized oxalic acid or an equivalent quantity of other
oxalate :—
Na, 0,0, + MnO, + 3H,8O, = MnSO, + 2NaHSO, + 2H,0 + 200,
The black manganese oxide used in this experiment must be
free from carbonates. The quantities of the materials em-
ployed are regulated by the size of the vessels.
Process 3.—(xalic acid and oxalates may be determined
volumetrically by. means of a standard solution of potassium
permanganate (see p. 654).
PHOSPHATES.
Process 1.—F'rom phosphates soluble in water the phosphoric
radical may be precipitated and weighed in the form of mag-
nesium pyrophosphate, the details of manipulation being simi-
lar to those observed in determining magnesium (see p. 647).
Half a gramme or rather more of pure dry crystallized sodium
phosphate may be employed in experimental determinations.
Solution of magnesium ammonio-sulphate known as Magnesia
Mixture, (U. 8. P.), is prepared by dissolving 10 parts of
magnesium sulphate and 20 of ammonium chloride, in 80 of
distilled water and adding 42 Ce. of ammonia water. ;
Process 2.—F'ree phosphoric acid is most readily deter-
mined as lead phosphate PhPO,),, by evaporating it to dry-
ness with excess of pure lead oxide and heating to dull red-
ness. ‘T’he lead oxide must be quite pure; it should be pre-
pared by digesting red lead in warm dilute nitrie acid, wash-
ing, drying, and heating the resulting pure-colored lead per-
oxide in «a covered porcelain crucible until it is completely
converted into lead oxide (PbO). The increase in weight
obtained on evaporating a given quantity of solution of phos-
668 GRAVIMETRIC ANALYSIS,
phoric acid with a known weight of perfectly pure lead oxide
may be regarded as entirely due to phosphoric anhydride
(P.O,); 3PbO + P,O,—Pb,(PO,),, the actual reaction being
3PbO ++ 2H,PO, = Pb,(PO,), + 3H,O. From these equa-
tions, and the atomic weights (see Appendix or Table on p,
59), the percentage of phosphoric acid (H,PO,) im any
specimen of its solution may easily be calculated, }
Process 3.—The official Calei:x Phosphas Precipitatus, and
other forms of calcium phosphate known to be tolerably free
from iron or aluminium, may be determined by treating about
half'a gramme with hydrochloric acid somewhat diluted, filter-
ing, if necessary, warming, adding excess of ammonia, collect-
ing the precipitate (Ca,(PO,),), washing, drying, igniting
and weighing. The calcium phosphate of pharmacy, if pure,
will in this process lose little or no weight.
Process 4.— Insoluble phosphates in ashes, manures, ete., are
treated as follows: The weighed material (1.0 to 10.0
grammes) is digested in hydrochloric acid diluted with three
or four times its bulk of water, filtered (insoluble matter and
filter being thoroughly exhausted by water), ammonia added
to the filtrate and washings, until, after stirring, a faint cloudy
precipitate is perceptible, solution of oxalic acid dropped in
until, after agitation for a few minutes, the opalescence is
destroyed, ammonium oxalate next added, the whole warmed,
calcium oxalate removed by filtration, and the filtrate con-
centrated if very dilute, the liquid treated with citric acid in
such quantity that ammonia when added in excess gives a
clear /emon-yellow solution (Warington), magnesia mixture
poured in (as in process 1), and the precipitate of ammonium
magnesium phosphate collected, washed, dried, and weighed,
as already described in connection with the determination of
magnesium,
_ The concentration of pure solutions of phosphoric acid may
be ascertained by determination of specific gravity and refer-
ence to tables.
Relative Weights of Equivalent Quantities of Phosphoric
Compounds,
Phosphoricncid . . . . . H,PO,
Magnesium pyrophosphate (Mg,P,0, =221.06)+2—110.58
Lead phosphate. . . . . (Pb3( PO,), =804,68)+2=402. 916
Phosphoric anhydride . . (P,O, = 140,94)+2= 70A7
Calcium phosphate .. . 1Ona| PO,), =507.98)+2=—153.99
Calcium superphosphate . (CaH,(PO,), = 233.38) +2=116.19
DETERMINATION OF SILICATES, 669
QUESTIONS AND EXERCISES,
. What quantity of pure rock-salt is equivalent to 4.2 parts of silver
chloride? Ans., 1.71.—State the percentage of real potassium iodide con-
tained in a sample of which 8 parts yield 10.9 of silver iodide. Ans,, 96,63.
—What is the concentration of a solution of hydrocyanic acid 10 parts
which, by weight, yield 0.9 of silver cyanide? Ana,, 1.51 percent.—How
are nitrates quantitatively determined ?—By what processes may the
bean § of a sulphide present in a solution be determined 7—How much
real sodium sulphate is contained ina specimen 10 partsof which yield
14.2 of barium sulphate? Ans., 86.58 percent.—Give details of the opera-
tions Dc peere in the quantitative analysis of carbonates.—What weight
of carbonic anhydride should be obtained from 10 parts of acid potassium
carbonate (or bicarbonate)? Ans., 4.39 parts.—To what operation does
the following equation refer, and what are the relative proportions of the
reacting substances ?
NaC:O4-+- MnO: ++ 31280, = MnSO4 -+ 2NaHS0,-+-2H.,0 +200,
Explain the lead process for the determination of phosphoric acid.—State
the quantity of calcium superphosphate equivalent to 7.6 parts of magne-
parts.
*
sium pyrophosphate, <Ams,, 7.089
SILICATES.
Silica (Si0,) may be separated from alkali-metal silicates,
or from silicates decomposable by hydrochloric acid, by digest-
ing the substance with hydrochloric acid at a temperature of
70° to 80°C., until completely disintegrated, evaporating to
dryness, heating in an air-bath to a temperature of 200° C.,
again moistening with acid, diluting with hot water, filtering,
washing, drying, igniting, and weighing.
DETERMINATION OF WATER.
Water and other matters readily volatilized are most usually
determined by the loss in weight which a substance under-
goes on being heated to a proper temperature. Thus, in the
Pharmacopeeia, crystalline gallic acid (C,H,O,, H,O) is stated
to lose 9.58 percent. of its weight when dried at a temper-
ature of 100°C., cerium oxalate (Ce,(C,O,),, 9H,O) 53 per-
cent. on incineration, quinine bisulphate, (H,N,O »H,SO,,
7H,O 22.99 percent. at 100°C., and “sodium — phosphate
(Na,HPO,12H,O) 62.84 percent. at a low red heat; bis-
muth oxide heated to incipient redness should scarcely
diminish in weight.
Process.—One or two grammes of substance is a sufficient
quantity in experiments on desiccation, the material being
placed in a watch-glass, covered or uncovered porcelain
670 GRAVIMETRIC ANALYSIS.
crucible, or other vessel, according to the temperature to which
it is to be exposed,
Rapid desiceation at an exact temperature may be effected
by introducing the substance into a tube having somewhat
the shape of the letter U, sinking the lower part of the tube
into a liquid kept at a definite temperature (using a ther-
mometer ), and drawing or forcing a current of dry air slowly
through the apparatus. Substances liable to oxidation may
be desiccated in a current of dried carbonic anhydride. The
weights of the U-tube before and after the introduction of the
salt, and after desiccation, give the quantity of water sought.
In, all cases the material must be heated until it no longer
loses weight. Occasionally it is desirable to determine water
directly by conveying its vapor in a current of air through a
weighed tube containing calcium chloride, and re-weighing
the tube at the close of the operation ; the increase shows the
quantity of water.
Note.-—Highly dried substances rapidly absorb moisture from
the air; they must therefore be weighed quickly, enclosed, if pos-
sible, in tubes (p. 640), a light stoppered bottle having a wide
mouth, a pair of clamped watch-glasses, or a crucible having a
tightly fitting lid.
CARBON, HYDROGEN, OXYGEN, NITROGEN.
The quantitative analysis of animal and vegetable substances is
either proximate or ultimate.
Prorimate Quantitative Organic Analysis includes the determina-
tion of water, oil, albumin, starch, cellulose, gum, resin, alka-
loids, acids, glucosides, ash. It requires the application of much
theoretical knowledge and manipulative skill, and cannot well be
studied except under the guidance of a teacher. One of the best
works on the subject is by Rochleder, a translation of whose mono-
graphs will be found in the Pharmaceutical Journal, yol.i., 2nd
ser., pp. 562, 610; vol. ii., 2nd ser., pp. 24, 129, 160, 215, 274,
420, 478, Another is by Prescott, ‘Outlines of Proximate Or-
ganic Analysis.’" The fullest is by Dragendorff, translated by H.
G. Greenish, “‘ Plant A nalysis."’
Ultimate Quantitative Organic Analysis can only be successfully
accomplished with the appliances of a well-appointed laboratory
—n good balance, a gas combustion furnace 80 to 90 centimetres
long (p. 655), gi ving a smokeless flame, special forms of glass
apparatus, etc, ; 7 he theory of the operation 18 simple : a weighed
quantity of a substance is completely burned to carbonic anhydride
(CO,=43,67) and water (H,O=17.88), and these products are
CARBON, HYDROGEN, OXYGEN, NITROGEN. 671
collected separately and weighed ; 11,91 parts in every 43.67 of
carbonic anhydride are carbon, 2 parts in every 17.88 of water are
hydrogen ; nitrogen, if present, escapes as gas. If nitrogen be a
constituent, it may, in certain cases, be determined by strongly
heating a second quantity of the substance with the mixture of
sodium and calcium hydroxides known as soda-lime, when the
nitrogen is converted into ammonia. This ammonia may be deter-
mined volumetrically (p. 615) or it may be collected and weighed
in the form of ammonium chloroplatinate (NH,), PtCl,—440. 24),
of which 27.86 parts in every 440, 24 are nitrogen. Tn the case
of certain classes of substances containing nitrogen, the whole of
this element is not convertible into ammonia by heating with
soda-lime. In these cases the substance is burned under such con-
ditions that its nitrogen is obtained as gas, in which condition it is
subsequently measured. The difference between the sum of the
weights of hydrogen and carbon, and the weight of substance
taken, is the proportion of oxygen in the substance, supposing
nitrogen to be absent. If nitrogen is present, the difference be-
tween the sum of the percentages of carbon, hydrogen, and nitro-
gen, and 100, is the percentage of oxygen. Shortly, carbon is
determined in the form of carbonic anhydride, hydrogen as water,
* nitrogen as ammonia, or as nitrogen gas, and oxygen by difference.
The following is an outline of the manipulation necessary for
the determination of carbon and hydrogen :—The burning (or
combustion as it is usually called) of the organic substance is
carried out by heating it in a combustion-tube of hard glass
in a current of air previously freed from water vapor and
carbonic anhydride. The combustion-tube has an internal
diameter of 15-18 millimetres, and is about 90 centimetres
long, being cut to such a length that, when placed in the
furnace, it projects about 4—5 centimetres at each side. It is
fitted at both ends with perforated India-rubber stoppers, and
is packed for about two-thirds of its length with granular
cupric oxide, the column of this oxide extending from a little
way in front of the middle of the tube to close to the further
off end. Prior to carrying out a combustion, the tube with
its contents is heated red-hot in the furnace and a current of
dried and purified air or oxygen is passed through it, so as to
effect the removal of all traces of organic matter from it and
from the cupric oxide which it contains. The burners which
heat the front (or inlet) portion of the tube are then turned
out, and the front half of the tube (embracing the portion
which is not packed with cupric oxide) is permitted to cool,
without intermission of the air current, while the cupric oxide
is maintained at a red heat. The weighed tubes in which
O72 GRAVIMETRIC ANALYSIS.
the water and the carbonic anhydride are to be separately
collected are next attached to the outlet end of the combus-
tion-tube. The water is collected in a small U-tube packed
Fic. 84
Calcium chloride tube and potash-bulbs.
with fragments of calcium chloride, or of pumice-stone
moistened with concentrated sulphuric acid (Fig. 84) ; the
carbonic anhydride in a series of bulbs (Fig. 84) containing
solution of potassium hydroxide (sp. gr. about 1.27). The
calcium chloride tube is fitted to the combustion-tube by means
of the perforated India-rubber stop-
per at the outlet end, and the
ash-bulbs are attached to the
calcium chloride tube by a short
piece of India-rubber tubing. The
potash-bulbs must carry a short
light tube containing a column of
small fragments of potassium
hydroxide three or four centimetres
long: this serves to arrest the
small quantity of moisture which is
carrried away from the solution of
potash by the dried air which passes through it during the
operation. The form of potash-bulbs illustrated in Fig. 84
is that originally introduced by Liebig, but it has now been
almost entirely superseded by improved forms, Fig. 85
represents one of t he commoner forms now in use, ‘
When the tube has heen prepared for the combustion im
the manner described, the weighed quantity (usually 0.1 to
0.2 gramme) of the substance to be burned, contained in a
porcelain or platinum “ boat,” is rapidly introduced into the
combustion-tube, the stopper at the inlet end being withdrawn
for this purpose and then replaced as soon as possible. The
substance is now gradually and cautiously heated in the
current of air, the furnace burners being lighted at successive
~
Potash-bulbs.
CARBON, HYDROGEN, OXYGEN, NITROGEN. 673
intervals of a few minutes, until, eventually, the whole length
of the combustion-tube within the furnace is red-hot. The
tube is maintained at a red heat, and the current of air (or
of oxygen, if necessary) is continued until the substance is
completely burned and the products of its combustion have
been entirely swept out of the combustion-tube and into the
absorption apparatus. The caleium chloride tube and the
potash-bulbs are detached, and set aside near the balance for
some time to cool, and are then separately weighed, The in-
crease in weight of each of the two portions of the absorption
apparatus, due to water and to carbonic anhydride respectively,
is noted, and the percentages of hydrogen, carbon, and (by
difference) oxygen are calculated.
General Manipulation for the Determination of Nitrogen.
1, Determination by Conversion into Ammonia,—The com-
bustion-tube employed in this operation is half a metre or
more in length, and is drawn out to the diameter of an
ordinary quill and closed at one end, the quilled end being
Fic, 86
about 5 centimetres long, and bent so as to form an obtuse
angle with the main portion of the tube, Two such tubes
are readily made by softening in the blowpipe-flame two or
three centimetres of the central part of a tube about a metre
long, and drawing the halves of the tube apart, as shown in
the above engraving (Mig. 86). The tubes are separated
by melting the glass in the middle of the quilled portion.
he soda-lime to be used in converting the nitrogen into am-
monia is made by slaking quicklime with a solution contain-
ing so much sodium hydroxide that about two parts of quick-
lime shall be mixed with one of sodium hydroxide, drying
the product, heating to bright redness, and finely powdering ;
it should be preserved in a well-closed bottle. Some of the
soda-lime is introduced into the tube, then layers of the weighed
substance and soda-lime, thorough mixture of these being
45
674 GRAVIMETRIC ANALYSIS,
effected by means of a long copper wire having a short helix,
a good layer of soda-lime is added, and a plug of asbestos,
Bulbs (Fig. 87), known as those of Will and Varrentrapp
(the originators of the method), containing hydrochloric acid
of about 25 percent., are then fitted by means of a cork, and
the tube is gradually heated from the outlet end, backward,
to the closed end in the furnace—to a not tov bright red heat,
or some of the produced ammonia gas may be tips a:
When gas bubbles no longer pass through the bulbs and com-
bustion is considered to be quite complete, the tube is allowed
to cool somewhat, the quill is then broken, and air is slowly
drawn through the tube and bulbs by means of an aspirator
Fig. 87
Nitrogen-bulbs.
until all ammonia.gas may be considered to have been absorbed
by the acid. The bulbs are disconnected, their contents and
rinsings poured into a small dish, solution of chloroplatinie
acid added, and the operation completed as in the determina-
tion of potassium and ammonium salts (see pp. 641 and 645).
Or the ammonia may be absorbed in a known yolume of
standard sulphuric acid, of which the residual excess is deter-
mined by means of a standard alkali; certain obvious ealeu-
lations then giving the quantity of ammonia produced.
Conversion into ammonia may also be effected by heating
the substance with the most concentrated sulphuric acid and,
if not then thoroughly attacked, with potassium permanganate
(Kjeldahl),
2. Determination as Nitrogen Gas ( Method of Dumas).—
The combustion-tube employed in making nitrogen determina-
tions by this method (which is applicable to all classes of
nitrogen compounds) is fitted in the same manner as that used
in determining carbon and hydrogen (p, 671), except that the
place of 8 to 10 centimetres of the column of cupric oxide, at
the outlet end, is taken by a tightly rolled strip of fine copper
wire-gauze which accurately fits the tube, The function of
CARBON, HYDROGEN, OXYGEN, NITROGEN. 675
this roll of metallic copper is to decompose oxides of nitrogen,
which frequently are produced during the combustion, the
oxygen combining with the copper while the nitrogen passes
on. The combustion is carried out in an atmosphere of
carbonic anhydride, and therefore the porcelain boat contain-
ing the substance to be burned is placed in position (7. ¢., in
front of the cupric oxide), while the tube is cold, and the
whole of the air contained in the tube is displaced by means
of a brisk current of pure carbonic anhydride while the cupric
oxide is being heated, but before the heating of the substance
is begun. When the air has been displaced, the narrow
delivery-tube which is fitted into the stopper at the outlet end
of the combustion-tube is connected with a nitrometer charged
with a concentrated solution of potassium hydroxide. As soon
as the cupric oxide and roll of copper gauze are distinctly
red-hot, the substance is slowly and cautiously heated, as in
the case of a carbon and hydrogen combustion, the whole of
the tube within the furnace being raised, eventually, to a
moderate red heat. <A very slow current of carbonic anhydride
is sometimes passed through the tube during the whole com-
bustion. In the case of substances containing a large propor-
tion of carbon, such as alkaloids, it is usually necessary to mix
the portion taken for analysis with some finely granular cupric
oxide in the porcelain boat, so as to ensure its complete com-
bustion and the evolution of the whole of its nitrogen. When
the substance is completely burned, the products of the com-
bustion are slowly driven forward into the nitrometer by
passing a moderate current of carbonic caer pe for some
time. The carbonic anhydride is absorbed and the water
vapor is condensed by the potassium hydroxide solution in the
nitrometer, and the nitrogen is collected in a pure state. The
volume of the gas and the temperature and pressure at which
it was measured are noted and, from the corrected volume, the
weight of the nitrogen and the percentage of it present in the
substance, are ascertained by making a few simple calculations,
Liquids are analyzed by methods similar to those adopted
for solids, volatile liquids being enclosed in small bulbs blown
on the end of two-inch capillary tubes. These are weighed
previously to and after the introduction of the liquid, the end
of each capillary tube being sealed prior to the second weigh-
ing; just before being placed in a porcelain boat and intro-
duced into the combustion-tube, the capillary tube is broken.
676 GRAVIMETRIC ANALYSIS.
Limit of Experimental Errors.—Two determinations of carbon
may vary to the extent of 0.1 percent. ; of hydrogen, 0.2; of
nitrogen, 0.3,
Chlorine, Bromine, or Jodine, contained in an organic substance,
may be determined by heating with fuming nitric acid and silver
nitrate in a sealed tube, or by heating to redness a given weight
of the material with ten times as much pure lime in a combustion-
tube. By the latter process, calcium chloride, bromide, or iodide
is produced, While still hot, the tube is plunged into water, the
mixture of broken glass and powder treated with dilute nitric acid
in very slight excess ; the filtered liquid precipitated by the addi-
tion of excess of silver nitrate, and the silver chloride, bromide,
or iodide collected, washed, dried, cooled, and weighed.
Sulphur, Phosphorus, and Arsenic in organic salts may be deter-
mined by heating with fuming nitric acid in a sealed tube, or by
gradually heating in a combustion-tube 1 part of the substance
with a mixture of 10 parts of nitre, 2 of dried sodium carbonate
(in order to moderate deflagration), and 20 of sodium chloride,
The product is dissolved in water, acidulated by the addition of
excess of nitric acid, the sulphuric radical precipitated, and
weighed as barium sulphate, the phosphoric and arsenic radicals
13 ammonium magnesium phosphate and ammonium magnesium
arsenate respectively,
SUGAR,
The qualitative test for sugar, by means of an alkaline
cupric solution, may be applied in the determination of sugar
in saccharine substances.
Process.—34.65 grammes of pure dry erystals of ordinary
cupric sulphate are dissolved’ in about 250 Ce. of distilled
water. 173 grammes of pure crystals of potassium sodium
tartrate are dissolved in 480 Ce. of solution of sodium
hydroxide of sp, gr. 1.14. The solutions are only mixed when
required, water being then added to form 1 litre: smaller
quantities of the fluids heing proportionately diluted. 100 Ce.
of this mixture represent 3.465 grammes of cupric sulphate,
and correspond to 0.500 gramme of pure anhydrous grape-
sugar, 0.475 of cane-sugar, 0.807 of maltose, or 0.450 of
starch, — The solutions must be preserved in well-sto
bottles to prevent absorption of earbonie anhydride, and should
be kept ina dark place. Should the mixture give a preci pi-
tate on boiling, a few drops of sodium hydroxide solution may
be added when making experiments. Such a reagent is known
as Fehling’s solution,
DETERMINATION OF SUGAR. 677
Dissolve 0.475 grm, of pure powdered cane-sugar in about
50 Ce. of water, convert into inverted sugar by acidulating
with sulphuric acid and heating for an hour or two on a water-
bath, make slightly alkaline with sodium carbonate, and dilute
to 100 Ce. Place 10 Ce. of the cupric solution in a small
flask, dilute with three or four times its volume of water, and
gently boil. Into the boiling liquid drop the solution of sugar
from a burette, 1 cubic centimetre, or less, at a time, until,
after standing for the precipitate to subside, the supernatant
liquid has just lost its blue color; 10 Ce. of the solution of
sugar should be required to produce this effect—equivalent to
0.0475 of cane-sugar, 0.0807 of maltose, or 0.0500 of grape-
sugar. Experiments on pure cane-sugar must be practised
until accuracy is attained; syrups, diabetic urine, and sac-
charated substances containing unknown quantities of sugar
may then be analyzed.
Starch is converted into grape-sugar by gentle ebullition
with dilute acid for eight or ten hours, the solution being
finally diluted so that sugar corresponding to one part of starch
shall be contained in about 150 of water.
If, instead of Fehling’s solution, Pavy’s ammoniated solu-
tion be used ( Proceedings of the Royal Society, vol. xxviii., p.
260; and vol. xxix., p. 272; or Lancet, March 1, 1884, p,
376; or Pharmaceutical Journal, 3 ser., vol. xvii, p. 856),
one-fifth more of the cupric salt will be required for the same
quantity of sugar.
In cases in which loss of blue color cannot be relied on as
indicating the termination of the reaction, the cuprous oxide
should be rapidly filtered out, washed, dried, and ignited, the
filter being ignited separately, to minimize the risk of redue-
tion, and its ash added, and the resulting black cupric oxide
weighed, When the highest attainable degree of accuracy is
required, it is now customary to determine the quantity of
copper contained in the precipitated cuprous oxide by depos-
iting it electrolytically and weighing it. One gramme of
cupric oxide (or of cuprous oxide or of metallic copper) indi-
cates the subjoined amounts of the respective sugars.
(Cane- Milk- Malt-
One gramme of Glocose, sugwr. cue. xUugur.
Cupric oxide... .. . 4535 — 4308 — 6153 — .7514
Cuprons oxide ~ 2 » 2 « . 042 — 47900 — .6543 — .81382
Metallic copper... . . 5634 — 53805 — .7707 — .0089
678 QUANTITATIVE ANALYSIS.
Sugar may be estimated roughly by the measurement of
the carbonic anhydride evolved, or of the aleohol produced,
during fermentation with yeast. In the method of Einhorn,
a measured quantity of urine is shaken up with purified yeast
and the mixture is introduced into a tube shaped like the
Doremus Ureometer, figured on p. 579, which is then allowed
to stand at the ordinary temperature for twenty-four hours.
From the yolume of carbonic anhydride evolved during the
fermentation the quantity of sugar is caleulated, or the tube
may be so graduated as to indicate the percentage of sugar in
the urine. Should the urine contain more than 1 percent. of
sugar, it must be diluted and the experiment repeated.
Saccharimetry.— A generic term for certain quantitative
operations, undertaken with the view of ascertaining the
quantity of sugar present in any matter in which it may be
contained,
Saccharimetry is frequently performed upon common
syrup (Syrupus, U. S. P.), and solutions which are known to
contain nothing but ordinary cane-sugar, -the object being
merely to ascertain the quantity present. In such a ease, it is
only necessary to take the specifie gravity of the liquid at
60° F, (15.5° C.), and then refer to a previously prepared
Table of densities and percentages.
Specific Cane-sugar, Specific Canc-sngar, Specific =
gravity. percent. gravity. percent. gravity, percent.
1.8 100 . 23.7 1.210
5.6 108 . 254 1.221
4.6 1 _ Seek 1.231
‘| 1235 . 20.0 1.242
0,0 134 , 309 1.252
10.9 143 . 328 1.261
12.8 A! . O46 1,275
14.7 J6l . 86.4 1.286
16.3 ' , 384 1.298 .
18,1 L180). 40.1 1.309 .
19.9 190 , 42.0 1.921 .
21.7 1199) 6, «43,7 1.330 .
The specific gravity may be taken by means of a hydrom-
eter, technically termed a saccharometer.
If a liquid contains other substances besides cane-sugar, the
test of specific gravity is of little or no value. Advan
may then frequently be taken of the fact that a solution of
cane-sugar causes rotation of the plane of polarization of a
ray of plane-polarized’ light to the right, to an extent propor-
DETERMINATION OF ALCOIOL, 679
tionate to the quantity of sugar in solution. The saccharine
fluid is placed in a long tube having opaque sides and trans-
parent ends; and a ray of homogeneous light, polarized by
reflection from a black-glass mirror or otherwise, is sent
through the liquid and optically examined by the aid of a
plate of tourmaline, Nicol’s prism, or other polarizing eye-
piece. Attached to the eyepiece isa short arm which traverses
a circle divided into degrees. The eyepiece and arm are
previously so adjusted that when the polarized ray is no longer
visible the arm points to the zero of the scale of degrees.
The saccharine solution, however, so rotates the plane of
polarization of the ray as again to render it visible; and the
number of degrees through which the eyepiece has to be
rotated before the ray is once more invisible is proportional
to the quantity of sugar in the solution. The value of the
degrees having been ascertained by direct experiment, and the
results tabulated, a reference to the table indicates the per-
centage of sugar in the liquid under examination. Grape-
sugar is dextro-rotatory, but Jess powerfully than cane-sugar ;
moreover, grape-sugar, unlike cane-sugar, does not suffer in-
version on the addition of hydrochloric acid to its solution—
an operation that furnishes data for ascertaining the quantities
of cane- and of grape-sugar, or of crystallizable and non-crystal-
lizable sugar, present in a mixture. In using the polariscope
in saccharimetry, it is convenient to employ tubes of uniform
size, and always to operate at the same temperature. Various
modes are adopted of applying for quantitative purposes this
action of cane-sugar and other varieties of sugar on polarized
light.
ALCOHOL.
Mulder’s process for the approximate determination of the
quantity of alcohol in wine, beers, tinctures, and other alco-
holic liquids containing vegetable matter, is as follows :—
Take the specific gravity and temperature of the liquid, and
measure off a certain quantity (100 cubic centimetres) ;
evaporate to one-half or less, avoiding ebullition in order that
particles of the material may not be carried away by the
steam. Dilute with water to the original volume, and take
the specific gravity at the same temperature as before, Of
the figures representing the latter specific gravity, all over
1.000 shows to what extent dissolved solid matter affected the
original specific gravity of the liquid. Thus, the specific
gravity ofa sample of wine at 15-5° C., is 0.9951; evaporated
680 DIALYSIS.
until all alcohol is removed, and then diluted with water to the
original volume, the specific gravity at 15.5°C. is 1.0081 ;
and 1.0081—1.000= 0.0081, which latter figure represents the
effect of the dissolved solid matter in 0.9951 part of the orig-
inal wine. 0.0081 subtracted from 0.9951 leaves 0.987, which
is the specific gravity of the alcohol and water of the wine.
Or, divide the specific gravity of the wine by the specific
gravity of the wine minus alcohol, carrying out the division
to four places of decimals ; the quotient shows the specific
gravity of the water and alcohol only of the wine. On refer-
ring to a table of the strengths of diluted alcohol of different
specific gravities, 0.987 at 15.5° C. is found to indicate a
spirit containing 8 percent. of alcohol. If the removal of the
alcohol from the wine be conducted in a retort, the liquid
being boiled and the steam carefully condensed ; and the dis-
tillate be diluted with water to the original volume of the
wine operated on, the resulting mixture will furnish a liquid
which still more accurately represents the original wine in the
propertion of alcohol’ which it contains. The number in the
table corresponding to the specific gravity of this liquid then
shows the percentage of alcohol present in the wine.
DIALYSIS.
Dialysis (from 4:4, dia, through, and dvers, lusis, a loosing or
resolving) is a term applied by Graham to a process of anal-
ysis by diffusion through a porous septum. The apparatus
used in the process is called a dialyzer, and is constructed and
employed in the following manner: The most convenient
septum is the commercial article known as parchment paper,
made by immersing unsized paper for a short time in sul-
phuric acid and then thoroughly washing it in water. A
piece of this material] is stretched over a gutta percha hoop,
and secured by a second external hoop. Dialyzers of useful
size are one or two inches deep and five to ten inches wide.
Liguids to be dialvzed are poured into the dialyzer, which
is then floated in a flat dish containing distilled water. The
portion passing through the septum is termed the diffusate,
the portion which does not pass through is termed the dialy-
sate,
The practical value of dialysis depends upon the fact that
certain substances diffuse through a given porous septum far
more rapidly than others. Uncrystallizable substances diffuse
.
CONCLUSION. 681
very slowly. Of such substances as starch, gum, albumin and
gelatin, the last named is one of those which diffuse most
slowly ; hence substances of this class are termed colloids, or
bodies like collin, which is the soluble form of gelatin. Sub-
stances which diffuse rapidly are mostly crystalline ; hence
bodies of this class are termed erystalloids.
By the aid of dialysis it is possible to separate small quanti-
‘ties of crystalloid substances from the large quantities of
colloid matter often present in vegetable and animal liquids.
QUESTIONS AND EXERCISES.
Write a few paragraphs descriptive of the process of ultimate organic
analysis.—In what forms are carbon, hydrogen, and nitrogen weighed in
quantitative organic analysis?—In the combustion of 0.41 gramme of
sugar, what weights of products will be obtained? Ans., 0.632 gramme
of carbonic anhydride (CO,) and 0.237 gramme of water (H,O).—Mention
the operations necessary for the determination of the proportion of sugar
in saccharated iron carbonate, or in a specimen of diabetic urine.— What
is understood by saccharimetry ?—Give two processes for the estimation of
the percentage of alcohol in tinctures, wines, or beer.—Define dialysis.
—- » ___
CONCLUSION.
Detailed instructions for the quantitative analysis of pot-
able water, articles of food, general technical products, special
minerals, soils, manures, air, illuminating agents (including
solid fats, oils, spirits, petroleum, and gas), dyes, and tanning
materials, would scarcely be in place in this volume. 7
The course through which the reader has been conducted
will, it is hoped, have taught him the principles of the science
of chemistry, and have given him special knowledge concern-
ing the applications of that science to medicine and pharmacy,
as well as have imparted sufficient manipulative skill to meet
the requirements of manufacture or analysis. The author
would venture to suggest that this knowledge be utilized, not
only in the way of personal advantage, but in experimental
researches on chemical subjects connected with pharmacognosy,
pharmacology, therapeutics, and pharmacy. The discovery
and publication of a new truth, great or small, is the best
means whereby to aid in advancing the calling in which we
may be engaged, increase our own reputation, and contribute
to that “ultimate end of knowledge” which Bacen. described
as “employing the Divine gift of reason to the use and bene-
fit of mankind.”
682
NAMES.
Barium
Bismuth . .......
Boron .........
Chromium
Columbium (Niobiunr)
Copper... 6. we.
Edam. 82" oe
Fluorine ........
Gadolinium... ...~
Gallium
Germanium
Helium
Hydrogen
Indium
Iridium
Lead
Lithium
Magnesium
Manganese
Nitrogen) 6.04 Be we ek
Osmiu im
Chlorine . ;
Cobalt 2... 0.0.0.2. ~2~.,
Glucinum (Beryllium)... .
GlOldl eg ae Go ey 6 ee AS
Iodine... . 2.
Iron. 2... .
Krypton... 2...
Lanthanum... ....
a ne, ee en ae i Sees Cy fey
a en Sa ee, ae, ney
'_ ee ee 28@ e8© «© @ @ «6
eo e ee e ee ee e@ e@© ¢
fs ee ee e@ @ e© 8 © @
* e ee ee ee e #8
- ee ee e# 8 «« e@
THE ELEMENTS.
THE ELEMENTS.
International
Atomic Weights.
THE ELEMENTS. 683
THE ELEMENTS (continued).
International
NAMES. Symbols. Atomic Weights.
H -:1 O = 16
Oxygen... ........ O 15.88 16.00
Palladium .........- Pd 105.7 106.5
Phosphorus... ...... Pp 30.77 31.0
Platinnm .....2.2.2.. Pt 193.3 194.8
Potassium... ......-- K 38.86 39.15
Praseodymium ....... Pr 139.4 140.5
Radium .......... Ra 223 225
Rhodium ......... Rh 102.2 103.0
Rubidium ......... Rb 84.8 85.4
Ruthenium. ........ Ru 100.9 101.7
Samarium .......-.. Sm 148.9 150
Scandium .......6. Se 43.8 44,1
Selenium. .........- Se 78.6 79.2
Silicon... 2... - + ee, Si 28.2 28.4
Silver... .....2.4. Ag 107.12 107.93
Sodium .......-e+.-. Na 22.88 23.05
Strontium ......... Sr 86.94 87.6
Sulphur .........-.- 8 31.83 32.06
Tantalum ......2... Ta 181.6 183
Tellurium ......-.. Te 126.6 127.6
Terblum.........-. Tb 158.8 160
Thallium .......... Tl 202.6 204.1
Thorium.........-. Th 230.8 232.5
Thulium.......... Tm 169.7 171
Mew. ee ee ew ew ew Sn 118.1 119.0
Titanium. ......... Ti 47.7 48.1
Tungsten... ....-.-. W ' 182.6 184.0
Uranium ......... U 236.7 238.5
Vanadium ........- Vv | 50.8 51.2
Xeonn........-228-. xX 127 128
Ytterblum ......... Yb 171.7 173.0
Yttrium... ..4.... Yt 88.3 89.0
Jines 2. ee | Zn | 64.9 65.4
Zirconium ......... Zr 89.9 90.6
INDE X.
Abies balaamea, 415, 478
Abrin, 501
Abrus precatorius, 501, 547
Absinthe, 496
Absinthin, 496
Absolute alcohol, 425, 595, 600
temperature, 46
Absorption spectrum, 559
Acacia, 121, 494
eatechu, 342
Acalyphine, 526
Acetal, 450
Acetaldehyde, 448
Acetamide, 408
* Acetanilide, 408
Acetanilidum, 408
Acetate, ammonium, 95, 282
amyl, 404
calcium, 281
copper, LSd
ethyl, 283, 403
ferric, 158, 284
ead, 293
mercurous, 284
morphine, 282, 514
potassium, 74
silver, 284
sodium, 87, 281
gine, 135
Acetates, 241
analytical reactions of, 283
decomposition of aqueous solu-
tions of, 282
distinction of, from meconates
and thiocyanates, 333, 345
Acetic acid, 281, 283, 448
glacial, 283
volumetric determination
of free, (22
anhydride, 282
ether, 285, 403
series of acids, 448
relations of, 455
Accto-acetic acid in urine, 551
ether, 404
Acetone, 283, 464
iD urine, 580
iodoform test for, 580
Le Nobel's test for, 580
Acetonitrates, ferric, 162
Acetonitrile, 447
Acetonum, 464
Acetophenone, 464
Avetoximes, 510
Acetphenetidin, 408
Acetphenetidinum, 408
Acetum opii, 282
scilla,
Acetyl], 282
benzaconine, 527
chloride, 282
salicylic acid, 458
Acetylene, 395
series of hydrocarbons, 394
Avcetylenes, relations to paraffins
and olefines, 394
Acetylide, copper, 395
Acetylides, 395
Acichlorides, 169, 273
Acid anhydrides, 65
character, 66
potassium sulphate, 272
tartrate, 79, 83, 305
radical, 65
radicals, qualitative detection
of, 348
quantitative determination
of salts of, 659
tables to aid in the detec-
tion of, 351, 352
reaction, 65
salts, 60, 78, 79
sodium sulphate, 253
solution of arsenic, 174
Acidimetry, 621, G24
Acidity of hases, 66
Acids, acetic series, 448
nerylic series, 455
analytical detection of, 348
benzoic or aromatic series, 456
basicity of, 66, 251
cinnamic series, 460
classes of, 65
G85
686
Acids, concentration of, 251
dibasic, 66, 461
free, determination of, 621
glyoxylic series, 455
hexabasic, 462
hydroxybenzoic series, 457
lactic series, 453
malic series, 461
of chlorine, 280
of phosphorus, 336
of sulphur, 206
organic, 446
phthalic series, 462
polybasic, 462
Properties of, 65
“strength” of, 251
strong, 251
euccinic series, 463
sulphonic, 428
table showing relations of ace-
tic, lactic, and
glyoxylic, 455
acetic and dibasic
series, 463
tartaric series, 462
tetrabasic, 462
tribasic, 462
trihydroxy benzoic series, 459
weak, 251
Acidum aceticum, 283
dilutum, 283
glactale, 283
benzoicum, 321, 456
boricum, 319
cumphoricum, 473
citricum, 308
gallicum, 343
hydriodicnm dilnutum, 260
hydrobromicum dilutum, 257
Aydrochloricum, ao, 2d
dilutum, 253
hydrocyanicum dilutum, 267
hypophosphorosum, 329
dilutum, 329
lacticum, S31
nifricum, 272
dilutum, 272
nitro-hydrochloricum, 273
dilutum, 273
oleicnm, 430
phosphoricum, 313
dilutum, 313
salicylicum, ANT
stearicum, 453
sulphoricum, 203
aromaticonm, 203
dilutum, 2S
ctlphorosum, 265
tannicum, S40
INDEX.
Acidum tartaricum, 300
trichloraceticum, 45]
Acipenser, 547
Acokanthera, 502
Aconine, 526
Aconite, 526
Aconitia, 526
Aconitic acid, 309
| Aconitina, 526
Aconitine, 526
| dconttum, 526
Jerox, 527
heterophyllum, 527
napellus, 526
Acorin, 470
Acorus calamus, 470
| Acriny] iso-thiocyanate, 427
| Acrolein, 437, 455
Acrose, 451
8-Acrose, 454
Acrylaldeh de, 437, 45
Acrylic acid, 455
Actea racemosa, 507
Adeps, 442
benzuinatus, 442
lanw, 440
hydrosus, 440
Adhatoda, 540
rasica, 540
Adraganthin, 494
Advice to students, xiii, 366
| Lyle Marmelos, 495
‘Aérated bread, 485
wiuter, 299
ZEsculin, 535
Ether, 431
aceticus, 403
Athylis carbamas, 455
chloridum, 398
Affinity, chemical, 50
| Agate, 337
Agropyrum, 507
Air, composition of, 32
guns burner, 28
influence of animals and plants
on, 25
nitrogen in, 31, $2
oxygen in, 24, 32
onmonized, 261
relative volumes of chief con-
stituents of, 32
weight of 1 cubic centimeter,
G05
of 100 cubic inches, G06
Ajownn oil, 466
Ajwain oil, 466
flowers of, 406
Ajwainka-phul, 466
Alabaster, 112
INDEX.
AlJantic weid, 468
Alantol, 468
Albumens, 546
Alfmonin, 542
detection of, in urine, 575
test solution, 542
vegetable, 46
Albuminoids, 542
Albumins, 546
Albuminuria, 576
Albumoses, 46, 49
Albumosuria, 576
Alchemy, 15
Alcohol, 419, 422
absolute, 423, 595, 600
abwolutum, 423
allyl, 426
amyl, 346, 424
varicties of, 425
benzyl, 435, 460
butyl, 347, 424
ceryl, 426
cetyl, 425
cinnamy!l, 460
decylene, 427
dilulum, 423
ethyl, 419
from sugar, 420
hydroxybenzyl, 437
in bread, 420
melissyl, 420
methyl, 418
myricy!, 426
phenic, 432
propenyl, 437
propyl, 424
purity of, 419, 424, 628
quantitative determination of,
679
salicyl, 437
tests for, 423
tolyl, 435
various strengths of, 422
Alcoholates, bromal, 453
chloral, 449, 453
Alcoholic beverages, 422
fermentation, 420
Alcoholometer, 601
Alcohols, 416
allyl series, 426
uronnetic, 492
diatomic, 417, 435
diliwdrie, 417, 435
othy! series, 417
hexahydric, 445
monatomic, 417
monohydric, 417
naphtinyl, 411
pentahydrie, 445
687
Alcohols, polyhydric, 445
primary, 417
general method of prepar-
ing, 417
secondary, 417
tertiary, 417
tetruhydric, 445
triatomic, 437
trihydric, 437, 445
| Aldehyde, 446, 448
acrylic, 437
-ammonia, 449
benzoic, 322, 409, 435, 456, 407
cinnamic, 460, 467
cominic, 468
enodic, 470
formic, 200, 448
glycollic, 446
heptoic, 468
lauric, 470
methy|protocatechuic, 459
orthohydroxy benzoic, 448
oxalic, 446
parahydroxybenzoic, 458
protocatechuic, 458
salicylic, 437, 458
test for, 449
| Aldehydes, 446
general formation, 446
reactions, 447
Aldoses, 451
Aldoximes, 510
Ale, 422
Alexandria senna, 498
Aliphatic compounds, 374
Alizarate, potassium, 411
Alivarin, 411, 552
Alkalies, 64
analytical separation of the,
LOG
quantitative determination of
the, 614
Alkalimetry, 620
Alkaline carbonates, volumetric
determination of the, 618
earths, 129
reaction, (4
solution of arsenic, 174
Alkaloids, 508
animal, 510
antidotes to the, 513
constitution, O08
nomenclature of, 513
poisonous, oxamination for, h5b,
el seq.
plant, S10
reagents for, 570
Alkanet, 552
Alkanna tinctoria, 552
hd
G88
Alkannin, 552
Alkyl salts, 447
Allotropic substances, 285
Allotropy, 285
Alloxan, 346
Alloy, 209
Allyl alcohol, 426
cyanide, 427
iso-thiocyanate, 427
propy! disulphide, 427
series of nlcohols, 426
thiocyanate (iso-), 427
Allylene, 394
Almond oil, 444
Almonds, oil of bitter, 322, 435, 456, |
466, 497
test for nitrobenzene in,
408
water of bitter, 268
Aloe, 413
purificata, 413
Aloes, 415
purified, 413
Aloins, 413
formule of, 414
Aloimum, 413
Alpha-naphthol, 411
Alstonia constricla, 534
scholaria, 534
Alstonicine, 534
Alstonine, 534
Althea, 494
Alum, 146
ammonia, 147
cake, 147
chrome-, 147, 168
dried, 147
flour, 140
iron-, 147
potash-, 147
roche or rock, 147
root, 344
shale, 146
sodium, 146
Alumen, 146
exsiccatum, 147
Alumina, see Aluminium oxide,
Alumint hydroridum, 148
sulphas, 147
Aluminium, 146
acetate, 145
analytical reactions of, 148
and ammonium sulphate, 146
and potassium sulphate, 144
aud sodium, double chloride,
146,
INDEX,
Aluminium, detection of, in pres-
ence of iron and chromium,
107, 171
hydroxide, 148
oxide, 146, 147
quautitative determination of
649
separation of, from chromium
aud iron, 170, 171
silicate, 146, 337
steel, 146
sulphate, 147
Alums, 146
Amalyam, 209
ammonium, §4
electric, 200
sodium, 94
tin, 195
Amalgamation, gold, 197
Amber, 339
oil of, 339
American pennyroyal, 469
turpentine, 415
wormseed, 471
Amethyst, 146
| Amianth, 337
Amides, 408
Amido-acetic acid, 550
Amido-acet-phenetidin, 408
| Amido-benzene, 511
Amido-succinamic acid, 461
Amines, 408, 508
analogues of, 500
constitution of, 408
Amino-bases, 409
Ammonia, 93, t4
acetate,
henzoate,
Old names for
ammoninm salts,
carbonates, :
citrate, which see.
detected by Nessler’s test, 616
gus, composition of, 05
in drinking water, 616
nitrate, Old names for
oxalate, anmoninm salts,
phosphate, ! which see.
preparation of, 4
solution of, 95
sulphate, see Ammonium salts
volcanic, 94
volumetric determination of
solutions of, 615
water, 4
Ammoninaeal liquor, #4
salts, sources of, 93
| Ammoniacam, 479
fl woride, 146 | Ammonia spiritua aromations, 07
bronze, 146 | Ammoniated mereury, 218
chloride, 146 | varieties of, 218
INDEX.
, Ammonii acetatis liquor, 06
henzoas, 08, S22
bromidum, 98, 257
carbonas, 96
chloridum, $4
iodidum, 98
valeras, 347
Ammonio-chloride, mereury, 218
-citrate, iron, 159
sulphate, magnesium, 667
tartrate, iron, 161
Ammonium, 93
acetate, 15, 282
aluminium sulphate, 146
amalgam, {4
ausalytical reactions of, 102
aud bismuth, citrate, 230
arsenate, 175
aspartate, 332
benzoate, 08, 322
bicarbonate, 96
bromide, $8, 257
carbamate, 16
carbonate, 26
commercial, 96
test solution, 97
chloride, 93
chloroplatinate, 102, 201
citrate, 93
cyanate, 324
derivation of word, 37
dichromate, 107
ferric sulphate, 147
ferrous sulphate, 151
fluoride, 328
formate, 265
hydrosulphide, 99, 287
hydroxide, 4
hypophosphite, 329
magnesium arsenate, 1°27
phosphate, 126, 315
sulphate, G47
molybdate, 316
nitrate, 97, 271, 273
nitrite, S44
oxalate, 18
test solution, 09
persalphate, 29
phosphate, 98
potassinm, sodium, and lith-
ium. separation of, 106.
quantitative determination of,
644
salts, souree of, 13
volatility of, 102
succinate, 332
sulphate, 4
sulphide, 90
test solution, 99
44
6381)
Ammonium, urate, 316
valerate, 347
volumetric determination of
carbonate of, 617
Amomum melequeta, 469
Amorphous carbon, 207
cinchona alkuloid, 522
meaning of, 52
phosphorus, 313
sulphur, 285
Amphicreatinine, 510
Amrad, 494
Amygdala amara, 444, 497
duleis, 444, 497
Amygdalin, 497
Amyl, acetate, 404
alcohols, 346, 424
nitrite, 334, 405
valerate, 347, 405
Amylene, 392
hydrate, 425
Amylis nitris, $35, 405
Amyloids, 487
Amylolytic enzyme, 549
Amylopsin, 549
Amyloses, 457
Amylum, 487
Amyric acid, 478
|} Amyrin, 478
Avacyclus pyrethrum, 476
Analogies between chlorine, bro-
mine, and iodine, 204
Analogy of carbon and silicon, 339
ofsodiumand potassiumealts, {2
of nitrogen, phosphorus, arsenic
and antimony, 122, 317, 509
| Analysis, blowpipe, 355, 354
gas, 44, 558
gravimetric, 610, 638
meaning of word, 50
of insoluble substances, 360,
rt seq.
of medicines, 558
of salts, 354
of substances having unknown
properties, 556
organic (qualitative), 370
proximate, 670
quantitative, 609
spectrum, 250, 550
systematic, for the detection
and separation of the metals,
105, 106, 127, 144, 170, 202,
239, 242
ultimate, 670
volumetric, 610, 611
Analytical detection of the acid
rulicals of salis soluble in water,
a8
690
Analytical memoranda, 246
Anamirta paniculata, W2
Aunmirtin, 503
Anchusa tinctori a, SOL
Anchusin, 552
Andrographia, 507
caules et radix, 507
paniculata, HOT
Andrupogon citratus, 471
nardus, 468
schananthus, 49
Anemone, 469
Anemonic acid, 469
Anemonin, 469
Aneroid barometer, 45
Anethol, 466
Angelate, potassium, 466
Angelic acid, 464
powder, 187
Angelica, 479
Angostura bark, fulse, 524
true, bd4
Angosturin, 534
Anhydride, acetic, 252
antimonic, 158
arsenic, 176
arsenous, 173, 174
boric, 318
carbonic, 298
chlorochromic, 169, 263
chromic, 166, 165, 263
molybdic, 316
nitric, oF;
nitrous, 274, 2
persulphurie, Qs
phosphoric, 31, S13, 333
plithalice, 411, 462
silicic, 338, 339
stannic, 194
sulphocarbonic, 402
sulphuric, 291, 285
sulphurous, 215, 285, 258
thiocarbonie, 302
Anhydrides, 90, 282
Anhvydrochromate,
silver, 23=
Anhydrochromic acid, 167, 165
Anhydro-ecgonine, 525
Anhydrosulphites, 269
Anhydrous arsenous acid, 174
chromic acid, 166, 168
cupric sulphate, 206.
ferrie chloride, 155
ferrous ch loride, 156
salts, 90
stannic sulphide, 196
Aniline, 407, 511
blue, GBS
colors. me
potassium, 167
INDEX,
Aniline green, 555
red, 555
yellow, 555
| Animal alkaloids, 410
charcoal, 207
decolorizing power of, 298
purified, 207
rouge, 023, 653
starch, 491
Animals wud plants, complementary
action of air, 24
Anise-fruit, 466 :
-oil, 466
Annatte, 552
Anode, 68
| Anodyne, Hoffinann's, 432
Anogeiaxus latifolia, 494
Anthemen, 466
Anthemis, 466, 507
nobilis, 466
Anthion, 206
Authracene, 411, 552
Anthracite, 193
Anthraquinone, 411
Antichlor, 289
Antidotes to alkaloids, 513
antimony, 12
arsenic, 158, 1&5
harium, 111
carbolic acid, 434
copper, 208
cyanides, 2700 |
hydrochloric acid, 255
hydroeyanio acid, 270
lead, 226
mereury, 221
nitric acid, 276
oxalic acid, 304
prussic acid, 270
salt of sorrel, 504
silver, 238
sulphuric acid, 204
tin, 197
zine, 137
Antifebrin, 408
| Antimonial poisoning, antidotes,
192
wine, 188
Antimonic anhydride, 158
chloride, LST
oxide, 158
sulphide, 1&0
Antimowti et potasa tartraa, 188
Antimonious chloride, 186
oxide, 123, 187
oxychloride, 187, 19]
sults, analytical reactions of,
1h)
sulphide, 156, 189, 190,203 ef aeg,
INDEX.
Autimonium et potassii tartras, 188
quantitative determination
of antimony in, 652
Antimoniuretted hydrogen, 11
Antimony, 172, 156
Aqua amygdale amarx, 497
anixi, 465
aurantii florum, 465, 467
Sortior, 407
camphor, 472
analytical reactions of, 190
and potassium tartrate, 158
and tin, separation of, 197
antidotes to, 192
chloreformi, 400
cinnamomi, 465
ereosoti, 434
destillata, 131
Joniculi, 465
fortis, 273
duplex, 273
simplex, 273
hamamelidis, S07
hydrogenii dioridi, 109
menthw piperite, 465
viridis, 465
regia, 203, 273
rose, 465, 409
fortior, 470
Arabic acid, 494
Arabin, 121, 404
Arabinose, 441
Arachidic acid, 455
Arachin, 444 :
arsenic and tin, analytical sep-—
aration, 202, et seq
black, 186
purified, 186
bromide, L&6
butter of, 187
chloride, 186
solution, 186
crocus, LAG
crude, 186
derivation of word, 37
from arsenic, to distinguish,
190, ef seqg., 202
glass, LA6
hydride, 191, 204
in organic mixtures, detection ‘|
of, 561 Arachis, 444
iodide, 186 hypogiea, 444
Marsh’s test for, 191, 204 oil, 444
oxides, 187 Arbor Dianw, 238
oxychloride, 187, 191 Arbutin, 342, 498
oxysulphides, 180 Archil, 554
pentachloride, 187 | Aretium oy gad
quantitative determination of, | Arctostaphylos, wea urei, 498
630, 652 Are, 41
sulphide, 186, 189, 190, 203 Areca catechn, 342
sulphur salts of, 189 nuts, 342
sulphurated, 189 Arecaine, 345
tannate, 342 Arecoline, +42
tartarated, 188 Arckane, 342
tetroxide, 188 Areometers, 601
volumetric determination, 630 | Argal, 305
Antimonyl, 184 Argent-ammonium-nitrate, 236
Antipyrin, 408 Argenti cyanidum, 237, 268
Antipyrina, 408 nitras, 235
Antiseptic, 319, 434, 437, 457 Susus, 235
Apatite, 315 mifigatua, 236
Apocynum, 507 oxidum, 206
Apomorphine hydrochloridum, 517 Argentic chloride, sulphide, ete.,
Apomorphine, 516, H41 see Silver Salts.
Aporetin, 412 | Argentiferous galena, 233
Apparatus, xiv, xv, 10 Argentum, 30
for experiments, xiv Argol, 306
for volumetric analysis, 612 Argon, 32, 33, 37
lists of, xiv Aristolochia, 527
Apple-essence, 405 reticulata, 527
oil, 406° werpentaria H27
wine, 422 Aristolochin, 527
Aqnue ammonia, 05 | Aristolochine, 527
fortior, 05 Armenian bole, 562
692
Arnatto, 552
Arnica, 474
Arnicin, 474
Arnotto, 552
Aromatic alcohols, 432
compounds, 374
glyculs, 456
series of hydrocarbons, 406
sulphuric acid, 293
Arrhenal, 323
Arrowroot-starch, 490 (fig.)
Arsenate, ammonium, 175
magnesium, 127
barium, 185
calcium, 185
vopper, 184, 208
iron, 176, 155
silver, 184, 237
sodium, 176
methy!, 323
volumetric
of, 629
zine, LSd
Arsenates, 175, 317
Arsent iodulum, 173
trioridum, 173
Arsenic, 37, 172, 173,174
acid, 175
analytical reactions of, 177
and arsenical solutions, volu-
metric determination of ofli-
cial, 629
and phosphorus, similarity of
compounds, 176
anhydride, 176
antidotes, 158, 185
antimony, and tin, analytical
separation of, 202, et seq
arsenous and arsenic com-
pounds, 175, 182, 185, 185
Berzelius’s test for, 177
Bettendorff's test for, ]82
derivation of word, 37
detection of, in metallic copper,
17
in organic mixtures, 561
Fleitmann's test for, 181
from antimony, to distingnish,
190, et seg., 202
Gutzeit’s test for, 182
hydride, 204 — =
Marsh's test for, 179, 204
molecular weight of, 173
odor of, 175
quantitative determination of,
650
red native sulphide, 173
reduction of arsenic to arsenonus
compounds, 175, 184, 155
determination
INDEX,
Arsenic, Reinsch's test for, 178
sources of, 173
se“ ele 174, 153, 190, ef seq.,
trioxide, 173
white, 173
acid solution of, 174
alkaline solution of, 174
yellow native sulphide, 173
Arsenical ores, 173
poisoning, antidote, 183
sulphur, 183
| Arsenide of cobalt, 141
hyd n, 180
raroge
| Arsenio-sulphide, cobalt, 141
iron, 173
nickel, 143
Arsenite, cupric, 184, 208
potassium, 174
silver, 184
sodium, 174, 175
| Arsenites, 174
Arseninretted hydrogen, 150, 204
| Arsines, 500
; Arsenous acid, 173, 174
anhydride, 173, 174, 178
chloride, 179
iodide, 173
oxide, 173
sulphide, 183, 192, 202, ef seg,
Art of chemistry, 18
Artemisia absinthium, 496
maritima, 471
pauciflora, 504
Artificial alkaloids, 511-513
| Asafetida, 479
Asafutida, 479
Axagrva officinalis, 40
Asbestos, 337
platinized, 292
Aseidia, 496
Asclepedin, 507
Aselepias tuberosa, 507
Aselline, 443
Aseptol, 429
Ash, 107
black-, 89
bone-, 117
soda-, 90
Asparagin, 332, 461
Aspartate, ammonium, 332
Asphalte, 478
Aspidinol, 444
Aspirlium, 444
Aspidospermine, 527
Aspirin, 4538 a
Asymmetric car atoms, S06
-ate, meaning of, 77, 8
Atees, 527
INDEX.
Ateesine, 527
Atis, 527
Atmosphere, aqueous vapor in, 32
carbonic anbydride in, 32, 298 |
Bal
composition of, 32
mivor constituents, 32
nitrogen in, 31, 32
oxygen in, 24, 32
ozone in, 261
Atmospheric pressure,
ment. of, 44
Atomic heat, 58
proportions, 53, 210
symbols, 69
theory, 52
weights, 52, 55, 682
as indicated by densities of
gases and vapors, 56,
et 8eq.
specific heats, 58
Atomicity, 63 .
Atoms, 52, et seq.
conception of, 52
linkage, 375, 410
nascent, 69
quantivalence of, 68
Atropa belladonna, 527
Atropia, 527
Atropina, 527
Atropine sulphas, 529
Atropine, 511, 527, 541
acid inalate, 527
sulphate, 527
synthesis, 528
Attar of rose, 469
Aurantti amari cortez, 507
Auri et sodii chloridum, 198
Auric chloride, 198
solution of, 198
Auripigmentum, 173
Aurous-auric sulphide, 198
Aurum, 38
Australian kino, 342
Avignon grains, 551
Avogadro's Hypothesis, 53
Azadirach, Indian, 507
Azadirachta Indica, 7
Azobenzene, 4038
Azoimide, 510
Azoxybenzene, 408
measure-
BaBOUL, 343
Bacillus acidi lactict, 331
Bacteria, 421
Bacterium mycodermit, 281
Buel fruit, 495
mucilage, 495
Bahia powder, 412
Bakas, 540
693
| Baking-powder, 485
Balance, 598
Balloons, coal-gas for, 29
hydrogen for, 20
mn-of-Giilead fir, 478
Balsam, Canada, 415, 478
copaiba, 477
Gurjun, 477
of Peru, 323, 460, 474
of tolu, 323, 460, 474
Balsams, 474
Balsamum perurianum, 460, 474
tolutanum, 460, 474
Baphia nitida, 552
Baptin, 529
Baptisia tinctoria, 529
Baptisin, 529
Baptitoxine, 529
Bar (wrought) iron, 150
Barbados aloes, 413
Barbaloin, 413
Baric chloride, nitrate, etc., see
Barium.
Barium, 109
analytical reactions of, 110
antidotes to, 111
arsenate, 185
dichromate, 169
carbonate, 110
native, 109
chloride, 109
test solution, 100
chromate, 110, 169
derivation of word, 38
detection of, in presence of
strontium, calcium, and mag-
nesium, 128
dioxide, 109
flame, 110
hydrogen phosphate, 110, 317
hydroxide, 109
hypophosphite, 329
nitrate, 109
oxalate, 110
oxide, 109
persulphate, 295
phenolsulphonate, 435
phosphate, 317
quantitative determination of,
645
salts, antidotes to, 111
strontium and calcium, separa-
tion of, from magnesium, 128
sulphate, 109, 110, 290, 293
sulphide, 109
sulphite, 290
tungstate, 555
Barley, husked, 488
pearl, 488
694 INDEX,
Barley starch, 488, 490 ( fig.) Benzene, tri-derivatives of, 410
sugar, 450
Barometer, 45
Barwood, 470, 552
Baryta, 100
-water, 109
Basalt, 146
Bases, acidity of, 66
classes of, 64
organic, 508
properties of, 64
Basic character, G6
salts, 66
Basicity of acids, 66, 251
Bassorin, 121, 494
Bastard saffron, 553
Benzin, S87, 406
Beuzine Collas, 467
Benzinum, 387
prrificatum, 387
Benzoate, ammonium, 98, 322
ferric, #22
lithium, 323
sodium, 322
Benzoates, 321
tests for, 323
| Benzodichloride, $24
Benzoie acid, 322, 435, 456
Benzoin, $22, 325, 474
Siam, 459
Benzoinated lard, 442
Bate brick, 337
Bauxite, 146
Ray oil, 469
-salt, 86
Bayberry oil, 469
Bean, Calabar, 537
St. [guatins’s, 425
Tonka, 461
Beane's ozone generator, 261
Bearberry, 342, 498
Beaver-tree, 507
Bebeeru bark, 520
Benzoinum, 321, 474
Benzole, 406
Benzolin, 387
Benzonulphinide, 425
Benzosulphinidum, 425
Bensxotrichloride, 400
Benzoy! chloride, 456
ecgonine, 632
methyl ecgonine, 532
pseudo-tropeine, 532
sulphonic imide, 429
| Benzyl alcohol, 4%, 460
» wood, 529 benzoate, 321, 460
Beberine, 529 chloride, 409
sulphate, 529 cinnamate, 460
Bebirine, 529 Benzylidene chloride, 409
Beer, 422, 493 Berbamine, 530
Beeswax, 426 Berberine, 530
Beetroot, 444 acid sulphate, 530
Behenic mag 455 periodide, 530
Belladonna, 5 a7, 535 Berberis vulgaria, 530
Japanese, 520 Bergamot juice, 308
Relladonne folia, 527 oil, 466
vadiz, 527 Bergapten, 467
Bell-metal, 193 Berlin blue, 554
Bend glass tubes, to, 21 red, Aie@
Beuné oil, 444 Berzelius'’s tube, 177
Benzaconine, 527 Beryllium, see Glucinum,
Kenzaldehyde, 322, 435, 456 Bessemer steel, 150
eyanhydrin, 497 Betaine, 511
Benzaldehydum, 456 Betanaphthol, 411
Benzene, 322, 406 Betel, 343
addition compounds, 411 Bettendortf’s test for arsenic, 182
di-derivatives of, 410 Betula lenta, 458
formation from acetylene, 396 | Bhang, 475
formula for, 410 Bi-, the prefix, 77
hexachloride, 410 . Bibasic, see Dibasic.
meta- disulphonic acid, 436 Biberine, 528
mono-derivatives of, 410 | Bibiru bark, 520
ring, 409, 436 | Biborate sodium, 318
series of hydrocarbons, 406 Bibulous paper, 116
const itution of, 400 Bica rbonate Ammeninm, G
sulphonic acid, 494, 442 | caleiuns, SOL
INDEX. 695
Bicarbonate, potassium, 76 Bitter almonds, cassava, 458
sodium, 57 “sweet, 5345
chemically pure, 614 wine of iron, 161
lozenges, 89 | Bittern, 255
Biehloride, mercury, 214 | Rituminous coal, 193
Bikh, 527 Biuret reaction, 576
Bile, 549 Bivalence, 63
detection of, in urine, 577 Bivalent radicals, 63
tests for presence of, 550 Bira orellana, 552
Biliary ecalenli, 501 Bixin, 552
Bimeconate, morphine, 514 Black alder bark, 412
Bioses, 481, 484 «antimony, 156
Birch oil, 458, 466 -ash, 89
Bish, 527 lr | -hand ironstone, 149
Bismuth, 227 hone-, 207, 555
analytical reactions of, 231 cherry bark, 498
and ammonium citrate, 240 cohosh, 507
and potassium iodide, 570 | coloring matters, 555
bromide, 229 “drop,” 282
carbonate, 230 | dyes, 555
citrate, 230 flux, 175
derivation of word, 38 | haw, 507
glance, 227 , hellebore, 501
hydroxide, 231 ink, 165, 505
hydroxynitrate, 229 ivory, 555
iodide, 220 lamp-, 207, 555
nitrate, 228 -lead, 36, 298, 555
ochre, 2 227 | mustard, 427
oxide, 227, 229 | oxide, copper, 206
oxyuitrate, 228, 555 iron, 150
oxysalts, 225 minganeses, 138
quantitative determination of, mercury, 217
ie | pepper, 548
of bismuth in, 763 platinum, 200
salts, composition of, 220, 230 shake-root, HOT
test for calcium phosphate sulphur, 285
in, 231 Blackberry, high, 343
snbcarbonate or oxycarbonate, | Bladder, green, 554
228, 230 Blane de Perle, 220
subgallate, 230 Blast furnace, 14%
subnitrate, 225 Blwud’s pill, 153
subsalicy late, D0 - Bleaching by chlorine, 35, ae,
sulphate, 225 -liquor, 120
sulphide, 227, 231 -powder, 119
Bismuthi citras, 2350 salts, 277
et ommonti cifras, 230 | Blende, 191
suboarbonas, 240) Block tin, 198
subgattas, 251 Blood, M44
subnitras, 228 | absorption spectrum, 559
wubwalioylas, 230 composition of, 544
Bismuthyl, 220 corpuscles, S44
Bisulphate, quinine, bil detection of, in nrine, S77, 587
Bisalphide, carbon, 302 hydrocyan ic acid in the, 269
Bisulphite of lime, 280 plasmin, Geld
six itiin, 2a! root, 538
Ritartrate, potussium, 85 Blowpipe, analysis, 355, 356
Bitter almonds, oil of, 322, 435, 456, -fame, 136
4, ADT Blue cohosh, 507
water of, 268 coloring-matters, 553
696
Blue copperas, 152
flag, SOT
yum tree, 42
jinudigo, 553
litmus paper, 90
ointment, 210
Prussian, 165, 265, 269, 326, 554
stone, 200
Turnbull's, 164, 327, 554
vitriol, 152, 206
" Boiled oil, " 443
Boiling-point, definition of, 5
determination of, 505
Boiling-points of various substances,
St
Boldine, 467
Boldo oil, 467
Bonds, 375
Bondue seeds, 507
Bond uecelle Semina, 507
Bone-ash, 117, 315
-black, 207, 555
-earth, 117, 312
-oil, 511
Bones, composition of, 117, 312
Boneset, 507
Boracic acid, 318
Borate, glyceryl, 320
Inanganese, 140
Borates, 318
analytical reactions of, 320
Borax, 318
bead, 139
honey, 319
volumetric determination
17
Bordeaux turpentine, 415
Borie acid, 318 . ;
as an antiseptic, 319, 544
anhydride, 318
Borneene, 472
Borneo carmphor, 472
Borneo), 472
Boron, 315
chloride, 318
derivation of word,
fluoride, 318
Borots artrate, OD potassium, 319
Bos tuurus, 549
Bosw ellia, 479
Botany Bay kino,
of,
38
342
Boy le s law, 46
Brandy. , 422 22
Brass, ‘132 iv
Brassica: juncea, 427
; nigra, 427 4
Brazil powder, 412
wood, 452
INDEX,
Bread, 464
afrated, 485
alcohol in, 420
-making, 44
Breidiu, 478
| Brezilin, 552
Bricks, 338
Bright's disease, 576
Britannia metal, 186, 193, 222
| British gum, 492
Bromal, 453
alcoholates, 453
hydrate, 453
Bromate potassium, 81
Bromates, 257, 280
detection of, in bromides, 257
Bromic acid, 81, 280
Bromide, ammonium, 98, 256
antimony, 186
bismuth, 229
cadmium, 232
ethyl, 30s
ferrous, 155
hydrogen, 256
lithium, 104
phosphorus, 256, 313
potassium, 81, 257
volumetric determination
of, 626
silver, 237, 257
sodinm, 91, 257
starch, 268
sulphur, 287
vine, 134
Bromides, 255
analytical reactions of, 257
detection of bromates in, 257
quantitative analysis of, G60
separation of, from chlorides
and iodides, 261
Bromine, 255
analytical separation of, 258
chloride, 258
derivation of word, 38
its analogy to chlorine and jo-
dine, 264
solution of, 257
specific gravity, 264
test solution, 257
volumetric determination of
free, 770
water, 257
Bromoform, 400
Bromoformum, 400
Fromum, 255
Bronze, 193
aluminium, 14
leaf, 11M
| Bronsing-powder, 196
INDEX.
Broom-tops, 539
Brown coloring-matters, 555
hematite, 149
resin, 474
sugar, 48-4
Brucia, 525
Brucine, 525
distinction from morphine, 525
Brunswick green, 184
Bryoidin, 4738
Buchu, 467, 507
oil, 467
Buckthorn green, 554
-juice, 498
“ Bumping,’’ 267
Bunsen gas-burners, 29
Burdock, 507
Burgundy piten. 476
Burners,
Burnett’s cidlufecting fluid, 133
Burnt ochre, 552
sugar, 485, 555
umber, 555
Butane, 386
synthesis of, 3383
Butea frondosa, 342
Butter, 443, 545
of antimony, 187
of cacao, 142
of cocua, 442
of kokum, 443
of orris, 469
Butyl alcohol, 317, 424
chloral, 453
hydrate, 453
Butylene, 392
Butyrate, cupric, 348
ethyl, 405
Butyrates, 347
Butyric acid, 347, 453
aldehyde, 467
Butyrone, 464
Buxine, 529
Buzxus sempervirens, 529
By-products, 213
CABBAGE-ROBE petals, 552
Cacau-butter, 442
Cacody] oxide, 323
Cacodylate ferric 323
sodium, 323
Cacodylic acid, 323
Cadaverine, 511
Cade, oil, 478
Cadet’ 8 fuming liquid, 323
Cadinene, 415, 469
Cadmium, 232
analytical reactions of, 232
bromide, 2
697
Cadmium, chloride, 232
derivation of word, 38
hydroxide, 233
iodide, 232
oxide, 233
sulphide, 232, 233
Ceealpinia bonducella, 507
brasiliensis, 552
Ceesium, 682
Caffeina, 530
citrata, 531
effervescens, 531
Caffeine, 530
citrate, 531
physiological action of, 531
relation to the bromine, 531
synthetic, 539
Cajuputene, 467
Cajuput oil, 467
Cajuputol, 467
Cajug coal, 193
Calabar bean, 537
Calamina prxparata, 134
Calamine, 131
prepared, 134
Calamus draco, 4735
Calcareous precipitated sulphur, 286
Calcic sulphate, phosphate, etc., see
Calcium.
Calcit bromidum, 113
carbonas precipitatus, 114 .
chloridum, 113
hypophosphis, 118, 329
phosphas precipitatus, 117
sulphas exsiccatua, 112
Calcined magnesia, 126
Calcis, liquor, 114
syrupus, 114
Calcium, 112
acetate, 28]
analytical reactions of, 121
arsenate, 1&5
bicarbonate, 301
bisulphite, 2&9
bromide, 113
carbide, 122, 395
carbonate, 112, 115, 296 ~
precipitated, 114
chloride, 112
removal of iron from, 113
citrate, 308, 310
derivation of word, 38
flame, 122
fluoride, 112, 327
in bones, 118
gummate, 121
hydroxide, 114
hypochlorite, 121
hypophosphite, 118, 329
698
Calcium, in presence of barium, |
strontium, and magnesium,
detection of, 121
lactate, S31
lactophosphate, 331
malate, 332
meconate, 32
metagumimate, 494
oxalate, S03
oxide, 115
phosphate, 112, 117, 312
acid, S15
polysulphide, 286
quantitative determination of
4b
santonate, 504
silicate, 112, 337
strontium, and barium, separa-
tion from magnesinm, 128
sulphate, 112, 122, 200
in precipitated sulphur, 324
test solution, 128
sulphide, 120
sulphite, 289
tartrate, 305, 307
thiosulphate, 286
Cale-spar, 112
Caleuli, urinary, 572
examination of, 589
Calendula, 507
Calendulin, 507
Caliche, 271
Calomel, 215, 220, 255
test for corrosive sublimate in,
215
Calotropis, HOT
gigantea, HOT
procera, }0T
Caulwmba, 530
root, 530
Calz, 113
chlorinata, 119, 277
sulphurata, 120
Cambogia, 47)
Camphene, 415
Camphor Borneo, 472
cerate, 473
Dutch, 472
Formosa, 472
hydrous, 472
laurel, 472
liniment, 473°
monobramated, 472
oil, 472
spirit, 473
water, 472
Camphora, 472
morohromata,
(amphoric acul, 4
aa
i
aT
ir
‘
i
~_
i
INDEX.
Camphoronie acid, 473
Camphors, 472
Cam-wood, 552
Canada balsam, 415, 478
Canadian hemp, S07
moonseed, 530
turpentine, 415
Candle-flame, composition of, 28
Canelle cortex, WT
Cane-sigar, 482
Cannabene, 475
Cannabin, 474
Caunabinine, 475
Cannabia indica, 467, 474
oil of, 474
sativa, 475
Cantharidic acid, 473
Cantharidin, 473
Cuntharis, 473
Caoutchin, 471
| Caoutchouc, 471
Capacity, unit of, 18
Capillary, 505
Caprice acid, 455
Caproate, glyceryl, 442
Caproic acid, 442, 455
Caprylate, glyceryl, 442
Caprylic acid, 442, 455
Capsaicin, 531
| Capsicin, 477
hydrochloride, 531
sulphate, 531
| Capsicum, 477, 531
fruit, 477, 531
resin of, 475
oil, 443
Caramel, 485, 555
Caraway-oil, 467
Carats fine, 197
Carbamate, ammonium, 96
ethyl, 455
Carbamiec acid, 455
Carbamide, 455
Carbamines, 447
Curbazotic acid, 445, 452
Carbide, calcium, 121, 395
Carbinol, 418
methyl, 419
Carbinols, 417
Carbo animalia, 297
purificatus, 207
ligqui, 297
Carbohydrates, 450
Carbolates, 434
Carholic acid, 432
antidotes to, 434
Carbon, 36, 207
bisulphide, 302
INDEX.
Carbon, combustion of, 36
compounds, chemistry of, 368
derivation of word, 38
disulphide, 302
monosulphide, 302
monoxide, see Carbonic oxide.
nucleus, 377
oxychloride, 399
quantitative determination of,
in organic compounds, 670,
et seq.
silicide, 339
tetrachloride, 396
Carbonate, ammonium, 96
solution of, 97
barium, 110
bismuth, 230
calcium, 112, 114, 298, 300
ferrous, saccharated, 152
. hydrogen, 298
iron, 152
lithium, 103
Magnesium, 123, 124, 126, 301
potassium, 72
acid, 76
sodium, 86, 89
acid, 88
chemically pure, 614
manufacture of, 39
strontium, 112
zine, 131, 134
Carbonates, 207
analytical reactions of, 300
detection of, in presence of sul-
phites or thiosulphates, 300
gravimetric determination of,
665
volumetric determination of
alkaline, 618
Carbonet Disulphidum, 302
Carbonic acid, 77, 297, 455
gas, 36
anhydride, 36, 298
generation of, 76
solubility of, in water, 299
specific gravity of, 300
oxide, 36, 299, 304, 326
Carbonization, 107
Carbonyl, 417
chloride, 399
Carborundum, 339
Carboxyl group, 384, 417
Carburetted hydrogen, light, 385
heavy, 392
Cardamom-oil, 467
yzreater, 468
lesser, 467
Cardamomum, $67
Carica papaya, 531, 549
699
Carmine, 323
Carminic acid, 323
Carnauba wax, 426, 453
Carnallite, 71
Carnine, 511
Carolina yellow jasmine, 535
Caro's acid, 296
Carpaine, 531
Carragcen moss, 494
Carrotin, 552
Carthamin, 553
Carthamus tinctortous, 553
Carum, 467 ;
ajowan, 466
capticum, 470
Carvacrol, 471
Carvene, 467
Carvol, 467
Carvone, 467, 469
Caryophyllene, 415, 467
Cascara sagrada, 412
Cascarilla, 467
-oil, 467
Cascarillin, 507
Casein, 544
vegetable, 546
Caseinogen, 544
Cassava, bitter, 488
Cassia fistula, 484
-vil, 467
Cassius, purple of, 199
Cast-iron, 151
Castile soap, 441
Castilloa elastica, 471
Castor, 475
fiber, 475
oil, 444
Castorin, 475
Catechin, 342
Catechu, 342, 555
Catechuic acid, 342
Cathartie acid, 498
Cathartogenic acid, 498
Cathode, 68
Cauluphillum Thalictroides, 507
Caustic, 235
lime, 113
lunar, 235
potash, 72
soda, 86
Cayenne pepper, 53]
Cedra-oil, 466
© Celandine, 5
Celestine, TL
Cellulin, 495
Celluloid, 496
Cellulose, 495
of stareh, 489
Cements, 338
700
Centesimal composition, 60
Cenutiare, 41
Centigrade thermometer, 44
Centigramme, 41
Centimetre, 41
Cephaéline, 532, 534
Cephaélis ipecacuanha, 532, 544
Cera alba, 426
Hava, 426
Cerasin, 494
Cerate Goulard’s, 224
Cernates, 592
Ceralnm camphor, 473
cantharidis, 473
plumbi aubacetatia, 224
Ceresine, 426
Cerit oxralas, 172
Cerite, 171
Cerium, 171
derivation of word, 38
oxalate, 172
potassium sulphate, 172
Ceroleine, 426
Cerotie acid, 388, 453, 455
Cery! alcohol, 426
cerotate, 426
Cefaceum, 425
Cetine, 426
Crtraria islandica, 491
Cetraric acid, 823
Cetyl alcohol, 425
hydroxide, 425
palmitate, 426
Cevadilla, 540°
Cevadilline, 40
Cevadine, 546, 40
Ceylon “ moss,’ 494
Chalcedony, 337
Chalk, 112 , 455
F ‘rench, 555.
prepared, 117
stones, 50]
Chalybeate water, 149
Chamber c rystals, 291
process for sulphuric acid man-
. nfae ture, 201
Chameleon mine ral, 1 a0
Cc ‘hamomile > flowers, 466
all, 466 ©
C har, 107
eure Ase
€ "hs aras, 47! 75 Poa
“ Tharco are t 6, 2 oo7
esoloring power of, 298
om yarified, 27 ~
wood, 298
Charles's law, 46
Charta sinapia, 427
Chartreuse, 422
INDEX,
Chaulmoogra oil, 444
Chavicic acid, 538
Chavicol, 343
Chebulic myrobalans, 340
Cheese, 545
poison, 511, 571
| Chelerythrine, 538
| Chelidonium, 535
Chemical action, illustration of by
“tdepcatge 61, 72
affinity, 50
changes, 49
characteristics of, 49
disappearance of properties
during,
equations and diagrams
representing, 72
heat given out or absorbed
during, 50
take place between definite
quantities of substances,
51
combination laws of, 5!
by volume, laws of, 51
by weight, laws of, 51
erent from mechan
mixture, 37, 50
compound, 25, 49
definition of, 50
diagrams, 62, 73
equations, 61, 72
formule 59
notation, 58, ef seq.
philosophy, principles of, 49,
et sey,
reagents, xv,
symbols, 58
toxicology, 550
Chemicals, lists of, xvi.
Chemistry, art of, 18
definition of, 49
derivation of the wor, 18
object of, 17
of carbon componnds, 268
organic, 368
science of, 18
Chemists, pharmaceutical, 19
| Cherry-laurel water, 268, 487
sigar in, 482
-tree gum, 494
wild black, 498
| Chestnut-brown, 555
¢ ‘hian turpentine, 415
Chicory, 491
Chili saltpetre, 271
nitre, 271
—Chimaphila, 498
INDEX,
Chimaphila umbellata, 498
China clay, 338
Chinese green, 48
yellow, 551
Chinoidine, 522
Chinoline, 511
Chirata, 335
Chiratin, 335
Chirotogenin, 335
Chiretta, 335
Chiloral, 449
aleoholates, 450, 552
butyl, 453
croton, 453
hydrated, 450
_ determination of, 451
Chioralformamide, 452
Chloralformamidum, 452
Chloralose, 452
Chloralum hydratum, 450
Chlorate, calcium, 278
potassium, 277
preparation of
from, 20 —«yj.
sodium, 279
Chlorates, 277
analytical reactions of, 279
Chloraurate, sodium, 198
Chlorauric acid, 198
Chioretone, 424
Chlorie acid, 120, 277
Chloride, acctyl, 282
aluminium, 147
ammonium, 9
antimony, 186
arsenic, 179
auric, 198
barium, 109
boron 318
bromine, 258
calcium, 112
chromic, 166
chromy!], 169
cobalt, 142
detection of, in presence of bro-
mide or iodide, 262
ethyl, 398
ethylene, 392, 393
ferric, 155
ferrous, 154, 156
gold, 198, 570
iridium, 570
irom, 154, 156, of seq.
lead, 225
lime, 110
oxygen
| Chloride, magnesium, 123
mauganese, 165
mercuri-ammonium, 218
mercuric, 213
mercuroes-ammonium, 220
mercurous, 215, 219
methyl, 398
nickel, 143
nitrosyl, 274
palladium, 570
phosphorus, 283, 313
platinic, 200
platinum and am- |)
monium
and Jithium |
Seo
chloro-
and potassium | platinates
and sodium
potassium, 71
silicon, 339
silver, 234, 255
sodium, 86, 252
sulphur, 287
stannic, 194
stannous, 194
solution of, 194
zine, 133
Chlorides, 252
analytical reactions of, 255
detection of, in presence of
bromides and iodides, 262
determination of, 659
quantity present in urine, 580
separation of, from bromides
and iodides, 261
Chlorinated lime, 119, 278
volumetric determination
of, 636
potash, 377
soda, solution of, 91, 277
volumetric determination
of, (36
Chlorination, 395
| Chlorine, 33, 252, 254
acids, 280
as a disinfectant, 35
bleaching by, 35
collection of, 44
derivation of word, 38
hydrate, 254
its analogy to bromine and
iodine, 264
liquid, 254
peroxide, 279
preparation of, 34
properties of, 34
relative weight of, 36
solubility in water, 34
solution of, 254
specific gravity, 264
702
Chlorine, substitution, 395
the active agent in bleaching-
powder, 120
volumetric determination of,
Ls)
-witter, 254
Chlorochromic anhydride, 109, 263
Chloroform, Sv6, 390
water, 400
Chloroformum, 309
Chlorophyll, 299, 554, 592
Chloroplatinate, ammonium,102, 201
lithium, 104
potassium, 85, 201
sodium, 201
Chloroplatinic acid, 199
Chocolate, 442
Cholalie acid, 550
Cholesterin, 440, 591
Cholic acid, 550
Choline, 511, 550
Chondrin, 547
a rodendron tomentowwm, 520
Chondrua, 494
Christmas rose, 501
Chromate, barium, 110
conversion of a, into a chromic
salt, 107
lead, 167, 169, 226
mercurous, 221
potussinm, 167
silver, 238
strontium, 112
Chromates, 166
analytical reactions of, 168
C ‘hrome-alum, 147, 168
-ironstone, L66
Oran Ke a2
-red, 5
-V iow. 226,
t ‘hromes, 22
Chromic acid, 167, 168
anhydrine, 166, 168
hydroxide, 169
oxide, 166, 555
. hy drous, aod
‘salts, 166
_ analytical renctions of, 169
_ sulphate, 166, 168
¢ "hromit Trivridum 168°
Cc ‘hromite, , 166 ane
‘Chromium, 166—
S51
analytic al reactions | of, 169, 170 |
e hloride, 166 Z
de rivation of word, 38
oxides, 166 — 7
oxy ‘hydroxides S, 17 7
Se sparation of, from aluminium |
and iron, 17 0, 171
INDEX,
Chromium, sulphate, 166, 165
trioxide, 165
Chromogens in urine, 580
Chromous salts, 166
| Chromule, 554
| Chromy! chloride, 169
Chrysammic acid, 413
Chrysarobin, 412
Chrysarobinum, 413
Chrysatropic acid, 529
Chrysophan, 412
Chrysophanie acid, 412
Churning, 545
Churras, 475
Chymosin, 444
Cieuta virowa, 468
Cicutine, 533
Cider, 422
Cimifuga, 507
racemosa, HOT
| Cimicifugin, 507
| Ciuchamidine, 523
Cimchona, 518
alkaloids, 518
bark, 518
rubra, 518
Cinchonicine, 523
Ciuchoniding. sulphas, 522
-Cinchonidine, 521
hydriodide, 522
sulphate, 522
tartrate, 522
| Cinchoninse sulphas, S22
| Cinchonine, 522
hydriodide, 522
sulphate, S22
tartrate, 522
Cineol, 467, 468
Cinnabar, 200, 552
Cinnaldehydum, 467
Cinnamaldchyde, 460, 467
Cinnamein, 460
Cinnamene, 40 :
| Cinnamie acid, 323, 461
| aldehyde, 460, 467
series of acids, 460
| Cinnamel, 460
| (Cinmmomum camphora, 472
olirert, 470
Cinnamon-oil, 467
‘Cinnamy! aleohol, 460
cinnamiate, 460
¢ ‘iexampelos Pareira, 529
| Cissampeline, 529
Citral, 467
(Citrate, ammonium, 6
bismuth, 230
wnmonium, 160, 230
) caffeine, 531
INDEX,
Citrate, calcium, 309, 310
ferric, 161
ferrous, 161
irow, 161
and ammonium, 159, 411
and quinine, 159, 160, 519
lithium, 104
magnesium, 126
nicotine, ad
potassium, 77
volumetric determination
of, 619
silver, 310
amlio-ferrous, 161
strychnine, 524
Citrates, 308
unalytical reactions of, 310
Citrowes, 415
Citric acid, 308, 462
action of heat on, 309
volumetric determination
of, G23
measeige: neg he 308
Citromycea glaber, 300
Pfefferianus, 300
Citron-oil, 467
Cc itronella- oil, 468
Citronellal, 467, 471
Citrouellol, 469
Citrus, 466
avrantinm, 467
bergamia, 466
limetta 466
medica, 466
Classification, 108, 129, 242
Clausius'’s theory, 30
Claviceps purpurea, 475
Clay, 146, 337
China, 338
ironstone, 149
Cloves, oil of, 467
Club-moss, 444
Coal, authracite and other kinds,
193
~brasses, l 49
=+2as, 297, 435
for balloons, 29
products of, 45
-tar colors, 555
Cobalt. 141
analytical reactions of, 142
and sodjum nitrite, 85
arsenide, 141
blue, 553
derivation of word, 3s
«glance, 141
oxide, 141, 553
separation of, from nickel, 142
aulphate, 142
| Cobalt, sulphide, 142
Cobaltic ultramarine, 655
Cobulticyanide potassium, 142
Cobaltic nitrite potassium, 65, 142
Cocaine hydrochloridum, 532
Cocaine, 532
hydrochloride, 532
Cocaines, 532
Cocamine, 532
Coccerin, 329
Coceulus indicus, 502
Cocens, 325, 553
cacti, 323
ilicis, 180
Cochineal, 323, 452
Cocoa, 442, 540
nibs, 442
nut, 442
oil, 442
Cocos nucifera, 442
| Codamine, 517
Codeia, 516
Codeima, 516
Codeinw phosphas, 516
wu! phats, 516
Codeine, 516, 541
phosphate, 516
sul phate, 516
| Cod-liver, 443
| Coffee, 530
Cohosh, black, 507
blue, 507
| Coin, gold, 197
| Coinage, copper, 602
gold, Gt
silver, 224, 602
Coke, 36, 207
Colchiceine, 533
Colchict cormus, 633
armen, Ot3
Colchicina, 533
ae ‘alchicine, 533, M41
| Colchicum autumnale, 533
| Coleothar, 158
Collagen, 47
— hydrate of, 47
Collagens, 547
Collection of gases, 20, 21
Collidine, 512
| Collin, 681
Collodion, 495
cantharidal, 496
flexible, 496
Collodium, 495
cantharidum, 41h
704
Collodium, flexile, 496
Colloids, 543, G81
Colocynthis, 440
Colocyuthin, 499
Coluphene, 416
Colopholic acid, 474
Colophonie acid, 474
hydrate, 474
Colophonine, 474
Colophony, 415, 474
Coloring matters, 551
Colorless indigo, B53
Combination, chemical, by a
50, 51
by vol ume, 51
Combining capacity, 63
[a pages ol, 56, et seq.
Combustible,
Combustion, 28
analysis for carbon and hydro-
gen, 671, ef seq.
for nitrogen, 673, 674
relation of oxygen to, 24
spontaneous, 163
supporters of, 26
Commiphora myrrha, 479
Composition of atmosphere, 32
bismuth salts, 220
centesimal, G0
ealculation of empirical
formula from, 60
calculation of, from form-
ula, 61
of oils and fats, 439
organic compounds, 370
percent., 61
Compound ether, 401
Compounds, 50)
chemical, 37
definition of, 50
different from mechanical
mixtures, 37, 0)
of the elements, 70 /
Concentrated volatile oils, 465
Concentration, 251, 252
state of, 251
Conchinine, 521
Concrete oil of mangosteen, 443
Condensation, 130
Condenser, 130
Condensing-tub, 130
worto, 130
Confections, 484,
{ ‘onhydrine, 533
c On idk, ; kt
( ata! x bony
Coniine, 511, 533
salts of, bot
syothetic, 533
692
INDEX.
Conium, 533
—— macntatum, 533
Conqguinine, 521
Constant pro ee law of, 51
Constant wh
Constitution of alkaloids, 508
benzene series, 400
bleaching err 120
cinchons alkaloids, 523
morphine, 517
sae yee compounds, 374, 376,
et seq.
sults, 65, 251
uric acid, 346, 539
Constitutional formule, 375
Construction of formule, 59
Contact process for sulphuric acid
manufacture, 201
| Convolyalin, 501
Convolrulus scammonia, 505
Conylia, 533
Copaiba, 447
oil, 468
Copaivadl, 447
Copaivie acid, 447
Copal, 475
Copernicia ceriferd, 426, 453
205
acetylide, 395
ammoniun pepe peso =
analytical reacti
antidotes to, 208
arsenate, 184
arsenite, l=4, 208
black oxide, 206
blue, 553
carbonate, 554
coinage, 602
cuprons and cupric salts, 206
derivation of word, 38
detection of arsenic ju, 179
ferrocyanide, 208
flame, 208
hydride, 330
hydroxide, 207, 208
hydroxyearbonate, 205
in organic mixtures, detection
of, 561, 563
iodide, 206, 208, 261
melting-point of, 597
nitrate, 206
oxides, 206, 208
oxyacetate, 206
pyrites, 205
quantitative determination of,
haz
recovery of, from solutions, 207
sulphate, 206
INDEX. 405
Copper salphate, anhydrous, 205 Croten chloral, 453
sulphide, 206. 237 hydrate, 43
test for mercury compounds, oil, 444
2173
-ziue couple, 661
Copperas, blue, 132
Coriander-oil, 468
Coriandrol, 468
Cork, specific c gravity of, 604
-borers, 20
Cornutine, 476
Correction
of the volume of a gas
for pressure, 47, 604
for temperature. 4, 605
Corrosive sublimate, 214, 215
antidote to, 221
test for, in calomel, 215
Corundum, 146
Corydaline, 534
Corydalis cara, 534
Corypha cerifera, 426
Cocscsnium fenestratum, 530
Cotarnine, 499
Coto-bark, 499
false, 499
Cotoin, 499
Cotton-root bark, 507
-seed oil in olive oil, 435
cake, 511
-wool, 495
Couch-grass, 507
Coumarin. 460
Cowbane, 168
Cows’ milk, 545
“Cracking ’’ of hydrocarbons, 373
Cram p-back, 507
Cranesbill, 343
Cream, 545
of tartar, 71 84, 305
soluble, 319
Creatine, 510
Creatinine, 510
Cremnitz white, 555
Creosol, 4:33
Creosote, 433
Creonotum, 434
Cresol, 433, 43-4
Cresotic acid, 457
Cresylic acid, 133
Cyeta preparata, 117
Crinum astaticum, A
Crocetin, 551
Crocin, 551
Croceus (mineral), 153
of antimony, 1386
sativus, 551
45
Crotonic acid, 455
Crotoneleic acid, 444
Crotonylene, S4
Crown glass, S38
| Crucibles, 74, 335
Crade antimony, 186
potashes, 71
| Crum’s test for manganese, 141
, Crusocreatinine, 510
| Cryolite. 146, 360
, Cryptopine, 517
Crystal-glass, 3338
Crystallization, water of, 90
fractional, 2, KL
Crystalloids, 543
Cube sugar, 484
Cubeb camphor, 468
vil of, 468
oleoresin of, 477
pepper, 338
Cubebene, 468
Cubebin, 538
Cubic decimetre, 4l
nitre, 271
Cuca, see Coca.
Cucurbita maritima, 507
Pepo, 307
Cudbear, i344
Culvers root, 507
Cumin, 468
Cuminiec acid, 468
Cuminum cyminum, 468
Cummin, 468
Cupel, 659
Cupellation, determination of silver
by, 658
Cupre n hark, B23
Cupreine, 523
Cupri xulphas, DOE
Cupric acetate, 154
aceto-arsenite, 554
ammonium sulphate, 207
test solution, 1e4
arsenate, IS
arsenite, PS, 206
butyrate, $5
compotnds, 208
ferrocyanide, 208
hydroxide, 207, 208
nitrate, 206
oxide, 206, 208, 554
oxyucetate, 200
sulphate, 206
auhydrous, 206
sulphide, 206, 287
706
Cupric valerate, 348
uC Sd ete Si ae ee 144, 554
Cuprous hydride, 330
iodide, 206, 208, 261
oxide, 206, 482, 576
sulphide, 206
Cuprum, 33
Curacoa, 422
Curari, 525
Curarine, 525
Cucurma longa, 471, 551
Curcumin, 551
Curd soap, 441
Curds, 456, 544
and whey, 486, 544
Curine, 525
Currant, sugar in, 482
Curry powder, odor and flavor of,
471
Cusparidine, 534
Cusparine, 534
Cusso, 476
Cutch, 342
Cuttle-fish, 555
Cyanates, S24
Cyanic acid, j24
Cyanide, allyl, 427
inercuric, 266
nickel, 144
potassium, 266
nickel, 144
silver, 237, 268
Cyanides, 265
analytical reactions of metallic,
268
antidotes to, 270
double, 269
quantitative determination of,
626, 660
Cyanogen, 164, 265
chloride, 327
iodide, 259
Cyannrets, see Cyanides,
Cyder, see Cider.
Cymene, 406, 409, 466, 468, 472
Lé ‘ymol, 4166, 405
C 'ypripedin, 507
C 'ypripediun m, 507
- pubes ace m4, 8 507
i. systin, { 583 4
se “ale ula, | 501
Dane LA, Ms v1
Dalton’s. automatic theory,
Darmbose, ind
Danis le lion, 41
Daphne quidinm 476
laureola, 470
INDEX,
| Daphne mesereum, 476, 499
Daphuetin, 190
Daphnin, 499
Datura fastwosa, 535
Metel, 535
stramonium, 535
Daturine, 535
Dauglish’s bread, 455
Davy safety-lamp, 29
Deadly nightshade, 527
| Decane, 386
Decantation, 116
Decimal coinage, 42
Decoctions, 502
Decolorizing power of animal char-
coal, 205
Decomposition, ot)
double, 73
Decrepitation, 355
Decylene aleohol, 427
Deflagrating flux, 360
Deflagration, 50
Deliquescence, 91
Delphine, 534
Delphinine, 534
Delphinium staphysagria, 534
Del phineidine, 534
Densities, relative, 47
of gases, 45
of liquids and of solids, 47
Density, 47
vapor, 48, 605
Deodorizers, 35
Deodorizing liquid, 133
Deoxidation, 60
Deposits, urinary, 5&2
Derivation of names of elements,
ST, el
Desiccation, 640, 670
Desiccators, 640
Destructive distillation, 131, 281,
372
Detonation, 80
De Valangin's solution, 174
Dextrin, 492
Dextrorotation, O68
Dextrose, 452
Dextrotartaric acid, 306
Dhak tree, $42
Dhatura, 535
Dhiahetes mellitven, 580
Diabetic urine, 577
Diane etylmorphine, BG
Di-acid bases, 66
| Diamide, 4510
Diagrams, chemical, (2, 72, 32,
el weg.
| Dis yl disulphide, 427
| Dialysate,
G80
INDEX. 707
Dialysis, 339, 44, 680 | Dimercuri-ammonium iodide, 219
Diamines, 500 Dimethyl, 386
Diamond, 36, 205 benzene, 406
Diaphragms, 76 ethyl-carbinol, 425
Diastase, 449, 492 ketone, 464
action of, upon starch, 489, 492 vanthine, 530
Diatomic aleohols, 435 Dinitrocellulin, 495
Diazobenzene, 511 Dionin, 516
Dibasic acids, 66, 251, 461 Diosphenol, 467
Dibromethane, 304 Diospyros embryopteris, 343
Dichlorobenzene, 410 Dioxide, barium, 100
Dichloromethane, 396 chlorine, 279
Dichlorotoluene, 409 hydrogen, 109
Dichopais gutta, 471 iron, see Ferrie oxide,
Dichroism, 537 lead, see Lead peroxide
Dichromate, ammonium, 167 manganese, Los
potassium, 167 nitrogen, 271, 274, 275
standard solution of, 631 sodium, 23, ¥2
Didymium, 172 Dipentene, 415
Dietetics, 19 Dipterocarpus turbinatua, 477
Diethyl, 386 Disinfectant, chlorine as a, 35
Dicthylamine, 505 Disinfectants, 35
Diethy!-ammonia, 508 Disinfecting fluid, Burnett's, 155
ammonium iodide, 500 green, 139
-hydrazine, 510 purple, 139
-sparteine, 530 powder, 119
-sulphone-licthylmethane, 428 | solution, 120
-<limethylmethane, 428 Distillation, 129, 373
-methylethylmethane, 428 destructive, 131, 281, 372
Diethylene-diamine, 50) dry, 131, 372
Diffusate, 680 | fractional, 362, 373, 420
Diffusion of gases, 30 Distilled water, 131
relative rates of, 30 Disulphide, allyl propy!, 427
Digallic acid, 340 earbon, 302
Digitaligenin, 499 dially!, 427
Digitalin, 499 ~—Dita, 534
Digitaline erystatlisée, 500 Ditaine, 534
Digitalis, 400 Ditamine, 544
purpurea, 400 | Dithionic acid, 206
Digitalose, 49 Dobereiner’s lamp, 201
Digitogenin, 490 Dock, 412
Digitonin, 490 Dolomite, 123
Digitoxigenin, 500 Donovan's solution, 173
Digitoxin, 490 Derema ammoniacum, 470
Digitoxose, 500 Doremus Hreometer, 579
Dihydric alcohols, 417, 435 Double ehloride, aluminium and
Dihydroxyacetio acid, 455 sodium, 146
Dihydroxybenzenes, 455 cyanides, 260
Dihvydroxybutyrie acid, 455 decomposition, 73
Dihydroxyl derivatives of hydro- salts, f4, 146
carbons, 435 | Doundaké, 475
Dihydroxypropionic acid, 455 | Dover's powder, 534
Dihydroxyaueccinic acid, 462 Dracoalban, 475
Dihydroxytolucne, 437 Dracony!l, 400
Di-iodo-paraphenolaulphonie acid, | Dracoresen, 475
420 Dragon's bloml, 475
Di-iodo-salicylic acid, 458 Dried alum, 147
Di-ketone, 515 Dropped tin, 195
Dill-oil, 466 Dry distillation, 141, 372
708
Drying apparatus, 118
in vacuo, 118, 640
-oils, 443
precipitates, 118, (40
Dryobalanops aromalien, 472
Dryopteris filix-mas, 477
Duboimia myoporvides, 535
Duboisine, 535
Dulcamara, 535
Dulcamarin, 538
Dalein, 408
Duleite, 446
Dulong aud Petit’s law, 58
Dutch camphor, 472
Dyeing by mordants, 145
Dyer's saffron, 453
Dynamite, 438
EARTH, bone-, 117, 312
fuller’s 338
-nut oil, 444
vtech, 478
Earthenware, 338
Earths, alkaline, 129
Eau de Cologne, 466
de Javelle, 1
Ebonite, 471
Ebullition, 267
Ecboline, 475
Eegonine, 532
Echitamine, 534
Echitenine, 534
Echites scholaris, 534
Effervescing magnesium sulphate,
124
senedie r, compound, 306
soda-water, 209
sodium phosphate, 91
Efflorescence, 90
Egg, yolk of, 43
oll, 543
- white of, 543
Eleometer, 601
Elwoptens, 464
Elaidie acid, 456
Elastica, 471
E ‘late rin, 500
E laterinnm, 500
E Ide ‘T= lowe: “r oil, 470
E lecampane, 468 é'
E lec tric ‘amalgatn, | an
“— curre nt, produet tion of, 132
Electrodes, G7
E ‘lectrolysis, oR 67, 263, os
of pot: assim ace tate, ss
of sodium sulphate, 68
of sulphuric acid, 6
Electrolytes, 68
INDEX,
wt acs synthesis of, paraftins,
Element, definition of, 50
| Elements, 17, 15, 19, 37, 50, G2
and their compounds, 70
atomic weights, G&2
classification of, according to
analogy, 108
etymology of names of, 37, ef
seq.
metallic, 20
non-metallic, 20
of medical or pharmaceutical
interest, 19
of pharmaceutical interest, 14
symbols of, 59,
Elemi, 477
Elettaria repens, 467
Elutriation, 134
fractional, 362
Embelic acid, 324
| Emerald green, 554
Emery, 146
Emcetic cups, 156
tartar, 188
Emetine, 532, 534
nitrate, 534
Emodin, 412, 500
Empirical formula, 0, 608
deduction of, from com-
position percent., 60
Emplastrum hydrargyri, 210
plumhi, 225
Emulsin, 497
Emulsions, 480
Emulsum amygdala, 497
English red, 552
blue, 553
Enzymes, 421, 49
amylolytic, MD
pancreatic, 549
proteolytic, 549
steatolytic, 549
| Eosin, 411
Epsom salt, 123, 200
Equations, 61, 72
Equisetic acid, 300
| Equivalents, 62
Erbium, 682
Ergosterin, 475
Ergot, 475
Ergota, 475
Ergotin, 476
Ergotine, 475
Ergotinic acid, 476
Ergotinine, 475
Ericolin, 498
Erlangen blue, 554 | Ethyl, nitrite, 334, 401
Erucic acid, 444 enathylate, 405
Erythrite, 445, 462 | pelargonate, 406
Erythroretine, 412 sebacate, 405
Erythrose, 481 series of alcohols, 417
Erythrozylon coca, 532 sparteine, 539
Esculin, see seculin. suberate, 405
Eseramine, 537 -sulphuric acid, me Ethyl
Esere, 537 hydrogen sulphate.
Eseridine, 537 Ethylamine, 508
Eserine, 537 Ethylate, sodium, 423
Eseroline, 537 Ethylene, 389, 302
Essence of apple, 405 bromide, 393, 394
greengage, 405 chloride, 393
melon, 405 diamine, 509
mirbane, 407 | hydroxide, 417
mulberry, 405 iodide, 393
pineapple, 405 sulphate, 432
quince, 405 Ethylidene compounds, 455
Essences, 465 | lactic acid, 455
Essential oils, 464 | Ethylmorphine hydrochloride, 517
Esters, 401, 447 | Ethylsulphonic acid, 428
Etching, 328 Etymology of names of clements, 37
Ethal, 425 | Euealyptol, 467, 468
Ethane, 376, 382, 386 Eucalyptus oil, 468
constitution of, 382 Eucalyptus, 342
syuthesis of, 383 | amygdalina, 468
Ether, 429 cneortfolia, 468
acetic, 283, 403 dumosa, 468
aceto-acetic, 404 globulua, 408
compound apirit of, 442 maculata, 408
ethyl, 420 odorata, 468
hydrobromic, see Ethy! bromide. oleosa, 468
nitrous, 5, 401 rostrata, 468
ozonie, 577 | Euchlorine, 279
petroleum, 387 Eugenol, 467
Ethereal oil, 432 Euvodic aldehyde, 470
salts, 401, 447 Euonymin, 507
Ethers, 429, 447 | Kuonymusa, 507
mixed, 432 atropurpurens, OT
_ sulphur, 432 — Eupatorinm, AT
Ethiop's mineral, 219 perfoliatum, SA7
Ethyl, acetate, 233, 405 Euphorbium, 478
nceto-acetate, 404 Euphorbon, 479
alcohol, 419 Euxanthine, 551
ammonia, 508 Evaporation, 76, 107
amMinoninm iodide, 508 Everitt's salt, 267
bromide, Sos Eroqoninm perga, |
butyrate, 405 Explosion of gas, 27
carbamate, 455 Extract of malt, 493
chloride, 398 Goulard'’s, 224
ether, 420 Extracts, 592
-formic acid, 453 Extractum Helladonnx foliorum, 529
hydride, 386 cannabia Indiew, 475
hydrogen stilphate, 392, 420, ergole, A76
431 alyoyrrhyze, FOO
hydroxide, 417, 410 malli, 4
hydroxylamine, 500 physostiqnatia, B37
iodide, 398 Saturni, 223
710
FACE-ROUGE, 323
Fyeves, 572
Fahrenheit thermometer, 44
Pats and Oils, composition of, 439
Fats, vte,, anal ysis of, 681
solid, 442
Fatty acids, 440
matter in urine, 588
series, O74
substances, 374
Fel bovis, 549
purificatum, 549
Felspar, 337, 360
Fenchene, 415
Fennel-oil, 468
Fenugreek, 540
Fer réduit, 163
Fermentation, 420
acetic, 282, 421
alcoholic, 420, 421
smmoniacal, 421
butyric, 453
by soluble ferments, 420
citric, 300
lactic, 331, 421
mannitic, 421
nitric, 271
putrefactive, 421
viscous, 42]
Ferments, 421
amylolytic, 549
organized, 421
pancreatic, 549
proteolytic, 9
soluble, 421
steatolytic, 49
Ferratin, 549
Ferri carbonas, 153
saccharatus, 152
chlorici liquor, 156
elfras, 161 :
ef ammonti citraa, 159
quantitative determi-
nation of iron in, 650 |
sulphas, 147
— tartras, 161, 351
rid potasii tartras, 159, 161 308
quantitative determi-
nation of iron in, 650
ot quinine cifras, 161
solubilia, ‘ 160
et atrychnine c citras, 161
h eeraneee, 15 aT )
bh spepheayhts,:
lactas, O29
phoxphas solubilis, 161
pulvis, 163
pyrophosphas solubilis, 161, 336
% ~~
INDEX.
Ferri subcarbonas, 153
sulphas, 151
exrsiccatusa, 151
granulatus, 151
tersulphatis liquor, 157, 159
Ferric acetate, 158, 254, 333, 345
aceto-nitrates, 162
ammonium sulphate, 147
benzoate, 323
cacodylate, 323
chloride, 1 155, et seq.
anhydrous, 155
citrate, 161
ferrocyanide, 326
gallate, 344
hippurate, 325
hydroxide, 157, 165
hydroxycarbonate, 166
iodate, 280
meconate, 332, 344
nitrate, 162
oxide, 149, 155
separation from phosphates
and oxalates, 359
oxyacetate, 234
oxyhydroxide, 149, 157
oxyiodate, 2580
oxysulphate, 152
phosphate, 161, 316
soluble, 161
salts, 150, 145, et seq
analytical reactions of, 164,
165
volumetric determination
of, 637
succinate, 340
sulphate, 157
tannate, 165, 341
thiocyanate, 185, 269, 332, 344
valerate, 347
Ferricyanide, ferrous, 164, 327
potassium, 326
Ferricyanides, 326
Ferricvanogen, 164, 387
Ferrocyanide, cupric, 208, 426
ferric, 164, 326
ferrous, 164
potassium, 265, 326
ferrous, 267
zinc, 137
Ferrocyanides, 325
Ferrocyanogen, 164, 326
Ferrous ammoniom salphate, 152
arsenate, 158, 177A
bicarbonate, 149
bromide, 155
carbonate, 149, 152
saccharated, 152
chloride, 154
INDEX.
Ferrous chloride, anhydrous, 156
citrates, 161
ferricyanide, 165
ferrocyanide, 165
hydroxide, 165
iodide, 154
phosphate, 153
potassium ferrocyanide, 267
salts, 151, et seq.
analytical reactions of, 164
volumetric determination
of, 631, 632, 633, 634
sulphate, 151
sulphide, 37, 154, 164, 165
tartrate, 161
Ferrum, 39, 150
reductum, 163, 650
Ferula Futida, 479
Ferulaic acid, 479
Fibrin, 543
ferment, 544
insoluble, 544
vegetable, 546
Fibrinogen, 544
Ficus, 48:2
elastica, 471
Fig, 482
Filicie acid, 444
Filmarone, 444
Filter, to dry, 640
-paper, 115, 639
Filters, 115
ashless 639
Filtrate, 118
Fine gold. 198
Fire-clay, 214, 338
-damp, 385
Fir wool, 416
oil, 416
Fischer's salt, 85, 142
Fisetin, 551
Fish-poison, 511
Fixed oils, 443
and volatile oils, difference
between, 443
Flag, blue, 507
Flake manna, 445
white artists’, 555
toilet, 555
Flame, oxidizing, 136
reducing, 136
structure of, 28
Flare, 442
Flashing-point, 416
Flavaspidie acid, 444
Flax seed, 194
Fleitmanun’s test for arsenic, 181
Flexible collodion, 496
Flint, 337
711
Flint glass, 338
Flores zinct, 136
Flour, 488
Flowers of sulphur, 284
Fluidectractum belladons radicis, 529
Srangule, 498
glycyrrhize, 500
hemamelidis, 507
hydrastis, 530
tpecacuanhe, 535
“ Fluid magnesia,” 125
Fluorescein, 411
Fluoric acid, 328
Fluoride, boron, 318
calcium, 112, 327
in bones, 118
ethyl, 328
lithium, 104 +
silicon, 339
sodium aluminium, 146
Fluorides, 327
Fluorine, 323
derivation of word, 38
Fluor-spar, 112, 327
Fluosilicic acid, 328
Feeniculum, 468
Foenugreek, 540
Foil, tin, 193
Food, analysis of, 681
Formaldehyde, 200, 448
Formalin, 418
Formate, ammonium, 268
potassium, 401
Formates, 324
Formic acid, 324, 448, 455
Formica rufa, 324
Formosa camphor, 472
Formose, 448, 484
Formula weight, 59
Formuls, 59
calculation of composition per-
cent. from, 61
constitutional, 375
construction of, 59
empirical, 60, 608
deduction of, from com-
position percent., 60
graphic, 375
molecular, 60, 608
structural, 375
Formy] chloride, 396
Fousel-oil, see Fusel-oil.
Fowler's solution, 174
Foxglove, 499
Fractional crystallization, 82, 362
distillation, 362, 373, 419
elutriation, 134, 362
fusion, 362
lixiviation, 90, 362
698
Calcium, in presence of ‘barium,
strontium, and magnesium,
detection of, 121
lactate, SUL
lactophosphate, S31
malate, 32
meconate, 342
metaguminate, 494
oxalate, 303
oxide, 113
phosphate, 112, 117, 312
acid, 315
polysulphide, 286
quantitative determination of
6-46
santonate, 504
silicate, 112, 337
strontium, and barium, separa-
tion from magnesium, 128
sulphate, 112, 122, 200
in precipitated sulphur, 324
test solution, 128
sulphide, 120
sulphite, 289
tartrate, 305, 307
thiosulphate, 286
Cale-spar, 112
Culeuli, urinary, 572
examination of, 589
Calendula, SOT
(ulendolin, 507
Caliche, 271
Culomel, 215, 220, 255
test for corrosive sublimate in,
215
Calotropia, 507
gigantea, 507
procera, SOT
Calumba, 550
root, 5340
Calx, 113
chlorinata, 119, 277
sulphurata, 120
Camboygia, 479
(umphene, 415
Camphor Borneo, 472
cerate, 473
Dutch, 472
Formosa, 472
hydrous, 472
laurel, 472
liniment, 473
monobromated, 472
oll, 472
spirit, 473
water, 472
(a mpnho ra, 472
morobromata, 472
Camphoric acid, 473
INDEX.
Camphoronic acid, 473
Camphors, 472
(am-wood, 552
Canada balsam, 415, 478
Canadian hemp, 507
moonseed, 530
turpentine, 415
Candle-flame, composition of, 28
Canelle cortex, HT
Cane-sugar, 482
(annabene, 475
Cannabin, 474
Cannabinine, 475
Cannabis tndica, 467, 474
oil of, 474
sativa, 475
Cantharidie acid, 473
Cantharidin, 473
Cantharis, 473
Caoutchin, 471
Caoutchoue, 471
Capacity, unit of, 18
Capillary, 593
Caprice acid, 455
Caproate, glyceryl, 442
Caproic acid, 442, 455
Caprylate, glyceryl, 442
Caprylie acid, 442, 455
| Capsaicin, 531
Cupsicin, 477
Capsicine, 531
hydrochloride, 531
sulphate, 531
Capsicem, 477, 531
fruit, 477, 531
resin of, 475
oil, 443
Caramel, 485, 555
| Curaway-oil, 467
Carats fine, 197
Carbamate, ammonium, 96 ©
ethyl, 455
Carbamic acid, 455
Carbamide, 454
Curbamines, 447
Carhazotie acid, 435, 552
Carbide, calcium, 121, 396
Carbinol, 418
methyl, 419
| Carbinols, 417
(urhbo animalia, 297
purificatus, 207
liqni, 297
Curbohydrates, 480
Curbolates, (4
Carholic avid, 432
antidotes to, 434
Carbon, 34, 27
bisulphide, 302
INDEX.
Carbon, combustion of, 36
compounds, chemistry of, 368
derivation of word, 38
disulphide, 302
monosulphide, 302
monoxide, see Carbonic oxide,
nucleus, 377
oxychloride, 399
quantitative determination of,
in organic compounds, 670,
et seq.
silicide, 339
tetrachloride, 396
Carbonate, ammonium, 96
solution of, 97
barium, 110
bismuth, 230
calcium, 112, 114, 208, 300
ferrous, saccharated, 152
hydrogen, 208
iron, 152
lithium, 103
magnesium, 123, 124, 126, 301
potassium, 72
acid, 76
sodium, 86, 89
acid, 5S
chemically pure, 614
manufacture of, 8)
strontium, 112
zine, 131, 134
Carbonates, 217
analytical reactions of, 300
detection of, in presence of snl-
phites or thiosulphates, 500
gravimetric determination of,
volumetric determination of
alkaline, 618
Corbonet Disulphidum, S02
Carbonic acid, 77, 207, 455
gas, 1G
anhydride, 36, 298
generation of, 76
solubility of, in water, 260
specific gravity of, 300
oxide, 36, 200, S04, 326
Carbonization, 107
(urbonyl, 417
chloride, 390
Curborundum, 339
Carboxyl group, 384, 417
Carburetted hydrogen, light, 385
: heavy, 392
Cardamom-oil, 467
greater, 405
lesser, 467
Cardamomum, 407 |
Carica papaya, 531, 49
Carmine, 323
| Carminic acid, 323
| Carnauba wax, 426, 453
| Carnallite, 71
| Curnine, 511
Carolina yellow jasmine, 535
Caro’s acid, 206
| Carpaine, 531
| Carrageen moss, 4{4
Carrotin, 552
Carthamin, 553
Corthamus tinclortous, 553
Carum, 467
ajowan, 466
capticum, 470
Carvacrol, 471
Carvene, 467
Carvol, 467
Carvone, 467, 469
Caryophylene, 415, 467
Cascara sagrada, 412
Casearilla, 407
-oi], 467
Cascarillin, 507
| Casein, 544
vegetable, 546
Caseinogen, 544
(Cassava, bitter, 488
| Caawia fistula, 484
-oll, 407
Cassius, purple of, 199
Cast-iron, 151
Custile soup, 441
Castilloa elustica, 471
Castor, 475
jiber, ATD
oil, 444
Castorin, 475
Catechin, 342
Catechu, 342, 555
| Catechuic acid, 342
Cathartic acid, 498
Cathartogenic acid, 408
Cathade, 68
Caulophillum Thalictroides, S07
(Cnustic, 235
lime, 115
lunar, 235
potash, 72
sodu, at
Cayoune pepper, 531
Cedra-oil, 466
Colandine, 538
('olestine, LI1
'Cellolin, 495
Celluloid, 406
(ellulose, 495
of starch, 480
Cements, 435
700
Centesimal composition, 60
Ceutiare, 41
Centigrade thermometer, 44
Centigramme, 41
Centimetre, 41
Cephaeline, 532, 534
Cephaélia ipecacuanha, 532, 534
Cera alba, 426
flava, 426
Cerasin, 494
Cerate Gonlard's, 224
Cerates, 592
(vrafum camphorw, 473
cantheridis, 473
plumbi subacetatia, 224
Ceresine, 426
Certi oxralas, 172
Cerite, 171
Cerium, 171
derivation of word, 38
oxalate, 172
potassium sulphate, 172
Ceroleine, 426
Cerotic acid, 388, 453, 455
Ceryl aleohol, 426
cerotate, 426
(Crtacenm, 425
Cetine, 426
Cetraria islandica, 491
Cetraric acid, 323
Cetyl aleohol, 425
hydroxide, 425
palmitate, 426
Cevadilla, 540
Cevadilline, 40
Cevadine, 536, 540
Ceylon * “moss,” 44
c ‘haleedony, 337
Chalk, 112, Aad
French, 555
prepared, 117
«Stones, 591
Chalybeate water, 149
Chamber crystals, 291
process: for sulphuric acid man-
. ofacture, 291
Chameleon mineral, 130
Cc ‘hamomile flowers, 468
: oil, 466
© ‘har, LOT
Cc ‘ha aris, 475 5 4
4 Tharcoal, 36, 297
“anim al, , 207
dee oloring power of, oR
purified, | 207
wood, 298 r
Chi srles “a's la aw, 46
/ ‘harta winapia, 4? 7
Chartreuse, 422
INDEX.
Chaulmoogra oil, 444
Chanlmugra, 444
Chavica officinarum, 538
Chavicic acid, 538
Chuvicol, 343
Chebulie myrobalans, 340
Cheese, 545
poison, 511, 571
ge aa 538
Chelidonium, 538
Chemical action, illustration of by
symbols, G1, 72
uflinity, 50
changes, 49
characteristies of, 49
disappearance of properties
during, 49
equations and diagrams
representing, 72
heat given out or absorbed
during, 50
take place between definite
quantities of substances,
5]
combination laws of, 5)
by volume, laws of, 51
by weight, laws of, 51
different from mechanical
mixture, 87, 50
compound, 25, 49
definition of, 50
diagrams, 2, 73
equations, 61, 72
formule 59
notation, 58, ef seq
philosophy, wwitchiles of, 49,
et wey,
reagents, xv,
symbols, 58
toxicology, 559
Chemicals, lists of, xvi.
Chemistry, art of, 18
definition of, 49
derivation of the word, 18
object of, 17
of carbon compounds, 368
organic, 368
science of, 18
Chemists, pharmaceutical, 19
Cherry-lanurel water, 268, 487
sugar in, 482
-tree gum, 494
wild black, 498
Chestnut-brown, 555
~Chian turpentine, 415
Chicory, 491
Chili saltpetre, 271
nitre, 271
| Chimaphila, 498
INDEX.
Chimaphila umbellata, 498
China clay, 338
Chinese green, 548
moss, 494
red, 552
wax, 426
white, 555
yellow, 551
Chinoidine, 522
Chinoline, 511
Chirata, 335
Chiratin, 335
Chirotogenin, 335
Chiretta, 335
Chloral, 449
alcoholates, 450, 552
butyl, 453
croton, 453
hydrated, 450
determination of, 451
Chloralformamide, 452
Chloralformamidum, 452
Chloralose, 452
Chloralum hydratum, 450
Chlorate, calcium, 278
potassium, 277
preparation
from, 20
sodium, 279
Chlorates, 277
analytical reactions of, 279
Chloraurate, sodium, 198
Chlorauric acid, 198
Chloretone, 424
Chloric acid, 120, 277
Chloride, acety], 282
aluminium, 147
ammonium, 93
antimony, 186
arsenic, 179
auric, 198
barium, 109
boron 318
bromine, 258
calcium, 112
chromic, 166
chromy]l, 169
cobalt, 142
detection of, in presence of bro-
mide or iodide, 262
ethyl, 398
ethylene, 392, 393
ferric, 155
ferrous, 154, 156
gold, 198, 570
iridium, 570
iron, 154, 156, e¢ seq.
lead, 225
lime, 119
of oxygen
701
Chloride, magnesium, 123
manganese, 138
mercuri-ammonium, 218
mercuric, 213
mercuros-ammonium, 220
mercurous, 215, 219
methyl, 398
nickel, 143
nitrosyl, 273
palladium, 570
phosphorus, 283, 313
platinic, 200
platinum and am- }
monium See
and lithium chloro-
and potassium | platinates
and sodium
potassium, 71
silicon, 339
silver, 234, 255
sodium, 86, 252
sulphur, 287
stannic, 194
stannous, 194
solution of, 194
zine, 133
Chlorides, 252
analytical reactions of, 255
detection of, in presence of
bromides and iodides, 262
determination of, 659
quantity present in urine, 580
separation of, from bromides
and iodides, 261
Chlorinated lime, 119, 278
volumetric determination
of, 636
potash, 377
soda, solution of, 91, 277
volumetric determination
of, 636
Chlorination, 395
Chlorine, 33, 252, 254
acids, 280
as a disinfectant, 35
bleaching by, 35
collection of, 34
derivation of word, 38
hydrate, 254
its analogy to bromine and
iodine, 264
liquid, 254
peroxide, 279
preparation of, 34
properties of, 34
relative weight of, 36
solubility in water, 34
solution of, 254
specific gravity, 264
702
Chlorine, substitution, 395
the active agent in bleaching-
powder, 120
volumetric determination of,
tick
-water, 254
Chlorochromic anhydride, 169, 263
Chloreform, S06, 399
water, 400
Chloroformum, 399
Chlorophyll, 209, 554, 592
Chloroplatinate, ammonium, 102, 201
lithium, 104
potassium, 83, 201
sodium, 201
Chloroplatinic acid, 199
Chocolate, 442 —
Cholalic acid, 550
Cholesterin, 440, 591
Cholie acid, 550
Choline, 511, 550
Chondrin, 547
Chondrodendron tomentosum, 520
Chondrus, 494
Christmas rose, 501
Chromate, barium, 110
conversion of a, into » chromic
salt, 167
lead, 167, 169, 226
mercurous, 221
potassium, 167
silver, 235
strontium, 112
Chromates, 166
: analytical reactions of, 168
Chrome-alum, 147, 168
-lronstone, 166.
“orange, 296
-red, 552
-yellow, 226, 551
( ‘hromes, 2236
Chromic ‘acid, 167, 168
anhydrine, 166, 168
hydroxide, 169
oxide, 166, 555
hy drous, {
salts, , 166 ’
¥! analy tical reactions of, 169
sulphate, 166, 168
f Chromit Trio: cidum, 168
( Chromite, 166
Chromium, 166
analy tie al re reactions of, 1469, 170
a chloride, 166. gg
de iv ation of Ww ord, 38
oxides, 166, -s
oxyhydroxides, 170 .
se paration. of, from aluminium
and iron, 170, 171
64
INDEX,
Chromium, sulphute, 166, 168
trioxide, 1tis
Chromogens in urine, 580
Chromous salis, 166
Chromule, 554
Chromyl chloride, 169°
~6Chrysammic acid, 413
Chrysarobin, 412
Chrysarobinum, 413
Chrysatropic acid, 529
Chrysophan, 412
Chrysophanic acid, 412
Churning, 545
Churras, 475
Chymosin, 544
|—~«Cieuta virosa, 468
Cieutine, 533
| Cider, 422
| Cimifuga, 507
racemosa, DOT
Cimicifugin, 507
Cinchamidine, 523
Cinchona, 515
alkaloids, 518
bark, 518
rubra, 518
Cinchonicine, 523
Cinchonidine, sulphas, 522
| Cinchonidine, 521
| hydriodide, 522
sulphate, 522
tartrate, 522
| Cinchonine sulphas, 522
Cinchonine, 522
hydriodide, 522
sulphate, 622
tartrate, 522
Cineol, 407, 468
Cinnabar, 200, 552
Cinnaldehydum, 407
| Cinnamaldehyde, 460, 467
Cinnamein, 460
Cinnamene, 460 ‘
Cinvamic acid, 323, 461
aldehyde, 460, 467
series of acids, 460
Cinnamol, 460
Cinnamomnm camphora, 472
oliveri, 470
| Cinnamon-oil, 467
Cinnamy!] alcohol, 460
| ¢innamate, 460
Cissampelos Pareira, 529
Cissampeline, 520
Citral, 467
| Citrate, ammonium, 98
bismuth, 230
ammonium, 160, 230
caffeine, 531
INDEX,
Citrate, calcium, 309, 310 Cobalt, sulphide, 142
ferric, 161 Cobaltic ultramarine, 554
ferrous, 161 Cobalticyanide potassium, 142
iron, 161 Cobaltie nitrite potassium, 85, 142
and ammonium, 159, +11 sodium, 85
and quinine, 159, 160, 519 | Coca leaves, 532
lithium, 104 Cocaidine, 532
magnesium, 126 Cocaina, 532
nicotine, 536 Cocaine: hydrochloridum, 532
potassium, 77 Cocaine, 532
volumetric determination | hydrochloride, 532
of, 619 Cocaines, 532
silver, 310 Cocamine, 532
sodio-ferrons, 161 Coccerin, 329
strychnine, 524 — Coceulus indious, 502
Citrabes, 305 Cocens, 323, 553
analytical reactions of, 310 cacti, 323
Citrenes, 415 wicia, 189
Citric acid, 308, 462 Cochineal, 323, 552
action of heat on, 400
volumetric determination
of, 623
fermentation, 309
Citromyces glaber, 309
Pfefferianus, 309
(itron-oil, 467
Citronella-oil, 468 Codeina, 516
Citronellal, 467, 471 Codeing phosphas, 516
Citrouellol, 469 sulphas, 516
Citrus, 466 Codeine, 516, 541
avrantinm, 467 phosphate, 516
bergamia, 466 sulphate, 516
limetta 466 | Cod-liver, 443
medica, 466 Coffee, 530
Classification, 108, 129, 242 Cohosh, black, 507
Clwosius’s theory, 30 blue, 507
Claviceps purpurea, 475 Coin, gold, 197
Clay, 146, 337 Coinage, copper, G02
China, 338 gold, 602
ironstone, 149 silver, 234, G02
Cloves, oil of, 467 Coke, 36, 207
(Club-moss, 444 Colchiceine, 533
wal, muthracite and other kinds, | Colchici cormus, 533
—«198 semen, O45
-brasses, 149 ' Colehicina, 553
-gas, 297, 392, 435 Colchicine, 533, 541
for balloons, 29 Colchicum anfumnale, 533
products of, 435, 555 Coleothar, 155
-tar colors, 554 Collagen, 547
Cobalt. 14) hydrate of, 547
analytical reactions of, 142 Collagens, 547
and sodium nitrite, 85 Collection of gases, 20, 21
arsenide, 141 Collidine, 512
blue, 553 Collin, 681
derivation of word, 34 Collodion, 495 —
-clanee, 141 cantharidal, 494
oxide, 141, 553 flexible, 496
separation of, from nickel, 142 | Collodium, 405
sulphate, 142 cantharidum, 496
704
Collodinm, Nexile, 496
Colloids, 43, 641
Colocynthis, 499
Coloeyuthin, 490
Coluphene, 416
Colopholic acid, 474
Colophonic acid, 474
hydrate, 474
Colophonine, 474
Colophony, 415, 474
Coloring matters, 551
Colorless indigo, 553
Combination, chemical, by weight,
50, 51
by volume, 51
Combining capacity, 63
proportions, 51, 56, et seq.
Combustible, 28
Combustion, 28
analysis for carbon and hydro-
gen, G71, et seq.
for nitrogen, 673, 674
relation of oxygen to, 24
spontaneous, 163
supporters of, 28
Commiphora myrrha, 479
Composition of atmosphere, 32
bismuth salts, 229
centesimal, 60
calenlation of empirical
formula from, 60
calculation of, from form-
ula, 61
of oils and fats, 439
organic compounds, 370
percent., 61
Compound ether, 401
Compounds, 50)
chemical, 37
definition of, 50
different from mechanical
mixtures, 37, 50
of the elements, 70
Concentrated volatile oils, 465
Concentration, 251, 252
state of, 251
Conchinine, 521
Concrete oil of mangosteen, 443
Condensation, 130
Condenser, 130
Condensing-tub, 130
worm, 130
Confec ti ons, 454, 592
Cobia, O34
Conicine, 533
Coniine, 51 e 533
salts of, 533
synthetic, 533
INDEX,
Contiwm, 533
macuiatum, 533
Conquinine, 521
Constant proportions, law of, 51
Constant white, 555
Constitution of alkaloids, 50s
benzene series, 400
bleaching powder, 120
cinchona alkaloids, 523
morphine, 517
organic compounds, 374, 376,
et seq.
salts, 65, 251
uric acid, 346, 539
Constitutional formalg, 375
Construction of formule, 59
Contact process for sulphuric acid
manufacture, 291
| Convolvulin, 501
Conrolrulus scammonia, 505
Conylia, 533
| Copaiba, 447
oil, 468
Copaivaol, 447
Copaivie acid, 447
Copal, 475
Copernicia cerifera, 426, 453
Copper, 205
acetate, 1S4
acetylide, 395
ammonium sulphate, 207
analytical reactions of, 207
antidotes to, 208
arsenate, 184
arsenite, 154, 208
black oxide, 206
blue, 553
carbonate, 554
coinage, 602
cuprous and cupric salts, 206
derivation of word, 38
detection of arsenic ijn, 179
ferrocyanide, 208
flame, 208
hydride, 330
hydroxide, 207, 208
hydroxycarbonate, 205
in organic mixtures, detection
of, 561, 563
iodide, 206, 208, 261
melting-point of, 597
nitrate, 206
oxides, 206, 208
oxyacetate, 206
pyrites, 205
quantitative determination of,
Ghz
recovery of, from solutions, 207
sulphate, 206
INDEX. 705
Copper sulphate, anhydrous, 206 Croton chloral, 453
sulphide, 206, 287 hydrate, 453
test fur mercury compounds, oil, 444
217 Crotonic acid, 455
-zinc couple, 661
Copperas, blue, 152
green, 152
Coptis-root, 530
Coptis Teeta, 530
Coriander-oil, 468
Coriandrol, 468
Cork, specific gravity of, 604
-borers, 20
Cornutine, 476
Correction of the volume of a gas
for pressure, 47, 604
for temperature. 47, 605
Corrosive sublimate, 214, 215
antidote to, 221
test for, in calomel, 215
Corundum, 146
Corydaline, 534
Corydalis cava, 534
Corypha cerifera, 426
Coscintum fenestratum, 530
Cotarnine, 499
Coto-bark, 499
false, 499
Cotoin, 499
Cotton-root bark, 507
-seed oil in olive oil, 435
cake, 511
-wool, 495
Couch-grass, 507
Coumarin. 460
Cowbane, 468
Cows’ milk, 545
“Cracking’’ of hydrocarbons, 373
Cram p-back, 507
Cranesbill, 343
Cream, 545
of tartar, 71 84, 305
soluble, 319
Creatine, 510
Creatinine, 510
Cremnitz white, 555
Creosol, 433
Creosote, 433
Creosotum, 434
Cresol, 433, 434
Cresotic acid, 457
Cresylic acid, 453
Creta prwparata, 117
Crinum astaticum, 505
Croeetin, 5501
Crocin, 551
Croccus (mineral), 158
of antimony, 186
sativus, 551
49
Crotoneleic acid, 444
Crotonylene, 394
Crown glass, 338
Crucibles, 74, 338
Crude antimony, 186
potashes, 71
Crum’s test for manganese, 141
Crusocreatinine, 510
Cryolite, 146, 360
Cryptopine, 517
Crystal-glass, 338
Crystallization, water of, 90
fractional, 82, 362
Crystalloids, 543
Cube sugar, 484
Cubeb camphor, 468
oil of, 468
oleoresin of, 477
pepper, 338
Cubeba, 538
Cubebene, 468
Cubebin, 538
Cubic decimetre, 41
nitre, 271
Cuca, see Coca.
Cucurbita maritima, 507
Pepo, 07
Cudbear, 554
Culvers root, 507
Cumin, 468
Cuminic acid, 468
Cuminum cyminum, 468
Cummin, 468
pel, 659
Cupellation, determination of silver
by,
Cuprea bark, 523
Cupreine, 523
Cupri sulphas, 206
Cupric acetate, 184
acetu-arsenite, 554
ammonium sulphate, 207
test solution, 184
arsenate, 184
arsenite, 184, 208
butyrate, 348
compounds, 208
ferrocyanide, 208
hydroxide, 207, 208
nitrate, 206
oxide, 206, 208, 554
oxyacctate, 206
sulphate, 206
anhydrous, 206
sulphide, 206, 287
706
Cupric valerate, 348
Cupro-ursenical pigments, 184, 554
Cuprous hydride, 330
iodide, Mi, 208, 261
oxide, 206, 482, S76
sulphide, 206
Cuprum, 38
Curacoa, 422
Curari, 525
Curarine, 525
Cucurma longa, 471, 551
Curcumin, 551
Curd soap, 441
Curds, 486, 544
and whey, 486, 544
Curine, 525
Currant, sugar in, 482
Curry powder, odor and flavor of,
471
Cusparidine, 534
Cusparine, 534
Cusso, ATG
Cutch, 342
Cuttle-fish,
(Cyanates, 5 4
Cyanic acid, $24
Cyanide, allyl, 427
mercuric, 266
nickel, 144
potassium, 266
nickel, 144
silver, 237, 268
Cyanides, 265
anilytical reactions of metallic,
antidotes to, 270
double, 260
quantitative determination of,
G26, GOO
Cyanogen, |64, 265
chloride, 327
iodide, 250
Cyanurets, see Cyanides,
Cyder, see Cider,
Cymene, 406, 400, 466,
Cymol, 466, 468
Cypr ‘ipedin, 507
¢ ypripedinm, 5 WT
— prben ace ns hs 507
C ystin, | 5a 3
ae e ale ‘ulus, 5f 01
Cc 'ytisine, ' 7%)
505
468, 472
DAMLIA, 4 .. ,
‘Dalton's 5 automatic theory, 52
Darnbose, 484
Dandelion, Tt)
Daphne quidinn ATG
laureola, 47 i
INDEX,
Daphne mezereum, 476, 499
Daphuetin, 499
Daphoin, 499
Datura fastuoaa, 535
Metel, 535
stramonimm, 535
Daturine, 535
Dauglish’s bread, 455
Davy safety-lamp, 24
Deadly nightshade, 527
Decane, 356
Decantation, 116
Decimal coinage, 42
Decoctions, 52
Decolorizing power of animal char-
econ), 298
Decomposition, 50
double, 73
Deerepitation, 355
Decylene alcohol, 427
Deflagrating flux, 500
Deflagration, 80
Deliquescence, 91
Delphine, 534
Delphinine, 534
Delphinium staphysagria
Delphinoidine, 534
Densities, relative, 47
of 45
of liquids and of solids, 47
Density, 47
vapor, 45, 605
Deodorizers, 35
Deodorizing liquid, 133
, 54
Deoxidation, st)
Deposits, urinary, 582
Dexireres of names of clemonts,
a7, ef seq,
Dasication 640, 670
Desiccators, 40
Destructive distillation, 131, 281,
oT2
Detonation, 80
De Valangin's solution, 174
Dextrin, 492
Dextrorotation, 306
Dextrose, 452 :
Dextrotartaric acid, 306
Dhak tree, 342
Dhatura, 535
| Piabetes mellitus, 650
Diabetic urine, 577
Diacety morphine, 516
Di-acid bases, 66
| Diamide, 510
| Diagrams, chemical, (2, 72, Se
et sey,
Dially! disulphide, 427
Dialysate, (is)
INDEX. 707
Dialysis, 339, 544, 680 Dimercuri-ammonium iodide, 21)
Diamines, 500 Dimethyl, 386
Diamond, 36, 298 benzene, 406
Diaphragms, 76 ethyl-carbinol, 425
Diastase, 449, 492 ketone, 464
action of, upon starch, 489, 4f2 xanthine, 539
Diatomie alcohols, 435 Dinitrocellulin, 495
Diazobenzene, 511 Dioniu, 516
Dibasic acids, 66, 251, 461 Diosphenol, 467
Dibromethane, 304 Diospyros embryopleris, 343
Dichlorobenzene, 410 Dioxide, barium, 109
Dichloromethane, 496 chlorine, 279
Dichlorotoluene, 400 hydrogen, 100
Dichopois gutta, 471 iron, se¢ Ferric oxide,
Dichroism, 537 lead, see Lead peroxide
Dichromate, ammonium, 167 Dhangunese, 135
potassium, 167 nitrogen, 271, 274, 275
standard solution of, 631 sodium, 23, U2
Didymium, 172 Dipentene, 415
Dietetics, 19 Dipterocarpus turbinatus, 477
Diethyl, 386 Disinfectant, chlorine as a, 35
Diethylamine, 508 Disinfectants, 5
Diethyl-ammonia, 508 Disinfecting fluid, Burnett's, 133
ammonium iodide, 500 green, 139
-hydrazine, 510 purple, 139
-sparteine, 539 powder, 119
-sulphone-diethylmethane, 428 | solution, 120
+limethyl methane, 428 Distillation, 129, 373
-methylethylmethane, 428 destructive, 141, 281, S72
Diethylene-diamine, 509 dry, 131, 372
Ditfusate, 680 fractional, 362, 373, 420
Diffusion of gases, 30 Distilled water, 131
relative rates of, 30 Disnlphide, ally) propyl, 427
Digallic acid, 340 carbon, 302
Digitaligenin, 499 : diallyl, 427
Digitalin, 499 | Dita, 54
Digitaline erystallisée, 500 | Ditaine, 534
Digitalis, 499 Ditamine, 534
purpurea, 409 Dithionie acid, 296
Digitalose, 499 Dobereiner's lamp, 201
Digitogenin, 499 Dock, 412
Digitonin, 499 Dolomite, 123
Digitoxigenin, 500 Donovan's solution, 173
Digitoxin, 490 Dorema ammontiacum, 470
Digitoxose, 500) Doremus Greameter, 479
Dihydric aleohols, 417, 435 Double chloride, aluminium and
Dihydroxyacetic acid, 455 sodium, 146
Dihydroxybenzenea, 455 eyanides, 2)
Diliwdroxybutyrie acid, 455 decomposition, 73
Dihydroxy! derivatives of hydro- salts, (4, 146
carbons, 435 Doundaké, 475
Dihydroxypropionie acid, 455 Dover's powder, 534
Dihydroxysuceinic acid, 462 Dracoalban, 475
Dihydroxytoluene, 437 Lrracony!l, 40)
Di-iodo-paraphenolsulphonie acid, | Dracoresen, 475
420 Dragon's blood, 475
Di-iodo-salicylic acid, 458 Dried alum, 147
Di-ketone, 518 Dropped tha, 10%
Dill-oll, 466 Dry distillation, 131, 372
708
Drying apparatus, 118
in vacno, L1H, 640
-ils, 443
precipitates, 118, 640
Dryobalanops aromatica, 472
Dryopteris filiz-mas, 477
Duboisia myoporoides, 535
Duboisine, 535
Dulcamara, 538
Dulcamarin, 538
Dulein, 408
Dulcite, 446
Dulong aud Petit's law, 58
Dutch camphor, 472
Dycing by mordants, 148
Dyer's saffron, 553
Dynamite, 438
EARTH, bone-, 117, 312
fuller’s 338
-nut oil, 444
pitch, 4758
Earthenware, 338
Earths, alkaline, 129
Eau de Cologne, 466
de Javelle, 91
Ebonite, 471
Ebullition, 267
Ecboline, 475
Eegonine, 532
Echitamine, 534
Echitenine, 534
Echites scholaria, 534
Effervescing magnesium sulphate,
124
powder, compound, 306
soda-water, 200
sodium phosphate, 91
Efflorescence, 90
Egg, yolk of, 543
oil, 543
white of, 543
Eleometer, GOL
Elaeoptens, 464 —
Elaidic acid, 456
Elastica, 471
E laterin, 500
Elaterin “in, 500
Elde r-flowe r oil, 47 70
E lecampane, 45
E lee tric a i wmalgam, | on
_ curre nt, production of,
Etectrodes, @7 '
. 28, 67, 368, Ba
of potassium acetate, 334
of sodium sulphate, 68
. of st} phuric me id, 68
Electroly tes, 68
122
| Elemi, 477
| Elettaria
| Elutriation, 134
INDEX,
na gh da synthesis of, paraffins,
Element, definition of, 50
Elements, 17, 18, 19, 37, 50, 682
and their compounds, 70
atomic weights, 682
classification of, according to
analogy, 108
etymology of names of, 37, ef
seq.
metallic, 20
non-metallic, 2)
of medical or pharmaceutical
interest, 19
of pharmaceutical interest, 10
bols of, 50, 682
repens, 467
fractional, 362
Embelia ribes, 324
robusta, 324
Embelic acid, 324
Emerald green, 554
Ewery, 146
Emetic cups, 186
turtar, 188
Emetine, 532, 534
nitrate, 534
Emodin, 412, 500
Empirical formula, 60, 606
deduction’ of, from com-
position percent, 60
Emplastrum hydrergyri, 210
plumbi, 225
Emulsin, 497
Emulsions, 480
Emulsum amygdalx, 497
English red, 552
blue, 553
Enzymes, 421, 49
amylolytic, 549
pancreatic, 49
protolytic, 549
steatolytic, 549
Eosin, 411
Epsom salt, 123, 290
Equations, 61, 72
Equisctic acid, 309
Equivalents, 62
Erbium, 682
Ergosterin, 475
Ergot, 475
Ergota, 475
Ergotin, 476
Ergotine, 475
Ervotinic acid, 476
Ergotinine, 475
Ericolin, 498
INDEX.
Erlangen blue, 554
Erucic acid, 444
Erythrite, 445, 462
Erythroretine, 412
Erythrose, 481
Erythrozylon coca, 532
Esculin, see Esculin.
Eseramine, 537
Esere, 537
Eseridine, 537
Eserine, 537
Eseroline, 537
Essence of apple, 405
greengage, 405
melon, 405
mirbane, 407
mulberry, 405
pineapple, 405
quince, 405
Essences, 465
Essential oils, 464
Esters, 401, 447
Etching, 328
Ethal, 425
Ethane, 376, 382, 386
constitution of, 382
synthesis of, 383
Ether, 429
acetic, 283, 403
aceto-acetic, 404
compound spirit of, 432
ethyl, 429
hydrobromic, see Ethyl bromide.
nitrous, 335, 401
ozonic, 577
petroleum, 387
Ethereal vil, 432
salts, 401, 447
Ethers, 429, 447
mixed, 432
sulphur, 432
Ethiop’s mineral, 219
Ethyl, acetate, 283, 403
aceto-acetate, 404
alcohol, 419
ammonia, 508
ammonium iodide, 508
bromide, 398
butyrate, 405
carbamate, 455
chloride, 392
ether, 429
-furmic acid, 453
hydride, 386
hydrogen sulphate, 392, 420,
431
hydroxide, 417, 419
hydroxylamine, 509
iodide, 398
709
Ethyl, nitrite, 334, 401
cenathy late, 405
pelargonate, 405
sebacate, 405
series of alcohols, 417
sparteine, 539
suberate, 405
-sulphuric acid, see Ethyl
hydrogen sulphate.
Ethylamine, 508
Ethy late, sodium, 423
Ethylene, 389, 392
bromide, 393, 394
chloride, 393
diamine, 509
hydroxide, 417
iodide, 393
sulphate, 432
Ethylidene compounds, 455
lactic acid, 455
Etbylmorphine hydrochloride, 517
Ethylsul phonic acid, 428
Etymology of names of elements, 37
Eucalyptol, 467, 468
Eucalyptus oil, 468
Eucalyptus, 342
amygdalina, 468
cneorifolia, 468
dumosa, 468
globulus, 468
maculata, 468
odorata, 468
oleosu, 468
rostrata, 468
Euchlorine, 279
Eugenol, 467
Euodic aldehyde, 470
Euonymin, 507
Euonymua, 507
atropurpurens, 507
Eupatorium, 507
perfoliatum, 507
Euphorbium, 479
Euphorbon, 479
Euxanthine, 551
Evaporation, 76, 107
Everitt’s salt, 267
Exoqoninm purqa, 501
Explosion of gas, 27
Extract of malt. 493
Goulard’s, 224
Extracts, 592
Extractum Belladonne foliorum, 529
cannabia Indices, 475
ergot, 476
glycyrrhyze, 500
malti, 493
physostiqmatis, 537
rai, 223
INDEX,
FACE-ROUGE, 323
Freces, 572
Fahrenheit thermometer, 44
Pats and Oils, composition of, 439
Fats, etc,, analysis of, 681
aolid, 442
Fatty acids, 440
matter in wrine, 588
series, O74
substances, 374
Fel bovis, 549
purificatum, 49
Felspar, 337, 360
Fenchene, 415
Fennel-oil, 468
Fenugreek, 540
Fer réduit, 163
Fermentation, 420
acetic, 282, 421
alcoholic, 420, 421
nmmoniacal, 421
butyric, 453
by soluble ferments, 420
citric, 309
lactic, 351, 421
mannitic, 421
nitric, 271
putrefactive, 421]
viscous, 421
Ferments, 421
amylolytic, 549
organized, 421
pancreatic, 549
proteolytic, 549
soluble, 421
steatolytic, h49
Ferratin, 549
Ferri carbonas, 153 '
saccharatus, 152
chloridi liquor, 156
citras, 161
et ammonii cifras, 159
quantitative determi-
nation of iron in, 650
sulphas, 147
— tartras, 101, 351
et potasii fartras, 159, 161 308
quantitative determi-
nation of iron in, 650
et quinin vw citras, 161
— polubilia, 160
et atr ychnine citr (Le, 161
hydroxidum, 7 z
| maqnesii oxido, 185
hypophosphia, 329
lactas, 282 —
phowphas } swolubilia, 161
pulvis, 163
pyrophosphas solubilis, 161, 336°
]
4
| Ferri subcarbonas, 153
sulphas, 151
exsiwcatus, 151
grannlatua, 15)
teraulphatia liquor, 157, 150
Ferric neetate, 155, 284, 333, 345
aceto-nitrates, 162
ammonium sulphate, 147
benzoate, 323
cacodylate, 323
chloride, 155, et seq,
anhydrous, 155
citrate, 161
ferrocyanide, 326
gallate, 344
hippurate, 325
hydroxide, 157, 165
hydroxycarbonate, 166
iodate, 250
meconate, 332, 344
nitrate, 162
oxide, 149, 158 one
separation p cophates
and oxalates, 359
oxyacetate, 244
oxyhydroxide, 149, 157
oxyiodate, 230
oxysulphate, 152
phosphate, 161, 316
soluble, 161 |
Balts, 150, 155, et seq.
analytical reactions of, 164,
165
volumetric determination
of, 637
succinate, 340
sulphate, 157
tannate, 165, 341
thiocyanate, 165, 269, 339, 34,
valerate, 347 '
Ferricyanide, ferrous, 164, 327
potassium, S26
Ferricvanides, 326
Ferricyanogen, 14, 327
Ferrocyanide, cupric, 208, 326
ferric, 164, 326
ferrous, 1/4
potassium, 265, 326
ferrous, 267
wine, 137
-Ferrocvanides, 325
Ferrocyanogen, 164, 326
| Ferrous ammonium sulphate, 152
arsenate, 158, 176
bicarbonate, 149
bromide, 155
carbonate, 149, 152
saccharated, 152
chloride, 154
INDEX.
Ferrous chloride, anhydrous, 156 Flint glass, 338
citrates, 161 Flores zinei, 136
ferricyanide, 165 Flour, 488
ferrocyanide, 165 Flowers of sulphur, 284
hydroxide, 165 Fluidertractum belladonx radieis, 529
iodide, 154 Srangule, 498
phosphate, 153 glyeyrvhize, SOD
potassium ferrocyanide, 27 hemamelidis, 507
salts, 151, ef sey. hydrastis, 530
analytical reactions of, 164 ipecacuaniue, 535
volumetric determination | ‘‘ Fluid magnesia,” 1295
of, 651, 632, 633, 634 Fluorescein, 411
sulphate, 151 Fluoric acid, 328
sulphide, 37, 154, 164, 165 Fluoride, boron, 318
tartrate, 161 | calcium, 112, 327
Ferrwm, 39, 150 in bones, 118
reductum, 163, 650 ethyl, 328
Ferwa Fotida, 479 lithium, 104 »
Ferulaic acid, 479 silicon, 340
Fibrin, 43 sodium alnmininum, 146
ferment, 544 Fluorides, 327
insoluble, 544 Fluorine, 328
vegetable, 546 derivation of word, 38
Fibrinogen, 544 Fluor-spar, 112, 327
Ficus, 482 Fluosilicic acid, 328
elastica, 471 Fonicu! nm, 468
Fig, 482 Fenugreek, 540
Filicie acid, 444 } Foil, tin, 193
lilmarone, 444 Food, analysis of, 681
Filter, to dry, 640 Formaldehyde, 200, 448
-paper, 115, 639 Formalin, 445
Filters, 115 Formate, ammonium, 268
ashleas 639 potassium, 401
Filtrate, 118 Formates, 324
Fine gold, 198 Formic acid, 324, 448, 455
Fire-clay, 214, 338 Formica rufa, 324
-damp, 385 Formosa camphor, 472
Fir wool, 416 Formose, 448, 454
oj], 416 Formula weight, 59
Fischer's salt, 85, 142 | Formula, 59
Fisetin, 551 calculation of composition per-
Fish-poison, 511 ceut. from, 61
Fixed oils, 443 constitutional, 375
and volatile oils, difference construction of, 59
between, 443 empirical, 60, G08
Flag, bine, 507 deduction of, from conm-
Flake manna, 445 position percent., 60
white artiste’, 555 graphio, 375
toilet, 555 molecular, 60, GOS
Flame, oxidizing, 136 atructoral, 175
reducing, 136 Formy] chloride, 396
structure of, 28 Fousel-oil, eee Fusel-oil.
Flare, 442 Fowler's solution, !74
Flashing-point, 416 Foxglove, 499
Flavaspidie acid, 444 Fractional erystallization, 82, 362
Flax seed, 494 distillation, 362, 373, 410
Fleitmann's test for arsenic, 181 elutriation, 14, 362
Flexible collodion, 496 fusion,
Flint, 337 lixiviation, #), 462
712
Fractional operations, 362
precipitation, 362
sifting, #55, 362
solution, 90, S62 —
sublimation, 97, 362
Frangula, 500
Frangulin, 412, 500
Frankincense, ‘Arabian, 479
common, 478
Frarvinns ornus,
Free acids, 352
determination of, G21
Freezing-mixture, 258
French chalk, 555
turpentine, 415
Fructose, 482
Fruit essences, 405
sugars, 482
Fuchsine, 555
Fuller's earth, 338
Fulminating silver, 237
mercury, 237
Fume-cupboard, 100
Fumeroles, 318
Fuming nitric acid, 272
sulphuric acid, 293
Funnel-tubes, 26
"Fur" in water-vessels, 301
Furnace, blast, 149
Furniture of a laboratory, xv
Furze, 534
Fusel-oil, 346, 425
Fusibility of metals, Table of the,
5Y7
Fusible caleulos, 589, 191
white precipitate, 218
Fusion, fractional, 362
Fustic, 551
GARB tree, 343
Gadinine, 511
Galactose, 483, 486
Galbanum, 479
Galena, 222
argentiferous, 233
Galipea cusparia, 534
Galipine, 534
Galipot, 474
Gall of the ox, 549
Galla, 40
Gallate, ferric, Baa
Gallic acid, 340, 343, 450
Gallium, 682
Gallotannic acid, ‘B40, d59
Galla, Ale “pppoe, 340
‘English, 240
(iall-stones, 491
Galvanic test for mercury, 221
Gialvanized iron, 142
INDEX.
Gambir, 342
Gumboge, 479, 551
Indian, 470
Siam, 479
Gambogic acid, 479
Gangu, 475
Garancin, 552
| Garcinia indica, 443
Hanburii, 479
movella, 479
oil, 443
purpurea, 443
| Garcinix F pian oleum, 443
Garden thyme, 468
Garlic, cuits oil of, 427
Garnierite, 143
Gas-analysis, 344, 558
burners, 29
coul-, 297, 392, 435
for balloons, coal, 29
-lamps, 20
Gaseous volumes, law of, 51
_| Gases, analysis of, 555
collection of, 20, 21
correction of the volume of, 46,
GO4
for pressure, 47, 604
for temperature, 47, 605
diffusion of, 30
law of solubility of, in water,
23
occlusion of, by spongy paati.
num, 201
relative densities of, 48
specific gravities of, 48, 604
Gastric juice, 48
Gaultheria procumbens, 458
oil, 458
Gaultheric acid, 458
Gaultherin, 458
Gay-Lussac’s law, 46
Gelatin-producing substances, BAT
Gelatin, 547
sugar of, 550
tannate, 342 ‘
test solution, HAT
tests for, 548
vegetable, 404
Gelatinum, 547
Gelidinm cornewm, 494
(reloae, 494
Gelsemine, 535
Gelseminic acid, 535
Gelseminine, 535
(felaemium, 535
elegans, GO
nitidum, R35
Gentian-bitter, 500
Genfiana, 500
INDEX,
Gentiana lutea, 500
Gentianic acid, 500
Gentiogenin, 500
Gentiopicriu, 500
Gentisic acid, 500
Gentisin, 500
Geraniol, 469
Geranium maculatum, 343
oil, 463
German silver, 132, 143
yeast, 420
Ghatti, 494
Gin, 422
Gingelly oil, 444
Ginger-grass oil, 468, 469
vil, 471
oleoresin, 478
Gingerol, 531
Girdwood and Rogers’s method for
detecting strychnine, 566
Glacial acetic acid, 283
phosphoric acid, 314
Glance, bismuth, 227
Glass, 140, 338
liquor, 339
of antimony, 186
rods, 75
soluble, 339
tubes, to bend, 21
to cut, 21
to draw out, 116
water-, 338
Glauber’s salt, 253
Globulins, 546
Glucinum, 682
(:lucose, 420, 482
Glucoses, 481
Glucosides, 496
Glue, 547
Glutaric acid, 463
Gluten, 479
Glutin, 479, 547
Glyceric acid, 455
Glycerin, 437
tests for, 438
Glycerinum, 437
Glycerites, 592
Glyceritum acidi tannici, 341, 438
amyli, 438
boroglycerini, 319
ferri, quinine, et strychnine,
phosphatum, 438
hydrastis, 438
phenolis, 433, 438
Glycerol, 437
Glycerose, 481
Glycery], 437
borate, 320
caproate, 442
713
Glyceryl] caprylate, 442
‘hydroxide, 417, 437
hydroxyoxalate, 324
laurate, 442
myristate, 442
nitrate, 438
oleate, 439
palmitate, 442
ricinoleate, 444
Trutate, 442
tristearate, 439
Glycocholates, 550
Glycine, 550
Glycocoll, 550
Glycogen, 491
Glycol, 436
-aldehyde, 446
oxidation of, 461
trichlorbutylidene, 453
trichlorethylidene, 453
Glycollic acid, 446, 455
Glycols, 435
aromatic, 436
Glycuronic acid, 577
Glycyrrhetin, 500
Glycyrrhiza, 485, 500
Glycyrrhizate ammonium, 501
calcium, 501
Glycyrrhizic acid, 500
Glycyrrhizin, 500
Glyoxal, 446
Glyoxylic acid, 455
series, 455
Gmelin’s test for bile, 550
Gnoscopine, 517
(ioa powder, 412
Gold, 197
analytical reactions of, 198
chloride, 198, 570
test solution, 198
coin, 197
derivation of word, 38
dust, 197
earth, 551
fine, 198
jewellers’, 197
leaf, 197
mosaic, 196
mystery, 197
ochre, 551
perchloride, see Auric chloride.
sodium thiosulphate, 295
sulphide, 198
yellow, 551
Golden sea), 530
syrup, 485
(ivoseberry, 482
(foasypi corter, 5OT
Gossypium purificatum, 495
714 INDEX,
Gothite, 149 Guanine, 571
Groulard's cerate, 224 Guano, 346
extract, 223 “Guarana, 531
water, 224 Guaranuine, 531. See Caffeine
Graham's dialytic process, G50 (auaga, 475
law of diffusiun, 30 Guilandina bonducella, S07
Grain tin, 199 (iuinea grains, 469
Grains of paradise, 469 —Gulancha tinespora, 507
Gramme, 41 | Gulose, 483
molecule, 55 (7um, 121, 494
volume, G0 -acacia, 121, 494
Granatum, 342, 537 -arabic, 121, 494
Granulated phosphorus, 312 Benjamin, 321, 456
tim, 193 benzoin, 456
zinc, 25 British, 492
Granulose, 489 cherry-tree, 494
Grape, 482 Indian, 494
juice, 305 red, 468
sugar, 305, 482 resins, 479
Grapes, dried, 305 tragacanth, 121, 494
sugar in, 482 | Gummate, calcium, 121
Graphic formule, 375 lead, 121
Graphite, 36 | Gummic acid, 494
Grass oils (3), 468, 469, 471 Gunj, 501
Gravel, 582 ' Gunjah, 475
Gravimetric quantitative analysis, | Gun-cottoy, 495
LS is) | -metal, 193
Gravity, specific, 47, 509, et seq. Gunpowder, 275
Gray powder, 210 Gurjon Balsam, 477
Green, Brunswick, 184 Gutta Percha, 471
Chinese, 555 Gutzeit's test for ursenic, 182
copperas, 152 (rynocardia odorata, 444
emerald, 555 oil, 444
hellebore, 501 Gypsum, 112, 200
iron iodide, 154
pigments, 555 H2MATEIN, 553
Scheele’s, 184 Hematite, brown, 149
Schweinfurth, 184 red, 149
ultramarine, 555 Hmwmatoporphyrin, 574
vitriol, 152, 202 } Heematoxylin, 553
Greengage essence, 405 Hematocylon, 342, 553
(iriess's reagent, 335 Hemoglobin, 46
(iriffith’s mixture, 153 Halide, 391
Grindelia, 535 _— | Halogens, 265
robusta, 535 Halwid salts, 265
Grinde line, 535 Hamamelidia cortex, 507
Ground-nut oil, 444 folia, W7
Group: tests, 242 Humamelia virgmica, 507
Guaincin, 501 Hambro’ blue, 553
Guaiacol, 4 a3 Hard soap, 441
carbonate, 433 Hardness of water, 301
Guaiac ‘olis carbonas, 433 Hart's test, 262
Gnas aconic acid, 501 Hashish, 475
Guaiae “tm, 501 Haw, black, 507
offic inale, 501 Hwat, atomic, 5
resin of, 476, 501 Heavy carburetted hydrogen, 292
Guniare tic ae id, BOL nagnesia, 126
CGuaiaretin, 5OL | magnesium carbonate, 124
Guaiaretinic acid, fl oxide, 125
INDEX,
Heavy spar, 109, 290
white, 100, 553
Heetare, 41
Hedeoma, 460
pulegioides, 460
Helenin, 468
Heliotrope, 503
Helium, 29
Hellebore, black, 501
green, 501, 536
white, 536
American, 536
Helleborein, 501
Helleborin, 501
Helleborus niger, DOL
viridis, SOL
Heller's test for albumin in urine,
a7
Hemidesmic acid, 325
Hemlock, 468, 533
fruit, 533
leaves, 533
Hemp, Canadian, 507
Indian, 474
Hempseed calculi, 591
Heubane, 535
Henry and Dalton's laws, 23
Heptane, 386
Heptoic aldehyde, 465
Heptylene, 302
Herapathite, 520
Heroin, 516
Hesperidene, 466
Hesperidin, 507
Hevea, 471
Hexabasic acids, 463
Hexabromobengene, 407
Hexachlorobenzene, 407
Hexahydrie alcohola, 445
Hexahydrobenzene, 411
Hexa-hydro-pyridine, 538
Hexamethylenamina, 445
Hexamethylenamine, 448
Hexamethylenetetramine, 418
Hexane, 386
Hexylene, 392
Hippuric acid, $25, 583
Hips, 484
Hoffmann's anodyne, 432
Hoffuer’s blue, 553
Hofmann’s method for detection of
arsenic and antimony, 203
Hollway's smelting process, 205
HTomatropine hydrobromidum, [28
Homatropine, 528
hydrobromide, 528
a-Homochelidonine, 538
§- —, AAs
Homologons series, 340
Homologues, 380
general formule for, 380
| Homology, 380
Homonataloin, 413
Homopterocarpin, 552
| Homoquinine, 525
Homotartaric acid, 463
Honey, 454
hborux, 319
clarified, 484
Honeydew, 486
Hop, 478, 536
bitter, 478
essential oil of, 478
Horehound, 507
Horse-chestnut, 535
Horseradish oil, 466
Houzeau's test for ozone, 261
Huile de Cade, 478
Humulus, 478, 536
lupulus, 478, 536
Hydrargyri chloridum corrosovium,
214
mite, 215
iodidum florum, 210
rubrum, 211
oxidum flarwm, 216
rubrum, 216
sulphuretum cum sulphure, 219
Hydrargyrum, 39, 209
aonmoniafum, 215
coum ereta, 210
Hydrastine, 530
acid tartrate, 530
Hydraatia, 530
canadenma, 530
Hydrate, see Hydroxide,
butyl chloral, 453
chlorine, 254
Hydration, 440
Hydraulic cement 338
Hydrazine, 510
Hydrasobenzene, 407
Hydride, antimony, 19]
euprous, 330
ethyl, 386
methyl, 385
silicon, S39
Hydriodie acid, 258, 26°
dilute, 260
Hydrium, 26
Hydrobromic acid, 255
dilute, 257
preparation, Marshall's
method, 256
Seott's method, 256
Hydrocarbons, 375
acetylene series, Of4
authracene series, 411
716
H
“cracking "’ of, 373
dibydroxyl derivatives, 435
monohydroxy! derivatives, 417
napthalene series, 411
normal paraflin, 381
olefine series, 389
parailin series, 376
polybydroxyl derivatives, 445°
suturated, 376
series of, 376
terpene series, 415
trihydroxyl derivatives, 437
unsaturated,
Hydrochloric acid, 35, 252
analytical reactions of, 255
autidote, 255
commercial, 253
dilute, 253
in organic mixtures, detec-
tion of, 565
volumetric determination
of, 6235
Hydrochloride, apomorphine, 517
morphine, 513
quinine, 519
Hydrocinchonidine, 523
Hydrocotarnine, 517
Hydrocotoin, 499
Hydrocotyle asiatica, 07
Hydrocotyles folia, 507
Hydrocyanic acid, 265, 326
analytical reactions of, 268
antidotes to, 270
diluted, 267
from bitter almond and
cherry laurel, 268, 497
in organic mixtures, detec-
‘tion of, 564
in the blood, 269 ee
Schénbein's test for, 270
volu a determination
of, G25
Hydrofe nelevanié acid, 326
Hyd roferrocyanic acid, 325
Hyd rofluoric acid, 327
Hydrogen, 25
acetate, benzoate, borate, chlo-
ride, nitrate, sulphate, etc., |
see the respective acids, acetic,
be nzoic, ete.
antimonide, 191
antimoniuretted, 191
arsenide, 180
“arse *niuretted, 180
combination with chlorine, 35
combustion of, 26
derivation of word, §
dioxide, 109
INDEX,
bons, benzene series, 406 | Hydrogen, explosion of, pore
heavy ca
in artificial eh ehdia 2
light carburetted, J85
lightness of, 29
phosphides, 328
phosphuretted, 328
preparation of, 25
properties of, 24, 29
quantitative ‘determination of,
in organic compounds, 670,
et seq.
salts, 65
siliciuretted, 339
sulphide, 100, 154, 284
oxidation, of, 101
sulphuretted, 100, 284
test for arsenic, 179
used for balloons, 20
weight compared with air, 29
weight of 1 litre, 606
weight of 100 cubie inches, G06
Hydrogeniwm 25
Hydrolysis, 440, 486
Hydrometers, 601
| Hydroquinine, 523
| Hydroquinone, 436,
Hydrosulphide, ammon
ssereinge~ 287
518
onium, 99, 237
sodium
Hy dreoulphides, 287
analytical reactions of, 257
Hydrosu)phuric acid, 264
Hydrous butyl chloral, 453
salts, 90
Hydroxide, iawn 146, 148
ammonium, 94
barium, 109
bismuth, 231
cadmium, 235
calcium, 114
chromic, 169
eupric, 207
ethyl, 419
ferric, 157
ferrous, 165
manganese, 140
methyl, 418
nickel, 144
pases 72
sodium, 86
stannous, 196
strontium, lil
| Hydroxides, bases are probably, (4
composition of, 64, 72
identified, 361
of the hydrocarbon rad ients,
417
INDEX, “7
Hydroxyacetic acid, 455, 457 Hyposulphurous acid, 296
Hydroxybenzoic acid, ortho-, 457 Hypothesis, Avogadro’s. 53
aldehyde, ortho-, 458
Hydroxybenzy! alcohol, 437 -Ic, meaning of, 77, 81, 151
Hpdroxybutyric acid, 455 Icacin, 478
Hydroxycaproic, 455 Iceland moss, 323, 491
Hydruxycaprylic acid, 455 -ide, meaning of, 81
Hydroxycarbonate, copper, 205 Igasurine, 525
lead, 223, 226, Ignition, 107
Magnesium, 124, 302 . Illicium verum, 466
zinc, 134 Illuminating agents, analysis of, 681
Hydroxyformic acid, 455 Imidazoic acid, 510
Hydroxyl, 273, 282 Imino-bases, 509
Hydroxylamine, 509 Incense, 480
hydrochloride, 509 Incineration, 107
Hydroxy-lauric acid, 455 ~ of filters in quantitative analy-
Hydroxy - propane - tricarboxylic sis, 639
acid, 462 Indelible ink, 236
Hydroxypropionic acid, 455 Indestructibility of matter, 17
Hydroxysuccinic acid, 461 India senna, 578
Hydroxytoluic acid, 457 Indian azadirach, 507
Hydroxyvaleric acid, 455 gamboge, 479
Hygiene, 18 gum, 494
Hygrophila, 507 hemp, 474
apinosa, 507 ink, 555
Hyoscine, 535 ipecacuanha, 534
hydrobromide, 535 licorice, 501
Hyoscine hydrobromidum, 535 melissa oil, 471
Hyoscyaminz hydrobromidium, 535 mustard, 427
sulphas, 535 pennywort, 507
Hyoscyamine, 527, 535 red, 552
hydrobromide, 535 ° yellow, 551
sulphate, 535 India-rubber, 471
Hyoscyamus, 535 vulcanized, 471
niger, 535 Indican, 553
Hyper-, meaning of, 155 Indicator, 611
Hypnone, 464 Indiglucin, 553
Hypo-, meaning of, prefix, 330 Indigo, 276, 553
‘* Hypo,"’ 204 artificial, 554
use of, in photography, 295 blue, 276
Hypobromites, 257 reduced, 553
Hypochloride, sulphur, 287 sulphate, 276
Hypochlorite, calcium, 119 test solution, 276
sodium, 91 -white, 553
Hy pochlorites, 276 wild, 529
Hypochlorous acid, 120, 276 Indigofera, 553
Hypogmine, 444 Indigogen, 553
Hypophosphite ammonium, 329 Indigotin, 554
barium, 329 disulphonic acid, 276
calcium, 320 Indium, 682
ferric, 329 Infusible white precipitate, 219
Manganese, 138, 329 Infusions, 592
potassium, 329 Infusorial earth, 339, 546
quinine, 329 Ink, black, 165, 341, 555
sodium, 329 indelible, 2386
Hypophosphites, 328 Indian, 555
Hypophosphoric acid, 336 invisible, 142
Hypophosphorous acid, 328, 336, 337 marking, 236
Hyposulphites, see Thiosulphates. printer's, 555
718 INDEX,
Ink, sympathetic, 145 Iodine, moisture in, 660)
Inosite, 483 : molecular formula of, 259
Insecticide, 477 solution of, 259
Insoluble substances, analysis of, specific gravity, 264
S60 | standard solution of, 628
Introduction, 17 tincture of, 259
Inula Helenium, 468, 491 volumetric determination of,
Inutilenin, 491 636
Inulic anhydride, 468 water, 259
Inulin, 491 Todo-salicylic acid, 458
Tnulol, 468 lodoform, 401, 444
Invertase, 421) | fodoformum, 401
Inverted sugar, 452 Jodol, 511
Invisible ink, 142 lodolum, 511
Jodal, 453 lodopyrrol, 511
lodate, ferric, 280 Todum, 255
potassium, 80, 250 Ionization, 363
silver, 280 Tons, 363
Todates, 258, 280 Tpecacuanha, 534
lodic acid, 260, 280 wine, 534
Iodide, ammonium, $8 Tpecacuunhie acid, 534
antimonious, 165 Tpomea hederacea, 50
arsenous, 173 . orizabensia, 501
bismuth, 229 purga, 501
and potassium, 570 simulans, 52
cadmium, 232 turpethum, 213, 502
cuprous, 206, 208, 261 [ridin, 507
cyanogen 259 Iridium, 199, 201, G82
dimercuri-ammonium, 210 chloride, 470
ethyl, 398 Tris florentina, 469
ferrous, 14 versicolor, HOT
hydrogen, 259 Irish moss, 494
iron, 37, 154 Irisin, SOT
lead, 224, 263 tron, 149
mercuric, 210, ef seg., 218, 264 noetute, 158, 283, 335, 345
mercurous, 210, 220 ucetonitrates, Liz
nitrogen, 260, alum, 147
potassium, 79, 260 } nmmonium citrate, 150
detection of iodate in, 80 and ammonitvtm tartrate,
_ mercuric, 220 161, 308
silver, 237, 260, 280 potassium tartrate, 159,
sodium, 91 161, 308
starch, 80, 260, 480 analytical reactions of, 164
sulphur, 859, 287 and quinine citrate, soluble,
zine, 134 . 161
Todides, 258, arsenate, 158, 176, 185
unalytical reactions of, 260 ursenio-sulphide, 173
of mx mercury, 210, et we - bromide, 155
quantitative de termination of, carbonate, 152
627, 660 ; cast-, 150
se paration of, from bromides: chlorides, 154, 155, et seg.
_ and e hlor ides, 4, 261 compounds, Domenclature of,
Iodine, ‘ $6, 25 8 | 149
atomic we ight, g ono : derivation of word, 38
its an: alogy to ec chlorine and bro- | dlete ction of, in presenoe of
_ mine, 264 ie Huminium ond chrom inn,
deriv ation of word, 38 a. ~ 70, 171
detection of, in mere nrie iodide, ferrocyanides, 165, 326
249 . rulvanized, 132
INDEX,
Iron, gravimetric determination of, | Isinglass, Japanese, 494
Gay Iso, meaning of, 501
hydroxide, 157 Isoamy! hydride, 386
in official compounds, determi- | Isobarbaloin, 413
nation of, 649 Isobutane, 386
jodate, 280 Isoheptoie acid, 469
iodide, 37, 14 lsomeric substances, 379
maltosate, 153 lsomerides, 379
manufacture of, 140 Isomerism, 379, 300
meconate, 332 Isomers, 379
nitrate, 162 [somorphous bodies, 133
ore, magnetic, 119 Ieonandra gutta, 471
needle, 149 Isonitriles, 447
spathic, 149 Isopentane, 386
specular, 149 | | Isophthalic acid, 462
oxide magnetic, 149 Isoprene, 475
determination of iron | Lsopropylacetic acid, 453
in, 635 Isopropy! iodide, 383
red, 158 - Isorottlerin, 477
oxyhydroxides, 149, 157 Iso-thiocyanate, acrinyl], 427
oxyiodate, 280 allyl, 427, 466, 470
oxysulphate, 152 Iso-valerate, zine, 136
perchloride, see Ferric chloride | Iso-valeric acid, 347, 453
persulphate, see Ferric sulphate | Ispaghul, 495
phosphates, 153, 316 -ite, meaning of, 81
pill, 153 Ivory-black, 555
potassium tartrate, 161
protosulphate, 151 JABORIDINE, 537
pyrites, 149, 254 | Jaborine, 537
quantitative determination of, | Jalap, Indian substitute for, 213
gravimetric, (49 Mexican male, 501, 505
volumetric, 631, 637 resin, 476, 501, 502
red oxide of, 158 Tampico, 502
reduced, 162 | true, 501
Trust, 150 Jalapa, AP
saccharated carbonate, 152 Jalapin, 501
volumetric determina- | Jalapurgin, 501
tion of, 632 Japaconitine, 527
salts, nomenclature of, 150 Japanese belladonna, 529
scale, compounds of, 158 isinglass, 44
separation of, from aluminium | Jasmine, yellow, 535
and chromium, 170, 171 | Jawne brilliant, 232
from phosphates and oxa- | Jelly, vegetable, 414
lates, 350 Jequeritin, 501
amlio-citrate, 161 Joquerity or jequirity, 501, 547
sucrate, 152 | Jequerityzymase, DOL
sulphate, 157 Jervine, 536
sulphide, 7, 154, 165 Jeweller’s gold, 197
turtrate, 161 Juniper camphor, 460
thiocyanate, 165, 345 oll, 460
wine of, 161 ) tar oil, 478
hitter, 161 Juniperus oxycedrus, ATR
. wrought, 150 sabhina, 470
Ironstone, clay, 149
black band, 149 KAtnire. 71
¢hrome, 146 Kairine, 512, 923
Isaconitine, 526 Kairoline, 523
Isatropyl-cocaine, 532 Kaladana resin, 502
lsinglass, 547 Kali, 30
720
Kaliwm, 39
Kamala, 477
Kano, 342
Kaolin, 338
Kaolinum, 338
Kariyat, 07
Kava, 507
Kave rhizome, 507
Kelp, 250
Kermes, 150
mineral, 1&0
Ketone chloroform, 399
Ketones, 465
Ketoses, 451
Kieselgubr, 545
Kieserite, 123
Kiln, 114
Kinates, see Quinates.
Kinetic theory, 30
King’s blue, 553
yellow, 551
Kino, 342
Australian, 342
Kinone, see Quinone.
Kjeldahl's process, 674
Klunge's reaction, 413
Kokum butter, 443
Kola-nut, 530, 539
Kosin, 476
Koussin, 476
Kousso, 476
Krameria, 342
Krypton, 32, 33
Kunch, 601
LABORATORY furniture, xv.
Laburnum, 534.
dye, 553
Lactams, 504
Lactate, calcium, 331
Lactates, 331
Lactic acid, 351, 455
volumetric
of, 623
series of acids, 455
relations vy acetic
glyoxylic series, 456
L actims, ! 504
‘Lacometer, . B45 %, GOL
Luc ctone, 481, 504
Lactone ns, 504
Lac ‘tophospl hate, calei ium, syrup of,
= ae 1) Sol
‘Lac tose, 486
Lactuea, HOT
Lactnoar inn OT
Lac tucin, OT
Lacdlies’ slipper, HT
determination
and
INDEX,
Le vorotation, 306
Le votartaric acid, 306
Levulose, 452
Lakes, 1458, 555
Lam Py self-lighting,
1
-black, 297, 555
Lana philosophica, 136
Lanoline, 440, 441
| Lanthanum, 171, 172, 682
Lanthopine, 517
| Lapis lazuli, 554
Lappa, 507
officinalis, 507
| Larch bark, 342
Lard, 442
benzoinated, 442
purified, 442
Larix europwa, 342
Larixin, 342
Lurixinic acid, 342
Laudanine, 517
Landanosine, 517
Laughing-gas, {7
Laurate, glyceryl, 442
Laurel-camphor, 472
Lauric acid, 442
aldehyde, 470
Laurocerast hag 4
Lavandula xpica, 4
Lavender flowers, il of, 469
water, 405
Law, Boyle's, 46
Charles's, 46
Dulong and Petit’s, 58
Gay Lussac’s, 46
Graham's, 30
Heury and Dalton’s, 23
of constant proportions, 51
of diffusion bt guses, Ol)
of indestruetibility of nmther,
17
of multiple proportions, 51, 275,
296
of solubility of gases in liquids,
23
Periodic, 364
| Laws of chemies! combination by
weight, 50, 51
of chemical combination by
volume, 51
| one plant
acetate, 223
volumetric determination
of, fi57
analytical reactions of, 225
antidotes af,
black-, 208
curbonabe, 226
INDEX.
Lead, chloride, 225
chromates, 167, 169, 226
cyanate, 324
derivation of word, 33
detection of, in organic mix-
tures, 561, 562
dioxide, see ‘Lead peroxide.
gravimetric determination of,
656
gummuate, 121
hydroxide, 226
hydroxy-carbunate, 223, 226
iodide, 224, 264
malate, 332
nitrate, 224
oleate, 224
oxide, 222
oxyacetate, 223
oxychromate, 167
peroxide, 222, 224
-plaster, 225
puce-colored oxide, or peroxide,
sh)
pyrophorus, 163
red, 222, 552
shot, 222
subacetate, 223
sugar of, 223
sulphate, 226
sulphide, 225
native, 222
test for, in water, 225
tree, 237
white, 23,
Leadstone, 149
Leaf, gold, 197
-green, ood
[eather, 341
Leblanc process, 254
Lecanora, 5514
Lecith-albumins, 543
Lecithin, 510
Lecithins, 543
Lees, 305
Legumin, 546
Lemon-chrome, 226
grass oil, 471
juice, 308, 310
determination of mineral
acids in, 664
oil, 466
Length, unit of, 40
Lentisk tree, 476
Lepidolite, 103
Leptandrin, 507
Leptandra, AZ
Lettuce, 535
Leucie acid, 455
Leucine, 510, 583
46
and
72]
Leucomaines, 510
Levisticum, 479
Levuluse, 482
Lichen blue, 554
sugar, 445
Lichenin, 491
| Lichenstearic acid, 323
| Licorice, 500
Indian, 501
root, 485
Spanish, 500
sugar, 485, 501
Light, carburetted hydrogen, 385
Lignin, 495 °
Lignite, 339
Lime, bisulphite, 289
carbonate, see Calcium carbon-
ate.
caustic, 113
chloride, 119
chlorinated, 119
juice, 308, 310
determination of mineral
acids in, 664
-kiln, 114
-oil, 466
quick-, 113
slaked, 114
sulphurated, 120
syrup of, 114
water, 114
Limestone, 112
magnesian, 123
mountain-, 123
Limonenes, 415
Limonis corter, 466
saccus, 310
Linaly] acetate, 467
Linamarin, 498
Linalool, 469
Liniments, 502
Lintmentum ammoniz, 441
belladonna, 529
caleia, 441
camphora, 473
sapontas, 441
mollis, 441
Linkage of atoms, 375, 410
Linoleine, 443
Linoxyn, 443
Linseed, 443,
ground, 443
-oil, 443
boiled, 443
-tea, 494
Linum, 443, 494
Lipase, 549
Lipuria, 58s
Liquid, camphor, 472
722 INDEX.
Liquid petrolatum, 388 Litmus, 99, 554
Liquidamber orientalis, 460 paper, 99
Liquids, specific gravity of, 599 test solution, 99, 620
ofticial specific gravities of, 600 | Litre, 41
Liquor, acidt arsenosi, 174 relation of, to liquid gallon, 42
anmonit acetatis, 96 Liver of sulphur, 73
arsent et hydrargyrt todtdi, 173
calcis, 114
chlori compositus, 254
Serrt et ammonti acetatis, 650
determination of
iron in, 630
chloridi, 156
determination of
iron in, 650
subsulphatis, determination
of iron in, 650
tersulphatis, 156, 159
determination of iron
in, 650
Sormaldehydi, 448
hydrarqyrit nitratis, 212
iodi compositus, 259
magnesti citratis, 126
plumbi subacetatis, 223
dilutus, 224
potassia hydroxidi, 72
specific gravity of, 601
tu prepare, 72
potassii arsenitis, 174
sods chlorinatxy, 91, 277
sodit arsenitis, 176
zinci chloridi, 134
Liquorice, see Licorice.
List ofapparatus, xiv.
chemical substances, xvi.
reagents, XV.
Litharge, 222
Lithates, 346
Lithii benzoas, 104, 323
bromidum, 104
carbonas, 103
citras, 104
effervescens, 104
salicylas, 104
Lithie acid, 346
Lithium, 103
analytical reactions of, 101
benzoate, 323
bromide, 104
carbonate, 103
chloroplatinate, 104
citrate, 104
derivation of word, 38
flame, 105
fluoride, 104
salicvlas, 104
silicate, 10-4
urate, 104
Lixiviation, 89
fractional, 90, 362
Loadstone, 149
Luaf sugar, 484
Lobelia, 536
tnflata, 536
Lohbeline, 536
Lodestone, 149
Loganetin, 502
Loganin, 502
Logwood, 342, 553
solution of, bleached by chlo-
rine, 35
Lokas, 554
Long pepper, 538
Looking-glasses, 193
Louisa-blue, 554
Lovage, 479
Lozenge, see Trochischt.
Lozenges, 592
potassium chlorate, 278
sodium bicarbonate, 87, 89
Lucifers, 30
Lump-sugar, 484
Lunar-caustic, 235
Lupulin, oleo-resin of, 478
Lupuline, 536
Lupulinic acid, 478
Lupulinim, 478, 536
Lupulus, 507
Luteolin, 552
Lutidine, 512
Luting, fire-clay, 214
Lycopodine, 444
Lycopodium, 444
clavatum, 444
Lyddite, 435
MACE, fixed oil of, 442
volatile oil of, 469
Macleya cordata, 538
Macleyine, 538
Madder, 411, 552
Mayenta, 555
Magnesia, 1:25
alba, 302
calcined, 126
fluid, 125
heavy, 126
mixture, 315 .
Magnesian limestone, 123
Maanesii carbonas, 124
oridum, 126, 185
SS
INDEX,
Magnestt oridum ponderosum, 126
sulphas, 123
effervescens, 124
Magnesite, 123
Magnesium, 123
aluminite, 146
ammonium arsenate, 127
phosphate, 126, 315
sulphate, 667
analytical reactions of, 126
basic carbonate, 301
carbonate, 123, 124, 126, 301
Pattinson’s process, 124
chloride, 123
citrate, 126
copaivate, 477
derivation of word, 38
detection of, in presence of
barium, strontium, and cal-
cium, 128
hydroxycarbonate, 124
oxide, 125
phosphate, in bones, 117
quantitative determination of,
64
separation from barium, stron-
tium, and calcium, 128
silicate, 337, 555
silicide, 339
sulphate, 123, 290
use in Marsh’s test, 181
Magnetic iron ore, 149
Magnolia, 507
Magpie test for mercury, 221
Maize starch, 487, 490 (fig.).
Malachite, 205
Malate, atropine (acid), 527
calcium,
ead, 332
nicotine, 537
potassium, 332
Malates, 332
Male fern, oil of, 444
Malic acid, 332, 461, 463
series of acids, 461
Mallow tea, 494
Malonic acid, 463
Malt, 488, 493
extract, 493
substitutes, 483
vinegar, 282
Maltosate, iron, 153
Maltose, 483, 484
Maltum, 493
Mandelic acid, 497
tropine ester of, 528
Manganate, potassium, 81, 139
sodium, 139
Manganese, 138
723
Manganese, analytical reactions of,
138, et seq.
black oxide, 138, 254
borate, 140
Crums’s test for, 141
derivation of word, 39
dioxide, precipitated, 138
hypophosphite, 138, 329
Marshall’s test for, 141
quantitative analysis of black
oxide, 648
separation of, from nickel, co-
balt. and zinc, 140
sulphate, 138, 254
Mangani dioxidum precipitatum, 138
hypophosphis 138, 329
sulphas, 138
Manganite, 139
Manganous chloride, 138
hydroxide, 140
sulphate, 138, 254
sulphide, 140
Mangosteen oil, 443
Manihot, starch of, 490 (fig.)
Manna, 445
Mannite, 445
Mannitol, 445
Mannonic acid, 445
Mannosaccharic acid, 486
Mannose, 445, 483, 486
Manures, analysis of, 681
Maranta, starch of, 490 (fig.)
Maraschino, 422
Marble, 112
Margarine, 442
Margosa, 507
Marigold, 507
Marine soap, 443
Marking ink, 236
Marl, 146
Marrubein, 507
Marrubium, 507
Marseilles soap, 441
Marshall's method for preparing
hydrobromic acid, 256
test for manganese, 141
Marsh-gas, 385
series, 376
Marshmallow, 494
Marsh’s test for arsenic, 179, 182
Mass, unit of, 41
Massa hydrargyri, 210
Massicot, 222
Maatic, 476
Mastichic acid, 476
Masticin, 476
Maté, 530
Matic folia, 507
Matico, 507
724
Matricaria chamomilla, 466
Matter, indestructible, 17
Mauve, 498, 555
Maximum density point of wuter,
A7
May-apple, 476
Mayer's reagent, 570, 616
Meadow-sweet, 455, 503
oil of, 458, 503
Measurement of atmospheric pres-
sure, 44
of temperature, 43
Measures, 40, ef seq.
Mechanical mixture and chemical
combination, 37, 49
Meconate, calcium, 332, 514
ferric, 332, 515
morphine, 513
Meconates, 333
distinction
and thicceyanates, 333, 345
Meconic acid, 332, 513
Meconidine, 517
Meconin, 517 —
Meconoisin, 517)
Medicated waters, 465
Meerschaum, 337
Mel, 484, 485
depuratum, 454
Melalenca leneadendron, 467
Melam, 345
Melasses, 485
Melegueta pepper, 460
Melezitose, 486
Melia azadirachta, 507
Melissa oil, 471
Melissic acid, 453, 455
Melissyl alcohol, 426
palmitate, 426
Melitose, 486,
Melitriose, 486
Mellitic acid, 463
Mellon, 345 .
Melou essence, 405
_ pumpkin: seeds, 507
Melting- -point, determination of,
{ ons
Me Iting-points of metals, 597
~ of official substances, 5YT
Memoranda, analytical, 246, 350
Men mniseus, 613
Menispermun canadense, 530
Me nthe arr ensis, 460
piperita, 469
pulegium, 469
oie Bod
Menthol,
Me minnie. aD
Mereuptans, 428
4Go
of, from acetates
INDEX,
Mercuria! ointment, 210
plaster, 210
Mercurialine, 509
Mereurialis annua, S00
nia, 509
| Mercuri-ammonium chloride, 218
Mercuric chloride, 215
chlorosulphide, 219
eyanide, 266
iodide, 210, et seq., 264
nitrate, 212
oleate, 440
oxide, 216
oxychloride, 276
oxynitrates, 212
oxysulphate, 213
phenate, 434
potassium iodide test solution,
616
salts, analytical reactions of,
218
avtshake 212
culphide, 215, 219
thiocyanate, Ho
| Mercuros-ammonium chloride, 220
Mercurous acetate, 264
chloride, 214, 215, 221
chromate, 169, 221
iodide, 210, et seq., 220
nitrate, 212
oxide, 217
sults, analytical reactions of,
219
sulphate, 213
| ORCETY, 200
ammoninted, 218
ammonio-chloride, 918
analytical reactions of, 217
antidote ta, 221
basic sulphate, 212
bichloride, 214
black oxide, 217
chlorides, 213
copper test for, 217
derivation of word, 39
detection of, Im organic mix-
tores, 56]
formula of molecule, 209
fulminuate,
calvanic test for, 220
iodides, 210, et a
magpie test for, 221
medicinal compounds of, 208
molecular weight of, 209
native sulphide, 200
nitrates, 212
nomenclature a 209
oleate, 440
INDEX,
Mercury, oxides, 210, 216, 217
oxylitrates, 212
oxysulphate, 213
perchloride, see Mercurie chlo-
ride.
persulphate, see Morenric sul-
phate,
plaster, 210
quantitative determination of,
654
red iodide, 211
oxide, 216
sulphide, 219
subchloride, see
chloride.
sulphate, 212
sulphide, 200, 219
yellow oxide, 216
Mesitvlene, 406
Mesoxalic acid, 463
Meta, meanings of, etc., 73, 410
Metabisulphites, 289
Metaborate, barium, 320
calcium, 320
silver, 320
sodium, 320
Metaboric acid, 318
Metachloral, 451
Metacinoamein, 460
Metacopaivie acid, 477
Meta-dihydroxybenzene, 436
Metagummate calciom, 494
Metaldehyde, 440)
Metallic elements, 20
quantitative determination of,
638
radical, 65
rudicals, 71
Metals, 1!)
table of
597
Metamerides, J80
Metumerism, 380
Metamers, S80
Metantimonate, sodium, 129
Metantimonic acid, 158
Metantimonite, sodium, 190
Meta-phenylene-«liamine, 511
Metaphosphate, silver, 333
Metaphosphates, 35
Metaphosphoric acid, 312, 314, 335,
oT
Metaphthalic acid, 462
Metarsenites, 174, 153
Metastannate, sodiam, 195
Metastannic acid, 105
Metastyrol, 400
Metathesis, 73
Meta-thiantimonite, sodium, 1)
Mercurous
the fusibility of,
Moeta-thiarsenites, 182
Metavanadates, 318
Methane, 376, 385
series, 376
substitution products of, 305
Metheny! chloride, 396
Methoxyeatechol, 321
Methyl! alcohol, 418
detected in presence of
ethyl alcohol, 419
oxidation of, 325
Methylal, 450
Methylamine, 509
Methylated spirit, 419
Methyl-arbutin, 408
-arsonic acid, 323
-benzene, 406, 408
bromide, 398
~arbinel, 419
chloride, 398
-conline, 533
cupreine, 523
ethyl, 386
amylamine, 500
propyl-isobuty] chloride,
Aa
formie acid, 445
glycocoll, 510
group, 400
hydride, 385
hydroxide, 415
iodide, 208
-morphine, 516
nonyl-ketone, 464, 470
-protocatechuic aldehyde, 450
pyridine, 512
salicylas, 458
salicylate, 458
-theobromine, 540, 539
Methylene blue, 556
chloride, 206
Methylthioninwe hydrochloridum, 556
Methylthionine hydrochloride, 5M
Metre, 40
relation of, to inches, 42
Metric system, 40
weights and moasures of, 43
Meum, 479)
Mexican male jalap, 501
Merereon, 476
Mezerenm, 476, 499
Mica, 146
Micococens urew, S74
Microcosmic salt, 357
Microscopic examination of arinary
sediments, 55
Microscopy of starches, 480
Milk, S44, M45
-polson, 511, 570
726
Milk-cordling ferment, 544
of sulphur, 285
sugar, 486
Millon’'s reaction, 548
reagent, 545
Mimetesite, 318
Mimotannic acid, 342
Mineral acid, detection of, in or-
ganic mixtures, 563
Mineral chameleon, 139
Ethiop's, 219
kermes, 159
purple, 552
rouge, 158, 553
turpeth, 213
salts, general analysis of, 34,
et seq.
Minerals, special, analysis of, G81
Minium, 222
Mint, 469
oil, 469
Mirbane, essence of, 407
Mishmi bitter, 530
Mispickel, 173
Mistura ferri composita, 153
Mitigated silver nitrate, 236
Mixed ethers, 432
Mixture, definition of, 50
different from chemical combi-
nation, 37, 50
Mixtures, 592
Moist sugar, 464
Moisture in iodine, determination
of, G60
Molasses, 485
Molecular, arsenic, 173
formula, 60, GOS
mereury, 200
phosphorus, 313
sulphur, 285
weight necessary in assigning
molecular formula, G0
weights, 54
Molecules, 53, et seq.
Molybdate, ammonium, 316
Molybdates, S16
Molybdenum, 316, 682
‘sulphide, 316
Molvbdic anhydride, 316
‘oxide, 316
Monamines, 509
Monarda punctata, 470
Monobasiv acids, 66, 251, 448
Monobrom-acetanilide, 408
Monobromated-camphor, 472
Monobromobenzene, 407
Monochlorobenzene, 407
Monochloromethane, 396
Mononchlorotolgene, 409
INDEX.
Monoformin, 426
Monohydroxy) derivatives of hy-
drocarbons, 417
Mononitrocellalin, 495
Monopersul phate, silver, 206
Monopersulphurie acid, 296
Monosulphide, carbon, 302
Monoxide, carbon, 302, see also Car-
bonic oxide
Monoxynuapthalenes, 411
Moonseed, Canadian, 530
Morbid urine, 575
| Mordants, 148
Morphina, 514
Morphine acetas, 514
hydrochloridum, 513
sulphas, 514
Morphine, or morphia, 515, 541
acetate, 282, 514
anuly tical reactions of, 514
distinction from brneine, 525
hydrochloride, 513
in organic mixtures, detection
of, biG
meconute, 515
sulphate, 513, 514
tartrate, 514
Morrhuine, 443
Mortar 338
Mosaic gold, 196,
Moschus, 547
moschiferus, 547
Moss, Carrageen, 494
Ceylon, 494
Chinese, 494
Iceland, 323, 491
Irish, 494
Mottled soap, 441
Moulded silver nitrate, 235
Mountain-blue, 553
limestone, 123
Mucic acid, 446, 486
Mucilage of bael, 495
gum acacia, 121
linseed, 494
marshmallow, 494
squill, 495
starch, 458
tragacanth, 121
Mucilago acacie, 121
tragacanthwe, 121
Mucus in trine, 588
Mudar, 507
Mulberry calculous, 580, 691
esscnee, 405
juice, 552
sugar in, 482
| Mulder’s process for determination
of alcohol, O79
INDEX. 727
Multiple proportions, law of, 51, | Narcotine, 513, 517, 541 -
wet, Se
Murex, 346
Murexid, 346
Muriates, see Chlorides.
Muscarine, 511
Musk, 547
artificial, 547
-deer, 547
Mustard, 427
artificial oil of, 427
black, 427
essential oil of, 427, 470
fixed oil of, 444
Indian, 427
“‘plaster,’”’ 427
white, 427
Mycoder ma aceti, 281, 449
Mydriatics (table), 541
Mylabria cichortt, 473
phalerata, 473
Mvyopsin, 549
Myotics (table), 541
Myrcia acris, 422, 469
oil, 469
Myricetin, 551
Myricyl alcohol, 426
Myristate, glyceryl, 442
Myristic acid, 442, 455
Myristicene, 469
Myristicin, 469
Myristicol, 469
Myristin, 442
Myrobalans, 340
chebulic, 310
Myronate, potassium, 427
Myrosin, 427
Myroxylon Pereirz, 460
tolnifera, 460
Myrrh, 479
Myrrha, 479
Myrrhic acid, 479
Myrtle oil, 470
Myrtus communis, 470
“mystery gold,’’ 197
Mytiloxine, 511
NAPELLINE, 026
Naphthalene, 411, 512
benzoic acid from, 321
series of hydrocarbons, 411
Naphthalenum, 411
Naphthalic acid, 321
a-Naphthol, 335, 411
B -, 411
Naphthols, 411
Naphthyl alcohols, 411
a-Naphthylamine, 335
Narceine, 513, 517, 541
hydrochloride, 517
Nuarthex, see Ferula.
Nascent atoms, 69
chlorine, 69
hydrogen, 69
oxygen, 69
Natal aloes, 413
Nataloin, 413
Natrium, 39
Natron, 39, 272
Nectandra Rodisxi, 529
Nectandrine, 529
sulphate, 529
Needle iron ore, 149
Neem, 507
Negative pole, 67
Neodymium, 171, 682
Neon, 32, 33
Neroli oil, 467
Nessler test, 219, 616
Neuridine, 511
Neurine, 511
Neutral salts, 66
Neutralization, 99
Nickar nuts, 507
Nickel, 143
analytical reactions of, 143
arsenio-sulphide, 143
cyanide, 144
derivation of word, 39
hydroxide, 144
separation of, from cobalt, 142
silver, 143
sulphide, 143
Nickelic hydroxide, 144
Nicotiana tabacum, 536
Nieotine, nicotia, or nicotina, 536
citrate, 536
malate, 536
Nihilum album, 136
Niohium, 682
Nitrate, ammonium, 97, 271, 273
barium, 109
bismuth, 228
cobalt, 142
cupric, 206
ferric, 162
lead, 224
mercuric, 232
mercurous, 232
nickel, 143
pilocarpine, 537
potassium, 78, 271
Silver, 234, 235
ammonium, 237
standard solution of, 624
sodium, 86, 271
strontium, 11!
728
Nitrates, 270
analytical reactions of, 274
quautitative determination of,
G1, ef seq.
Nitre, Jin
chili, 271
cubic, 271
prismatic, 271
sweet spirit of, 304, 401, 403
Nitric acid, 270, 272.
anhydrous, 275
antidotes to, 276
dilute, 272
fuming, 272
in organic mixtures, detec-
tion of, 563
yolumetric determination
of, 62
anhydride, 273, 275
oxide, 274
N itrification, 271
Nitrifying ferment, 271
Nitriles, 447
Nitrite, ammonium, 334
amylis, 334, 405
ethyl, 334, 401
potassium, 334
sodium, 334
Nitrites, 354 |
analytical reactions of, 334
in water, test for, 334
Nitrobenzene, 407, 498
Nitrobenzol, 407
in oil of bitter almonds, test
for, 498
Nitrocellulin, 495
Nitro-compounds, 403
Nitroethane, 403
Nitrogen, 31
derivation of word, 39
free and combined, 33
iodide, 219, 260
in the atmosphere, 31
oxides, 275
peroxide, 270, 274,
preparation of, a1, 167
‘properties of, 32
quantitativ e determination of,
int organic compounds, 673, |
et Beg. |
relative weight of, 32
Nitroglye e rine, 4 38
Nitrohydrocl hlorie acid, a,
Nitromannite, 445
Nitrome aber, 334
Nitro-n: apthalene, 435.
Nitrope ntane, 403, 405
Nitrosn}phonic. ac vid, ant
Nitrosy! chloride, 2 273
Nux-vomieca.
Octahed ron,
INDEX,
| Nitrous acid, 275, 334
determination of, im sul-
phorie acid, 335
auhydride, 274, 275
ether, 334, 401, 403
oxide, 97, 275
| Nomenclature :—
alkaloids, 513
anhydrides, $1
anhydrous salts, 90
-ate, 77, Sl
carbonization, evaporation, ig-
nition, incineration, 107
double salts, 94
ferments and formentation, 421
plocosides, 496
hydrous salts, 90
-i¢c, 77, 81, 151
ide, -ite, SI
iron salts, 151
mercury compounds, 210
notes on, 77, 81, 107, 406, 513
-ol, 437
ous, 81, 141
Nonane, 336
Non-drying oils, 444
Non-metallic elements, 20
Non-metals, 19
Nordhansen sulphuric acid, 205
Norwnal butane, 386
parafiins, 381
potassium chromate, 167
propy! iodide, 383
salts, 66
solutions, 611
a-Normal- -propy|-piperidine, 533
Notation, 54
of organic compounds, 375
Notes, analytical, 246, 350
Nucleins, 543
Nucleo-proteid,
h43
Nucleo-proteids, 546
Nuggets, gold, 197
Numerical and Physical Matters, 40
Nutmeg, expressed oj] of, 442
wil of, 46%
iO?, 523
seeds, 523
iron-containing,
OAK-RARK, M1
Oatmen!, 465
Ooe lusion, 2
Ochre, Bl
bismuth, 227
burnt, 552
c red, 552
Octahed ral sulphur, 285
178
”), 201
INDEX. 729
Octane, '386 Oil, erigeron, 468
(Enanthylate ethy], 405
(Enanthylic acid, 455
Oiticial liquids, specific gravities of,
(00
Oll, ajowan, 466
ajwain, 466
almond, 444
amber, 339
American pennyroyal, 469
anise, 466
apple, 405
arachis, 444
bay, 469
bayberry, 469
benné, 444
bergamot, 466
betula, 466
birch, 458
bitter-almond, 323, 435, 456,
465, 498
artificial, 407, 498
black sassafras, 470
* boiled,’’ 443
boldo, 467
bone, 511
buchu, 467
cacao, 442
cade, 478
cajuput, 467
«ake, 443
camphor, 472
Cannabis indica, 467, 474
caraway, 467
cardamoms, 467
cascarilla, 467
cassia, 467
castor, 444
cedra, 467
chamomile, 466
chaulmoogra, 444
cinnamon, 467
citron, 466
citronella, 468
cloves, 467
cocoa-nut, 442
cod -liver, 443
copaiba, 468
coriander, 468
cotton-seed, 439
cowbane. 468
croton, 444
cubebs, 468
cummin, 468
dill, 466
earth-nut, 444
egy, 543
elder-flowers, 470
elecampane, 468
ethereal, 432
eucalyptus, 415, 468
fennel, 4168
fir wool, 416
garcinia, 443
garlic, 427
“gas, 373
gaultheria, 442
geranium, 468
gingelly, 444
ginger, 468
-grass, 468, 469
grains of paradise, 469
grass, 468, 469, 470
ground-nut, 444
gynocardia, 444
hedeoma, 469
hop, 478
horseradish, 466
Indian hemp, 474
jaborandi, 537
juniper, 469
lard, 442
lavender flowers, 469
foreign, 468
lemon, 466
-grass, 466
lime, 466
linseed, 443
lycopodium, 444
mace, fixed, 442
volatile, 469
male-fern, 444
mangosteen, 443
meadow-sweet, 458, 503
melissa, 471
mint, 469
mustard, artificial, 427
essential, 427, 470
fixed, 444
myrcia, 469
myrtle, 470
neroli, 467
nutineg, fixed, 442
volatile, 469
of vitriol, 292
olibanum, 480
olive, 439, 444
omum, 466
orange-flower, 467
-peel, 466
orris, 469
palm, 442
paraffin, 388
pea-nut, 444
pelargonium, 469
pennyroyal, 469
pepper, 538
730
Oil, peppermint, 469
petit-grain, 467
phellandrium, 415
pilocarpus, 537
pimento, 467
pine wool, 416
ptychotis, 466
pulsatilla, 469
resin, 474
rosemary. 470
roses, 469
rue, 464, 470
sage, 470 .
sandal-wood, 470
sassafras, 470
black, 470
savin, 470
sesame, 444
shark-liver, 444
spearmint, 469
sperm, 426
spike 468
star-anise, 466
strophanthus, 506
sweet-birch, 458, 466
-flag, 470
teal. 444
theobroma, 442
thyme, 470
turmeric, 471
turpentine, 415
rectified, 415
valerian, 471
verbena, 471
water-hemlock, 468
wine, 432
winter-green, 458
wood, 477
worm-seed, 471
Oils, analysis, 681
and fats, composition of, 439
drying, 443
essential, 464, et seq.
tested for alcohol, 465
fixed, 443,
non-drying, 443
terpencless, 465
volatile, 464, et seq.
process for obtaining, 465
Ointment, see Unguentum.
Ointments, 592
Okra, 495
-ol, meaning of, 437
Oleate, glyceryl, 439
lead, 224
mercury, 440
potassium, 439
sodium, 439
veratrine, 440
INDEX.
Oleate, zinc, 440
Oleates, 439, 440
Oleatum atropins, 440
cocaine, 440
hydrargyrt, 440
quinine, 519
veratrins, 440, 540
Olefiant gas, 392
Olefine series of hydrocarbons, 389
Olefines, occurrences of, in nature,
production of, 392
relation to paraflins, 389
Oleic acid, 439, 455, 456
Oleine, 439
Oleoresina, aspidti. 477
capsici, 477
cubebx, 477
lupulint, 478
piperis, 478
zingiberis, 478
Oleoresins, 477
Oleum aethereum, 432
amygdalx expressum, 444
anisi, 466
aurantii corticis, 466
betulz, 466
cadinum, 478
cajuputt, 467
cart, 467
caryophylli, 467
chenopodii, 471
cinnamomi, 468
copaibe, 468
coriandri, 468
cubebx, 468
erigerontia, 468
eucalypti, 468
feniculi, 468
garciner purpuresx, 443
gaultherix, 458
hedeome, 469
juntperi, 469
laranduls, 469
limonis, 466
lini, 443
menthw piperits, 46¢
riridis, 469
morrhusx, 443
myristice, 469
olirse, 439, 444
picis liquide, 478
pimentsx, 467
pini, 416
ricini, 444
roa, 469
roxsmarini, 470
sahinee, 470
suntalt, 470
INDEX, 729
Octane, 356
(Enanthylate ethyl, 405
(Knanthylie acid, 455
Oilieial liquids, specific gravities of,
tM)
Ol, ajowan, 466
Oil, erigeron, 468
ethereal, 442
eucalyptus, 415, 468
fennel, 465
fir wool, 416
garcinia, 443
ajwain, 466 garlic, 427
almond, 444 : 373
aber, S40 gaultheria, 442
American pennyroyal, 469 geranium, 468
anise, 466 gingelly, 444
apple, 405 ginger, 468
arachis, 444 -gruss, 465, 469
bay, 440 grains of paradise, 469
bayberry, 469
benné, 444
bergamot, 466
betula, 466
birch, 458
bitter-almond, 323, 435, 456,
465, 495
artificial, 407, 498
black sassafras, 470
“ boiled,”’ 443
boldo, 467
bone, 511
buchu, 467
cacao, 442
cade, 478
cajuput, 467
wake, 443
camphor, 472
Cannahis indica, 467, 474
caraway, 407
cardamoms, 467
cascarilla, 407
cassia, 467
castor, 444
cedra, 407
chamomile, 466
chan)moogra, 444
cinnamon, 407
citron, 466
citronella, 468
cloves, 467
cocoa-nut, 442
ooml-liver, 449
copaiba, 468
coriander, 468
colton-seed, 430
cowbane, 468
croton, 444
cobels, 464
cummin, 468
dill, 400
ecarth-nut, 444
ege, S44
elder-flowers, 470
clecampane, 468
grass, 468, 4609, 470
ground-nut, 444
gynocardia, 444
hedeoma, 460
hop, 478
horseradish, 466
Indian hemp, 474
jaborandi, 537
juniper, 469
lard, 442
lavender flowers, 460
foreign, 468
lemon, 466
-grass, 466
lime, 466
linseed, 443
lycopodium, 444
mace, fixed, 442
volatile, 469
male-fern, 444
mangosteen, 443
meadow-sweet, 458, 505
melissa, 471
mint, 449
mustard, artificial, 427
essential, 427, 470
fixed, 444
myTein, 460
myrtle, 470
neroli, 47
nutmeg, fixed, 442
volatile, 460
of vitriol, 202
olibanum, 480
olive, 439, 444
omun, 40
orunge-flower, 467
-peel, 466
orris, 469
palm, 442
paraffin, d8e
peanut, 444
pelargonium, 469
pennyroyal, 460
pepper, Ot4
732
Oxide, mercurous, 217
mercury, black, 217
red, 216
yellow, 216
molybdenum, 316
nitric, 274, 275
nitrous, 97, 275
silicon, 338
silver, 236
stannic, 193, 104
stannous, 196
tin, 195, 194, 196
zine, 135
Oxides of nitrogen, 275
identified, 361
Oxidizing agents, 274, 295
flame, 136
Oxyacanthine, 530
Oxyacetate, copper, 206
lead, 220
Oxyacids of sulphur, 296
Oxybromide, bismuth, 229
Oxyearbonate, bismuth, 230
Oxychloride antimony, 187, 191
bismuth, 229, 231
ferric, 156
mercuric, 276
phosphorus, 313
Oxychromate, lead, 226
Oxycopaivie acid, 477
Oxygen, “)
allotropic form of, 261
derivation of word, 39
determination of, in gas mix-
tures, 344
in organic compounds, 783
in the air, 24, 32
its relation to animal and
vegetable life, 24
preparation of, 20, 100
properties of, 23
solubility in water, 24
specific gravity of, 29
Oxygenated water, 108
Oxyglutaric acid, 463
Oxyhydroxides, iron, 149, 157
Oxyiodate, ferric, 280
Oxyiodi ide, bismuth, 229
ce
iron, 14
Oxy malonie . acid, 463
r¢ xy. nitrate, bismuth, | 228
mere uric, 212
Oxy succinic acid, 463
‘Oxy: sulphate, bismuth, , 229
iron, In 2
mere ur ‘it, 21 3
Oxysulphides, antimony, 189
Oxytoluyltropeine, 528°
Ozoke rite, 426
INDEX,
| Ozone, 260
tests for, 261
Ozonic ether, 577
Oxonized air, 261
|
| PALAS tree, 342
Palladium, 201, 683
chloride, 570
Palm-oil, 442
Palmitate, cetyl], 426
glyceryl, 443
molissyl, 426
Palmitic acid, 442, 453
Palmitine, 442
Pan, 343
Pancreatic diastase, 549
enzymes, 549
Pancreatine, 49
Pavcreatinum, 549
Papain, 549
| Papaver rhwas, 552
somntferum, 513
Papaverine, 517, 541
Papaw tree, 549
Paper, bibulous 115
filter, 115
litmus, blue, 99
red, 99
turmeric, #9
Papers, test-, 90
Para-, meanings of, ete,, 306, 410
Para-acetphenetidin, 408
Paracoto, 499
Paracotoin, 499
Paracyanogen, 266, 268
Para-dilhydroxybenzene, 436
Paradol, 469, 531
Paraffin, 388
oil, 382, 388
series of hydrocarbons, 376
wax, 3&7, S88
Paraffinic acid, 388
‘Paraffins, chlorination of, 305
constitution of, 376, ef seq.
formation of, 381
gaseous, 387
general character of, 387
halogen derivatives of, 396
methods of preparation, 342
monohydroxyl derivatives of,”
417
normal, 3&1
occurrence in mature, 381
relations to olefines, 389
solid, 388
synthesis of, 382, ef
hy electrolysis,
—- Parafinum, 385
liquidum, 388
INDEX,
Paraformaldehyde, 448
Paraguay tea, 530
Parahydroxybenzaldehyde, 458
Paraldehyde, 449
Paraldehydum, 449
Paurallin, 504
Para-methyl-isopropy)benzene, 409
Para-phenetol-carbamide, 408
-phenolsulphonic acid, 434
-phenylene-diamine, 511
Paraphthalic acid, 462
Pauratartaric acid, 306
Pareira,, 529
‘aricine, 520
Parietinic acid, 412
Parigenin, 504
Parilla, yellow, 530
Paris blue, 554
red, 552
Particles, elementary, 52
Patent sugar, 485
Pea-nwt oil, 444
Peach, 482
Pear-wine, 422
Pearl-barley, 488
-sago sturch, 490 (fig.).
-white, 220, 555
Pearlash, 71
Peas, 16
Pectin, 494
Pelargonate, ethyl, 405
Pelargonic acid, 455
Pelargonium, 460
oil of, 469
Pelletierine tannaas, 557
Pelletierine, 627
tannate, 537
Pellitory-root, 476
Pelosine, 529
Pencils, “ lead,"’ 208
Penonyroyal, American, oil of, 460
oil of, 469
Pennywort, Indian, 507
Pentane, 386
Pentahydric aleohols, 445
Pentathionic acid, 286, 2i
Pepper, black, 538
cayenne, 531
cubeb, 538
long, 538
melegueta, 469
oil of, 538
oleoresin, 478
resin of, 476
white, 538
Peppermint oi), 469
Pepsinum, 548
Pepsin, 548
in Urine, 681
Pepsinogen, 548
Peptone, 549
Peptones, 46
in urine, 575
Per-, meaning of, 155
Percentage composition, 60
Percha tree, 471
Perchlorate, potassium, 278
Perchloric acid, 279
Perchloride, gold, see Auric chloride.
iron, see Ferric chloride.
anhydrous, see Ferric chlo-
ride, anhydrous,
mercury, see Mercuric chloride,
platinum, see Platinic chloride.
tin, see Stannic chloride,
| Perchloro-methane, 396
Percussion caps, 237
Perfumes, 465
Periodic Law, 364
Perkin’s reaction, 460, 461, 554
Permanent hardness in water, 301
Permanganate, potassium, 81, 139
| Permanganic acid, 141
| Pernitrate, iron, see Ferric nitrate,
| Peroxide, see also dioxide.
barium, 109
chlorine, 279
lead, 224
nitrogen, 270, 274, 275
Perry, 422
Persian berries, 551
Persite, 451
Persodine, 296
Personne’s solution, 627
Persulphate, ammonium, 206
barium, 295
iron, se¢ Ferri¢ sulphate,
mercury, 4ee Mercuric sulphate.
potassium, 205
sodium, 206
Persul phates, 157, 295
«analytical reactions of, 206
Persulphuric acid, 205
anhydride, 205
Peru, balsam of, 323, 460
Peruvine, 460
Petalite, 104
Petit grain oil, 467
| Petrolatwm, 388
alhum, OAS
liquidum, 388
| Pétroléine, 388
Petroleum benzin, 387, 406
purified, 387
crude, 387
other, 387
as, 385
light, 387
734
Pettenkofer’s test for bile, 550
Peumus boldus, 467
Pewter, 156, 193, 222, 225
Pheoretine, 412
Pharaoh's serpents, 345
Pharbitis nil, 502
Pharbitisin, 502
Pharmacognosy, 15
Pharmacology, 18
Pharmacy, 15
Phellandrene, 415, 467
Phellandrivm aquaticoum, 415
Phenacetin, 408
Phenates, 434
Phenazone, 408
Phenic acid, 432
aleohol, 432
Phenocoll, 408
Phenol, 432
liquefactum, 433
-mereury, 434
Phenolphthalein, 411, 462
test solution, 24
Phenols, 452
Phenolsulphonate, sodium, 434
zine, 435 .
Phenolsulphonic acid (ortho), 429
(para), 454
Phenylacetamide, 408
Phenylamine, 407, 511
Phenylearbinol, 435
Phenyl-dimethyl]-isopyrazolone, 408
Phenylglycollic acid, 497
Phenyl group, 409
Phenylhydrazine, 510
Phenylia salicylas,459
Phenylmethyl ketone, 464
Phenyl salicylate, 459
Phosgen, 299
Phosphate, ammonium, 9S
magnesium, 126, 315
separation Of, from
oxalates and ferric
oxide, 359
barium, 317
hydrogen, 110
calcium, 112, 117, 312
acids, 315
hydrogen, 115
codeine, 516
ferric, 161, 316
ferrous, 153
magnesium, in bones, 117
silver, 237, 315 .
sodium, 91, 118
how prepared from calcium
phosphate, 118
Phosphates, 312
analytical reactions of, 315
| Phosphates, quantitative determi-
nation of, Gt'7
Phosphide, hydrogen, 328
trihydrogen, 328, 329
| Phosphines, 509
Phosp
hites, 335
test for, 330
Phosphoantimonic acid, 570
Phosphomolybdic acid, 316, 570
Phosphoric acid, 31, 312, 635
diluted, 31, 319
glacial, 314
quantitative determina-
tion of free, 667
anhydride, 31, 314, 3395
Phosphorized fats, 43
Phosphorous acid, 256, 335, 337
oxide, 335
Phosphorus, 30, 312
acids of, 336
bromide, 256, 314
combustion of, 30
derivation of word, 39
detection of, in orgunic mix-
tures, 565
granulated, 312
molecular formula of, 313
oxychloride, 313
pentachloride, 313
pill, 312
properties of, 30, 312
red or amorphots, 30, 312
trichloride, 282, 313
tri-imlide, 397
Phosphotungstie acid, 570
Phosphuretted hydrogen, 325, 3°09
Photographic hypo-eliminator, 296
“reducer,"’ 206
use of * hypo,” 205
Phthaleins, 411
| Phthalic acid, 322, 411, 462
anhydride, 411, 462
series of acids, 462
| Phyllocyanin, 554
Phylloxanthin, 54
Physical changes, 49
examination of urine, 574
Physostigma, 537
tenenosum, 537
Physostigmine salicylas, 537
wulphas, 537
Physostigmine, 537
Phytolacea, HOT
Phytolacein, 507
Picea excelea, 476
Picoline, 511
Picric acid, 435, 515, 552
Pieverhisa kurroa, 502
Picrorhizetin, 502
Picrorhizin, 502
Picrosclerotine, 476
Picrotin, 503
Picrotoxin, 503, 541
Picrotoxinin, 503
Pig-iron, 150
Pigments, 554
Pigmentum nigrum, 555
Pill, see Pilulae.
Pills, 592
Pilocarpidine, 537
Pilocarpins hydrochloridum, 537
nitras, 537
Pilocarpine, 537
hydrochloride, 537
Pilocarpus, 537
Jaborandi, 537
Pilulse aloes et ferri, 152
ferri carbonatis, 153
todidi, 155
phosphori, 312
Pimaric acid, 442, 474
Pimento oil, 467
Pimpinella anisum, 466
Pine-apple, essence of, 405
wool, 416
vil, 416
Pinene, 415
Pinic acid, 442, 474
Pink saucers, 553
the common, 504
Pins, 193
Pinus, 415, 416, 474
Abtes, 415, 474
australis, 415
laris, 342, 415
Ledebourii, 416
maritima, 415
palustris, 478
picea, 415
pinaster, 415
Pumilio, 416
sylreatris, 416
teda, 415
Pipe-clay, 147
Piper, 538
Betle, 343
Piperazine, 509
Piperic acid, 538
Piperidine, 476, 538
acid tartrate, 538
Piperina, 538
Piperine, 538
Pipette, 258
Pistachia terebinthus, 415
Pitch, 478
Burgundy, 476
Pituri, 537
Piuri, 551
INDEX. 735
Pix liquida, 416, 476
Plant alkaloids, 510
Plants and animals, complementary
action of, on air, 24
Plaster lead, 225
mercurial, 210
of Paris, 112, 555
Plasters, 592
Plastic sulphur, 285
Plate, tin-, 193
Platinic chloride, 200, 570
test solution, 200
sulphide, 200
Platinized asbestos, 291
Platinous chloride, 201
Platinum, 199
analytical reactions of, 210
and ammonium
chloride
and lithium
chloride See
and potassium Chloroplat-
chloride inates,
and sodium
chloride
black, 200
chloride, 200
derivation of word, 39
foil, 199
perchloride, see Platinic chlo-
ride.
residues, to recover, 201
spongy, 201
Pleurisy root, 507
Pluia, 482
Plumbago, 36, 298
Plumbi acetas, 223
emplastrum, 225
iodidum, 224
nitras, 224
oridum, 222
subacetatis, liquor, 223
Plumbic acetate, sulphate, ete, see
Lead.
Plumbum, 38
Pocula emetica, 186
Podophyllotoxin, 476
Podophyllum, 476
peltatum, 476
resin, 476
Poison ivy, 343
oak, 343
Poisonous alkaloids, Stas’s process
for detection of, in or-
ganic material, 568
Sonnenschein’s process, 569
Poisons, antidotes to, see Antidotes.
detection of in organic mix-
tures, 560, et seg.
136
Poisons, of cheese, milk, fish, ctc., | Putassii et sodii tartras, 79, 84, 305
511, 750
Poke root, 507
Polybasic acids, 66, 463
Polychrvite, 503, 551
Polygala senega, 505
Polygalic acid, 505
Polyhydric alcohols, 445
Polymerides, 3&0
Polymerism, 380
Polymers, 380
Polysulphide, calcium, 286
Pomegranate rind, 342
-root bark, 342
Poppy capsules, 513
white, 513
Populus, 503
Porcelain 338
Porridge, 488
Port wine, 422
Porter, 422
Portland cement, 338°
Positive pole, 67
Potash, acetate )
alum,
bicarbonate |
bitartrate
carbouate i
chlorate
citrate Old names
dichromate for potassium
iodate salts, which
nitrate sce.
permanganate
prussiate red j
yellow
sulphate
tartrate
acid
bulbs, 784
caustic, 72
solution of, 72
volumetric determination
of solutions uf, 618
sulphurated, 73
water, 299
Potashes, 71
preparation of, from wood
ashes, 71
Potassit acetas, 75
bicarbonas, 76
bitartras, 71, 84, 305
bromidum, 81
carbonaa, 72
chloras, 277
citrax, 78
effervescens, 78
cyanidum, 266
dtchromas, 167
ferrocyanidum, 266, 326
hydrozidum, 72
hypophosphis, 329
todidum, 80
nitras, 73
permanganas, 82, 139
sulphas, 78, 272
Potassium, 71, 72
acetate, 74 , 283
acid carbonate, 76
oxalate, 303
succinate, 340
sulphate, 272
sulphite, 288
tartrate, 88, 305
alizarate, 411
aluminium sulphate, 146
analytical reactions of, 82
and bismuth iodide, 570
cadmium iodide, 570
diazobenzene hydroxide,
571
platinum chloride see po-
tassium, chloroplatiti-
nate.
sodium, tartrate, 79, 84, 206,
305
angelate, 466
anhydrochromate, 167
antimony! tartrate, 188
benzoate, 460
bicarbonate, 76
bismuth, thiosulphate, 83
bitartrale, 83
borotartrate, 319
bromate, 81
bromide, 81, 257
carbolate, 433
carbonate, 72. 82
volumetric determination
of, 618
Carnot’s test of, 83
chlorate, 20, 277
chloride, 71, 82
chloroplatinate, 82, 83, 201
chromate, 167
cinnamate, 460
citrate, 77
cobaltievanide, 142
cobaltic nitrite, 85, 142
cyanate, 266, 324
cyanide, 266
derivation of word, 39
dichromate, 167
ferricyanide, 326
test solution, 327
ferroevanide, 266, 326
test solution, 326
INDEX, 137
Potassium, ferrous ferrocyanide, | Powder, putty, 195
267 Tripoli, 337
-flame, 84, 106 Powders, 592
formate, 401 specific gravities of, 603
hydrogen carbonate, 76 Praseod ymium, 171, 683
sulphate, 272 Precipitant, 83
tartrate, 83 Precipitate, 82, 83
hydrosulphide, 287 red, 216
hydroxide, 72 white, 218, 255
impurities in commercial, fusible, 218
72 infusible, 219
volumetric determination | Precipitated calcium carbonate, 115
of, 618 sulphur, 285
iodate, 79, 280 calcareous, 286
iodide, 79, 260 Precipitates soluble in solutions of
. Manganate, 81, 139 salts, 246
mercuric iodide, 211, 220 to wash, 115
ineta-bisul phite, 289 to weigh, 640
myronate, 427 Precipitation, 82
nickel cyanide, 144 fractional, 362
nitrate, 78, 271 Precipitatum per se, 216
nitrite, 334 Prepared calamine, 134
occurrence, 71 chalk, 117
oleate, 439 suet, 442
perchlorate, 278 Prepare-liquor, tin, 195
permanganate, 81, 139 Pressure, correction of volume of
volumetric determination gas for, 47, 605
of, 634 -gauges, 45
persul phate, 295 standard, 47
phenol, 132 Prickly ash, 530
preparation of, 71 Primary alcohols, 417
properties of, 72 amines, 503
prussiate red. 326 Principles, 49, et seq.
yellow, 266, 326 Printer’s ink, 555
quantitative determination of, | Prismatic nitre, 271
638 sulphur, 285
red prussiate, 326 Proof spirit, 423
salts, analogy of, to sodium | Propane, 383, 346
salts, 92 Propanctricarboxylic acid, 162
sodium, ammonium, and lith- } Propenyl!, 437
ium, separation of, 105 alcohol, 437
sources, 71 Propeptone, 575
stannate, 195 Prophetin, 500
succinate, 340 Propione, 464
sulphamidobenzoate, 429 Propionic acid, 453
sulphate, 77, 272 Proportions, atomic, 53, 210
sulphides, 73, 287 constant, 51
tartrate, 73, 306 multiple, 51, 275
acid, 78, 83, 305 Propyl alcohol, 424
thiocyanate, 344 Propylamine, 509
yellow prussiate, 266, 326 Propylene, 389, 392
zincate, 137 Propylformie acid, 453
Potato, 538 Propy]l iodide, normal, 383
-oi], 425 iso-, 383
-starch, 487, 490 (fig.). Proteid principles, 542
Powder, see Pulris. Proteids, detection of, in urine, 575
bleaching, 119 Mean composition, 546
compound effervescing, 306 . | Proteolytic enzyme, 549
gray, 210g, Protocatechuic acid, 518
47
738
Protocatechuic aldehyde, 459
Protococcus vulgaris, 445
Protopine, 517, 538
Protoveratridin, 536
Protoveratrine, 536
Proximate analysis, 670
Prune, 484
Pruntum, 484
Prunus serotina, 498
virginiana, 498
Prussian blue, 165, 265, 269, 326, 554
Prussiate of potash, red, 326
yellow, 265, 326
Prussic acid, 265
antidotes, 270
Pseudoaconitine, 526, 527
Pseudohyoscyamine, 536
Pseudoinulin, 491
Pseudojervine, 536
Pseudomorphine, 517
Pseudoxanthine, 510
Pterocarpin, 552
Pterocarpus ertnacens, 342
marsupinum, 342
santalinus, 470, 552
Ptomaines, 511, 570
Ptyalin, 489
Ptychotis ajowan, 466
oil, 466
Puddling, iron, 150
Pulegone, 469
Pulsatilla, 469
oil, 469
Pulvis Algarothi, 187
angelicus, 187
efferrescens compositus, 306
ipecacuanhe et opti, 534
Pumice-stone, 337
Punica granatum, 342, 536
Punicine, 3536
Purified ox-gall, 549
Purple of Cassius, 199, 553
dye, 346
foxzlove, active principle in,
499
Purpurin, 582
Purree, 551
Pus in urine, 587
Pusch's test for tartaric acid in ci-
tric acid, 311
Putreseine, 511
Putty-powder, 195
Pyrethrie acid, 477
Pyrethrin, 476, 5338
Pyrethrum, 176
carneum, ATT
cinerartefolium, AT7
roseum, ATT
Pyridine, 512
INDEX.
Pyridine bases, 512
B-pyridyl-a-lactic acid, 538
Pyrites, copper, 205
iron, 149
Pyroarsenate, sodium, 176
Pyroarsenates, 174
Pyroborate, sodium, 318
Pyrocatechin, 436
Pyrogallic acid, 343, 445, 459
use of, in gas analysis, 344
Pyrogallol, 343, 445, 459
Pyroligneous acid, 281
Pyrolusite, 138
Pyromellitic acid, 463
Pyrometers, 597
Pyromorphite, 318
Pyrophorus, 163
Pyrophosphate, iron, 161, 336
silver, 336
sodium, 336
Pyrophosphates, 336
analytical reactions of, 337
Pyrophosphoric acid, 314, 336
Pyrosulphuric acid, 292, 293
Pyrovanadates. 318
Pyroxylic spirit, 418
Pyroxylin, 495
Pyrorylinum, 495
Pyrrol, 511
Pyrus Cydonia, 495
QUADRIVALENCE, 63
Qualitative analysis, 105, 349, 556
Quantitative analysis, 609, et seq.
Quantivalence, 63
of acid radicals, 63, 251
variation in, 150-151, 327
Quartz, 337
Quassia, 503
Quassin, 503
Quebrachine, 527
Quebracho bark, 527
Quebracho blanco, 527
colorado, 527
Queen’s root, 539
Quercite, 445
Quercitrin, 551
Quercitron, 551
Quercus tinctoria, 551
Quevenne’s iron, 163
Quicklime, 113
Quillaic acid, 505
Quillaja, 505
saponarta, HOO
Quinamine, 523
Quinates, 518
Quince, essence, 405
seeds, 495
Quinia, see Quinine,
INDEX.
Quinic acid, 518
Quinicine, 523
Quinidine, 521
hydriodide, 521
sulphate, 521
tartrate, 521
Quinina, 518
Quinine, bisulphas, 518
hydrobromidum, 519
hydrochloridum, 519
salicylas, 519
sulphas, 518
Quinine, 518, 541
acid hydrochloride, 519
amorphous, 522
and iron citrate, soluble, 160,
519
bisulphate, 519
hydrobromide, 519
hydrochloride, 519
hy pophosphite, 329
iodo-sulphate, 520
kinate, 518
neutral sulphate, 519
oxalate, 519
quinate, 518
reactions of, 519
salicylate, 519
sulphate, 518
Qiuiniretin, 523
Quinoidine, 522
Quinoline, 512
Quinone, 498, 518
RACEMIC acid, 306
Radical, 63
acid, 65
metallic, 65
Radicals, acid, 63, 65, 251
metallic, 65, 71
Radituin, 653
Rai, 427
Raisins, 305, 482
Ranunculus, 469
Raspberry, sugar in, 482
Ratafia, 422
Rattan palm, 475
Ritti, 501
Reaction, acid, 65
alkaline, 64
Reactions, analytical, 70
synthetical, 70
Reagents for alkaloids, 570
list of, xv.
Realgar, 173
Receiver, 131
Rectification, 131
Rectified oil of turpentine, 415
spirit, 131
739
Red, Chinese, 552
chrome, 552
cinchona, 518
coloring matters, 552
corpuscles in blood, 544
earth, 552
enamel colors, 553
gravel, 582
gum, 468
hematite, 149
iodide, mercury, 211
lead, 222, 552
litmus paper, 99
ochre, 552
oxide, iron, 158, 552
mercuric, 216
Paris, 552
phosphorus, 313
-poppy petals, 552
precipitate, 216
prussiate of potash, 327
-Trose petals, 552
sandal- wood, 470, 552
saunders, 470, 552
sulphide, mercuric, 219
Venetian, 158
Reduced indigo, 553
iron, 162
‘** Reducer,” photographic, 296
Reducing flame, 136
Reduction, 69
Reinsch’s test for arsenic, 178
Relative density, see Specific Grav-
ity.
weight of hydrogen and oxy-
gen, 29
Remijia bark, 518
Rennet, 544
extract, 544
Rennin, 544
Reseda luteola, 552
Residues, platinum, 201
Resin, 415, 474
arnica, 474
cannabis, 474
capsicum, 475
castor, 475
copal, 475
ergot, 475
guaiacum, 476, 501
Indian hemp, 474
jalap, 476, 501
kaladana, 502
kamala, 477
kousso, 476
mastic, 476
mezereon, 476
oils, 474
pepper, 476
740
Resin, podophyllum, 476
pyrethrum, 476
rottlera, 477
scammony, 480, 505
soap, 442
Resina, 474
jalapex, 502
podophylli, 476
scammonti, 505
Resins, 464, 473
Resorcinol, 436
Retort, 130
Rhamni succus, 498
Rhamnin, 551
Rhamnose, 500
Rhamnus catharticus, 554
Sranqgula, 5
purshtana, 412
Rhaponticin, 412
Rhatany root, 342
Rheic acid, 412
Rhein, 412
Rheum, 412
Rheumin, 412
Rhodium, 201, 683
Rheeadine, 517
Rhubarb, 302, 412, 476, 551
calcium oxalate from, 303
resins of, 477
root. 412
Rhubarbaric acid, 412
Rhubarbarin, 412
Rhus cotinus, 551
glabra, 343
Rice, 4188
-starch, 189, 490 (fig.)
Ricin, 445
Ricinine, 445
Ricinoleate, glyceryl, 444
Ricinoleine, 444
Ringworm powder, 412
Roceella tinctoria, 445
Roche alum, 147
Rochelle salt, 79, 84, 305, 306
Rock alum, 147
salt, 86, 252
Rohun bark, 507
Roll sulphur, 284
Roman cement, 338
Rosa eanina, 459
gallica, dd2
Rose, 552
-oil, 469
-petals, 552
Rosaniline, 408, 555
Rosemary-oil, 545
Rosin, 415, 474
Rotang palm, 477
Rotten-stone, 146
INDEX.
Rottlera tinctoria, 477
Rottlerin, 477
Rouge, animal, 323, 553
face, 323
mineral, 158, 553
vegetable, 553
Rubia tinctoria, 552
Rubianic acid, 552
Rubidium, 683
Rubijervine, 536
Rubus, 343
Ruby, 146
Rue-oil, 464, 470
Rum, 422
Rumex, 412
Rumicin, 412
Rupi, 526
Rus, 540
Rust, irun, 150
Rutate, glyceryl, 443
Ruthenium, 201, 683
Rutic acid, 442
SABADILLINE, 540
Sabadine, 540
Sabadinine, 540
Sabatrine, 540
Sabinol, 470
Sabinyl, acetate, 470
Saccharated ferrous carbonate, 152
volumetric determina-
tion of, 632
Saccharic acid, 445, 486
Saccharimetry, 678
Saccharin, 428
soluble, 429
Saccharine, 483
Saccharometer, 601, 678
Saccharomyces, 486
cererisiz, 420
Saccharoses, 484
Saccharum, 484
lactis, 486
ustum, 485
Sacred bark, 412
Safety-lamp, 29
Safflower, 553
Saffron, 551
bastard, 553
dver’s, 553
Safrol, 470
Safrolum, 470
Sage, oil of, 470
Sao, 488
palm, 484
starch, 490 (fig.)
Saint Ignatius’s bean, 523
Sal ammoniac, 94
prunella, 272
INDEX.
Sal volatile, 97
Salep, 495
Salicin, 437, 458, 503
Salicinum, 503
Salicy! alcohol, 437
aldehyde, 437, 457
hydride, 458
Salicylate, ammonium, 457
bismuth, 230
Hithium, 104
methyl, 45s
Phenyl, 459
quinine, 519
sodium, 457
strontium, 11]
Salicylic acid, 439, 457
Salicylol, 458
Salicylous acid, 458
Saligenin, 437, 503
Saligenol, 437, 503
Saliretin, 503
Saliva, 345
Salix, 503
Salol, 459
Salseparin, 504
Salt-cake, 49
common, 86, 259
Epsom, 123, 299°
Glauber's, 253
microcosmic, 356
of sorrel, 303
Rochelle, 79, 93, 305, 306
rock, 86, 252
Saltpetre, 272
Chili, 271
Salts, 64, 65
acid, 66, 77, 79
action of blowpipe on, 356
of heat on, 355
of sulphuric acid on, 356
alkyl, 417
animonium, Volatility of, 103
analogies of, 92
analysis of insoluble, 360
anhydrons, 90
hasie, 66
bleaching, 277
constitution of, 65, 251
double, 94, 146
formation of, 75
haloid, 265
hydrous, 90
iron, nomenclature of, 15]
neutral, 66
nomenclature of, Te, 81
normal, 66
Physical properties of, 355
substitution of, for each other,
92
741
Salts, table of the solubility or in-
solubility of, in water, 351 |
Sand, 337
-bath, 35
-stone, 337
-tray, 35
Sandal-wood, oil of, 470
red, 470, 582,
white, 470
yellow, 470
Saunders-wood, red, 470, 552
Sandstone, 337
Sanguinaria, 538
canadensis, 5138
Sanguinarine, 5338
Santalal, 470
Santalin, 552
Santalum album, 470
rubrum, 552
Santonie acid, 504
Santonica, 504
Santonin, 504
Santoninum, 504
Santoniretin, 504
Sap-green, 554
Sapo, 441
kalinus venalis, 44]
mollis, 44]
viridis, 44]
Sapogenin, 504
Saponaria, 505
Saponin, 504
Saponification, 441
Sapotoxin, 505
Sappan, 552
-wood, 552
Sappanin, 552
S:pphire, 146
Saprine, 511
Sareina rentriculi jy urine, 589
Sarcolactic acid, 332, 455
Sarcocephalus esculentus, 475
Sarkine, 511
Sarkosine, 510
Sarracenia purpurea, 540
Sarsaparilla, 5OA
Sarsaparill-saponin, 505
Sarsa-saponin, 505
Sassafras, 470
camphor, 470
(black) oil, 470
oil, 470
Swamp, 507
Sassafrol, 470
Saturated hyd rocarbons, 376
solutions, boiling points of, 595
Saturation, 74
“ Saturn.” the alchemical name for
lead, 223
742
Saturnine colic, 223
Saunders, red, 470, 552
Savin-oil, 470
Saxon blue, 554
Saxony blue, 553
Scale compounds of iron, 159, ef seq.
Scammonin, 505
Scam moniolic acid, 505
Scammoninum, 505
Scammony, resin of, 450, 505
Scandium, 683
Scents, 465
Scheele’s green, 184
Schist, 146
Schenocanlon officinale, 540
Schonbein’s test for hydrocyanic
acid, 270
Schweinfurth green, 184
Science of chemistry, 18
Sella, 505
Scillain, 505
Scillin, 505
Scillipierin, 505
Scillitoxin, 505
Sclerotic acid, 476
Sclerotinie acid, 476
Scoparin, 539
Scoparius, 539
Seqpola alropoides, 535
carniolica, 535
Japonica, 511, 529
Scopolamine, 535
hydrobromide, 535
Scopoleine, 529
Seopoletin, 529
Scott's method fo preparing hydro-
bromic acid, 25
Seutellaria, 507
Scyllite, 484
Sea-salt, 86
-water, 252, 255, 258
-weeds, 248
jelly from, 494
Schacate, ethyl, 405
Secale cereale, 473
Secondary alcohols, A17
amines, 508
Sediments, urinary, gl
bag ir examination
of,
Seed- lac, 5! Ao
Seidlitz. powde r,
Sele nium, 68S.
Semina ardamomi majoris,
Senega, 505
Se negin, 505 ‘
Sewna, Alexandria, 498
India, 49s
Sepia, 555
306
409
INDEX.
Sepiade, 555
'Serpentaria, 527
Texas, 527
Virginia, 527
Serpent's excrement, 583
| Sesumeé-oil, 444
| Sesamum indicum, 444
Sesquiterpenes, 415
Serum praeparatum, 442
| Shale, 146, 382
Shark-liver oil, 444
Shell-fish poison, 511
-lac, 553
Sherry wine, 422
Shot, 222
Shumac, 345
| Siam bengzoin, 459
Side-chains, 381
Sidee, 475
Sienna, 555
yellow, 551
Sifting, an aid to analysis, 555, 362
Silica, 337, 339
| Silicate, aluminium, 104, 146, 337
calcium, 112, 337
lithium, 104
magnesium, 337, 555
and nickel, 143
sodium, 337
BSilicates, S37
quantitative determination of,
HHO
tests for, 339
Silicic acid, 328, 337, 339
anhydride, 337, 338
| Silicide, carbon, 339
Magnesium, S39
Silicinretted hydrogen, 339
Bilicon, chloride, 339
derivation of word, 39
fluoride, 339
hydride, 339
oxide, 338
Bilver, 233
acetate, 284
ammonium nitrate, test solu-
tion, 184, 237
analytical reactions of, 237
anhydrochromate, 238
antidotes, 238
arsenate, 184, 237
arsenite, 184
bromide, 237, 257
chloride, 234, 255
chromate, 169, 238
citrate, 310
coinage, 234
cyanide, 237
derivation of 248
INDEX, 743
Silver, determination of, by cupel- | Soap, marine, 443
lation, 659 Marseilles, 441
dichromate, 169 mottled, 441
extraction of, 233 potassium, 440
fulminating, Berthollet’s, 236 resin, 442
ordinary, 237 sodium, 441
German, 132, 143 soft, 441
iodate, 280 -stone, 555
iodide, 237, 260, 280 -wort, 505
metaphosphate, 333 yellow, 442
monopersul phate, 296 Socaloin, 413
nickel, 143 Socotrine, aloes, 413
nitrate, impure, 234 Soda, sb
mitigated, 236 acetate
moulded, 235 arsenate
pure, 235 benzoate
volumetric solution of, 624 bicarbonate
oxalate, 304 carbonate |
oxide, 236, 237 citro- tartrate
phosphate, 237, 316 hy pophosphite Old names
pure, 235 nitrate , for sodium
pyrophosphate, 336 phenolsulpho- {| salts, which
quantitative determination of, nate see.
658 phosphate,
sodiuin thiosulphate, 295 salicylate
standard solution of nitrate, sulphate
24 sulphite
sulphate, 234 thiosulphate
sulphide, 234, 237, 287 valerate
native, 234 -ash, 90
sulphite, 290 caustic, 86
tartrate, 307 -lime, 371
tree, 238 solution of chlorinated, 91
Sinalbin, 427 washing, 86, 90
Sinapis alba, 427 water, 299
nigra, 427 Sodamide, 510
Sinapin acid sulphate, 427 Sodii acetas, 87
Sinigrin, 427 arsenas, 176
Sinistrin, 505 exsiccatua, 176
Siphon, 116 benzoas, 3:22
Size, 517 bicarbonas, 87
Skulleap, 507 bisulphis, 289
Slag, blast-furnace, 149 horas, 318
Slaked lime, 114 bromidum, 91
Slate, 146 chloras, 92, 279
Smmalt, 141, 553 chloridum, 36
Smelting, copper, 205 citras, 92
Smilacin, 505 hydroridum, 87
Snake-root, black, 507 hypophosphia, 329
Virginia, 527 todidum, O1
Soap, ammonium, 441 nitris, 33-4
-bark, 505 phenolsulphonas, 435
caleium, 441 phoaphas, 1138
Castile, 441 efferrescens, 92
curd, 441 eraiccatur, 92
for Hindoos, 441 pyrophoaphas, 336
Mahommedans, 441 xalicylas, 457
green, 441 sulphas, 253
hard, 441 sulphis, 289
744
Sodit thiosulphas, 294
Sodio-ferrous citrate, 161
hydroxycitrate, 161
Sodium, &6
acetate, 87, 281
test solution, 87
acid carbonate, see Bicarbonate,
sulphate, 253
amalgam, 94
ammonium hydrogen phos-
phate, 356
analytical reactions of, 92
and aluminium, double chlo-
ride, 146
and cobalt nitrite, see Cobalti-
nitrite.
and platinum chloride, see Chlo-
roplatinate.
arsenate, 176
exsiccated, 176
arsenite, 174
benzene- meta-disulphonate, 436
benzoate, 322, 620
biborate, 318
bicarbonate, 87
chemically pure, 614
lozenges, 89
manufacture by the am-
monia process, 89
bisulphite, 289
bromide, 91, 257
cacodylate, 323
carbolate, 457
carbonate, 86, 89
chemically pure, 614
decahyvdrated, 90, 91
manufacture of, 89, 254
monohydrated, 90
volumetric determination,
of, 618
chlorate, 92, 279
chloraurate, 198
chloride, 86
chloroplatinate, 200
citrate, 92
cobaltie nitrite test solution,
oS)
derivation of word, 39
dihydrogen phosphate, 119
ethylate, 423
flame. 92, 106
glycocholate, 550
gold thiosulphate, 295
gravimetric determination, 643
hydrogen carbonate, 87
sulphate, 252, 253
hydrosulphide, 287
hydroxide, 86
standard solution of, 621
INDEX.
Sodium hydroxide, volumetrie de-
termination of, 618
hypochlorite, 91
hy pophosphite, 329
iodide, 91
manganate, 139
meta-bisulphite, 289
metantimonate, 189
metantimonite, 189
metarsenite, 174
meta-thiantimonite, 189
methyl] arsenate, 323
nitrate, 86, 271
crude, 258
nitrite, 334
occurrence, 86
oleate, 439
ortho-thiantimonite, 190
oxalate, 303
perinangauate, 139
peroxide, 23, 92
persul phate, 296
phenol, 457
phenolsulphonate, 434
pheny! carbonate, 457
phosphate, 91, 118
effervescent, 92
how prepared from calcium
phosphate, 118
test solution, 119
potassium, lithium, and am-
monium, separation of,
106, 107
tartrate, 79, 305, 306
preparation of, 86
pyroarsenate, 176
pyroborate, 318
pyrophosphate, 336
quantitative determination of,
644
salicvlaldchyde, 458
salicvlate, 457
salts, analogy of, to potassium
salts, 92
sources of, 86
silicate, 339
silver thiosulphate, 295
stannate, 195
sulphate, 253, 291
sulphide, 287
sulphite, 289
taurocholate, 550
tetraborate, 318
tetrathionate, 295
thiantimonate, 189
thiosu] phate, 294
urate, 346
valerate, 346
zincate, 137
INDEX.
Soft soap, 441
Soils, analysis of, 681
Solanidine, 538
Solanine, 538, 541
Solanum dulcamara, 538
tuberosum, 538
starch of, 490 ( fig.)
Solazzi juice, 500
Solder, 193, 222, 228
Solid caustic potash, 72
fats, 442
Solids, to take the specific gravity
of, 601, et seq.
lighter than water, to take the
specific gravity of, 604
soluble in water, to take the
specific gravity of, 603
Solubility of carbonic anhydride in
water, 298
of gases in water, 23
or insolubility of salts in water,
table of, 351
Soluble cream of tartar, 319
ferments, 421
glass, 339
saccharin, 429
starch, 492
Solution of ammonia, 95
almmonium acetate, 95
Citrate, 98
sulphide, 100
arsenic, acid, 174
alkaline, 174
calcium chloride, 112
sulphate, 122
caustic potash, 72
chlorine compound, 254
De Valangin’s, 174
Donovan's, 173
ferric chloride, 156
nitrate, 162
sulphate, 157, 159
ferrous sulphate, 151
Fowler's, 174
formaldehyde, 448
fractional, 90, 362
hydrogen sulphide, 101
iodine, 259
lead subacetate, 223
lime, 114
litmus, 99, 620
magnesium ammonium
phate, 667
citrate, 126
nitroglycerin, 438
normal chromate, 167
phosphorie acid, 313
potash, 72
potassium permanganate, 139
745
Solution of sodium arsenate, 176
of solids, 357-361
theory of, 363
zine chloride, 134
Sonnenschein's process for poison-
ous alkaloids, 569
Soot, 36, 297
Suphora tomentosa, 534
Sophorine, 5:
Sorbinouse, 483
Sorbite, 445
Sorrel, salt of, 303
wood-, 303
Soymida febrifuga, 507
Soymidg cortex, 507
Sozoiodol, 429
Sozolic acid, 429
Spanish licorice, 500
Spar, fluor, 112, 327
heavy, 109, 290
Sparteine, 539
Sparteinz sulphas, 539
Spathic iron-ore, 149
Spearmint-oil, 469
Specific gravities, 47
Specific gravity, 599, et sec
bottles, 599
of gases, 48, 604
of liquids, 47, 599
of ofticial liquids, 600
of oxygen, 29
of powders, 603
of solids, 47, 601, et seq.
lighter than water, 604
of soluble substances, 603
heat, relation to atomic weight,
Spectroscope, 250, 559
Spectrum, 559
analysis, 250, 559
Specular iron-ore, 149
Speculum metal, 193
Speiss, 143
Spermaceti, 426
Spermatozoa in urine, 589
Sperm-oil, 426
Sphacelinic acid, 476
Spinelle, 146
Spirea ulmarta, 458, 503
Spirit, methylated, 415
of camphor, 473
of French wine, 422
of myrcia, 422
of nitrous ether, 401
of turpentine, 415
petroleum, 406
proof, 423
pyroxylic, 418
rectified, 131
746
Spirit, wood-, 415
Spinita, 422, 502
Sparitua etheria, 432
compositus, 42
nifrom, SH, 402
ammonites,
aromatious, U7
volumetric determin- |
ation of, 617 )
amygdale amare, 405
anim, 465
comphare, 473
innamomi, 465
JSrumenti, 422
gaultherue, 465
glycerylia nitratia, 435
juniperi, 45
lacandule, 465
menthe piperite, 465
riridia, 465
nilri duleia, 405
rina gallici, 42:
Spodumene, 103
Spogel seeds, 495
Sponge, 258, 46
Spongine, 46
Spongy platinum, 201
Spontaneous ignition, 163
Spotted eranesbill, 343
Spruce fir, 476
Bpurge laurel, 476
Squalus carcharias, 444
Bquill, 495
-bulb, 505
vinegar of, 282
Standard pressure, 47
Standard solution of inline, 628
potassium dichromate, 631
Portman ganate, G45
silver nitrate, G24
sodium hydroxide, 621
thiosulphate, 635
sulphuric acid, 614
‘temperature, 47
Stannate, sodinm, 195
Stannates, 194
Stannic me ‘id, 104,
anhydride,
chloride, 1
e oxide, 193, 1M
sulphide, 196 ¥ c
< ual anhydrous, 196
‘Stannous ¢ hloride, 194
“wolid, 194
test solution, IM
hydroxide, 196°
oxi lo, 196
sulphide,
Stannam, 20
|
|
|
|
196
re
195
INDEX.
Stephimgria, 534
Star-anise oil, 466
Starch, 457, 565
actiou of diastase upen, 490, 492
of dilote acids upon, 463
animal, 491
barley, 488
blue, 457
bromide, 258
eellolose, 489
eran — composition of, 457,
jodide, 80, 200, 458
maize, 487
mucilage Oy. 455
potato, 457
quantitative determination of,
67T7
rice, 488
soluble, 493
wheat, 455
white, 404
Starches, microscopy of, 459
| Stas’s process for poisonous alka-
loids, 568
State of concentration, 251
*~“Stavesacre, 534
seeds, S44
Steapsin, 549
Stearic acid, 437, 439, 453
Stearine, 439
Stearoptens, 464
Steatite, 555
Steatolytic enzyme, 549
Steel, 150
wine, 161
Stereochemical theory, 481
Stibines, 500
Stihinm, 37, 156
Stibnite, 156
| Stick lac, 553
licorice, 5
Still, 130
Stillingia, 539
— syleeticn, 539
Stillingine, 539
Stone-coal, 193
red, 652
wire, 348
| Storax, 393, 461, 474
Stout, 422
Stramonium, Aa
Strasburg turpentine, 415
Strawberry, sugar in, 482
Stream-tin, 193
| Strength " of acids, 251
Strontianite, 111
Stroutii bromidum, 111
iodidum, 111
INDEX.
Strontii salicylas, 111
Strontium, 111
analytical reactions of, 111
carbonate, 111
chromate, 112
derivation of word, 39
flame, 112
hydroxide, 111
nitrate, 111
salicylate, 111
sulphate, 111
sulphide, 111
Strophanthidin, 506
Strophanthin, 506
Strophanthinnmm, 506
Strophanthus, HAM
ivombé, 506
Structure of flame, 28
of molecules, 374, et seq.
of organic compounds, 374
Structural formulm, 375
Strychnina, 524
Strychnine nitras, 524
sulphasx, 524
strychnine or strychnia, 523, 541
analytical reactions of, 524
citrate, 524
hydrochloride, 524
in organic mixtures, detection
of, 565
nitrate, 524
physiological test, 525
sulphate, 524
Strychnos ignatius, 525
htt promica, nO, 525
Styracin, 460
Styrax, 461, 474
Styrol, 460
Styrone, 460
Subacetate, copper, see Oxyacetate,
lead, 223
Snubcarbonate, iron, 155
bismuth, 230
Subchloride, mercury, «ee Mercu-
rons chloride.
Suberate, ethyl, 405
Sublimate,
corrosive, 213
Sublimation, 96, 214
Sublimed sulphur, 26
Subnitrate, bismuth, 228
Substances readily oxidized, quanti-
tative determination of, 25
reduced, quantitative determi-
nation of, 634
Substitution, 179, 395, 410
products, 305
Succinate, ammonium, 332
barium, 340
Succinate, ferric, 340
potassium hydrogen, 340
Succinates, 239
Succinic acid, 339, 461
Suceinum, 339
Succus limonis, 310
Sucrate, iron, 152
Sucrose, 420, 454
Suet, 442
prepared, 442
Suffioni, 318
Sugar, auction of alkali upon, 485
amount in various fruits, 482
barley, 485
beet root, 481, 484
brown, 484
burnt, 455
candy, 454
-cane, 482, 484
cube, 454
detection of, in urine, 576
from cauoutchouc, 484
encalyptus, 486
fish, 454
larch, 486
milk, 483
mountain ash, 483
muscles, 483
starch, 483
Turkish manna, 486
fruit, 482
erape-, 482
inverted, 482
lichen, 445
loaf, 484
lump, 484
-maple, 454
milk-, 456
moist, 484
of gelatin, 550
of lead, 223
patent, 483
quantitative determination of,
7th
test for, 482
and, 486
syrup, 454
Buint, 440
Sulphamido-benzoutes, 429
Sulphanilic acid, 305
Bulphate, acid potassium, 272, 201
sodium, 253
aluminiom, 147
ammoniun, {4
ferrous, 152
ferric, 147
bariom, LOA, 200, 205
beberine, 520
bismuth, 228
748
Sulphate, calcium, 112, 122, 290
chromic, 166, 168
cinchonidine, 521
cobalt, 142
codeine, 516
copper, 206
anhydrous, 206
cupric, 206
ammonium, 207
ethy] hydrogen, 392
ferrous, 151
solution of, 152
hydrogen, 293
indigo, 276
iron (ferric) and ammonium,
147
iron (ferrous) and ammonium,
152
lead, 226
Magnesiuin, 123, 290
manganese, 138, 254
mercuric, 212, 213
mercurous, 212, 213
morphine, 514
nickel, 143
potassium, 78, 272
hydrogen, 272
quinine, 519
silver, 234
sodium, 254, 291
hydrogen, 252
strontium, 111
strychnine, 523
zinc, 133
Sulphates, 290, et seq.
analytical reactions of, 293
quantitative determination of,
664
Sulphations, 363
Sulphide,-allyl propyl, 427
antimony, 186, 189, 190
arsenic, 173, 183
native, 173
barium, 109
bismuth, 227, 230
cadmium, 232, 233
calcium, 120
cobalt, 142
copper, 206
and iron, 205
cupric, 206, 287
hydrogen, 100, 164, 287
iron, 37, 154, 164, 165
lead, 222, 225
native, 222
manganese, 140
mercury, 219
native, 209
wolybdenum, 316
INDEX.
Sulphide, nickel, 143
platinum, 200
potassium, 73, 287
silver, 233, 237, 287
native, 233
sodium, 287
stronium, 111
tin, 195, 196
zinc, 131, 136
native, 131
Sulphides, 284
analytical reactions of, 287
detection of, in presence of sul-
phites and sulphates, 290
quantitative determination of,
663
Sulphite, barium, 291
calcium, 290
silver, 290
sodium, 289
zinc, 136
Sulphites, 288
acid, of organic radicals, 428
analytical reactions of, 289
detectiou of, in presence of sul-
phides and sulphates, 290
quantitative determination of,
664
Sulphocarbolates, 434
Sulphocarbolic acid, 434
Sulphocarbonates, 302
Sulphocarbonic anhydride, 302
Sulphocyanates, see Thiocyanates.
Sulphocyanides, see Thiocyanates.
Sulphonal, 428
Sulphonic acids, 428
Sulphonethy]methane, 428
Sulphonethylmethanum, 428
Sulphonmethane, 428
Sulphonmethanum, 428
Sulphostannates, see Thiostanuates.
Sulphovinic acid, 203, 392
Sulphur, 36. 284
adulteration of, 286
alcohols, 428
allotropic forms of, 285
amorphous, 285
arsenic sulphide in, 183, 285
black, 285
bromide, 287
calcareous precipitated, 288
chloride, 286
derivation of word, 39
determination of, 663
ethers, 432
flowers of, 284
hy pochloride, 227
iodide, 259, 287
liver of, 73
INDEX.
Sulphur, milk of, 285
molecular formula of, 285
octahedral, 285
oxyacids, 296
plastic, 285
precipitated, 285
prismatic, 285
roll, 284
sublimed, 284 .
washed, 285
Sulphur lotum, 285
precipitatum, 285
sublimatum, 284
vitum nigrum, 285
Sulphurated antimony, 189
lime, 120
potash, 73
Sulphurets, see Sulphides.
Sulphuretted hydrogen, see Hydro-
gen sulphide.
Sulphuric acid, 290, et. seq.
antidotes to, 294
aromatic, 293
determination of, in vine-
gar, 664
diluted, 293
fuming, 293
impurities in, 292
manufacture of, 291
nitrous acid in, 334
Nordhausen, 293
organie mixtures, detec-
tion of, in, 563
purification of, 292
standard solution of, 614
volumetric determination
of, 623
anhydride, 292, 293
Sulphuris todidum, 259, 287
Sulphurous acid, 283
volumetric determination
of, 628
anhydride, 36, 213, 288
Sulphydrate ammonium, solution
of, sce Ammonium hydrosul-
phide.
Sulphydric acid, 264
Sumac or sumach, 343
Sumatra benzoin, 321
camphor, 472
Sumbul, 478
radir, 478
root, 478
Suimbulic acid, 478
Sumbuolic acid, 478
Snperphosphate, 315
Supporters of combustion, 28
Suppositories, 592
Surface, unit of, 41
749
Surgery, 18
Swamp sassafras, 507
Sweet birch, oil of, 458, 466
flag, vil, 470
spirit of nitre, 4083
Sweetbread, 549
Swertia chirayita, 335
Sylvestrene, 415
Sylvic acid, 441, 474
Symbol, function of a, 58
Symbol, atomic, 69
of elements, 59, 682
illustration of chemica] action
by means of, 59, et. seq.
Symmetrical compounds, 410
Sympathetic inks, 143
Synaptase, 497
Synthesis, 50
. Syrup, golden, 485
! Syrups, 592
specific gravities of, 601
Syrupua, 434
actdi citrict, 309
hydriodici, 260
aurantit forum, 467
calcti lactophosphatis, 331
caleis, 114
ferri todidt, 37, 155
hypophosphitum, 329
compositus, 330
tolutanns, 460
TABLEs, various, see Appendix.
' Tacks, tin, 193
Tale, 146, 555
Taleum, 555
Tallow, 442
Tamarindus, 308
: Tampico jalap, 502
Tannate. antimony, 342
ferric, 165, 341
gelatin, 341
Tannic acid, or tannin, 340, 459
test solution, 341
Tanning, 341
Tantaluin, 683
Tapioca, 438
starch, 483, 490 (fig.)
Tar, 116, 475
Taraxacin, 507
Tararacum, 507
Tartar, cream of, 71, 84, 305
emetic, 188
determination of antimony
in, 630, 652
meaning of, 305
soluble cream of, 319
Tartarated antimony, 188
Tartaric acid, 305
750
Tartaric acid test solution, 306
volumetric determination
of, G24
series of moids, 462
Tartarus boraralus, 319
Tartrantimonious acid, 188
Tartrate, acid ammonium, 102
potassium, 75, 83, 305
autimonyand potassium,160,188
calcium, 305, 307
ferrous, 161
iron, 161
and ammonium, 161, 308
potassium, 159, 161, 308
morphine, 514
potassium, 78, 305
wid, 78, 83, 305
and sodium, 79, 305, 306
antimonyl, 138
silver, 307
Tartrates, 305
analytical reactions of, 307
volumetric determination of,
Ld A
Tartronic acid, 463
Taurine, 510, 550
Tauirocholates, 550
Taxine, 530
Tea, 539
'Tea-oil, 444
Telini fly, 473
Tellurium, 683
Temperature, absolute, 46
correction of volume of gas for,
46, 605
aoe of, 43,
standard,
Temporary “he So in water, 301
Terebenthene, “415
Terebene, 416.
Terehbennm, 416
Terebinthina, 415
canadensis, 415, 478
Terephthalic acid, 462
Terminalia chebula, 340)
Terpe ne series of hydrocarbons, 415
Te srpenoless: oils, 4 465
Te Tper nes, 415
Te rpin hydrate, ¥ 416
Te rpine ne, 415 5.
Terpine vol, 467
Terpini hydras, 416
50S
AIS
‘Terra di sic nom,
Japonica, ' 342 Me “7
ret Mice
Te rpinoler ne,
Te rtiary, alcohols, 417
amines, 50S
amy! ale ohol,
INDEX,
2 eahhe of, BS
Tetano-cannabin, 475
Tetanine, 511
Tetrabasic acids, 463
Tetraborate, sodium, 318
Tetrachloride, carbou, 306
Tetrachloromethane, 396
Tetra-iodo-pyrrol, 511
Tetrahydric alcohols, 445
Tetramethylthionine hydrochlo-
ride, 556
Tetrathionate, sodiam, 205
Tetrathionie acid, 206
Tetrethyl-ammonium jodide, 508
Tetronal, 428
Texas serpentaria, 527
Tfol, 338
Thalleioquin, 519
Thalline, 523
Thallium, 683
Thebaine, 517, 41
| Theine, see Caffeine.
Thenard'’s-blue, 553
Theobrama-cacao, 442, 539
-oil, 442
Theobromine, 539
relation of to caffeine, 539
Theophylline, 539
Theory of solution, 363
Therapeutics, definition and deriva-
tion of, 18
Thermometers, 43, 593
Centigrade, 44
Fahrenheit, 44
Thermometric scales, conversion of
degrees of, 44
Thiantimonate, sodinm, 189
Thio-alcohols, 428
Thio-antimony compounds, 189, 1p0
Thio-arsenic compounds, 183
Thiocarbonates, 302
Thioearbonic anhydride, 302
Thiocyanate, awmoniim, 269
ferric, 165, 269, 344
mercuric, 345
potassium, 344
Thiocyanates, 44
distinetion of, from
und meconstes, 332, 344, 345
Thioevanic acid, 344
| Thiocyanogen, $45
-Thio-ethers, 452
-Thionic acids, 207
-Thiostannates, 196
Thiostt}phate, calcinm, 26q
289, 294
sudiunm,
INDEX.
Thiosulphate, sodium gold, 295
preparation of, 204
silver, 205
standard solution of, 635
Thiosulphates, 204
tests for, 205
Thiosulphuric acid, 294
Thio-tin compounds, 196
Thorium, 683
Thorn-apple, 535
Thoroughwort, 507
Thrombosin, 544
Thujone, 470
Thusmaseulum, 479
Thyme, 470
oil of, 470
Thymene, 470
Thymol, 460, 470
iodide, 471
Thymolis todidum, 471
Thymus vulgaris, 470
Tiglic acid, 444
Tiles, 338
Tin, 193, 683
amalgam, 193
unalytical reactions of, 195
and antimony, separation of,
17
antidotes to, 197
arsenic and antimony, analyti-
cal separation, of, 202, ef seq.
block, 193
chlorides, 194
(derivation of word, 39
dropped, or grain, 103
foil, 193
granulated, 193
oxides, 194
perchloride, see Stannie chlo-
ride.
plate, 193
powdered, 193
prepare-liquor, 195
‘stone, 199
tacks, 103
-white cobalt, 141
Tineal, 318
Tinetura cantharidia, 473
ferri chloridi, 156
hydrastis, 5A0
bod, G50
Physvatignatia, 537
strophanthi, 50M
Tincture of phenol-pthaloin, 624
Tinctures, 582
Tinospora cordifolia, 507
Tinospore radix et caules, DOT
Titanium, 683
Tobaceo, 536
Toddalia, 07
aenleata, SAT
Toddaliw radia, HOT
Tolene, 460
Tolu, balsam, 323, 460
syrup, 4(W)
Toluene, 406, 408
-sulphonic acid, 428, 420
nmide, 420,
chloride, 429
Toluidine, 408
Toluol, 408
| Toly! alcohol, 435
Tonka bean, 461
Tourmalines, 337
Toxicodendric acid, 343
Toxicology, 559
Tragacanth, 121, 404
Tragacantha, 121
Traganthin, 494
Treacle, 285
Tree, lead, 227
silver, 238
Tri-acid bases, 66
Triamines, 509
Triangle, wire, 103
Triatomic alcohols, 437
Tribasic acids, 66, 251, 462
Tribromomethane, 400
Tribromophenol, 434
Tricarballylic acid, 462
Trichloracetal, 450
Trichloracetic acid, 451
Trichloraldehyde, 449
Trichlorbutylidene glycol, 453
Trichlorethylidene ethy! ether, 452
glycol, 450
Trichlorobenzeue, 410
Trichloromethane, 306
Trichloromethylbenzene, 222
Trichloro-tertiary-buty! aleohol,
424
Trichlorotoluene, 322, 400
Triethylamine, 506
Triethy!l-ammonia, 508
ammonium-iodicde, 508
Trigovella fonum-greewm, 540
Trigonelline, 540
Trihydric alcohols, 437
Tribydroxybenzene, 445
Trihydroxy-benzoic acid, 459
Trihydroxy!l derivatives of hydro-
carbons, 437
Tri-iodomethane, 401
Trimethy] bongene, 406
methane, S80
Trimethylamine, 508
Trimethyilxanthine, 539
Trinitrine, 438
752
Trinitrocellulin, 495
Trinitro-phenol, 435
tertiary-butyl-toluene, 547
Trional, 428
Trioses, 481
Triphaue, 103
Triple phosphate, 584
Tripoli powder, 337
Trithionic acid, 296
Triticum, 507
repens, 507
starch, fig. of, 490
Trivalence, 63
Trivalent radicals, 63
Trochisci acidt tannict, 341
potassti chloratis, 278
sodii bicarbonatis, 89
Tropate, tropine, 528
Tropeines, 528
Tropic acid, 528
Tropidine, 528
Tropine, 528
esters, 528
Trypsin, 549
Tubes for collecting gases, 21, 22,
23
funnel, 25
glass, see Glass tubes.
Tungsten, 683
Tunicin, 496
Turbad, 502
Turbid, 502
Turmeric, 471, 551
oil, 471
paper, 99
Tumerol, 471
Turnbull's blue, 164, 327, 554
Turnsole, 554
Turpentine, 415
American, 415
Bordeaux, 415
Canadian, 415
Chian, 415
crude, 415
French, 415
rectified oil of, 415
Russian, 416
spirit of, 415
Strasburg. 415
Venice, 415
Turpentines, 478
Turpeth mineral, 213
veretable, 213, 502
Turpethin, 502
Terpethum, 502
Turps, 415
Tylophora asthmatica, 535
Tvlophorine, 535
Type-metal, 156, 222, 22
INDEX.
Tyrosine, 510, 583
Tyrotoxicon, 511, 571
ULEXINE, 534
Ultimate analysis, 670
Ultramarine blue, 554
green, 554
Ultraquinine, 523
Umbelliferone, 479
Umber, 555
Unguentum acidi tannici, 341
belladonnex, 529
hydrargyri, 210, 440
ammoniati, 218
dilutum, 210
nitratis, 212
oxidi flavi, 216
rubri, 216
todi, 259
paraffini, 388
veratrine, 540
zinct oxtdi, 135
Units of length, surface, capacity,
and mass, 40, 41
Univalence, 63
Univalent radicals, 63
Unsaturated compounds, 389
Unsymmetrical compounds, 410
Uranium, 683
Urari, 525
Urate, lithium, 104
Urates, 345
Urceola elastica, 471
Urea, 324, 455, 510, 573
artificial, 324, 573
determination of, in urine, 578
et seq.
nitrate, 574
test for excess of, in urine, 578
tests for, 573
Ureometer, Doremus, 579
Urethane, 455
Uric acid, 345, 539, 577, 581, 584,
589-591
rough determination of, in
urine, 578
Urinary calculi, 572
examination of, 589
sediments, 581
microscopical examination
of, 583
Urine, 345, 572
average composition of solids,
572, 573
color of, S581
diabetic, 577
determination of sugar in, 678.
of urea in, 578
morbid, examination of, 575
Ms
INDEX,
Urine, proteids in, 575
Urinometer, 577, 601
Urobilin, 574
Urochrome, 574
Uroerythrin, 574, 582
Urostealith, 589
Ure ursi, 342
Valency, 62
variation in, 150, 151, 327
Valerate, amyl, 347, 405
eupric, 343
ferric, 347
sodium, 346
zinc, 136, 347
Valerates, 346
Valerian oil, 471
Valeriana, 471
officinalis, 471
fallichii, 471
Valeric, or valerianic acid, 346, 425,
453
Valerone, 464
Valonia, 341
Vanadates, 318
Vanadinite, 318
Vanadium, 317, 683
relationship to nitrogen, phos-
phorus, and arsenic, 317
Vanilla, 459
planifoltia, 459
Vanillin, 459
Vanillinum, 459
Vapor-density, 48, 605
determination,
method, 606
Gay Lussac’s method,
606
Meyer's method, 606
Variolaria, 554
Vasaka, 510
Vaseline, 388
Vasicine, 540
Vegetable albumin, 516
alkaloids, 510
and animal life, relation of oxy-
gen to, 24
casein, 516
crocus, 55]
fibrin, 545
gelatin, 494
green, 554
jelly, 494
oil, 439
rouge, 593
Vegeto-animal alkaloids, 511
Venetian red, 158
Venice turpentine, 415
48
Duwas’
753
‘Venus, ” the alchemical name for
copper, 205
Veratralbine, 536
Veratridine, 540
Veratrina, 540
Veratrine, or Veratria, 536, 540, 541
oleate of, 440
Veratroidine, 536
Veratrum, 526
album, 536
officinale, 540
ciride, 536
Verbena oil, 471
Verdigris, 206
Verjuice, 305
Vermillion, 219, 552
Vermouth, 422
Veronica virginica, 507
Viburnin, 507
Viburnum opulus, 507
prunifoltum, 507
Vinegar, 281
brewed, 282
brown, 281
determination of mineral acids
in, 564
malt, 2382
of opium, 282
of squill, 282
red-wine, 281
white, 231
white-wine, 281
wood, 281
Vinum antimonii, 189
ferri, 161
amarum, 161
specacuanhie, 535
Violet, 458
Virginia snakeroot, 527
Vitellins, 543
Vitriol, blue, 152. 206
green, 152, 202
oil of, 292
white, 133
Volatile oils, 464
concentrated, 165
Volatility. of ammonium salts, 108
Volatilization, 103
Voleanic ammonia, 94
Volume, combination by, 60
of gas, corrections of, 47, 604,
605
Volumetric determination of :—
acetic acid, 622
ammonia, solutions of, 615
ammonium bromide, 626
carbonate, 617
antimony, 630
arsenic, 6:29)
7o4
Volumetric determination of :—
borax, 617
chlorine, solution of, 635
citric acid, 623
ferric salts, 637
ferrous carbonate,
3:2
iodide, 627
sulphate, 632
hydrochloric acid, 623
hydrocyanie acid, 625
iodine, 636
iron iodide, 627
magnetic oxidc, 633
saccharated carbonate, 632
sulphate, 632
lactic acid, 623
lead acetate, 657
sub-acetate, solution of, 657
lime, chlorinated, 636
solution of, 636
syrup of, 617
water, 617
nitric acid, 623
oxalic acid, 634
oxalates, 634
potassium bicarbonate, 618
bromide, 626
carbonate, 618
citrate, 619
cyanide, 626
hydroxide, 618
iodide, 627
tartrate, 619
Rochelle salt, 620
saccharated ferrous carbonate, 632
soda, chlorinated, solution — of,
636
sodiuin, 618
arsenate, 629
benzoate, 620
bicarbonate, 618
carbonate, 618
citrate, 619
hydroxide, 618
iodide, 627
tartrate, 619
thiosulphate, 632
spirilas dumoniwv aromatious, O17
sll phuric acid, 625, 628
sutphiiraus acid, 622
tartarte seid, 625
Volumetric quantitative analysis,
oll
solutions, GEA 621, 624, 628,651,
0555, OD
Vouacapoua araroba, AL?
Vuleanite, 171
Vuleanized India-rubber, 471
saccharated,
INDEX.
Wanoo bark, 507
Wakhima, 527
Warmth of animals, how kept up, 24
Wash-bottle, 116
hot-water, 116
Washing precipitates, 116
--0d 8, 56, 90
Water, 26, 27, 129, see Aqua.
acrated, 299
amwonia, 94
in potable, 616
baryta, 109
-bath, 115, 118
bitter almond, 268
boiling-point of, 594, 505
chalybeate, 149
chlorine, 34, 254
chloroform, 400
composition of, 27
creosote, 434
cubic inches of, in a gallon, 606
determination of, 669
distilled, 131
formation of, 27
-glass, 338
Gioulard, 224
hardness of, 301
-hemlock, oil of, 468
lead in, 225
lime, 114
maximum density point of, 47
nitrates in, 334
of crystallization, 90
quantitative determination
of, 669
-oven,. 640
oxygenated, 109
potash, 269
purification of, 129, 130
soda, 299
weight of a cubie inch of, 606
Wax, bees, 426,
Carnauha, 426, 453
paraflin, 387, 388
Waxes, 426
Wedgwood-ware, 338
Weighing-tubes, 639
Weight, 50
molecular, 53, e€ seq.
of sar, G05
of hydrogen, 606
of water, 606
Weights, 505
and measures, 40, ef seq.
and measures of the metric sys-
tem, 10, 12 °
atomie, 52, 45
molecular, 51
Weld, 552
Welding, 150
Wheaten flour, 488
Wheat-starch, 488, 490 (fig.).
Whey, 486, 544
Whisky, 422
White acid, $28
arsenic, 173, 174
Castile soap, 441
hellebore, 536
American, 536
indigo, 553
lead, 223, 555, 657
marble, 112
mustard, 427
pepper, 538
petrolatum, 388
Pigments, 555
poppy, 513
precipitate, 218, 255
fusible, 218
infusible, 218
resin, 474
vitriol, 133
wax, 426
Whiting, 117, 555
Whortleberry, sugar in, 482
Wild black cherry, 498
Indigo, 529
Willow bark, 503
Wine, 422
antimonial, 189
apple, 422
heavy oil of, 432
ipecacuanha, 534
iron, 161
bitter, 161
oil of, 432
orange, 422
pear, 422
quinine, 519
sherry, 422
steel, 161
Vinegar, 281
Wines, 422, 592
Winter-green, oil of, 458
Wire-gauze, 35
triangle, 103
Witch-hazel, 507
Witherite, 109
Wood, charcoal, 202
creosote, 434
-naphtha, 419
sorrel, 30-2
specific gravity of, 604
-O11, 477
-spirit, 418
-tar, 416, 478
Vinegar, 281
Woody night-shade, 538
INDEX.
Wool! fat, 440
hydrous, 440
Woorara, 525
Wormsceed, 471
American 471
oil, 471
Wormwood, 340, 498
Wourali, 525
Writing-ink, 341
Wrought iron, 150
XANTHINE, 53
calculus, 589, 591
Xanthocreatinine, 510
Xanthorrhiza apiifolia, 530
Xanthoxylon fraxineum, 530
Xenon, 32, 33
Xylene, 406
Xylenes, 436
Xyloidin, 488
Xylonite, 496
YEAastT, 420
Yelk of egg, 543
Yellow, chrome, 226, 551
cinchona bark, 519
coloring matters, 551
dock, 412
jasmine, 535
mercuric jodide, 21]
oxide, 216
ochre, 551
parilla, 530
755
prussiate of potash, 266, 326
sienna, d51
soup, 442
wax, 426
wood, 551
Yolk of egg, 543
Ytterbium, 683
Yttrium, 683
ZAFFRE, lil
Zea Mays, 487
Zine, 1:3!
acetate, 135
analytical reactions of, 136
antidotes to, 137
arsenate, 185
bromide, 134
carbonate, 131, 134, 137
chloride, 133
derivation of word, 39
detection of, in presence of man-
ganese, nickel, and cobalt,
145
ferrocvanide, 137
granulated, 25
hydroxide, 137
756 INDEX.
Zinc, hydrox ycarbonate,134,135,137 | Zincate, sodium, 137
in organic mixtures, detection | Zinci acetas, 135
of, 561
iodide, 134
methide, 385
molecular formula of, 132
oleate, 440
oxide, 134
phenolsulphonate, 136, 435
quantitative determination of,
648
stearate, 136
sulphate, 132
sulphide, 136
native, 131
sulphite, 136
valerate, 136, 347
white, 134, 555
Zincate, potassium, 137
carbonas precipitatus, 134
chlorudi liquor. 134
chloridum, 133
oxidt unguentum, 135
ortdum, 135
phenolsulphonas, 136, 435
stearas, 136
sulphas, 132
valeras, 136, 347
Zincum, 132
Zingiber, 471
Zirconium, 683
Zyinase, 420
Zymolysis, 421
Zy mosis, 421
Zymotic alkaloids, 511
\
'CS5l Attfrield, J. Yerl4
Ac& Chemistry.
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DATE DUE