This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project
to make the world's books discoverable online.
It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject
to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books
are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.
Marks, notations and other maiginalia present in the original volume will appear in this file - a reminder of this book's long journey from the
publisher to a library and finally to you.
Usage guidelines
Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing tliis resource, we liave taken steps to prevent abuse by commercial parties, including placing technical restrictions on automated querying. We also ask that you:
+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for personal, non-commercial purposes.
+ Refrain fivm automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the use of public domain materials for these purposes and may be able to help.
+ Maintain attributionTht GoogXt "watermark" you see on each file is essential for in forming people about this project and helping them find additional materials through Google Book Search. Please do not remove it.
+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner anywhere in the world. Copyright infringement liabili^ can be quite severe.
About Google Book Search
Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web
at|http: //books .google .com/I
id, Google
id, Google
CHEMISTRY:
GENERAL, MEDICAL, AND PHARMACEUTICAL,
THE CHEMISTET OF THE n. S. PHAHMACOPffilA. A MANUAL
ON THE GENERAL PEIKCIPtE3 OE THE SCIENCE, AND THEIR APPLICATIONS TO MEDICINE AND PHARMACY.
BY JOim ATTFIELD, Ph.D., E.O.S.,
B BECOML AMD ENLAEGED ENGLISH EDITIOH. REVISED BY THE AUTHOR.
PHILADELPHIA:
HBNEY 0. LEA. 1871.
Hoa,d, Google
But Ibe sreaMst error of sll U, mislBking the uUimate end ot knowledge ; for
e for victory and contention ; many (or lucre and s llTslihood ; and bol few for iloylng the Dlyioe gift of reason lo tlie ces nnd beneflt of mankind. Thus some ear to seek in knovlEdge a coucb. for a searclilng spirit; otlieis, e. walk for a idering ralpd ; others, a tower of stale ; others, a fori, or comniuiaing ground;
Hosled^y Google
PREFACE.
This manual is intended as a systematic exponent of the general truths of Chemistry. It is written solely for the pupils, assistants, and principals engaged in medicine and pharmacy. The volume will be found equally useful as a reading-book for gentlemen having no opportunities of attending lectures or performing experiments, and as a handbook for college pupils; while its comprehensive Index, containing five thousand references, will fit the work for consultation in the course of business or profes- sional practice.
From other text-booka it differs in throe particulars: first, in the exclusion of matter relating to compounds which at present are only of interest to the scientific chemist ; secondly, in containing the chemistry of every substance recognized offlcially, 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 anthor's opinion, best meets the requirements of medical and phar- maceutical students in Great Britain and America. Intro- ductory pages are devoted to a few leading properties of the elements. A review of the facts thus unfolded affords opportunity for stating the views of philosophers respect- ing the manner in which these elements influence each other. The consideration in detail of the relations of the elementary and compound radicals follows; synthetical and analytical bearings being pointed out, and attention
id .y Google
frequently directed to connecting or underlying truths or general principles. The chemistry of substances natu- rally associated in vegetables and animals is next consi- dered. Practical toxicology and the chemical as well as microscopical characters of morbid urine, urinary sedi- ments, and calculi are then given. The conclnding sec- tions form a laboratory-guide to the chemical and physical study of quantitative analysis. The appendix includes a long table of tests for impurities in medicinal preparations ; also a short one of the saturating powers of acids and alkalies, designed for use in prescribing and dispensing.
In the course of the treatment outlined in the preceding paragraph, it will be observed that the whole of the ele- ments are first noticed superficially, and that the chemistry of the common metallic radicals precedes that of the rarer ; while the sections on the acidulous radicals are similarly divided. The basjlous radicals will be found to be arranged according to analytical 'relations, the common acidulous according to satuvating-power or quant ivalence, and the rarer acidulous radicals alphabetically. It will be appa- rent, also, that in certain cases the same classes of facts and principles arc brought three or four times under con- sideration, the points of view, however, differing according as interest is concentrated on physical, synthetical, analy- tical, or quantitative properties. This arrangement of matter was adopted partly from the belief that tbe separate and general truths of chemistry never enter the mind in the order of any scientific classification at present possible. In the current state of chemical Iinowledge consistency in the methodical arrangement even of elements can only be carried out in one direction, and is necessarily accompa- nied by inconsistencies in other directions, a result most perplexing to learners, and hence totally subversive of tbe chief advantage of elassifl cation. For this reason the writer has preferred to lead up to, rather tl:ian follow, sci- entific classification^ — -has allowed analogies and affinities to suggest, ratlier than be suggested by, classification.
id .y Google
AmcFBg the acidulous radicals, especially, any known sys- tem of classiflcatiori would have giveti 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 insufficient to enable them to gain a thorough knowledge of the science. One great advantage of the mode of treatment is that difficulties of nomencla- ture, notation, chemical constitution, and even those arising from conventionality of language, are explained as they arise, instead of being massed under the head of " Introduc- tory Chapters," " Preliminary Considerations," or " Gene- ral Remarks," which are commonly too difficult to be understood by a beginner, and too voluminous to be remem- bered except by the aid of subsequent lessons.
The chemical notation of the work is tn accordance with modern theories. Equations illustrative of pharmacoptsial processes have a name attached to each formula.
Chemical nomenclature has been modernized to the extent of defining the alkali-metal and earthy salts as those of potassium, sodium, ammonium, barinm, calcinm, magnesium, and aluminium, instead of potash, soda, am- monia, baryta, lime, magnesia, and alumina. The author confidently believes that this change, now adopted by all prominent writers on chemistry, will be accepted and he- come popular with pharmacists, as it is a step in the direc- tion of simplicity and consistency, and involves far less hypothesis than is contained in the old system. The name nitrate of potash, for example, was based on the pure assumption that nitre contained oxide of potassium or potash and nitric anhydride, then erroneously termed acid. By the modern name, nitrate of potassium, all that is intended to be conveyed is that nitre contains the ele- ment common to all potassium compounds, and the group of elements common to all nitrates. "Under the old method, students always experienced difficulty in distinguishing 1*
id .y Google
Tl PBEFAOE.
saltsof the metal from salts of its oxide — salts of potassium, fov instance, from salts of potash ; under the new view no such difflcalty arises. Names a«ch as potassium nitrate or potassic nitrate are also consistent with modern views, but for general adoption are too unlike the original. The contractions in Latin for names like "nitrate of potas- sium" are identical with those names resembling " nitrate of potash;" an accidental circumstance that will much facilitate the general introduction of the former among medical practitioners aud pharmacists, and a practical advantage that must determine the choice over the other chemically equivalent names just mentioned. It is not too much to expect that these slight modifications of the old names will be adopted in the next editions of the Pharma- copceias of the United States and Great Britain, and those works thus be made to reflect the present state of chemical science.
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 impe- rial measures are employed.
It is hoped that the numerous etymological references scattered throughout the following pages will be found useful. Words in Sreek have been rendered in English characters, letter for letter.
Students are strongly recommended to test their pro- gress by frequent examination. To this end appropriate questions are appended to each subject.
In response to a call from professional friends in the tinited States, I have carefully revised tho work for the American student, introducing the Cherai9tr3^ of the Prepa- rations and Materia Medica of the United States Pharma- copceia, and making such other additions and corrections as seemed necessary to present the science in its latest development.
LoNDO.v, Dei^embBr, 18T0.
id .y Google
APPARATUS
APPARATUS,
L tof apparatus suitable for a short course of practical chemistry
n 1 d n the preparatioa of elemeutary gases aniljtical reactions
Df omm o metais and acidulous radicals analyBis of single salt'!
1 m al tox oology, and the examination of unne urmaij sediments,
I al b —
fed aeu fast-tuhee.
1 t-tube tand.
Testtube cleaning-brash.
A few pieces of glaas tubing, 8 to 16 in. long, with a few inches of India-riujber tubing to fit.
Small flask.
Two small beakers.
Two small funnels.
Two wateh-
Twooi
■r three g Wash-bottle. Small pestle an A 2-pint basin.
{This set cart be obtained of any chemiccd-apparaius majcet about seuew dollars.)
A2-inchanda?-inLhPvap basin
Two porcelain cruubles
Blowpipe.
Oruciblc-tougs.
Eouud file.
Triangular file.
Small retort-stand.
Sand-tray.
Wire triangles.
Platinum wire and foil.
Filter-paper, Two dozen corks.
A set of evaporating-basins, of the following sizes ; —
One Scinch, One 4^inch,
One 7|-inch. Two 3-inch,
One 6i inch. One retort-stand and three rings. Two teat-glasses. One halt-pint fi^k. One half-quire filtflr-paper. Two porcelain crucibles. One measure-glass, 5 oz. Blowpipe, 8-inch, Black's. Two glaas funnels. One dozen test-tubes (German
glass). One test-tube brush.
One pair of 8-inoh brass crucible- Two soup-platos.
One flat plate.
Two spatula knives.
One pair of scissors.
One round file.
One triangular file.
One half-pound of glass rods.
One half-pound of glass tubing.
One foot of small India-rubber tnbing.
Three doz. corks of various sizes.
Platinum wire and foil.
Test-papers.
A nest of three beakers, ( TItis set can be obtained of any chemical-appaTatiM maker for ahoiU twelve dollars.) A sponge, towels, and note-book may be included.
id .y Google
The following apparatus should be ready to the hand of students following' au extended course of practical chemistry in a room set apart for the purpose ; — ■
A bench or table and atoo!.
Water-supply and waste-pipe.
A cupboard attached to a chiin- ney with a« outward draught
A furnace fed with coke; tongs, hot-p!ate or sand-bath, &c.
A waste hos.
Shelves for chemicala and other materials in jars or hottles.
Gas-supply and lamp with flexi- ble tube.
Other articles, such as flasks, retorfa, receivers, condensers, large evaporating-dishes, may be obtained as wanted. In Quantitative Analysis the apparatus described in the sections on that subject will be required.
Test-tnbe lack two do^en holes
Iron stand oi cyliudei for tup- porting large diihc^
Iron adaptors for fltt ng dinhes to cyluider
Pestle and mortii 5 or 6 mthea
One 6-inch fuauel.
Brown pan, 1 or 2-gallon.
White jug, l-gallon.
Water-bottle, qnart.
Twenty-eight test-bottles, 6-oz.
REAGENTS.
Certain chemicals are used so frequently in analytical processes that it is desirable to have small quantities placed in bottles in front of the operator. As these reagents or "teats" are generally employed in a state of solution, nearly all the solid salts may at once be dis- solved in distilled water. The bottles should not be more than about three-quarters full ; single drops, if required, can then be poured out with ease and precision. The following liat is Sulphuric Acid, strong. Nitric Acid, strong. Hydrochloric Acid, strong. Acetic Acid, strong.
I Sol,ofPota3h,5perctorU.a.P.
" Soda, 5 to 15 per cent.
" Animon.l0p.ct.ortJ.8.P. I Lime Water, saturated.
The next nine may contain about 10 per cent of Si
Carbonate of Ammonium (p. 67). Chloride of Ammonium. Oxalate of Ammonium. Phosphate (p. 68) or Arseniate (p. 130) of Ammonium.
Sulphjdrate of Anim.on. (p. 68). Chloride of Barium. Chloride of Oaleinm (p. 78). Phosphate of sodium. Neutral Ohromate (p. 76).
The succeeding six may have a strength of 5 per cent. : — Perrooyanide of Potaasinm. I Perchloride of iron (p. 110).
Perridcyanide of Potassium. Nitrate of Silver.
Iodide of Potassium. ] Perchloride ofFlatinum (p. 201).
Tartaric Acid, in powder. Copper, in borings or turnings.
id .y Google
CONTENTS.
Pee¥ace iii
Apparatus "vii
Reagents "viii
Intkodtjction 13
Genkeal Peoperties of the Non-Metallic Ele- ments 15
Symbols and Derivation op Names op Elements . 21
The General Peinoiples of Chemical Philosophy . 32 Common Metallic Elements, their Official Pre-
PAEATIONS, AND TeSTS: —
Salts of Potassium, Sodium, Ammonium, Baeium, Calcium, Magnesium, Zinc, Aluminium, Iron, Arsenicum, Antimony, Copper, Mercuet, Lead,
SiLVEE 43
Analitiqai. Charts, for Ordinary Metals . . , lt9 Karer Metallic Elements, tiieie Ofpigial Prepara- tions, AND Tests : — Salts oe Lithium, Strontium, Man&anese, Cobalt, Nickel, Cheomium, Tin, Gold, Platinum, Cad- mium, Bismuth 182
Analytical Charts, por all Metals 211
Common Acidulous Radicals, Official Acids, and Tests l^
id .y Google
Chlobibrs, Bhomides, Iodides, Cyanides, Nitrates, CHLORATEe, Acetates, Sulphides, Sulphites, Sulphates, Cakbonates, Oxalates, TAftXftATES, Citrates, Phosphates, Borates ...... 211
Salts of BiARER Acidulous Radicals : —
Benzoates, Cyanates, Formates, Hippurates, Fer-
ROOYANIDBS, FbRRIDCTANIDES, FLUORIDES, HyPO-
phosphites, Lactates, Malates, Me con at es, Met APHOSP HATES, Nitrites, Phosphites, Pyro-
SlLIOATES, StILPHOCYANATES, TaN-
[, Urates, Valerianates . ■ . 216 Analytical Chart for Acidulous Uadioals . . . 303
SrsTEMATic Analysis 305
Alkaloids, Amylaceous and Saccharine Substan- ces, G-LucosiDEs, Alcohol and Allied Bodies, Albumenoh) and Gelatisenous Substances, Peps IN E, Fatty Bodies, Resinoid Substances,
Coloring-matters 315
Toxicology 386
Examination oe Morbid TJbine and Calculi . ■ . 39i
Official G-alenioal Preparations 40T
Official Chemical Preparations . i09
Quantitative Analysis: —
Introductory Remarks 409
Measurement of Temperature 412
Estimation of Weight 417
Weights and Measures 411
Specific Gravity 424
Correction op the Volume of G-ases for Pres- sure AND Temperature 430
Volumetric Analysis 436
Gravimetric Analysis 457
Dialysis 494
id .y Google
CONTENTS, si
Appendix: —
Table ot' Official Tests for Imptjrities in Pre-
PARATIOKS OF THE BRITISH pHAKMACOPffirA . . 497
Saturation Tables 505
Table of Strength op Alcohouto Liquiss , . 606 The Elements, their Symbols and Atomio
Weishts 507
Index 509
id .y Google
id, Google
CHEMISTRY:
GENERAL, MEDICAL, AND niARMACEUTICAL.
INTRODUCTION.*
The numerous solid, liquid, and gaseous substances of whieU onr earth and atmosphere, and, apparently, the snn, moon, and other celestial bodies are composed, may be resolved into sixtj-three distinct forms of matter, appro- priately termed Elements. Of these elements only a few fsuch as gold) occur naturally in the juicombined state, the greater number being disguised by a kind of union so close as to conceal them from ordinary methods of observation. Thus none of the common properties of water indicate that it is composed of two elements, both gases, but diifering much from each other: nor can the senses of sight, touch, and taste, or other common means of examination, detect in their concealment the three elements of which sugar is composed. The art by which these and all other compound substances are resolved into their elements, is termed Chemistry, derived possibly from the Arabic word kamai, to conceal, whence al kiniia, or alchemy, an art which at the time the name alchemy was given had but little more for its object than the transmutation of the baser metals into gold. The art of chemistry also includes the construc- tion of compounds from elements, and the conversion of substances of one character into those of another. The general principles or leading truths relating to the elements, to the manner in which they severally combine, and to the properties of the compound substances formed by their union, constitute the science of chemistry.f
*■ After reading the first three pages, the laboratory-student may commenoe praotioal work by preparing oxygen.
t Persona who praetiae the art and soienoe of Chemistry are known as Chemists, thotigh ooiiTentioDally the latter namo inolndea those
id, Google
14 HON-METALLIC ELEMENTS.
I'rom these few words concerning the nature of the art and science of chemistry, it will he seen that in most of the occupations that engage the attention of man it plajs an important part — in few more so than in the practice of Therapeutics* and Pharmacy .f
Air, water, food, drugs, and chemicals, in short all ma- terial suhstances, are composed of a few elements. An intimate knowledge of the properties of these, and of the various substances they form by combining with each other, a fenowledge of the power or force (the chemical force or chemical affinity) by which the elements contained in those compounds are held together, and an application of such knowledge to Pharmacy and Medicine, must be the objects sought to be attained by the learner, for whom this work has been especially written.
The Elements. — Of the sixty-three oiements only thirty- nine are of medical or pharmaceutical interest; of thuse, about two-thirds are metals, and one-third non-metals: the remainder are so seldom met with in natnro as to have received no practical appl cat on e the m medicine, art, or
who simjly deal in oiemio 1
appellatioiis of Analytital Pba d
mists. The ooioponndet of me ne % oy ommon conaeni a cliemist only beeaaae he 9 coiia an j engaged n operations with chemical substances Dsed as remed al gents b moral right to the name depending on the amount of chemical knowledge he possesses concerning those sabatancea. If he keeps an open shop, he is in Great Britain known aa a Ckemisi and Druggiat, hia higher title being Phm- macettiical Chemist; these respectire designations he legally assumes on passing the minor and major Esami nations, conducted by the Pharmacentlcal Society of Great Britain in accordance with the pro- visions of the Pharmacy Acts of 1852 and 18i)3. These classes are frequently spoken of collectively as Pharmacists, a term also used in the United States.
* Therapeutics (Sifa'mirTiite; thernpentikos, from flspaflriuB, tJierapeuo, to nnrse, serve, or cure) is that branch of medicine which treats of the application of remedies fordiseases : it inclndes dietetics. The thera- peutist also takes cognizance of hygiene, that department of medicine which respects the preservation of health.
f Pharmacy (from tjiiffixKai, phariaakon, S, drug) !s the generic name for the operations of preparing or compounding medicines, irhether performed by the Medical Practitioner or by the Chemist and Druggist. It is also sometimes applied, like the corresponding tenn in Surgery, to the apartment in whicli the operations are conducted.
id, Google
OXYOEN. 15
manufacture. Before intimately stadyiog the elements,* it is desirable to have some general notions concerning them : such a procedure will also servo to introduce the practical student to his apparatus, and make him better acquainted with the various methods of manipulation .f
Metallic Elements. — With regard to the metallic elements, it may be safely assumed that the reader haa sufficient know- ledge for present purposes ; but little, therefore, need now be said respecting them. He has an idea of the appearance, relative weight, hardness, &c,, of such metals as gold, silver, copper, lead, tin, zinc, and iron. If he has not a similar knowledge of mercury, antimony, arsenic, platinum, nickel, aluminium, magnesium, potassium, and sodium, he should commence liis studies by seeing and handling specimens of each of these metals.
N<m-metallia Elements.X — 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 out of their number.
OXYGEN.
Prefwation. — Ab oxygen is tiie most abundant element in nature, forming, though in a combined state, about one-half of the whole weight of our globe, it may safety be assumed that this element can readily be obtamed in the Iree condition in a staje of purity. In fact, the air itself contains about one-fifth of its bnlk of oxygen, though that element cannot be separated aafficiently easily and readily for experimental purposes. It is preferable to apply heat — that force wlueh will often be noticed as antagonistic, so to speak, to chemical uuion, heat generally separating particles of matter further from
* Possibly eome of these bo3iea may, beraaftsr, be provetl to ba compouwds ; at present they cannot be reeolTed into simpler forma of iDatter, hence muet be oonstderect to be elemertts.
t This allusion to apparatus need not diaoourage the youngest pupil. With the aid of a few phials, wlne-glassea, or other similar vesaels always at hand, ha may, by studying the following pages, learn the chemioal reactions whioh are constantly oeonrring in the course of making np medicines, understand the processes by whioh medicinal preparations are manufactured, and deteot adulterations, imparities, or faults of manufacture. Among the anhstaiioes ased in medicine, will be found nearly all the chemicals required. If, in; addition, a dozen teat-tubes, and a tew feet of glass tubing be procured, moat of the experiments described may be performed. For lists of apparatus and chemicals see AppendiK.
} These bodies are sometimes termed metaUnids (from /ihii^J.ii, tnetallon, a metal, and iTtoc, eidns, likeness) ; bnt the name is not appro- priale, for the non-metalUe elements have no likeness to metala.
id .y Google
16 NON-METALLIC ELEMBNTB.
each other, while chemical attraction tends to bind them closer together: it is betf«r to heat certain compounds containing oxygen ; the latter is then evolved in its normal, natural condition of gas. Several substMices, when heated, yield oxygen; bat, for convenience and economy, the crystalline body known as chlorate of potassium is best fitted for the experiment. The size and form of the vessel in which to heat it will mainly depend on the quantity required; but for the purposes of the Btndent the best i.B a test-tube, an inBtrument in constant requisition in studying practical chemistry. It is simply a thin tube of glass, a few inches m 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.
Process.— -Heat chlorate of potassium {say, ae much as ■will lie on a shilling) in a test-tuhe, by means of a spirit- or gas-flame; gaseous oxygen is quickly evolved. Befove applying heat, however, provision should be made for col- lecting the gas.
CoUecHon of Gases.— Procure a piece of glass tubing about the thickness of a quill pen, and a foot or eighteen inches long, and fit it accurately to the test-tube by means of a cork. (Longer tubes may be neatly cut to any size by smartly drawing the edge of a tiiangular file across the glass at the required point, then clasping the tube, the scratch being between the bands, and pulling the portions asunder, force being exerted in a slightly curved direction so as 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, a rat-tail file, or, best of all, by one of a set of cork-borers^ — pieces of brass tubing sharpened at one end and having a flat head at the other. Setting aside the test-tube for a few minutes, proceed to bend the long piece of tubing to the most con- venient shape for collecting the gas.
To bend Glass Tubes. — Hold the pai-t of the tube re- quired to be bent in any gas- or spirit-flame (a fish-tail gas- let answers very well), constantly rotating it, so that about an inch of the glass becomes heated. It will soon be felt to soften, and will now, yielding to the gentle pressure of the Angers, assume 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 about 90 degrees.
Sowce of Heai. — -The source of heat for the test-tube may be the flame of an ordinary spirit-lamp, or, still better where coal-gas is procurable, a mixture of the latter with air. The simple flame of a
id, Google
OXYGEN. It
n argand gas-burner ia preferred by some operators, especially when tie nsual gas chimney is replaced by a metal one about four or five inches long. If a piei,e or cap of wiie gauze Be fixed on to the top of the metal chimney then the unbt gas which issnes from the jets of the argand bnrner become mixed with air inside the chimney, and the mixture whea lit on the outer side of the gauze, burns with a flame as smokeless and as little colored as that of a spirit-lamp. Gas-lamps espec ally contti i cted to barn a mixture of coal-gas and air are sold by chemical apparatus manafaoturers.
Collection, eto (continued) — Fit the eprk and bent tnbe into the test-tube the apparatua will then be ready for delivei'iug gas at a cum enient distance from the heated portion of the arrangement. To collect it, have ready three or four test-tubes filled with water, and inverted in a basin, or other similar vessel, also containing water, taking care to keep the mouths of the tubes a little below the surface. Now apply heat to 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 issues may bubble into and gradually fill the inverted test-tubes. The first tubeful may be rejected, as it probably consists of little more than the air originally in the apparatus, and which has been displaced by the oxygen. That which comes afterwards will be pure oxygen.
On the large ioale, oxygen may be made in the same way, larger vessels (glass flasks or iron bottles) being employed. Less heat also will be necessary if the chlorate of potassium be previously mixed with very fine sand, or, still better, with about a fourth of its weight of common black oxide of mauganese.
Note on the Collection and Storage of Gases. — It may be as well to state liat nearly all gases, whether for experimental or practical purposes, are collected and stored in a similar manner. Even coal- gas is generated at gas-works in iron retorts very much the shape of tfist-tabes, only they arc as many feet long as a test-tube is inches; and the well-known gigantic gas-holders may be viewed as inverted iron test-tubes of great diameter.
Froperties, — One characteristic of this non-metallic ele- ment is invisibility. Again, it obvionsly is not very solu- ble in water, or it could not be collected by the aid of that liquid.
Oxygen is soluble fa a certain extent, however (about 3 volumes in 100, at common temperatures), or fishes could not breathe.
Other noticeable features are its want of taste and smell. Next, to show the relation of oxygen to combustion, re-
id.y Google
18 NON -METALLIC ErjEMBJJTS.
move one of the tubes from the water by placing the thumb over its mouth, apply for a second a lighted wood match to the orifice ; the gas will be found to be incom- bustible. Extinguish tbe fiame of the match, and then quickly introduce the still incandescent carbonaceous ex- tremity of the wood halfway down the test tube ; the wood will at once burst into flame, owing to the extreme vio- lence with which oxygen supports combustion. These tests of the presence of oxygen may also be applied at the extremity of the delivery-tube whilst the gas is being evolved. (It ia desirable to retain two tubes of the gas for nse in subsequent experiments.)
Relation of Oxygen, to AtHmal and Vegetable Life. — Not only the carbon at the end of a piece of charred wood, bat any oYIier aub- stanoe that will bnrn in aiv fwhich, as will be seen preeently, is diluted oxygen) will bnrn more brilliantly in pnre oxygen. The warmfh of the body of animals is kept np by tne contmuous burning of the carbonaceous matter of the blood in the osy^en of the air drawn into the lungs. The product of this combustion is a gaseous com- pound of carbon and osyren termed carbonic acid gas, a gaa which, in sunlight, is decomposed in the cells of plants with fixation of the carbon and liberation of the osjgen; hence the atmosphere is 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 componnds, or in the separation of any of the following non-metallic elements from their combinations. It is to the properties of the elements themselves that he should restrict his attention. Working thus from simple to more complex fiicts, he will in due time find that the com- prehension of such actions as occur in the preparation of these few elements will be easier than if he attempted their full stndy now.
HYDEOGEN*
Freparation and Collection.— Tlie element of hydrogen is also a gas, and is obtainable from its commonest com- pound, water (one-ninth of which is hydrogen), by the agency of hot zinc or iron, or by the action of either of those metals on cold diluted sulphuric acid. The appa-
* Within the past year Graham Las ohtft!ned alloys of hydrogen with palladium and othiir metals, oomponnds in whiuh several hun- dred times its bulk of gas is rataintid by the metal in vaauo or even at a red heat. This is physical confirmation of the opinion long held by ehemisls, that hydrogen is a metal.. Graham already terms it hydrogenium, aud considers its relatii-o weight In tUa solid state to benearlythree-fourths that of water.
id .y Google
HYDROGEN. 19
ratiis used for making oxygen may he employed for this experiment ; but no lamp is required. Place several pieces of thin zinc* in the generating-tube, and cover them with water. The Dollecting-tubes being ready, add strong sul- phuric acid (oil of vitriol) to the zinc and water, in the proportion of about 1 volume of acid to 5 of water, and fit on the delivery-tube ; the hydrogen is at once evolved. Having rejected the flrat portions, collect four or five tubes of the gas in the manner described under Oxygen.
In inakiug larger quantities, bottles may be used instead of test- tubes.
Other metals, notably potassium and sodium, liberate hydrogen the moment they come into uontact with water; but the processes are not economical.
Properties. — Like oxygen, hydrogen is invisible, inodor- ous, and tasteless. If made with iron it has a strong smell, but this is due to impurities contained in the metal. Apply a flame to the mouth of the delivery tube ; ignition of the hydrogen ensues, showing that, unlike oxygen, it is combustible. Immerse a lighted match into a tube con- taining hydrogen ; the gas is ignited, but the match be- comes extinguished. This shows that hydrogen is not a supporter of combustion. Hydrogen in burning unites with the oxygen of the air and forms water, which may be condensed on a cool glass or other surface. Prove this by holding a glass vessel a few inches above a hydrogen- flame. Id burning the hydrogen contained in one of the tubes, the flame is best seen when the tube is held mouth upwards, and water poured in so as to force out the gas gradually. If, instead of this gradual combination of the two elements oxygen and hydrogen, they be mixed to- gether in the right proportions and then ignited, esplosion results. Prepare a mixture of this kind by filling up with liydrogen a test-tube from which one-third of the water has been expelled by oxygen. Remove the tube from the water, placing a finger over the mouth, and, having a lighted match ready, apply the flame ; a slight explosion
• The beat form ie granulated zinc (_Zincam Granulalii!a,B. P.) made bj heating scraps of common sheet z[ug iu a ladle orer a Bre, and as soon as melted pouring, iu a slow stream, iiito a pail of water from a height of 8 or 10 feet. Eaoh drop of zinc thus yields a thin little bell, which, for ifs weight, presents a lafge surface to the action ot the aoid water. If the zino Is allowed to hscome hotter than necessary, the little hells will not he formed.
id, Google
20. NON-METALLIC ELEMENTS.
will result, owing to the instantaneous combination of the two elements, and tlie expansive force of the steam produced.
These two gases thus unite at a temperature considerably above that of boiling-waf«r, two Tolumea of hydrogen and one of oxjgen yieldmg two volnmes of gaseous water (true steam).
The noise of such explosions is caused by concussion hetween the particles of the gaseous body and those of air.
The force of the emlosion, or, in other words, the expansive force of the steam produced, is exceedingly slight, certainly very far below that necessary to break the fest-tuhe. Some force, however, is ex- erted, and hence the necefflity of the precaution previously suggested of allowing all the air which may be in a hydrogen-apparatus to escape before proceeding with the experiments. If a flame be ap- plied to the deHvery-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 f o the ground.
Hydrogen is a prominent constituent of all the substances used for producing artificial light, such as tallow, oil, and coal-gas. The ex- plosive force of large quantities, such as a roomful, of coal-gas and air, though vastly below that of an equal weight of gunpowder, is well known to be suEHcient at least to blow out that side of the room which offers least resistance.
The composition of water can be proved analytically as well as syntheticaily, a current of electricity decomposing it into its con- stituent gases, twice as much hydrogen as oxygen, by volume, being produced.
Combustion (from comhwro, to bum). — The cxpcriracuts with hydrogen and oxygen illustrate the true character of combustion. Whenever chemical combination is anfficiently intense to he accom- panied by heat and light, the materials are said to undergo combus- tion. Combustion only occurs at the iiue of contact of the combining bodies ; a jet of oxygen will bum in an atmosphere of hydrogen quite as easily as a jet of hydrogen in oxygen. A jet of air (diluted oxygen) will bum B£ readily in a jar of coal-gas as a jet of coal-gas \mras in air; each is combustible, each supports the combustion of the other. Hence the terms combustible aaa swpporter of combus- tion are purely conventional, and only applicable so long as the cir- cumstances under which they are applied remain the same. In the case of substances 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 bum in it as being combustible.
Structure of Flame. — A candle or oil-flame is a jet of gas intensely heated; the central portion consists of unbumt gas, the-next envelope is formed of partially burnt and very dense gaseous particles heated sufficiently high to give light, and tlie outer cone of completely bnrnt gaaes. Air made, by any mechanical ooiitrivsince of burner, to mix
id .y Google
PHOBriToaus. 31
■with the interiorof a flame at once bums up, or perhaps preTents the formation of dense gases, giving a hotter, but non-lnminons, jet. The "Buusett" gas-burners commonly used in chemical laboratories are constructed on this principle : their flame has the additional advan- tage of not yielding a deposition of soot.
In the Bunsen gas-burner a mixture of gas and air passes along a pipe. It only burns at the end, and not within the pipe, because Qie metal of the burner, by conducting heat away, cools the mixture below the temperature at which it can ignite. The Davy safety- lamp acta on the same principle : a wire-gauze cage surrounds an oil- flame ; an inflammable mixture of gas Tfire^mp) and air can pass through the gauze and catch fire and bum inside ; but the flame cannot bo communicated to the mixture outside, because the metal of the gauze cools down the gas below the temperature at which it
Properties {continued). — Hydrogen is the lightest sub- stance known. It was formerly used for filling balloons, but was soon superseded by coal-gas. Coal-gas is not so light as hydrogen, but 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 upwards. The hj'drogen will have escaped from the latter in a few seconds, whereas the former will still contain the gas after the lapse of some minutes. This may be proved by applying a lighted match to the mouths of the respective tubes.
The relative weight or specific gravity of oxygen is sixteen times that of hydrogen. A tube holding one grain of hydrogen will hold sixteen grains of oxygen. The relation of the weight of hydrogen to air is as 0.0693 to 1.0.
Mem. — It is desirable to. retain two tubes of hydrogen for nse in subsequent experiments.
Biffumon of Gases. — Hydrogen cannot be kept in such vessels as the inverted test-tube; for, though much lighter than air, it d^^^es downwards into the air, while the air, though much heavier, diffuaes upwards into the hydrogen. This power of diffusion is charaeteriBtio of all gases, and proceeds accormng to a fixed law, namely, " in in- verse proportion to the square root of the specific gravity of the gas" (Graham), Thus hydrogen diffuses four times faster than oxygen.
PHOSPHOEirS.
Appearance and Source. — Phosphorus {Flwsphfirus, B. P. and U. S. P.} is a solid element, in appearance and consistence resem- bling white wax ; but it gradually becomes yellow by exposure to Ught. It is a characteristic constituent of bones, and is always pre-
id .y Google
— Ph p fi d h a h
b te se
d te m d
w w^p]> or I )
p poa
p p —J) ap a h h
pea b q kl and y p b w h d
of porous (filter or blotting) paper ; place it oq a plate, and ignite by touching it with a, piece of warm wire or wood. Observe that the product of combustion is a dense white smoke, which must be confined at once by placing an inverted tumbler, test-glass, 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 few drops of water, and observe that some of the water is converted into steam, an effect due to the intense affinity with which the two combine,
The powder produced by the combustion of phosphorus is phos- phoric anhydride; the combination of the latter with the elementa of wat«r produces phosphoric acid, which dissolves in the water, form- ing a dilute solution of phosphoric acid. The Diluted Phosphoric Acid of the British and United States Pharmacopteias is a somewhat simitar solution, made, however, in a different way, and of a definite strength.
NITROGEir.
Source.- — The chief source of this gaseous element is the atmo- sphere, nearly four-flfths of which consists of nitrogen (the remaining fifth being almost entirely oxygen).
Preparation. — Bum apieceof dried phosphorus, the size of a pea, in a confined portion of air. The oxygen is thus removed, and nitrogen aione remains. The readiest mode of performing this expeiiment is to fix a piece of earthen- ware {the lid of a small porcelain crucible answers very well) on a piece of cork, so that it may float in a dish of water. Place the phosphorus on the lid, ignite by 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 of the glass may dip into the water. Let the arrangement rest for a short time for the fumes of phos- phoric anhydride to subside and dissolve in the water, and
id .y Google
NITROGEN. 23
then decant the gas into test-tubes in the manner already indicated.
Larger quantities are made in the same way. Other combustibles, such as sulphur or a candle, might be used to burn out the oxygen from a given quantity of air, but none answer so qnickly and com- pletely as phosphorus ; added to which, the product of their combiis- tion would not always be dissolved by water, but would remain with and contaminate the nitrogen.
Mem. — The statement concerning the composition of the air is roughly confirmed in preparing nitrogen, about one-fifth of the volume of fte air originally in the glass vessel having disappeared, its place being occupied by water tVom the dish.
Properties. — Like oxygen and hydrogen, nitrogen is in- visible, tasteless, and inodorous. It is only slightly soluble in water. It is distinguished from all other gases by the absence of any characteristic or positive properties. Apply a Same to some contained in a tube ; it will be found to be incombustible. Immerse a lighted match in the gas ; the flame is extinguished, showing that nitrogen is a non-sup- porter of combustion.
The chief ofBee of nitrogen in the air is to dilute the energetic oxygen, a mere mechanical mixture resulting. The chemical com- pounds of nitrogen and oxygen are numerous {vide Index). The compound formed by the nuion of nitrogen with hydrogen is gaseous
Nitrogen is fourteen times as heavy as hydrogen.
The air is nearly fourteen and a half (14.44) times as heavy as hydrogen. Its average composition, inclnding minor constituents, which will bo referred to subsequently, is as followB ; — ■
Composition of (he Atmosphere.
In !00 volumes.
Oxygen 20.65
Nitrogen 77.95
Carbonic acid gas .... .04
Aqueous vapor 1.40
Nitric acid 1
Ammonia > traces.
Carbnretted hydrogen . . . . ) Sulphuretted hydrogen . . . \ traces in Sulphurous acid j towns.
The above proportions are by volume. By weight there will be nearly 23 parts of oxygen to nearly 77 of nitrogen, oxygen being the heavier in the ratio of 16 to 14. Ozone [vide Index) is also said to be a normal constituent of air.
id .y Google
ON-METALLIC
Preparation. — About a quarter of an ounce of salt and the same amount of black oxide of manganese are placed in a test-tube with sufficient water to cover them; on adding a small quantity of sulphuric acid, the evolution of chlorine commences.
As the action of tie snlphnric acid on the salt in the above pro- cess is raainlj to give hydrochloric acid, the latter acid and the black oxide of manganese may be nsed in making the gas, instead of salt, sulphuric a«id, and black oxide of manganese. This is tie process of the British and United States Pharmacopceias.
Larger quwntitim may be made from hydrochloric acid and black oxide of manganese (about 4 parts to 1) in a Florence flask, fitted with a delivery-tube, the flask being supported over a flame by the ring of a retorf-stand or any similar mecnanical contrivance.
Mem. — Flasks and similar glass vessels are less liable to iracture if protected from the direct action of the flame by being placed on a piece of wire gauze 2 to 4 inches square, or on a aawHath, that is, a saucer-shaped tray of sheet iron, on which a thin layer of sand is placed.
Collection and Properties. — Chlorine is a most suffo- cating gas. Great care must consequently be observed in experimenting with this element. As soon as its pene- trating odor indicates that it is escaping from the test- tube, the cork and delivery-tube should be fitted on, and the gas allowed to pass to the bottom of another test-tube half filled with water. When thirty or forty small bubbles have passed, their evolution being assisted by slightly heating the gene rating-tube, the latter should be removed to the cupboard usually provided in laboratories for per- forming operations with noxious gases, or dismounted, and the contents washed away. The water in the collect- ing-tube will now be found to smell of the gas, chlorine being, in fact, soluble in about half its bulk of water. Chlorine- water is ofRcial* in the British and United
* The Pharmaonpteia and all in it are official (o^ce, Pr. from 1.. officiam, an office). There are many things which in pharmacy are officinal. (Fr. from L. o^cina, a shop) but not official. To restrict the word offieiaai, first, to the contents of a pharmacist's sliop, and, seeond, to that portion of the contents whicli is Pharmacopceial, ts radically wrong, and should be a^'oided.
id, Google
CUEOItlNE. as
States Pharma cop (Bias (Liquor Chlori, B. P., Aqua Chlo- rinii, TJ. S. P.).
The Va^or (Mori, B. P., or Inhalation of Chlorine, ia simply moist chlorinated lime so placed that some of the chlorine given off m^ be inhaled.
During theae manipulations the operator will have noticed that chlorine is of a light green color. That tint is readily observed when the gas is collected in large vessels. As it is soluble in water (2J vols, in 1 vol. at C0° F.), it cannot be economically stored over that liquid. Being, however, nearly twice and a half as heavy as air, it may be collected by simply allowing the deliverj-tube to pass to the bottom of the test-tube or dry bottle.
The distinctive property of chlorine is its bkaching'- power. Prepare some colored liquid by placing a few chips of logwood or other dyciog material in a tcst-tubo half fail of hot water. Pour off some of this red decoction into another tube, add a few drops of the chlorine- water, aud note how rapidly the color is destroyed..
Chlorine readily decomposes nosious gases, and benee is one of the most powerful of the deodorizers, ifsed in excess it arrests and prevents putrefaction, hence it is one of the best of dimnfeciants.
Combination of Hydrogen with Chlorine, forming Hydro- chloric Acid. — If an opportunity occurs of generating the gas 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 previous operation, is filled with the gas. The hydrogen-tube ia then inverted over that containing the chlorine, the mouths being kept together by encircling them with a finger. After the gases have mixed, the months of the tubes are quickly in succession brought near a flame, when explosion occurs, and fumes of hydrochloric acid gas arc formed. The hydrochloric acid of pharmacy (Acidum Hydrochloricum, B. P., Acidum Muriaticum, TJ. S.P.) is a solution of this gas (made in a more economi- cal way) in water.
The foregoing experiment affords evidence of the powerful affinity of chlorine and hydrogen for each other.- Chlorine dissolved in water wiU, in sunlight, slowly remove hydrogen from some of the water and liberate oxygen. The bleaching-power of chlorine is generally referred to this indirect oxidizing effiict it produces in presence of water ; for dry chlorine docs not bleach.
3, half times as heavy as
id .y Google
hhia- ELEMENTS.
SULPHUR, CAHBON, IODINE.
The phi/sical properties of those elements are probably familiar. Their loading chemical. characters will also be understood when a few facts concemiDg each are made the eubject of experiment.
Sulphur, — Born a small piece of sulphur ; a penetrating odor is produced, due to the formation of a eolorleaa gas, the same as that formed on igniting a common snlphur- tipped lucifer match.
This product is a perfectly definite chemical compoTind of the oxygen of the air with the sulphur. It ia termed smphnroua acid gas.
Carbon ia familiar in the forms of soot, coke, charcoal, graphite (plumbago, wrongly termed blacklead), and dia- mond. The presence of carbon in wood, and in other vegetable and animal matter, ia at once rendered evident by heat. Place a little tartaric acid on the end of a knife in a flame ; the blackening that occurs is due to the sepa- ration of carbon. The black matter at the extremity of a piece of half-burned wood is also carbon.
Oarbon, like hydrogen, phosphoma, and sulphur, has a great afBnity for oxygen at high temperatures. A striking evidence of that affinity ia the evolution of sufficient heat to make the materials concerned red or even white-hot. When ignited in the dilute oxygen of the air, carbon simply bums with a moderate ^low, as seen in an ordinary coke or charcoal fire, but when ignited m pure oxygen, the intensity of its combination is greatly e^ted. The^produet of the combination of the two elements, if the oxygen be in excess, is an invisible gaseous body termed carbonie acid gas ; if the carbon be in excess, another invisible gas termed carbonic oxide results.
Iodine. — The main chemical characteristic of iodine is its great affinity for metals. Place a piece of iodine, about the size of a pea, in a test-tnbe with a small quantity of water, and- add a few iron-fliings or small nails. On gently warming this mechanical mixture, or even shaking if longer time be allowed, the color and odor of the iodine disap- pear ; it has chemically combined with the iron ; a chemical compound has been produced. If the solution be filtered, a clear aqueous solution of the compound of the two ele- ments is obtained.
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 Iodide of Iron of pharmacy [Syi'Upus Ferri TocUdi, B. P.
id .y Google
HE ELEMENTS, THEIR STMBO
27
and TJ. S, P.). A strong solution mixed with sugar and liquorice- root (sugar, marslimallow, gum Arabic, and reduced iron, TJ. 8. P.) constitutes the corresponding Pill (Piliiia Ferri lodidi, B. P. and IJ. 8. P.). The solid iodide {Fern Io<U<Mim, B. P.) is obtained on removing the water of the above solution by evaporation.
THE ELEMENTS, THEIR STMBOLS, Ero.
From the foregoing statements a general idea will have been obtained of the nature of several of lie more frequently occurring elements. Some addifional facta concerning them may be gathered from the following Table, which gives the name in ftiU, the symbol (or short-hand character*} of the name, and its origin.
Por the purposes of study the elements may be divided into three classes, viz., those frequently used in pharmacy, those seldom, and those never used.
Sj-mbo'
Osj-gen
Hydrogen.,..
Mitrogen
Carbon
Chlorine
Iodine
Sulplinr
Phosphorus .
Potassium ,. (Kaliara.)
From JJ&! (oxus) acid, and yjits-ij (gene- sia) generation, i.e., generator of acids. It was supposed to enter into ths composition of ail aoids when first discovered.
From iisa/ (hudar) viaier, and yinrit (ge- nesis) generation, in allusion to tbe product of its ooiubaation in air.
FromwTfot (nitron), and j.irEri; (geuaais),
From corfto, con?, which is chiefly oarbon.
From x*"/^t (ohlOros) green, tha color of thia element.
From fov (ion) a violet, and iTSot (eiios) liheness, in referenoe to the color of its va-
From sal a salt, and leSp (pur) Jire, indi- cating its combustible qualities. Its com' mon name, brimaione, has the same mean- ing, being the slightly altered Saxon word hrynstone, i. a., hnmstone.
^{ (phos) light, and ^pti (phecein) to hear. The light it emits may be aeeu on exposing- it in a dark room,
Kaliam, from kali, Arabic for ashea. Mann- faotories in whioh oertain compounds of potassium and allied sodium salts are made are called alkali-works to this day. Potas- sium, ivora pot-ash ; so called because ob- tained by evaporating the lisivium of wood-ashes in pots. From auch ashes the elijment was first obtained, heuoe the name.
e than the short-hand character,
id .y Google
ELEMENTS, THE
|
..... |
Symbol |
..„„»...,.„., |
|
Sodium |
Na |
Nalrium, from natron, the old name for |
|
(Natiium.) |
oertain natural deposits of oarbonale of sodium. Sodium, fiom soda ask or sod-ash, sods of marina plants Ihese weie the sources of the metal |
|
|
Ammonium |
Am |
This body is not an element, but its |
|
(t^HJ |
mp ants esiat in all ammoniaoal salts, 1 ppatently play the part ot such ele- m t s potassium and sodium Sal am- m (chloride ot ammonium) was Erst b d from near the temple of Jupiter Amm in Libya ; henoe the name. |
|
|
Barium |
Ba |
F Bcifii (barus) lieav;/, in allusion to |
|
th li gh speoifie gravity of "heavy spar," |
||
|
h m t common of the barium minerals. |
||
|
Caloiura |
Ca Mg |
C I lime, the oxide of oalcium. |
|
Magnesium |
F m Magnesia, tlie name of the town (iii |
|
|
A M uor) neat which the substance now |
||
|
11 d n f B b te t magn --a-'waa |
||
|
fi td 0 d |
||
|
Iron |
Fe |
Th pell g f m th S I th p it p 1 hi) f m th k d d |
|
(F«rrum.) |
||
|
Gothic th d i ti u k w |
||
|
to the auth |
||
|
Aluminium |
Al |
The met 11 b f 1 m w t fi t confonaded wltl tl t Iph t f which w h 1 ra f th R m d was 80 call d U t t p partiBB, S m I h |
|
Zinc |
Zn |
Tha der t f th w d i a k a |
|
to the auth |
||
|
Arseuionm |
As |
"ApriwuSv (arsenikon), the Greek name for orpiment, a sulphide of arseaicum. Com- mon white arsenic is an oxide of araenionm. |
|
Autlmocy |
Sb |
iTie. (atibi), or <rT.>^.i (stimmi) was the |
|
(StilJium.) |
Greek name for the native sulphide of an- timony. The word antimomj is said to be derived from ivri (anti) against, and moine, French for monk, from the fact that certain monks were poisoned by it. |
|
|
Copper |
Cu |
From Cyprus, the name of the Mediterra- |
|
(Cuprum) |
nean island where this metal was first worked. The Latin word is exprassive of "some- thing heavy," and the Sasou la:d has a |
|
|
Lead |
Pb |
|
|
(Plumbum.) |
||
|
similar signification. |
id, Google
THE ELEMENTS, THEIR SYJIUOLH, ETC,
|
«a,ua. |
Sj,ul.ol |
I>e,.™,i„«ofnam.. |
|
Mercury (Hjdrargyram.) |
Hg Ag |
Hi/drargymia, from Jt«^ (hudOr) uraier, and Ipj^ufo; (arguroH) siVKei-, In allusion toils liquid aud Inatrous oliaraBtars. Mercary, of ita snseeptlbility of motion. The old name gmckiiher also indioataa ita ready mobility and argentine appearanoe. 'Afyvfdi (arguros) silver, from ifyit (firgos) white. Words resembling the term siliier oocnr in several languages, and iudioate a wLite appearanoe. |
|
(AigeLlniD.) |
The following are names of some of the less frequently occurring elements, compounds of which, however, are alluded to in the Britiah and U. S. Pliarmacoposias, or met with in pharmacy.
|
..... |
„.,., |
Derlvaionofanme. |
|
Eromlne |
Br Fl Bo Si I Br Ce |
From flf5^oi{br0mos),asi!K£, It has an intolerable odor. Pluo to flov,. Fluofide of oaloiuro, Ita tallurglo opei'ations. From borak or baurak, the Arabic name of borax, the substance from whioh the ele- ment was first obtained. Prom ailex, Latin iovjiint, which is nearly- all silica Can oxide of silicon). From xiitxK (lithelos) stony. In allusion to dom only. This name is commemorative of Stron- tian, a mining village In Argyleahire, Soot- land, in the neighborhood of which the mineral known as slroniianite or carbonate of strontium was first found. |
|
lithium |
||
|
Strontium |
||
|
planet Ceres, wMob was discovered on Jan. 1, 1801. The oxalate, CeCjO„3HjO, is official, bat seldom used. |
id, Google
ELEJIENTS, THEIR BYMliOl.
From xf^f"' (clirOma) color, in allusiou to the charnotei'iEtio appearance of its salts.
Probably a mere tranapoBitioii and repeti- tion of moat of tiie letters of the nord magnesia, with whose componiids those of manganese were confounded till the year 1740.
Cobaltis or Kobold was the name of a de- mon suppoaad to inhabit the mines of Germany. The ores of cobalt were formerly troublesome to the German miners, and hence received tlie name their metallio radical now bears.
Nickel, from nil, is a popular German term for worlhless. The mineral now known as nickel ore was formerly called by the Germans Kap/eTnickel,/alse copper, on ac- it of its resemblance to copper (_Kup/er') When a new metallic element was
1 the o.
, the u
tained.
Both, words are poaaibly corrnptions of the old British word aiaen, or the Saxon word alan, a stone. Tin was first discovered
1 Cornwall, and the ore Can oxide) is called iiaatone to the present day.
Aurum (Latin) from a Hebrew word sig- nifying tlie color of fire.
Gold, an old Saxon word espressive of yelloB!, the oolor of this metal.
From plaiiaa (Spanish), diminatire of plata, silver, in allusion to Its inferiority in lustre, but otherwise general resemblance
Slightly altered fiom the German Wis- muf/i, derived from Wiesemalte "a beauti- ful meadow,'' a name given to ifroriginally by the old miners in allusion to the pret- tily variegated tinta presented by the freshly exposed surface of this crystalline
KiV'^ (Eadmeia) was the ancient name 'oalamine{earbonoteof zinc), with which Le of cadmium was long confounded, 0 often occurring together.
Gold, Platinum, Tin, and Silicon are here classed with the les important elements, because their compounds are seldom used ii pharmacy.
id .y Google
QL'ESTIOKS ANT) EXERCISES. SI
It will te noticed that the sjoibol of an element ia simply the lu'St letter of its Latin name, which, is generally tlie same aa ia the Eng- lish. Where two oamM begin with the same letter, the leaa import- ant has an additional letter added.
QUESTIONS AND EXERCISES.
1. Of how many eleiaents ia terrestrial matter composed?
2. In what state do the elements occur in nature ?
3. State the difference between theorfand the scj'enceof chemistry. 4 What is the difference between an element and a compound?
5. Enumerate the chief non-metallic elements.
6. Describe a process for the preparation of oiygen. 1. How are gases usually stored?
8. Mention the chief properties of oxygen.
9. What is the source of animal warmth !
10. State the proportion of oxygen in air.
11. Ia the proportion constant, and why ?
12. Give ft method for the elimination of hydrogen from water.
13. State the properties of hydrogen.
14. Why is a mixture of hydrogen and air explosive 1
15. Explain the effects producible by the ignition of large qnan- ties of coal-gas and air.
16. What is the nature of combustion ?
n. Give the conventional meanings of the terms combustible and supporter of combustion.
18. Describe the stj-ucture of ttame.
19. State the principle of the Davy safety-lamp.
20. To what extent is hydrogen lighter than oxygen ?
21. What do vou mean by dtffunon of gases 1
22. State Graham's law concerning diffusion.
23. Name tie source of phosphorus, and describe its appeamnce.
24. Why does phosphorus bum in air ?
25. What remains when ignited phosphorus has removed all the oxygen from a confined portion of air?
26. Mention the properties of nitrogen.
27. What office is fulfilled by the nitrogen of air ?
28. State the centesimal proportions of the chief constituents of air, by volume.
29. Mention the minor or occasional constituents of air.
30. What is the proportion by weight of nitrogen to oxygen in the atmosphere ?
31. Give the specific gravity of nitrogen.
32. How is chlorine prepared?
33. Enumerate the properties of chlorine.
34. Define the terms deodorizer and disinfectwnt.
35. ;^q)lain the bleaching effect of chlorine.
36. What proportion of hydrogen to chlorine is neccssai'j for the formation of hydrochloric acid gaa?
37. State the prominent characters of sulphur.
38. State the prominent characters of carbon.
id .y Google
32 PRINOTPLES or CUEMIOAL PHILOSOPHY.
39. State the prominent characters of iodine.
40. Give the derivations of the names of some of the elements.
41. What are the symbols of oxygen, hydrogen, nitrogen, carbon, chlorine, iodine, sulphur, phosphorus f
THE GBNEEAL PEINOIPLRS OF CHEMICAL PHILOSOPHY.
The learner may now proceed to study the manner in which sub- stances react chemically with each other.
That this tendency to act, when the bodies are brought into con- tact under iayorable cironmstancea, exists, ia obTiona from the preceding experiments, and indeed from the operations of every-day life. In a common Are. coal needs only to have its temperatnre slightly raised to afford it an opportunity of showing the liking or- affinity which it and the oxygen of the air have for each other. The evolution of heat in this instance is only one of the ineidenta of the action. The presence of. chimneys and the means of ventilation are ac^uncts to a fire, which should at once suggest that there are stUl more deeply hidden incidents of the mutual action of coal and air. Such a formation of complex bodiea from simple ones, and the reso- lution of complex into sunple bodies, is constantly occurring in na- ture. From the air and the earth vegetables construct complex matters, which are resolved into their original simple forms after having served as food for animals. To discover and remember the laws which govern these transformations, the general student of Chemistry educes elements from compounds, and bmlds np com- pounds from elements — the student oi Pharmaceutical Chemistry restricting his attention to those with which he is more immediately concerned.
Thia tendency to combination, being a prominent feature in every- thing material, the mind naturally assumes the existence of some sort of power or energy in matter by which its particles are bound together, a sort of force or affinity which only needs opportunity to manifest itself. In order to distinguish thi^ force from those of gravitation, heat, light, electricity, and magnetism, it is called chemi- cal force or chemical affinity. It is a peculiar and distinctive func- tion of the chemical force that it confers on bodies joined by its means properties entirely different ft«m their constituents : for ex- ample, a mere mixture of hydrogen and oxygen has all the characters, or the mean of the characters, of those gases, but a chemical combi- nation of hydrogen and oxygen (water) has the qualities of neither element, but fresh properties altogether.
Ohemicai. Force.
Having thus acquired a knowledge of certain facta concernmg
each element, the experiments already performed may be ieviewed
in order to obtain a clear idea of the manner in which ilimiicil lub
id, Google
CHEMICAL FORCE. 33
stancea are believed by philosophers to unite, or influence eaoh other, and to learn how memoranda concerning those actions are best re- corded on paper and in the mind.
The student must look npon every particle of matter, solid, liquid, or gaseous, as being absolutely indesiructible, and as being the Beat of a certain amount of a peculiar attractive energy or force, com- monly termed chemical afflnitj;. This affinity is so natural that probably separate or single particles cannot exist alone for an instant, and, if liberated from their combinations, immediately reunite in pairs or groups. Apparently the natural affinity of any particle is for a particle of another element, but, if the latter is not at hand, the particle instantly combines with a particle of the same element as itself; hence, doubtless, the greater frequency in nature of com- pounds (wood, stone, water, etc.) than of elements (hydrogen, sul- phur, gold, etc*). The exertion of chemical affinity (the force or power by wldch this indestructible matter suffers change of form or condition) is only possible when the substances in question are in close coctaet Thus, it was necKSary to bring the oxygen, hjdrogen, phosphorus, chlorine, sulphur, carbon, iodine, and iron into intimate
* The grounds for tlie statement that elements never exist In single partioles, but that, if the particle (the most minute volume imagiu- able) of an element has not the opportunity of oombinlng with a particle of another elemeiit, it will oombine with another particle of like nature to itaolf, are shortly as follows ; Equal volumes of ele- mentary or oompound gases, nnder similar pressure, expand equally when heated, and contract equally when cooled ; equal volumes must, therefore, be similarly constituted, must contain an equal number of moleoulea (the diminutive of mole or mass — literally, little masses), all of the same size. For example, in a previous esperimeut (p. 25) a test^tubeful of chlorine gas and one of hydrogen gave on mixture and explosion two test-tubefnls of hydrochloric acid gas. Now it could be easily demonstrated that these three gases expand equally on the addition of heat, and contract equally on its abstraction. Hence the inference that the number and size of the molecules of eacli volume are similar. We have no conception of the actual number of molecules of a gaa that a test-tube, or any other vessel, is capable of containing ; but whatever It be, that number is constant for all gases- Imagine that it is 1000 ; then 1000 of hydrogen and 1000 of chlorine have given 2000 of hydroobloric acid. But each of these 2000 mole- oules of hydrochloric acid contains a particle of hydrogen and a par- ticle of chlorine. Therefore the 1000 moiecales of hydrogen must have contained 2000 particles, and the 1000 molecules of chlorine, 2000 par- ticles of chlorine. In other words, every molecule of an elementary gas consists of two partioles, or, as they will be termed on a subse- quent page, atoms («to^o(, indivisible, from the privative «, a, and Tt;uv«, temno, to cut). Sea also Hofmann's 'Modem Chemistry,' pp. 136-162.)
Additional evidence of the existence of molecnies of elements is found in the fact that at the moment certain elements are liberated from their combination, they are far more active than afterwards, when the atoms have probably united to form moleoutes. This highly aotlve condition is often spoken of as the nascent state.
id .y Google
34 CHEMICAL FORCE AND CHEMICAL NOTATION.
contact before reaction occurred. The exact natore of these actiona, as indeed of all in which Bubstances act chemically (i.e., with obvi- ous alteration of properties in the product), would seem to be an interchange, moat generally a mutual one, of the particles of which the bodies consist,
OhBMIOAL FokCB ANn ChEMICAI. NOTAITON.
As an example of chemical action and the best of expressing it by notation, take the experiment in which two vi iiinea of hydrogen and one of oxygen were caused to combine. Tub production of flame and noiee proved that chemical action of some kind had taken place ; had the experiment been performed in dry TteselB, evidence of the precise action would have been found in the bedewment or moisture produced by the condensation of the water on the sides of the tube. Similar evidence was afforded on holding a cool glass surface over the hydrogen-flame. The action is ex- pressed in the following way, the symbols or short-hand characters previously referred to (p. 27) being now invested with a second func- tion, namely, that of mdioating quantity by measure or volume; single letters indicate single and equal volumes of the respective
Hj + 0 = H,0. Or more correctly, becanse eshibiting the natural occurrence ol of particles,
2H, -f- 05=2H,0. Here the symbol H, and 0, or rather 2Hj and Oj, standing alone indicate the state of things prior to the experiment: in juxtaposition thus, .HjO, they indicate the result. Two molecules of hydrogen (2Hi) and one of oxygen (0,) give two of water (2HjO).
A small figure mnltiplies symbols only, a large figure multiplies any symbols, small figures, or formulie before which it may be placed. E is a symbol, HjO is afomvula.
The sign plus (-|-J between tho symbols Hj and 0 indicates that the one element is simply mised with or added to the other.
The sign [=), or equal, has the usual signification given to it in arithmetic.
Instead of an equation, a diagram may be employed for czpress- ing the above and similar actions on paper. Thus : —
Here lines indicate the paths taken by (he respective substances.
The foregoing aggregation of symbols or short-hand characters, viz., II5O, is, then, a convenient picture of the facts that have already come before ua, viz., that water is formed of the elements hydrogen,
id .y Google
CliEMIOAL FORCE AND CHEMICAL NOTATION. 35
H, and oxjgen, O, and, moreover, that it is formed of two nieasiirca or volumes of hydrogen, II,, and one of oxjgen, O.* These sym- bols so arranged have a deeper signification still, as wiU boou be apparent.
Another experiment already performed, illustrating the character of the manifeBtations of chemical force and its symbolic expression, was that in which the red-hot carbon of wood was plunged into oxy- gen. The evidence of chemical action in that case was the sudden iniammation of the carbonaceous extremity of the wood. The parti- cles of carbon and oxygen having intense attraction or affinity for eaflh other at that temperature, rushed together so impetuously as suddenly to produce a large additional quantity of heat, an amount sufficient to cause the particles to emit an intense white light. Here it may be again remarked that this attraction, distinguished from alt others by the term chemical, is the only form of attraction by which the properties of the product are renamed totally differmd from tkoae of its constititents. The action between carbon and oxygen is expressed on paper in either of the following ways :—
Cj + 20, = 200^.
CO t is the formula of the well-known gaseous body commonly termed carbonic acid gas.
The reader should here draw for himself similar equations or dia- grams, showing the formation of the four other bodies produced — namely, hydrochloric acid (HOI), phosphoric anhydride (PjOj), sul- phurous acid gas (SOj), and iodide of iron (I"elj), submitting the same, if possible, to a tuter or other authority to assure himself of their correctness.
^ote. In the foregoing experiments several illustrations occur of
the formations of compounds having the gaseous, liquid, and solid conditions, in one of which three forms aU matter in the uaiveree exists.
• Turtber, the formula H^O Tepressnts two volnmes of water in the state of gas ; indeed all such formula represent two gaseous volumea 6f the reepeotive vaporizable compounds. This auhjoot will be again alluded to in connection with the speciflo gravity of gases,
f Tlie formula CO, indicates that two volumes of carbonic aoid gas contain one volume of carbon gas and two volumes oxygen gas, the three volumea being condensed to two. But we have only indirect evidence of the relation of the volnme of carbon gas to oxygen gas in oarbouio acid gas, free carbon never having been obtained in the gaseous oondition ; still, the evidenoe, tbongh indirect, is suffioiently good to warrant obemlsts in according to these single letters or short- hand characters the function of representing equal gaseous vohinie* of elementB at any given temperature.
id .y Google
or CIIEMICA
Laws op Chemical Combination and the Atomic TnEOnY.
Chemistry, as a science, is little more tlian one hundred years old. Tery many of the facts and operations we now terra chemical have been known aa isolated items of knowledge for centuries. The ancient Egyptians made glass, vitriol, soap, and vinegar ; and the Greeks started the idea that matter was composed of elements (eariJi, air, fire, and wat«r). But the great general principles which inter- lace and hind together separate facts, those which, from their exten- sive application and importance, are denominated laws, have all been bronght to light since the year 1770. Between 178S and 1800, Bryan Higgins, William Higgins, Eichter, and Proust, traced with more or leas accuracy the following truths ; — ■
1st. A definite compound always contains the same elements in the same proportions (by weight as well as by volume} — the law of Constant Proportions.
2d. Two elements uniting in more than one proportion [either by weight or volume) do so in simple multiples— the law of Multiple Proportions.
3d. The proportions (weight o
bodies nnite with a third a._ j,. ,j, ,.„
unite with each other^ — the law of Keciprocal Proportioi
In 180;J-8 Dalton offered an explanation of these laws, gave a probable reason why they should be as stated, and indeed was the first to set them forth in a cleat and definite manner.
Dalton sitggested that matter was not infinitely divisible, bvt composed of minvte panicles or atoms having ow invariable character. This hypothesis ("atomic theory," as it is generally termed) being accepted, the comprehension of wie three laws becomes extremely simple. A compound (water, for example,) being invari- ably composed of invariable atoms, it follows that it itself must be invariable. One atom of a given element, a, and groups of two or more atoms of the same element, each atom invariable in weight, uniting with a single invariable atom of another element, 6, and forming one, two, or moro distinct compounds {e.g., carbonic oxide gas, 12 parts carbon and 16 oxygen; and carbonic acid gas, 12 parts carbon and 32 oxygen), it follows that these componnds will contain a common proportion of one element, 6, and simple multiple propor- tions of the other, a. Single atoms of different elements, a, b, c, uniting consecutively with a single atom of any common element, d, (ad, ba, cd,) and being capable of union amongst themselves, it follows that resulting compounds, ab, ac, be, will contain jiroportions of each constituent, a, J>, c, identical with the proportions in which those conatituentB united with the common element, d. Since Dalton's time the tendency of speculation has been towards the unity of mat^ ter — the identity of all elements ; to regard the so-called aiom^ of different elements as being composed of identical vltimates in a state of vibl'ation, the rate of vibration of groups of ultimates alone causing the different properties of the so^aUed elements. Front's hypothesis that all atomic weights are multiples of that of hydrogen, ana Duraaa's modification that every atomic weight is a multiple of
id .y Google
ATOMIC WEIGHTS ''I
that of an unkuown body whose atomi w ghl 2 Id h
strongly supported this idea of chemical f bcbt md f motion, had not the rcBearches of chemi ta pe allj th f ht demoDBtrated tliat neither hypothesis ha an hdwff d ill tact. At present therefore, so far as 1 m t y ib n d Ih matter-and-motion theory of the constitnt f h w Id p-
!)orted by experimental proof — belongs t <h g f p \ ation. Hence we may coatiuue to belie at m di g th
perhaps rather as " particles of matter wh h d g th d
sion in chemical metamorphoses" (Keknl ) th as b 1 tely d aible. The study of these atoms is th bj t f ?i« ( ^ — th natural properties of substances in mass d th 1 ti t h at light, electricity, magnetism and gravitat 1 1 t g th I J t
at physics (from firu, phusis, nature}. Pos bly m g nd mpl truth underlies and connects chemical and physical facta, but at pre- sent there is no indication of such a law or laws.
An atom is the smallest portion of matter which can exist in a state of combination ; a molecule, the smallest portion which can exist in the free stale. The symbol of an element is intended, as a third function (c), to indicate this atom ; thus H and CI respectively indicate one atom of hydrogen and one atom of chlorine. A symbol also indicates, as we have seen, (o) the name of an element and (6) one volume of that element in the state of gas, sapposing it to be capable of existing in that form. Two symbolical letters indicate two atoms or volumes — -that is, one molecule — thus 00, or rather Oj. The formula of a compound always mdicates (a) the mole- cvie, (&) two volttmes of the compound in the gaseous stale, and ( c) the number of atoms and (d) gaseous volmties concerned in the formation of tlie Tuolecuh. Thus HOI is the formtda of the mole- cule of a compound containing one atom each of the elements hydrogen and chlorine. Further, like the formulte of all molecules, it is the picture of two volumes of hydrochloric acid, one volume being chlorine, and the other hydrogen. It shows, therefore, that the volume of chlorine and the volume of hydrogen suffered no condensation on combining to form a molecule compounded of both. Similarly HjO indicates the existence of a body (water) containing hydrogen and oxygen, the molecule containing two atoms of H to one of 0 (HjO), two volumes of which body in the gaseous state {('. e. steam) were formed from two volumes of hycbogen and one volume of oxygen, the three volumes therefore suffering condensation to two-thirds their bulk.
Atomic Wbhshts. If there be such things as atoms (and the mind necessarily assumes their existence), they must have weight. What are these weights ? Firet, they are represented by the smallest proportion (relative to 1 part of hydrogen) in which they migrate from compound to com{iound. Thus 1 part by weight of hydrogen can be eliminated from 18 similat
Sarlfi ofwater by action of certain metals, leaving 1 of hydrogen and S of oxygen combined with the metal. Prom the latter compound 1 more of hydrogen is eliminated by a second experiment with more metal, leaving 10 of oxygen combined with the metal. In these and
id .y Google
other well-knowQ reactions 16 parts of oxygen take -part in tlie various operations ; 16, therefore, is the probatle atomic weight of oxygen. And so with other elements and radicals. Secondly, the
IS of those elements differ in weight. For equal yolumes ci tain an equal number of molecules equal in size, and each molecule is composed of two atoms; so that equal Tolumes contain an equal number of atoms. Now, bulk for balk, chlorine ia thirty-fiTe and a half (35.5) times as heavy as hydrogen; so that the molecule of chlorine must be 35.5 times the weight of the molecule of hydrogen; for molecules are eijual in bulk. And as the molecules of'^chlorine and hydrogen eontam two atoms each, the atom of chlorine must be 35.5 times as heayy as that of hydrogen. The actual weight of atoms can never he ascertained, but that is of little consequence if we cau only determine, with exactitude, their comparative weights. Ooraparing, then, all atomic weights, sometimes obscurely termed equivalents, with eaob other and selecting- hydrogen as the standard ot^ comparison (because it is the lightest body known, and therefore, probably, will have the smallest atomic weight), and assigning to it the number 1, we see that the atomic weight of chlorine wi!l be represented by the number 35,6, By parity of reasoning the atomic weight of oxygen is 16 ; for oxygen is found, by experiment, to be 16 times as heavy as hydrogen. Similarly the atomic weight of nitrogen is found to be 14 The atomic weight of carbon is 12,— not because its vapor has been proved to be 12 times as heavy as hydrogen, for it has never yet been converted into the gaseous state, but because no' gaseous compound of carbon, which has b ly d h b
found to contain in 2 volumes [one of which, fhydrg Idw gh
1 part) less than 12 parts of carbon.
By thus weighing equal volumes of gase 1 m t q 1
volumes of gaseous compounds of non-volatd ltd taining by analysis the proportion of the non- 1 til 1 m t wh atomic weight is being sought, to the volatil 1 t wh tom weight is known, the atomic weights of a larg mb f th 1 m ta have been determined. Some of the elements, however, do not form volatile compounds of any kind ; the stated atomic weights of these elements, therefore, are at present simply the proportions by weight in which they combine with or displace elements whose atomic weights have been determined, the proportion being in most cases checked by isomorphic considerations and the relation of the element to other forces, especially heat.*
* IsoTaorphavs bodies (from litt, iso', equal, and fisfM, morphe. form) are thosenhich are similar in the shape of tlieir crystals. The identity in crysUlllne form is so commonly assooiated with similarity of oon- stitntion that non -crystal line Eubstanoes resembling eaoh other in structure are often regarded as Isomorphous. When one element unites with another in mora than one proportion, and consequently iii atomic weight is uuteitain, the isomorphism of either of its com- pounds with some other compound of known ooiistitution is usually Aicept-d as decisive evidence as to wliicli proportion is atomio.
id, Google
QUANTIVALBNOE. S9
The meight of the molecide (molccnlar weight) is simply the sum of the weights of its atoms ; thus
0,=32, C1,='!1,H,0=18, HC1=36.5.
Memoranda. — Though the symholsof the commoa elements should be oommitted to memory, their atomic weight need be sought out only as occasion may arise. A complete Table will he found at the end of the volume.
Gonatruetion. of Formvlce.—T\iG composition of hydrochloric acid (HCl), water (HjO), ammonia (NH„), carbonic acid gas (OOj), or any other compound, as well as the weight of an element that may be concerned' m its formation, cannot be ascertained by actual ex- periment until the student is far advanced in practical chemistry^ nntil he is able tQ analyze not only qualitatively, but, by help of a balance, qunntitativdy. The percentage composition of a substance having Been determined by quantitative analysis, its formula is constructed by help of the foregoing and other theoretical considera- tions. The correctness of such formulie can be verified by expert analysts, but must be taken for granted by learners.
QUANTIVALENCE.
Turning from the weights of atoms, their value may now be con- sidered; flieir quantivalertce (from quantitas, qnantity, and valens, being worth) may be stated. Here again hydrogen is conventionally adopted as the standard of comparison. Oxygen in its relations to hydrogen is bivalent (pronooneea thus, biv'-a-lent; of double worth, from bii, twice, and vaims); an atom of it will displace two atoms of hydrogen, or combine with the same number; nitogen is usually trivalent (friv'-a-lent; ii:om ires, three, and valena) ; and carbon quad-«v'-a-Ient {from qiiatuor, four, or quater, four times, and valetis]. Chlorine, iodine, and bromine, as well as potassium, sodium, and silver among the metals, are, like hydrogen, univalent (n-ntv'-a- lent; from ttnus, one, and valens). Barium, strontium, calcinra, magnesium, zinc, cadmium, mercury, and copper, like oxygen, are
i,...,...± T....._i. .- — j; J v: '^ Jike ""'"^
bivalent. Phosphorus, arsenicum, antimony, and bismuth, Tike nitro- gen, nsnally exhibit trivalent properties; but the composition of certain compounds of these elements shows that the several atoms aresometiraes quinquivalent (qnin-qniv'-aJent; ^Min^Mjes, five times, and valens). Gold and boron are trivalent Silicon (the character- istic element of flint and sand), tin, aluminiam, platinum, and lead resemble carbon in being quadrivalent. Sulphur, chromium, manga- nese, iron, cobalt, and nickel are sesivalent (sex-iv'.A-lent ; from sea!, six, or sexies, sis times, and valens), but frequently exert only bivalent, trivalent, or quadrivalent activity. This quantivalence (quantriv'.*-lencei from quantifas, quantity, and valens), also some- what obscnrely termed atomicity, dynain/icity, and equivalence of elements, may be ascertained at any time on referring to the Table of the Elements at the end of this volume, where Roman numerals, I, ri. 111, rv, V, VI, are attached to the symbols of each element to indicate atomic univalence, bivalence, trivalenee, quadri valence, qujnquivalence, or sesivalence. Dashes (H', 0", N'") similar to
id .y Google
40 QUESTIONS AND BXEIICISES.
those used in accentuating words are often used instead of figures in expressing quanti valence. The quantivalence of elements, as tliey one after another come under notice, should he carefully cominitted to memory ; for the composition of compounds oaa often be thereby predicated with accuracy and remembered with ease. For instauce, the hydrogen compounds of chlorine, CI', oj^gen, 0", nitrogen, N'", and carbon, C"", will he respectively H'Ol, H',0", H',N"', and H'jC"", — one univalent atom, H', balancing or saturating one nniva- lent atom 01' ; two univalent atoms, H',, and one bivalent atom 0", saturating each other ; three univalent atoms, H',, and one atom having trivalent activity, N'''^ saturating each other ; and four univa- lent atoms, H^, and one ([uadrivalent atom, 0"", saturating each other. Carbonic acid gas, O^'O",, again, is a saturated molecule containing one quadrivalent and two bivalent atoms.
The doctrine of quanti valence will again be mentioned after the first six metala have been studied, when abundant illustrations of its applications will have occurred.
QUESTIONS AND EXERCISES.
42. Adduce familiar examples of the manifestation of chemical action.
43. What are the characteristics of the chemical force ? how is it distinguished from those of gravitation, heat, light, electricity, and magnetism ?
A. How may the results of chemical reactions be briefly expressed on paper ?
45. Illustral* the difference between chemical symbols andfonnulEB.
46. Give an equation expressive of tlie formation of water from its elements.
47. Draw a diagram showing the reaction that ensues when red- hot chaj-coal is plunged into oxygen gas.
48. Describe, by diagrams, the formation of HCl, PoOs, SO;, and Pelj.
49. How many chief laws regulate chemical combination?
50. State the law of constant proportions.
51. State the law of multiple proportions.
52. State the law of reciprocal proportions.
53. Describe the origin and nsea of the atomic theory.
54. Define the terms oiom and 'molecule.
55. In what do^ an atom of oxygen differ from a molecule ?
56. Describe the method of producing ammoniacal gas.
51. How many pints of their constituents are represented by one quart of hydrochloric acid gas, steam, and ammoniacal gas respec-
58. What i& aiomic weigTit f
59. Admitting the existence of atoms, and assigning the weight 1 to that of hydrogen, what ai-e the atomic weights of oxygen,
id .y Google
THE ELEMENTS AND THEIE COMPOUNDS. 41
cMorine, nitrogen, and cai'bon? Give reasons for considering the stated weights to be correct.
60. Define iBOmorphism.
61. Explain the value of isomorpliiBm as evidence of atomic weight.
62. What is to be nnderstood by qaanti valence ? Give examples of univalent, bivalent, trivalent, and quadrivalent atoms.
63. How may the quantivalence of an element bo expressed in its atomic symbol ?
64. Give the formulfe of two or tfiree compounds in which the quantivalence of one atom is saturated by tie combined quanti- valence of others.
THE ELEMENTS AND THEIE COMPOUNDS.
Having thus obtained a genera! idea of the nature of such elements as have especial interest fov the medical and pharmaceutical stndent, and which indeed are all with which any student of chemistry should at present occupy his attention, we may pass on to consider in detail the relations of the elements ta each other. The elementi them- selves, in the free condition, ate seldom used in medicine being nearly always associated, bound together by the chemical force in this combined condition, therefore, they must be studied Each combination of elements or chemical compound will in the following pages, he regarded as containing two parts or roits, tno ladicals : the one usually metallic, or. to speak more generally, basylons; the other commonly a non-metallic, simple or complex, acidulous radical. The basylous radicals, or metals, will be considered first, the acidu- lous radicals aftem'ards.. Each radical will be studied from two points of view, the synthetical and the analytical ; that is to Bay, the
Sroperties of an element on which the preparation of its compounds epends will he illustrated by descriptions of actual experiments (uBually performed on a small scale), and thus the chemistry of the Fharmacopteia be systematically leanit ; then the reactions by which the element is detected, though combined with other substances, will be performed, and so the student be instructed in qualitative analysis. Synthetical and analytical reactions are, in truth, fre- quently identical, the object with which they are performed giving them synthetical interest on the one hand, or analytical interest on the otier.
A good knowledge of chemistry may be acquired synthetically by manufacturing specimens of the salts of the different metals, or analy- tically by going through a course of pure qualitative analysis. But the former demands a larger expenditure of time than most students have to spare, while under the latter system they generally lose sight of the synthetical interest which attaches to analytical reac- tions. Hence the more useful system, now offered, of studying each metal, &c., ft'om both poiptp pf view, time being economized by omitting the preparatipn ofl^rge specimens of all compounds. 4*
id .y Google
POTASSIUM.
Chemical aynthesis and analysis, thoughtfully and conscientiously followed, will inBensibly carry the principles of chemistry into the mind and fix them there indelibly.
Symbol K. Atomic weight SB.
Memoranda. — The chief sonrces of the potaasinm salts* are the nitrate, found in soils, especially in warm countries, and the com- pounds of potassinro existing in plants. The latter, vegetable salts of potassium, are CJinverted into carbonate with some snlphate, etc., when the wood is burned to ashes. The ashes lixiviated with water, the solution evaporated te drvEesB, and the residue fused, constitute crude potashes. If the residue be calcined on the hearth of a reverberatory fhrnace till white, the product is termed pearlash {Pofassm Oarhonas Impura, U. S. P.). Large quantities of car- bonate are thus produced in North America and Russia; and it is from this salt, purified " by treating the pearlash with its own weight of distilled water, filtering, and evaporating the solution so formed to dryness, while it is liept brisltly agitated" {Potassee Carbonas, B. P., KjCO,, "with about 16 per cent, of crystallization"), that nearly all other compounds of potassium are made. An exception occurs in cream of tartar {Potasses Tartras Acida, B. P. ; Potassce Bitartras, U. S. P.), which is simply the purified natural potassium salt of the grape-vine. Potassium is a constituent of between forty and fifty chemical or Galenical preparations of the British Pbarma- copffliEi.
Carbonate of potassium is a white crystalline or granular powder, insoluble in alcohol, very soluble in water, rapidly liquefying in the air through absorption of moisture, allcaline and caustic to the taste. It loses all water at a red heat PotasBce Carbonas Pura, U. 8. P., is obtained by heating the bicarbonate to redness : the resu' white anhydrous carbonate is converted into hydrous granular bonate by solution in water and evaporation until a dry semi-crys- talline salt remains.
Preparation.< — Potassium itself is isolated with some difficulty by distilling a mixture of its carbonate and charcoal. It rapidly oxidizes in the air, and hence is always kept below the surface of mineral naphtha, a Ijguid containing no oxygen.
Quantivaknce. — The atom of pota^iura Is univalent, K'.
Ebactiohs HAViKO {a) Sykthbtical and (6) Analytical iNrBaEsr. (a) Syntheticai Reactions. These are actions utilized in manufacturing j*eparations of potas- sium. The word synthesis is Itom aivBtaii (sUnthisis), a putting together, as opposed te analysis, from mis,w (analuo), I rraolve.
* The term foU includes any definite solid ohemica! eubatanee, but jnoru aspeoially llioae which assume a crystalline form.
id .y Google
HYDRATE
Hydrate of Potassium.— Caustic Potash.
First Synthetical Meaction. — Boil together, for a few minutes, iii a test-tube, five or six grains of carbonate of potassium (KaCO,) and a like quantity of slaked lime (Ca2H0) with a small quantity of water. Set the mixture aside in the test-tube rack till all solid matter has subsided.
This liqnid is a solution of caustic potash, or hydrate of j)otas- sium (KHO). Made of a prescribed etrength, it forms the Liquor FotasscE, B. P. {5.84 per cent.), and U. S. P. (5.8 per cent).
The mixture is known to be boiled long enough when a little of the clear liquid, poured into another t«at-t«be and warmed, gives no effervescence on the addition of an acid (sulphuric, hydrochloric, or acetic) — a test whose mode of action will be explained hereafter.
Bed metliod of expresumg deeompositions. — This will be easy of comprehension it what has already Been stated concerning symbols and fonnalEe on pages 27 to 36, has been carefully and thoughtfully considered. The beat means of showing on paper the action which ocoure when chemical substances attack each other is by the employ- ment either of equations or diagrams. In an equation the formuhe of the salts used are written on one line, the sign of addition (+) intervening; the sign of equality (=) fallows, and then the formule of the salts produced also separatea hy a plus sign (+). Thus : —
K,00, + Ca2H0 = 2EH0 + OaCO,.
In tliis reaction (the operation just performed) the metals of the two salts change places ; from K^OOj and OaSHO there are pro- duced OaCOj and KHO (two molecules) ; from carbonate of potas- sium and hydrate of calcinra there r^ult carbonate of calcium (the insoluble portion) and hydrate of potassium (in solution).
lii constructing a diagram, or pictorial illuslration of a chemical reaction, firstly, me formulte of the salts used are written nnder each other on the left side of a leaf of a note-book ; secondly, on the right are written the formulas of the sails produced ; thirdly, the paths which may be supposed to be taken by the respective elements are indicated "by the use of brackets and Maes, as follows:—
2KH0
It will be noticed that the only important data required in making either equationary or diagrammatic not«3 of decompositions are the svmboHc formulas of the varions compounds employed or produced. Tliese formulie are, in this manual, given whenever necessary, (Chem-
id.y Google
44 THE METALLIC KADTCALS.
ists obtain them in the flret instance hy the help of qnautitative
Note on Nomendativre. — Hydroies are bodies indirectly or directly derived from wafer by one-half of its hydrogen becoming displaced by an equivalent quantity of another ramca!. Thus, a piece of potassinm throivn on to wafer (HHO) instantly liberates hydrogen, hydrate of pota,Bsiani (KHO) bemg formed, 'fhe temperature pro- duced at the same time is sufficiently high to cause ignition of the hydrogen, which bums with a purple flame (owing to the presence of a little vapor of potassium), while the hydrate of potassium remains dissolved in the bulb of the water.
Explanation. — With regard to the groups of atoms represented by the symbols CO, and HO, only a few words need be said here. The former (CO,) is the grouping (root or radical) found in all car- bonates ; it IS termed the carbonic radical, and ns as characteristie of carbonates as potassium (^) is of potassium salts HO is charac- teristic of all hydrates. 00, is a Divalent grouping or root, HO univalent; hence COj is found united with two equivalent itoms, as in carbonate of potassium, KjOOj, or with one bivalent atom, as in carbonate of calcium, CaCOs ; and HO is fonnd nnited in singl proportion with univalent atoms as in hydrate of potassium EHO or in double proportion with bivalent atoms as in hydrate of calcium, Ca2H0. The quantivalence of a metal .has only to be learnt, and the formula of its carbonate and hydrate are ascertained without seeing the formula of either. The formulte of all other metallic salts are constructed on the same principle. But, beyond committing to memory the formulas and quantivalence of the various groupings characteristic of carbonates, hydrates, nitrates, sulphates, acetates, etc. (see the following Table), special attention should not at present he devoted to the subject of the constitution of salts, but restricted to what may be called the metallic or basylous side of salts. The formnlse and quantivalence of the chief acidulous gronpings referred to and the symbols and quantivalence of allied elementary bodies are included in the following Table ; —
Pormvlm and Quantivalence of Acidulous Radicals. All chlorides contain
iodides
cyanides
hydrates
nitrates
chlorates
cXo.
id .y Google
POTASSIUM. 45
All citrates contain .... OkH^O, ) ^ p. " phosphates " .... POj r a'S
" Watea . " . . . . BO3 ] |-g
Radicals. — The above elements and componndfl are termed radi- cals, each being the common root (radiix) in a series of salts. A compound radical loses its peculiar power when, by superior force, it is broken up into its constituent elements; and an element apparently loses its power as a radical when it is forced to join with other elements in forming a compound i-adioal. Some of the compound radicals are obtainable in the free state, others have yet to be proved capable of isolated exi8t«nce.*
Pure sohition of potash. — Solution of potash generally contains a trace of alumina aisaolved from the lime by the hot alkali, but not enough to interfere with the use of the liquid in medicine. If the solution is required for analytical purposes, it may be obtained free from alumina by avoiding Wie employment of heat, in the manner snggested by Redwood. Half a gallon to made by mixing half a ■pound of slaked lime with about three pints of water, placing the mixture in a half-gallon bottle (Winchester quart), and adding to it, in small quantities at a time, a solution of half a pound of carbonate of potassium dissolved in the other pint of water, snaking the mixture well for several minntes after each addition. The whole is now set on one side till clear ; and then, if a small quantity poured into a test-tube and warmed does not effervesce on the addition of hydro chloric acid, the solution i3 fit for use. If effervescence (carbonic acid gas) occurs, the mixture must be again well shaken. If the lime be good and recently slaked, and the bottle violently shaken once every half-hour, the decomposition will be complete iu about ten or twelve hours.
Liguor Potasste is officially directed to be made as follows : —
Dissolve 1 pound of carbonate of potassium in 1 gallon of water; heat the solution to the boiling-point in a clean iron vessel, gradually mix wiOi it 12 ouacea of slaked lime, and continue the ebullition for ten minutes with constant stirring. Then remove the vessel from the fire ; and when by the subsidence of the insoluble matter the super- natant liquor has become perfectly clear, transfer it hj means of a siphon or by decantation to a green-glass bottle furnished with an ait-tight stopper, and add distilled water, if necKsary, to make it correspond with the teste of specific gravity and neiitraliiing-power. The method of applying these tests will be explained in subsequent
Solid potash. — Solution of potash evaporated to dryness in a silver or clean iron vessel and the residue fused and poured into moulds constitutes Potassa Oaustica, B. P.; Potasm, TJ. S. P. It oft«ii contains chloride and sulphates, detected by nitrate of silver and a barium salt, as described subsequently in connection with hydro- chloric and sulphuric acids. Potassa ciim Galce, JJ. S. P., is a
id .y Google
METALLIC BADICA
Salpliiirated Potash.
Second Synthetical Reaction. — IdIo a test-tiibo put a few grains of carbonate of potasaiQm previously mixed with half ita weight of salphur. Heat the mixture gradually until it ceases to effervesce. The resulting fused mass poured on a slab and quickly bottled is the Potasaa Sulphuroia, Sulphurated Potash, of B. P., or the Potassii Sulphuretum, U. S. P.
This salt is not a definite chemical compound, but a mistnre of several substances, among whioh are sulphate of potassium (K^SO,), and one or more of the sulphides of potassium. In short, the chemical character of this compound is well indicated by its vague name. It is of the color of liver wheo freshly prepared (whence the old name " liver of salphur") ; but from absorption of oxygen it soon changes to green and yellow, and ultimately becomes white and aseless. Becently made, " about three-fonrths of its weight are dissolved by rectified spirit." It is occasionally employed in the form of ointment.
In preparing large quantities of sulphurated potash, the testtube is replaced by an earthenware vessel termed a crucible (from crux, a cross, for originally a cross was impressed upon the meltiug-pot as used by alchemists and goldsmiths ; others derive the word from cmx, an instrument of torture, the sense here being synrtiolical).
Seating crudbks. — Crucibles of a few ounces' capacity may be heated in an ordiuary grate-flre. Larger ones require a stove with a good draught — that is, a/ttmace. Bveu the smaller ones are more convenienwy and quickly heated in a furnace. Half-ounce or one ounce experimental porcelain crucibles maj^ be heated in a spirit- or gas-flame ; the air gas-flame already descnbed being generally the most suitable.
Acetate of Potassium, Third Synthetical Beaction. — Place ten, twenty grains, or more of carbonate of potassium in a small dish, and saturate {satur, full) with acetic acid ; that is, add acetic acid so long as effervescence is thereby produced ; the re- sulting liquid is a strong solution of acetate of potassium. Evaporate most of the water, stirring with a glass rod* to promote the evolution of vapor; a white salt remains which fuses on the further application of heat : this is the
* QlflSH rod is usually purchased in the form of long stioka. The pieces may ha out to poiivenient lengths of from 6 to 12 inclies (fiide p, 16), sharp euds being rounded off by holiiing in a flame for a few Qiiuutes.
id, Google
POTASSIUM. i^
official Acetate of Potash {Potassse Acetas, B. P. and U, S. P.), or Acetate of PotaBsium as it is more correctly called. It forms a white deliquescent foliaceous satiny mass, neutral to test-paper, and wholly soluble in spirit. A ten per cent, solution in water forms the "Solution of Acetate of Potash," B. P.
K:,C0, + SHC^H^O,
Explanation of formtdis. — The formula for acetic acid (the ace- tate of hydrogen) is HO^jO,, and of acetate of potaSBium KO, HjOj. The grouping, 0^,0., is characteristic of all acetates ; it is univalent, and may be shortly, though less instructively, written A.
Explanation of process. — When two molecules of acetic acid (aHCjHjOj) and one of carbonate of potassium (KjOOj) react, two molecules of acetat* of potassium (2KCjHjOj) and one of carbouie acid (H,CO,) are prodn&ed, the latter at once splitting up into water (HjO) and carbonic acid gas (COj), as ali-eadj shown m the equa-
Diagram of the Reaction. — The nature of the above operation is indicated by an equation ; it (and ail succeeding reactions) should be expressed ia the student's note-book as a diagram, similar to that just given in connection with the first S3mthetical reaction. In con- structing a diagram, a little reflection concerning the formahe of the bodies produced will show how the symbols in the formula of the bodies employed are to be arranged on the right-hand side of the brackets.
Evaporation of water from a liquid is best conducted in wide shallow vessels rather than in narrow deep ones, as the steam can thus qniclily diffuse intfl the air arid be rapidly conveyed away ; hence a small roond-bottomed basin is far more suitable than a test- tube for such operations. On the manufacturing scale, iron, or iron lined with enamel or seniiporcelain, copper, tinned copper, or solid tin pans are used. Up to 12 or 18 inches diameter, pans, basins, or dishes, made of Wedgwood ware or porcelain composition, may be employed.
Note. — The above reaction has a general as well as a special syn- thetical interest. It represents one of the commonest methods of forming salts, namely, the saturation of an acid with a carbonate. Carbonates added to acetic acid yield acetates, to nitric acid, ni- trates, to sulphuric acid, sulphates. Many illustrations of this gene- ral process occur in pharmacy.
Eicarhonate of FotEtssinm.
Fourth Synthetical Reaction. — Make a strong solution of carbonate of potassium by heating in a tcst-tabe a mixture of several grains of the salt with rather less than an eq^ual
id .y Google
48 THE METALLIC RADICALS.
weight of water. Through the coolecf solution pass car- bonic acid gas, slowly but continuously; after a time a ■white crystalline precipitate of Acid Carbonate or Bicar- bonate of Potassium (KnCOJ, the Bicarbonate of Potash of the Pharmacopceias (Potassas Bicarhonas, B. P. and TJ. S. P.), will be formed. The more econoiaical official arrangements of the apparatus employed in this process ■will be described nnder the corresponding sodium salt (p. 61).
K,CO, + H,0 + CO, = 2KHC0,
The carbonic acid gas necessary for this operation is to be pre- pared from marhle, though it might be obtained from any carbonate. Thus the previous synthetical reaction could be made available for this purpose, the carbonic gas eToIved on the addition of the acetic acid to the carbonate of potassium being conducted into a strons solution of more carbonate of potassium by a glass tube bent and fitted as described when treatmg of oxygen gas. But motives of economy induce the use of carbonate of cslciam, the form known as marble being always employed. Economy and convenience also cause hydrochloric acid to be used in preference to acetic or any
Oeneraie the carbonic acid gan by adding common hydro- chloric acid, diluted with twice its bulk of water, to a few fragments of marble contained in a test-tube or small flask, and conduct the gas into the solution of carbonate of potassium by a glass tube bent to a convenient angle or angles, and fitted to the test-tube by a cord in the usual way.
Deposition of the bicarbonate eccpte'iiet^.— Bicarbonate of potas- eiuni is to a certain extent soluble in wafer ; but as it is less so than the carbonate of potassium, and as a saturated solution of the latter has been used, the precipitation of a part of the bicarbonate inevi- tably occurs. In other words, the qnantity of water present is snffl- cient to keep the carbonate, but insufficient to retain the equivalent quantity of bicarbonate in solution.
JVf^erties. — Prepared on the large scale, bicarbonate of potassium occurs in colorless, non-deliquescent, right rhombic prisms; it has a saline, feebly alkaline, non-corrosive taste.
Effervescing solution of potash.— A. solution of 30 grains of bi- carbonate of potassium in one pint of water, charged with 1 times its bulk (often less) of carbonic acid gas by pressure, constitutes the ordinary " potasli-wafer," the so called Liquor Potass^ Effervescens, B. P.
Notes on Nom,endaiuTe. — The prefix 6*- in the name " bicarbo- nate of potassium," serves to recall the fact that to a given amount
id .y Google
POTASSIUM, 49
of potaaBiuni ttia salt contains twice as much carbonic radical as the taubonate. The salt is really a " carbonate of potassium and hydrogen" (KHOOs); it is intermediate between carhonate of potas- sium FKiOOj) and carbonate of hydrogen, or trne carbonic acid (HjOO,) ; it is " acid carbonate of potassium" or " hydric potassinm carbonate ;" chemically, though not physically, it is an acid salt.
Salte whose specific names end in the syllable "ate" (carbonate, sulphoie, etc.) are in general conventionally so termed when they contain an acidulous radical, or the characteristic elements of an acid, whose name ends in "ic," and from which acid they have been or may be formed. Thus the syllable " ate" in the words snlpharfe, nitvate, acetaie, carbona(e, etc., indicates that the respective salts contain a radical whose name ended in ie, the previous syllables, sulph-, nitr-, acet-, carbon-, indicating what that radical was — the sul- phuric, nitric, acetic, or carbonic. Occasionally a letter or syllable ia dropped from or added to a word to render the name more eupho- nious ; thus tho sulphuric radical forms sulphates, not sulphurates.
Citrate of Potassitim. Fifth Synthetical JieacitoK.— Dissolve a few grains or more of citric acid (HjCgHjOj) in water, and add carbon- ate (bicarbonate, TJ. S. P.) of potassium until it no longer causes effervescence, and Che solution after well stirring is neutral or faintly acid to test paper. The resulting liquid is a solution of citrate of potassium (KjCgH^Oj) {Liquor Potasses Giiratia, IT. S. P.). Evaporated to dryness, in an open dish, a pulverulent or granular residue is obtained, which is the official Potassee Oitras, B. P. and TJ. S. P., a white deliquescent powder.
3K,C03 + sn^OJtfi, = 2K,CaH,0, + 3H,0 -f 300,
Citrates. — The citric radical or group of elements, which with three atoms of hydrogen forms citric acid, and with three of potas- sium citrate of potassium, is a trivalent grouptnff; hence the three atoms of potassium in a molecule of the citrate. The ftill chemistry of citric acid and other citrates will he subsequently described.
Nitrate of potmsiwn (KNO,) IPotassce Nitras, B. P. and U.S. F.) and SiUphafe of potassiwn (K,80,) (Potasam Sulphas, B. P. and V. 8. P.j could obviously also be made by saturating nitric acid (HNOj), and sulphuric acid (HjSOj), respectively, by cai'bonate of potassium. Practically they are not made in that way — the nitrate occurring, as already sfaited, in nature, and the sulphate as a by-pro- duct in many operations. Both Baits Will be hereafter alluded to in connection with nitric acid.
id .y Google
Tartrate of Potassium.
Sixth Synthetical Eeaetion. — Place a few grains of car- bonate of potassium in a test-tube witli a little water, heat to tlie boiling-point, and then add acid tartrate of potassium (KHC^H^j or KHT) till there is no more effervescence, and the solution is neutral to test-paper ; a solution of neutral tartrate of potassium (,K,T) results, the Fotassm Tartras of the British and United States Pharmacopoiias. Crystals (i- or 6-sided prisms) may be obtained on concen- trating the solution by evaporation and setting the hot liquid aside. Larger quantities are made in the same way, 20 of acid tartrate and 9 of carbonate (with 50 of water) being about the proportions necessary for neutrality.
2KHCH,0, + K^CO, = 2K,C,H,0a + Hfi + 00,
Tartrates. — O.HiO, are the elements ctaracteristic of all tar- trates; tliey form a bivalent groupii^; hence tlie formnla of the hydrogen tartrate, or tartaric a«id, is HjCHjOj ; that of the potaa- Bium tartrate KjOjH.O.; of the intermediate salt, the acid potas- sium tartrate (cream of tartar), KHC,H,Oj. If the acid tartrate of one metal ami the carbonate of another react, a neutral dimetalhc tartrate r^ulte, as seen in Rochelle salt (KNaOjEjOJ.
Acid salts (e. g. KHOjHjOj), that is, salts intermediate in compo- sition between a normal or neutral salt {e. g. TS.^(jMfig) and an acid (e.g. HjOjHjOj) will freqnentiy be met with. All acidulous radi- cals, except those which are univalent, may be concerned in the for- mation of acid salts.
Iodide of Fotassinm. Seventh Synthetical Eeaetion. — To a solution of potash, heated in a test-tube, flask, or evaporating-basin, accord- ing to quantity, add a small quantity of solid iodine. The deep color of the iodine disappears entirely. This is due to the formation of the colorless salts, iodide of potassium (KI) and iodate of potassium (KlOg), which remain dis- solved in the liquid. Continue the addition of iodine so long as its color, after a few minutes' warming and stirring, disappears; when this point is reached, the whole of the potash in the solution of potash has been converted into the salts mentioned,
6KH0 -1- 81, = SKI + EIO, + SH^O
id .y Google
POTASSIUM. 51
Separation of the iodide from the iodate. — Evaporate the above solution to dryness. If both salts were required, the solid mixture might be digested in spirits of wine, which dissolves the iodide, but not the iodate. But the iodide only is used in medicine. Mix the residue, therefore (re- serving a grain or two for a subsequent experiment), with about a twelfth of its weight of charcoal, and gently heat in a test-tube or crucible until slight deflagration ensues.*
2KIO3 -I- 30, = 2KI -h 600
Under these circumstances the iodide remains unafifected, but the iodate loses all its oxygen, and is thus also re- duced to the state of .iodide. Treat the mass with a little water, and filter to separate excess of charcoal; a solution of pare iodide of potassium results. It may be used as a reagent or evaporated to a small bulk, and set aside to crystallize.
This is the process mentioneii in the BritiBh and United States Pharmacopceias {Potassii lodidum). "Solution of Iodate of Potas- sium" is also official as a test-liquid.
J¥opeTttes. — Iodide of potassium crystallizes in small cubical erjstafc, very soluble in water, less so in spirit. One part in ten of water forms "Solution of Iodide of PotaBSium," B. P.
The addition of charcoal in the above process is simply to facili- tate the removal of the oxygen of the iodate of potassium. Iodate of potassium (KIOj) is analogous in constitution, and in compoai- tion, so far as the atoms of oxygen are concerned, to chlorate of po. tassinm (KOlO,), which has already been stated to be more useful than any other salt for the actual preparation of oxygen gas itself. Hence the removal of the oxygen of the iodate might be accom-
!)lished by heating the residue without charcoal. In that case the iberated oxygen would be detected on inserting the incandescent ex- tremity of a strip of wood into the mouth of flie teat-tube in which the mixture of iodide and iodate had been heated. The charcoal, however, bums out the oxygen more quioltly, and thus economizes
* DaBagration means violent bui'nliig, from fiagrnfjis, burnt (Jlagro, I burn), and de, 3, prefix augmeoting the sense of the word to which it may be attached. Paper thrown into a fire simply burns, nitre deflagrates. De-touate idetono) is a precisely similar word, meaning to explode with violent noise.
If, in the operation al beating iodate of potassium with oharcoal, exoess of the latter he employed, slight inoaiideacBnee rather than dBliagratioii ooturs ; it the cliarcoal be largely in exuess, the reduo- tion of tlie iodate to iodide of potaaslum ia effeoted without visible deHagration or even insaiideSDeuce.
id, Google
52 THE METALLIC RADICALS.
Detection of iodate in iodide of potassium. — Todate of potassium remaining as an impurity in iodide of potassium may be detected by adding to a solution of the latter salt some tartaric acid, shaking, and then adding mucilage of starch ; blue " iodide of starch" is formed if a trace of iodate be present, but not otherwise. The tartaric acid liberates iodic acid (HIO,) from the iodate of potassium and hydriodic acid (HI) from the iodide of potassium ; neither acid alone attacks starch, but by reaction on each other the two give rise to free iodine which then forms the blue color. This experiment should be tried on a sample of pure iodide of potassium and on a grain or two of the impure iodide reserved from the previous experiment. HIO, + 5HI = 3H,0 + 31,.
Note on Nomendature. — The syllable ide attached to tlie syllable iod in the name "iodide of potaasiam," indicates that the element iodine is combined with the potassium. An iodaie, as already ex- plained, is a salt containing' the characteristic elements of iodic acid and all iodic compounds, Salts, one of whose names ends in ide, are those which are, or may be, formed from elements. The names of salts which are, or may be, formed from compounds include other syllables, oie being one (see page 49). The only other syllable is tte, which is included in the names of salts which are, or may be, formed from acids and radicals whose names end in ov,s: thus hypo- sulphiie of sodium, &e. To recapitulate : A salt whose name ends in ate contains a componnd acidulous radical whose name ends in 4c; a salt whose name ends in ite contains a compound acidulous radical whose name ends in oua; a salt whose name ends in ide con- tains an element for its acidulous radical. Thus, sulphide relates to sulphur, Bulphiile to the enlphurous radical, sulphate to the sul- phuric radical, and so on with ail other " ides," " ites," or " ates."
Bromide of Potassium {Potassii Bromidum, B, P.). — This salt is identical in constitution with iodide of potassium, and may be made in exactly the same way, bromine being substituted for iodme. The formula of bromie acid is HBrOj. It will be noticed that the follow- ing equations are similar in character to those showing the prepara^ tion of iodide of potassium.
6KH0 + SBr^ = 5KBr + KBrO, + 3H^0
SKBrOg + 3C, = 3KBr + 600
Potassii Bromidum, U. S. P., is made by decomposing solution of bromide of hon (Fel,) by solution of pure carbonate of potassium (KjOO,), evaporating and crystallizing.
id .y Google
53
Iffanganates of Fotassiiuu. Eighth Synthetical Seacfton.— Place a fragment of solid caustic potash (KHO), with about ttie same quantity of chlorate of potassium (KCIOJ, and of black oxide of man- ganese (MnO,), on a piece of platinum foil.* Hold the foil by a small pair of forceps or tongs in the flame of a blowpipe for a few minutes until the fused mixture has become dark green. This color is that of manganate of potassium (K^MnO^).
6KH0 + KCIO, + 3MnO, = 3K,MnO. + KCl + 3H,0
EjHi-aK! ot Chloruleol Blank oxide of Manganatfl o? Chloriiie ot WaMr.
Ninth Synthetical Reaction. — Permanganate of Potas- sium (K^MftgOa) {Potassse Permanganas, B. P. and U. S. P.)i which is purple, is obtained, or rather a solution of it, on placing the foil and its adherent mass in water, and boiling for a short time.
3K,MnO, + 2H,0 = K^Mn^O^ -}- 4KH0 + MnOg
On tlie large scale, the potash set free in the reaction ia neutral- ized by sulpliuric or carbonic acid, and the solution evaporated to the crystallizing point Further details will be given in connection with manganese.
Solutions of manganate or permanganate of potassium so readily yield their oxygen to organic matter, that they are used on the large scale as disinfectaaita, under the name of "Condy's Bisinfecting Fluids." ,
Synthetical Reactions bringing under consideration the remain- ing official compounds (namely, bichromate, areenit*, chlorate, cyan- ide, ferrocyanide, and ferridcyanide of potassium) a" -'—--—=• -^
[h] Reactions having Analj/tioal Interest (Tests). JVbfe. — These are reactions ntilized.in searching for small quanti- ties of a snbstance (in the present instance of potassium) in a solution. They are beet performed in test-tubes or other small vessels. Each should be expressed, in the form of an equation or diagram, in the Btniient's note-book. All previojis or fntwre equaiions given in this
* The foil may be 1 inch broad by 2 long. No ordinary flame will melt, or common chemica! substance attaok platinum ; hence tba same piece may ba used in experiments over and over again. Metala form a fusible alloy with platinum, and pliospborns rapidly attacks it, hence such snbstauoes, as well as mistnrea likely to yield them, should be heatud in a small porcelain crncible. 5*
id .y Google
64 THE METALLIC RADICALS.
volume should ie transferred to the note-booi: in the form of ditt- grams similar to thai given on page 43.
Mrst Analytical Reaction. — To a solution of any salt of potassium (chloride,* for example) add solution of per- chloride of platinum (PtOI,), and stir the mixture with a glass rod; yellow double chloride of platinum and potas- sium (PtC1.2KCl) will be precipitated.f
E!(^lana^ion. — The precipitat* is, practically, insoluble m. water. It is for this reason tliat a verj small quantity of any soluble potas- sium Bait (or, rather, of the potassium in that salt) ia thrown out of solution bj perohloride of platinum.
PrecaiMon. — Only chloride of potassium forms this characteristic compODud ; hence, if the potassium salt in the solution is known not to be a chloride, or if its conipoaition is unknown, a few drops of hydrochloric acid must be added, otherwise some of the perchloride 01 platinum will be utilized for its chlorine only, the platinum being wasted. Thns, if nitrate of potassium (KNO,) be present, a few drops of hydrochloric acid enable the potassium to assume the form of chloride when the perchloride of platinum is added, nitric acid (HNO,) being set free.
Memoranda. — Experiments with such expensive reagents as per- chloride of platinum are economicaliy performed in watch-glasses, drops of the liquids being operated on. When the jirecipitate is long in forming, it ia sometimes of an orange-yellow tint. If iodide of potassium happen to be the potassium salt under examination, some iodide of platinum (Ptij) will also be formed, giving a red color to the solution, and a larger quantity of the preci]>ita7)t (that is, the precipitating agent) be required.
Note on Nomendatv/re. — When distinct molecules of salts unite and form a single crystalline compound, the product is termed a double salt. The double chloride of potassium and platinum is such
Add Tartrate of Potassium.
Second Analytical Meaction. — To a solution of any salt of potassium add some strong solution of tartaric acid (HgCjHjO,,), and shake or well stir the mixture; a white granular precipitate of acid tartrate of potassium (KHCjH.Ofl) will be formed.
Limits of the Test. — Acid tartrate of potassium is soluble in about 180 parts of cold and in 6 parts of boiling water. Hence, in applying the tartaric test for potassium, the solutions must not he hot. Even if
* A few fraRmeiits of carbonate of potassiuna, two or three drops of hydrochlorio acid, and a small quantity of watar, give a solution of cTiloride of potassium at onoe, KaC03-t-2HCl=2KCl-|-H,0-|-C0j,.
\ By precipitation (from prmcipito, to throw down suddenly) is simply meant the formation of particles of solid in a liquid, do matter whether the soUS, the precipi/aie, subsides Or floats.
id .y Google
POTASSIUM. Bo
cold, no precipitate will be obtained if the solutions are very dilute. Thistest, therefore, is of far leas value than the first mentioned. The acid tartrate of potassium is less soluble in diluted alcohol than in water ; so that the addition of spirit of wine renders the reaction Boniewhat more delicate.
Cream of Tartar. — The precipitate is the Bitartraie or Add Tartrate of Potassium, though the official preparation is not formed in the ahove manner; on the contrary, the a<iid is derived from the salt, which occurs natnrally in the jnice of many plants.
Memorandvan. — When the tartaric acid is added fo the salt of potassium, and the acid tartrate formed, the acid whi^e chief elements were previously with the potassium is set free ; and in such acid solu- tions the acid tartrate is somewhat soluble. To prevent loss on this account, acid tartrate of sodium, a salt tolerahly aoluhle in water, lam be used as a test instead of tartaric acid (Plunkett). The somum uniting wiUi the acidulous radical, thus gives a neutral instead of an acid solution. But this advantage is of less importance from the fact that more water is introduced by the saturated solution of acid tartrate of sodium than by a saturated solution of tartaric
Third Analytical Beaclion. — The Jlame-test. Dip the looped end of a platinum wire into a solution containing a potassium salt, and introduce the loop into a spirit-flame, the flame of a mixture of gas and air, a blowpipe flame, or other slightly colored flame, A violet tint will be pro- duced highly characteristic of salts of potas
Fourth Analylical Fact. — Salts of potaf volatile. Place a fragment of carbonate, nitrate, or any 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 freely over the foil, water also if present will escape as steam, and black carbon be set free if the salt happen to be of vegetable origin; but the potassium compound itself will not be vaporized. This is a valuable negative property, as will bo evident when the analytical reactions of ammonium come under notice.
QUESTIONS AND EXEKOISRS,
65. Name the ee. Give the Fotassinm.
67. Distinguish between sjrnthetical and analytical
68. How is the olBcial Zaqitor Potassm prepared?
69. "What is the systematic name of Caustic Potash J
70. State the chemical formula of Caustic Potash.
id .y Google
56 THE METALLIC RADICALS.
71. Construct an equation or diagram expressive of the reaction between carbonate of potassium and slaked lime.
72. Deflnea hydrate.
73. What group of atoms is charafltoristic of all carbonates ?
74. Define the term radical.
75. How is " Sulphurated Potash" made, and of what salts is it a mixture ?
76. What is the formula of the acetic radical— the radical of all acetates ?
77. Di-aw a diagram showing the formation of Acetate of Potas-
78. Give a general process for the conversion of carbonates into other salts.
79. What is the dilference between Carbonate and Bicarbonate of Potassium ? How is the latter prepared ?
80. What is the relation between salts whose specific uames end in the syllable " ate," and acids ending in " ic" 1
81. Draw out diagrams descriptive of the formation of Tartrate of Potassium from the Acid Tartrate,. and Citrate Irom the Car- bonate of Potassium.
82. Distinguish between a normal and an acid salt.
83. How is Iodide of Potassium made ? Illustrate the process by either diagrams or equations.
84. Describe the appearance and chemical properties of iodide of
85. Give a method for the detection of iodate in iodide of potas- sium. Explain the reaction,
86. Has the syllable "tde" any general signification in chemical nomenclature !
87. What is the diflference between sulphides, sulphites, and sul- phates?
88. Mention the chemical relations of Bromide to Iodide of Potas-
89. Describe the formation of Permanganate of Potassium, giving equations or diagrams,
90. How do manganate and permanganate of potassium act as disinfectants }
91. Enumerate the tests for potassium, explaining by diagrams the various reactions which occur.
SODIUH.
Symbol Na. Atomic weight 23.
Memoranda.— Mmt of the sodium salts met with in Pharmacy are directly obtained from carbonate of sodium, which is now manu- factured on an enormous scale from chloride of sodium (common salt, searsalt, or rock-salt), the natural source of the sodiom salts. When pure, salt '{Sodii Chloridn^, B. P. and U. S. P.) occui-s "in small white crystalline grains, or transparent cubic crystals, free from moisture." Besides the direct and indirect use of carbonate of sodiam, or carbonate of Boda,.as it is commonly called in medicine, it
id .y Google
SODIUM. 61
is largelj used for household cleansiag-purposea undei' the name of "soda," and in the manufacture of Boap. Nitrate of sodium also occurs in nature, hat is valuable for its nitric conatitnenis rather than ita sodium. Sodium is a constituent of about forty chemical or Galenical ;proparations of the Pharmacopceias.
Sodium IB prepared by a process similar to that for potassium, but with less difficulty, Ita atom is univalent, Na'.
Reactions having (a) Synthetioai and (b) Analytical Intekest.
(a) Reactions having Synthetical Interest.
Hydrate of Sodium. Caustie Soda.
First Synthetical Reaction. — The formation of solution of hydrate of sodium or caustic soda, NaHO {Liquor Sodee, B. P. and U. S. P.)- This operation resembles that of making solution of potash.
The practical student should reibr to the remarks made concern- ing solution of potash, applying them to solution of soda. He may Serform the corresponding experiments or omit them, as he considers e does or does not clearly comprehend all they are designed to teach.
Pure Solution of Soda, free from any trace of alumina, may be prepared by sliabiiig in a "Winchester quart, once every 20 or 30 minutes for 5 or 6 hours, 14 ozs. of crystals of carbonate of sodium and 8 ozs, of good recently slaked lime. The official Liquor Sodie is made from 28 ounces of crystals of carbonate of sodium, 12 of slaked lime, and 1 gallon of water, under precisely similar ciroum- Btances to those detailed for Liquor Potaeace (p. 45). If the solu- tion be evaporated to dryness, and the residue fused and poured into moulds, sohd hydrate of sodium {Soda Caustica, B. F.) is obtained.
Action of Sodium on Water. — Sodium, like potassium, decom-
fioses water (HHO or HjO) with production of hydrate of sodium NaBO) and hydrogen (H) ; but unless the sodium is confined to one spot by facing it on a small floating piece of filter-pajjer, the action is not sufflciently intense to cause ignition of the escaping hydrogen. When the latter does ignite, it burna with a yellow flame, due to the presence of a little vapor of sodium.
Second Synthetical Eeaction. — The reaction of sniphur and carbonate of sodium at a high temperature resembles that of sniphur and carbonate of potassium; but as the product is not used in medicine, nor otherwise interesting, the experiment may be omitted. It is mentioned here to
id .y Google
58 THE METALLIC RADICALS.
draw attention to tlie close resemblance of tlic potaesinm salts to thbse of sodium.
Acetate of Sodium. Third Synthetical HeacHon.— 'Add the powder or fva.g- menta of carbonate ofsodiura (Na,CO,) to some strong acetic acid in a test-tube or evaporating-basin as long as efFcrvescenceoccurs, and then evaporate some of the water.* Wiien the solution is cold, crystals of acetate of sodium {NaC,H,0,3HjO) (Sod^Acetas, B. P. and "U. S. P.) will be deposited. A ten per cent, solution in distilled water forms the "Solution of Acetate of Soda," B. P.
Na,CO, 4- 2HC,H,0, = SNaC.HjO, + H.,0 + CO,
;Bicatbonate of Sodium. Fourth Synthetical Seaoiion. — The action of carbonic acid (HjCO,), or carbonic acid gas (COJ and water (H^O), on carbonate of sodium (NajCOa). This resembles that of carbonic acid on carbonate of potassium, but is applied in a different manner. The result is bicarbonate of sodium (NaHCOJ (Sod^ Sicarbonas, B. P. and TJ. S. P.).
Na,CO, + H,0 + CO, = 2NaHC0,
Process. — Heat crystals of carbonate of sodium in a por- celain crucible until no more steam escapes. Mix the pro- duct, in a mortar, with two-thirds its weight of crystals, and place the powder in a test-tube or small bottle into which carbonic acid gas may be convej-ed by a tube pass- ing through a cork and terminating at the bottom of the vessel. To generate the carbonic acid gas fill a test-tube having a small hole in the bottom (or a similar piece of glass tubing, of which one end is plugged by a grooved cork) with fragments of marble, insert a cork and delivery- tube, and connect the latter with the similar tube of the vessel containing the carbonate of sodium by a piece of Indiarfubber tubing. Now plunge the tube of mai'ble into a test-glass, or other vessel, containing a mixture of one
id .y Google
SODIUM. 69
part hydrochloric acid and two parts water, and loosen the cork of the carbon ate- of sodium tube until carbonic acid gas, generated in the marble tube, may be considered to flU the whole arrangement; then replace the cork tightly and set the apparatus aside. As the gas is absorbed by the carbonate of sodium, hydrochloric acid rises into the marble tube, 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 (NaHCOj), it will be found to have become damp through the libera- tion of water from the crystallized carbonate (NajCO„j lOHjO). (It would be inconveniently moist, even semi- fluid, if a part of the carbonate had not previously been rendered anhydrous.) To purify the resulting bicarbonate from any carbonate or traces of other salts, add half its bulk of cold distilled water, set aside for about half an hour, shaking occasionally, drain the undissolved portion, and dry it by exposure on filtering paper.
This is the official process for Sodie Bicarbonas, B, P.: that of the U. S. P. is similar. The arrangement of appa- ratus is also that adopted in the Pharmacopceias for Fotasste Bioarbonas, one part of carbonate dissolved in two-and-a-half parts of water beiug subjected to the action of the gas, and not the solid carbonate as in the case of the sodium salt.
A crystal of carbonate of sodium is carbonate of sodium plus water ; on heating it, more or less of the water ia evolved, and anhy- drous carbonate of sodium ia partially or wholly produced {Sodce Carhonas Exsiccata, B. P, and IT. S. P.).
Note on Nomenclature.-— Anhydrous bodies (from a, a, and SSap, udor, i. e. without water) are compounds from which water has been taken, but whose essential chemical properties are unaltered. Salts containing water arehydrows bodies; of these the larger portion are erjstatline, and their water is then termed water of eryntalUzatiort. Noncrystalline hydrous compounds were formerly spoken of as hydraied substances ; hydrates are, however, a distmot class of bodies, salts derived from water by one-half of ite hydrogen becoming displaced by an equivalent quantity of another radical. Anhydrides are compounds from which the elements of water have been removed, their essential chemical (acid) properties being thereby greatly altered. (For illustrations, see Index, "Anhydrides.")
Waier of Crystallization. — The water in crjatallized carbonate
id .y Google
60 THE METALLIC EADICAL8.
of sodium is in the solid condition, and, like ice and other fueihle substances, requires heat for ils liquefaction. Many salts (freeziog- misturee), when dissolved in water, give & very cold solution. This is because thej and their solid water, if they have any, are then converted into liquids which absorh heat from surrounding media. Take away from water some of its heat, the result is ice. Give to ice (at 32<^ FJ more heat than it contains already, the resnlt is water (stil! at 32^ F.). (Heat thus taken int« a substance without increasing its temperature is said to become latent— (lom lattns, hiding ; it is no longer discoverable by the sense of touch or the thermometer. The tenn latent now gives a somewhat incorrect idea, however, of the process ; for our knowledge of the extent and readiness with which one form of force is convertible into another renders highly probable the assumption that heat is-in these cases converted into motion, the latter enabling the particles of a solid to take up the new ^(sitions demanded by their liquid condition.) The only apparent difference between ice and the water in such crystals as carbonate of sodium is that ice is solid water in the free, and water of crystallization solid water in the combined state. The former can onh' exist at and below freezing, the latter at ordinary temperatures. In chemical formula, the symbols representing water are usually separated by a comma from those representing salts. The crystals of aeetate of sodium (of the third reaction) contain wat«r in this loose state of combina- tion— water of crystallization (NaOjH,©,, 3HjO).
"Soda-water." — A solution of bicarbonate of sodium in water charged with carbonic add gas under pressure constitutes the official Liquor Sodw Rff'ervescens, B. P., and, like the "potash-water" of the shops, is a true medicine, an antacid. Ordinary "soda-water," Low- ever, is in many cases simply a solution of carbonic acid gas in water, and would be more appropriately termed " a'erated water" : any me- dicinal effect it may possess is due to the sedative influence of its carbonic acid gas on the coats of the stomach. At common tempera- tures water disolves about its own volume of carbonic acid gas, both being under equal pressure. One pint of the official sodor-water contains 30 grams of bicarbonate of sodium and a pint of carbonic acid gas ; but the solution is under a pressure of seven atmospheres, so that seven pints of the gas at ordinary atm<«pheric pressure are required for the quantity mentioned.
Sohtbility of gases in water. — Whatever the weight and. volume of a gas dissolved by a liquid at ordinary atmospheric pressure, that weight is doubled by double pressure, the two volumes of gas there- by being reduced to one, trebled at treble pressure, the three volumes of gas being reduced t« one, quadrupled at quadruple pressure the four volumes of gas being reduced to one, and so on 1 his is a general law regarding the solubility of gases in liquids under given temperatures. An average bottle of "soda-water" contams about four times the weight of carbonic acid gas which can eiist m it without artificial pr^sure, so that on removing its cork three times its bulk escape, its own bulk remaining dissolved
Bicarbonate of sodium may also be medicinally administorpd in the form of lozenge (Trochisci Sodis BicaibonuHs B P and U. S. P.).
id .y Google
Tartrate of Fotassinm and Sodium. Fifth SyntheHcal ReacHon. — To some hot strong solu- tion of carbonate of sodium in a test-tube or larger vessel add acid tartrate of potassium till no more effervescence occnrs (about tliree parts to four will be required) ; when the solution is cold, crystals of double tartrate of potas- sium and sodium (Soda Tariarata, B. P., Potasste el Sodm Tartras, TJ. S. P.), the old Eochelle Salt, will be deposited. Na,CQ. + SKHC.n.Og = aKNaO.H.Og + H,0 + CO,
GsrSoDule Acii (urti-ate Double tartrate of Water. Cnrbnniii
ofBudluin. of potastium. pola^siuia »ad EadiUm. acid g»B
FORMUL* OP TaHTRMSS.
Tartaric aciiJ HH GjH,0„
Acid tartrate of potassium . . . . KH OjH^O,
Tartrate of potassium and sodium . . KNaO,HjOj
Very close analoej will be noticed in the conetitutioa of these
salts. When the other tartrates come under notice it will be found
they also have a similar constitution. The crystals of the above
double tartrate contain water {KNaO,H,Oj,4HsO),
HypocUorite of Sodium.
Iced Reaction. — Pass chlori
of carbonate of sodium, bleaching and disinfecting liquid, which, when made of prescribed strength (13 ounces of carbonate in 36 of water, charged by thii washed chlorine from 15 Suid ounces of hydrochloric acid and 4 ounces of black oxide of manga- nese), is the Solution of Chlorinated Soda (Liquor Sodee Chlorate) of the British Pharmacopceia. It is said to contain chloride of sodium (NaCl) and hypochlorite of sodium (NaClO), with some undecomposed acid carbonate
MnO, + 4HCI = MnCl, + 2H„0 -1- CI,
Blk. oxide of ajdrnchlorio Chloride of Wster. Chloiioo.
menganeBO. aeld. loaoganese.
Na^CO, + 01, = NaCl,NaC10 + CO,
Liquor Sodoi Ghlorinatm, TJ. S. P,, is made by decomposing solu- tion of carbonate of sodium by solutioQ of chlorinated lime, sp. gr. 1.045.
2Na,00, + Ca01„Ca2010 = 2(NaOl,Na010) + 20aC0,
id .y Google
other Sodium Compounds.
Synthetical Reactions portraying the chemistrj of the remaiDing official compounds (namely, nitrate, aulphate, hyposnlphite, borate, arseniate, and valerianate of Bodium are deferred until the several acidulOQB radicals of those salts have been deseribed. For phosphate of sodium Bee page 83.
The offidai Citro-Tartrate {Sodte Citro4artras Effei-vescens, B. P.), is a mixture of bicarbonate of sodinm (11 parts), citric acid (6), and tartaric acid (8), heated {to 200° or 220°} nntil the particles aggregate to a grannlar condition. When required for medicinal use, a dose of the mixture is placed in water ; escape of carbonic acid gas at once occurs, a^d an effervescing' liquid resultB.
Soda Powders (Pidveres Effervescevttes, U, S. P.) are formed of 30 grains of bicarbonate of sodinm and 25 of tartaric acid, wrapped separately in papers of different color. When mixed with water, t^rate of sodmm resnits, a little bicarbonate also remaining.
In the ntftnufacture of Carbonate of Sodium from chloride, the latter is first conv^ted into sulphate, llie snlphate is then roasted with coal and limestone, and tlie resnlting' blaok-ash liuTiated {lis^ via, from lix, lye — water impregnated with alkaline salts : hence Uxiviation, lie operation of washing a mixtnre with the view of dissolving out salts). The lye, evaporated to dryness, yields crude carbonate of sodiam (soda-ash). This process wilt be further de- scribed in connection with Carbonates.
Deliquescence and Efflorescence. — The carbonates of sodium and potarainm, chemically closely allied, are readily distinguished physi- cally. Carbonate of potassium qnickly absorbs moisture from the air and becomes damp, wet, and finally void — it is ddiguescent [deli- qvsscens, melting away). Carbonate of sodinm, on l£e other hand, yields some of its water of crjslalliEation to the air, the crystals becoming whit«, opaque, and pulverulent — it is ^orescent (effior^ eBcetit, blowingas a flower.
Analogy of Sodmm salts to Potassiitm, sails.— Otha synthetical reactions might be described similar to those given under potassium, and thus citrate, iodide, bromide, iodate, bromate, chlorate, manga- nate, and permanganate of sodinm, and many other salts be formed. But enough has been stated to show how chemically analogous sodium is to potassium. Such analogies will constantly pr^ent themselves. In few departments of knowledge are order and methoci more perceptible; in few is there as much natural law, as much science, as m chemistry.
Substitution of Potassiv/m and Sodium salts/or each other.' — Sodium salts being cheaper than potassium salts, the former may sometimes be economically suhstinted. 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 potaesinm salt will crystallize more readily than its sodium analogue, or that a.
id .y Google
SODIUM. 63
sodinm salt is stahle when the coi responding potasaium salt has a tendency to absoih moisture or one may he raoie soluble than the other, or the two mai have different mediuinii effects For these or similar reascns a potassium hah has come to he u-^ed in medicine or trade, instead of the corresponding Bodium salt and uzi-e versa. Whenever the acidulous porlioo only is to be utilized, the least expensive salt of the class would nearly always he selected.
(6) Reactions having Analytical Interest.
1. The chief analytical reaction for sodium is the fiame- test. When brought into contact with a Same in the maimer described under potassium (page 55), an intensely yellow color is communicated to the flame by any salt of sodium. This ia highly characteristic— indeed, almost too delicate a test ; for if the point of the wire be touched by the fingers, enough salt (which ia contained in the moisture of the hand) adheres to the wire to communiate a very dis- tinct sodium reaction. These statements ahould be experi- mentally verified, the chloride, sulphate, or any other salt of sodium being employed,
2. Precipita'Tit of sodium. — Sodium is the only metal whose com- mon salts are all soluble in water. Hence no ordinary reagent can be added to a solution containing a sodium salt which shall give a precipitate containing the sodium. A neutral or alkaline solution of a sodtnm salt ^jes, however, a, granular pi^cipitate of antimoniate of aodimn (NajH^SbjO,, 6H,0) if well stirred or shaken with a solu- tion of antimomate of potassiwnt {KjHjSh^O,), but the reagent precipitates other metals, and ia liable to decompose and become useless, and hence is seldom employed.
Antimoniate of potassium ia made by adding, gradually, finely powdered metallic antimony to nitratfl of potassium fused in a cruci- ble so long as deflagration continues. The resulting mass' is boiled with a large quantity of water, the solution filtered and preserved in ;i well-stoppered bottle; for the carbonic gas in the air is rapidly absorbed by the solution, antimonio acid being deposited.
3. Sodium aalts, like thoae of potassium, are not volatile. Prove this fact by the means deacribed when treating of the effect of heat on potassium salts (p. 56).
QUESTIONS AND EXERCISES.
92. How is the official solution of soda prepared ? Give a diagram.
93. Explain the action of sodium or potassium on water. What colors do these elements respectively communicate to flame ?
94. Acetate of sodium : give formula, process, and diagram.
id .y Google
64 THE METALLIC RADICALS.
95. Give a, diagram siowing the formation of bicarlionate of sodium,
96. Wh^ ia a mixtm:e of dried and undried carbonate of soditim employed m the preparation of the bicarbonate ?
97. State the difference between anhydrous and crystallized car- bonate of sodium.
98. Define the terms anhydrous, hydrous, hydrate, anhydride.
99. What do you understand by water of crystallizatioii, ?
100. What is the nature of " Soda-water ?"
101. How many volumes of g^s (reckoned as at ordinary atmo- spheric pressure) are contained in any giyeo volume of the British official "Soda-water!"
102. What is the general law regarding the solubility of gases in liquids under pressure !
103. What is the systematic name of Eocholle salt, and how is the salt prepared t
104. What is the relation of Eochelle salt to cream of tartar and tartaric acid ?
105. Give the mode of preparation and composition of solution of chlorinated soda, and express the process by a diagram.
106. How is the granular effervescing Citro-tai'trale of Sodium prepared ?
lOT. Define D(iiquescffn.ce, Efflorescence, and Lixiviation.
108. What is the general relation of potassium salts to those of sodium?
109. How are sodium salts analytically distinguished from those of potassium }
Symbol NHj or Am. Atomic weight 18.
Memoranda. — The elements nitrogen and hydrogen, in the propor- tion of one atom to four (NHj) are those characteristics of all the compounds about to be studied, just as potassium (K) and sodium (Na) are the characteristic elements of the potassium and sodium com- pounds. Ammonium is a univalent nucleus, root, or radical, like potassium or sodium ; and the ammonium compounds closely resemble those of potassium or sodinm. In short, if, for an instant, potassium or sodium be imagined to be compounds, the analogy between these three series of salts is complete. Yet ammonium never having been isolated, its existence remains a matter of assumption.
Sotirce'. — The source of nearly aU the ammoniacal salts met with in commerce is ammonia-gas (NHj) obtained in distilling coals in the manufacture of ordinary illuminating gas. It is donbtfeas derived from the nitrogen of the plants from which the coal has been produced.
Ammonia. — When this gas (NH,) comes into contact with water (H^O), in the process of washing and cooling coal^as, hydrate of ammonium (NH^HO, or AmHO) is believed to be formed, the ocatogne of hydrate of potassium (KHO) or sodium (NaHO). The
id .y Google
AMMONIUM. 65
grounds for this belief are the observed analogy of the well-known ammoniaoaJ salts to those of potassinm and sodium, the similaritj of action of aolation of potash, soda, and ammonia on salts of metals, and the existence of crystals of an analogous sulphur salt (NH^HS). Chloride of Ammonmrn. — The "ammoniacal liquor" of the gas- works is usually neutralized by hydrochloric acid, by which chloride-
nh:,ho+hoi=nh^ci+h,o ;
and from this salt, purified, the others used in pharmacj' are directly OT indirectly made. Chloride of ammonia (Atamomt CMoridum, B. P., AmmonicE Mv/rias, U. 8. P., occurs '' in colorless, inodorous, translucent fibrous masses, tough, and difficult to powder, soluble in water [1 in 10 is the ' Solution of Chloride of Ammonium,' B, P.] and in rectified Bpirits."
SiUphate of Ammoniwrn (NHj)^ SO4, results when " ammoniacal liquor' is neutralized by oil of vitrol. It is largely used as a constituent of artificial manure in England, and when purified by re- crystaUiaation is employed in pharmacy {Am,'moni<B Sid^haB, U. S. P.)
Volcanic Amimonia. — The purest form of ammonia is that met with in volcanic districts, tmd obtained as a by-product in the manufacture of borax ; the crude bora«ic acid as imported contains about 10 per cent, of ammonium salts, chiefly sulphate, and double sulphates of n with magnesium, sodium, and manganese (Howard).
Re.
Amalgam of Ammonium and Mercury, (a) General UeacHon. — To forty or iifty grains of dry mercury in a dry test-tube, add one or two small pieces of Bodium {freed from adhering naphtha by gentle pressure ■with a piece of fllter-paper), and amalgamate by gently ■warming the tube. To this amalgam, when cold, add some fragments of chloride of ammonium and a strong solution of the same salt. The sodium amalgam soon begins to swell and rapidly increase in bulk, probably overflowing 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 chloride of am- monium, white the ammonium is supposed to form an amalgam with the mercury.
Hydrate of Ammonium. Ammonia. (h) Reactions having Synthetical interest. First Synthetical Reaction. — Heat a few grains of sal-am- moniac with about an equal weight of hydrate of calcium
id .y Google
66 THE METALLIC RADIOALS,
(slaked lime) damped witli a little water in a test-tube ammonia gas is givea off, and may be recognized by its well-known odor. It is very aoliible in water. Pass a d&- livery tnbe, fitted to the teat-tube as described for the preparation of oxygen and hydrogen, into a second test- tube, at the bottom of which is a little water; solution of ammonia will be thus formed.
Amtiionia gas is coniposed of odb atoin of nitrogen with three atoms of hydrogen ; its formula is NH,; two volumes of it contain one Yolnme of nitrogen combined with three atoms or volumes of hydrogen. Its constituents hare therefore in combining suffered con- densation to one-half their normal bulk. Its convereion into hydrate of ammonium may be thus shown;—
NH, + H^O = NH.HO or AmHO
Solutions of Ammonia, prepared by this prooeea on a large scale and io suitable apparatas, are met wifli in pharmacy — the one (sp. gr. 0.891) containing 32.5 per cent., the other (sp. gr. 0.959), 10 per cent, by weight of ammonia gas, NHj, or 66.9 and 20.6 of ammonia, NH.HO (Ltquor Ammoniie Fortior and Liquor Ammoniis, B. P. One part, by measure, of the former, and two of water form the la1> ler). On the large scale, bottles are so arranged in a series as to condense all the ammonia evolved daring the operation. Aqua Amm,om<e Foriior, U. S. P., sp, gr. 0.900, contains 26 per cent, 'a gas. Aqua Ammonice, U. 8. P., has a sp. gr. of 0,960.
Acetate of Ammonium.
t Synthetical Reaction. — To acetic acid and water in a test-tub add powdered commercial carbonate (acid carbonate and carbamate) of ammonium until effervescence ceases ; the resulting liquid, made of prescribed strength, is the official solution of Acetate of Ammonium (NH^Cj H,Oj) {Liquor Ammonim Aeetoiis, B. P. and U. S. P.).
(NH,HC0,),;NH,NH,C0, -l- 4HC,H,0, = 4NH,C,II,0,
id .y Google
AMMONIUM. 67
Carbonates of Ammonium.
Commercial cwrbonaie of ammomum is made by heatinjf a mix- ture of chalk ajid sal-aramoniae ; chloride of calcium (OaOlj) is pro- duced, ammonia gaa (NH,) and wat«r (H,0) escape, and the ammo- niaeal carbonate sublimes* in cakes (Ainmonim Garbonas, B. P. and U. 8. P.). This salt, the empirical formula of which m N,H[5 OjOb, is probably a mixture of two molecules of acid carbonate or bicarbonate of ammonium (2NHjHC0,) and oue of a salt termed carbamate of ammonium (NHjNHiOO,). The latter belongs to an important class of salts known ae cai'bamates, but is the only one of interest to the pharmacist. Cold water extracts it from the commer- cial carbonate of ammonium, leaving the acid carbonate of aniTOoniam undissolved, if the amount of liquid used be very small. In water carbamate soon changes into neutral carbonate of ammonium, NH.NH,CO, + HjO = (NB:4),C0j0r AmjOOs; BO that an aqueous solution of commercial carbonate of cont-aina both acid carbonate and neutral carbonate of
If to such a solution. some ordinary' sotntion of ammonia be added, a -,i_»: — .,» -^fitral carbonate of ammwimm is obtained; and tins n reagent alwaja found ou the shelves of the analytical
laboratory.
AmHOOa + AmHO = AmjOO^ -!- H,0. Neutral carbonate of ammonium is the salt formed on adding strong solution of ammonia to the commercial carbonate in preparing a pungent mixtare for toilet smelling-bottles; but it' is unstable, and on continued exposure to air is reduced to a mass of crystals of the acid carbonate or bicarbonate of ammonium. Bicarbonate of am- monium (NH.HCOj) is also produced on pacing carbonic acid gas into an a^queous solation of commercial carbonate.
Sal Volatile (^iritns Amm,omce ATomaticua, B. P. and TJ. S .P.) is a spirituous solution of ammonia (AmHO), neutral carbonate of
n (AmjCOj), and the oils of nutmeg and lemon (and laven- P.). Petid spirit of ammonia {Sptritus AmmonicE F<xti- dus, B, P.) is an alcoholic solution of the volatile oil of assaftetida
mixed with solution of ammonia. "Solution of Carbonate of Am- monia," B. P., is formed by dissolving half an ounce of the salt in ten ounces of water. S^iritiis AtiimioniiE, TJ. S. P., is an alcoholic solution of ammonia.
Citrate, Phosphate, and Benzoate of Ammonium.
Third Synthetical Meaction. — To solution of citric acid (H,C„HjO, or H,Ci) add solution of ammonia (AmHO) until tho liquid is neutral to test-paper; the product is So-
* Sablimat'on (from sahlimis, high). Vaporiiatiou of a solid siib- staitoe by Imat, and its condensatiou on so upper and ooolei' part of tlie vesasl or spparalus in nliluh (he opuiatiuii is pQifoniiHii.
id .y Google
68 THE MBTALLIO RADICALS.
Intion of Citrate of Ammonium (Am^Ci) Liquor Ammonite Citratis, B. P.J-
Phosphate of Ammonium (AmjnPO,) (jimnwiwce Phosphae, B. P.), and B^izoaie of Atwrnonivm (AmO,Hj^Oj) Ammonite Benzoas, B. P.), are also made by adding aolntion of ammonia to pliosptoric acid (H5PO,) and benzoic add (H0,HjO.J respectively, evaporating (keeping the ammonia in slight excess by adoing more of its solution), and setting aside for cr^tals t« form.
EaO„HjO, + 3AmH0 = AmjCsH-O, + BB.fi
H,POi + 2AmH0 = Am^HPO. + 2H,0
HO-H-O, + AmHO = AinO,EsO, -f H„0
Phosphate of ammonium occurs in transparent colorless prisms, soluble in water, insoluble in spirit; benzoate in crystalline plates, soluble in water and iu Bpirit.
Bromide of Ammonium [Ammonii Bromidum, B. P.) will be noticed in connection with Hydrobromic Acid and otier Bromides.
Oxalate of Ammonium.
Fourth Synthetical Reaction. — To a nearly boiling solu- tion of 1 part of oxalic acid in about 8 of water add carbonate of ammonium until the liquid is neutral to test-paper, filter while hot, and set aside for crystals (NH,),C,0., H^O) to form. The mother-liquor is useful aa a reagent in analysis: 1 of the salt in 40 of water consti- tutes " Solution of Oxalate of Ammonia," B. P.
2H,C,0, + N^H.AOa = 2(NHJ,C 0^ + 3C0^ 4- 2H,0
Sulphydrate of Ammonium. Fifth Synthetical Seaction. — Pass sulphuretted hydrogen gas(H5S) through a small quantity of solution of ammonia in a test-tube, untU. a portion of the liquid no longer causes a white precipitate in solution of sulphate of magnesium (Epsom salt) ; the product is solution of sulphydrate (or sulphide) of ammonium (NH^HS), a most valuable chemical reagent, as will presently be apparent.
NH.HO + n,^S = NH.IIS + H^O.
id .y Google
eULPHTJEETTED HYDROGEN. 69
"SoMion of Sulphide of AintniOiiiv/m," B. P., is made ty passing; the gas prepared in Uie apmrcitus described below, into 3 fluidounces of solution of ammonia (Liquor Ammomw) so long aa the gas continues to be absorbed, then adding 2 more onnees of solution of ammonia, and preserving the solution in a well-stoppered green-glass bottle.
Sulphuretted hydrogen ia a compound of noxious odor ; hence the above operation, and many others, described further on, in which this gas is indispen sable, can only be performed in the open air, or iu a fume-cupboard, a chamber so contrived that deleterous gases and vapors shall escape into a chimney in connection with the external air. In the above experiment, the small quantity of gas required cau be made in a test-tube, after the manner of hydrogen itself. To two or thi-ee fragments of sulphide of iron (FeS), add water and then sulphuric acid ; the gas is at once evolved, and may be conducted by a tube into the solution of
FeS + H,SO, = H,S + FeSO..
The iron remains dissolved in the water in the state of sulphate of
Orystais of svlphydfate of aiwrnoniv/tn, (NH^HS) may be obtained on bringing ammonia gas (NIIj) and sulphuretfed hydrogen (Hj8) together at a low temperature. They are soluble in water without decomposition.
Sulphuretted-hydrogen Apparatus. — As no heat is neces- sary in making sulphuretted hydrogen, the test-tube of the foregoing operation may be advantageously replaced by a bottle, especially when larger quantities of the gas are required. In analytical operations, the gas should be purified by passing it through water contained in a second bottle.
The most convenient arrangement for experimental use is prepared as follows ; Two common wide-mouth bottles are selected, the one having a capacity of about half a pint, the other a quarter pint; the former may be called the generating-bottle, the latter the wash-bottle. Pit two corks to the bottles. Through each cork bore two holes by a round file or other instrument, 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 generating- bottle pass a funnel-tube, so that its extremity may nearly reach the bottom of the bottle. Such " funnel-tubes" may be purchased at the usual shops; or, if the student has
id .y Google
10 THE MKTALLIO RADICALS,
access to a table-blowpipe, and the advantage of a tutor to direct his operations, they may be made by himself. To the other hole adapt a piece of tubing, 6 inches long, and bent in. the middle to a right angle. A similar " elbow- tube" is fitted to one of the holes in the cork of the wash- bottle, and another elbow-tnbe, one arm of which is long enough to reach to near the bottom of the wash-bottle, fitted to the otlier hole. Removing the corlts, two or three ounces of water are now poured into each bottle, an ounce or two of sulphide of iron put into the generating- bottle, and the corks replaced. The elbow-tube of the gene rating-bottle is now attached by a short piece of India-rubber tubing to the long-armed elbow-tube of tlie wash-bottle, so that gas coming fVom the generator may pass through the water in the wash-bottle. The delivery- tube of the waeh-bottie is then lengthened by attaching to it, by India-rubber tubing, a straight piece of glass tubing, three or four inches long. The apparatus is now ready for use. Strong sulphuric acid is poured down the funnel-tube in small quantities at a time, until brisk effervescence is established, and more added from time to time as the evolution of gas becomes slow. The gas passes through the tubes into the waah-bottle, where, as it bubbles up through the water, any trace of sulphuric acid, or other matter mechanically carried over, is arrested, and thence flows out at the delivery-tube into any vessel or liquid that may be placed there to receive it. The generator must be occasionally dismounted, and the sulphate of iron washed out.
Liding (latum, mud). If the corks of the above apparatus, are Bound, and tnbe-holes well made, no escape of gas will occur. If rough corlis have been employed, or the holes are not cylindrical, li^iseed-ioeat lute may be rubbed over the defective parts. The lute is prepared by mixing linseed-meal with water to the consistence of stiff paste. A neat appearance may be given to the lute by gently rubbing a well-wetted finger over its surface.
(c) Meaotions having Analytical Interest ( Tests.) First Analytical Meaction. — To a solution of any salt of ammonium (the chloride, for example) in a test-tube add solution of caustic soda (or solution of potash, or a little slaked lime) ; ammonia gas is at once evolved, recognized by its well-known odor.
Nfl.Cl -1- NaHO = Nn, + n,0 -f- NaGl.
id .y Google
sut-phueettbh hydrogen. 11
Though ammonium itself cannot exist in the free state, its eom-
{ouDda are stable. Ammonia is easilj expelled from those compounds y action of the stronger alkalies, canstic potash, soda, or lime. As a matter of esereise, the stndent should here draw out equations in which acetate (NH.OjHjOJ, sulphate (AmjSOJ, nitrate (NH^NO,), or any other ammoniaeal salt not already haying the odor of am- monia, is supposed to be under examination; also representinEtheuae of the other hydrates, potash (KHO) or slaked lime (Oa2HO).
The odor of ammonia gaa is perhaps the best means of recognizing its presence ; but the following tests are also oceasiooally useful. Into the test-tube in which the am- monia gas is evolved insert a glass rod moistened with hydrochloric acid (that is, with the solution of hydro- chloric acid gas, conventionally termed hydrochloric acid, the Acidum Hydrochloricum of the PharmacopEeias) ; white fumes of chloride of ammonium will he produced.
NHg + HCl = NH^Cl. Hold ft piece of moistened red litmus paper in a tube in which ammonia gas is present; .the red color will be changed to blue.
Te&t-papers. — Lritmus (B. PJ is a blue vegetable pigment, pre- pared from various species of Moccella lichen, exceedingly sensitive to lie action of acida, which turn it red. "When thus reddened, alka- lies (potash, soda, and ammonia) and other soluble hydrates readily turn it blue. The stndent should here test for himself the delicacy of this action by experiments with paper soaked in solutions of litmus and dipped into very dilute solutions of acids, a«id salts (KHC,H,Oj e.g.), alkalies, and such neutral salts as nitrate of potassium, sul- pluife of sodium, or chloride of ammonium.
TinctiM-e of Litmus. — 1 ounce of litmus is macerated for two days in 10 fl. ounces of proof spirit, and the soltition poured off from insolu- ble matter.
Bluelitmus^a^ervi unsized white paper steeped in tincture of litmus and dried by esposure to the air. Red lit'mus paper is unsized white paper steeped in tincture of litmus which has been previously reddened by the addition of a very minute quantity of sulphuric acid, and dried by esposure to the air.
S'uj'mertejiaper, similarly prepared from tincture of turmeric (1 of turmeric root or rhizome to 6 of rectified spirit macerated for seven days), is occasionally useful as a test for alkalies, which turn its yellow to brown ; acids do not affect it.
Second Analytical Meadion. — To a few drops of a solu- tion of an ammonium salt add a drop or two of hydrochloric acid and a like small quantity of solution of perchloride of platinum (PtCl,) ; a yellow crystalline precipitate of the double chloride of platinum and ammonium (PtCljaNH^Cl)
id .y Google
72 THE METALLIC RADICALS,
will be produced, similar in appearance to tlie correspond- ing salt of potassium, the remarks concerning 'which (p. 54) are equally applicable to the precipitate under notice.
Third Analytical Reaction To a moderately strong
solution of an ammonium salt add a strong solution of tartaric acid, and shake or well stir the mixtnre ; a white granular precipitate of acid tartrate of ammonium will be formed.
For data from which to draw out an equation representing this action, see the remarks and formulse under the analogoi^ salt of potassium [p. 55).
Fourth Analytical Fact. — Evaporate a few drops of a solution of an ammonium salt to dryness, or place a frag- ment of a salt in the solid state on a piece of platinum foil, and heat in a flame ; the salt is readily volatilized. As already noticed, the salts of potassium and sodium ai-e Jisned under these circumstaocea, a point of difference of which advantage will frequently be taken in analysis. A porcelain crucible may often be advantageously substituted for platinum foU. in experiments on volatilization.
A wire triangle may be used in supporting crucibles. It is made by placing three (5 or 6 inch) pieces of wire m the form of a tiiangie and then twisting each pair of ends together through half the length of the wires, A piece of tobacco-pipe st«m (about 2 inches) is some- timea placed in the centre of each wire before twisting, the transfer- ence of any metallic matter to the sides of the crucible being thus prevented.
Pradtcal Analysis
With regard to tho«o experiments whith ire us f 1 th as means of detecting (he presence of potassium sodium d
than as illustrating the preparation of salts the t d t h Id
proceed to apply them to certain wlutions of any f th It f
potassium sodirnn and ammonium with the view f as t g
which metal is present that is proceed to pr^fical n lys A
* Such solntiODB ara prepare! in educational laboratories by a tutor. They should under other ciroumatanees be mixed by a friend, aa it IS not de'^irable to know previoasly what is oontained in the aubslanoe about to be analTaed
The analysts ot so1iit!ons containing only one salt serves to impress the mm y w th th 1 araoteiistio tests for the various metals and other a,3 a\ iLnd faniliarize the mind with ohemieal principles. Medical a uden s seldom have time to go fnrtber than this. Mora thorongl analyt aland general chemical knowledge is only acquired
id, Google
POTASSIUM, SODIUM, AMMONIUM. 73
little thought will enable him to apply these reactions in the most suitable order and to the best advantage for the contemplated pur-
5086 ; but the following iwrangementB are perhaps as good as can be evised : —
a salt oi? olje os the metals, potassium, sodium, Ammonium.
Add caustic soda to a small portion of the solution to be examined, and warm the mixture in a test-tube ; the odor of ammonia gas at once reveals the presence of an ammonium aalt.
If ammonium be not present, apply the percbloride-of- platinum test; a yellow precipitate proves the presence of potassium.
(It will be observed that potassium can only be detected in the abaeuce of ammonium, salts of the latter radical giving similar precipitates.)
The flame-test is sufficient for the recognition of sodium.
DIBECTIONS FOR APPLYING THE FOBEGOINQ ANALYTICAL EE- ACTIONS to THE ANALYSIS OP AN AQUEOUS SOLUTION OP SALTS OF ONE, T'WO, OB ALL THREE OB THE ALKALI METALS.
Oommence by testing a small portion of the solution for an ammonium salt. If present, make a memorandum to that effect, and then proceed to get rid of the ammoniacal compound to make way for the detection of potassium : advantage is here taken of the volatility of ammonium salts and the fixity of those of potassium and sodium. Evaporate the original solution to dryness in a small basin, transfer the solid residue to a porcelain crucible, and heat the latter to low redness, or until dense white fumes (of ammoniacal salts) cease to escape. This opera- tion should be conducted in a fume-cupboard, to avoid
by working on snoh mixturea of bodies as are met witli in aetnal praotioe, beginning willi aolutiona whioli may contain any or all the members of a gronp. Heuoe in tkia manna!, two Tables of short directions for analyzing are given under each gronp, Pliarmaoentioai students ahould follow the second Table.
id .y Google
?4 TIIE METALLIC RADICALS.
contamination of the air of the apartment. "Wlion the cra- cible is cold, dissolve out the solid residue with a small quantity of Water, and test the solution for potassium by the perchloride-of-platinum test, and for sodium by the flame-test.
If ammonium is proved to bo absent, the original solu- tion may, of course, be at once tested for potassium and sodium.
Flame^esf. — The violet tint imparted to flame by potassium salts maybe seen when masked by the intense — " — "-'— "••" ■•- -"■" — if the flame be observed throirgh a piece i which absorbs the yellow rays of light.
Note on Nontencloiure. — The operations of evaporation and heating to redness, or ignition, are frequently necessary in analysis, and are nsuallj conducted in the above manner. If vegetable or animal matter be also present^ carbon is set free, and ignition is ac- companied by carftontEaiJowy the material is said to cAor. When- all carbonaceous matter is burnt off, the crucible being slightly in- clined and its cover removed to facilitate combustion, and mineral matter, or ash, alone remains, the operation of incineration has been effected.
Note on the Classificatwn of Elements. — The compounds of po- tassium, sodium, and ammonium have many analogies. Their car- bonates, phosphates, and most other salts are soluble in water. The atoms of the radicals themselves are univalent — that is, replace or are replaced by one atom of hydrogen. In fact, they constitute by their similarity in properties a distmct group or family. All the elements thus naturally fall into classes — a fact that should con- stantly be borne in mind, and evidence of which should always be sought. It would be impossible for the memory to retain the details of Siemislry without a system of classification and leading princi- ples. ClaasiflcatioD 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, as far as possible, on the quantivalcncc of the elements, but chiefly on their analytical relations.
QUESTIONS AND BXEECISES.
110. Why arc ammoniacal salts classed with those of potassium and sodium?
111. Mention the sources of the ammonium salts.
112. Describe the appearance and other characters of Chloride of Ammonium.
113. Adduce evidence of the osislence of a
id .y Google
BVBIljM 15
114. How are tte oliiLial Solutions of Ammonia prepared? Give
115. How is the official Solution of Acetate of Ammoninm pre- pared?
116. Wliat IS the composition of commercial Oarhonate of Ammo-
in. DeSne sublimation.
118. What ammoniaoal aalts are contained in Spintus Ammonim Aromaticus ?
119. Give diagrams illustrating the formation of Citrate, Phos- phate, and Benzoate of Ammoninm.
120. Give the formula of Oxalate of Ammonium.
121. Show how hjdrate of ammonium may be conyerted into sul- phydrate.
122. Describe the preparation of Sulphuretted Hydrogen gas.
123. Enumerate and explain the te ' "
124. How is potassium detected in a. solution iu which das been found?
125. Draw diagrams illustrating the action of hydrate of sodium Dn acetate of ammonium ; hydrate of potassium on sulphate of ammo- Qium ! and hydrate of calcium on nitrate of ammoninm.
126. What are the effects of acids and alkalies on litmus and tur-
128. What raeaniags are commonly assigned to the terms evapo- ratton, ianition, carbonization, and incineration?
129. Write a short article descriptive of the analogies of potas- sium, sodium, and ammonium, and their compounds.
BARllTM. CALCIUM, MAGSESIUM.
These three elements have many analogies. Their atoms are bivalent.
BARITTM. Symbol Ba. Atomic weight 137.
The analytical reactions only of this metal are of interest to the general student of pharmacy. The chloride (BaOijl (Chloride of Barium, B. P. and U. S. P., and " Solution of Chloride of Barium," 1 in 10 of water, B. P.) and nitrate (Ba2N0,) are the soluble salts in common use in. analysis ; and these and others are made hy dis- solving the native carbonate (BaOOj), Barytce Oarhonas, U. S. P., the mineral witherite, in acids, or by heating the other common na- tural compound of barium, the sulphate, heavy white or heavy spar (BaSOJ, with coal—
BaSO, + C, = 4C0 + BaS,
id .y Google
1e THE METALLIC KADICALS.
and dissolving the resulting sulphide in acids. "When the nitrate is strongly heated it is decomposed, the oxide of barium or baryta (BaO) remaining. Bai^ta, on being moistened, assimilates the ele- ments of water with great avidity, and yields hydrate of barium (Ba2H0). The latter is lolerablj soluble, giving haryta-water; and from this solution crystals of hydrate of barium are obtained ou evaporation.
Tne operations above described may ail be performed in test-tubes and small porcelain crucibles heated by the gas-flame. Quantities of 1 oa. to 1 lb. require a coke-fiimace.
Peroaside of barium (BaO,) is formed on passing air over heated baryta. By the action of dilute hydrochloric acid it yields solution oi peroxide of hydrogen (HjO^) or oxygenated water.
Quantivalence. — The atom of barium is bivalent, Ba".
EbACTIOKB HAYXNa ANALYTICAL INTEREST (TeSTs).
First Analytical Meaction To the solution of any aolu-
We salt of barium (nitrate or chloride, for exainple) add dilute Sulphuric acid ; a white precipitate 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 most of the supernatant liquid, add strong nitric acid, and boil ; the precipitate is insoluble.
The production of a white precipitate by sulphuric acid, insoluble even in hot nitric acid, is highly characteristic of barium. The name of this precipitate is sulphate of barium; its formula is BaS04.
Antidotes. — In cases of poisoning by solnble barium salts, any sulphates, such as those of magnesium and sodium (Epsom salt, Glauber's salt, alum), would be obvious antidotes.
-Second Analytical Reaction. — To a barium solution add solution of the yellow chromate of potassium (EjCrOJ ; a pale 3'ellow precipitate (BaCrO^) falls. Add acetic acid to a portion of the chromate of barium ; it is insoluble. Add hydrochloric or nitric acid to another portion ; it is soluble.
" Neutral Chrow,ate." — The red chromate (or bichromate) of pot- assium (KjCrOjjCrO,) must not be used in this reaction, or the barium will be only imperfectly precipitated ; for the red salt jjvea rise to the formation of free acid, in which chromate of barium is to some extent soluble : — K,CrO„ CrOj + 2BaCl5 + H^O = 2BaOrO, -+- 2KC1 + 2HC1.
Yellow chromate is obtained on adding carbonate of potassium, in small quantities at a time, to a hot solution of the red chromate until effervescence ceases ; a little more red chromate ia then added to insure decomposition of any slight excess of carbonate of potaa-
KjOrOj, CrOj + K,P0, = 2K,Cr04 + CO,.
id .y Google
For analytical pnrposeB solutioD of a neutral chromate is still more readily prepared by simply adding solution of ammonia to so- lution of red chromate of potassinm, untO the liquid turns yellow, and, after stirring, smells of ammonia.
ie,CrO„ OrO, + 2NH:,H0 = 2ENH,CrO, + H,0.
Other Analytical Reactions. — To a barium solution add a soluble carbonate (carbonate of ammooium (Am^CO,) will generally be rather more useful than others) ; a white
precipitate of carbonate of barium (BaCOg) results. To
more of the solution add an alkaline phosphate or arseoi- ate (phosphate of sodium (NagHPOJ is the most common of these chemically analogous salts, but phosphate of am- monium (Am^HPO,) or arseniate (AmgllAsOJ will subse- quently have the preference) ; white phosphate of barium ■ (BaHPOJ insoluble in pure water, but slightly soluble in aqueous solutions of some salts, or arseniate of barium (BaHAsOJ, both soluble even in acetic and other weak acids, are precipitated.— — ^To another portion add oxa- late of ammonium (Am^C^OJ ; white oxalate of barium (BaC,Oj) is precipitated, soluble in strong acids, and spa- ringly so in acetic acid. The silico-fluoride of barium
(BaSiFj) is insoluble, and falls readily if an equal volume of spirit of wine be added to the solution under examina- tion after the addition of hydrofluo silicic acid (H^SiFg).
ifem.— Good practice will he found in writing out equatioi aeriptive of each of the foregoing reactions.
QUESTIONS AND EXERCISES.
130. What are the quantivalent relations of barium to other radicals?
131. Write down the formula of oxide, hydrate, chloride, nitrate, carbonate, and sulphate of barium; and state how these salts are prepared.
132. Describe the preparation of peroxide of hydrogen.
133. Which of the testa for barium are most characteristic? Give n of the reactions.
a of poisoning by soluble barium
id .y Google
18 THE METALLIC RADICALS
CALCIUM.
Pjmbiil ("a Atomic fleii-ht 40 Oalcium compoTind= form a large proportion of the crust of onr earth. Carbonate of calcium is met with as chalk, marble, lime- stone, ca,le-spftr, &c , the sulphate, as gypsum oi plaster of Paris ("Plaster of Pans, native sujphat* of calcium — OaSO^, 2HjO — de- prived of water by heat"— B P ), and alabaster, the silicate in many minerals, the flnonde of calcium as fluor-spar. The phosphate is also a common mineral. The element itself is only isolated with great difflcalty. The atom of calcium is bivalent, Oa .
Reactions having Syhthetioai. Intekest.
Chloride of Calcium.
First Synthetical Eeaciion. — To some hydro chloiic acid
add carbonate of calcium {chalk, or, the purer form, white
marble, Marmor Album, B. P. and tT. S. P.) (CaCOJ until
effervescence ceases, filter; solution of chloride of calcium
(CaClj), the most common soluble salt of calcium, ia formed.
CaCO, + 2HC1 = CaCL + n,0 -f CO,
Cii-bonato uf HTdrocblorlo CMorideuf "Water. Carbonic
This solution contains carbonic acid, and will give a precipitate of carbonate of calcium on the addition of lime-water. It may be obtained quite neutral by well boiling before filterihg ofF the excess of marble. It is a serviceable test-liqnid in analytical operations,
Solntion of chloride of calcium evaporated to a syrupy consistence readily yields crystals. These are extremely deliquescent. The solution, evaporated to dryness, and the white residue strongly heated, gives solid anhydrous chloride of calcinm in a porous form. - The resulting agglutinated lumps ( Caldi Ghioridum, B. P. and U. S, P. ) are mnii used for drying gases, and for freezing certain liquids from water. The salt is soluble in alcohol. One part in ten of water constitutes " Solution of Chloride of Calcium," B. P. Four parts in five of water forms the "Solntion (saturated) of Chloride of Calcium," B. P.
Marble often contains ferrous carbonate (FeCOj), which in the above process becomes converted intofen-oua chloride, rendering the chloride of calcium impure : —
FeCO, + 2HC1 = FeCl, 4- H,0 + CO,
If absolutely pure chloride of calcium be required, a few drops of the solution should be poured into a test-tube or test-glass, diluted with water, and examined for iron (by afldiiig sulpliytU'ate of ammonium, which gives a black
id .y Google
CALCIUM. 79
precipitate with salts of iron), and, if tiie latter is present, hypochlorite of calcium (in. tlie form of chlorinated lime) and slaked lime be added to the remaining bulli of the liquid, and the whole boiled for a few minutes, whereby iron is precipitated ; on filtering, a pure solution of chloride of calcium is obtained: —
4FeCl, + Ca2C10 -f 4CaH,0, + 2H,0
Permua HjpDchlorlle Hydjale of Walor.
= 2(Pe,6HO) + 5CaCL
Pevrle. CWoride.
l]fdfu.tfi- of caidum.
This is the official process, and may be imitated on the small scale by adding a minute piece of iron to a li'aginent of the marble before dissolving in acid.
Oxide of Calcium (Quick Lime).
Second Synthetical Reaction. — Place a small piece of chalk in a strong grate-flre or furnace and heat until a trial fragment, chipped oif from time to time and cooled, no longer effervesces on the addition of acid ; caustic lime, CaO {Calx, B. P. and V. S. P.), remains.
CaCO, = CaO + CO,
CarbonBto of Oxide of CBchonio
calcium (chalk). caltjuoi (limo), add gas.
Note. — Etymologlcally conaidered, thia action is analytical (am- Jiyu. analuo, J. resolve) and not synthetical {avudtati. sunthtsts, a putting together); but conventionally it is synthetical, and not aa^lytical ; . for in this, the usnal sense, and the sense in which the words are used throughout this book, synthesis is the application of chemical action with the view ot producing something, analysis the application of chemical action with the view of finding out the com- position of a anbstance. In the etymological view of the matter there is scarcely an operation performed either by the analyst or hy the manufacturer but includes both analysis and synthesis.
Ltme-hilns.- — On the large scale the above operation is carried on in what are termed lime-kilns (Kiln, Saxon, ci/ln, from cylene, a furnace).
Hydrate of Calcium (Slaked Lime).
Slaked Lime. — When cold, add to the lime about half its weight of water, and notice the evolution of steam and other evidence of strong action; the product is slaked lime
id .y Google
80 THE METALLIC RADICALS.
or hydrate of calcium (Ca2H0) (Oalcis hydras, E. P.)i with whatever slight natural impurities the lime might contain.
CaO + H.0 = Ca2H0
Lime. Wuter. Hydrate uf calcium
tslRked lime].
Lime-water. — Place the hydrate of calcium in about a hnndred times its weight of water; in a short time a saturated solution, known as lime-water {Liquor Galcis, B. P. and XS. S. P.), results. It contains about 16 grains of hydrate of calcium {Ca3H0), equivalent to about 11 or 12 grains of lime (CaO), in one pint.
StTOTig Solution of Lime. — Slalsed lime is Dmch more soluble in aqueous solution of sngar than in pure water. The Liquor Golds Saccharatus, B. P., is sneli a solution, containing 2 ounces of sugar and 188 a^ina of hydrate of calcium (Ca2H0), equiyalent to 142
f rains of lime (CaO), in 1 pint. It is a more efficient precipitant of jdratea and carbonates than lime-water. The official process is as follows : Mis 1 ounce of lime and 2 of sugar by trituration in a morfar. Transfer the mixture to a bottle containing 1 pint of water, and, having closed this with a eork, shake it occasiontilly for a few hours. Finally separate tlie clear solution with a siphon and keep it in a stoppered bottle.
Carbonate of Calcium.
Tliird Synthetical Reaction,. — To a solution of chloride of calcium add excess of eai'bonate of sodium, or about 6 parts of dry chloride to 13 of carbonate ; a white preci- pitate of carbonate of calcium (Galcis Garbonas Prsecipi- tata, B. P. and U. S. P.), (CaCO,) results. If the solutions of the salts be made hot before admixtnre, and the whole set aside for a short time, the particles aggregate to a greater extent than when cold water is used, and the pro- duct is finely granular or slightly crystalline. The official variety is thus prepared.
CaCl„ + Na^CO, = CaOO, + 2K"aCl
Collect and purify this Precipitated Chalk by pouring the mixture into a paper cone supported by a funnel, and, when the liquid has passed through the filter, pour water over the precipitate three or four times until the whole of the chloride of sodium Is washed away. This operation is termed washing a precipitate. When dry {vide Index, "drying precipitates") the precipitate is fit for use.
id .y Google
CALCIUM. 81
FUt&nng-paf&e or hibttlous-paper {from Jnbo, to drink), is simply good unsized paper made from the best white rags— white blotting- paper, in fact, of nnnsnally good quality. Students' or analysts' filters, on which to collect precipitates, are round pieces of this paper, from three to six inchM m diametej, twice folded, and then opened ont so as to form a hollow cone. Square pieces are rounded by scissors after folding. The cone is supported by a glass or earthenware funnel.
Washtng-hotfle. — Precipitates are best washed by 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 the cori.the one for a glass tube reach- ing to the bottom of the bottle within, and externally bent to & slightJj acute angle, the other for a tube bent to a slightly obtuse angle, the inner arm terminating just within the bottle. The outer arras may be about 3 inches in length. The extremity of the outer arm continuous with the long tube should be preyiously drawn out to a fine capillary opening by holding the original tube, before cut- ting, in a flame, and, when soft, gently pulling the halves away from each other until the heated portion is reduced to the thinness of a knitting-needle. The tube is now cut at the thin part by a file, and the sharp edges rounded off by placing in a flame for a second or two. The outer extremity of the shorter tube should also be made smooth in the flame. The apparatus being put together, and the bottle nearly filled with water, air blown through the short tube by the lungs, forces water out in a fine stream at the capillary orifice.
DecantattQTt. — Precipitates may also be washed by allowing them to settle, pouring off the supernatant liquid, agitating with water, again allowing to settle, and so on. This is washing by decantaiion (de, from, carithus, a brim). If a stream of liquid flowing from a basin or other vessel exhibits any tendency to run down the outer side of the ve^el, it should be guided by a glass rod placed against the point whence the stream emerges.
If the vessel be too large to handle with convenience, the wash- water may be drawn off by a siphon. A. siphon is a tube of glass, metal, gutta percha, or ludiarrubber, bent into the form of a T or D", filled with water, and inverted ; one end immersed in the wash-water, and the other allowed to hang over the side of the vessel : so long as the outer orifice of the instoument is below the level of the liquid in the vessel, so long will that liquid flow from within outwards until the vessel be empty.*
* The aalare of the action of a siphon i» simple. The ooluran of water in the outer limb is longer, and therefore heavier, than the column of similar area in the inner limb. (The length ot the inuur limb must be reckoned frpm the snrtaee of the liquid, the portion be- low the surface playing no part in the operation.) B«ing heavier, it naturally falls by gravitation, the liquid in the sliort«r limb instantly following, beoauae pressed upwards by the air. The air, be it ob- served, exerts a slcailar amount of pressure on the liquid in the outer limb.: jn short, atniospherio pressure causes the retention of liquid in the iustrumeut, while gravitation determines the direction of the ilon'.
id .y Google
Prepared carbonate of calcinra (Greta Pv<^arata, B. P, and U. S. F.) is merely washed chalk [Greta, B. P. and IT. 8. P.) or wliiting, only that in Pharmacy faehiou demands that the chalk be in little conical lumps, abont the size of thimbles, instead of la the larger rolls characteristic of " whiting." Wet whiting pushed, por- tion by portion, through a fannel, and each separately dried, gives the conventional Greta JPrmparaia. Its powder is amorphous.
Testa PrtEparaia, TJ. 8. P., is powdered oyster-shell, similarly treated. It is an inferior kiad of prepared chalk.
Phosphate of Cillciiim.
Fourth Synthetical Eeaction. — Digest bone-ash (bones burnt in an open crucible with free access of air till all animal and carbonaceous matter has been removed — im- pure phosphate of calcium {Os Uatum, B. P.)) with nearly twice its weight of hydrochloric acid (diluted with three or four times its bulk of water) in a test-tub or larger ves- sel ; the phosphate is dissolved.
Ca,2P0, + 4HC1 = CaH,2P0, + SCaCi,
Phuaphale of Hjdroehloiio Aoii plioepiiaie Chloi'ide of
Dilute with water, filter, boil, and when cold add excess of solution of ammonia ; the phosphate of calcium, now pure {Calds Pkosphas^'B. P.; Calais Phosphas Precipitata, TJ. S. P.), is reprecipitated as a light white amorphous powder. After well washing, t!ie precipitate should be dried over a water-hath (vide Index), or at a temperature not exceeding 513°, to prevent undue aggi'egation of the particles.
+ 4H,0
Bone-black, or Animal Charcoal (Garbo Animalis, B. P. and TJ. S. P.), is the residue obtained on subjecting dried bones {Os, TJ. S. P.) to a ted heat without access of air. The operation may be imitated by heating a few fragments of bone in a covered porcelain crucible in a fume-chamber until smoke and vapor cease to be evolved. Purified Ani- mal Charcoal {Carbo Animalis Purificatus, B. P. and D. S. P.) is obtained by digesting animal charcoal (16 parts) in hydrochloric acid (10 parts) and water (20 parts) in awarm place for a day or two, filtering, thoroughly washing, dry- ing over a water-bath, and igniting the product in a closely
id .y Google
CALCIUM. 83
covered crucible. The acid dissolves ont phosphate of calcium, according to the previous reaction, decomposea and dissolves carbouate of calcinm and sulphide of cal- cium, the carbon remaining unaltered.
Wood Charcoal ( Garbo Ligni, B. P. and U. S. P.) is wood similarly ignited without access of air.
Decolorizing power of Animal Charcoal. — Animal char- coal, in small fi-agments, is the material employed in de- colorizing solutions of common brown sugar with the view of producing white lump sugar. Its power and the nearly equal power of an equivalent quantity of the purified va- riety may be demonstrated on solution of litmus or log- wood.
Phosphate of Sodium. — Phosphate of calcium is con- verted into phosphate of sodium (Sodee Phosphas, B, P. and "0. S. P.) (Na,HF0„12H30) as follows : Mix, in a mortar, 3 ounces of ground bone-earth with 1 fluidounce of sul- phuric acid ; set aside for twenty-four hours to promote reaction; mix in about 3 ounces of water, and put in a warm place for two days, a little water being added to make up for that lost by evaporation ; stir in another 3 ounces of water, warm the whole for a short time, filter, and wash the residua] sulphate of calcium on the filter to remove adhering acid phospliate of calcium ; concentrate the filtrate (solution of acid phosphate of calcium) to about 3 ounces, filter again if necessary, add solution of (about 4^ ounces of crystals of) carbonate of sodium to the hot filtrate until a precipitate (phosphate of calcium, Caa2P0,) ceases to form, and the fiuid is faintly alkaline; filter, eva- porate, and set aside to crystallize.
Phosphate of sodium occurs " in transparent colorless rhombic prisms, terminated by four converging planes, efflorescent, tasting like common salt." One part in ten of water constitutes " Solution of Phosphate of Soda," B. P. This is an official as well as the ordinary process. The following equations show the two decompositions which occur during the operations; —
3(CaH,2POJ + 4Na^00, = 4Na,HP0, -f- 4H,0
+ 400, + Ca,3P0,
Caibomo PhoBTiliate
Hosled^y Google
THE METALLIC RADICALS
Hypochlorite of Calcium.
' Fifth. Synthetical HeacHon — Pass chlorine, generated as already described, into damp slaked line contained in a piece of wide tubing, open at the opposite end to that in which the delivery-tube is iixed. (A test-tube, the bottom of which has been accidentally broken, is very convenient for such operations.) The product is ordinary bleaching- powder, said to be a mixture of hypochlorite and chloride of calcium, commonly called chloride of lime, Calx chlo- rata, B. P. ( Galx Ohlorinata, XS. 8. P.)
MnO, + 4HC1 = MnCl, + 2H,0 + CI, " 2c1h,0, + 201, = 2H,0 -f CaCI,0, , CaCl,
HTirBfoof Chioiine. Waler, HypocLloiIto Clilorfde
<4jclum. otc&Jcium. ofcBlcinm.
Chlorinated lime, exposecl to air and moisture, as in disinfecting' the air of sict rooma, slowly yields hypochlorous acid (HOIOJ. Free hypodilorous acid soon breafcs uj into water, chloric acid (HOIOb), and free dilorine. Ohloric acid is also unstable, decomposing into oxygen, water, chlorine, and perchloric add (HOIOJ. The small
aiantity of hypochlorons acid diffused through an apartment when eaching-powder is exposed thus, yields fourteen-nfteentlis of its chlorine in the form of chlorine gas — one of the most efficient of known disinfectants.
Ble aching-liquor. — Digest chlorinated lime in water, in ■which the bleaching compound is soluble, filter from the undissolved lime, and test the bJe aching-powers of the clear liquid by adding a few drops to a decoction of log- wood slightly acidulated. One pound of this bleaching- powder, shaken several times diiring three hours, with 1 gallon of water, forms Solution of Chlorinated Lime {Liquor Galcis Chloratse, B. P.).
Gummate of Calcium. Gummoie of Calcium is the only official calcium salt that remains to be noticed. This compound is, in short, arabin, the ordinary Gum-Acacia or G-um-Arabio (Acacise Gummi, B. P. and XT. S. P.), a substance too well known to need description, A solution of gum-arabic in water (Mucilago Acacise, B. P. and U. S. P.) yields a white pre- cipitate of oxalate of calcium on the addition of solution of oxalate of ammonium. Or a piece of gum burnt to an ash in a porcelain crucible yields a calcareous residue.
id .y Google
OALOIUM. 85
whicb, dissolved in dilute acids, affords c liar acteris tic re- actions with any of the followiug analytical reagents for calcium. The gummic radical may be precipitated as opaque gelatinous gummate of lead by the addition of solution of oxyacetate of lead (Liquor Plumbi Subacelalis, B. P.) to an aqueous solution of gum. These statements may be experimentally verified by the practical student.
Tragacanth {Tragacantha, B. P. and TJ. S. P.) is usually con- sidered to be ft mixture of soluble gum or arahin and a yariety of calcium gum insoluble in water, termed bassorin : Guibourt thought it to be gclatinoid. With water a gelatinous mucilage is formed (Mucilago Tragaoanthm, B. P. and U. S. P.).
Reactions having Analytical Intekest (Tests).
Fint Analytical Meaction. — Add sulphuric acid, highly diluted, to a calciam solution contained in a test-tube or small tost-glass; sulphate of calcium (CaSO,, 2M.fi) is formed, but is not precipitated, it being, unlike sulphate of barium, slightly soluble in water.
Solution of Sulpliate of Calciwm,. — A quarter of an ounce of that (diTed) form ofsulphate of calcium known as plaster of Paris (CaSO,) digested in one pint of water for a short time, with occasional shak- ing, and the mixture filtered, yields the official test-liquid termed " Solution of Sulphate of Lime," B. P. About 400 parts of the solu- tion contain 1 of sulphate of calcium.
Second Analytical Reaction. — Add yellow chromate of potassium (KjCrOJ to a calcium solution slightly acidified with acetic acid; chromate of calcium (CaOrOJ is pro- bably formed, but ia not precipitated.
Tlvese two negative reactions are most valuable in analysis, as every precipitant of calcium ia also a precipitant of barium ; but the above two reagents are precipitants of barium only. Hence calcium, which when alone can be readily detected by the following reactions, cannot by any reaction be detected in the presence of barium. But by the sulphuric or chromic test barium ia " easily removed, and then either of the following reagenta will throw down the calcium.
Other Analytical Reactions. — Add carbonate of ammo- nium, phosphate of sodium, arseniate of ammonium, and oxalate of ammonium to calcium solutions as described under the analytical reactions of barium, and write out descriptive equations. The' precipitates correspond in appearance to those of barium; their constitution is also identical, hence their correct formulae can easily be de-
id .y Google
86 THE METALLIC EADICALS.
dnced. Of these pvecipitants oxalate of ammonium is that most eoinmoiily used as a reagent for calcium salts, barium lieing absent. The oxalate of calcium is insoluble in acetic, but soluble in hydrochloric or nitric acids.— — Calcium compounds impart a reddish color to flaroe.
QUESTIONS AND EXERCISES.
135. Enumerate some of the common natural compounds of ca!-
136. Explain, by an equation, the action of hydrochloric acid on marhle. what official compounds result?
137. Why is chloride of calcium used as a desiccator for gaaes 1
138. How would you purify Chloride of Calcium which has been made from ferruginous marhle? Give diagrams.
139. Write a few lines on the chemistry of the lime-tiln.
140. In what sense is tie conversion of chalk into lime an analy- tical action ?
141. What occurs when lime is slahed?
142. To what extent is lime soluble in water? to what in syrup?
143. Describe the preparation of the official Precipitated Carbo- nate of Calcium; in what does it differ, from Prepared Chalk?
144. In what does filf«ring-paper differ from otaec kiuda of paper ?
145. Explain the construction of "a washing-bottle" for cleansing precipitates by water.
146. Define decantation.
147. Describe the construction and manner of employment of a
148. Explain the mode of action of a siphon.
149. What is the differonce between Bone, Bone-earth, and Pre- cipitated Phosphate of Calcium ?
150. How is " Bone-earth" purified for use in medicine ?
151. Explain the action of nydrochlorio acid on Animal Charcoal in the conversion of Carbo AniTnalis into Garbo Ammalia Parifi- caius.
152. What is the chemical difference between Carbo Animolis and Garbo Ldgnif
153. Give equations showing the conversion of Ph<»phate of Cal- cium mto Phosphate of Sodium.
164. Write a short article on the manufacture, composition, and uses of " bleaching-powder."
155. How may calcium be detected in Gum-Arabic ?
156. State the chemical nature of Trag-acanth.
157. To what extent is sulphate of calcium soluble in water?
158. Can calcium be precipitated from an aqueous solution con- taining barium ?
159. Barium being absent, what reagents may be used for the de- tection of calcium ? Which is the chief test ?
id .y Google
MAGNESIUM.
Symbol Mg. Atomic weight 24.
Source. — Magnesium is abundant in nature in tlie form f g sian or mountain limestone, or dolomite, a double carbonate of mag neBium and caloinm in common use as a bnildin^nstone (e g the Houses of Parliament, and the School of Mines in London) and magnesile, a, tolerably pure carbonate of magnesium, tl ough too "stony" for direct use in medicine, even if very finely povdeied Ohloride of magnesium and sulphate of magnesium (Epsom salt) also occur in sea-ivater and the water of manv springs. Metallic magne- sium may be obtained from the Chloride by the action of sodium. It burns readily in the air, emitting a dazzling light due to the white heat to which the resulting particles of magnesia (MgO) are ex- posed.
Quanttvaience. — The atom of magnesium is bivalent, Mg".
Reactions having Stntuetical Ixtekest. Sulphate of Magnesium. Mrsi Syntkelical Reaction. — To a few drops of sulphuric acid and a little water in a testrtube (or to larger qnanti- tiea in larger vessels), add carbonate of magnesium (pre- ferably the native carbonate magnesite, MgCO„) until effer- vescence ceases, subsequently boiling to aid in the expul- siori of the carbonic aeid gas. The filtered liquid is a so- lutiou of sulphate of magnesium (MgSOJ, crystals of which, Epsom salt (MgSOj, TH^O) {Magnesiie Sulphas, B. P. and "U. S. P.), may be obtained on evaporating most of the water, and setting the concentrated solution aside to cool. This is an ordinary manufacturing process. Instead of magnesite, dolomite, the common magnesian limestone (CaCOj, MgCOj) may be employed, any iron being removed by evaporating the solution (filtered from the sulphate of calcium produced) to dryness, gently igniting to decom- pose sulphate of iron, dissolving in water, filtering from oxide of iron, and crystallizing.
Sulphate of magnesium readily crystallizes in large, c transparent, rhombic prisms; but, from concentrated solutions, the crystals are deposited iu short thin needles, a form more coaveiiient for manipulation, solution, and general use in medicine.
Iron may be detected in sulphate of magnesium by adding the common alkaline solution of chlorinated lime or chlorinated soda to an aqueous solution of the salt; brovvn hydrate of iron (Pe^6llO) being precipitated.
id .y Google
of
Second Synthetical Reaction. — To solution of sulphate of magoesium add solution of carbonate of sodium and boil ; the resulting precipitate is light carbonate of mag- nesium (Magnesite Carbonas Levis,B.'P.),& white, partly amorphous, partly minutely crystalline mixture of carbonate and hydrate of magnesium (3MgC0„ Mg2H0, 4H,0). A denser, slightly granular precipitate of similar chemical composition {Magnesim Carbonas, B. P. and U. 8. P.) is obtained on mixing strong solutions of the above salts, evaporating to dryness, then removing the sulphate of sodium by digesting the residue in hot water, filtering, washing, and drying the precipitate.
= 3MgC0„ Mg2H0
The official proportions for the light carbonate are 10 of sulphate of magnesium and 12 of cryatala of carbonate of aodium, each dis- solved in 80 of eo!d waier, the solutions mixed, boiled for 15 minutes, the precipitate collected on a filter, well washed, drained, and dried over a water-bath. The heavier carbonate is made with the same proportions of salts, each dissolved in 20 instead of 80 of water, the mixture evaporated guite to dryaeaa, and the reMdne washed by decaotation or filtration until all sulphate of sodium is removed (shown by a white precipitate— sulphate of barium— ceasing to form on the addition of solution of chloriae or nitrate of barium to a little of the filtrate).
Third Synlhelical BeacHott. — Pass carbonic acid gas, generated as described on page 48, into a mixture of water and carbonate of magnesium contained in a test-tube. After some time, separate undissolved carbonate by filtra- tion ; the filtrate contains carbonate of magnesium dissolved by carbonic acid. When of a strength of about 13 grains in one ounce, the solution constitutes " Fluid Magnesia" (Liquor Magnesiie Oarbonatis, B. P.),
Officially, 1 pint is directed to be made from frcshJj prepared car- bonate. The latter is obtained by adding a hot solution of 2 ounces of snlphate of magnesium in half a pint of water to one of 2^ ounces of crystals of carbonate of sodinm in another half pint of water, boiling the mixtare for a short time (to complete decomposition), filtering, thoroughly washing the precipitate, placing the latter in 1 pint of distilled water, and transmitting carbonic acid gas throagh the liquid (say, at the rate of three or four bubbles per second) for
id .y Google
MAGNEK7UM. 89
an hour or two, then leaving the solution in contact with the gas under slight pressure for twenty-four hours, and, finally, filtering from undissolved carbonate, and, aft«r passing in a little more gas, keeping in a well-corked bottle. Slight pressure is best created by placing the earbonaf* and water in a bottle fitted with a coi-h and tubes as for a wash-bottle (p. 69 or 81), conveying the gas by a tube which reaches to the bottom, and allowing excess of gas to flow out by the upper tube, the external end of which is continued to the bottom of a common phial containing about an inch of mercury. The phial should be loosely plugged with cotton wool, to prevent loss of metal by spurting during the flow of the gas through it. (Bach inch in depth of mercury through which the gas escapes corre- sponds to about nalf-a-pound pressure on every square inch of surface within the apparatus.)
Heat a portion of the solution ; true carbonate of magneaium con- taining combined water (MgOOj, SH^O) is precipitated. The water iu this compound is probably in the state of water of crystallization, for a salt having the same composition is deposited in crystals by the spontaneous evaporation of the solution of carbonate of magiie- sinm. The official " carbonate" (3MgOO,. Mg2H0, iUfi) is another of these very common hydrous compomids.
Exposed to cold, the solution of " fluid magnesia" someliines affords large thick crystals (MgOOj, 5H5O), which, in contact with the air, lose water, become opaque, and then have the composition of those deposited by evaporation (MgOO,, 3HjO).
Oxide of Uagnesiiun dSagnesia). Fourth Synthetical Reaction. — Heat some of the above light dry carbonate in a porcelain crucible over a lamp (or in a larger earthen crucible in a furnace) till it ceases to effervesce on adding, to a small portion, water and acid; the residue is light magnesia (MgO) {Magnesia Levis, B. P.). The same operation on the heavy carbonate yields heavy magnesia (MgO) {Magnesia, B. P.). Both are sometimes spoken of as "calcined magnesia" (Jfa^nesin, U. 8. P.). A given weight of the official light magnesia occupies three and a half times the bulk of the weight of heavy n
3MgCO„Mg2HO = 4MgO +
A trace only of magnesia is dissolved by pure water. Moisten a grain or two of magnesia with water, and place the paste on a piece of red litra sis-paper ; the wet spot, after a time, becomea blue, showing that the magnesia ia slightly soluble.
8*
id .y Google
90 THE METALLIC RADICALS.
Keactions having Analytical iNTEREar (Tests).
First Analytical Reaction. — Add solution of hydi'ste or carbonate of ammoDium to a magnesiaii solution (snlphate for example) and boil the mixture in a test-tube ; the pre- cipitation of part only of the magnesium as hydrate (Mg2H0) or carbonate {MgCOJ occurs. Add now to a small portion of the mixture of precipitate and liquid a considerable access of solution of chloride of ammonium ; the precipitate is dissolved.
This is an important reaction, especially as regards carlionate of magnesium, the presence of chloride of ammonium enabling the ftUEdyBt to throw ont from a Bolntion barium and calcium by an alka- line carbonate, magnesium being retained. The cause of this reac- tion is the tendency of magnesium to form soluble double salts with potassium, sodium, or ammonium. In analysis, the chloride of am- monium should be added before the carbonate, as it is easier to pre- vent precipitation than to redissolve a precipitate once formed.
Second Analytical Beaction. — To some of the solution resulting from the last reaction, add solution of phosphate of sodium or ammonium; phosphate of magnesium and
ammonium (MgNH^PO,) is precipitated. 3d To another
portion add arseniate of ammonium ; arseniate of magne- sium and ammonium (MgISfH,AsOJ ia precipitated.
Note. — Barium and calcium are also precipitated by alkaline phos- phates and ai'seniates. The other preoipitants of magnesium are also precipitanta of barium and calcinm. In other words, there is no direct test for magnesium. Hence the analyst always removes any barium or calcinm by an alkaline carbonate, as above indicated ; the phosphate of sodium or arseniate, or phosphate of ammonium, then become very delicate tests of the presence of magnesium. In sneak- ing of magnesium tests, the absence of barium and calcium salts is to be understood.
QUESTIONS AND EXERCISES.
160. Name the natural BOnrces of the various salts of mag
161. Give aprocesafor the preparation of Epsom salt.
162. Draw diagrams illustrative of ttie formation of snl] magnesinm from ^agneaite and from dolorndte.
163. Show by an equation the process for Ihe prepwfttioi official Carbonate of Magnesium.
164. What circiimatancee determine the two different s
id .y Google
MAGNESIUM.
91
165. WliEit are the relations of Magnesia and Magnesia Levis to the oflicial Oai'boaates of Magnesium ?
166. How much denser is the one than the other? 1G7, Ib magnesia solnble in water?
168. How is "Fluid Magnesia" prepared ?
169. Mention the effects of heat and cold on " Flnid MagTiesia." no. Can magnesium he detected in presence of barium and cal-
171. Describe the analysis of an aqueons liquid containing salts of hariiim, calcinm, and magneainm.
172. How may magnesium.be precipitated from solutions con- taining amiiioniacal salts?
Quantivalenee.
On reviewing the foregoing statements regarding compounds of the three univalent radiciJs, potassinm, sodium, and ammonium, and the three bivalent elements, barium, calcium, and magnesium, the doctrine of quantivalence will be more clearly understood, and its usefulnesa more apparent. Qiiantivalence, or the value of atJDms, is, in short, in chemiab^, closely allied to value in commercial barter. A. number of articJes, difTering much in weight, appearance, and general characters, may be of equal money value; and-if these be regarded, for convenience, as having a sort of unit of value, others worth double as much might he termed bivalent, three times as much trfvalent, and so on. In like manner, chemical radieaJs, no matter whether elementary, like potassium (K), iodine (I), or sul- phur (8), or compound, like those of nitrates (NOj), sulphates (SO,), or acetates (OJHjOj), have a given chemical power or value in rela- tion to each other, and are exchangeable for, or will unite with each other to an extent exactly determined by that value.
Most chemical Baits apparently, though probably not really, have two parts, a basylous and an acidulous, the one qnantivalently bal- ancing the other. The formnhe of the chief of these radicals and their quantivalence are given below. Examples of formulte of salts containing univalent, bivalent, aud trivalent radicals are appended.
Quantivalence op Common Raticais.
|
Bivalent Eadicals, |
Trivalent Radicals, |
|||
|
or Monads. |
or Dyads. |
or Triads. |
||
|
A-d 1 |
V"- |
Aoidalouf. |
Enajlong. |
Acidulous. Bns;lou3. |
|
H |
0 |
PO, As |
||
|
01 |
K |
SO, |
Mg |
BO, Sb |
|
I |
Na |
O.H.Os |
Zn |
CjH.O, Bi |
|
HO |
NH, |
Cu |
AsO, ( Fe'Hic) |
|
|
NO, |
Ag |
Hg(ic) |
Aso! \ or |
|
|
C^HjO, |
Ilg(ous) |
s |
Fe(U.) |
C,H,0, (Fe'^Vic) |
id, Google
93 THE METALLIC EAPIOALS.
Note. — The hydrogen (H) in the baaylous jjarts of Baits has en- tirely different functions to the hydrogen (H) in the acidulons part. The latter gives compouDds commonly termed hydrides (e. g. Onll,,) ; in the former the element is the basylona radical of acids (e. o. HOI, H,SOJ.
In compound radicals, e. g. CjHjO, or NH4, the properties of hy- drogen are no longer apparent : the chemical force resident with the atoms of such radicals seems to be mainly exerted in binding those atoms together, tlie excess only of the total amonnt of force giTing the radical univalent, bivalent; or trivalent character. Thns in cai'- bonate of potassium, KjCOj, the. grouping CO, has two units of affinity in excess of those necessaCy for binding together the atoms (C=iv, Ojssvi); the four of the carbon nniting with four of the six of the oxygen leaves two free, and it is this excess which possibly gives the radical its bivalent character. On adding np the nnits.of affinity, or the numbers expressing the qaantivalence of each of the atoms of the radical OjHjO,, or any of the univalent or trivalent radicals of which a Table has just been given, it will be found that an odd number is arrived at; such groupings may be expected to exhibit uneven qu an ti valence.
(E=any hasjlous Eadical.) (J?==any acidulous Radical.) E'Jt'. KI, NaOl, NH.O-HjO,, ji.gNO,. E"ii' . OaOL, Zn2C,HjO„ Pb2N0. {BaNO.C.H.O,). WE',. BiaNO,. AbH„ SbOl,. n\R". \ ( K,CO„ NftjSO., H.C.H,0,. R'R'R". I 1 KHCO,, NaHSO,, KH03,0„. n'.R'". \ ( Am,PO,, K,0,H,0,. H.AsO,. W,WR'". \ 1 Na,EFO,, Na-HAsO,. -B/^B". OaOO,, MgO, cfnSO,, HgO, FeSO,. ^'\R"\. 0a,2P0j, Oa,20„H50-. n"S.'R". MgAmPO., CuHAsO,. W"R"R. BiONO,. I WR": BiC,H,0,. B"'rfi"ifl". BijO,00,. W\R-.. Fe,Ol„,Fe,6NO3,Fe,60.H,O5. R"\R'-s. ASjOj, SbjOj. I ^"'.R',. Vefi,, Fe,3S0j.
EXERCISE.
113. Write an exposition of the doctrine of Qii.ai eiice witiiin the liiuits of a sheet of note paper.
id .y Google
BARIUM, CALCIUM, MAGNESIUM. 93
DIRECTIONS FOR Al'PLYINQ THE FOREGOING ANALYTICAL RE- ACTIONS TO THE ANALYSIS OP AN AQUEOUS SOLUTION OF A SALT OP ONE OF THE METALS, BaRIUM, CaLCIUM, MaG- NEBIUM.
Add yellow ebromate of potassium to a portion of the solntioti to be examined; a precipitate indicates bariam.
If no barium is present, add chloride and carbonate of ammonium, aiid boil ; a precipitate indicates calcium.
If barium and calcium are proved to be absent, add chlo- ride of ammonium, ammonia, and then either phosphate of sodium or arseniate of amrooniam; a white granular pre- cipitate indicates magnesium.
Ammonia a here added to yield tlie necessary elements to ammo- nio-magneaiaTi phosphate or ammonio-m agues iau aifseniate, both of which are highly characteristic precipitates; and chloride of ammo- nlnm is added to preyent a mere partial precipitate of the magne-
DIRECTIONS FOR APPLYING THE FOREGOING ANALYTICAL RE- ACTIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION OP OUE, TWO, OH ALL THEEE OP THE METALS, BaRIUM,
Calcium, Magnesium.
Add chromate of potassium to the solution; barium, if present, is precipitated. Filter, if necessary, and add to the fiUrate (that is, the liquid which has run through the filter) chloride, hydrate, and carbonate of ammonium, and boil; calcium, if present, is precipitated. Filter, if requi- site, and add phosphate of sodium; magnesium, if present, is precipitated.
Note. — Red chromate of potassium must not be used in these ope- rations, or a portion of the barium will remain in the liquid and be thrown domu with, or in the place of, the carbonate of calcium (vide p. 7G). The yellow chromate must not contain carbonate of potas- sium, or calcium will be precipitated with, or in the place of, barium. The absence of carbonate is proved by the non-occurrence of effer- vescence on the addition of hydrochloric acid to a little of the solu- tion of the chromate, previously made hot in a test-tube. If the yellow chromate has been prepared by adding excess of ammonia to solution of red chromate of potassium, its addition to the liquid to be analyzed must be preceded by that of solution of chloride of am- ; the precipitation of a portion of the magnesium (by the
'a m the yellow chromate) ia thus prevented, for chloride-
n solution is a good solvent of hydrate (and carbonate) of magneaiuni.
id, Google
THE MBTAtL
RADICALS,
TAQLE OP anOBT BIKECTIONS FOR APPLYING THE POREOOING ANALYTICAL REACTIONS TO THE ANALYSIS OS AN AQUBOTJS SOLUTION OF SALTS CONTAINING ANI OH AIiL OE THE ME- TALLIO ELEMENTS HITHERTO C0N8IDBRBD.
To the solution add AraOl, AmHO, AmgOOa; boil and filter.
Precipitate
BaOa.
Wasli, dissolve in HC,,H„0,,
add KjCrO^ and filter.
FiltratR
Mg Am Na K.
Add Am3P0 ,, shalie, filter.
n,(-!,d,.
Precipitate Mg.
Filtrate AmNaK. Evap. to dryness, ignite, dissolve residue in water. Test for K by Ft 01^. Test for Na bj flame. Test orig. sol. for Am.
Note 1.— The analysis of solutions containing the foregoing metals is commenced by the addition of chloride of ammonium (AmOl) and ammonia (AmHO), simply as a precautionary measure, the former compound preventing partial precipitation of magnesium, the latter neutt'alizing acids. The carbonate of ammonium (AmjOO,) is the important gronp-reagent — the precipitant of barium and calcium.
Mote 2. — In the above, and iu subsequent charts of analytical processes, the leading precipitants will be found to be ammonium saltfl. These being volatile, can be got rid of towards the end of the operations, and thus the detection of potassium and sodium be in no way prevented— an advantage which could not be had if snch salts as chromate of potassium or phosphate of sodium were the group- precipitants employed.
Note 3. — Acetic, and not hydrochloric or nitric, acid is used in dissolving the barium and calcium carbonates, because chromate of barium, on the precipitation of which the detection of barium de- pends, is soluble in ite stronger acids, and therefore could not be thrown down in their presence.
Note on Olctssificaiion. — The compounds of barium, calcium, and m^neaium, like those of the alkali metals, have many analogies; the carbonates, phosphates, and arseniates of each are insoluble, which BufBciently oistinguishes them from the members of the class first studied. They possess, moreover, well-marited dilferences, so that their separation Irom each other is easy. The solubOity of their hydrates in water mark their connection with the alkali metals; the sliglitneBS of that solubility, diminishing as we advance further and
id .y Google
ANALYSIS. 95
furtlier from the alkalies, baryta being most and magnesia least solu- ble in water, poiats to their connection with the next class of metals, the hydrates of which are insoluble in wafer. These considerations must not, however, he over-valned. Thongh the solubility of their hydrates places barinm nearest and magnesium furthest from the alkali metals, the solnbility of their sulphates gives them the oppo- site order, magnesium-sulphate being most soluble, calcium-sulphate nest, fitrontinni-sulphate third (strontium is a rarer element, which will be mentioned subsequently), and barium-sulphate insoluble in water. Tliese elements are sometimes spoken of as the metals of the alkaline earths.
Note.— In connection with the bivalence of tlie metals Barium, Calcium, and Magnesium, it is interesting to note that just as biva- lent acidulous radicals give sails containing two atoms of univalent basylous radicals (S^SO,, NaHSO^, H.COj, KNaO.H^O,), so biva- lent basylous radicals yield salts containing two atoms of univalent acidulous radicals, as seen in aeetonitrate of barium, BaCjHjOsNO,, a salt which is a definite compound, and not a mere mixture of ace- tate with nitrate of barium. A very large number of such salts is
Distillation.
The water with which, in analysis, solution of a salt or dilution of a liquid is effected should be pure. Well or river-water {aqua, U. S. P.) is unfit for the purpose, because containing alkaline and earthy salts (about 20 to 60 grains per gallon), derived from the soil through which the water percolates, and raiu-water is not unfre- quently contaminated with the dust and debris which fall on the rooft whence it is usually collected. Such water is purified by dis- tillation, an operation in which the water is by ebullition converted into steam, and the steam condensed again to water in a separate vessel, the fixed earthy and other salts remaining in the vessel in which the water is boiled. On the large scale, ebullition is effected in metal boilers having a hood or head in which is a lateral opening through which passes the 3f«am ; on the small scale, either a common glass flask is employed, into the neck of which, by a cork, is inserted a glass tube bent to an acute angle, or a retort is used, a sort of long-necked Florence flask, dexterously bent near the body by the glass-worker to an appropriate angle (hence the name retort, from retorqueo, to bend back). Gondensatton is effected b^ surrounding the lateral steam-tube with cold water. In large stdls the sfeam- tube, or condensing-worm, is usually a metal (tin) pipe, twisted into a spiral form for the sake of compactness, and so lixea in a tub 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 water heated by the con- densing steams runs off from the top of the column. The condenser for a flask or retort may be a simple glass tube of any size, placed within a second much wider tnbe (a common long, narrow lamp-glass answers very well for expei-imental operations), the tube being eon-
id .yCoOglc
86 THE METALLIC RADICALS.
nect«d at the extremities of the wider by bored corks; a stream of water passes into one end of the inclosed space {the end fnrtheat from the retort), through a small glass tube inserted in the cork, and out at the other through a Biniimr tube. The common (Liebig's) form of laboratory condenser is a glass tnbe three-foarths of an inch, wide and a yard long, surronnded by a Bhorf«r tin or zinc tube two inches in diameter, and having at each extremity a neck, through which the glass tube passes. The ends of the necks of the tin tube, and small portions of the glass tube near them, are counected by means of a strip of sheet caoutchouc carefully bonnd round. An ajerture near the lower part of the tin tube provides for the admi^ Bion of a current of cold water, and a similar aperture near the top allows the escape of heated water. The inner tube may thus con stantly be snrrounded by cold water, and heated vapors paasmg throngh it be perfectly cooled and condensed.
In oistilling several gallons of water for analytical or medicmal purposes (Aqua Destillata, B. P. and TJ. S. B.), the first two oi three pin& should be rejected, because likely to contain ammoniacal and other volatile impurities.
Beet^cation is the process of redistilling a distilled liquid. Seeii- fied spirit is spirit of wine thns treated.
Dry or destructive distillation is distillation in which the condensed prodnctfi are directly formed hy the decomposing influence of the heat applied to the dry or non-volatile substances in the retort or still.
EXERCISE. 174. Writ* from memory two or three paragraphs descriptive of
ZINC, ALITMINIUM, IRON.
These three elements are classed together for analytical rather than for more general analogies.
znTc.
Symbol Zn. Atomic weight 65. Source. — Zinc is tolerably abundant in nature as sulphide (ZnS) or blende, and carbonate (ZnOOj) or calamine (from calamus, a, reed, in allusion to the appearance of the mineral). The ores are roasted to espel snlphnr, carbonic acid gas, and some impnrities, and the resulting oxide distilled with charcoal, when the metal vaporizes and readily condenses.
Uses. — lis use as a metal is familiar; alloyed with nickel it yields german silver ; with twice its weight of copper forms common brass, and as a coating on iron (the ao-called galvanised iron) greatly
id .y Google
Reactions having (a) Synthbtioal and (b) Analytical
I NT EKE ST.
(a) Synthetical Beactions. Snipliate of Zinc. Pirst SyntfiMical Eeaciiov,. — Heat zinc (i pta.) with water (20 pts.) and sulphnric acid {3 fl. pts.) in a test-tube (or larger vessel) until gas ceases to be evolved ; solution of sulphate of zinc (ZnSO,) results. Filter and concentrate the solution in an evaporating dish; on cooling, color- less, transparent, prismatic crystals of Sulphate of Zinc (ZnSO,, 1H,0) are deposited {Zinci Sulphas, B. P. and U. S. P.).
Note. — This reaction affords hydrogen and sulphate of zinc; it also gives electricity. Of several methods of evolving tydi-ogen, it is the most convenient; of the two or three means of preparing sulphate of ainc it is that moat commonly employed; and of the many reactions which may be utilized In the development of dynamic electricity it is at present the cheapest and most manageable. The apparatus in which the reaction is effected differs according to the requirements of the operator i if the sulphate of zinc alone is wanted, an open dish is all that is necessary, the action being, perhaps, accelerated by heat; if hydrogen, a closed vessel and" delivery-tube;
materials, forming altogether what is termed a battery, operation for one product the other two are commonly wastett. it would not be difficult for the operator, as a matter of amusement, to construct an apparatus in which all three products should be collected. Purification. — Impure sulphate of zinc may be purified in the same manner as impure chloride (see next reaction).
Chloride of Zinc.
Second Synthetical Beaclion — Dissolve zinc in hydro- chloric acid mixed with half its bulk of water; the resulting solution contains chloride of zinc Evaporate the liquid till no more steam escapes ; Chloride of Zinc (ZnClj) iu a state of fusion remains, and, on cooling, is obtained as a white opaque solid I^Zinci Chloridum, B. P. and TJ. S. P.). It is soluble in water, alcohol, or ether.
Zn + 2HC1 = ZnCl, + H„
Zing, njrdi'ochlQiiB Ghloriile Hydtogea.
id .y Google
THE METALLIC EADI0AL8
moat acida, with formation of solable salts : they mw be recognized io the liquids by applying the testa described hereafter to a, little of the solution in a test-tube (p. 99). Should eithev be present in tlie above solution, a little chlorine water is added to the liquid till the odor of chlorine is permanent, and then the whole well shaken with some carbonate of dnc. In this way iron is precipitated as ferric hydrate, and lead as peroxide : —
*2FeCL + CL = * Fe,Cl.
Ferrous ehloriae. Chlorine. Fenlo chloride.
FejCl, + SZnOO, + 3HjO = FejenO + BZuOlj + 300, . PbOL + OL + 2ZnOO, = PbO, + 2ZnOL + 2C0,
Chloride Chlorine. Gaiboaale Peromlda Clilorlde Carbouio
ofleBd. ofrino. ofload. of^no. Bold gas.
In the British Pharmacopceia the pesence of impurities in the zinc is assnmed, and the process of puriication just described incor- porated with the process of preparation of Zind Ohloridwrn, Ldquor Zinci GMoridi, and Zinci S-idphas. In the purification of the sul- phate of Bine, the action of chlorine on any fevrons eulphate will result in the formation of ferric sulphate as well as ferric oliloride : —
6FeS0, + 01, = 2(Fe,3SOJ + Pe.Ol, carbonate of Bine will then give chloride as well as snlphate of zinc, and thus the whole qnaniity of snlphate of zinc be slightly contami- nated by chloride. On evaporating and ciystalliaing, however, the chloride of zinc will be retained in tie mother liquor.
For lAqnor Zinci GMoridi, B. P., 1 pound of zinc is placed in a mixture of 44 fluidounces of hydrochloric acid and 20 of wa1«r, the mixture ultimately warmed until no more gas escapes, filtered into a bottle, chlorine water added until the liquid after shaking smells fyrly of chlorine, abont half an ounce or somewhat more of carbonate of amc shaken up with the solution until a brown precipitate (of ferric hydrate, or peroxide of lead, or both) appears, the whole filtered and the filtrate evaporated to 40 fluidouucea.. If there is reason to believe that neither iron nor lead is present in the zinc, the treatment witl chlorine, water, and carbonate of zinc may be omitted.
Carbonate of Zinc.
Third Synthetical Reaction. — To sohition of any given quantity of sulphate of zinc in twice its weight of water (in a test-tube, evaporating basin, or other large or small
* It will lie noticed tiiat the iron is lepresHiitel, in these equations, as esertiiig both liivalent and trivalent activity ; this w'ill be ailaded to when iron coiubs under ooiisideralion.
id, Google
vessel), add about an equal quantity of carbonate of so- dium, also dissolved in twice its weight of water, and boil; ttie resnlticg white precipitate is so-called Carbonate of Zinc (Zinci Garbonas, B. P., Zinci Carhonas Precipilata, U.S. P.), a mixture of carbonate (ZnCOj) and hydrate (ZnSHO), in the proportion of one molecule of the former and two. of the latter, together with a molecule of water {HgO), It may be washed, drained, and driecl in the usual manner. It is used in the arts under the name of zinc- white-, and frequently in medicine in the form of ointment ( Oeratum Zinci Garbonatis, V. S. P.). 3ZnS0. + 2H,0 + SKa.OOa = ZnC0„3ZnH,0, + 2C0,
+ 3Na,S0,
Acetate of Zinc, Fourth Synthetical Beaction. — Collect in a filter the pre- cipitate obtained in the last reaction, wash with distilled water, and dissolve a portion in strong acetic acid ; the resulting solution contains acetate of Bine (Zn3C,H„0J, and, on evaporating, aud setting aside for a daj', j'ields lamellar pearly crystals (Zn2C^Il30j,2H^O}. This is the process for Zinci Acetas, B. P. ZnC0„2ZnH,0, + GHC^H^O, = 3(Zn2C,H,0,} + ^H,,0
+ 00,
Ciivtooiili!
The U. S. P. process consists in precipitating by metal- lic zinc the lead in a solution of acetate of lead, evaporat- ing and crystalJining.
Oxide of Zinc.
Fifth , Synthetical Beaction. — Dry the remainder of the precipitated carbonate (by placing the open filter on a plate over a dish of water kept boiling), and then heat it in a small crucible till it ceases to effervesce on the addition of water and acid to trial samples taken out of the crucible from time to time ; the product is Oxide of Zinc {Zinci Oxidum, B. P. and U. S. P.), much used in the form of ointment ( Unguentvm Zind, B. P. and Unguentuvi Zinci Oxidi, TT. S. P.).
id .y Google
) THE METALLIC 1
XiiCO,, aZnll.Oa = 3ZnO
Note. — This oxide is of a very pale yellow or buff tiat, not nearly so whit* as oxide prepared hy the combustion of zinc in air. The latter variety occurs in commerce under the name of Hubbnck's oxide of zinc. Its preparation can on]y he practically accomplished on the large scale, but the chief features of the action may be observed by heating a piece of zinc in a small porcelain crucible till it burns ; flocks escape from the crucible, float about in the air, and slowly Ml. Thrae are the old Flores Zind, Lana Pkilosophiea, or Nthu- tim Album.
Valerianate o&Zlho.
Sixth Synthetical Seaction — Valerianate of Zinc (ZnSC^ HgOJ Zinci Valerianas, B. P. and TJ. S. P.) is prepared by mixing strong solutioEs of sulphate of zinc and valerianate of sodium, cooling, separating the white pearly crystalline matter, evaporating at 200° to a low bulk, cooling, again separating the lamellar crystals, washing the whole pro- duct with a small quantity of cold distilled water, draining and drying by exposure to air at ordinary temperatures. Valerianate of zinc is soluble in etiier, alcohol, or hot water.
ZnSO, + aNaC-H.O, = Na,80, + Zn2CjH„0,
Sulpliftte VB-loriniiHlo of Sulphate of Vilerianale
The compoands of zinc described in the above six reactions are the only ones mentioned in the British Fbarmacopceia ; the processes are also those of that work. Sulphide and Hydrate of Zinc are mentioned in the following analytical paragraphs : —
(6) Reactions having Analytical Interest (Tents),
First Analytical Eeaction. — To solution of a zinc salt (sulphate for example) in a test-tube, add solution of sul- phydrate of ammonium (NH^HS); white sulphide of zinc (ZnS) is precipitated, insoluble in acetic, bat soluble in the stronger acids.
Note. — This is the only white sulphide that will be met with. Its formation, on the addition of the sulphydrate of ammonium, is there- fore highly characteristic of zinc. If the zinc salt contains iron or lead as impurities the precipitate will have a dark appearance, the snlpbides of those metals being black. Hydrate of aluminium, which is also white and precipitated by sulphydrate of ammonium, is the only substance sulphide of zinc is likely to be mistaken for, and vice vfrsd; but, as wiU be seen immediately, there are good means of distinguishing these from each other.
id .y Google
ZINO. 101
i Analytical Reaction. To solntiou of a ziiie salt add solution of ammonia; wliite hydrate of zinc (Zn2H0) ie precipitated. Add excess of ammonia; the precipitate is redissolved.
Other Analytical Beactions — Tlie fixed alkali liydratea afford a similar reaction to that juBt mentioned, the hydrate
of zincredisaolvingif the allialiis fl-ee from carbonate.
Carbonate of ammoninm yields a white precipitate of car- bonate and hydrate, soluble in excess. The fixed alka- line carbonates give fi similar precipitate, which ia not redissolved if the mixed solution and precipitate be well boiled.
Antidotes. — Tliere are no efficient chemical means of counter- acting the poiBOnons effects of zinc. Large dceea, fortnnately, act as powerful emetics. If vomiting has not occurred, or appai'eDtly to an insufficient extent, solution of carbonate of Eodinm (common .washing salt) immediately followed by white of egg and dcniulccQts may be adminiatered.
QUESTIONS AND EXEECISES.
175. Give the sources and uses of metallic zinc.
176. Explain by a diagram what occurs when ainc"is dissolved in dilute sulphuric acid.
177. How may solutions of Chloride or Sulphate of Zinc be puri- fied from salts of iron? Give equations descriptive of the reactions.
178. State the formula of Carbonate of Zinc, and illustrate by a diagram the reaction which takes place in its production.
179. Give an equation showina; the formation of Acetate of Zinc.
180. In what respect do^ Oxide of Zinc, resulting from the igni- tion of the carbonate, difier fi-om that produced during the combus- tion of the metal !
181. How is Valerianate of Zinc prepared ?
182. "What are the pi-opertiea of valerianate of Zinc?
183. Name the more important tests for zinc.
184. How would you distinguish, chemically, between solutions of Sulphate of Zinc and Alum?
185. Describe the treatment in cases of poisoning by salts of ainc.
9*
id .y Google
102 THE METALr.IO RADICALS.
AIUMINIUM.
Symbol Al Atomic weight 27.5. Note.- — In the formulee of alimiiniTiro salts, it will be observed that to one atom of metal there are three atoms of other univalent radi- cals ; hence, apparently, the atom of aluminium is trivalent, Al'". But possibly it is quadrivalent; for one molecnle of aluminium com- ponnda includes two atoms of the metal, three-fourths only of whose power may be supposed to be exerted in retaining the other constitu- ents of the molecule, the remaining fourth enabling the aluminium fttflms themselves to keep tog^ether. This is graphically shown in the following formula of chloride of aluminium (AljOlj) from Frank- land's " Lecture Notes for Chemical Students," which represents each
aluminium atom as a body having four arms or bonds, three of which are engaged in grasping the arms of univalent chlorine atoms, while the fourth grasps the corresponding arm of its brother aluminium atom. Such graphic formute, as they are called, are useful in facilitating the acquirement of hypotheses regarding- the constitution of chemical substances, especially if the error be avoided of supposing that they are pictures either of the position or absolute power of atoms in a molecule, or indeed, the true representation of a molecule at all ; for on this point man knows nothing.
Source. — Aluminium is vei^ abundant in nature, chiefly as sili- cate, in clws, slate, marl, granite, basalt, and a large number of minerals. The sapphire and ruby are almost pure oxide of aluminium. The metal is obtained from the double chloride of aluminium and sodium, by the action of metallic sodium, the source of the chloride being the mineral bauxite.
Amrntmum-brome is an alloy of ten parts of aluminium with ninety of copper.
Al-am (Alumen, B. P.), a double sulphate of aluminium and ammonium (Al^SOj, Am^SO,, 24HjO), {AlitmincE ef Ammonix Sidphas, U. S. P.), is obtained from aluminous schist {from dz"^^!, aehistos, divided), a sort of pyritous slate or shale, by exposure to air ; oxidation and chemical change produce sulphate of aluminium, sulphate of iron, and silica, from the silicate of aluminium and hisnl- phide of iron (iron pyrites) originally present in the shale. Tlie sulphate of aluminium and sulphate of iron are dissolved out of the mass by water, and sulphate or chloride of ammonium added; on concentrating the liquids alum ciTstallizes out, while the more solu- ble iron salt remains in the mother-liquor.
Alums. — There are several ahirns, iron or chromium replacing aluminium, and potassium or sodium taking the place of ammonium, all crystallizing in one eight-sided form, the octahedron — a sort of double pyramid. These are, apparently, alike in chemical consti-
id.y Google
ALUMINIUM. 103
tutioii, and tlieir geiiRral formula (M=eitlier metal) is M"'j3S04, M'^Oj, 24HjO. The alum of the manufacturer commonly occurs in colorless, transparent, octafaedral cvjatals, massed in lumps, which , are roughly broken up for trade purposes, but still exhibit the faces of octahedra.
Sulphate of Ahimjnmm {AljSSOj, 9HjO), or Alum Cake, pre- pared from natural silicates in the manner just described, is a common article of trade, serving moat of the manufacturing purposes for which alum was formerly employed. In the United States Pharmaoopteia {Alummw Sulphas) it is directed to be made by dissolving hydrate of alumiuiam in aQnted sulphuric acid with subseqnent removal of water by evaporation.
Alj6H0 + SHjSO, = A1,3S0, + 6HjO. The hydrate of aluminium is to be prepared by the addition of solu- tion of aium to solution of carbonate of sodium, the precipitated hydrate being collected on a filter and well washed.
s weight of sulphuric acid for some time, dissolving ont the n
_ 1 to the clear-filtered solution until, after well stirring,
it is faintly acid to test-paper ; on evaporating, crystals of alnm are obtained.
.The Ammonzo-fernc Alum of American pharmacy {Ferri et AmmonicB Sulphas, tJ, S. P.) is made by adding sniphate of ammo- nium to a hot solution of persnlphat« of iron, and setting the liquid aside to crystallize. It forms pale violet octohedral crystals, ex- pressed by the formula rej3S0,, (NH,),80., 242,0. Alumten [V. S. P.) is potassium alum, the siuphate of aluminium and potassium (AI^SO^ KjSO^, 24H,0).
Dried aium {Alumen Ex&iccafwm, B. F. and U. S. P.) is alum from which the water of crystallization has been expelled by heat, the tetoperature not exceeding 40(P. By calculation from the mole- cular weight of alum, it will be found that the salt contains between 41 and 48 per cent, of watef. At temperatures above 400° alum is decomposed, sniphate of ammonium and sulphuric anhydride escap- ing, and pure alimiina (AljOj) remaining. Dried alum rapidly reabsorbs water from the atmosphere. It is almost useless as a medicinal preparation.
Keactions having Analytical Interest.
First Analytical Reaction. — To a solutionof an ainrainium salt (alum, for example, which contains sulphate of alumi- nium) add sulphydrate of ammonium (NH^HS) ; a gelati- nons white precipitate of bydrate of aluminium falls: —
A1.^3S0, + 6AmHS + 6H^0 = A1,6H0 -F .3Am,SO,-f-6H,S.
id .y Google
104 THE METALLIO RADICALS.
Second Analytical Reaction. — To solution of alum add ammouia, NlIjHO ; bjdvate of aluminium falls: add excess of ammonia ; the precipitate is insoluble.
Principle of Dyeing by help of Mordants. — The precipi- tated hydrate of aluminium, or alumina, has great affinity for vegetable coloring-matters, and also for the fibre of cloth. Once more perform the above experiment, but be- fore adding the ammonia introduce some decoction of log- wood, solution of cochineal, or other similar colored liquid, into the test-tube. Add now the ammonia, and set the tube aside for the alumina to fall ; the latter takes down with it all the coloring principle. In dye-works the fabrics are passed through liquids holding the alumina but weakly iu solution, and then through the coloring solutions; from the first bath the fibres abstract alumina, and from the second the alumina abstracts coloring matter. Some other metallic hydrates, notably those of tin and iron, resemble alumina in this property; they are all termed mordants (from mordens, biting); the substances they form with coloring-matters have the name of lakes.
Tliird Analytical Reaction. — To the alum add solution of potash; again hydrate of aluminium fall?. Add excess of potash, and agitate ; the precipitate dissolves.
Alumina may be precipitated from this solution by neu- tralizing the potash with hydrochloric acid, and adding ammonia until, after shaking, the mixture has an ammoni- acal smell, or by adding solution of chloride of ammonium to the potash liquid. But the former way is the better; for it is difficult to know when a sufficiency of the chloride of ammonium has been poured in, whereas reaction with blue and red litmus-paper at once enables tbo operator to know wben excess of hydrochloric acid or ammonia has been added.
Alkaline carbonates, phosphates, arseniates, and salts of other aci- dulous radicals also decompose solutions of aluminium salts and pro- duce insoluble compounds of that metal, with the several aciduloi adicals (except the lO special interest.
QUESTIONS AND EXEEOISES.
186. What is there remarkable about the quantivalence of alumi-
187. Practically what is the qnanti valence of the atom of alumi-
id.y Google
IRON. iOS
188. Enumerate the chief natural compounds of aluminium.
1 89. Write down a formula which will represent either of the Alnma.
190. Which alum is official, and commonly employed in the arts?
191. State the source, and explain the formation, of alum.
192. What is the crjatalline form of alnm? Work a sum show- ing howmuchDried Alum is theoretically producible from 100 pounds of alum! Ana. 52 .lbs. 6 02B.
193. Show by figures how ordinary ammonium a!um- is capable of yielding 11,356 per cent, of alumina.
194. Why are aluminium compounds used in dyeing!
195. How are salts of aiuminiam analytically distmguishod from those of Bine?
Symbol Pe. Atomic weight 56.
Sources. — Compounds of iron are very abundant in nature. Mag- netic Iron Ore, Or Loadstone (Lodestone or Leadstone, from the Saxon te(iaw,tolead, in allusion to its use, or rather of magnets made from it, in navigation) is the chief ore from which Swedish iron is made; it is a mixture of ferrousandfemc oxidenFeOjFejO,). Much of the Russian iron is made from Specular Iron Ore (from speciUiim, a mirror, in allusion to the lustrous nature of the crystal of this mineral). This and Red ffcematite (from x^i^, aima, blood, so named ittym the color of ita streak), an ore raised in Iiancashire, are composed of ferric ozide only (FCjO,). Brown Hamatite, an oxy- hydrate, is the source of much of the French iron. Spathic Iron Ore (from spallia, a slice, in allusion to the lamellar structure of the ore) is a ferrous carbonate (PeCOj). An impure ferrous carbonate forms the Glai/ Ironstone, 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. Iron Pyrites (from mill, pur, fire, in allusion to the production of sparks when sharply struck) (FeSj) is a yellow lustrous mineral, of use only for its sul- phur. Ferrous earbonat« (FeOOj), chloride (FeClj.iHjO), and sul- phate (FeS0j,7H_0} sometimes ocenr in spring, the water of which is hence termed ckalyheaXe {chalybs, steel).
Process.— Iron is obtained from its ores by processes of roasting, and reduction of the r^ulting impure oxide with coal or charcoal in the presence of chalk, the latter uniting with the sand, clay, &c., to form a fusible slag. . The cast iron thus produced is converted into wrought iron (Perrum, tl. S. P.) by burning out the 4 or 5 per cent, of carbon, silicon, and other impurities present, by oxidation in a furnace, an operation termed puddling. Steel is wrought iron impregnated with from one to two per cent, of carbon by strongly heating in charcoal. The official variety of the metal (Ferr)(m,E. P.), the condition in which it is most easily employed for conversion into its compounds, is " wrought iron in the form of wire or nails free from oxide." In the form of a fine powder (see 17 Reac.) metallic iron is employed as a medicine.
Quanivoalence. — Iron combines with other elements and radicals
id .y Google
106 THE METALLIC KADIOALS.
in two proportions ; tlioae ealts in which the afflm of iron appeara to possess inferior afBniti^ (in which the other radicals are in the less amount) are termed ferrous, the higher being ferric salts. In the former the iron exerte bivalent {Fe'7, in the latter trivalent activity (Pe"'orFvl.
The atom oi iron is also sometimes considered to be sexivalent, on ftcconnt of the analogy of its componnds with those of chrominm, which is sexivalent, if the formula of its fluoride (OrPj) be correct, and because the composition ot ferrate of potassium (E^FeO,), a deep-purple salt obtained on passing chlorine throu ;; h a concentrated solution of potash in which fresh ferric hydrate is suspended, is best explained on the assumption of the sexivalenoe of its iron.
"Why the quantivalence of the atom of iron should vary is not at present known.
!77ie Nomendatiire of Iron Salts. — For educational and descrip- tive purposes the two clftSjses of iron compounds are very conveniently spokMi of as ferrous and ferric, the syllable "ferr" common to all indicating their allied feiToginous character, the syllable oms and ic indicating the lower and higher class respectively — ftmctions tulfiUed by these two syllables in otner similar cases (^sulphurous and sulphu- ric, mercurous and mercuric). Offtoially the iron salts are known by other names, thus. Sulphate of Iron (Ferri Stdphas), and PJtos- phate of Iron (Ferri PhospMs), names which are chemically inex- plicit, for there are two sulpnates, and two phosphates, and the terms do not define which salt is intended. Consistency and uniformity would demand that the names Ferrous Sulphate, Ferrous Phosphate, or similar terms should be employed. Practically, however, the old names cause no confusion, inasmuch as only one sulphate, phosphate, &c., are HSed in medicine ; moreover, the higher salts usually have the prefix per attached (as persulphate, perchloride). These names are already well known, can be easily rendered in liatin, and then admit of simple abbreviations and adaptations such as are employed in pre- scriptions, advantages not possessed by the more rational terms. While therefore the comprehension of tiie chemistry of iron is ren- dered simple and intelligible by the use of the terms ferrous and ferric, the employment of older and Jess definite names may- very well be continued in pharmacy as being practically more convenient.
Eeactions having (a) Syhthetical and (6) Analytical Interest.
(a) Synthetical Seadions.
FEUaOUS SALTS.
Green Sulphate of Iron. Ferrous Sulphate.
First Synthetical Eeaclion. — Place iron (small tacks) in
sulphuric acid diluted with eight times its bulk of water
(in a test-tube, basin, or other vessel of any required size),
accelerating the action by heat until effervescence ceases.
id .y Google
Fe, + 2H,S0, = 2FeS0. + 2H,
Iron. Snlphiirio EoriouB UyAvognn.
add. sulphals.
The solution contains what is generally known as Sul- phate of Iron, that is Ferrous Sulphate, the lower of the two sulphates, and will yield crystals of that substance {FeSO„THaO) (Ferri Sulphas, B. P. and TJ. S. P.) on cool- ing or on further evaporation ; or if the Lot concentrated solution be poured into alcohol, the mixture being well stirred, the sulphate is at once thrown down in minute crystals (Ferri Sulphas Qranulata, M. P.)- ^^ ^ tempera- ture of 400° F. ferrous sulphate loses six-sevenths of its water, and becomes the Ferri Sulphas Exsiccata, B. P. and U. S. P.
Other Sources of_ Ferrous Sviphate. — In the laboratory, ferrotis Bnlphate is often obtained as a hy-produot in making snlphnretted hydrogen,
Fe8 + H,SO, = HjS -|- FeSO,. In manuractories it occurs as a hy-prodnct in the decomposition of ftlnminous shaie, as already noticed {p. 103).
Ten grains of granulated sulphate of iion dissoUel m ne out e of water constitntes "Solution of Sulphate of Iiui B P The Bolntion shonld be recently prepared."
Notes. — Ferrous sulpliate is Bometimes termed green, iiti/cl Titriol (from vitrum, glass) was originally the name of any tians parent crystalline substance, but afterwards restricted Id the sni phates of ainc, iron, and copper, which were and still are octasion ally known as white, green, and blue vitriol Copperas (probably originally Copper-rust, a term applied to verdigns and other green incrostations oi copper) is anotner name for this sulphate (f iron sometimes distingnisliecl as green cameras sulphate of copper being blue copperas. Solid aulphate of iron is a constituent of Fitula Aloes e( FewV, B. P.
Ferrous sulphate, when exposed to the air gradually turns brown throngh absorption of oxygen, ferric oxysnlphate (Fe,02S0,) bemg formed. The latter is not completely dissohed hywatei owing to the formation of a still lower insoluble oxysalt (Fe.O^fciO,) and solu- hie ferric sulphate (PesSSO.).
Iron heated with undiluted sulphuric acid gives sulphurona acid gas and ferrous sulphate :—
Fe^ + 4H^80, = SO, + FcSO, +2TI^0 Carbonate of Iron. Ferrous Carbonate.
Second Synthetical Seaction^-^To solution of ferrous sul- phate, boiling, in a test-tube, add a solution of carbonate of ammonium in recently boiled water ; a white precipitate of ferrous carbonate (FeCOj) is thrown down, rapidly be- coming light green, bluish green, and, after a long time,
id .y Google
I RADICALS,
red, through absorption of osygen, evolution of carbonic acid gas, and formation of ferric oxyhydrate.
FeSO, + Am^CO, = PeCO, + Am.SO,
Sacckarated Garhonate of Iron. — The above precipitate, rapidly washed with hot well-boiled distilled water, and the moist powder mixed with sugar and quickly dried — in short, all possible precau- tions taken to avoid exposure to air — forms the aaccharated carbo- nate of iron {Ferri Carbonas Saccharata, B. P.).
The official proportions are two ounces of the anlphatc and one ounce and a quarter of the carbonate, each dissolved in half a gallon of hot water ; the solutions are mixed and set aside in a deep well- covered pan, the supernatant liquid poured off when the precipitate has subsided, the pan again filled np with boiling water, the liquid once more poured away, the precipitate transferred to a calico filter, drained, gently pressed, and while still somewhat moist rub- bed in a mortar with one ounce of sngar, and finally dried over a water-bath.
Carbonate of Iron, mixed with a fourth its weight of Oonfeotioa of Eoses (Honey and Sugar, U. S. P.), forms the Pilida Ferri Car- Icmab'B, B. P. and U. S. P.
N'otes.—'Vhs Subcarbonateof IroniFemSubcarhonas,!!.^.^.) ia precipitated on mixing solutions of snlphate of iron and carbonate of sodium. On washing and drying it is converted into reddish- brown oxyhydrate of iron, watei- being absorbed and carbonic a«id gas being eliminated. This oxyhydrate of iron is best made by pre- cipitating solution of persulphate of iron by solution of soda, and washing and drying the product,
Saccharated ferrous carbonate is said to be more easily dissolved in the stomach than any other iron preparation. It is so unstable and prone to oxidation, that it must be washed in water containing no dissolved air and mixed with the sugar (which protects it from oxidation) as quickly as possible. In making the official compound mixture of iron (Mistura Ferri Gomposita, B. P. and U. S. P,), " GrifBth's mixture," the various ingretuents, including the carbonate of potassium, should be placed in a bottle of fie required size, space being left for the crystals or solution of ferrous sulphate, which should be added last, the bottle immedi ' ' "" ' water, and securely corked ; oxidation i greatest po^ble extent. jHIiU<b Ferri
lately filled up with r 1 thus prevented to the CornpomtiE, U. 8. P.,
made from myrrh, carbonate of sodium, sulphate of iron and syrup carbonate of iron is gradually formed.
FeSOj + K,CO, = FeCO, -J- K,SO,
Arseniate of Iron. Eerrous Areeniate. Third Synthetical Reaction, by which the lower arseniate of iron, ferrous arseniate {Ferri Arsenias, B. P.) (Fe^
id .y Google
2A80J, partially oxidized, is formed. This will be noticed again under Araenieum.
Phosphate of Iron. Ferrous Phosphate.
Fourth Synthetical Reaction. — To solution of ferroua sulphate in a test-tube add a little solution of acetate of sodium, then solution of phosphate of sodium ; the lower phosphate of iron, ferroua phosphate (Fej2P0,), ia precipi- tated {Ferri Fhosphas, B. P. and XT. S. P.).
STeSO, -i- 2Na,HP0, + 2NaOXO,
Pon-ona Phosphals of Acetala of
suLi»iKte. Bodium. sodiuni.
= re,2P0^
OtBcially, solutions of 3 ounces of sulphate of iron in a quart of ■water, and 2J- ounces of phosphate and 1 of acetate of sodium in another quart of wat«r, are well naixed, filtered, the precipitate well washed, and, to prevent oxidation as much. as possible, dried at a temperature not exceeding 120° P. These proportions will be found to accord with the molecular weights of the crystalline salts, mnlti- plied as indicated in the foregoing equation. 3{FeS0., 7HjO)=834: 3(Na,HP0„ 12H,0)=716; 2(NaC,H,0s, 3H,0)=272.
The use of tlie acetate of sodium (not mentioned in the U. 8. P. formula) is to insure the occurrence of acetic acid In the solution, where otherwise would be free sulphuric acid. Sulphuric acid is a solvent of ferrous phosphate; acetic acid is not. It is impossible to preyent the separation of sulphuric acid, if only ferrous sulphate and phosphate of sodium be employed. Ferrous phosphate is white, but soon oxidiaes and becomes slate-blue.
The above reaction also occurs in malting Syrv,pus Ferri Phos- phalis, B. P.
Sulphide of Iron, Ferrous Sulphide. Fifth Synthetical Meaclion. — The formation of ferrous sulphide (FeS). In a gas- or spirit-flame strongly heat autpbur with about twice its weight of iron filings in a test-tube (or in an earthen crucible in a furnace); ferrous sulphide is formed. When cold, add water, then a few drops of sulphuric acid; sniphnretted hydrogen gas (H^S), known by its odor, is evolved.
FeS + H^SO^ = FeSO, + H,S.
Sticks of sulphur pressed against a white-hot bar of cast iron give
the purest form of feirons sulphide. The liquid sulphide thus formed
is aUowed to drop into a vessel of water (Sulphide of Iron, B. P.;
Ferri Sulphuretum, U. S. P.).
10
id .y Google
THE METALLIC EADICALS.
Green Iodide of Iron. Ferrous Iodide.
Sixth Synthetical Beaclion. — Place a piece of iodine, aljout the size of a pea, in a test-tube witli a small quantity of water, and add a few iron filings, small nails, or iron wire. On gently warming, or merely shaking if locger time be allowed, the iodine disappears, and, on filtering, a, clear light green solution of iodide of iron (E'elj) is ob- tained.
The official Ferri lodidum is formed by gently warming a mix- ture of 3 . parts of iodine, li of fine iron wire, and 12 of distilled water in an iron vessel. Wien combination is nearly complete (as shown by indicationB of a sea-green tint), boil for a short time until the whiteness of the froth proves that the iodine has entirely disap- peared. The solntion is then filtered and evaporated in a clean bright iron sancepan, ladle, or dish until a drop taken ont on the end of an iron wire stirrer solidifies on cooling. The liquid is ponred ont on a clean smooth slab, broken np and preserved in a glaae-stoppered bottle. Solid iodide of iron has a crystalline fracture, is "green with a tinge of brown ; inodorons, deliquescent, and almost entirely soluble in water, forming a slightly green solntion which gradually deposits a colored sediment and acquires a red color."
The solid iodide contains about 18 per cent, of water of crystalliza- tion, and a little oside of iron.
Ferrovs bromide (FeBi'j), occasionally used in medicine, coald be made, as might he expected, in the same way as the iodide.
fERRIC SALTS. Anhydrous Perchloride of Iron.- Ferric Chloride.
Seventh Synthetical Seaction. — Pass chlorine (generated as usual, from black oxide of manganoso and hydrochloric acid in a flask) throngh sulphuric acid contained in a small bottle, and thence by the ordinary narrow glass tubing to the bottom of a test-tnbe containing twenty or thirty small iron tacks {or a florence flask containing 3 or 3 ounces of iron tacks), the latter kept hot by a gas-flame; the higher chloride of iron, ferric chloride, or the perohloride* of iron (FCjCIb) is formed and condenses in the upper part of the tube or flask as a mass of small dark iridescent crystals.
* The prefixes per and hi/per used here and elsewhere are from liirif, vper or hi/per, over or above, and simply "meau "the hiyheat" of several. Thus p^rchloride, the highest chloride.
id, Google
IltON. Ill
When a tolerably thick crust of the salt is formed, break off the part of the glass containing it, being caiefiil that the remaining coruoded tacks are excluded, and place it in ten or twenty times its weight pf water; the resulting solu- tion, poured off from any pieces of glass, is a pure neutral solution of hydrous ferric chloride, and will be serviceable in performing analytical reactions.
Precaution. — The above experiineut must be condueted m the open air, or in a cupboard having a draught outwards.
Anhydrous Perro-us Chloride. — la brealting np the tube, small scales of a light buff color will be observed adnermg to tho nails ; they are crystals of ferrous chloride (FeCI,).
JVoie.— Solntion of ferric chloride evolves some hydrochiorie acid on boiling, while a darker-colored solation of ferric oxjchloride
Oreec Chloride of Iron. Hydrous ferrous Chloride. Solution of Hydrous Ferric Chloride.
Eighth Synihelical Reaction, — Dissolve iron tacks, in a test-tube, in hydrochloric acid; hydrogen escapes, and the solution on cooling, or on evaporation and cooling, deposits crystallized ferrous chloride (Feeij,4H^0). _
Through a portion of the solution of fe'rrous chloride pass chlorine gas ; the ferrous chloride becomes ferric chloride.
The excess of chlorine dissolved by the liquid in this experiment may be removed by ebullition ; bat the ferric chloride is slimtly de- composed at the same time, for the reason jast stated. The free chlorine may also be carried off by passing a current of air through the liquid for some time.
Hydrons Ferric Chloride (another process}. Ninth Synthetical Beaetion.—To another portion of the solution of ferrous chloride, in a test-tube, add a little more hydrochloric acid; heat the liquid, and continue to drop, in nitric acid until the black color it first produces disappears ; the resulting reddish-brown liquid is also so- lution of ferric chloride.
6Fe01, -f- 2HN0, + 6HCI = 3Fe,OI„ + 2N0 + 4H,0.
The black color is due to solution of nitric oxide gas (NO) in a portion of the ferrous salt; it is decomposed by heat.
This is the process for producing the Liquor Ferri Perckloridi
id .y Google
112 THE METALLIC RADICALS.
Fortior, B. P., 2 ounces of iron, 12 fluidoTiiicea of hfdroclilorio acid, 9 flnidra«hms of nitric acid, and 8 onnues of water being employed, and tlie prodnct boiled down to 10 flaidonnces. Prac- tically it is impossible so to apportion the acids that a eolation shall result containing neither excess of acid nor of metal, nor contain ferric nitrate. For most medicinal pnrposes, however, solution of perchloride of iron containing hydrochloric acid is said to be nnob- Jeetionable.
Diluted with 3 volnmea of water this strong solution gives the LdquoT Ferri Ferehloridi, B. F. — or with 3 volumes of rectified spirit the Ttndiiira Ferri Perchloridi, B. P. The Tindii/ra Fei-ri ChloriiU, TJ. 8. P., is a similar solution.
Note. — The spirit in the Tinctnre is naneeeesary, useless, and dele- terious ; for it acts neither as a special solvent nor as a preservative, the offices nsually performed by alcohol (Knciwrte et Select, B. P. aud U. S. P.) ; bn^ nnlras the liquid contain excess of acid, decom^ poses the ferric chloride and causes the formation of an insoluble oxychloride of iron. Even if the tinctnre be acid, it slowly loses color, ferrous chloride and chlorinated ethereal bodies being formed. A Liquor, of similar strength, is doubtless destined to displace the tinctnre altogether.
Solution of ferric chloride evaporated yields a mass of yellow crystals (Ferri Chloridum, U. S. F.) containing PojCle 12H,0, or, rarely, red cryatals having the formula PejClg 5HjO. An old method of making solution of fen'ic chloride is fe dissolve ferric oside or hy- drate in hydrochloric acid ; but from the varying character of trade specimens of the ingredients, the liquid is more likely to contain ex- cess or deficiency of iron than the proper proportion.
Fersnlpliate of Iron, Ferric Sulphate. Tenth Synthetical Reaction. — Diasolvo about three- quarters of an ounce of ferrous sulphate and a sixth of its weight of sulphuric acid in an ounce and a half of water in an evaporating dish, heat the mixture aud drop iu nitric acid until the black color it first produces disappears ; the resulting liquid, when made of a certain prescribed strength {vide IZth lieao.), is the solution of ferric sul- phate, the higher sulphate or Persulphate of Iron {Liquor Ferri Fersulphatis) of the British PharmacopOBia, a heavy dark-red liquid, sp, gr. 1.441. The lAquor Ferri Tersul- pkatis, U. 8. P., is the same preparation but slightly stronger (sp. gr. 1,320). Liquor Ferri SubsulpJiatis, V. S. P. (Monsel's solution), is a similar finid, made with less acids, probably containing, therefore, ferric oxysul- phate and ferric oxjuitrate (sp. gr. 1.552).
6FeS0^ -|-3H,S0. + SHNO, = 3{Fe,3SO,) + 2N0 + 4H,0.
id .y Google
IRON. 113
The black color, as in the previous reaction, is due to a compound of ferrous salt with nitric oside (2FeS0,+N0).
Note.— Id all the reactions in which iron passes from ferrous to ferric condition the element assumes different properties, the chief being aa alteration from bivalent to trivalent activity.
Acetate of Iron. Ferric Acetate.
Eleventh SynUietioal ReacUon. — To a strong solution of ferric sulphate (from which, free nitric acid lias been re- moved by evaporating to dryness and redissolving in water) add an alcoholic solution of acetate of potassium (EC5H3 0,), and well shake the mixture ; a crystalline precipitate of sulphate of potassium (K^SOJ falls, and ferric acetate (Fe^GC^UjO,) remains in solution, forming, when filtered, and of definite strength, the Tinotura Ferri Acetatis,'S.'P . The preparation is unstalsle.
Pe,3S0^ + 6KO,HjO, = 3K,S0, + Fe^BCH-jO,
The official proportions are 2J- fluidounces of " Solution of Per- sulphate of Iron" {vide 10th Reac.) with 8 flnidounoes of rectifled spirit, mixed with a solution of 2 ounces of acetate of potassium in 10 fluidounces of spirit, the whole well shalten frequenlly during an hour, filtered, and the precipitated sulphate of potassium washed by pouring on spirit until the filtj»te measures 1 pint. A solution fo\ir times Qiia strength, made from ferric hydrate and glacial acetic acid, is stable : it is diluted with spirit as wanted (J. Deane and T. Jeaffreson).
Perhydrate of Iron. Ferric hydrate. Twelfth Synthetical Reaction. — Ponr a portion of the solution of ferric sulphate into excess of solution of soda (ammonia, U. S. P.) ; moiat ferric hydrate is precipitated {Ferri Peroxidum Eumidum, B. P., Ferri Oxidum ffydra- tum, U. S. P.).
Fe,3S0,
Either of the other alkalies (potash or ammonia) will produce a similar reaction; but soda is cheapest and most convenient.
Ferric hydrate is an antidote to arsenic if administered directly ifter the poison has been taken.
It converts the soluble arsenic (ASjOj) into insoluble ferrous arse-
2(Fe,6H0) + Asfi, — Pe,2AB0, + 5H,0 + Fe2H0.
id .y Google
114 THE METALLIC RADICALS.
Dried fevric hjdrate (then become an oxjhdrate — Fej0,4H0) (Ferri Peroxidum Hydratmn, B. P.) has no action on arsenic. Even the moist recently prepared hydrate (Fe^eHO) ceases to react with arsenic as aoon t^ it has become converted into an oxyhydvate (FeiOjSHO), a change which occura though the hydrate be kept under water. According to T. and H, Smith this decomposition occura ^adually, but in an increasing ratio; so that after four moatha the power of the moist mass ia reduced to one-half, and after fiye months to one-fourth. Now mere loss of water is not usually followed by any alteration of the essential chemical properties of a compound It would seem, therefore, that ferric hydrate (two niulecnlcs) (Fe,12H0) probablysuffera, on standing, actual decompo- sition into oxyhydrate {FejO,6HO) and water (3H^), and does not meibly lose water already existing in it as water. Ferric hydrate is also far more readily soluble in hydrochloric acid, tartaric acid, citric acid, and acid tartrate of potassium, than ferric oxyhydrate. Any formula exhibiting ferric hydrate (Pe^6H0) as a combination of ferric oside and water (Fej03,3H;0) is, apparently, for these and other reasons, incorrect.
Peroxyhydrate of Iron. Ferric Peroxyhydrate.
Collect the precipitate on a filter, wash, and dry on a
plate over hot water; ferric oxyhydrate {Fe.rri Peroxidum
Hydraium^ B. P.) (Fe,0,,SHO) remains. When rubbed to
powder it is fit for use in medicine.
Fe^eEO = Fe,032EO -f 2H,0.
This oxyhydrate further decomposes when heated to low redness, ferric oxide (Fe503) remaiuing.
Fo,0,2nO = PePs 4- H^O. Peroxyde of Iron. Eeriio oxyde.
The sis univalent atoms of the HO, the chorafiteristic elements of all hydrates, are thus, by two enecessive steps, split up into water and oxygen. Bnt between the hydrate and oxide there obvioi may be another oxyhydrate, in which iHO is displaced hj 0'\, such a compound ia well known ; it ia a variety of brown iron ore. The other oxyhydrate, FejOj2HO, is also native (needle iron ore}, as well as being the Ferri Feroxidwrn. Hydratum,, B. P.
" Ferri Peroxiflum Humidnm" Fo"'j 6H0
A variety of brown iron ore Fe"'5 0"4HO
" Fen'i Peroxidum Hydratum" (needle ore) Fe'", 0"j2H0
Ferric oxide Fe'", 0",
The moist fcrric hydrate, when kept for some months, even nnder water, loses the elements of water ( W. Proctor, Jr.), and is converted into an oxyhydrate, having the formula Fe^HjO, (limonite or brown
id .y Google
IRON. 115
hicniatite), wliicii ia either a compound of tlie above oxyhydratea iPe504HO) + (Fe50,2HO), or is a definite intermediate oxjhydrate '(FoAGHO).
By ebullition with water for scveu or eight hours ferrii" hydrite is deeomposed into water, and an osyhydrate having the foi inula Fe^HjO, (Saint-Gilea), which is either a mixture of the oihcial oxy hydrate (FejO^HO) with ferric oxide (FSjO,), or a definite inter mediate body (Fe,052HO). The relation of these bodies to each other will be apparent from the following Table, in which foi con- venience, the formulee of ferric hydrate and oxide are doubled
Ferric hydrate (B. P.) (as stalactite) . . . Fe^ 12H0
Kilbride mineral (?) Pe. OlOHO
Brown iron ore (Huttenrode and Easchau) , Fe^ Oj8HO
Old ferric hydrate (limonite) Pe, Oa6HO
Ferric oxyhydrate (B. P.) (gothite) . . . Fe, 0,4HO
Boiled ferric hydrate (turgite) Fe, O52HO
Ferric oxide (red hiematite) Fe^ Oj
The official ferric oxyhydrate (FejO,2HO)-, termed in the British Pharmacopceia Hy&rated Peroadde of Iron, under the assumption that it ia a compound of ferric oxide and water (PejOj.HsO), was formerly made by mizing solutions of ferrous sulphate and carbonate of sodium and exposing the resulting ferrous earbooate lo the air until it was nearly all converted into ferric oxyhydrate ; hence its old name, still sometimea seen on old bottles, of Ferri Carbonas and Ferri Sabcarbonas.
Ferric Oxide (another process).
Thirteenth Synthetical Beaction — Uoaat a crystal or two of ferrous sulphate in a staall crncible until fumes cease to be evolved ; the residue is a variety of ferric oxide (Fe^OJ or peroxide of iron, known in trade as red oxide of iron, colcothar, crocus, rouge (mineral), or Venetian red. It has sometimes been used in pharmacy in mistake for the official oxyhydrates (vide 12th Synthet,B.eac.), from which it differs not only in composition but in the important respect of being almost jasoliible in acids.
The Seale Componnds of Iron,
Fourteenth Synthetical Beaction. — Repeat the previous (13th) reaction, introducing a little solution of citric or tar- taric acid, or acid tartrate of potassium, before adding the alkali {soda, potash or ammonia), and notice that now no precipitation of ferric hydrate occurs. This is due to the formation of double compounds, termed A m mo nio- Citrate, Potassio-Citrate, Ammonio-Tartrate, Potassio- Tartrate,
id .y Google
116 THE METALLIC RADICALS.
and similar Sodium compounds of Iron, which retnaiii in solution along with the secondary product— sulphate of the alkali metal. Soch ferric compounds, made with cer- tain prescribed proportions of recently prepared ferric hydrate (from which all alkaline sulphate has been washed), and the respective acids (tartaric or citric) or acid salts {acid tartrate of potassium), and the solutions evaporated to a syrupy consistence and spread on flat plates till dry, form the scaly preparations known as Ferri et Ammonia Gitras, B. P. and tf. 8. P., Ferri Citras, U. S. P. {B\soLiquor Ferri GUr Otis, U. S. P.), Ferri et Ammonise Tartras, U. 8. P., and Ferri Polassio4arlras, or rather, Ferrum Tartaratum, B.F., Ferri et PotassmTartras, U.S. P. A mixture of ferric citrate with citrate of quinine yields, by similar treatment, the well-known scales of Ferri et Quinas Gitras, B. P. and TI. S. P. Specimens of these substances may be prepared by attending to the following details.
In tlie plionnacoptEial processes for tlie three scaly ■ ' ' 'ijifcate is in each caae fresh made from i ' "
hjitate is in each caae fresh made from solution o by precipitation with solution of a '
Fe,3S0, + eAmBO = Pe,&H
the solution of ferric sulphate being made of a definite strength from a known weight of ferrous sulphate. The reason for adopting this course is that ferric hydrate is unstable and cannot be weighed, be- cause it cannot be dried without decomposing and becoming insoluble, as explained under the 12fh reaction. This definite solution of ferric Bulphate {Liqitor Ferri PeraulvhatiB, B. P., Liquor Ferri Tersid- phatis, tr. S. P.) is made by adding six fluidraehms of sulphuric acid to half a pint of water, warming, dissolving eight ounces of crystals of sulphate of iron in the liquid, pouring in nitacacid(sixfinidrachms or rather more) slightly diluted until the mixture turns from a black to a reddish color, and ruddy nitrons vapors cease to be produced; the whole should measure eleven iluidounces, being diluted or further evaporated, as the case may be, to this bulb.
6FcS0, + 3H,S04 -t- 2HN0j = 3(Fej3S04) + 2N0 + 4H,0.
Ferri et Ammonix Citras, B. P. and TJ. 8. P.^ — Ferric hydrate is dissolved in solution of citric acid, ammonia added, and the whole
evaporated to dryness.
To prepare the ferric hydrate, dilute eight fluidounces of the above solution of ferric sulphate with about a quart of water; pour this inte two or three pints of water containing excess of solution of am- monia (atwut 5 fiuidounces of "Strong Solution of Ammonia," or 15 ounces of "Solution of Ammonia"). Thoroughly stir the mixture (if it does not then smell of ammonia, more of the latter should be
id, Google
laoN. in
added), allow the precipitate to subside, pour away the supernatant liquid, add more water, aud repeat the washing nntii a little of the liquid tested for bj-produot (sulphate of ammonium) by solution of chloride or nitrate of barium ceases to give a white precipitate (sul- phate of barium). Collect the ferric hydrate on a filter, drain, and place, while still moist, in a mortar with four ounces of citric acid. Set aside the mixture for a few hours, occasionally stirring to pro- mote contact of the constitueufs, transfer to an evaporating basin, and heat over a water-bath, with frequent stirring, until the whole, or nearly the whole, of the hydrate has diraolved. To the solution, when cool, add nearly two ftaidounces of strongest (or five and a half of weak) solution of ammonia, filter, evaporate over a water- bath to the consistence of syrup, spread on panes of glass, and dry (at a temperature not exceeding 100° P.). The product scales off the glass in deep red transparent laminie.
Ferri et Quimce Oitras, B. P. and U. 8. P.— Ferric hydrate and pure quinia are dissolved in solution of citric acid, ammonia added, and the whole evaporated to dryness.
The ferric hydrate is obtained from four and a half fiuidounces of the solution of ferric sulphate, with all the precautious described in the previous paragraph, a proportionate quantity of ammonia being employed.
While the ferric hydrate is being washed, prepare the quinia by dissolving one ounce of the ordinary sulphate of quinia in eight ounces of distilled water, acidified with sufficient sulphuric acid to dissolve the sulphaf* (about 12 fluidrachios of the omcia! "diluted sulphuric acid"), and to the clear liquid add solution of ammonia, well mixing the product by stirring, outil the whole of the quinia is precipitated (that is, until the mixture, after thorough a^tation, smells of ammonia). Collect the precipitate on a filter, let it drain, and wash away adhering solution of sulphate of ammonium b^ passing through it about a pint and a half of distilled water. (It will be ob- served that the principle involved in the preparation of quinia from its sulphate is identical with that which obtains in the precipitation of alumina, ferric hydrate, or hydrate of zinc, &c, A solunle sul- phate— or, indeed, any common soluble salt — has its acidulous con- stituent removed by the superior afSnity of the basylous radical in ammonia, or other alkali, an insoluble precipitate and a new soluble sulpl^te being formed. The latter is washed away, leaving the former pure. In such manipulations, when economy has to be prac- tised, soda is the alkali generally employed. Ammonia, however, has the advantage of showing the moment when its work of removing an acidulous radioaJ is completed; for the salts which it forms with such acidulous radicals as 80„ 01, NO,, and O^HjOj are inodorous, while it itself has a powerftil odor; so long, therefore, as the salt to be decomposed is not wholly attacked, the additiou of ammonia does not give an ammooiaoal odor to the mixture, the ammonia, as such, being, in fact destroyed; but when the work is accomplished, the quantity ' I last added remains as ammonia, and communicates its
natural smell to the liquid.) The ferric hydrate and quinia being now washed and drained, dia-
id.y Google
lis THE metallic; radicals.
solve the former, and afterwards the latter, in a solution of three onDces of citric acid in five of distilled water, the acid liquid being warmed over a water-bath, and portions of the precipitates stin'ed in as fast as solution is effected. "Let the solution cool, then add in small quantities at a time twelve fluidraohma of solution of ammonia dilnted with two ftuidounces of distilled water, stirring- the solution briskly, and allowing the qniuia which separates with each addition of ammouia to dissolve before the neist additioii is made. Filter the solution, evaporate to the consistence of a thin syrup, and then dry in thin layers on flat porcelaiu or glass plates at a temperature of 10<P. Remove the dry salt in fl^es, and keep it in a stoppered bottle." Long-continued exposure to sunlight causes opacity in the scales, andreuders them difficultly soluble (Wood.)
Ferrvan Tartaratum, B. P. ; Ferrt et PotasscE Tartraa, U. S. P, — Ferric hydrate is dissolved in solution of acid tartrate of potassium, and the whole evaporated to dryness.
The ferric hydrate obtainable from five and a half flnidounces of the official solution of fbrric sulphate by the action of ammonia, in the manner detailed in the previous ijaragraphs, is mixed(in a mortar), while still moist but well drained, with two ounces of acid tartrate of potassium. The whole is se^ aside for twenty-four hours, with occa- sionally rubbing to promote contact and reaction of the molecules t otherwise somewhat sluggish in attacking each other), and then eated in a dish over a water-bath to a temxteratnre not exceeding 14SP F.; a pint of distilled water is then added, and the mixture kept warm until nothing inore will dissolve. Filter, evaporate at a temperature not exceeding 14(P (greater heat causes decomposition), and when the mixture has the consistence of syrup, spread on panes of glass and dry (in any warm, light place shown by a thermometer to be not hotter than 140°). Remove the dry salt in flakes, and keep it in well-closed bottles.
Ferri ei AmraoniiB Tartras, V. S. P., is made by saturating solu- tion of acid tartrate of ammonium with ferric hydrate, evaporating, and scaling. The acid tartrate is prepared by exactly neutralizing half of any quantity of tartaric acid by carbonal* of ai then adding the other half
The foregoing are the only official scaly j , Many others of similar character might be formed. None crystallizi or give other indications of definite chemical composition. Their properties are only constant so long as made with unvarying propor- tioQS of constituents. Their want of chemical compactness, the loose state in which the iron is combined, 'precludes their recognition as weU-defined chemical compounds, yet possibly enables them to be more readily assimilated as medicines than some of the more definite ferrous and ferric salts.
Wine of Iron, or "Steel" wiae (Vinvm Ferri, B. P.), made by digesting iron wire in sherry wine, probably contains tartrate of po- tassium and iron and other iron satte, formed b^ action of the metal on the acid tartrate of potassium and tartaric, citric, malic, and acetic acids present in the wine. Vinum Ferri Citratis, B. P., is a solution lo citrate of iron in orange wine.
id .y Google
Black Hydiate of Iron, rerro-ferrio Hydrate.
Fifteenth Synthetical Reaction. — To two-thirds of a sroall quantity of a solution of ferrous sulphate add a little sul- phuric acid; warm, and gradually add nitric acid, as de- scribed in the tenth reaction, care being taken not to allow one drop more nitric acid than necessary to fall into the test-tube. Add the other third of ferrous sulphate, shake, and pour the liquid into excess of an alkali; black hy- drate of iron, or ferro so-ferric hydrate (Fej8HO=Pe2HO, Fe^SHO), is produced.
BulpLato. snlphate.
It is SO readily attracted by a magnet, even when moist, as to collect round the latter when immersed in the super- natant liquid. Hence the B. P. name, Ferri Oxidum Magneticum..
In this process the nitric acid oxidizes the hydrogen of the snl- phnrio acid, the snlphnric radical uniting with the ferrona sulphate, whose iron is at the same time altered from the ferrous to the ferric radifjon, ferric sulphate being formed. If too mnch nitric acid be
red ferric hydrate. This result may be avoided bj evaporating the solution of ferric Enlphate oearly to dryness, thus boiling off excess of nitric acid, or by pouring first the ferric and then the ferrous liipiid mto the alkali and thoroughly stirring the mixture; the nitric acid IB then neutralized and rendered incapable of osidizing the ferrous sulphate sntisequently added.
Black hydrate of iron is deeomposecl by heat, yielding, iu a closed vessel oijhydrates and, finally, black oxide of iron or ferroso.ferric oxide Healed in the air it absorbs oxygen and gives ferric oxide. The black forge-scales, which collect near the blacksmith's anvil, have the composition of ferroso-ferric oxide ; the black magma formed on exposing a mixture of iron and water to the air is ferroso- ferric hydrate ; but these varieties are apt to contain particles of metal and, beuc«, give hydrogen gas when dissolved in acids — a char- acter which distinguishes them from the official prepai'ation.
If a dried specimen of the black hydrate of iron be required, the mixture should be well boiled and then set aside for am hour or two to favor aggregation of the particles, the mixture filtered, and the precipitate wasned nntil the washings contain no trace of sulphate (indicated by a white precipitate with chloride of barium), ISlack hydrate of iron absorbs oxygen even at the temperature of the water-bath ; it should eonsequently be dried at 120*^, a degi'ee at which only slight oxidation occurs.
id .y Google
THE METALLII
Femitxate of Iron. Perrie TTitrate. Sitrieenth Synthetical Reaction. — Place a few iron tacks in dilute nitric acid and set aside; solution of ferric nitrate, or pernitrate of iron, is formed (Pe^6N0J. Fe^ + 8HN0, = Fe,6N0, + 4H,0 + 2N0
This solution, made with care, and of a prescribed strength, forms the Ldquor Ferri Pernilralts, B. B. (sp. gr. l.lOl) and U. 8. P. (sp.gr. 1.065).
Four and a half fluidounces of nitric acid are diluted with sixteen onnces of distilled water, and one ounce of iron wire, free from rust, dissolved in the mistnre, the latter being kept cool t* avoid violence of action. The liquid is finally filtered and diluted to thirty fluid-
Bedticed Iron. Seventeenth Synthetical Reaction. — Pass hydrogen gas (dried by passing over pieces of chloride of calcium con- tained ia a tube, or through sulphuric acid in a wash- bottle) into a small quantity of ferric oxyhydrate or oxide ("subcarbonate," U. 8. P.) contained in a tube arranged horizontally (a test-tube, the bottom of which haa been accidentally broken, answers very well), the oside being kept hot by a gas-tiame; oxygen is removed from the oxide 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 minute state of division, remains.
Fe^Og + 3Hj = Fe, + 3H,0
While still hot throw the iron out into the air; it takes Are and falls to the ground as oxide.
If the ferric oxide is reduced in a gun-barrel heated by a strong ftimace, tlie particles of iron aggregate to some extent, and, when cold, are only slowly oxidized in dry air. This latter form of reduced iron is Fer r^duii, or Quevemie'e Iron, the Ferri pyivis, or Ferrwn Redactum, B. P. and U. S. P. — "a fine f[rayi8h-bla«k powder, strongly attracted by the magnet, and exhibiting metallic streaks when nibbed with firin pressure in a mortar." It is often administered in the form of lozenges (Trockisci Ferri Bedacti, B. P.) gum and sugar protecting the iron from oxidation as well as forming a vehicle for its administration.
id .y Google
JEON. 121
NoU. — The spontaneona igEitian of the iron in the above esperi- meat is aa illnstration of the influeuce of minute division on chemical affinity. The action is the same as occurs whenever iron rnsts, and the heat evolved and amount of oxide formed is not greater Irom a given quantity of iron ; but the surface exposed to the action of the oxygen of the air is, in the case of this variety of reduced iron, so enormous compared with the weight of the iron, that heat cannot be conducted away sufficiently fast to prevent elevation of temperature to a point at which the whole becomes iocandesceot. In the slow rusting of iron, escape of heat occurs, but is not observed, because spread over a length of time ; in the spontaneous ignition of reduced iron the whole is evolved at one moment.
Terric Pjrropiiospliate. Eighteenth Synthetical Reaction. — To sohition of pyro- phosphate of sodinm add solution of persulphate of iron ; a yellowish-white precipitate of ferric pyrophosphate (Pe, SPjOj, 9H5O) separates. This precipitate, dissolved in so- lution of citrate of ammonium, and evaporated, yields apple-green scales (Ferri pyrophosphas, TJ. S. P., contain- ing forty-eight per cent, of anhydrous pyrophosphate).
(&) Reactions having Analytical Inlereftt (Tests). (The iron occurring as a ferrous salt.)
First Analytical Beaciion. — Pass sulphuretted hydrogen (11,8) through a solution of a ferrous salt (e.g., ferrous sulphate) slightly acidulated by hydrochloric acid; no precipitate occurs.
This is a valuable negative fact, aa will be evident pre- sently.
Sec(md Analytical Reaction. — Add sulphydrate of am- monium (NHjHS) to solution of a ferrous salt; a black precipitate of ferrous sulphide (FeS) falls.
FeSO, + 2AmHS = FeS + Am,SO. + H,S.
Third Analytical Reaction. — Add solution of ferrocyor nide of potassium (yellow prussiate of potash) K,Fe"Cy„, or KjPcy"", to solution of a ferrous salt; a precipitate (K^Fe"Fcy) falls, at first white, but rapidly becoming blue, owing to absorption of oxygen.
Fourth Analytical Reaction. — To solution of a ferrous salt add ferridcyanide of potassium (red prussiate of pot- ash), K„Fe"',Cy^, or KoPdcy; a precipitate {Fe"^Fdcy)
n
id .y Google
reaembling Prussian blue (TurnbuU'a blue) is thrown down.
Other Analytical Beactions.—The pi-ecipitates produced from ferrous solutions on the addition of alkaline carbo- nates, phosphates, and arseniates, as already described in the synthetical reactions of ferrous salts, are characteristic, and hence have a certain amount of analytical interest, but
! inferior in this respect to the four reactions above
Note. — The alkalies (solution of potash, soda, or ammo- nia) are incomplete precipitants of ferrous aalta, and are therefore almost useless as tests. To solution of a ferrous salt add ammonia {NH,HO) ; on filtering and testing with Bulpbydrate of ammonium, iron will still be found in the solution. To another portion of the ferrous solution add a few drops of nitric acid and boil; this converts the fer- rous into ferric salt, and now alkalies will wholly remove the iron, as already twice seen during the performance of the synthetical experiments.
In actual analysis, the Beparation of iron aa ferric hydrate is an operation of frequent performance. This is always accomplished by the addition of alkali, and, if the iron occurs as a ferrous salt, by previous ebullition with a little nitric acid. Ferroejanide and fer- ridcyanide of potassium are the teats used in distiaguishing ferrous from ferric salts.
(The iron occurring as a ferric salt.) Sixih Analytical Reaction. — Through a ferric solution (ferric chloride, e.g.) pass sulphuretted hydrogen ; a white precipitate of the sulphur of the sulphuretted hydrogen falls, and the ferric is reduced to a ferrous salt, the latter remaining in solution. This reaction is of frequent occur- rence in practical analysis.
2Fe,Clg 4- 2H,S = 4FeCl„ + 4HC1 + \. Seventh Analytical Jieaction. — Add eulphydrate of am- monium to a ferric solution ; the latter is reduced to the ferrous state, and black ferrous sulpbido (FeS) is precipi- tated as in the second analytical reaction, sulphur being set free.
Eighth Analytical Reaction. — To a ferric solution add ferrocyanide of potassium (K,FeCy„, or K,Fcy"") ; a pre- cipitate of Prussian blue, the common pigment, occurs (Fe'" 3Fe"Cyi„ or Fe"',Fcy""B). (Ferri Ferrooyanidum, U. S. P.)
id .y Google
^RO^f. 123
Nirdh Analytical EeacHon. — To a ferric solution add solatioQ of femdcyauide of potassium ; no precipitate occurs, but the liquid is darkened to a greenisii or olive liue, according to the strength.
Tenth Analytical Beaction. — Thia is the production of a red precipitate of ferric hydrate, on the addition of alka- lies to ferric salts, and is identical with the twelfth syn- thetical reaction.
Note. — This reaction illnBtrates the conventioaal character of the terms synthesis and analysis. It is of equal importance to the manu- facturer and tie analyst, and is synthetical or analytical according to the intention with which it is performed.
Other ferric reactions have occasional analytical inter- est. In neutral ferric solutions the tannic acid in tincture of galls occasions a bluish-black inky precipitate, the basis
of ordinary writing ink. (The Mistiira Ferri Aromalica,
of the British Pharmacopoeia, made by digesting metaliio iron in an infusion of various vegetable substances, con- tains tannate, or rather tannales of iron ; it is commonly known in Ireland by the name of Heberden's Ink, after the physician by whom it was first used. It contains about
1 grain of iron in 1 pint.) Sulphocyanate of Potassium
(KOyS) causes the formation of ferric sulphocyanate,
which is of a deep blood-red color. There is no ferric
carbonate ; alkaline carbonates caase the precipitation of ferric hydrate, while carbonic acid gas escapes.
Note. — Cyanogen (NO, or Cy'), ferro-oyanogen (FeCjN„, or FeOyfl, or simply Pcy""), and ferridcyanogen (Fefij,^, or Fdcy"), are radicals which play the part of non-metallic elements, jnst as am- monium in its chemical relations resembles the metallic elements. They will be again referred to.
Memorandum, — The reader must on no account omit to write out equations or diagrams expressive of each of the reactions of iron, analytical as well as synthetical. It is presumed that this has already been done immediately after each reaction has been performed.
id .y Google
THE METALLIC RADICALS
DIEECTIONE FOK ArPLYINO THE rOEEQOING ANALYTICAL KEAC- TIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION 01' SALTS CONTAINING ONE OP THE METALS, ZiNC, ALUMI- NIUM, Iron. Add solution of ammonia gradnally: — A dirty-green precipitate indicates iron in the state of a ferrous salt.
A red precipitate indicates iron in the stateof a ferric salt, A white precipitate, insoluble in excess, indicates the presence of an aluminium salt.
A white precipitate, soluble in excess, shows zinc. These results may be confirmed by the application of some of the other testa to fresh portions of the solution.
TABLE OE SHORT D1EECTI0N8 FOE APPLYING THE FOREGOING ANALYTICAL EEACTIONS TO THE ANALYSIS OF AN AQUE0V3 SOLUTION OP SALTS OP OH*B, TWO, QK ALL THHBE OF THE METALS, ZINC, ALUMINIUM, IRON.
Boil about half a tesl-tubeful of the solution with a few drops of nitric.acid. This insures the conversion of ferrous into ferric salts, and enahles the next reagent (ammonia) completely/ to precipitate the iron. Add excess of ammonia, and shake the mixture. Filter.
Precipitate Al Fe* n HCl, add excess of KHO, stir, filter.
(red ppt.).
Neutralize by HCl, and
add excess of AmHOf
(white ppt.).
Test hy AmHS. (white ppt.).
» The alnminium preoipitatB (AI36HO) is white, the iron (FejfiHO) red. It the precipitate is red, iron must be and aluminium may be present; if white, iron is absent, and further operation on the preoi-
t Alumina, when in small qaantity, is somettmea prevented from being precipitated by ammonia through the presence of organic mat- ter doriced from Ihe filter paper by action of the potash. In cases of doubt, therefore, before adding ammonia boil the liquid nith a litLla nitrio aoid, wljivh destroys any organic matter.
id .y Google
ZINC, ALUMINIUM, lEON. 125
Nole I.^If iron ia present, portions of the original so- Intion roust be tested by ferridcyanide of potaasium for ferrous, and by ferrocyanide for ferric salts; dark-blue precipitates with both indicate both salts.
Note II. — If no ferrous salt is present, ebullition with nitric acid is unneceaaary. It is, perhaps therefore idvi- sftble always to determine this point by \ rev ously test ng a little of the original solution with ler idcyan le f lo blue precipitate occurs, the nitric ao 1 treatme t i ij be omitted.
Chakt for all Metals hitherto considered
Tlie following Table {vide Table, p. 126) a p«ri aps the best but not tlie only adaptation of the orainMy react ons to ystemat c analysis. It is little else than the addition of tl e analytical scheme for the third group to that of the first two gronps As before ana lysis is commenoea by the addition of chloride of amroooinm (NH,01J to prevent partial precipitation of magnesium, and ammonia (^NHjHO ) to neutralize any acidt The latter wonld attack the chief group- precipitant, Bulphydrate of ammonium (NH,HS), preventing its useful action, and causing a precipitation of the sulphur it common- ly contains.
Note. — When a teat g-ives no reaction, absence of the body sought for may be fairly inferred. If group-tests (that is, teats which pre- cipitate a group of substances) give no reaction, the analyst is saved the trouble of looking for either member of that gronp.
id .y Google
METALLIC KADICALS.
|
•; |
||
|
alS |
||
|
^ |
.ICa |
|
|
ri« |
."i-i |
|
|
.1 |
l^il-^ |
|
|
-2^ a |
g.ass |
|
|
M . |
"fP |
|
|
• J |
f |
H-^ |
|
l^w |
t^ |
^ |
|
fit ;S O |
? |
&4 |
|
og |
o'H- |
|
|
. S^ |
|°|| |
|
|
£* at. |
||
|
»'iS- |
||
|
|1 |
4 |
|
|
^ |
||
|
?l |
' t; |
5 ^t |
|
Ss |
1 oS a |
|
|
as |
i^il |
|
|
H |
||
|
PH^K „ |
||
|
.3" |
||
|
ii |
||
|
■5&& |
||
|
5i |
S^S |
|
|
^" |
i'1 |
id, Google
ALUMINIUM,
QUESTIONS AND EXERCISES.
1@6. Name tbe chief ores of iron.
197. How is the metal obtained from the ores J
198. What is the chemical difference between cast iron, wrought iron, and steel ?
Ifl9. What is the natnre of chalybeate waters?
200. Illustrate by formulfe the difference between ferrous and fer- ric salts.
201. Under what different circumstances may the atom of iron be considered to exert bivalent, trivalent, and sexivalent a«tivity !
202. Write a paragraph on the nomenclature of iron salts.
203. Give a diagram of the official process for the preparation of ferrous sulphate.
204. In what respects do Sulphate of Iron, Granulated Sulphate of Iron, and Dried Sulphate of Iron differ?
205. How ia ferrous sulphate obtained on the large scale ?
206. Mention the chemical names of white, green, and bine vitriol.
207. Why does ferrous sulphate become brown by prolonged ex- posure to air ?
208. Give a diagram showing the formation of Ferrous Carbonate.
209. Describe tlie action of atmospheric oxygen on ferrous carbon- ate ; can the effect be prevented ?
210. In what order would you mix the ingredients of Mutura Ferri Comiposita, and why ?
211. Write out an equation illnstrative of the formation of the Phosphate of Iron.
212. Why is acetate of sodium used in the preparation of ferrous phosphate ?
213. Which four compounds of iron may be formed by the direct union of their elements t
214. Give the official method for the preparation of Solution of Ferric Chloride.
216. Of what use is the spirit in Tincture of Perchloride of Iron ?
216. How may Ferrous be converted into Ferric Sulphate?
217. What is the formula of Ferric Acetate? and how is it pre- pared for use in pharmacy?
218. Express,byformnlfe,the difference between Pern' /"eroandtnn Rvmddum, B. P., and Ferri Peroxidum Sydratwm, B. P.
219. What are the general characters and mode of production of the medicinal scale preparations of iron ?
220. In what state is the iron in Vinivm Fern, B.P.?
331. What other form of Wine of Iron is official in Great Britain ?
222. Give equations illustrating the chief steps in the artificial production of uie so-called Magnetic Oxide of Iron.
233. How is precipitated magnetic oxide of iron distinguished from the varieties made directly from the metal ?
334. Why is magnetic oxide of iron officially directed to be dried at a temperature not exceeding 120° Fahr.?
335, Give a diagram showing the formation of Ferric Nitrate.
id .y Google
128 THE METALLIC RADICALS.
226. Work out a gnm showing Low much anhydrous ferric oxide will yield, theoretically, one handred weight of iron. Ans. 160 lbs.
227. What are the properties of anhymoua ferric oiide ?
228. Give the characteristic testa foi iron, distinguishing between ferrous and ferric reactions and illustrating each by an equation or a diagram : —
a. Snlphydrate of ammonium
b. Percocyanide of potwsium
c. Ferridcyanide of potassium
d. Canstic alkalies.
e. Sulphocyanate of potisiium
229. Describe the action of ainmonn on salts of iron, aluminium, and zinc respectively.
230. What precautions roust be used in testing for calcium in the presence of iron ?
231. How is magnesium detected in the presence of zinc !
232. How is aluminium detected in presence of magnesium 1
233. Draw up a scheme for the analysis of au aqueoua liquid con- taining salts of iron, barium, and potassium.
234. How may zinc, magnesium, and ammonium be consecutively removed from aqueous solution i
ARSENICUM, ANTIMONY.
These two elements resemble metals in appearance and in the character of some of their compounds; but they are still more closely allied to the non-metals, especially to phosphorus and nitrogen. They are quinquivalent (As*, Sb'), as seen in arsenic anhydride (AsjOj) and pentachloride of antimony (SbClj), but usually exert trivalent activity only (An™, 8b™), as seen in the hydrogen and other compounds (AsHj, AsClj, AsBTj, AsIj). A few preparations of these elements are used in medicine; but all are more or less powerfnl jioisons, and hence have considerable toxicological interest. The iodide {Arsenid Jodidvan, U. 8. P.) is made hj cautiously fusing together atomic proportions of arsenicum and iodine. It is an orange-red crystalline solid soluble in water. The Liquor Arsenid et Uydrargyri lodidi, X5. 8. P., is made by dissolving iodide of arsenicum and red iodide of mercury in water, in the proportion of 1 grain of each of tiie solids to 104 grains of water.
ASSENICTTM.
Symbol As. Atomic weight '15.
Sowces. — Arsenical ores are frequently met with in nature, the commonest being the arsenio-sulphide of iron (FeSAs). This mineral is roasted in a current of air, the oxygen of which, combimng with the arsenicum, forms common white arsenic (A&fi^) {Acidum Arseni-
id.y Google
ARSENICUM. 129
OEwti, B. p. and U. S. P.), which, is condeneed in chambere or long: flues. It commonly " occurs as a heavy white powder, or in Kublimed masses, which uenally present a stratified appearance, caused by the existence of separate layera, differing from ea«h other in degrees of opacity." Realga/r (red alg-ar) is the red native sulphide (Ae^Sj), and orpiraent Umripigmentum, the golden pigment) the yellow native sulphide (As^Sj) of arsenicum.
Reactions having (o) Synthetical and (6) Analytical Interest.
(o) Reactions having Synthetical Interest. Alkaline Solution of Arsenic. Fir&t Synthetical Beaclion. — Boil a grain or two of pow- dered arsenic (As^O,) in water containing an equal weight of carbonate of potassium, and, if necessary, filter. The solution, colored witli compound tincture of lavender, and containing i grains of arsenic per ounce, forms the Liquor Arsenicatis, B. P., or Liquor FolassBe Arsenitis, IT. S. P. (Fowler's Solution.}
Note. — This official solution does not (renerally contiin arsenit* of potassium ; for the arsenic doPB not decompose the caihonale of potassium, or only after long boiling From concentiatid solutirma carbonic acid gas is more qnitlily eliminated.
Arsenions Acids and other Arsenites. When arsen (AO)dwld s. fit fpth
or soda, arsen t f 1 h ^ th f m lie KH AsO d
NaHjAaOj. B 1 d w th ce f 1 1 f th
salts combines with frs Th Ihtfh
compounds is th t f ly lli 1 1 qnid A ni anhydride {th o- 11 d ac 1) wh d 1 1 w t
yields true ars d [H AaO ) th t f hydi g
ASjO, + 3H,0 = 2H,AsOs
Acid Solution of Arsenic.
Second Synthetical Reaction. — Boil arsenic with dilute hydrochloric acid. Such a solution made with prescribed proportions of acid and water, and containing 4 grains of arsenic {As,,0,) per ounce, forme the Liquor Arsenici By- dr'ochloricus, B. P. (De Valangin's Solution contained a grain and a half per ounce.)
id .y Google
130 THE METALLIC) RADICALS.
Note. — No decomposition occurs in tbjs experiment. The liquid ia Bimplj a flolntion of aisenic in dilute hydrochloric acid. These two solutions may be preserved for analytical operations.
Mem. — The prtictioal student should boU arsenic in water only, and thus have an acid, alkaline, and aqneous solntion for analytical comparison.
Arsenicnm.
Third Synlhetioal Beaation. — Place a grain or less of arsenic at the bottom of a narrow teat-tube, cover it with about half an inch or an inch of email fragments of dry charcoal, and hold the tube, nearly horizontally, in a flame, the mouth being loosely covered by the thumb. At first let the bottom 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 arsenic will sublime, become deoxidized by the charcoal, carbonic oxide being formed, and arsenicum deposited in the cool part of the tube as a, dark mirror-like metallic incrustation.
There is a characteristic odor, resembling garlic, emitted during this operation, probably due to a partially oxidized trace of arseni- cum which escapes from the tube ; for arsenic alone does not give this Odor, neither, it is Said, does arsenicum; moreover, arsenicnm being a freely oxidizable element, its vaporous particles conld scarcely exist in the air in an unoxidized state.
Metallic arsenicum (Arsenicum, V. 8. P.) may be obtained in lai^ quantities by the above process if the operation be conducted in vessels of commensurate siae. But performed with sreat care, in narrow tubes, using not charcoal alone, but black ^usc {a. mixture of charcoal and carbonate of potassium obtained by heatmg acid tar- trate of potassium 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 miiror-liko ring being highly characteristic of arsenicum. Compounds of mercury and antimony, however, give sublimates which may be mistaken for arsenicum.
Arsenic Acid and other Arseniates.
Fourth' Synthetical Reaction. — Boil a grain or two of arsenic with a few drops of nitric acid until red fumes cease to be evolved ; evaporate the solution in a small dish to dryness, to remove excess of nitric acid; dissolve the residue in water : the product is Arsen'ic acid (HjAsOJ.
Arsenic acid, when strongly heated, loses the elements of water, and arsenic anhydride remains (AsjOj).
Arsenic aiihydride readily absorbs water and becomes arsenic acid (HjAsOi). Arsenic acid is readily reduced to arsenious by the
id .y Google
ARSENICUM. 131
action of reducing agents such as aalphurons acid, H,AsO,+H,80, =H3AaO,+H,SO,.
Saltg analogoua to arsenic acid, the arseniate of lijdrogen, are tenned arsemates, and have the general formula B'^AsO,. The am- mouium arseniate ( AiiijH AsOj) may be made Ijy neutralizing- arsenic
acid with ammonia. Arsenic acid ie uaed as an oxidizing agent in
the manufacture of the well-known dye, magenta.
Arsenite and arseniafe 6f sodium are nsed in the cleansing opera- tions of tlie calico-printer.
Fyroarseniate and Arseniate of Sodium. M/ih Synthetical Eeadion. — Fuse a minute fragment of common white arsenic (As^O,) with nitrate of sodium (NaNO,) and dried carbonate of sodium (NajCOa) in a por- celain crucible, and diasolve.the mass in water; solution of arseniate of sodium (NajHAsOJ results.
As.O, + 2NaN0, -(- Na^CO, = Na,Ae,0, + N,0, + 00,
ITie official proportions (B, P.) are 10 of arsenic to 8^ of nitrate of sodiuUi and 5J of dried carbonate, each powdered, the whole well mixed, fased In a crucible at a red heat till effervescence ceases, and the liquid poured out on a slab. The product is pyroaraeniafe of sodium (Na,Aa,0,). Dissolved in water, crystallized, and dried, the salt has the formula NajHAsO,, TH^O (<Sodte Arserdas, B. P.),
Na^AsA + 15n,0 = 2(Na,HAsOi, 7.HiO).
this preparation because the crystallized is < composition. The fresh crystals are represented by tie formula NajHAsO^. 12H,0 (=53.7 ^er cent, of water) ; these soon effloresce and yield a stable salt havmg the formula N"ajHAs04, 7HjO (= 40.4 per cent, of water). To avoid the possible employment of a mixture of these bodies, the invariable anhydrous salt is ofBcially used, constancy in the strength of a powerful preparation being thereby secured.
Arseniate of Iron. Ferrous Arseniate. Sixth Synthetical Reaction. — To solution of arseniate of sodium add a little acetate of sodium and then solution of ferrous sulphate, a precipitate of ferrous arseniate occurs (Fo,2A80.) (Fern Arsenias, B. P.). On the large scale 4 parts of dried arseniate and 3 of acetate dissolved iu 40 of water, mixed with 9 of sulphate in 60 of water, jnay
id .y Google
133 THE METALLIC RADICALS.
be employed. The precipitate shoulrl be collected on a calico filter, washed, squeezed, and dried at a low tempera- ture (100° P.) over a wash-bath to avoid excessive oxidittion.
2Na,HAfiO, + 2NaC,H,0, + 3FeS0, = Fe,2AsO, + 3Na,S0. + 3HC,H,0,.
Sulphaleof Acelicarjid.
The use of the acetate of sodiv,m is to inaure the oeciuTencc of acetic BtAA in Bolution, where otherwise would be free Bulpliuric acid. Sulphuric acid is a solvent of ferrous arseniate ; acetic acid is not. It ia impOBsible to preveat the separation of sulphuric acid, if only ferrous sulphate and arseniate of sodium be employed. At the instant of precipitation ferrooa arsejiiate is white, bat rapidly becomes of a green or greenifih-blue color owing to absorption of osygen and formation of a ferroso-ferric arseaiafe. It is a tasteless amoqjhous powder, soluble in acids.
The Hydride and Sulphides of Arsenioum, and the Arseniles and Arseniates of Copper and of Silver are men- tioned in the following analytical paragraphs : —
(i>) BeacHons having Analytical Interei^t (Tests).
First Analytical Reaction. — Cut or break off portions of the tube containing the sublimate of arsenicura obtained in the third synthetical reaction, put them into a test-tube and heat the bottom of the latter, holding it nearly hori- zontally, and covering the mouth loosely with the Snger or thumb ; the arsenicnm (AeJ will absorb oxygen from the air in the tube, and the resulting arsenious anhydride (As^O,) be deposited on the cool part of the tube in char- acteristic octahedral {Axti; okto, eight ; iSpo, hedra, side) crystals, more or leas perfect.
Microscopic Test. — Prove that the crystals are identical in form with those of common white arsenic, by heating a grain or less of the latter in another test-tube, examining the two sublimates by a good lens or compound microscope.
Notes. — -The production of arscnicum and its subsequent oxidation are test-reactions perhaps not quite so delicate as some that follow, reqniring more materisJ for their satisfactory performance ; yet the form of the crystals is characteristic, no other volatile body being likely to be mistaken for them; and in toxicological cases it is desirable to obtain the arsenicura in a similar state to tliat in which
id .y Google
probably it oi'igiually exerted its effects; the processes alluded to are therefore of considerable importance. Moreover, araenicnm, ready for sublimatioa to crystalline araenic, is easily obtained from eolation by the following reaction :—
Second Analytical Reaction. — Place a tbia piece of cop- per, about a quarter inch wide and half inch long, in a solution of arsenic, acidified by hydrochloric acid, and boil (nitric acid must not be present, or the copper itself will be dissolved) ; arsenieum is deposited on tbc plate in a metallic condition, an equivalent portion of copper going into solution. Poor off the supernatant liquid from the copper, wash the latter once or twice with water, dry the piece of metal by holding in the fingers and passing through a fiame, and finally place it at the bottom of a clean dry narrow teat-tube ; sublime as described in the last reaction, again noticing the form of the resulting crystals
This is commonly known aa Eeinsch's test for arsen um The tube may be reserved for subsequent comparison with an a t on al subhrnato (p. 144).
.Mjie.— Copper itself ftcqnently contains arsenieum, a fa t that may not, perhaps, much trouble an operator so long as he p f m jng experiment in practical chemistry merely for educat al pu poses ; Dut when he engages in the analysis of bodies f inkn wn composition, he most assure himself that neither his apparatus nor materials already contain the element of which he is in search.
The detection of arsemcimt in metallic copper is best accom- plished by distilling a mixture of a few grains of the sample with five or six times ite weight of ferric hydrate or chloride (free from arsenieum) and excess of hydrochlorie acid. The arsenieum is thus volatilized in the form of chloride of arsenieum, and may be condensed in water and detected by sulphuretted hydrogen (5th Analytical Reaction) or Reinsch'a test. The ferric chloride solution is, if neces-
Third Analytical Reaction — Marsh's test — Generate hydrogen in the usual way from water by zinc and sulphu- ric acid, a bottle of about four or six ounces capacity being used, and a funnel-tube and short delivery-tube passing through the cork in the usual manner (described on page 69). Dry the escaping hydrogen (except in rough experiments, when it is unnecessary) by adajiting to the delivery-tube, by a pierced cork, a short piece of wider tubing containing fragments of chloride of calcium. To the opposite end of the drying-tube fit a piece of narrow tubing ten or twelve inches long, made of hard German glass, and having its aperture narrowed by drawing out 13
id .y Google
IH THE METALLIC EABICALS.
in the flame of the blowpipe. When the hydrogen has been escaping at such a rate and for a sufficient number of minutes as to warrant the operator in concluding that all the air originally existing in the bottle has been ex- pelled, set light to the jet, and then pour eight or ten drops of the aqueous solution of arsenic, or three or four drops of the acid or alkaline solution of arsenic, previously pre- pared, into the faiinel-tube, washing the liquid into the generating-bottle with 'a little water. The arsenic is at once reduced to the state of arsenicum, and the latter combines with some of the hydrogen to form hydride of arsenicum or araeniuretted hydrogen gas (AsH,). Imme- diately hold a piece of earthenware or porcelain (the lid of a porcelain crucible, if at hand) in the hydrogen jet at the extremity of the delivery-tube; a brown spot of con- densed arsenicnm is deposited. Collect several of these spots, and retain them for future comparison with anti- monial spots (p. 144).
The separation of arsenicum in the flame is due to the decompo- Bition of the arsenioretfed hydrogen by the heat of combustion. The cool porcelain at once condenses the arsenicum, and thus pre- vents its oxidation to white arsenic, which would otherwise take plaflc at the outer edge of the flame.
Hold a small beakct^or wide test-tube over the flame for a few minutes ; a white fllm of arsenic (AsjOJ Will be slowly deposited, and may be further examined in contrast with a similar antimonial fllm (p. 144).
During these experiments the effect produced by the aisenica! vapors on the color of the hydrogen-flame will have been noticed; they give it a dull livid bluish tint. This is characteristic.
Apply the flame of a gas-lamp to the middle of the hard delivery-tube; the arseniuretted hydrogen, as before, is decomposed by the heat, but the liberated arsenicum (As^) immediately condenses in the cool part of the tube beyond the flame, forming a dark metallic mirror. The tube may be removed and kept for comparison with an antimonial deposit.
Note I. — Zinc, like copper, frequently itself contains arsenicum. When a specimen free from arsenicum is met with, it should be re- served for analytical experiments, or a quantity of guaranteed purity should be purchased of the chemical-apparatus maker. Sulphuric acid is more easily obtained free from arsenic.
Note II. — In delicate and important applications of Marsh's test, magnesium may be substituted for ziuc with safety, a
id .y Google
ARSENIOUM. 135
has not yet been, nor is it likelj to be, fonnd in magnesinm. Mag- nesium in rods is convenient for tliis purpose, and may be obtained from most dealers in chemicals.
Note III. — Araeniuretted hydrogen is decomposed by strong snl- pharic acid ; hence chloride of calcinm is used in drying the gas.
Fourth Analytical Reaction — Fleiimann's test. — Generate hydrogen by heating to near the boiling-point a strong so- lution of caustic soda or potash and some pieces of zinc. Drop into the test-tube a little arsenical solution, and spread over the mouth of the tube a cap of fllter-paper moistened with one drop of solution of nitrate of silver. Again heat the tube, taking care that the liquid itself shall not spirt up on to the cap ;. the arsenic is reduced to arsenicum, the latter uniting with the hydrogen as in Marsh's test ; and the arseniuretted hydrogen passing up through the cap reacts on the nitrate of silver, causing the production of a purplish-black spot.
AsH, + 3H,0 -^ SAgNO, = H^AsO^ + BKNO, -1- 3Ag^
Note. — This reaction is particularly vaiaabie, enabling the ana- lyst to quickly distingnish arsenicnm in the presence of its sister element antimony, which, although it combines with the hydrogen evolTod from dilnte acid and zinc, does not combine with the hydro- gen evolved from Bolntion of alkali aud zinc, and tliei'efore does not give the effect just described.
Distinction between Arsenious and Arsenic combinations.— above festa are those of arsenicnm, whether existing in or arsenic condition, though from the latter the element is not gene- rally ehminated so quicfely as from the former. Of the following reactions, that with nitrat* of silver at once distinguishes arseoions acid and other arsenites from arsenic acid and other arseniates.
Mem. — The exact nature of all thwe analytical reactions will be more fully evident if traced out by diagrams or equations.
Fifth Analytical Reaction. — Through an acidified solu- tion of arsenic pass sulphuretted hydrogen ; a yellow pre- cipitate of sulphide of arsenicum or arsenious sulphide (ASjSa) quickly falls. Add an alkaline hydrate or aulphy- drate to the precipitate, it readily dissolves. The precipi- tate consequently would not be obtained on passing sul- phuretted hydrogen through an alkaline solution of arsenic-
id .yCoOglc
136 THE METALLIC RADICALS.
Note I.— Tho only other metal which gives a yellow sulphide in &a acid solution by action of Eiilphiirett«d hydrogen is cadmrnm ; but this sulphide is insoluhie in alkaline liquids.
Note II. — A trace of sulphide of arBenicum is Bometimra met with in sulphur fdistilled from arsenical pyritee). It may be detected by digestiEg me sulphur in solution of ammonia, filtering, and evapo- rating to dryness ; a yellow residue of sulphide of araenicum is ob- tained if that substance be present.
Sixth Analytical Reaction. — Through ati acidified solu- tion of arsenic acid, or any. other arseniate, pass sulphu- retted hydrogen ; a, yellow precipitate of arsenic sulphide (As^^Sj) slowly falls. This also is soluble in alkaline hy- drates and Bulphydratea.
Chemical Analogy of Sulphur and Oxygen. — The solubility of arsenions and arsenic sulphide in alkaline solutions is good evidence of the close chemical analogy between them and the corresponding oxygen compounds of arsenicum. The potassiuju arsenite and sulph- arsenile, arseniate and solph-arseniate, have the composition repre- sented by the following formula; — -
|
It.ASUj K,AsS, |
±1.,ASU. KjAsS, ; |
|
|
and the cc coinpositi<: |
■rre spending ammonit |
im and sodium salts ha^ |
|
6AmHS + As,Sj 6AmH8 + As,S, |
= 2Am,AsS, -H 3H,S = 2Am,As8, + 3H,S, |
Seventh Analytical Beaction. — To an aqueous solution of arsenic add two or three drops of solution of sulphate of copper, and then cautiously add diluted solution of ammonia, drop by drop, until a green precipitate is ob- tained. The production of this precipitate is character- istic of arsenicum. To a portion of the mixture add an acid ; the precipitate dissolves. To another portion add alkali ; the precipitate dissolves. These two oxperimeots show the advantage of testing a snspected arsenical solu- tion by litmus-paper before applying this reaction; if acid, cautiously adding alkali, if alkaline, adding acid, till neu- trality is obtained. (Or a special copper reagent may be used ; see a note to the Tenth Keaction, p. 131.)
The precipitate is arsenite of copper (Ou"HA303) or Scheelf's Green. More or less pure, or mixed with acetate oi, ooca'Jionally, carbonate of copper, it is very largely used as a pigment undei many names, such as Brunswick Green and Schweinfuith Uroeii, by painters, paper-stainers, and others.
id .y Google
AESBNICtlM. 137
Eighth Analytical Reaction. — Apply the test ji\st de- scribed to a solution of arsenic acid or other arseniate ; a somewhat similar precipitate of arseniate of copper is obtained.
Ninth Analytical Seaction. — Repeat the seventh reaction, substituting nitrate of silver for sulphate of copper: in this case yellow arsenite of silver (AgjAsOa) falls, also soluble in acids and alkalies.
Tenlh Analytical Seaction. — Apply the test to a solution of arsenic aeid or other arseniate ; a cAocoZate-colored pre- cipitate of arseniate of silver (Ag,AsO,} falls.
Copper and Silver Reagents for Arsenicuw.. — The last four reac- tions may be performed with iacreased delicacy and certainty of result, if the copper and silver reagents be previonslj prepared in the following manner : To solution of pure sulphate of copper (about 1 part ill 20 of water) add ammonia uutil the blue precipitate at first formed is nearly all redissolved ; filter and preserve tie liquid as an arseaicum reagent, labelling it nolution of am/monio-sidphate of copper (B. P.). Treat soiution of nitrate of silver (about 1 part in 40) m the same way, and label it solution of ammonio-mtraie of silver (B. P.). The composition of these two salts will be referred to subsecjaently,
Areen^ous and Arsenic Cotnpovm.ds. — While many reagents may be used for the detection of arsenioum, only nitrate of silver, as already stated, will readily indicai* in which state of osidation the arsenicum exists; for the two sulphides and the two copper precipi- tates, though differing in composition, resemble each other in appear- ance, whereas the two silver precipitates differ in color as well as in composition.
Soluble arseniatea also give insoluble arseniates with barium, cal- cium, zinc, and some other metallic solutions.
Antidote. — In cases of poisoning by arsenic or arsenical preparations, the most effective antidote is recently pre- cipitated moist ferric hydrate {Ferri Peroxidum Humidum, B. P.). It is perhaps best administered in the form of a mixture of solution of perchloride of iron {Liquor or Tine- iwra), with carbonate of sodium — two to three ounces of the former to about one ounce of the crystals of the latter. Instead of the carbonate of sodium about a quarter of an ounce of calcined magnesia maybe used. These quantities will render at least 10 grains of araenie insoluble. Emetics should also be given, an<3 the stomach-pump applied as quickly as possible,
The above Btatementa regarding the antidote (br arsenic may be verified by misiflg the various substances together, filtering, and
id .y Google
138 THE METALLIC RAPICALS,
pvovicg tte absence of arsenioum in the filtrate by applying some of the foregoing tests.
Mode of action of the Antidote. — The action of the carbonate of Bodium or the magnesia ia to precipitate ferric hydrate (Fej6E0) — ■ chloride of sodium (NaCl) or raagnraium (MgOL,) being formed, which are harmless, if not beneficial, nnder the circumstanceB. The reaction between the ferric hydrate and the arsenic results in the for- mation of insoluble ferroas araeniate.
2(Pe36HO) + As^Oj = Fe32AsO( + 5HjO + Fe2H0
hjdrale, araeulaLe. hydrale.
As already stated dried ferric hydrate {then "become an oxyhy- drate, PejOjiHO) [Ferri Peroxidwm, Hydratuw,, B, P.) has no action on arsenic. Even the moist rec tly prep d hydrate (FejGHOjooasestoreactwitharBenicasso as t ha h me con- verted into an osyhydrate (FejOjeHO), a h ng h h occurs though the hydrate be" kept under water. A ding t T and H. Smiti this decomposition occurs gradually b t n an reasing ratio ; BO that after four months the power f th m ist m s is re- duced to one-half, and after five mouths to o f th
QUESTIONS AND EXERCISES.
235. In what form does arsenicnm occur in nature ?
236. Describe the characters of white arsenic.
237. Name the official preparations of arscnicum.
238. What proportion of arsenic (As^Oa) is contained ij ^rsenicalis, B. P., and Liquor Arsenici HydrocMoriciis
239. By what method may arsenic he rednced to arsenic 241). Give the formulae of arsenions and atsenic acids.
241. Explain, by diagrams, the reactions which occur in convert ' g arsenic into Arseniate of Sodinm by the process of the British
k;
242. Why is anhydrous instead of crystallized arseniate of sodium employed in the preparation of Liquor Sod<e Arseniatis, B, P. ?
243. In the preparation of Arseniate of Iron from ferrous snlphafe and arseniate of sodium, why is acetate of sodium included 7
244. Describe the manipulations necessary in distinguishing arsenic by its c^stalline form.
245. How is Eeinsch's teat for arseuicum applied, and under what oircumstances may its indications bo fallacious ?
246. Give the details of Marsh's teat for arsenicnm, and the pre- cautions to be observed in its performance. Explain the reactions by diagrams.
247. What peculiar value hsfl Fleitmann's test for arsenicnm ?
248. Describe the oonditioBS under which salphuretted hydrogen becomes a trustworthy test for arsenicnm.
249. How may a trace of sulphide of arsenicijm be detected in sulpliur !
id .y Google
ANTIMONY.
251. How are arsenites disti
252. Mention the best aat explain the process by whicli describe its actioD.
253. What light does the action of .
[ngtiished Irom arseniates ?
idote in cases of poisoning by arsenic,
it may be most quicltly prepared, and
Sy:nbol Sb (stibium). Atomic weight 122.
Source and Uses. — Antimony occurs in nature chiefly as sulphide, SbjSj. The crude or black antimony of pharmacy is this native sulphide freed from earthy impurities by fusion : it has a striated, crystalline, lustrous fracture ; subsequently powdered it forma the grayish-black crystalline Antwwnium ntgrum, B. P., Antiinonii sidpkwetutn, U. 8. P. The metal is easDj obtained from the sul- phide by roasting, and then reducing with charcoal and carbonate of sodium. Metallic antimony is an important constituent of Type- metal, Britannia metal (lea and coffee pots, spoons, etc.), and the best varieties of Pewter. The old pocuia emetica, or everlasting emetic cups, were made of antimony ; wine kept in them for a day or two acquired a variable amount of emetic quality. The metal is not used in making the antimonial preparations of the Fharmaco- pceia, the sulphide alone being, directly or indirectly, employed for this purpose.
Antimony has very close chemipal analogies with arsenicum. Its atom, in the official salts, exerts trivalent activity (e.g., SbOlj), but sometimes it ia quinquivalent (e.g., SbClj).
(a) Reactions having Synthetical Interest. Chloride of Antimony, Antimonious Chloride. First Synthetical Reaction. — Boil half an ounce or lees of sulphide of antimony with four or five times its weight of hydrochloric acid in a dish in a fume-chamber or the open air; aulphnretted hydrogen ia evolved and solution of chloride of antimony, SbClj, obtained;
SbS^ + 6HC1 = SSbCl, -[- 3ES
id .y Google
140 XHE METALLIC RADICALS.
This solution, cleared by subsidence, is what is commrnily known as Butter of amtimony (Liquor Antimonii Chloridi, B. P.), If pnre sulphide has been used in its preparation the liquid is nearly eolorlesB; but mach of that met with in veterinary phannacy ia simply a by-product in tie generation of sulphuretted nydrogen from native BulpEde of antimony and hydrochloric acid, and is more or less brown from the presence of chloride of iron. It not unfrequently darkens in color on keeping ; this is due to absorption of oxygen from the air and converaioc of light-colored ferrous into dark-brown ferric chloride or oxychloride.
True butt^ of antimony (SbOU is obtained on evaporating the above aolulion to a low bulk, and distilling the residue. The butter condenses as a white crystalline seini-tranaparent ma^ in the neck of the retort ; at the close of the operation it may be easily melted and run down in a bottle, which should be subsequently well stoppered.
Pentacidoride of antiino'ny (BhGV^, OT antiraonic chloride, ia a fuming liquid, obtained on passing chlorine over the lower chloride.
OxfcMoride of Antimony. Antimonioos Oxychloride.
Second Synthetical Eeaction. — Pour the soiutioQ of chlo- ride of antimony produced in the last reaction into several ounces of water ; a white precipitate of oxychloride of an- timony (2SbCls, SSbjOj) falls, some chloride of antimony remaining in the supernatant acid liijiiid.
This is the o\Apvlvis Algarothi, pulvia angeUaia vitcE. On Stan ding- uuder water it gradually becomes orystallii
128hCl3 + I5H,0 = 2Sb01„5SbA + 30HC1
Oxide of Antimony. Antimonious Oxide. Well wash the precipitate with water, by decantation (vide p. 81), and add solution of carbonate of sodium; the terchloride remaining with the oxide is thus decomposed, and oxide of antimony (SbjO,) alone remains. This is Antimonii Oxidum, B. P. and U. S. P. It is of a light buff or grayish- white color, insoluble in water, soluble in hydro- chloric acid, fusible at a low red heat. The moist oxide of antimony may be well washed and employed for the next reaction, or dried over a water-bath. At tempera- tures above 212° oxygen is absorbed, and other oxides of antimony formed. The presence of the latter is detected on boiling the powder in solution of acid tartrate of potas- sium, in which oxide of antimony {SbjO^) is soluble, but antimonic anhydride (Sb.Oj) and the so-called antiinonious anhydride (Sb^OJ insoluble.
id .y Google
A higher oxide of antimony (SbjO^), termed antimonic oaide or anhydride, correspondiug with arsenic anhydride, is obtained on do-' composing the pentMhloride by water, or on boiling metallic anti- mony with nitric a«id. The variety obtained from the chloride differa in saturating-power from that obtained from the metal, and is termed metantiffionic acid [niia, meta, beyond).
Tartar Emetic. Third Synthetical Beaction. — Mix the moist oxide of antimony obtained in the previous reaction with about an equal quantity of cream of tartar (6 of the latter to 5 of the dry oxide) and sufficient water to form a paste ; set aside for a day to faeilitate complete combination ; boil the product with water, and filter ; the resulting liquid contains the double tartrate of antimony and potassium (KSbCjHjO,), potassio-tartrate of antimony, tartrated an- timony or tartar emetic (emetic, from i^ta, emeo, I vomit ; tartar from Toprof oj, tartaros, see Index).
H,0
On evaporation the salt is obtained in colorless trans- parent triangu!ar-faeed crystals of the above composition, with a molecule of water of crystallization, forming the Antimonium Tartaratum, B. P. (KSbOC^H^OjjHjO) the Antimonu et PotasKse Tartras, TT. S. P.
The formula for tartar emetic is apparently ineonsistent with the general formula for tartrates (R'E'CjH^O,,) ; this will be subsequently fully explained in connection with Tartaric Acid. The salt appears to be an oxytartrate (KSbOC^Hpa).
Tartar emetic is soluble in water, and slightly so in proof spirit. Dissolved in sherry wine it forms the official Vinum Antimoniale, B. P., and Vinum Antimonii, IT. S. P. It may be externally applied as an ointment, Unguentum An- timonii Tartarati, B. P. { Unguentum Antimonii, U. S. P.).
Sulphurated Antimony. Oxysulpbide of Antimony.
Fourth Synthetical Iteaotion. — Boil a few grains of sulph- ide of antimony with solution of soda (potash, U. S. P.) in a test-tube (or larger quantities in larger -^
id .y Google
142 THE METALLIC RADICALS.
ounces of sulphide to 4j pints of tiie official solution of soda for 2 hours, frequently stirring, and occasionally re- placing water lost by evaporation), and filter; into the filtrate, before cool, stir diluted sulphuric acid until the liquid is slightly acid to test-paper ; a brownish-red pre- cipitate of oxysulphide of antimony, the Antimonium Sul- phuratum, B. P. and "U. S, P., falls ; filter, wash, and dry over a water-bath. It is a mixture of sulphide of anti- mony (Sb,S,) with a small and variable amount of oxide (Sb„Oi,). The oxide results from the double decomposition of sulphide of antimony and soda (Antimonii Oxysul- phuratum).
The United States Pharraacopceia in another preparation orders carbonate of sodium instead of the caustic alkali, and directs that only that precipitate be retained which separates from the alkaline liquid on cooling.
Ifa small qnantity of snlphurbe boiled with the sulphide of antimony in solution of soda, the precipitate on the addition of sulphuric acid will be bright orange-red, on account of the presence of a higher sulphide having a yellow color (Sb^Sj).
There are some of the many rarieties of min&ral kermes, so called from their similarity iii color to the insect kermes. Kermes is the name, now obsolete, of the Coccus llicis, a sort of cochineal-insect, full of reddieh juice, and used for dyeing from the earliest times.
Explanation of process. — The sulphides of antimony, like those of arsenicum, unite with sulphides of metals to form solnble salts. In the hot solutions of these salts sulphide and oxide of antimony are soluble, and are reprecipitated in an indefinite state «f combiDa- tioD, partially, oo cooliuff, or wholly on the addition of acid. The acid also decomposes the Bulphur-aalt itself witli precipitation of orange sulphide of antimony. The acid is added to the liquid he- fore much oxysulphide has deposited (that is, before the solution is cool), in order to insure uniformity of product.
b O5 -I- 3H,0
2Na3Sb83 + 3HjS0j = SNa^SO, ■
enlph-B.ntimonita Sulpliiirlc Sulphaleof ... . __.,_..
otsodium. acid. eodiDm. antimDnT. h^dro]
The oside and sulphide mentioned in these equations, together with excess of sulphide of antimony dissolved by the alkaline liquid and reprecipitated by the acid, form the SulphuToied Antimony of the Pharmacopfeias, " an orange-red powder, readily dissolved by caustic soda, also by hydrochloric acid with the evolution of sul- phuretted hydrogen and the separation of a little sulphur." Its anti-
id .yCoOglc
mony ia detected by diasolving the precipitate in hydrocliloric acid, or in solution of acid tartrate of potassium, and paasing sulplinrctted hydrogen through the liquid, as descrihed iu the first analytical
These ftmr synthetical reactions illnstrate the official processes for the resjwctiTe substances. The solution of chloride of antimony is only used in the preparation of oxide ; the oxide, besides its use ID the preparation of tartar emetic, ia mixed with twice its weight of phosphate of calcium (purified bone-earth) to form PiUvis Anti- moniahs, B. P.
The sidphides and hydride of antimony are incidentally men- tioned in the following analytical paragraphs.
(6) Reactions having Analytical Interest (Tests).
First Analytical Reaction. — Through an acidified aiiti- raonial solution pass sulphuretted hydrogen ; an orange precipitate of amorphous sulphide of antimony falls. It has the same composition as the crystalline black sulphide (SbgSg), into which, indeed, it is quickly converted by heat. Like sulphide of arsenicum, it is soluble in alkaline solutcone.
A higher sulphide of antimony (Sb^SJ corresponding to the higher sulphide of arsenicum, exists. It is formed on passing sulphuretted hydrogen through an acidified eolu- tion of the higher chloride (SbOlj), or on boiling black sulphide of antimony and sulphur with an alkali, and de- composing the resulting filtered liquid by an acid.
Note. — The arsenions and antimonious compounds only are cm- ployed in medicine. The arseniatcs and antimoniates are sometimes useful in analysis, and the antimonie chloride in chemical research. The higher compounds of both elements are noticed herechiefly to draw attention to the close analogy existing between arsenicum and antimony, an analogy carried out m the numerous other compounds of these elements.
Second Analytical Reaction. — Dilute two or three drops of the solution of chloride of antimony with water; a pre- cipitate of oxychioride occurs, the formation of which has been explained under the similar synthetical reaction. The occurrence of this precipitate distinguishes antimony ft'om arsenicum, but is a reaction that cannot be fully relied upon in analysis, because requiring the presence of too much material and the observance of too many con- ditions. Add a sufficient quantity of hydrochloric acid to
id .y Google
lii THE METALLIC RADICALS.
dissolve the precipitate, and boil a piece of copper in the solution as directed in the corresponding test for arseni- CMca (vide page 133J; antimony is deposited on the copper. Wash, dry, and heat the copper in a test-tube as before ; the antimony, like the araenicum, is volatilized off the copper and condenses on the side of the tube as white oxide, bnt the sublimate, from its low degree of volatility, condenses close to the copper, and, moreover, is destitute of crystalline character, is amorphous (a, a, without ; ftopij>ij, morphs, shape).
Shake out the copper and boil water in the tube for several minutes. Do the same with the arsenical subli- mate similarly obtained. The deposit of arsenic slowly dissolves, and may be recognized in the solution by ammonio-nitrate of silver; the antimonial sublimate is insoluble.
Third Analytical Reaction. — Perform the experiments described under Marsh's test for arsentcum (pp. 133-4), carefully observing all the details there mentioned, but using a few drops of solution of chloride of antimoBy or tartar emetic instead of the arsenical solution. Anti- moniuretted hydrogen, or hydride of antimony (SbHa), is formed and decomposed in the same way as arseniuretted hydrogen.
To one of the arsenicum spots on the porcelain lid (p. 134) add a drop of solution of "chloride of lime" (bleach- ing-powder) ; it quickly dissolves. Do the same with an antimony spot ; it is unaffected.
Heat more quicklj causes the volatilization of an arsenicum thnn an antimony spot; sulphydrate of ammoninm more readily diasolyea the antimODj than the arsenicum.
Boil water for several minutes in the beaker or wide test-tube containing the arsenious sublimate (page 144); it slowly dissolves and may be recognized in the solution by the yellow precipitate given on the addition of solution of ammonio-nitrate of silver. The antimonial sublimate, similarly treated, gives no corresponding reaction.
Pass a slow current of sulphuretted hydrogen through the delivery-tube removed from the hydrogen-apparatus (page 134), and, when the air may be considered to have been expelled from the tube, gently heat that portion con- taining the deposit of arsenicum ; the latter will be con- verted into a yellow sublimate of sulphide of arsenicum. Remove the tube from the sulphuretted-hydrogen appa-
id.y Google
ANTIMONY. 145
ratiia, aiid I'epeat the experiment witli a similar antimony deposit ; it is converted into orange sulphide of antimony, wliicb, moreover, owing to inferior volatility, condenses nearer to the flame than sulphide of arsenicum.
Pass dry hydrochloric acid gas through the two de- livery-tubes. This is accomplished by adapting iirst one tube and then the other by a cork to a test-tube containing a few lumps of common salt, on which a little sulphuric acid is poured during the momentary removal of the cork. The sulphide of antimony dissolves and disappears ; the sulphide of arsenicum is unaffected.
Tliorough perception of the chemistry of arsernicum and anti- mony mil be obtained on constructing equations or diagrams descriptive of each of tlie foregoing reactions.
Antidote. — The introduction of poisonous doses of anti- monials into the stomach is fortunately quickly followed by vomiting. If vomiting has not occurred, or apparently to an insufflcieot extent, any form of tannic acid may be administered (infusion of tea, nntgalla, cinchona, oak-bark, or other astringent solutions or tinctures), an insoluble tannate of antimony being formed, and absorption of the poison consequently somewhat retarded. The stomach- pump must be as quickly as possible applied.
Kecently precipitated moist ferric hydrate is also, accord- ing to T. and H. Smith, a perfect absorbent of antimony from its solutions, the chemical actions being probably, they say, similar to that which takes place between ferric hydrate and arsenioua anhydride. It may be given in the form of a mixture of perchloride of iron with either car- bonate of sodium or magnesia.
These statements may be verified by mixing together the various substances, filtering, and testing the filtrate for antimony in the
DIKECTIONS FOR APPLYING THE POREGOINO REACTIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION OP SALTS OF OBTE Of THE ELEMENTS ARSENICUM AND ANTIMONY.
Acidify the liquid with hydrochloric acid, and pass through it sulphuretted hydrogen : —
A yellow precipitate indicates arsenicnm.
An orange precipitate indicates antimony.
The result may be confirmed by the application of other tests.
13
id .y Google
146 THE METALLIC, RADICALS.
DIRECTIONS FOR APPLYING THE POREOOING ;
THE ANA1.VSI8 OF AN AQUEOUS SOLUTION OE SALTS OF BOTH ARSENICUM AND ANTIMONY,
Acidify a email portion of the liqaid with bydrochloric acid, and pass through it sulphuretted hydrogen.
Note I. If the precipitate by sulphuretted hydrogen is unmis- takably orange, antimony may be put down as present, and arseiii- cnm only further sought by the application of Pleitmana'a test to the solnfion of the sulphides iu aqua regia* freed from sulphur by boiling, or, better, to the original solution.
Note II.- Sulphide of antimony is far less readily soluble than sul-
Sihide pf arsenieum in solntion of carbonate of ammoniam. But this act possesses limited analytical value ; for the color of the sulphides is already snffioient t« distinguish the one from the other when they are unmixed; and when mixed, much sulphide of antimony will prevent a little sulphide of arsenieum from being dissolved by the alkaline carbonate, while mnch sulphide of arsenieum will carry a little sulphide of antimony into the solution. When tie proportbns are, apparently, from the color of the precipitate, less wide, sotntion of carbonate of ammonium will be found useful in roughly separating the one sulphide Irom the other. On fllterina; and neutralizing the alkaline solution by an acid, the yellow sulphide of arsenieum is repre- cipitated. The orange sulphide of antimony will remain on tho filter. Note III. Solution of bisulphate of potassium is said by Wohler to be a good reagent for separating the sulphides of arsenieum and antimony, the former being soluble, the latter inaolnble in the liquid. Noti IV. If the precipitate by sulphuretted hydrogen is unmis- takably yellow, arsenieum may be put down as present, and any antimony detected by one of the following processes. These two
Erocessee are rather long, and require much care in their performance, ut are indispensable, because at present we have no simple test for a small quantity of antimony in much arsenieum corresponding with Fleitmann's test for a small quantity of arsenieum in much antimony. First process. — Generate hydrogen and pass it through a small wash-bottle containing solution of acetate of lead, to free the gas from any trace of sulphuretted hydrogen it may possess, and then through a dilute solution of nitrate of silver contained in a test-tube. When the appa- ratus is in good working order, pour into the generating- bottle the 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 nitrate- of-silver tube ; arsenieum, if present, will be found in the solution in the state of arsenious acid, AbH. + SKfi + 6AgISrO, = H,AsO, + 6HN0, + 3Ag,;
* Aqua regia is
id, Google
ARSENICUM AND ANTIMONY, 147
while antimony, if present, will be found in the black precipitate that has fallen, according to the following equation : —
SbH, + SAgNO, = SbAg, + 3HN0,. The arseiiious radical may be detected in the clear, filtered, supernatantliquid,whichstillcoDtaiii8niiichiiitrateofailver, by cautiously neutralizing with a very dilute solution of ammoma, or by adding a few drops of solution of ammonio- nitrate of silver, yellow arsenite of silver being produced, The antimony may be detected by wasiiing the black pre- cipitate, boiling it in an open dish with solution of tartaric acid, filtering, acidulating with hydrochloric acid, and passing sulphuretted hydrogen throngh the solution — the orange sulphide of antimony being precipitated (Hofmann). Second process. — Obtain the metallic deposit in the mid- dle of the delivery-tube as already described under Marsh's test. Act on the deposit by sulphuretted hydrogen gas, and then by hydrochloric acid gas, as detailed in the third analytical i-eaction of antimony (p. 144). If both arseui- eum and antimony are present, the deposit, after the action of sulphnrctted hydrogen, will be found to be of two colors, the yellow sulphide of arstenieum being usually further removed from the heated portion of the tube than the orange sulphide of antimony. Moreover, subsequent action of hydrochloric acid gas causes disappearance of the antimonial deposit, which is converted into chloride of antimony and carried off in the stream of gas.
The chief objection to this process is the liahility of the operator mistaking sulphur, deposited from the snlnliaretted hydrogen gas by heat, for sulphide of arseDicmn. But tne presence or absence of arBenicum is easily confirraed hy applying Pleitmann's test to the original BolTition, wliile the process la most useful for the detection of a small quantity of salt of antimony when mixed with much arae- nical com pounds.
The laboratory student may now proceed to the analysis of aqueona solutions of salts of any of the metalLio elements hitherto considered. The method followed may be that for the separation of the previous three groups, sulphuretted hydrogen being first passed throngh the solution to throw out arsenicum and antimony. The whole scheme of analysis is given on the nest page. Three or four solutions should be examined before proceeding t* the last group of metals.
Learners who have no opportunity of working at practical analysis will gain much knowledge by endeavoring not to remember, but to understand these methods of separating elements from each other in a solution containing several compoOnda.
id .y Google
THE METALLIC 1
|
=.W^ 1 |
|||||
|
."rf |
|||||
|
i:Z 3. |
|||||
|
-:^°% |
§ll |
||||
|
as |
|||||
|
■p" |
|||||
|
1 |
2^1 |
^ |
2 |
||
|
"3 |
■3 =4 .S 0 |
la |
|||
|
iss |
S»_SM |
-3 |
|||
|
i1 |
■U |
||||
|
■< |
5 |
||||
|
N^' |
fu |
||||
|
H a |
* ^ Si" |
^ £ |
|||
|
cjH |
"Sl |
^-S |
|||
|
P^TS |
,, -'® |
m^ |
|||
|
5 |
3g |
||||
|
* .5W |
1 |
i2^ |
i^ |
||
|
^11 |
1 UMzi |
||||
|
SZ |
'§ r^.g'-B ^-S |
||||
|
fe:M |
Fm « 0 ^^ |
||||
|
•i:?'! |
|||||
|
S-^z-c |
|||||
|
^gw g |
|||||
|
-g^-gfg § «3 |
|||||
|
-JdlP |
|||||
|
S|l|| |
Hoa,d, Google
QUESTIONS AND EXERCISES.
254. What ia the compoaition and source of tlio Black Antiinony of pharmacy ?
255. In what alloys is metallic antimony a cliaracteristic in- gredient?
256. What is the quantivalence of antimony as far aa indicated by tlie formula of the ofBoial preparations ?
257. Bj a diagram show how " Butter of Antimony" is prepared.
258. write out equations or diagrams expressive of the reactions which occur in converting chloride of antimony into oxide.
259. What is tie formula of Tartar Emetic ?
260. Explain the ofHcial process for the preparation of Oxyaul- phide of Antimony (AtliimoniiMn Svlphuratum, B. P.) by aid of diagrams.
261. Give a comparative statement of the teats for antimony.
262. How is antimony detected in the presence of £
263. How may arsenicum and iron be distinguished analytically?
264. Deacribe a method by which antimony, magnesium, and iron may be separated from each other.
265. Draw out an analytical chart for the examination of an aqueous liquid containing salts of arsenicum, zinc, calcium, and
COPPER, MERCURY, LEAD, SILVER.
These metala, like arsenicum and antimony, are precipitated from acidified solutions by sulphuretted hydrogen, in the form of sulphides ; but the snlnhides, nnlike those of arsenicum and antimony, are in- soluble in sflkalies. The atom of copper is usually bivalent, Ou" ; mercm'y bivalent in the mercuric salts, Hg", and univalent in tho mercurooa salts, Hg' ; lead sometimea quadrivalent, Pb"", but generally exerting only bivalent activity, Pb" ; and silver univalent, Ag'.
COPPER.
Symbol Ou. Atomic weight 63.5,
Source. — The commooeat ore of this metal is copper pyrites, a double sulphide of copper and iron, raised in Cornwall ; Australia and Enssia supply malachite, a mixed carbonate and hydrate ; much ore is also imported from South America. It is smelt«d in enor- mous quantities at Swansea, South Wales, a locality peculiarly fitted for the operation on account of ita proximity to the coal-fields, and its position as a sea-coast town—these advantages at ail times ing cheap fuel and ireightage to the different metallurgical
13*
id .y Google
150 THE METALLIC RADICALS.
Alchemy. — The alchemists termed this metai V&mis, perhaps on account of the beauty of its lustre, and gave it the Bjmbol ^, a compound hieroglyphic indicating that they thought it a mixture of gold Q and a certain hypothetical substance called acrimony t^i the corrosive nature of which was symbolized by the points of a Maltese cross. To this day the blue Bhow-bottle in the shop-window of the pharmacist is occasionally ornamented by such a symbol, in- dicative, possibly, of the fact that the blue liquid in the vessel is a preparation of copper.
CoMioje.— The material of British copper coinage is bow a bronze mixture composed in 100 parts by weight of 95 copper, 4 tin, and 1 zinc, tie same as in the copper coinage of France. The penny ia coined at the rate of 48 pence in one pound avoli-dnpois, of 7000 grains, or 4S3.6 grammes ; the halfpenny at 80 in the pound avoirdu- pois, and the farOiing at 160. British copper pence are a legal tender in payments to the amount of Is. ; half-pence and farthings tfl the amount of %d.
Metallic Copper {Ouprwm, B.P.) in the form of fine wire, about No. 25, is used in preparing Spvritus jStkeris Nitrosi, B. P. Cop- per Foil, B. P., ia "pure metallic copper, thin and bright"
Qwaidivalence. — Copper forms two classes of salts ; in one the atom is bivalent (Ou"), ill the other exerts univalent activity (Ouj"). The former are of primary importance, the latter being for the moat part unstable and wanting in technical interest. Their compounds are distinguished as cupric and cuprous ; but those of the higher class only have general interest, and will be almost exclusively alluded to in the following paragraphs. Cuprous iodide (Cujij) wiD subsequently be referred to as a convenient form in which to remove iodine from solution, and the formation of cuprous oxide (OujO), under given circumstances, as an indicator of the presence or sugar
Reactions having (a) Sitnthetical and (b) Analytical
Interest.
(a) Synihelical Reactions.
The formation of the following salts includes the only synthetical copper-reactions having any medical or phar- maceutical uiterest: 1, cupric oxide, the blacfe oxide of copper, by heating a piece of copper to low redness on a piece of earthenware in an open fire ; 2, cupric sulphate, the common sulphate of copper, by boiling blaob oxide of copper and about an equal weight of sulphuric acid in ■water, filtering, and setting aside the solution so that crys- tals may form on cooling ; and, 3, the preparation of solu- tion of am monio- sulphate of copper (see p. 153 ; also p. 13T).
id .y Google
COPPEH. 101
Cu„ + 0, = 2CuO. CuO + H,SO, = CuSO, + H,0
Cupric Solpbarie Cupric Water.
Slide. aeid. gnlpbate.
Sulphate of_ Copper ( Cupn Sulphas, B. P. and V. S. P.) (OuSO,, 5H,0J, blue viirioffhltiesioTie, or caprtc sulphate, is the only copper salt of much importance in Pharmacy, It is a by-product in silTer- refining (2AgjSO.+CTi^2CTiSO^+2Agj). It is also fomed by roasting copper pyrit«B, In the latter operation the sulphide of iron and sulphide of copper are oxidized to sulphates ; but the low red heat employed decomposes the sulphate of iron, while the sulphate of copper is unaffected ; it is purified by crystallization from a hot aqueons solution, though frequently much sulphate of iron remains in the crystals. Sulphate of copper results on dissolving in dilated sulphuric acid the black oxide (CuO) obtained in annexing copper plates ; it may also be prepared by boiling copper with three times its weight of sulphuric acid (2HjSO,+ Cu=CuS04+SOi42HjO), diluting, filtering, evaporating, and crystallizing.
Anhydrous Sulphate of_ Oopjier (CuSO,), is a yellowish- white powder prepared by depriving the ordinary blue crystals of sulphate of copper of their water of cryatallizatiou by eiposing to a tempe- rature of about 400° F. It is used in testing alcohol and similar liquids for water, becoming blue if the latter be present.
Verdigris (from verde^rts, 8p.), green-gray, is a Subacetate ( Cw- pri Subaceias, F. S. P.) or Oxyacetate of Copper (B. P.) (0u,02C, HjOj), obtained by exposing alternate layers of copper and ferment- ing refuse grape-husks te the action of air. Di^sted with twice its weight of aoetie acid and a little water, the mixture being evapo- rated to dryness and the residue dissolved in water, it forms the offi- cial Solution of Acetate of Copper (Cu20jH30,).
The modes of fonning cwnc sulphide, hydrate, oxide, ferrocy- anide, and arserdte, as well as the precipitation of metallic copper, are incidentally alluded to in the following analytical paragraphs.
(6) Reactions having Analytical Interest {Tests).
First Analytical Reaction. — Pass sulpliuretted hydrogen through an acidified solution of a copper salt (sulphate, fof example) ; black cnpric salphide (CuS) falls.
Second Analytical Beaction.—.Add sulphydrate of am- monium to an aqueous copper solution ; cupric sulphide is again precipitated, insoluble in excess.
Note. — Cupric sulphide is not altogether insoluble in sulphydrate "'■ ---—11 if free ammonia or mufii ammoniacal salt be present:
it is quite insoluble in the fixed alkaline sulphides.
Third Analytical Reaction. — Immerse a piece of ii steel, such as tlie point of a penknife or a piece of w
id .y Google
153 THE METALLIC RADICALS.
a few dropa of a copper solution ; the copper is depositerl, of characteristic color, an equivaient quantity of iron d; into solution.
By this reaction copper may be recovered on the large scale from waste solntiona, old hoop or other scrap iron being thrown iuto the liquors.
Fourth Analytical Reaction. — Add ammonia to a ciipric solution ; ciipric hydrate (CuSHO) of a light-blue color is precipitated. Add excess of ammonia ; the precipitate is rediasolved, forming a blue solution of nmmonio-salt of copi>er, so deep in color as to render ammonia an exceed- ingly delicate test for this metal.
An ammonio-salplittte of copper may be obtained in large- crystals by adding strongest solution of aramooia to powdered sulphate of copper nntil the salt is dissolyed, placing ihe liqnid in a test-gloss or cylinder, cautiously pouring in twice its volume of strong alcohol or methylated spirit, taking care that the liquids do not hecome mixed, tying over the resse! with bladder, and setting aside for some weeks in a cool place, ^ Wittstein.) The constitution of anunonio^ulphate and other ammonio-salta of copper and corresponding salts of silver will be alluded to in connection with "white precipitate," the ofBcial " ammooiated mercury."
Cuprum Ammomat-am, V. S. P., is an ammonio-aalphate of cop- per prepared by rubbing together sulphate of copper and carbonate of ammonium nntil effervescence ceases, and drying the product.
Fifffi Analytical Reaction. — Add solution of potasb or soda to a cupric solution ; cupric bydrate (Cu2H0) is pre- cipitated, insoluble in excess. Boil the mixture in the test-tube; the hydrate is decomposed, losing the elements of water, and becoming the black anhydrous oxide (CuO).
Sixth Analytical Reaction. — Add solution of ferrocyanide of potassium (K,Pcy} to an aqueous cupric solution ; a red- dish-brown precipitate of cupric ferrocyanide (Cn^Fcy) falls. This also is a delicate test for copper.
Seventh Analytical Reaction.— To a cupric solution add solution of arsenic, and cautiously neutralize with alkali ; green cupric arsenite (CuHAsOa) falls.
A?bie.— This precipitate has been already mentioned under arseni-
um salt is thas a test for copper, as a copper salt
a remark that may obviously be extended to most
13 ; for the body acted •upon ckaracteristieally by
d a test for tlie reagent as the reagent is for it ;
reagent when the other body is the object of
id, Google
MERGUBY. 153
Antidotes.— In cases of poisoning by compounds of cop- per, iron filings should be administered, the action of which has just been explained (see third analytical reaction). Ferrocyanide of potaseinm may also be given (see sixth analytical reaction). Albnmen forms, with copper, a com- pound insoluble in water ; hence raw eggs should be swal- lowed, vomiting being induced or the stomach-pnmp applied as speedilj' as possible.
QUESTIONS AND EXERCISES.
266. What are tlio relations of copper, mercury, lead, and silver to each otlier and to arsenicum and antimony?
267. Name the sources of copper.
268. "What proportion of copper is contained ■ in English and French " copper" coins ?
269. Give oiagrams showing how Sulphate of Copper is prepared on the small and large scales.
270. Worlt out a sum showing how much Cijstailized Sulphate of Copper may be obtained from 100 parts of sulphide? — Ans. 26U.
271. How may Oxide of Copper be prepared ?
272. Mention the formula of Verdigris.
273. Name a good clinical teat for copper.
274. What is the analytical position of copper ?
275. Mention the chief teats for copper.
276. How may copper be separated from arsenicum ?
277. Why is finely divided u^n an effective antidote in cases of poisoning by copper?
MERCURY.
Symbol Hg. Atomic weight 200. Molecular weight 200 {not double the atomic weight).
^OKJ-ce.— Mercury occurs in nature as sulphide (HgS), forming the ore cinnabar (an Indian name expressive of something red), and is obtained fi-om Spain, California, Eastern Hungary, China, Japan, and Peru,
PTeparation. — The metal is sejiarated by roasting off the sulphur and tiien distilling, or distilling with lime, which combines with and retains the sulphur.
Properties. — Mercnry (Hpdrargynan, B. P. and TJ. S. P.) is a silver-white lustrous metal, liquid at common temperature. It boils at 6620 p., and at —40° F. solidifies to a malleable mass of octohedral
id .y Google
154 THE METALLIC HADICALS.
crystals. When quite ft'eefrom otlier metals it does not tamish, and its globules roll freely over a sheet of white paper without leaving any streak or losing their special form.
Medicmai Compoimds. — The componnds of mercury nsed in medicine are all obtained from the metal. The metal itself, nibbed with chalk or with confection of roses and powdered liqnorice-root, or with lard and snet, until globules are not visible to the immded eye, is often used in medicine. The preparations are : the Hydrar- gyrum cum Greta, B. P. and U. 9. P., or " Gray Powder;" JVliiIa Hydrargyri, B. P. and U. 8. P., or " Blue Pill ;" and Vngv,enivmi ffydrcM-gyri, B. P. and U. S. P., or " Blue Ointment." Tlere are also a Compound Ointment, a Plaster of Mercury, a Plaster of Ammoniacnm and Mercury, a Liniment, and a Suppository. Their therapeutic effects are probably due to the 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 oxidos varies ac- cording to the age of the specimen.
Mercurons and Mercuric Compounds J— Mffrcxay combines with other elemeote and radicals in two proportions ; those componnds in which the other, acidulons, radicals are in the lesser amonut are termed mercurous, the higher being mercitric. Thus, calomel (HgtJl)* is mercurons chloride, while corrosive sublimate (HgOl,) is mercnrie chloride. In every pair of mercury compounds the mercu- ric contains twice as much complementary radical, in proportion to the mercury, as the mercurous. .
Note on Nomenclature.— 1)\^ remarks made concerning the two classes of iron salts, ferrous and ferric fp. 106), apply ia the main to the two series of mercviry salts. The latter are systematically dis- tinguished in most modem works by the terms mercurous and mer- curic. In the British and United States Pharmacopceias, however, which includes only a few in comparison with the whole number of mercury salts, older and more strongly contrasted names arc em- ployed, thus ;—
Systematio names. OEBoial names.
Mercurous iodide .... Green iodide of mercury.
Mercuric iodide Eed iodide of mercury.
Mercurous nitrate .... ¥fot mentioned in B. P.
Mercuric nitrate .... Nitrate of mercury.
Mercurous sulphate . . . Not mentioned in B. P.
Mercuric sulphate , , . . Sulphate of mercury.
Mercurous chloride . . . Subchloride of mercury.
Mercuric chloride .... Perohloride of mercury.
Mercurous oxide .... Black oxide of mercury.
Mercuric oxide Eed oxide of mercury.
Specific Gravity. — Mercury is 13.6 times as heavy aa water. Amalgams. — The compound formed in fusing metals together ia
* The specific gravity of the vapor of calomel, and ihe fact that the salt ia not deeompoEed at the temperature at which its speoitio gravity is taken, ahow that the formula of calomel is HgCl, and not HgjCIj.
id .y Google
usually termed an alloy (ad and ligo, to bind) ; but if mercury is a coQstituent, an amalgam, (iJii\ay[ia, malagma, from /^aXanrsi, ma- laso, to soften, the presence of mercury lowering the melting point of suet a mixture).
(a) Synthetical Reactions. The Two Iodides. Mrsl Synthetical Meaction — Rub together a small quan- tity of mercury and iodine, controlling the rapidity of combi- nation by adding a few drops of spirit of wine, which, by evaporation, carries off heat, .and tlius keeps down tem- perature. The product of either mercuric iodide, mercurous iodide, or a mixture of the two, as well as mercury or iodine if excess of either has been employed. If the two elements have been previously weighed in single atomic proportions, 200 of mercury to 12Y of iodine (about 8to 5, or 1 ouace of mercury to 218 grains of iodine), the mer- curoua or green iodide results Hgl {Hydrargyri lodidum Viride, B. P. and U. S. P.) ; if in the proportion of one atom of mercury to two atoms of iodine {200 to twice 12Y, or about 4 to 5), the mercuric or red iodide, Hgl^, results, an iodide that is also official, but made in another way (vide p. 163).
Mercurons iodide is decomposed slowly by light, and quickly by heat, into mercuric iodide and mercury. Mercuric iodide occurring as an impurity io mercurous iodide may be detected by digesting in ether (in which mercurous iodide is insoluble), filtering and evapo- rating to dryness; mercuric iodide remains. Mercuric iodide is stable, and may be sublimed in scarlet crystals without decompo- sition. (For details of the method by which a specimen of the crystals may be obtained, and the precautions to be observed, vide " corrosive sublimate,' p. 158.)
Relation of Mercii/nc Iodide to LdgM. — In condensing, mercuric iodide is at first yellow, afterwards acqniring its characteristic scar- let color. This may be shown by smearing or rubbing a sheet of white paper with the red iodide, and tlien holding the sheet before a fire or over a flame for a few seconds. As soon as the paper be- comes hot the red instantly changes to yellow, and the salt does not quickly regain its red color, even when cold, if the paper is carefully handled. But if a mark be made across the sheet by anything at hand, or the salt be pressed or rubbed in any way, the portions touched immediately return to the scarlet condition. According to Warington, this change is consequent upon rhomboidal crystals being
id .y Google
156 THE METALLIC RADICALS.
converted into octahedra with a sqaare base, and will serve as an exuellent illustration of the inflaence of physical structure in causing color. The yellow modification so acts on the rays of white light shining on its particles as to absorh the violet aod reflect the com- plementary hne, the yellow, which, entering the eye of the ohserver, strikes hia retina, and thus conveys to the brain the impression of yellowness; and the red modification, though actually the same chemical auhatance, is sufBcieatly different in the structure of its par- ticles to absorb the green constituent of white light and reflect the complementary ray, the red.
lUuBlraiionoftKe Gh&micallaw of Multi-pie Proportions [p. 36). — Applying the atomic theory to the above iodides, it will at onco bo apparent why mercury and iodine should combine in the propor- tion of 200 of mercnry with either 12T or 254 of iodine, and not with any intermediate quantity. For it is part of that theory that masKes are composed of atoms, and that atoms are indivisible ; and that the weight of the atom of mercury is to that of iodine as 200 is to 127, Mercury and iodine can only combine, therefore, in atomic propor- tions, atom to atom {which is the same as 200 to 127), or one atom to two atoms (which is the same as 200 to 254). To attempt to combine them in any intermediate proportion would be useless, a mere mixture of the two iodides would result A higher proportion of mercury than 200 to 127 of iodine gives hut a mixture of mercn- rons iodide and mercnry; a higher proportion of iodine than 254 to 200 of mercury gives out a mixture of mercuric iodide and iodine. Or, for example, 200 grains of mercury mixed with, say, 200 of iodine would yield 139 grains of meronrons iodide, and 261 grains of mer- curic iodide; for file 200 grains of mercury uniting with 127 grains of the iodine giTes, for the moment, 327 grains of mercurons iodide and 73 grains of iodine still free. The 73 grains of iodine will im- mediately unite with 188 grains of. the mercurons iodide (for if 127 of I require 327 of Hgl to form Hgl,, 73 will require 188), and form 261 grains of mercuric iodide, diminishing the 327 grains of mercu- rons iodide to 139 grains.
The two Nitrates.
Second Synthetical Seaciion.^-M.ix a little nitric acid in a test-tube with four or five times its bulk of water, add a amall globule of mercury, and set the tube aside for a few hours, in a cool place; solution of mercurous nitrate (HgNO,) will be formed, and nitric oxide (NO) evolved. The solution may be retained for subsequent analytical operations.
Hg, + 4HN0, = 3HgN0, + 2H,0 + NO.
Third Synthetical Eeaction. — Place mercury in strong nitric acid, and warm the mixture; mercuric nitrate is formed, and wiU be deposited in crystals as the solution cools. Retain the product for a subsequent experiment.
id .y Google
c nitraies vary somewliat in composition, according to the proportiou, strength, and temperature of the acid used in their formation, A mercaric uiti'ate m&y bo obtained having; the formnla Hff2NOs.
Hg, + SHNO3 = 3(Hg2KOJ + 2N0 + 4H,0
Mercuric OKynitrates. — Prom the normal mercuric nitrate several Dxyiiitrat«s may be obtained. Thus on merely evaporating a solu- tion of mercuric nitrate, and cooling, crystals having the formula HgjOjSNOj are deposited. . The latter, by washing with cold water, yield a yellow pulverulent oxynitrate, Hgj0j4N0a : mixed with lard, this has soraetiiues been used as an ointinent. Boiled in water, the yellow gives a brichred oxyaitrate, Hg8052NO,.
The Fharmacoposial preparatioua of mercuric nitrate are Liquor Hydrargyri Ni^atis Acidus, B. P. [sp. gr. 2.246 ; D. S. P., sp. gr. 2.165) and Unguonttm, Rydrargyn Nttratis, B. P. and U, S. P. The former (B. P.J ia made by placing four ounces of mercury in five fiuidounces of aitnc acid diluted with an ounce and a half of water, and, when the metal is dissolved, boiling gently for fifteen sunutes.
The Two Sulphates. Fourth Synthetical Reaction — Boil two or tliree grains of mercury with a few drops of strong sulphuric acid in a test-tube; stiJphuroua acid gas (SO,) is evolved, and mer- curic sulphate {Hydrargyri Sulphas, B. P.) (HgSOj) re- sults— a white heavy crystalline powder.
Hg + 2H,S0. = HgSO^ + SO, + 2H^0
Between two and three ounces of mercuric sulphate may be prepared from a fluidvachm of mercury and a fluidounce of sulphuric acid boiled together in a small dish. These are the official proportions. The operation is completed and any excess of acid removed by evaporating the mix- ture of metal and acid to dryness, either in the open air or in a fume-chamber, sulphuric vapors being excessively irri- tating to the mucons membrane of the nose and throat ; dry crystalline mercuric sulphate remains. If residual particles of mercury are observed, the mass should be damped with sulphuric acid and again heated.
By-prodiicts. — In chemical manufactories, secondary product*, such as tie sulphurous gas of the above reaction, are termed by-pro- ducts, and, if oT value, are utilized. In the present case the gas has no immediate interest, aod is therefore allowed to escape. When
id .y Google
158 THE METALLIC RADICALS.
very pure sulphurous acid gas is required for experiments on the small scale, this would be the best method of making it, a delivery- tube being adapted by a cork to the mouth of & flask containing the iwid and metal. The sulphate of mercury would then become the by-product.
Mercuric oceysvlphate. — Water deeompoaes mercuric sulphate into a soluble acid salt and an insoluble yellow oijsulphate (Hg,Oj SOj). The latter is called Turpeth mineral, from its resemblance in color to the powdered root of Ipom^ea turpelhum,, an Indian sub- stitute for jalap, The yellow sulphate of mercury [Hydrargyri Sulphas Flava, U. 8. P.) was formerly official in the pharmaooptela of Great Britain, but is now seldom used.
Fifth Synthetical Beaction. — Rub a portion of the dry mercuric sulphate of the previous reaction with as much mercury as it already contains ; the product, when the two have thoroughly blended, is mercurous sulphate (IIg,SOj): it may be retained for a subsequent experiment.
Molecular WetgM.—Th^ exact proportion of mercury to sulphate is merely a matter of calculation ; for the combining proportion of a compound {if it possess any combining-power) is the sum of the com- bining .proxwrtions of its constituents. In other words, the comfcj'n- ing weight of a molecule is simpiy the sum of the weights of Ha constituent atoms, or, more generally, the molecular weight of a compound is the swm of the atomic weights of its elements. In accordance with this rule (sometimes called the fourth law of chemi- cal combination, though only a deduction from the flrsl^p. 36}, 296 of mercuric sulphate and 300 of mercury (about 3 to 2) are the exact proportions necessary to the formation of mercurous sulphate.
The Two Chlorides. Sixth Synthetical Reaction. — Mix thoroughly a few grains of dry mercuric sulphate with about four-flftbs ita weight of chloride of sodium, aud heat the mixture slowly in a test-tube in a fume-chamber or in the open air to leeward of the operator ; mercuric chloride (HgCL), or corrosive sublimate (^Sydrargyri Perchloridum, B. P., Mydrargyri Chloridum, Gorrosivum, U. S. P.), aublimwi and condenses in the upper part of the tube in heavy color- less crystals or a crystalline mass. Somewhat larger quan- tities (in the proportion of 30 of sulphate to 16 of salt, and, vide infra, 1 of black oxide of manganese) may be sublimed in a pair of two-ounce or three-ounce round-bottom galli- pots, the one inverted over the other, and the joint luted by moist fireclay (the powdered clay kneaded with water to the consistence of dough). The luting having been allowed to dry (somewhat slowly, to avoid cracks), the
id .y Google
MERCURY. 159
pots are placed upright on a sand-tray (plate-shape answers Tery well), sand piled round the lower and a portion of the upper pot, and the whole heated over a good-sized gas- flame for an hoar or more. Red Iodide of Mercury and Calomel may be sublimed in the same way. The former requires less, the latter more, beat than corrosive subli- mate.
HgSO. + SlSraC! = HgCL + Na,SO,
Mercniic ChloridB ol Memric Sulpliate of
Note. — If the mercuric sulphate contain any mercurous sulphate, some calomel may he formed. This result will be avoided if 2 or 3 per cent of black oxide of manganese be previonsly raised with the ingredients, the action of which is to eliminate cnlorine from the excess of chloride of sodium used in the process, the chlorine convert- ingany calomel into corrosive sublimate.
Precaution. — The operation is directed to be conducted with care in a fume-chamber or in the open air, because the vapor of corrosive sublimate ,which might possibly escape, is very acrid and highly poi- sonous. Its vulgar name is indicative of its properties.
Tea grains of perchloride of mercnij and the same quantity of chloride of ammonium in one pint of water, form the Liquor Hydrarqyri Pereliloridi, B. P.
Seventh Synthetical Eeaction. — Mix a few grains of the mercurous sulphate of the fifth reaction with about a third of its weight of chloride of sodium, and sublime in a test- tube; crystalline mercurous chloride (HgOl) or calomel {Eydrargyri Subchloridum, B. P., Hydrargyri Ohloridum Mite, TJ. S. P.) results. Larger quantities may be pre- pared in the manner directed for corrosive sublimate, a somewhat higher temperature being employed ; similar precautions must also be observed. The proportions are 10 of mercuric sulphate to 7 of mercury and 5 of dry chlo- ride of sodium. " Moisten the sulphate of mercury with some of the water, and rub it and the mercury together until globules are no longer visible; add the chloride of sodium, and thoroughly mix the whole by continued tritu- ration. When dry sublime by a suitable apparatus into a chamber of such size that the calomel, instead of adhering to its sides as a crystalline crust, shall fall as a fine (dull- white, powder on its floor. Wash this powder with boiling distilled water until the washings cease to be darkened by a drop of sulphydrate of ammonium. Finally, dry at a heat not exceeding 212°, and preserve in a jar or bottle impervious to light."
id .y Google
160 THE METALLIC RADICALS.
Hg,SO, + 2NaCl = 2HgCl + NaSO,
Mercurous Cbloiide of MeicaroDe SalphHIo of
sulphate, sodium. obloiide. sodiDin,
The term calomel {wcAid i:alos, good, and pi^af, melas, black) is Baid to relate to the use of the salt as a good remedj for btacJc bile, but probably was simply indicative of the esteem in which black sul- phide of mercH^ was held, the cotopound to which the name calomel was first applied.
Test for corrosive sttbUmaie in caiomel. — It the mercuroos sul- phate contains mercuric snlphate, some mercuric chloride will also be formed. Comwive sublimate is soluble in water, calomel insolu- ble ; the presence of the former may therefore be proved by boiling a few grains of the calomel in distilled water, filtering and testing by sulphuretted hydrogen or sulphydrate of ammonium as described hereafter. If coirosive sublimate is present, the whole bulk of the calomel must be washed with hot distilled water (ill the filtrate eeases te give any indications of mercarj. Corrosive sublimate ia more soluble in alcohol, and still more in ether, calomel insoluble. Ether in which calomel has been digested should, therefore, after filtration, yield uo residue on evaporation. Caiomel is converted by hydrocyanic acid into mercuric salt, with separation of metallic mercury.
Note. — The above process is that of the Pharmacopceias ; but calomel may also be made by other methods. Calomel mixed with lard forms the Uhguentwm Bydrargyri Subchloridi, B. P., and with sulphurated antimony, guaiacum vesin and castor oil, the PUvla, Hydrarqyri SubcMoridi Composita, B. P., Pilvla Antimonii Composifa, U. S. P., or " Plummer's Fills."
The two Oxides.
Eighth Synthetical Seaciion. — Evaporate the mercuric nitrate of the third reaction to dryness in a small dish, in a funie-chamlier, or in the open air if more than a few grains have been prepared, and heat the residue till no more fumes are evolved; mercuric oxide (HgO), "Red Precipitate," the Red Oxide of Mercury {^Hydrargyri Oxi- dum Rubrum, B. P. and U. S. P.) remains.
3(Hg2N05) = 2HgO + 4N0^ + 0,
The nitric constituents of the salt may be partially eeonomiEcd by preTiously thoroughly mixing with the dry mercuric nitrate as much mercury as is used in its preparation, or as much as it already contains (ascertained by calculation from the atomic weights and the weight of nitrate under operation, as in making me'rcurous sulphate p. 158), and well heating the mixture. In this case the free mercury iS also converted iiite mercuric oxide. This is the official process, the Pharniacopceial quantities being four ounces of mercury dissolved
id .y Google
MEECUaV. 161
in four and a half fluidouiices of nitric acid diluted with two onooea of water, the solution evaporated t« dryness, tie residne thoroughly mixed with fonr ounces of mercury, and the whole heated until acid vapors cease to be evolved. (Merenric oxide is tested for nitrate by heating a little of the sample in a f«st-tube, when orange nitrous vapors are produced and are visible in the upper part of the tube, if nitrate is present.)
Hg2N0. + Hg = 2HgO + 2N0,
Hercnris Uercurv. Mercuric Mtrlc
nitrate. oiide. peroiifle.
Mercuric oxide is an orange-red powder, more or less crystalline Mcording to the extent to which it may have been stirred during preparation from the nitrate, much rubbing giving the crystals a pulverulent character. Mixed with yellow wax and oil of almonds it yields the Ungventum Bydrargyri Oayidi Rubri, B. P. (1 part in 8). A similar ointment is ofQcial in U.S.F,
Ninth Synthetical Reaction. — To solution of corrosive sublimate in a test-tube or larger vessel add solution of potasb or soda, or lime-water ; yellow oxide of mercury, or mercuric oxide (HgO), is precipitated.
HgCI, + Ca3H0 = HgO + CaCl^ -f H,0
Eighteen grains of corrosive sublimate to ten ounces of lime-water form the Lotio Hydrargyri Flava, B. P. The precipitate only dif- fers physically from the red mercuric oxide ; the yellow is in a more minute state of division than the red.
Tenth Synthetical Reaction — To calomel add solution of potash or soda, or lime-water; black oxide of mercury, or mere urous oxide (Hg^O) is produced, and may be filtered off, washed, and dried. (This reaction and the formation of a white curdy precipitate, on the addition of solution of nitrate of silver to the filtrate from the mercurous oxide, acidified by nitric acid, form sufficient evidence of a powder being or containing eaiomel. The curdy precipi- tate is chloride of silver.)
Thirty grains of calomej to ten ounces of lime-water form the Lotto Bydrargyri Nigra, B. P.
2HgCl 4- OaSHO = Hg,0 + CaCl, -f H^O
Mercurous Hydratn of Mercurona Clilorlde of Witsc.
cbloMde. ealdnm. oiiae. ciloiun).
14*
id .y Google
THE METALLIC RADICALS.
(S) Anal^ical Baactions (Tests).
First Analytical Reaction. — The Copper Test. Deposi- tion of mercury upon, and eufalimation from copper — PJace a small piece of bright copper, about half aii inch Jong and a quarter of an inch broad, in a solution of any salt of mercury, mercurous or mercuric, and heat in a test-tube ; the copper becomes coated with mercury in a fine state of division. (The absence of any notable quantity of nitric acid must be insured, or the copper itself will be dissolved. See below.) Pour away the supernatant liquid from the copper, wash the latter once or twice by pouring water into, and then out of, the tube, remove the metal, take off excess of water by gentle pressure in a piece of filter-paper, dry the copper by passing it quickly through a flame, holding it by the fingers ; finally, place the copper in a dry narrow test-tube, and heat to redness in a flame, the tube being held nearly horizontal ; the mercury sublimes and con- denses as a white sublimate of minute globules on the cool part of the tube outside the flame. The globules aggregate on gently pressing with a glass rod, and are- ospecially visible where flattened between the rod and the side of the test-tube.
Notes on the teat.- — This is a valuable teat, for seveial reaaous: It is very delicate when pciformed with caro It bungs before the ■observer the element itself— one which from its metallic lustre and fluidity canaot be mistaken for any other. It separates the element both from mercurous and mercuric salts Mercury can m this way be readily eliminated in the presence of most other sntisfances, or- ganic or inorganic.
In performiuK the test the presence of any quantity of nitric &ca& may be avoided by adding an altvah until a, slight permanent preci-
Eitate appears, and then reaoidiiyin^ With a few dropi of acetic or ydrochloric acid, or, if tliey fail to reditsolve the precipitate, with a very few drops of niliic acid.
Second Analytical Beaciion, — To a few drops of a solution of a mei-curic salt (corrosive sublimate, for example) add solution of iodide of potassium, drop by drop; a precipi- tate of mercuric iodide (Hgl^) forms, and at first quickly redisBolvee, but is permanent when sufiicient iodide of potassium has been added. Continue tbe addition of iodide of potassium ; the precipitate is once more redissolved.
id .y Google
MEECUBT. 163
Notes. — When first precipitated, mercuric iodide ia yellowish-red, hut eoon changes to a beautiful scarlet. Its solnbilily eitheria solu- tion of tie mercuric salt or in solution of iodide of potassium renders the detection of a small quantity of a mercuric salt hy iodide of potassium, or a Bmall quautity of an iodide by a mercuric solution, difiicalt, and henc« lessens the value of the reaction as a test. But
Rubrum,, B. P. and U. S. P.). Mercuric iodide thus made has the same composition as that prepared by direct combination of its ele- ments. Eqiiiyalent proportions of the two salts must be osed in making the preparation (HgOl5=2'Il ; 2KI=332). About 4 parts of corrosire sublimate are dissolved in 50 or 60 of water (warmth
Suicltens solution), and 5 of iodide of potassinm in 15 or; 20 of water, le solutions mixed and the precipitate collected on a filter, drained, washed twice with distilled water and dried on a plat* over a water- bath. (For additional properties of mercuric iodide, see page 155.) The mercury in mercuric or mercurons iodide is set free and sub- limes in globules on heating either powder with dried carbonate of sodium m a test-tube ; the iodine may be detected by digesting with solution of soda, filtering, and to the solution of iodide of sodium thus formed adding starch paste and acidulating with citric acid, when blu& iodide of starch, results.
HgOl, -J- '3KI = Hglj -t- 2K01
Red iodide of mercury mixed with white wax, lard, and oil forms the UngVf^htiim Hydrargyri Jodidi Bubri, B. P. Donovan's Solution contained mercmic and arseuious iodides.
Third Analytical Reaction. — Add a solution of mercuric salt to solution of amiuonia, taking care that the mixture, after well stirring, still smells of ammonia ; a wliite pre- cipitate falls.
Ammoniated Sleroury.
Performed in a test-tube, this reaction is a very delicate test of the presence of a mercuric salt ; performed in Urger vessels, tlie mercuric salt being corrosive sublimate (3 ounces dissolved in 3 pints of distilled water, the solution poured inffl 4 fluidonnces of Solution of Ammonia, and the precipitate washed and dried over a water- bath), it is the usnal process for the preparation of "white precipi- tate," the old " ammonio-chloride," or "amido-chloride of mercury," now known asAmmoniated Mercury (ffj/cirarjryrMm ^tomonjatum, B. P., and U.S. P.).
Constitution of Ammoniated JtfercMry.— This preei^tate is con- sidered to be the chloride of mercuric-ammonium {NHsHg"Cl)— ; that is, chloride of ammonium (NHjCi) in which two atoms of univalent hydrogen are replaced by one bivalent atom of mercury.
id .y Google
104 THE METALLIC RADICALS,
HgOl, + 2Nn,nO = NH,Hg"Cl + NH
Varieties of Ammoniated Mercv/ry. — If the order of mixiDg be reversed and ammonia be added to solution of mercnrie chloride,
, doable chloride of mercuric ammouium and mercnry resolta (NH.HgCl.HgCl,): it contains 76.55 per ceot. of mercnry. Pre- vionBly to the year 1826, " white precipitate" was officially made by adding a fixed alkali to a solntion of eqwal parts of corrosive subli- mate and sal-ammoniac; tliis gave a double chloride of mercuric ammoniura and ammonium (NH^gOl.Nn.Ol), containing 65.57 jier cent of mercnry. This compound is now known as "fttsible white precipitate," becanae at a temperature somewhat below cednees it ftises and then volatilizes. The " white precipitate" which has been official since 1826 contaiiis 79.52 per cent, of mercnry. The true compound may be distinguished as "infusible white precipitate," from the fact that when heated it volatilizes without fusing. An oint- ment of this body is official ( Unguenium Hydrargyri Ammoniati, B. P. and U. S. P.). Prolonged washing with water converts " white precipitate" into a j-ellowish eomponnd (NH.HgOl, HgO) ; hence the official preparation is seldom, thoroughly freed from tJie chloride of ammonium which is formed during its manufacture, and which, if present in larger proportion than seven or eight per cent., gives the character of partial or complete fusibility to the compound. Note. — Chloride of mercuric ammonium is only one member of a large class of similar compounds, derivable from the various salts of ammonium by displacement of atoms of hydrogen by other atoms.
The composition or ammon' '' ' " ■' ■■ -" t..,..j..
of copper, made without e
■ lis
The composition of the crystals of ammonio-sulphate of copper (p, 152) is consistent with the second of the following formulre, the first being that of sulphate of ammonium : —
Ou" 1
\ SO.
Fourth Analytical Reaction Pass sulphuretted hjdro-
gcT! through a mercuric solution; a black precipitate of inerciirie sulphide (HgS) falls.
Note. — Sulphuretted hydrogen also precipitates merourons sul- phide (HgjS) fcom mercurouB solutions; and m appearance the pre-
id.y Google
cipitates are alike ; hence this reagent does not diatiognish between merourous and mercuric Baits. But in the course of systematic analysis, mercuric salts are thrown down from solution as sulphide after mercnrons salts have been otherwise removed. The sulpnides
Note. — An insufficient amount of the gas gives a whit« or colored precipitate of oxysulphide.
Etiiiops Mineral, the Hydrargyri Sidphuretuw, cum Sttlphure, is a mixture of sulphide of mercury and sulphur, obtained on tritu- rating the elements in a mortar till globules are no longer visible. Its name is probably in allusion to its similarity in color to the skin of the -fflthiop. It was formerly official. .
Vetfitilion is mercuric sulphide prepared by heating together sal- phnr and mercury, and snbliming the mixture [Hydraryri Stdphu- Tetum Ruhruw,, U. S. P.).
Fifth Analytical Eeaction — To a solution of a mercuroua salt (the mercnrous nitrate obtained in the second syn- thetical reaction, for example) acid hydrochloric acid, or any soluble chloride ; a white precipitate of calomel (HgCl) occurs.
This reaction was formerly official in the Dublin Phar- macopceia as a process for the preparation of calomel.
Sixth Analytical Reaction. — To solution of a mei'curous salt add iodide of potassium ; green mereurous iodide (Hgl) is precipitated.
Seventh Analytical Seaction. — To a mereurous salt, dis- solved or undissolved (calomel), add ammonia ; black salt (chloride) of mereurous ammonium (NH^Hg^Cl) is formed.
Other tests for Mercury.
The elimination of mercury in the actual state of metal by the copper test, coupled with the production or non- production of a white precipitate on the addition of hydro- chloric acid to the original solution, is usually sufHcient evidence of the presence of mercury and its existence as a mereurous or mercuric salt. But other tests may some- times be applied with advantage. Thus, metallic mercury Is deposited on placing a drop of the solution on a plate of gold (sovereign or half-sovereign), and touching the drop and the edge of the plate simultaneously with a key; an electric current passes, under these circumstances, from the gold to the key, and thence through the liquid to the gold, decomposing the salt, the mercury of which forms a white metallic spot on. the gold, while the other elements go to
id .y Google
166 THE METALLIC RADICALS.
the iron. This is called the galvanic test, and is useful for
clinical pur poses. Solution of stannous chloride (SnCl),
from the readiness with which the salt forms stannic chlo- ride (SnClJ, gives a white precipitate of mercurous chloride in mercuric solutions, and quickly still further reduces this mercurous chloride or other mercuric salts to a grayish mass of finely divided mercury ; this is the old magpie test, probably so called from the white and gray appearance of the precipitate. The reaction may even be obtained from such insoluble mercury compounds as "white precipitate."
Confirmatory tests for mercuric and mercurous salts
will be found in the aotion of solution of potash, solution of aoda, lime-water, solution of ammonia, and solution of
iodide of potassium. ( Vide pages 162 to 164.) Normal
alkaline carbonates produce yellowish mercurous cai'bonate, andbrownish-redmercuric carbonate, bothof them unstable. . — —Alkaline bicarbonates give mercurous carbonate and
white (soon becoming red) mercuric oxysalt. Yellow
chromate of potassium (K,CrO,) gives, with mercurous salts, a red precipitate of mercurous chromate (Hg^CrO^).
Mercury and all its compounds are volatilized by heat:
the experiment is most conveniently performed in a test- tube.
Antidote. — Albumen gives a white precipitate with solu- tion of mercuric salts ; hence the importance of administer- ing white of egg while waiting for a stomach pump in case of poisoning by corrosive sublimate.
QUESTIONS AND EXERCISES.
2 IS. Name tio cliief ore of mercury, and describe a process for the extraction of the metal.
279. In what state does mercury exist in " Gray Powder?"
280. What other preparations of metallic mercury itself are em- ployed in medicine !
281. State the relation of the mercnrona to the mercuric eompotindB.
282. Distingnish between an alloy and ao amalgam.
283. State the formulse of the two Iodides of Mercury.
284. Under what cirenmstances does mercarie iodide aaanme two different colors ?
285. Illustrate the chemical law of Mnltiple Proportiona as ex- plained by the atomic theory, employing for that purpose the stated composition of the two iodides of mercury.
286. Write down tlie formulfe of Mercurous and Mercuric Nitrates and Sulphates.
id .y Google
LEAD. 167
281. How is Mercuric Sulphate prepared ?
288. What is the formula of " Turpeth Mineral !"
289. Describe the proceBses necessary for the conversion of mer- cury into Calomel and Corrosive Sublimate, using diagrams.
290. Why is black oxide of manganese soriietimea mixed with the other ingredientfl in the preparation of corrosive sublimate !
291. Give the chemical and physical points of difference between calomel and corrosive sublimate.
292. How may a small quantity of calomel in corrosive sublimate be detected?
293. Work ont a sum showing how much mercury will be required in the manufacture of one tfln of Calomel. Ans. 11 cwt nearly.
294 Mention official preparations of the chlorides of mercury.
295. Give the formuhe and mode of formation of the Bed, Yellow, and Black Oxides of Mercury, employing diagrams.
296. Explain the action of the chief general f«8t for mercury.
297. How ate mercurous and mercuric salts analytically distin- goished !
398. Give a probable view of the constitution of Hydrargyrtm, Ammoniatum, and an equation showing bow it is made.
299. What is the best temporary antidote in cases of poisoning by mercuiy %
Symbol Pb. Atomic weight 207.
Source. — The ores of lead are numerous ; but the one from which the metal is chietty obtained is the sulphide of lead (PbS), or galena (from 7ns.iiv^, golene, tranquillity, perhaps from its supposed effect in allaying pain).
Pr^aration. — The ore is first roasted in a current of air ; much sulphur is thus burnt off as sulphurous acid gas, while some of the metal is converted into oxide and a portion of the sulphide oxidized to sulphate. Oxidation being stopped when the mass presents cer- tain appearances, the temperature is raised, and the oxide and sul- phate, reacting on undecomposed sulphide, yield the metal and much sulphurous acid gas : — ■
Uses. — The uses of lead are well known. Alloyed with arsenicum it forms common slwt, with antimony gives type-metal, with tin sol- der, and in smaller quantities enters into the composition of Britan- nia metal, pewter, and other alloys.
The salts of lead used in pharmacy and all other preparations of lead are obtained, directly or mdu^ctly, irom the metal itself. Heated in a current of air, lead combines with oxygen and forms oxide of lead {PbO} {Plvmbt Otmdum. B. P. and U. S. P.), a yellow powder (massicot), or, if fused and solidified, a brighter reddish-yellow heavy
id .y Google
168 THE METALLIC flADICALS.
mass of briglit scales, termed litharge (from ?j^o( lithos, a atone, and apyiipo;, argv/ros, silver). It is itom this oxide that the chief lead compouads are obtained. Oside of lead, hj farther roasting in a current of air, yields red had {or minium), PbsO,, or Pl>0,2FhO. Both oxides are mnch used bj painters, paper-stainers, and glass- manufacturers. Wliite lead is a mixture of carbonate (PbOO„) and hydrate of lead (Pb2H0} (commonly 2 molecules of the former to 1 of the latter), usually ground np with about 7 per cent, of linseed oil ; it is made by exposiog lead, cast in spirals or little gratings, to the action of air, acetic fumes, and carbonie acid, the latter generated from decaying vegetable matter, such as spent tan ; oxyacetate of lead slowly bpt contiunonsly forms, and is as continuously decom- posed by the carbonic acid with production of hydrate and carbonate, or dri/ white lead. The grating-like masses, when ground, form the heavywhite pulverulent official Phimhi Garbonas, B, P. and F. S. P. The latter is the active constituent of Uiigttentvmi, Pliimii Oar- bonatia, B. P. and U. 8. P., the old UnguerUv/m Cerussce.
Lead compounds are poisonous, producing satnmiae colic, or even paralysis. These effects are termed saturnine from an old name of lead, Saium. The alchemists called lead Saturn, first, beeanse they thought it the oldest of the seven then known metals, and it might therefore be compared to Saturn, who was supposed to be the falser of the gods, ana, 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.
Quartttvalence. — ITie atom of lead is sometimes quadrivalent (Pb""); but in most of the compounds used in medicine it exerts bivalent activity only (Pb").
(a) Synthetical Beadions. Acetate of Lead. First Synthetical Reaction. — Place a few grains of oxide of lead in a test-tube, add about an equal weight of water and two and a half times its weight of acetic add, and boil ; the oxide dissolves and forms a solution of aeetate of lead (PbaCjHaOj). When cold, or on evaporation (the solu- tion being kept faintly acid), crystals of acetate of lead (PbaCjH^O,, SHjO) are deposited. Larger quantities are obtained by the same method.
PbO -f SHG^HaO, = PbaOjHaO, + H,0
Oxide of lend. Acetic scid, Acetale o( lead. Water.
This is the official processs for Pliimbi Acdas, B. P. and U. S. P. The salt is vulgarly termed Sugar of Lead, from its sweet taste. Besides its direct use in pharmacy, it forms three-fourths of the
id .y Google
LEAD. 1G9
Pilula Plimihi cwm Opio, B. F., is the chief constituent of Unc/nen- tum Humbi Aoetafis, B. P., and an ingredient ia Sv^positoria Piumhi Gomposita, B, P.
Snbaoetate or Oxyaeetate of Lead, Second Synthetical Reaction. — Boil acetate of lead with about four times its weight of water and ratlier more than two-thirds its weiglit of oxide of lead ; the resulting filtered liquid is solution of oxyaeetate of lead, Liquor Plumbi Buhaeetatis, B. P. and U. S. P.
The official (B. P.) lAquov is made by boiling 5 ounces of acetate and 34- of oxide in 1 pint of distilled water for half an. hour {con- stantly stirring), filtering;, and making up for any loss by evaporation by diluting the filtrate to 1 pint.
A similar solntioa was used by M. Goulard, who called it E<f.- tradum Satumi, and drew attention to it iu 1770. It is now fre- quently termed Qovlard's- Extract. A more dOute solution,! of lAqtior and 1 of spirit in 80 of distilled water, is also official in the Pharmacopreiaa, nuder the name of Liquor Plumbi Subare- tatis Siltiims. The latter is commonly known as Goidwrd Water. ITie stronger solntion is the chief ingredient in Ungueiitum Plumbi Sviacetatis Gompoeitum, B. P., a slight modification of the old GotUard's Gerate. Similar preparations aJ-e official in the United States Fharmacopteia.
Oxvaeetatesoflead.—Th& official subacetate of lead is not a defi- nite ohemioal salt. It is proljably a mixture of two snbacetates of lead, which are well-known crystalline compounds, and which the author is disposed to regard as having a constitution similar to that he has already indicated for some other salts (see Iron, Antimony, and Bismuth).
Acetate of Ia».A {3 molecules) . . . . Fb, 60,n„0,
P p 1 Pjro-oxjacetate oflead Pba04C5H,03
"■^■JGoulard'soxyacetateoflead Pb^O^aOjHjO,
Oxideof lead [3 molecules) PbjOj
PbO + Fb205HsOj = Fbs02C5H,05 „ or 3PbO + 3(Pb2C5H,0,) = Pb30405H305 + Pb,O(20,H50,
Third Synthetical Reaction. — Digest a few grains of red lead in nitric acid and water; nitrate of lead (Pb2N03) is formed, and remains in solution, wbile a puce colored per- oxide of lead (PbOj) is precipitated. 15
id .y Google
METALLIC EADH
Nitrate of Lead. Bed Lead. Peroxide of Lead.
above reaction sevves to briag before tie reader two other ozides of lead, namely, red lead (PbjO,) aad peroxide of lead (PbOj), In the latter oxide the quadrivalent character of lead is obvious. Nitrate of lead is nsed officially in preparing iodide of lead ; for tbfe purpose the above mixture is filtered, the precipitate of peroxide of lead purified from adhering nitrate by passing hot water through the niter, the filtrate and washings evaporated to dryness to remove excess of nitric acid, the residual nitrate of lead redissolved by ebulli- tion with a small quantity of hot water, and the Bolntion set aside to crystallize, or a portion at once used for the following experiment. Nitrate of lead forms white crystals derived from octahedra.
Iodide of Lead.
Fourth Synthetical Eeaation. — To a neutral solution of nitrate of lead add aolutiou of iodide of potassium ; a pre- cipitate of iodide of lead {Pbl^) falls (Plumhi lodidum, B. P. and TJ. S. P.). Equal weights of the salts may be used in making large quantities.
pbSNO, -I- 2KI = Pbl, + SENO,
Iodide of lead is the chief ingredient in Errmlasti-um Tliim,bi lodi- di, B. P., and Unguentum Plii/mhi lodidi, B. P.
Crystals of Iodide of Lead. — Heat the iodide of lead with the supernatant liquid, and, if necessary, filter ; the salt is dissolved, and again separates in golden crj-stalline scales as the solution cools.
Oleate of Lead (Lead Plaster). Fifth SynihelicalSeaclion.— ^Boi\ together in a small dish some very flnely-powdered oxide of lead, with about twice its weight of olive oil, and ten or twenty times as much water, well stirring the mixture, and from time to time re- placing water that has evaporated ; the product is a white mass of oleate of lead (PbSCisHasf^s) (Fmplastrum Plumhi, B. P, and IT. S. P.), glycerine remaining in solution in the water. Larger quantities are prepared in the same manner. 3PbO -I- 3H^0 + 2(0,Hj3C„H^OJ = 3(Pb30,gHj50J +
id .y Google
LEAP. 171
The action between the oxide of lead and olive oil is slow, requir- ing several hours for ita completion ; but a sufBcient amount of plas- ter to illnatrate the operation is formed in a much shorter time.
The glycerine may be obtained by treating the aqueous product of the above reaction irith sulphuretted hydrogen to remove a trace of lead, then digesting with animal charcoal, filtering and evapo- rating. Buton thelarge scale glycerine is now usually produoed as a by-produet in the manufacture of candles ; for its elements arefonud in all vegetable and animal fats. ( Vide Index.}
Modes of forming chloride, sulphide, chroiiiate, sulphaie, hy- drate, and other salts of lead are incidentally described in the follow- ing analytical paragraphs.
(b) Beaciion8 having Analytical Interest (Teuls).
First Analytical BeacHon. — To a solution of lead salt (acetate, for example) add hydrochloric acid ; a wJiite pre- cipitate of chloride of lead (PbClJ is obtained. Boil the precipitate with much water; it dissolves, but, on the so- lution cooling, is redepoaited in small aeicolar crystals. Pilter the cold solution, and pass sulphuretted hydrogen through it ; a black precipitate (sulphide of lead, PbS) shows that the chloride of lead is soluble to a slight extent ill cold water,
Note.— A white precipitate on the addition of hydrochloric a«id, soluble in hot water, and blackened by sulphuretted hydrogen, suffi- ciently 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 load, chloride of lead being slightly soluble in cold water. Hydrochloric acid will be found to be a useful but not a delicate test for lead.
Second Analytical Meaolion. — Through a dilute solution of a lead salt pass sulphuretted hj'drogen ; a black pre- cipitate of sulphide of lead (PbS) occurs.
Lead in Water. — 'Che foregoing is a very delicate test. Should a trace of lead be present in water used for drinking-purposes, sulphu- retted hydrogen will detect it. On passing the gas through a pint of such water, a brownish tint, more or less deep, is produced. If the tint is scarcely pei-ceptible, set the liquid aside for a day ; the gas will become decomposed and a thin layer of sulphur be found at the bottom of the vessel, white if no lead be present, but more or less browa if it contain sulphide of lead.
id .y Google
112 THE METALLIC RADICALS.
Third Analytical Reaction. — To solution of a lead salt add sulphydrate of ammonium ; a blacit precipitate of sul- phide of lead falls, insoluble in excess.
Fourth. Analytical Reaction — To solution of a lead salt add solntion of chromate of potassium (KjCi'O J ; a yellow precipitate of chromate of lead (PbCrO^) is formed, inso- luble in weak acids.
OAromies,— This reaction lias technical as well as analytical in- terest. The precipitate is the common pigment termed chrome yel- low, or lemon chrome. Boiled wifi lime and water, a portion of the chromic elements are removed, and an oxychromate, of a bright red or orange color [orange chrome), is produced.
M/lh Analytical Beaction. — To solution of a lead salt adddilutesnlphuricacid, or solution of a sulphate J a white precipitate of sulphate of lead (PbSOJ falls.
Sviphate of lead is slightly soluble in strong acids, and in solu- tions of alkaline salts ; it is insoluble in acetic acid.
lu dilute solutions this sulphuric reaction does not take place im- mediately ; the precipitate, however, falls after a time ; its appear- ance may be hastened by evaporating the solution nearly to dryness and then rediluting.
The white precipitate alwaj^ noticed in the vessels in which diluted sulphuric acid is kept, is sulphate of lead, derived from the leaden chambers in which the acid is made; solubility in strong acid and insolubility in weak, explains its appearance.
Antidotes.— ¥Km the insolubility of sulphate of le-ad in water, the best antidote in a case of poisoning by the acetate or other soluble salt of lead, is a soluble sulphate, such as Epsom salt, sulphate of sodium or alum, vomiting bemg also induced, or tho stomach-pump applied as quickly as possible.
Other tests for lead will be found in the reaction with iodide of potassium (vide p. 110); with alkaline carbonates, a white precipitate (2PbCO,-f-Pb2HO) insoluble in excess; with alkalies, a white precipitate (Pb2H0) more or less soluble in excess ; with alkaline phosphates, arseniates, ferrocyanides and cyanides, precipitates mostly insoluble, but of no special analytical interest. Insoluble salts of lead are decomposed by sohitions of potash (KHO)of soda (NaHO).
Tho metal is precipitated in a beautifully crystalline state by metallic zinc and some other metals ; the lead tree is
thus forraed.^ -The blowpipe-Jlame decomposes solid lead
compounds placed in a small cavity in a piece of charcoal, a soft malleable bead of metal being produced, and a yel- lowish ring of oxide deposited on tlia charcoal.
id .y Google
QUESTIONS AND EXBEOISBS.
300. "Write down equations descriptive of the smelting of galena.
301. Mention some of the alloys of lead.
302. How is litharge prodncedt
303. Give the forraute of white lead and red lead. 304 Describe the manufacture of white lead.
305. What is the qiiautivalence of lead?
306. Draw a diagram expressive of the formation of Acetate of
SOY. Describe the preparation and composition of Ldqiwr Piwmbi Subacetaiis.
308. What is the action of nitric acid on red lead, litharge, and metallic lead?
309. How ia the official Iodide of Lead prepared ?
310. Describe the reaction between oxide of lead, water, and olive oil, at the temperature of boiling water, and give chemical formnlse esplanatory of the conatitution of the products.
311. Mention the chief testa for lead.
312. How would you search for lead in potable wat«r J
313. What is the composition of chrome yellow ?
314. State a method whereby lead, barium, and silver may be separated.
315. Name the best antidote in case of poisooing by salts of lead.
Symbol Ag. Atomic weight 108.
.SoMrce.— This element occurs in nature in the free state and as ore, the common variety being sulphide of silver (AgjS) in combina- tion with much sulphide of lead, formiug argenti^eroiis galena.
Preparation. — The lead from galena {p. 161) is melted and slowly cooled ; crystals of lead separate and are raked out from the still fluid mass, and thus an alloy very rich ia silver ia finally obtained i this is roasted in a current of air, whereby the lead is oxidized and removed as iitharge, pure silver remaining. Other ores undergo various preparatory treatments according to their nature, and are then shaKen with mercury, which amalgamates with and dissolves the particles of silver, the mercury being subsequently removed from the amalgam by distillation. Soils and minerals containing metallic silver are also treated in this way. Aa important improvement in the amalgamation process, by which the mercury more readily unites with the silver, consists in the addition of a small proportion of so- dium to the mercury^a recent discovery, simultaneously made in England by Grookes, and in New York by Wurtz. 15*
id .y Google
174 THE METALLIC EADICALS.
Reactions having (ct) Synthetical and (6) Analytical Interest.
(a) Synthetical Eeactions.
Impure Nitrate of Silver.
First Synthetical ReoMion. — Dissolve a silver coin in
nitric acid; nitric oxide gas (NO) and nitrous anbydride
(NjOj) are evolved, and a solution of nitrates of silver and
copper obtained.
Silver Coinage.- — F«re silver is too soft foT use as coin, it is there- fore hardened bj allojiDg with copper. The silver money of England contains 1.5, of ITrance 10, and of Prossia 25 per cent, of copper. One pound troy of standard silver is coined into 66 shillings, of which the metal is worth from 60s. to 62s. according to the maTket price of silver. The standard fineness of silver is 0.925, three alloy in 40. The fineness of the French standard silver is 0.900 in the five-franc piece i but an inferior alloy of 0.835 is used for the lower denomina- tions. The single-franc piece, composed of the latter aOoy, is still made to weigh five grammes, the weight originally chosen for the franc aa the unit of flic monetary scale when the fineness of the coin was 0,900. It has now become a token, like the British shilling, of which the nominal value exceeds the metallic value. British silver coins are a legal tender in payments to the amount of 40s. only.
Chloride of Silver.
Second Synthetical Reaction. — To the product of the above reaction add water and hydroohloric aeid or a solu- ble chloride ; white chloride of siiver (AgCl) is precipitated, copper still remaining in solution. Collect the precipitate on a filter, and wash with water; it is pure chloride of silver.
Note. — The nitrates of silver and copper may also he separated by evaporating the solution of the metals in nitric acid to di'yneas, and gently heating the residue, when the nitrate of copper is decom- posed, but the ni&ate of silver unaffected. The latter may be dis- solved from the residual oxide of copper by water.
Pure Silver.
Third Synthetical Reaction. — Dissolve the chloride of silver of the previous reaction in alight excess of solution of ammonia, and immerse a piece of sheet copper in the liquid; metallic silver is precipitated, and after a time wholly removed from solntion. Collect the precipitate on a filter and wash with water; it is pure metallic silver, and is readily fusible into a single button.
id .y Google
Note. — Chloride of silver may also be reduced by fasion, in a cm- cible, with about half its weight of carbonate of sodium.' Chloride of silver may be obtained in crystals by evaporation of its solution
Pure Hitrate of Silver.
Fourth Synthetical Reaction. — Dissolve the pure silver of the previous reaction in nitric acid (3 of silver require abo«t 3 or 2^ of strong acid diluted with 5 of water), and remove excess of acid by evaporating the solution to dry- ness, slightly heating the residue; the product is pure nitrate of silver. Dissolve by heating with a small quan- tity of water; on the solution cooling, or on evaporation, colorless tabular crystals of nitrate of silver are obtained.
3Ag, -f- 8HN0, = 2N0 -|- GAgNO, -|- 4H^0
Notes. — The solution of p fatuw,, B. F,, Argewtwn, U. S. P.) in nitric acid, evaporatioi , crystallization eonstitut* the official process for the preparation of the nitrate {Argenti Nitrm, B. P. and U. S. P.) The salt fused, and pom«d into proper moulds, yields the white cylindrical sticks or rods {Argenti NtCras Fasa, U. S, P.) commonly termed eaustie (from Kotu, kaio, I bum), or Ivmar cavMic. {The alchemists called silver Diana or l/muj,, from its supposed mysterious connection with the moon.) The specimen of mirate of silver obtained in the al)ove reaction, dissolved in water, will be found useftil as an analytical reagent. Nitrate of silver is soluble in rectified spirit; but after a time reaction and decomposition occur.
Marking Ink. — Silver salts ai'e decomposed when in contact with organic matter, especially in the presence of light or heat, a black insoluble compound being formed. Hence the use of the nitrate in the mLLnufacture of indelible ink for marking iiueu.
Oxide of Silver, Mfth Synthetical Reaction. — To a few drops of solution of nitrate of silver add solution of potash or soda or lime- water; an olive-brownprecipitateof oxide of silver (AgjjO) occurs. The washed and dry oxide, like most silver com- pounds, is decomposed by heat with production of metal.
The Argenti Oxidum, B. P. and tJ. 8. P., is thns made, lime- water (solution of potash U. S. P.) being the precipitant employed. "" - ■"a half pints of hme-water will decompose half an ounce
SAgNO, -f CaSHO = Ag,0 -|- Ca2N0, + n,0
id .y Google
nb THE MBTALIIO RADICALS.
Methods of forming several other salts of silver are incidentally moLitioned in the following analytical paragraphs.
(a) HeacHons having Analytical Interest, (Tests.) First Analytical Beaction. — To a solution of a silver salt add liydrochloric acid or other soluble chloride ; a white curdy precipitate of chloride of silver falls. Add nitric acid, and boil ; the precipitate does not dissolve. Pour off tlie acid and add solution of ammonia; the precipitate dis- solves. Neutralize the ammoniacal solution by an acid ; the chloride of silver is re-precipitated.
This is the most characteristic test for silver. The precipitated chloride is also soluble in solationa of hyposulphite of sodium or cy- anide of potassium — facts of considerahle importance in photogrnhie operations.
Other analytical reagents than the above are occasionall3' useful. Sulphuretted hydrogen, or sulphydrate of am- monium, gives a black precipitate, sulphide of silver (Ag^S),
insoluble in alkalies. Solutions of potash or soda give
a brown precipitate, oxide of silver (Ag^O), converted into a fulminating compound by prolonged contact with am- monia. Phosphate of sodium gives a pale yellow pre- cipitate, phosphate of silver (AgjPOJ, soluble in nitric
acid and in ammonia. Arseniate of ammonium gives a
chocolate-colored precipitate, arseniate of silver (AgjAsO^),
already noticed in connection with arsenic acid. Iodide
or bromide of potassium gives ayellowish-white precipitate, iodide or bromide of silver (Agl or AgBr), insoluble in
acids and only slightly soluble in ammonia. Cyanide of
potassium gives a vfhite precipitate, cyanide of silver (AgCy), soluble in excess, sparingly soluble in ammonia, insoluble in dilute nitric acid, soluble in boiling concen- trated'nitric acid. Argenli cyanidum, TJ. S, P. is made by distilling a mixture of ferroeyanide of potassium and di- luted sulphuric acid and passing the resulting hydrocyanic acid into solution of nitrate of silver: HCy + AgNO, = AgCy + HNO„ the precipitate is well washed and dried.)
Yellow chromate of potassium (K^CrOJ gives a red
precipitate, chromate of silver (AgjCrOJ. Red chro- mate of potassium also gives a red precipitate, acid chro- mate of silver (Ag^CrO,,CrOs). Many organic acids
afford insoluble salts of silver. Several metals displace
silver from solution, mercury forming in this way a crys- talline compound known as the silver tree, or Arbor Diame. In the blowpipe flame, silver salts, placed on charcoal
id .y Google
COPPER, MERCUKY, LEAD, SILVER. Ill
■with a little carbonate of sodium, yield bright globules of metal, acconipanied by no incrustation as in the corres- ponding reaction with lead salts; the experiment may be performed with the nitrate, which first melts and then, like all nitrates, deflagrates, yielding a white metallic coating of eilver-which slowly aggregates to a button.
Antidotes. — Solntion of common salt, sal-ammoniac, or any other inert chloride should obviously bo administered where large doses of nitrate of silver have been swallowed, A quantity of sea-water or brine would convert the silver into insoluble cnloride, and at the same time produce vomiting.
QUESTIONS AND EXBE0ISB8.
316. By what process is silver obtained from argentiferous galena ?
317. What weight of English silver coin will yield one pound of pure nitrate of silver ?
318. How may the metal be recovered from an impure mixture of silver salts ?
319. Give a diagram showing the formation of nitrate of silVer from the metal.
320. Describe the reaction of lime-water and nitrate of silver.
321. Mention the chief test for silver, and the precautions to be observed in order that it may be distinguished from lead and mer- cury.
322. Name the antidote for silver.
DIRECTIONS POR APPLYING SOME OF THE POREGOINO REACTIONS TO THE ANALYSIS OP AN AQUEOUS SOLUTION OP SALTS OF OlS'E or THE METALS COPPEE, MeRCURY (EITHER AS MERCIiaOUS OR MERCURIC SALT), LeAD, SiLVEB.
Add hydrochloric acid : —
Silver is indicated by a white ciirdy precipitate, solu-
Mercurous salts also by a white precipitate, turned
black by ammonia. Lead by a white precipitate, insoluble in ammonia. Confirm by boiling another portion of the hydro- chloric precipitate in water ; it dissolves. If hydrochloric acid gives no precipitate, silver and mer- cnrous salts are absent. Lead can only be present in very small quantity. Mercuric salts may be present. Copper
id .y Google
118
THE METALLIC RADICALS.
may be present. Divide the liquid into three portions, and apply a direct test for each metal.
Lead is best detected by the sulphuric teat ; the tube being set aside for a time if the precipitate does not appear at once. Mercury is best detected by the copper test- If present,
it occurs as mercuric salt. Copper betrays itself by the blue color of the liquid under examination. Confirm by the ammonia test. If the above reactions are not thoroughly conclusive, confirmatory evidence should be obtained by the applica- tion of some of the other reagents for copper, mercury, lead or silver.
Table of short dieections tor applyin& some oe the fokegoina reactions to the analysis op an aqueous solution op salts of any ob all op the metals cop- PER, MeROCRY (either MEROUROUS OE MBECUaiC SALT,
OR both). Lead, Silver.
Add hydrochloric acid, filter, and wash the precipitate with a Bma\l quantity of cold water.
Ppt. Pb Hg Ag. Wash with boiling wat
Ppt.
ng Ag.
Add AmHO.
Add HNO3, white ppt.
Filtrate
Cu Eg Pb.
Divide into three portiona.
Test for
Ou hy AmHO ; blae 80I.
Hg (mercuric) by Ou;
globules.
PbbyH^SO,; white ppt.
* Llqnida containing only a small ciuantity of lead do cot readily yield snlphate of lead on the addition of sulphuric acid. Before lead can he said to be absent, therefore, the liquid should he evaporated to dryness with one drop of sulphnric acid, and the resiilue digested ID water; any sulphate of lead then remiiius as a heavy white in- aoluble powder.
id .y Google
|
E COMMON METAL. |
|
|
tiW. |
ill! |
|
5.3 s° |
|
|
^IssS |
"•lis |
|
si&^^ |
|
|
ii.A< |
J'S^SI |
|-a>?lt
cS^M <i .a s
M e^ <1 E^ a mW g
Hosled^y Google
S3
|
THE |
METALLIC |
RA |
DIOA |
LS |
|||
|
.;'=;! lis-- |
|||||||
|
.« |
|5E"lBS|.^g |
||||||
|
s!^'- |
M-j-iyS -g |
||||||
|
Ss-'s |
«£s;-hSM |
||||||
|
as |
|||||||
|
ii |
A"*^ |
|i| |
|||||
|
= ,3?o |
|||||||
|
m1 |
B.-0, |
i |
I4« |
||||
|
1 |
^s'w |
"° |
&-g |
||||
|
f- |gM' |
rg |
||||||
|
^S |
i^g |
||||||
|
Sa |
^s |
||||||
|
s^ .^S' |
S< |
. Hi |
§5!= |
3 "Sit |
|||
|
m |
'11 |
I^tl |
|||||
|
1 |
^^ |
£ &" |
|||||
|
ili-l!l!l |
|||||||
|
51 |
g ^^|3=^S| |
||||||
|
llf |
h'.iM. |
||||||
|
s |
el" |
i!i«i |
a s^liii |
||||
|
2^« Is! |
lii |
1^1 II3 ^ 0 og |
|||||
|
"^^1 s |
ii:flr!iifliiit |
||||||
|
1 |
^mm^^ |
||||||
|
A |
ks |
111 |
|||||
|
a "o-s. |
|||||||
|
iSgs |
I.^sllfl |
||||||
|
a^5 |
o" |
||||||
|
Ig |
■ 'w-0 |
a w»^- |
|||||
|
I i^ |
|||||||
|
■s |
a. 3 |
Fit |
|||||
|
£ |
fl s |
" |
Hosled^y Google
COMMON ME
|
HCl |
H^ (AmHS |
Am,CO, |
Ani^HAsO, |
|||
|
He |
Cu |
. |
Zn |
Ba |
Mg |
K |
|
Pb |
,3. |
is |
Al |
Oa |
Na |
|
|
As |
Aa Sb |
ll |
Fe |
Am |
The practical student sliould examine solutions containing the above metals until lie ia able to analyae with facility aad acenraoj. In this way lie will best perceive the peoaliarities of each element and their general relations to each othei". As the rarer metals are not included here, the tables are hot complete analytical schemes ; further remarks concerning them, therefore, are for fie present deferred.
QUESTIONS AND EXERCISES.
323. Give precedes for the qualitative analysis of liquids coutain- ing the following substances; —
a. Antimony and Mercurous salt.
b. Lead and Calcium.
c. Silver and Mercnrous salt.
d. Lead and Mercuric salt.
e. Copper and Arsenicum. /. Arseuicnm and Antimony.
a. Aluminium and Zinc.
ft. Iron and Copper.
i. Magnesium, Calcium, and Potassium.
j Silver, Antimony, Zinc, Barium, and Ammonium.
324. Enumerate the so-called group-t«sts.
325. Give a general sketch of the method of analyzing a solution suspected to contain two or more salts of common metals.
326. Classify the common metals according to their analytical relations.
id .y Google
EARBR MET
METALS OP MINOR PHARMACEUTICAL IMPORTANCE.
Thus far has been considered, somewtiat in detail, the clieniistry of the commOQ metals, Baits of which are frequently uaed io medicine or in testing medicinal substances. These are : — Poti^sium, Barium, ^ Zine, Arsenicum, Mercury,
Sodium, Calcium, Alniaiainm, Autimony, JjQ&d,
Ammonium (?) Magnesium, Iron, Copper, Silver.
There still remain eleven metals, eight of which are mentioned in the British Fharmacopceia, namely : —
Lithium, Ohroiaium, Gold, Cadmium,
Manganese, Tin, - Platinum, Bismuth.
Compounds of the remaining three are eufBcieutly comniou to occa- sionally come under notice ; — ■
Strontium, Oohalt, Nickel.
These eleven metals of minor pharmaceutical interest may he shortly studied, a few only of the reactions of each (just those men- tioned in the following pagesj heing performed. "When all have been thus treated, their respective positions in the analytical groups ■will be indicated and a taoular scheme by which an analysis of a solution containing any metal may be effected. Thus, step by step, we may learn how to analyze almost any substance that may occur, and huow to what extent the presence of a rarer will interfere with the ordinary tests for a common element: additional illustrations of the working of chemical laws will be acquired, and the stflre of chemical and pharmaceutical facts inereaaed. The opportunity thus afforded for improvement in habits of neatness in manipulation, pre- cision, and clarification is another and no mean reason why such experiments should be prosecuted, the direct value of which may not be considerable.
LITHIUM.
Symbol L. Atomic weight 1,
Lithium is widely distributed in nature, but usually in minute pro- portions compared with other elements. A trace of it may be found in most soils and waters, a OomiBh spring containing even consider- able quantities as chloride.
One salt used in medicine ia the Citrate (LjCjH^O,) {L/ithii^ Ojiras, B.P.), occurring in white deliquescent crystals or powder, prepared by dissolving 50 grains of the Carbonate (LjCOa) and 90 of citric acid in 1 ounce of water, evaporating to a low bulk and
id .y Google
aettinjf aside in a dry place to crystallize dryness and powdering tie residne.
The carbonate (lAthicB Oarbonas, B. P. and TT. S. P.) is a white grannlar powder obtained from the minerals which contain lithium; namely, lepidolite (from \iwU, l&pis, a scale, and aBoj, Uthos, a stone ; it has a Bcaly appearance), tnphane (from Tpi«, treis, three, and ipalrx phamB, I shine), or spodnmene (from imoSioo, spodoS, to reduce to ashes, in allusion to its exfoliation in the blowpipe-flame), and petalite (from irhaxm, petalon, a leaf; its character is leafy and lami- nated). Bach contains silicate of alamininm, with fluoride of potas- sinm and lithium in the case of lepidolite, and silicate of sodinm and lithium in the others. Liquor Ltthice lifervesmrts, B. P., is a solu- tion of 10 grains of carbonate of lithium in 1 pint of water charged with 1 times its volume of carbonic acid gas and kept in ordinary aBcated water-bottles. " Half a pint, evaporated to dryness, yields 5 grains of a white solid residue, answering to the teste for carbonate
of lithium Ten grains of the latter salt neutralized with aal-
phnric acid, and afterwards heated to redness, leave 14.86 grains of dry sulphate of lithium, which, when redl^olved in distilled water, yields no precipitate with oxalate of ammoniura or solution of lime," indicating absence of salts of calcium and aluminium. Citrate of lithium Bttonld yield by incineration 52.8 per cent, of white carbo- nate of lithium.
Urate of Uthiv/m* is more soluble than urate of sodinm ; henco lithium preparations are admioistered to gouty patients in the hope that urate of sodinm, with which such systems are loaded, may be converted into urate of lithium and romoved.
In cAe»wca2j)DS8V*'omJithium stands between the alkaline and the alkaline-earth metals, its hydrate, carbonate, and phosphate being slightly soluble in water. Its atom is univalent, L'. ■■
Analytioal Reaction. — Moisten tbe end of a platinum wire with solution of a minute particle of solid lithium salt, and introduce it into the flame of a Bunsen burner or other slightly colored flame (spirit-lamp or blowpipe- flame) ; a magniflcfint crimson tinge is imparted.
Tho light emitted by ignited lithium vapor is of a purer scarlet than that given by strontium, the next clement. When the flames are examined by spectral analysis (physically analjeed by a prism), the red rays are, in the case of strontium, found to be associated with blue and yellow, neither of which is present in the lithium light,
* Urates will be considered subsequently in connection with uric acid.
id .y Google
STRONTIUM.
Symbol Sr. Atomic weight 87.5.
Sovrce. — Sti'ontinm is not widely diatribnted in nature; but the carbonate (SrOO,), known as Btrontt«mte, and the sulphate (SrSO,), tnown as celesttne (from ccdum, the sky, in alluaion to its occasional blnish color), are by no means rare minerals.
Salts of itvtyaiiwm, are not employed in medicine. They are chiefly used by firework manufacturers in preparing red fire. The color they impart t* flame is a beaotiful crimson — i^ited strontium vapor emitting red rays, as already explained. Nitrate of strontium (Sr2N0,) is best for pyrotechnic compositions, its oxygen enabling it to bum ft'eelj when mixed with charcoal, sulphur, &c. It, or any Halts, may be obtained by dissolvina; the carbonate in the appropriate acid, or by igniting the cheaper sulphate with coal, whereby sulphide (SrS) is produced, and dissolving this in acid.
Th« positioji of strontium, among the chemical elements is between barium and caloiam ; its sulphate is very sparingly soluble in water. Its atom, like those of barium and calcium, is bivalent (Sr").
Analytical MeacHons ( Tests).
First Analytical SeacUon. — To solution of a strontium salt {Sr2N0, or SrCl,) add carbonate of ammonium ; a white precipitate of carbonate of strontium (SrCO,) falls.
Second Analytical Beaction. — To a solution of a stron- tium salt add sulphuric acid previously so diluted that it will not precipitate calcium salts or an equally dilute solu- tion of any other sulphate ; a white precipitate of sulphate of strontium (SrSO^) falls. The formation of this pre- cipitate is promoted by stirring and by setting the liquid aside for some time.
Barium is precipitated immediately under similar circumstances.
Third Analytical Beaction. — To a dilute solution of a strontium salt add yellow chromate of potassium ; no pre- cipitate falls.
Bariam may be separated from strontium by chromate of potas- sium, that reagent at once precipitating barium from aqueous or acetic solutions.
Fourth Analytical Seaction.~~lTis&rt a fragment of a strontium salt in the blowpipe-Same, or other equally colorless flame, or hold the end of a platinum wire dipped into a strontium solution in the flame ; a crimson color is imparted.
Other Analytical Eeactions. — Alkaline phosphates, arse- niates, and oxalates give white insoluble precipitates witb
id .y Google
STRONTIUM — MANGANESE. 185
strontium as with barium and calcium. Strontium, like
calcium, but unlike barium, is not precipitated by hydro- fluosilicie acid.
Cbkidk. Oe. At. wt 22. — This element occurs in the mineral cerile (a silicate of iron, calcium, and the three rare metals, cerium, lanthaniam, and didvmitiiQ) ; also occasionally as impure fluoride, carbonate, and phosphate. The oxalate of cermm, a White granular powder, is the only official salt ; it may be obtained from cerite by boiling the powdered mineral in strong hydrochloric acid for seyerd hoars, evaporatiug, diluting, and filtering to separate silica; adding ammonia to precipitate hydrates of all the metals except calcium ; filtering off, washing, redissolving in hydrochloric acid, and adding oxalic acid to precipitate oxalate of cerium. The preparation will still contain oxalates of lanthaninm and didyminm ; it is therefore Bti'ongly calcined, the resulting oxides of lanthaninm and didjrainm dissolyed out by boiling with a concentrated solution of chloride of ammonium, the residual oxide of cerium disolved in hydrochloric acid, and oxalate of ammonium added tx) precipitate pure oxalate of cerium (Oe"0jO4, 3H,0).
Oxalate of cerium (Cerii Ooiolas, B. P.) is decomposed at a dull red heat, a salmoitcolored mixture of oxides remaining ; nsually a little didyminm is present, giying the ignited residue a reddish- brown color ; it is then soluble in boiling hydrochloric acid (without efferrescence ; indicating, indirectly, absence of earthy and other carbonates or oxalates), and the solution gives, with excess of a saturated solution of sulphate of potassium, a crystalline precipitate of double sulphate of cerium and potassium. Alumina mixed with oxalate of cerium may be detected by boiling with solution of potash, filtering, and adding excess of solution of chloride of ammonium, when a white ioccnlent precipitate of hydrate of aluminium will he
ash Bolntion by acetic acid and adding chloride of calcinm ; t oxalate of calcinm is then precipitated; this precipitate though in- soluble in acetic, should be wholly dissolved by hydrochloric a,cid.
SIASQANESE.
Symbol Mn. Atomic weight 55.
Source. — Manganese is a constituent of many minerals, and as black oxide (MnO,) Manganesii Oxidwm Nigrum, B. P. and U. S. P.), or pyrolustte (from rtSp, pwr, fire, and j-ijots, lusis, a loosing or resolving, in allusion to the readiness with which it is split up by beat into a lower oxide and oxygen), occurs frequently in abundance in the southwest of England, Aberdeenshire, and moat of the countries of Europe.
The chemical vosition of manganese is close to iron and three other metals still to be considered..— cobalt, nickel, and chromium, lis atom apparently has sexivalent affinities, as seen in manganate of potassium (K^MaO,) ; but commonly it is quadrivalent (Mn") or bivalent (Mn").
id .y Google
Uses. — Metallic manganese ia onlj used in alloj with iron in the mannfactore of some varieties of 9l«el. The black oxide is an im- portant agent in the production of chlorine, the preparation of green and red disinfecting manganates, purple glass, and black glazes for
c Analytical Interest,
First Reaotion Boil a few grains of black oxide of
manganese with some drops of hydrochloric acid until chlorine ceases to be evolved ; add water, and filter ; the filtrate is a solution of manganous chloride (MnClo). MnO, + 4HC1 = MoCl, + 2H^0 + 01^.
This is the reaction commonly applied in the preparation of chlo- rine gas. It ia also a ready method of preparing a manganous salt for analytical experiments. Coupled with the application of reagents to the flltral*, the reaction ia that by which a black powder or mine- ral would be recognized as black oxide of manganese.
Second Beaction. — Heat a particle of a manganese com- pound with a grain or two of carbonate and hydrate of potassium and a fragment of nitrate or chlorate of potas- sium on platinum foil in the blowpipe-flame; a green mass containing manganaie of potassium (K^MnOJ results. Boil the foil in a little water ; the green manganate dis- solves and soon changes to solution of the purple perman- ganate of potassium (KjiMnaOj).
This is a delicate analytical teat for manganese.
The reaction is similar to that by which permanganate of potas- sium (Potassis Permanganas, B. P. and U. S. P.) is directed to be prepared for use in volumetric analysis. LiqiKir Fotassce Perman- ga/itatia, B. P., ia a solution of 80 grains of permanganate of potas- sium in 1 pint of distilled water. Equations showing the exact a«tion which occurs in making the salt according to the process of the British Pharmacoposia have already been given in connection with the compounds of potassium (vide p. 53). The proportions of ingredients and details of the operation are as follows ; —
Eeduae 3i parts of chlorate of potassium to fine powder, and mix it with 4 of black oxide of manganese ; put the mixture into a porcelain basin, and add to it 5 parts of solid caustic potash, pre- viously dissolved in 4 parts of water. Evaporate to dryness, stirring diligently to prevent spirting. Pulverize the mass, pat it into a covered Hessian or Cornish crucible, and espose it to a dull red heat for an hour, or till it has assumed the condition of a semifiised mass. Allow to CDol, pnlveriw. aud boil with about 30 parts of water, I-et the iQBolabie matter sulfide, decant the fluid, boQ again with about 10 parts of water, again decant, neutraliae the united liquors accn-
id.y Google
MANGANESE. 18t
rately with diluted sulphuric acid (or, better, carbonic acid gas), and evaporate till a pellicle forniB. Set aside to cool and crystallize. Drain the crystalline mass, boil it in 6 parte of water, and strain through a funnel the throat of irhich is lightly obstructed by a little asbestos. Let the fluid cool and crystallize, drain the dark purple plender prismatic crystala, and dry them by placing under a bell jar uver a vesBel containing sulphnric acid.
Instead of converting the manganate into permanganate by ebul- lition, by which one-third of the manganese is lost, Stadeler recom- mends chlorine to bo passed through ^e cold solution until the green color is entirely changed to purple.
Solutions of the manganates of potassium are in common use as disinfectants under the name of Oondy's fluid. They act by oxidiz- ing organic matter, the manganic or permanganic radical being re- duced to black manganic oxide, or even a lower oxide.
The changes in cwoT which the green mass of the above process undergoes when dropped into warm water procured for it the old name of 'mineral chwmelion,
' Third Eeaciion. — Make a borax bead by heating a frag- ment of the salt on the looped end of a platinum wire in the blowpipe-flame until a clear transparent globule is ob- tained. Place on tlie bead a minute portion of a manga- nese compound, or touch it with a drop of solution. Again fuse the borax ; a bead of a violet or amethystine tint is produced.
This is a good analytical reaction. It has also synthetical interest, illustrating the use of black oxide of manganese in producing com- mon purple-tinted glass.
Expose the bead to the reducing part of the flame, the part nearer to the blowpipe, where there are highly lieatcd hydro-carbon gases greedy of oxygen ; the color disappears.
This is owing to the reduction of the manganic compound to a manganous condition, in which it no longer possesses peculiar color- ing-power. This action also illustrates the use of black oxide of manganese in glass-manufacture. Glass when first made is usuall* of a green tint, owing to the presence of ferrous impurities ; the addition of manganic oxide to the materials converts the ferrous into ferric compounds, which have comparatively little colorific power, it itself being thereby reduced to manganous oxide, which also gives but little color. If excess of manganic oxide be added, a purple tint is produced.
Fourth Reaction. — Through a solution of a manganous salt acidified by hydrochloric acid pasa snlphuvetted hydro- gen; no decomposition occurs. Add ammonia; the sul- phydrate of ammonium thus formed causes the precipitation
id .y Google
1n8 rarer metallic radicals.
of a yellowish pink or flesli-tinted precipitate of manganoua sulphide (MnS) in a hydrous state.
This rea«tiou is characteristic, snloiiide of manganese being tiie only flesli-colored snlphide knowB. The salt need maj be the mauga- noaa cloride obtained in the first reaction ; bat such crude solntiotis usually give a black precipitate with sulphjdrate of ammoninni, owing to the presence of iron. The latter element may be removed, however, on boiling the maDganons solutioa with a little cai'bonato of sodium, which tiirows the ferric salt out of solution before the manganouB. Pwre manganous chloride may be similarly obtained ou boiling the impure solution with manganous carbonate; the latter decomposes the ferric chloride with production of ferric hydrate and more manganous chloride, and evolution of carbonic acid gas.
To the recently precipitated manganous anlphide add acetic acid ; it is dissolved.
This solubility enables manganese to bo separated from nickel, cobalt, and zinc, whose sulphides are insoluble in weak acetic acid. To express the fact in another way — manganese is not precipitated by sulphuretted hydrogen from a solution containing free acetic acid only.
Fifth Reaction. — To solution of manganous salt add ammonia drop by drop ; a white precipitate of manganous hydrate (MnSHO) falls. Add excess of ammonia; the precipitate is dissolved.
The fixed alkalies give a similar precipitate insoluble in excess. The precipitate rapidly absorbs oxygen, becomes brown, and gradu- ally passes into a higher oxide.
Sixth Reaction. — Heat a little black oxide of manganese in a test-tube with sulphuric acid ; oxygen is evolved and aulphateofmanganeseformed(JfffinffaneSMSwipAas,U.S.P.), add water, boil, filter, evaporate and set aside to crystallize. Larger quantities are made in a similar manner.
Sulphate of manganese (MnS0„5H,0) occurs in colorless, or pale rose-colored, transparent crysbJs, which, when deposited from a solution at a temperature between 68° and 86°, have the form of right rhombic prisms, and contain four molecules of water. This salt is very Bolnble in water. The solution is not colored by tincture of Dutgall a black (a t>lack shows iron), but affords with caustic alkalies a white precipitate' (Mn2H0), which, by exposure to the air, soon absorbs oxygen, and becomes brown. Suljmydrate of ammonium thi'ows down a flesh-colored precipitate (MuS), and ferrocyanide of potassium, a white one (MnFcy).
Many other reactions occur between manganese salts and various reagents, but are of no particular synthetical or
id .y Google
COBALT. 189
analytical interest. A good method proposed by Crom, for detecting minute quantities of manganese consists in add- ing diluted nitric acid and the puce-colored oxide or per- oxide of lead to the solution, and then boiling ; a red tint, due to permanganic acid, is imparted to the liquid.
COBALT,
Symbol Co. Atomic weiglit 58.8.
Source. — -Cobalt occurs sparingly in nature as the arsenide (CoASj), or tiiirwhtte cohali, and occasionally as a doable arsenide and sul- phide (OoASj, Co8j), or cobalt-glance (from glann, brightness, in allnsion to its lustre),
Uses. — Its chief use is in the manufactory of blue glass, the color of which is dne to a compound of cobalt. Cobalt is also the coloring coBBtituent of smalf (from smelt, a corruption of melt), a finely-groand sort of glass used as a blue pigment by paper-stainers and othera. and employed also by laundresses to neutralize the yellowish appearance of washed linen.
TIte Baits of cobalt may be obtained from the oxide (OoO), and the oxide from zaff're, & mixture of sand and roasted ore.
QiiaTttivalence.—Oohaii often eshibita quadrivalent affinities, but Btillmore often exerts only bivalent powers (Co"). It has analyti- cal relations with ainc, nickel, and manganese, and may he regarded as a member of the iron group.
Analytical Reactions ( Tests).
Mrst Analytical Reaction. — Pass sulphuretted hydi-ogen through a solution of a salt of cobalt — the chloride (CoClj) or nitrate (Co2NO,) for example ; no decomposition occurs. Add ammonia ; the sulphydrate of ammonium thus formed causes the precipitation of black sulphide of cobalt (CoS).
The moist precipitate slowly absorbs oxygen from the air, becom- ing converted into sulphate of cobalt (O08O,),
Second Analytical Reaction. — Add ammonia gradually to a cobalt solution ; a blue precipitate of impure hydrate of cobalt (Co3H0) falls. Add excess of ammonia ; the pre- cipitate is dissolved.
A similar precipitate is given by the fixed alkalies, insoluble in
Third Analytical Reaction — Make a borax bead by heat- ing a fragment of the salt on the looped end of a platinum wire in a blowpipe-flame until a clear transparent globule is obtained. Place on the head a minuto portion of cobalt
id .y Google
compound, or touch it with a drop of solution. Agsiin, fuse the boras ; a blue bead results.
This is a delicate test for oobait. From ivliat has previously been said, it will be seen that this experiment has also considerable syu- thetical interffit
Fourth Analytical Beaction. — To a solution of a salt of cobalt add two or three drops of hydrochloric acid, then excess of solution of cyanide of potassium, and boil for ten minutes; oxygen is absorbed, and cobalti cyanide of potassium (KjCoCyB) formed. Add hydrochloric acid, and boil the mixture (in a fume-cupboard, to avoid inhalation of any hydrocyanic acid) ; the excess of cyanide of potas- sium is thus decomposed, but the cobaltieyanide ia un- affected. Now add excess of solution of i»otash ; tlie cobaltieyanide of potassium is decomposed, the hydrate of cobalt formed remaining dissolved iu the alkaline liquid.
Nickel nnder similar circumstances is precipitated, the reaction thus affording means of separating these closely allied metals from eaoli other.
Other reactions between a cobalt solution anddifferent reagents may be performed, and various precipitates ob- tained ; but these have no special analytical interest.
Invisible Ink. — The salts of cobalt containing water of crystallization are light red, the anhydrous more or less blue. Prove this by writing some words on paper with a solution of chloride of cobalt sufficiently dilute for the characters to be invisible when dry ; hold the sbeet before a iire or over a flame ; the letters at once become visible, distinct, and of a bine color. Breathe on the words, or set the sheet aside for a while ; the characters are once more invisible, owing to absorption of moisture. Hence solu- tion of chloride of cobalt forms one of the so-called sym- pathetic inks.
NICKEL.
Symbol Ni. Atomic weight 08.8.
Nickel is, chemically, closely allied to cobalt, the ores of the two metals being commonly associated in uatnre. Indeed it is from epeiss, an arsenio^nlphide of nickel obtained in the mannfactiire of smalt, a pigment of cobalt already mentioned, that most of the nickel met with in commerce is obtained. It is much used in the preparation of the white alloy known as German or nickel silver.
id .y Google
§«««iit)aiewce, — Niokel eserts bivalent aotiTity (Ni") in its ordi- nary compounds. Its salts and their solutions are iisimlly grrcn. Thuy are chieHy made, directly or indirectly, from the metal itself.
Analytical Meactions { Tests).
Mrst Analytical Reaction. — Pass sulphuretted liydrogeii tlivough a solution of a salt of nickel — chloride {KiClJ, nitrate (NiSXOJ, or sulphate (NiSO,) ; no decomposition occurs. Add ammonia; the sulphj-drate of ammonium thus formed causes the precipitation of black sulphide of nickel (XiS).
Note. — When snlphide of nickel is precipitated by tlie direct addition of the common yellow solution of sulpiijdrate of ammoniuni, irliich always contains sulphur, thoro is much diificulty in filtering' the raisture, owing to the slight solubility of the sul]ihido of niekcl in the reagent and tho foi-matiou of some sulphate of mckel {NiSO,,}, oxygen being absorbed from the adr by the sulphide. This may be avoided by warming the mixture and using freshly-made sulphydrato of ammonium, in which the snlphide of nickel is insoluble ; or, nhero practicable, the salt of nickel may be precipitated from an ammo- niacai solution by sulphuretted hydrogen.
Second Analytical Beaction. — Add ammonia drop by drop to a nickel solution; a pale-green pi-ecipitafce of hydrate of nickel (Ni2HO) falls. Add excess of ammonia; the pre- cipitate dissolves.
A similar precipitate is given by the fixed alkalies, insolu- ble in excess.
Third Analytical Beaction. — Nickel salts color a borax bead, when hot, a reddish-yellow tint; the reaction is not very serviceable analytically.
Fourth Analytical Beaction. — To a solution of a salt of nickel add solution of cyanide of potassium ; cyanide of nickel (NiCy,) is precipitated. Add excess of solution of cyanide of potassium; the precipitate is dissolved with formation of double cyanide of nickel and potassium (NiCyj,2KlCy). Next add hydrochloric acid, and boil the mixture (in a fume-cupboavd), adding a little hydrochloric acid from time to time until all smell of hydrocyanic acid has disappeared. Lastly, add excess of solution of potash ; hydrate of nickel is precipitated.
This reaction serves for the separation of nickel from cobalt. On adding excras of hydrochloric acid to a solution containing the two metals, tog-ether ivith cyanide of poiassium, a, precipitate of cyanide of nickel and cobalticyaiiide of nickel occiu's. By ebullition willi
id .y Google
192 BARER METALLIC RADICALS.
e\ e of ]iy Iro 1 ] r t. id tl e r an ie o k I Je com posed,
clil ride of nickel going into solation On then adding excess of potash hydrate of nickel is piccipitated The cohalticvanide of nic! el IS not decomposed by the acid hut it n by the alkali, its cclalt going into solution and ita nickel remaining insolnble as hjdnte
After filtenng off the nickel cobalt is detected in the flit ate by eiaporating to dryness and testing the residue with bon,\ in the blowp pe-flame
Other reactions between a nickel solution and various i-eagents give, in many cases, insoluble precipitates wliicli, from their green color, are occasionally useful in distin- guishing nickel from allied elements.
CHKOmiUlH.
Symbol Cr. Atomic weight 52. 5.
Soiwce.— The chief ore of chrominm is chrome ironstone, a mix- ture of the oxidee of the mefals (FeO, Cr^O,), occurring chiefly in the United States and Sweden.
Preparation of Red Ckromate of Pctassiwm. — On fusing the powdered ore with carbonate of potassium and nitre, yellow chn> mate of potassium (K^CrO^) is obtained; the mass, treated with acid, yields red or bichromate (K!,0r04, OrO,) (Potassce Bichromas, B. P. and U. S. P.) ; from this salt other chromates are prepared, and by reduction, as presently explained, the salts of chromium itself. The yellow and orange chromates of lead are largely used as pig- ments.
Note on Constitution. — Red chromate of potassium is a somewhat abnormal salt, containing, probably, neutral chromate associated with chromic anhydride ; it seems to be analogous in constitution to borax and some other compounds. The value of chromates as chemical reagents is alluded to in connection with chromate of barium (p. 76). Heated strongly in a crucible, red chromate of potassium splits up into yellow chromate, glistening oside of chromium, and oxygen.
Quantivalence. — Chromium stands in close chemical relation to iron, aluminium, and manganese. Its atom is sexiralent if the for- mula of the fluoride (CrFj) be correct. Like iron and aluminium, it is triTalent, as seen in chromic chloride (OrjOlji, bnt sometimes ex- erts only bivalent activity, as in chromous chloride (OrOl,).
Passage of chromium from the acidulous lo the basylous side of salts. — Through an acidified solution of red chro- mate of potassium pass sulphuretted hydrogen ; sulphur is deposited, and a green salt of chvomium remains in so- lution— chloride (Or,CIa) if hydroehlorie acid be used, and sulphate (Or^SSOj) if sulphuric be the acid employed. Boil the liquid to expel excess of sulphuretted hydrogen, filter, and reserve the solution for subsequent experiments.
id .y Google
OIIIiOMlUM. IVo
Alcohol, sngar, or almost any substance wliicli is tolorablj- liable to osidation will answer as well as sulphuretted hydrogeiv.
Sulphate of chromium (CrjSSOJ, like snlphate of alnmiuium (Alj3S0^), unites with alkaline sulphates to form alums, which re- Bomblc commcm alum both in crystalliue form and, as fa.r as no know, in internal structure : they are of a purple color.
Ebactioxs.
Chromium as chromic acuJ^ or other chromate. — This is tlie state in which chromium will usually be met with, the most common salt being the red chromate or bichromate of potassium. Mix four volumes of a cold, saturated aqueous solution of red chromate of potassium with five of oil of vitriol; on cooling, chromic anhydride (OrO,), aoidum chromium, TJ. 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. In contact with moisture chromic anhydride takes up water and forms solution of true chromic acid (H^CrOJ. Chro- mic anhydride is a powerfully corrosive oxidizing agent. It melts between 356° and 374°.
The oxygen ia chromic acid and other chromates, and in mang^n- atcs, permanganates, black oxide of manganese and puce colored oxide of lead is in a physically dilferent state to that iu peroxide of hydrogen, peroxide of barium, and similar compouada. On bringing chromic acid or the above acidified solution of red chromate of po- fassinm into contact with solution of pcroside of hydrogen a strong effervescence of oxygen ensues. According to SchBnbem and Brodie the oxygea of chromic acid is in the negative or ozonio state, while that of peroxide of hydrogen is ia the positive or antozonic condition. Both are equally active, but neutralize each other formiug neutral or ordinary oxygen.
In the analytical examination of solutions containing chromates, the chromium will always come out in the state of green chromic hydrate along with ferric hydrate and alumina, the prior treatment by sulphuretted hydrogen re- ducing the molecule to the lower state, thus :—
K,CrO,, CrO, + 8HC1 + 3H.S = Cr.Cl, + 2EC1 + 7H,0 4- Sj.
Chromium having been found in a solution, its condition as chromate may be ascertained by applying to the original
n
id .y Google
L Lie RADICALS
soUition salts of barium, mercury, lead, and silvci the various paragraphs relating to those mctals.J
|
Ba2N0, gi |
ves yellow EaCrO, with chromatcs. |
|
H-3NO3 ' |
' red Hg^CrO, " |
|
A|ko, ' |
' red AgjCrO, " |
|
" i |
' " Ag.,OrOj, OrO,with bicliTOmates. |
|
PbSCjH^O, ' |
' yellow PbCrO^ with both. |
Nitrate of barium does not completely precipitate bichromates, bichromate of barium being soluble in water ; the chromate of barium is insoluble in wafer or acetic acid, but soluble in hydrochloric or nitric acid. Jfercnrous nitrate does not wholly precipitate bichro- mates : mercuric nitrate or chloride only partially precipitates chro- mates, and does not precipitate bichromates. The mercurons chro- mate is insoluble, or nearly so, in diluted nitric acid. Acetate of lead precipitates chromates and bichromates, acetic acid being set free in the latter case. The silver chromates are soluble in acids and alkalies.
A delicate reaction for dry chromates will be found in the formation of chlorochromic acid (CrOjClJ. A small portion of the chromate is placed in a test-tube with a frag- ment of dry chloride of sodium and a drop or two of oil of vitriol, and the mixture heated ; red instating fumes of chlorochromic acid are evolved, and condense in dark red drops on the side of the tube.
Large quantities of pure distilled chlorochromic acid are ohfaiticd by the same reaction, the operation being conducted in arclort, nilh thoroughly dry materials. It may be regarded as chromic iiiilLy(lii<lp in which an atom of oxygen is displaced by an equivalent qiiuiUity (two atoms) of chlorine. It is not used in medicine, but is of interest to the chemical stndent as being an illustration of a large class of similar bodies — chloro-aciduloits compotmds.
Analytical Reactions of Chromium Salts (Tests).
First Analytical Meaction. — To solution of asalt of chro- mium (chloride, sulphate, or chrome alum) add sulphydrate of ammonium ; a bulky green precipitate of chromic hy- drate (Crj6H0), containing a large quantity of water (T molecules, THjO), is precipitated.
Cr.Cls + 6AmHS -I- 6H,0 = Cr,6H0 + OAmCl -f fiH^S.
Second Analytical Reaction^— "Vo solution of a chromium salt add ammonia ; chromic hydrate is precipitated, insolu- ble in excess.
id .y Google
TIN. 195
Third Analylical SeacHon. — To solution of a cbromimn salt add solution of potash or soda drop by drop ; chromic hydrate is precipitated. Add excess of the fixed alkali; the precipitate is dissolved. Well boil the solution ; the chromic hydrate is repreeipitated.
Iron, Ghromiitm, and Altfminium Salts, cheiuicallj so alike, nifiy be separated by this reaction. Ferric hjdi-ato is insoluble in solu- tions of the fixed alkalies, cold or hot; cnromium hydrate solnhle in cold but not in hot ; hydrate of alununiTun in both. To a Bolntion containing all three metals, therefore, add potash or soda, stir, and Alter ; the iron is thrown oat : boil the filtrate, and filter : the chro- mium ia thrown ont ; neutralize the filtrate by acid, and then add ammonia ; the alnmininm ia thrown ont. The three liydrates are insoluble in amnionin, and may therefore be easily separated from the hydrates of the somewhat analogous metals zinc, cobalt, nickel.
Fourth Analytical Reaction. — Add a salt of chromium (either of the above precipitates of chromic oxide or the dry residue of the evaporation of a few drops of a solu- tion of a chromium salt) to a few grains of nitre and car- bonate of sodium on platinum foil, and fuse the mixture in the blowpipe-flame; aj'ellowmasa of chromate of potas- sium and sodium (KlVaCrO,) ia 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 useful reaction if carefully per- form od.
Symbol Sn. Atomic weight 118.
Source. — The chief ore of tin is stannic oxide (SnO^J, occnrring in veins under tlie name of tinstoiie, or in allavial deposits as stream- tin. The principal mines are those of Cornwall.
Preparaiz'oJi.— The metal is obtained by reducing the roasted and washea ore by charcoal or anthracite* coal at a high temperatnre, and is purified by alowly heating, when the pure tin, fusing first, is run offf a somewhat less fusible sdloy of tin with small quantities of arsenic, copper, iron, or lead remaining. The latter is known as hhcJi: tin; the former heated till brittle and then Immmered or let fall from a height splits into prismatic fragments resembling starch
*■ AitlhraciU (from hSfa^, anthrax, a burning ooal) or stone coal differs from tlie oi'dinarj bitaminoua or caking coal, in containing less Toliitile mutter, and, therefore, in burning without flame. It gives a higher tciiipernture. and from its non-oaking properties if, in furnace operations, more manageuble than bitumioous coaL
id, Google
196 RARER METALLIC RADICALS.
or ba?alt, and is named dropped or grain tin. Good tin emits a. criMikling noise in bending, termed the cry of tin, caused by tl\e Mc- tion of its crystalline particles on eaci otlier.
Dfifis.— Till is an important constitnent of Bach alloys as peTiler, Britannia metal, solder, speculum-metal, bell-metal, gun-metal, and bronze. It B very ductile, and may be rolled into plates op leaves, known as tin foil, varying from jjj to toVf **f ^^ inch in thictncBB. Common tin foil, however, nsiially contams a large proportion of lead. The reflecting surface of most looking-glasses is an amalgam of tin and mercury, produced by carefully sliding a plate of glass over a sheet of tin fori on which mercnry has been mbbed, and then excess of mercury poured. Pins are made of brass wire on which tin is deposited. Tin plate, of which common utensils are made, is iron alloyed with tin by dipping tlie eleansed sheet into melted tin. Tin tacks are in reality tinned iron tacks, a tin nail would be too soft to drive intfl wood. Tin may be ffrannlated by melting and triturating briskly in a hot mortar, by shaking melted tin in ahox on the inner sides of which ehalk has been mbbed, or, in thin little bells or cor- rugated fragments (Granulated Tin, B. P.), by melting in a ladle and, B3 soon as fluid, pouring from the height of a few feet into water.
The chemical position of tin among the metals is close to that of arsenicnm and antimony. Its atom is quadrivalent and bivalent. The two classes of salts are termed stannic and stannons respectively. They are all made directly or iiidhectly from the metal itself.
Rk.iutioxs havin-(! (k) Bynthetical and (&} AxAi.yriCAL Interest.
(a) SynUielical Reactions.
Chloride of Tin. Stannous Chloride.
First Synthetical Eeaction. — Warm a fragment of tin
with hydrochloric acid ; hydrogen escapes and solntion of
stancouB chloride (SnClj) is formed. It may be retained
for future experiments.
One ounce of tin dissolved in three fluidonnees of hydrochloric acid and one of water, and the resulting solution diluted to fire Huid- ounces, constitutes the " Solution of Chloride of Tin," B, P.
Solid stannous eklortde. — By evapoi-ation of the above solution stannous chloride is obtainable in crystals {_8nCls,2H^O). It is a powerful reducing agent, even a dilute solution precipitating gold, silver, and mercury from their solutions, converting ferric and cupric info ferrous and cn^rons salts, and partially deoxidizing arsenic, manganic, and chromic acids. It absorbs oxygeo from the air, and is decomposed when added to a large (|uaLitity of water nnless some atid be present. It is used as a mordsint iu dyeing and calico-printing.
id .y Google
PeroMoride of Tin. Stannic Chloride. Hecond Synthetical Reaction. — Through a poi'tiou of the solution of the stannous chloride of the previous reaction pass chlorine gas; solution of stannic chloride (SnCl,) is formed. Or add hydrochloric acid to the stannous solu- tion, boil, and slowiy drop in nitric acid until no more fumes are evolved ; again stannic chloride results. Reserve the sohitions for subsequent experiments.
Stannic Oxide, or Anhydride, and Stannates. Third Synthetical Reaction. — Boil a fragment of tin with nitric acid, evaporate to dryness, and strongly. calcine tlie residue; white stannic anhydride (SnO,) is prodncod. Heat the stannic anhydride wit li excess of potash or soda; sUnnate of the alkali metal (E^SnO,or Na^SnO,) results. Dissolve the stannate in water, and add hydrochloric acid; white, gelatinous %tannic acid (H.SnOj) is precipitated. Stannic acid is also obtained on adding an alkali to solu- tion of stannic chloride ; it is soluble in excess of acid or alkali.
The product of the action of n'tr' ac'd ou tin 's also an ac'd hut from its insolubility in hjdroclilonc and other ac da s d ffere t f oi'diiiary stannic acid. It a te roed metasta n c ac- d(! om it -ea mcfa. bejond), and probably hi a compoB on e p e d v o fdnniila H^Bn^Oi^. It is also i odaced on ge j L u
5H,SnO = H 0
Motaatannates maybe formed the r i^ e al formn a "M I'.iitli acids yield bnff-colo ed a aun c ox 1 o anl wliiMi strongly heated; it enjloyed n p I j a
mim oi pulti/ powder. S a of s m(Na=S 4Ii used as a mordant by dye -a and cal eo-i ters e e n n tin prepare4tq)ior.
(b) Reactions having Analytical Interest { Tests).
First Analytical Reaction. — Through a solution of a stannous salt (stannous chloride, for example) pass sul- phuretted hydrogen; brown stannous sulphide (SnS) is precipitated. Pour off the supernatant liquid, add am- 17*
id .y Google
198 KAUEB. METALLIC RADICALS.
monia to the moist precipitate (to iieiitralize acid), and lastly, yellow sulpbydrate of ami on'u n th-'i recipitate ia dissolved.
Aqueous solution of sulphydrate of a no um becomes yellow when a day or two old, and then conta ns excess of sulphur, that element having become displaced by oxygen absorbed from the air ; hence, in the above reaction, the stan ous sulpl de (SnS), in dis- solving, becomes staunic sulphide (Sn& ) for the latter is precipi- tated on decomptsing the nlKaline liquid by an acid.
Second Analytical Reaction. — To solution of a stannous salt add solution of potash or soda ; white stannous hj'drate falls (Sn2H0). Add excess of the alkali ; the precipitate dissolves. Boil the solution ; some of the tin is reprecipitated as black stannous oxide (SnO).
Ammonia gives a similar precipitate, insoluble in excess. The alkaliue carbouates do the same, carbonic acid gas escaping.
Third Analytical Heaction. — Through solution of a stan- nic salt (stannic chloride, for example) pass sulphuretted Iiydrogen; yellow stannic sulphide (SnS,) is precipitated. Pour off the supernatant liquid, and to the moist precipi- tate add ammonia (to neutralize acid), and then sulphy- drate of ammoninm ; the precipitate dissolves.
Note. — In precipitating stannic sulphide the presence of too much hydrochloric acid most be avoided ; the formation of the precipifiile is also facilitated if the solution be warmed. Stannic sulphide, lilce the sulphide of arsenicum aud antimony, dissolves in solutions of any alkaline sulphide, with formation of definite crystallizable salts.
Anhydrous ttannic lulphtde, prepared by sublimation, has a yellow or orauge lustrous appearance, and is used by decorators as bro^ming'poioder. It is sometimes termed mosaic gold.
Fourth Analytical Reaction. — To solution of a stannic salt add potash or soda ; white stannic acid falls (H^SnOj), Add excess of the alkali; the precipitate dissolves. Boil the precipitate ; no repiecipitation occurs — a fact enabling stannic to be distinguished from stannous salts.
Ammonia gives a simijai precipitate, soluble, but not readily, in excess. The fixed alkaline carbonates do the same, carbonic acid gas escaping ; after a time the dtannic salt is again deposited, pro- bably as stannate of the alkili metal. Carbonate of ammonium and acid carbonates of alkali niefals give a precipitate of stannic a^id insoluble in excess.
id .y Google
GOLD. 199
Antidotes. — In case3 of poisoning by tin salts (dyers' tin liqnop B. 3-)' solntioQ of carbonate of ammonium slioiild be given. White of egg is also said to form ao iiiaoluble precipitate with compounds of tin. Vomiting should be speedily induced, and the stomach pomp qniokly supplied.
GOLD.
Symbol Au. Atomic weight 196.7
Source.— Gold, occurs tn the free state in nature occasionally m nodules or nuggets, but commonly in a finer state of division toi med gold dast.
Preparation. — Uold is separated from the sand, crushed quartz, or other earthy matter with which it may be associated, by agitation with water, when the gold from its relatively greater specific gi'avity, falls to the bottom of the vesaela first, the lighter mineral matter being allowed to run off with the water. From this rich sand tlie gold is dissolved out by mercury, the latter filtered, and the amalg-am distilled, when the mercury volatilizes and gold remains. The «mal- garaation may be much facilitated by the use of a small proportion of sodium, as described under silver.
Pure gold is too soft for general use as a circulating medium. Gold coin is an alloy of copper and gold, that of Gtreat Britain containing 1 of the former to 11 of the latter, or 8J per cent, of copper, tlmtof France, Germany, and the United States about 10 per cent Jewel- lers' gold varies in quality, every 24 parts containing 18, 15, 12, or 9 parts of gold, the alloys being technically termed 18, 15, 12, or 9 carat fine. Articles made of the better qualities are usually stamped by authority. Trinkets of inferior intrinsic worth aro commonly ihinly coated with pure gold by electro-deposition or otherwise Ofild ieof is nearly pure gold passed between rollers till it is about ji,, of an iuch in thickness and then hammered between sheets of nniraal membrane, termed gold-beatej^s skin aud calf-skin vellnm, till it is TiTp'iTiFir or Bn^'joflOf an inch in thickness. It ma^ even be hammered till 280,000 leaves would be required to form a pile an inch thick
Gold coinage. — ^The weight of gold is expressed in G-reat Britain in ounces troy and decimal parts of an ounce, and the metal is alnajs taken to be of standard flneness (11 gold and 1 alloy) nnless other- wise described. The degree of fineness of gold, as ascertained by assay, is expressed decimally, fine pure gold ("gold free frommetillic impurities, B. P.), being taken as unity, or I.OOO. Thus gold of British standard is said to he 0.9166 flue, of French standard 0.900 fine. The legal weight of the sovereign is 0.2568 onuce of standard gold, or 123.274 grains. The weight came from one pound of stand- ard gold (5760 grains) being coined into44J guineas. Sovereigns are legal tender to any amount, provided that the weight of each does not fall below 122.5 grains, or in the case of a half sovereign 61.125 grains; these are the "least current" weights of the coins.
Note.— In chemical analysis gold comes out among tlie sulphides of the metals precipitated by sulphuretted hydrogen ; and of those
id .y Google
200 It A RE 11 METALLIC RADIOAl
snlphitles, it, like the sulpliides of tin, antimony, and a soluble in sulphjdrate of ammoninm.
Quantivalence. — Gold is trivaleiit (Au'"}, but in some compounds univalent (Au').
Eeactions.
SyntJieiical Reaction. — Place a fragment of gold (e. </., goki leaf) in ten or twenty drops of aqua regia (a mixture of one part of nitric and twoor three of hydrochloric acid), and set the test-tube aside in a warm place ; solution of pevchloride of gold or auric chloi'ide (AnCy results. When the metal is dissolved, evaporate nearly to dryness to remove most of the excess of fluid, dilute with water, and retain the solution for subsequent experiments. Sixty grains of gold treated thus, and the resulting chloride dis- solved in five ounces of distilled water, constitutes " Solu- tion of Chloride of Gold," B. P. .
Au, + 2HN0, + 6HCI = 2AuC!, + 2N0 + 4H,0
This reaction liaa analjticnt interest also ; for in examining a sub- stance suspected to be or contain metallic gold, solution would liave to bo effected in the above way before reagents could be applied. Gold is insoluble in hydrochloric, nitric, and the weaker acids.
Analytical Eeaclions ( Tests).
First Analytical Reaction, — Through a few drops of so- lution of an auric salt (the chloride, AuClj, is the onjy convenient one) pass sulphuretted hydrogen ; brown auric sulphide (AUjS,) is precipitated. Filter, wash, and add eulphydrate of ammonium ; the precipitate dissolves.
Second Analytical Reaction. — Tosolutionof asalt of gold add ferrous chloride or sulphate, and set the tube aside ; metallic gold is precipitated, a ferric salt remaining in so- lution.
Tliie is a convenient way of preparing pure gold, or jina gold as it is termed, or of working up the gold residues of laboratory opera- lions. Tlie precipitate, after boiling with hydrochloric add, washing, and drying, may be obtained in a button by mixing with an eijual weight of borax or acid sulphate of potassium and fnsiug in a good furnace.
Tldrd Analytical Reaction. — Add a few drops of dilute Bolutions of stannous and stannic chloride to a consider- able quantity of distilled water ; pour the liquid, a small quantity at a time, into a dilute solution of auric chloride
id .y Google
PLATINUM
(AnCl,,), well stirring ; the mixture assumes a purple tint, and flocks of a precipitate, known as the Purple of Cassius, (from the name of the discoverer, M. Casaliis), are pro-
The same compoxind is formed on immersing a pjeco of tin foil in solution of auric chloride ; it is said ffl he a mixture of auric, aureus, stannic, and stannous oxides. It is the coloring agent in the finer varieties of ruby glass.
Sj-mlwl Ft. Atomic -n-eight 198.
So wrce.— Platinum, like gold, usually occurs in nature in the free state, the chief sources of supply being Mexico, Brazil, and Siberia. It is separated from the alluvial soil hy washing.
i/ses.— The cMef use of platinum is in the construction of foil, ■wire, crucibles, spatulas, capsules, evaporating-dishea, and stillg, for the use of the chemical analyst or manufacturer. It is tolerably hard, fnsible with very great difBcnlty, not dissolved by hydrochloric, nitric, or snlphuric acid, and only slightly affected by alkalme substances. It is attacked hy aqaa regia with production of perchloride of platinum or platinic chloride (PtCIJ. It forms fusible aliovs with lead and other metals, and with phosphorus a phosphide, wnich easily melts. Neither of these substances, therefore, nor mixtures which may yield a metal, should he heated in platinum vessels.
The chemical position of platinum among the elements is close to that of gold. Its atom is quadrivalent in some compounds, in others apparently bivalent (Pt"). The higher salts are termed ^Ja- tiaic, the lower jtZafi'iioits.
Reactioxs.
PetcMoride of Flatlnum. Flatinio Chloride.
Synthetical Reaction. — Place a fragment of platinum in a little aqua regia and set the vessel aside in a warm place, adding more acid from time to time if necessary ; solution of perchloride of platinum (PtCl,) results. Evaporate the solution to remove excess of acid, and complete the desicca- tion over a water-bath. Dissolve the residue in water and retain the solution for subsequent experiments, and as a reagent for tlie precipitation of salts of potassium and
A quarter of an ounce of platinum treated in the above manner, and the resulting chloride dissolved in five ounces of water, consti- tutes " Solution of Perchloride of Platinum," B. P.
id .y Google
203 UARER METALLIC RADICALS.
This reaction has analytical interest also ; for iu examining a substance suspected to be or to contain metallic platinum, solution would laye to be thus effected before reagents could be applied.
Analytical MeacHona ( Tests).
First Analytical Beaction. — Through a few drops of a solution of a platinic salt (PtClj is the only convenient one) to which an equal quantity of solution of chloride of sodium has been added, pass sulphuretted hydrogen ; dark brown platinic sulphide (PtSj) is precipitated. Filter, wash, and add sulphydrate of ammonium ; the precipitate dissolves.
If chloride of sodium be not present in the above reaction, the precipitated sulphide will contain platuious chloride, and detonate when heated.
Second Analytical Reaction. — Add excess of solution of carbonate of sodium and some sugar to solution of per- chloride of platinum and boil ; a precipitate of metallic platinum falls.
Platinum Black [B. P.) is the name of this precipitate. It pos- sesses in a high degree a quality common to many substances, hut largely possessed by platinum, namely, that by absorbing or occluding gases. In its ordinary state, after well washing and drying, it ab- sorbs from the air and retains many times its balk of oxygen. A. drop of ether or alcohol placed on it is rapidly oxydized, the plati- num becoming hot This action may be prettdy shown by pouring a few drops or ether into a beaker (one having portions of the t«p and sides broken off answers best), loosely covering the vessel with a card, and suspending within the beaker a platinum wire, one end being attached to the card by passing through its centre, the other termmating in a short coil or helix near the surface of the ether ; on now warming the helix in a flame and then rapidly introducing it into the beaker, it will become red-hot and continue to glow so long as there is ether in the vessel. In this experiment real combustion goes on between the ether vapor and the concentrated oxygen of the air, the products of the oxidation revealing themselves by their
Third Analytical Reaction. — To solution of perchloride of platinum add solution of chloride of ammonium ; a yel- low granular precipitate of double chloride of platinum and ammonium (PtCl„2AmCl) falls. When slowly formed in dilute solutions, the precipitate is obtained in minute orange prisms.
Chloride of potassium (KCI) gives a similar precipitate (PtOl, 2KC1). Platinic chloride haviag been stated to be a test for potas-
id.y Google
1, the reader is prepared to find tiiat riotassium
_ salts are tests for jjlatiuit salts. The double sodlmn
compound [PtC]j2NaCl) is soluble in water.
Collect the precipitate, dry, and heat in a small crucible; it is decomposed, and metal, in the finely divided state of spongy platinum, remains.
3(PtC!,2XH,Cl) = Pt^ + 2NH,C1 + 16HC1 + 2K,
Heat decomposes the potassium salt into Pt+2KC1+Cli, the chlorine esuaping and the chloride of potassium remaining with tlie platinum.
In working wp the platinum Tesidues of laboratory operations, the misture should be dried, hnrnt, boiled successively with hydro- chloric acid, water, nitric acid, water, then disBolved in aqau tegia, excess of acid removed by evaporation, chloride of ammoniam added, the precipitate washed with water, dried, ignited, and the resulting spongy platinum retained or converted into perchloride for use as a reagent for alkali-metals. It la by this process that the native plo- tiiiiira 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 a refinement ou the blacksmith's pro- cess of welding (German jueHew, to join), or by fosing in a flame of pure osy^en and hydrogen gases— the osyhydrogen blowpipe.
Occlusion hy spongy platinum. — Spongy^ platinum has great power of occlusion. X small piece held in a jet of hydrogen causes ignition of the gas, owing to tie close approximation of particles of o>:ygen (from tiie air) and hydrogen, Doberemer's lamp is con- sti'iicted on this principle — the apparatus being essentially a vessel j(i which hydrogen is generated by the action of diluted sulphuric acid on zinc, and a cage for liolding the spong'y platinum
CADMIUM.
Symbol Cd. Atomic weight 11 2.
In most of its chemical relations cadmium ( Cadmium, U. S. P.) re- sembles zinc. In nature it occurs chiefly as an occasional constituent of the ores of that metal. In distilling zinc containing cadmium, the latter, being the more volatile, passes over first. In analytical operations cadmium, unlike zine, comes down among the metals pre- cipitated by sulphuretted hydrogen ; that is, its sulphide is insoluble in dilute hydrochloric aeid, while sulphide of zinc is soluble. It is a white malleable metal nearly as volatile as mercury. 8p. gr. 8.7.
Beyond the occasional employment of the sulphide as a pigment [jaitne briUant), and the iodide in photography and medicine, cad- mium and its salts are but little used. The atom of cadmium is biviilent (Cd"),
id .y Google
Iodide of Cadmium. First Synlhetical Reaction. — Digest metallic cadmium in water in whicli a fragment of iodine is placed, until tlic color of the iodine disappears ; solution of iodide of cad- mium {Cadinii lodidum, B. P.) (Cdl^) remains. Pearly micaceous crystals may be obtained on evaporating tlie solution.
This is the process alluded to in the British Pharmacopceia. The compoand is used in medicine in the form of oiutment, Uw/uentiim Cadmii lodidi, B. P. The salt is also employed, with other iodides, in iodizinff collodion for photographic purposes. It inclfs ivhen heated, and is boIuIjIc in water or spirit, the solution raddeniiig litiims paper.
Sulphate of Cadmiam.
Second Synthetical Beaction. — Dissolve cadmium in nitric acid ; pour the resulting solution of nitrate of cadmium (Cd2N0„) into a solution of carbonate of sodium; dissolve the precipitate of carbonate of cadmium (CdCOj) in dihito sulphuric acid, separate and crystallize. Sulphate of cad- mium (CdSO,) is a white crystalline salt soluble in water, (U. S. P.)
Mrst Analytical Beaction. — Through solution of a cad- mium salt (Cdl, or CdClJ pass sulphuretted hydrogen ; a yellow precipitate of sulphide of cadmium (CdS) falls, re- sembling in appearance arsenious, arsenic, and stannic sulphides. Add sulphydrate of ammonium ; the precipi- tate, unlike the sulphides just mentioned, does not dissolve.
Snlphides of cadmium and copper may ho separated by solution of cyanide of polassium, m which sulphide of copper is soluble and sulpliide of cadmium insoluble.
Second Analytical Beaction. — To acadmium solution add solution of potash; white hydrate of cadmium (Crt31I0) is precipitated, insoluble in excess of the potash.
Hydrate of ainc (Zn2H0), precipitated under similar circum- stances, is soluble in solution of potash ; the filtrate from the hydrate of cadmium may therefore be tested for any zinc occumng as an impurity by applying- the appropriate reagent — sulphydrate of am-
Sefore the blowpipe-Jlame^ on charcoal, cadmium salts give a brown deposit of oxide of cadmium i^CilO).
id .y Google
Sjmbol Bi. Atomii; weight 208.
Source. — Bismuth occurs in the metallic state in nature. It ia freed from adherent quartz, &e., by Bimply heating, when the metal melts, runs off, aud is collected in appropriate vesgeia. It is also met with in combination with other elements, Bismnth is grayish-white, with a distinct pinkish tinge.
Uses. — Beyond the employment of some of its compounds in medi- cine, bismuth is but little Qsed. Melted bismuth expands considerably on solidifying, and hence is valuable in t«king sharp impressions of dies. It is a constituent of some kinds of type-metal and of pewter-
Tke position of bismuth among the metals is dose to that of ni«e- nioum and antimony. Its atom is rarely quinquivalent (Bie); but in roost compounds trivalent (Bi'").
(a) Reactions having Synthetical Interest.
Nitrate of Bismutli.
First Synthetical Ueaction. — To a few drops of nitric acid and an equal quantity of water in a test-tube, add a little powdered bismuth, heating the mixture if necessary ; nitric oside (NO) escapes and solution of nitrate of bismuth (BiSNOj) results.
Bi, + 8HN0, = 2(Bi3XOJ + SXO -j- iH^O
Bulh. blaianlli oxide.
The solution evaporated gives crystals (BiSNOj, SHjO), any arse- nicum which the bismuth might contain remaining m the mother- liquor. Native bkmuth [Bismuthum, B. P. and U. W. P.} commonly contains arsenicum, most of which is removed by roasting or by fus- ing two or three times with a tenth of its weight of nitre (Bismuthum Pwri^aiv/m, B. P.), or, finally, by converting the metal into oxviii- trate, as described in the next reaction, and reducing this with char- coal at a high temperature.
To make nitrate of bismuth and other salts on a larger seaie, 2 ounces of fiie metal, in small fragments, are gradually added to a mixture of 4 flnidounces of nitric acid and 3 of water, and when effervescence (dne to escape of nitric oxide) has ceased, the mixture heated for tea uiinutes, poured off from any insoluble matter, eva- porated to 2 flnidounces to remove excess of acid, and then either set aside for cTystals to form, poured into half a gallon of water to form the oteynitrate of bismuth, or into a solution of 6 ounces of carbonate 18
id .y Google
EEll METALLIC RADICALS.
„. a quart of water to form the oxycarhonate as de- scribed in the following reactions. The precipitates should be washed with cold water and dried at a temperature not exceeding 150° F. Exposed in the moist state to 212° for anj length of time, they uudcrgo slight decomposition.
Subnitrate or Oxyuitrate of Bismatli.
Second Synthetical Reaction. — Pour some of tlie above solution into a considerable quantity of water; deeompo- eition occurs and oxyiiitrate of bismuth (BiOJSfOj) in a hydrous state (BiONO^II^O) {Bismuthi Subnitras, B.F.) is precipitated : —
BiSNO, -j- H,0 = BiONO, + SHNO,
Filter, and teat the filtrate for bismnth by adding exeess of carbonate of sodium; a precipitate shows that some bismutb remains in aolutinn. Tlie following equation, therefore, probably more nearly represents the decompo- sition : — SCBiSNOJ + SHfi = 4{BiO?fO„H^O) -|- Ei3NO„8HNOa
Decomposition of nitrate of bismuth by water is the process of the British Fharmacopceia for the pieparation of oi>nitrate or sub- nitrate of bismuth for use in meditine For this puipose the original metal must contain no arsenicnm In manutactunng the compound therefore before pouring the t.olntion of nitrate into water the liquid should be tested for arsenicura by oue of the hydro- gen te^ts, if that element be present the >!oluhonmust be o\aporated and only the deposited crj'stals be used in the preparation of the oxynitrafe. For on pouring an arsenical solution of nitrate of bis- muth into water, the arseniciua is not whoUy removed in the super- natant liquid, unless the osjnitrate be redissolved and reprecipitated several times, according to the amount of arsenicum present.
Such a product will probably contain more oxhydrate than oxynitrate.
Submtrate of Bismuth is sometimes administered in the form of a lozenge ( Troehied Biamttfhi, B. P.). It is nsed as a cosmetic under the name of Pearl-white {Blanc de Pe.rle).
Oxysalta of Biamuth.—It will be noticed that the formula for subnitrate of bismuth (BiNO,) does not accord with that of other nitrates, the characteristic elements of which are NOj. Analogy would seem to indicate, however, that the fourth atom of oxygen has different functions to the three in tlie NO, ; for on ponring solutitin of chluride of bismuth (BiClj) into water, o:xj"chloi'ide is produced
id, Google
(BiOCI) (a white powder useH as a cosmetic, also in enamels, anci in some varieties of senling-wax). The bromide (BiBr^) and iodide (Bilj) similarly yield oxybromide (liiOBr) and osyiodide (BiOI). The subnitrate (BiNOJ is, therefore, probably an anaiogons com- pound, an oxynitrate (BiONO,). The salphate (BiiSSOj also de- composes when placed in wat*r, giving what may be termed an oxjsulpbate {BijO^SOJ.
Suboarbonate or Oxycarbonate of Bismatlt.
Third Synthetical Eeaction. — To solution of nitrate of Msraiith add carbonate of ammonium; a white precipitate of hydrous oxycarbonate (aBijO^CO,, H^O) (Bismutki Oar- bonas, B. P.) falls. 2(Bi3NOJ + 3Am,C0, = fiAraNO, + Ei,0,CO, + 3C0^
According to the United States Pharmacopoeia the oxy- carbonate (Bismuthi Subcarbonas) is made by precipitating with carbonate of sodium a solution of the nitrate pre- pared from washed hydrate of bismuth.
This compound may be regarded as similar in constitution to the oxysalts just described. In Bi.jCO, one scarcely recogiiizes the char- acteristic elements of carbonates ; hat considering the preparation to be an oxycarbonate (BLjOjCO.) its relations to carbonates and oxides are evident. These snbsafts may all be viewed as normal bismuth salts iu which an atom of osygen replaces an equivalent pro- portion of other acidnloas atoms or radicals : —
Chloride Bi3Cl Oxychloride . BiOOl
Bromide Bi3Br Osybromide . BiOBr
Iodide Bi3I Oxjiodide . . BiOI
Nitrate BiSNO, Oxynitrate . BiONO,
Sulphate Bi,3S0, Oxysulphate . Bi.O^SOi
Carbonate (unknown) BijSCO, Oxycarbonate BijO^COj They may he viewed, in short, as salts in process of conversion to oxide; continue the substitution a little ftirther, and each yields oxide of bismuth (Bi,Oj). They have also been considered to be salts of a hypothetical univalent radical bismntliyl (BiO).
Citrate of fiismntk.
Fourth Synthetical Reaction. — To solution of nitrate of bismuth add citric acid and then solution of ammonia until the precipitate at first formed is redissolved, and the liquid after shaking has a slight ammoniacal odor. The product contains citrate of bismuth dissolved in solution of citrate and nitrate of ammonium. Made with definite quantities
id .y Google
208 RARER METALLIC RADICAF, S.
of ingredients and an amount of bismuth salt equivalent to till! tlirec grains of oxide (Bi^O,) in a fluidrschni, the solulion forms the Liquor Bismulhi et Avimonim Cilralis, B. P.
(b) lieaciions hauing Analytical Interest (Tests).
Fir&t Analytical Eeaciion. — Through solution of a bis- muth salt pass sulphuretted hydrogen ; a black precipitate of sulphide of bismuth (Bi,Sa) falls. Add ammonia (to neutralize acid) and then sulphydrate of ammonium ; the precipitate, unlike As.jS, and Sb^S,, is insoluble.
Second Analytical Reaction. — Concentrate almost any acid solution of a bismuth salt and pour into water; a ■white salt is precipitated.
This reaction is characteristic of biamutli salts ; it has already been amply esplained. The precipitate is distinguished from one formed
The reader is again advised io trace out tlic exact nature of each of the foregoing veactiuus, cliiofly Isy aid of e(|iiLxtions or diagrams.
QUESTIONS AND EXEECISK3.
337. Enumerate the 15 commoner metals.
328. Meotion the 11 rarer metals.
329. Name the som-ces and official compounds of lithium.
330. Give an equation explanatory of the formation of Citrate of Lithium.
331. What is the strength of Liquor Liihi<e Effervescens?
332. On what chemical hypothesis are lithium componuds admi- nistered to gouty patients ?
333. Describe the relation of lithium to other metals.
334. What is the chief test for lithium ?
335. Write a paragraph on strontium, its natural compounds, chemical relations, technical applications, and tests.
336. What are the formnlie and properties of oxalate of cerinm ? SSt. Name the commonest ore of manganese, and give an equation
descriptive of its reaction with hydrochloric acid.
338. Explain the formation of permanganate of potassium, employ- ing diagrams or equations.
339. In what manner do the manganates of potassium act as dis- infectants t
340. What are the chief tests for maugiiucso ?
id .y Google
QUESTIONS AN1> EXERCISES. 209
341. What are tlie chief uses of tlic oompouuds of cobalt ?
342. How are salts of cobalt analytically distinguished from those of nickel?
343. Mention on application of nickel in the arts.
344. What is the genera! color of nickel salts ?
345. Sta,te themethodof preparation of red chromate of potassinm. 346.. Give theformulfe of red and yellow chromates of potassium.
347. How ia red chromate of potassium obtained ?
348. Describe the action of sulphuretted hydrogen on acidified solutions of chi-omates.
349. 'What is the formula of chrome alum 1
350. Mention the chief testa for the chromic radical, and for chro-
351. How would yon detect iron, chromium, and aluminium in a solution ?
352. Define the terms tinstone, stream-tin, block-tin, grain-tin, tin-
353. Describe the poaition oli upied by tin in relation to other metals.
354. What is the difference between stannic acid and in eta-stannic acid?
355. State the Qppllc^tlons of tm in the arts.
356. Mention the chief tests for stannous and stannic salts.
357. Name the best antidote in cases of poisoning by tin solotions.
358. How is goid dust separated from the earthy matter with which it is nafarally associated?
359. How much pure gold is contained in English coin, and in jewellers' gold !
360. State the average thickness of gold leaf.
361 . What is the weight of a sovereign ?
362. Explain the term " fineness" as applied to gold.
363. What effect is produced on gold by hydrochloric, nitric, and nitrohydrocbloric aeida rMpectively 1
364. By what reagents is metallic gold precipitated from solutions of its salts ?
365. How is Purple of Cassius prepared ?
366. Whence is platinum 'obtained ?
367. Why are platinum oteneiis peculiarly adapted for use in che- mical laboratories !
368. How is perehloride of platinnm prepared !
369. Name the chief tests for platiuum.
370. What is "platinum black?"
371. Describe an experiment demonstrative of the large uinount of attraetion for gases possessed by metallic platinum.
372. How is "spongy platinum" produced?
373. By what process may the metal be recovered from i)latinuni residues ?
374. What is occlusion in chemistry ?
375. In what condition does cadmium occur in nature ?
376. By what process may Iodide of Cadmium fee prepared ? aiid in what form is it used in njedicine ?
]8*
id .y Google
210 KARER METALLIC RADICALS.
377. Mention the chief test for cadmium.
376. Distinguiiih sulphide of cadmium from other su!2)!u'lcs cf simi- lar color.
379. Howis cadmium separated from zinc ?
380. How does bismuth occur in natnre ?
381. What is the qnantiTalence of bismuth?
382. Write down equations descriptiTe of the action of Ditric acid on bismuth, and water on nitrate of Bismuth.
383. How may pure salts be prepared from bismuth containing
384. Give a diagram of the process for the so-called Carbonate of Bismuth.
385. Write formulie showing the accordance of the official Sub- nitrate and Carbonate ivith the other saJts of Bismuth, and with ordinary Nitrates and Carbonates.
386. How i& lAqimr Bismuthi ef Ammonim Citratis prepared?
387. What are the tests for Bismuth t
Practical Analyaie.
Bismuth is the last of the metals whose synthetical or analytical relatious are of general interest. The position of the rarer among the common metals, and the influence which either has on the other during the manipnlations of analysis, will now be considered. These objects will be best accomplished, and a more intimate acquaintance with all the metals be obtained, by analyzing, or studying the methods of analyzing, solutions containing one or more metallic salts.
Of the following Tablra, the first includes directions for the ana- lysis of an aqueous or only slightly acid solution containing but one salt of any of the metals hitherto considered. Here the color of the precipitate or precipitates afforded by a metal under given circum- stances must he relied on to a considerable extent in attempting the detection of the various elements.
The second Table is intended as a chart for the analysis of solu- tions containing salts of more than one of the common and rarer metals. It is einiply a compilation from the foregoing reactions — an extension of the selierao for the analysis of salts of the ordinary metals. Hence it often may be altered or varied in arrangement to suit the requirements of the analyst.
The third is a mere outline of the preceding Tables. It gives the position of the metals in relation to each otlicv, and will much aid the memory in recollecting that relatioi).
id .y Google
ANALYTICAL CHART FOR METALS.
|
J "i 1 |
m < 1 |
1 |
1 |
=111 ;i! |
1 s sis m |
|
|
1 |
S |
0 it |
"II sr^'^"! |
|||
|
■5 |
-!! |
1 |
g-S" |
|||
|
3 |
S 1 |
s a |
||||
|
21 |
||||||
|
1 |
1 |
s |
31 |
a |
||
|
q Msi |
||||||
|
ip |
% |
^^. i ,■1-^ tie- |
||||
|
1 |
1 |
|||||
|
1 1 ■p. 1 |
N i>^ o |
|||||
|
3 |
„S||!|'-:i ■ .gss |
|||||
|
a |
||||||
|
T- "Aa^^ ^^ — -^ ^ 1 |
||||||
|
M |
O WkSooBCMM =.= |
|||||
|
oi-S W |
||||||
|
^1 ^ ■ = "1 |
||||||
|
-^■w sJ'S'ao'? |
||||||
|
p |
g s |
Hoa,d, Google
METALLIC RADICALS,
OUTLINE OF THE PRECEDING
|
HOI |
H,8 |
AmH8 |
Am.GO;, |
Am^HAsO, |
|||
|
,.. »"£«=. |
Cd |
Zn |
1 |
Ba |
Mg |
K |
|
|
Pb |
(a.^4r. |
i |
Mil Co |
'1 |
Sr Ca |
Na Am |
|
|
M |
Fb (a liilUI Bi As |
1 |
Ni Al |
^ |
|||
|
salt) |
Fe |
1 |
L |
||||
|
Sb |
s |
t |
|||||
|
Sn salt) |
i |
Cv |
1 |
||||
|
An |
|||||||
|
Pt |
The laboratory studeDt should practise the examination of aqneons solutions of salts of the above metals until able to analyze with facility and accuracy.
General Memoranda.
These charts are constructed for the analysis of salts more or less
soluble in water. The student has still to learn how substances
insoluble in water are to he brought into a state of solution ; but, once dissolved, their aoalysis is effected by the same scheme as that just given. The second Table may therefore be regarded as fairly repre- senting the method by which metallic constituents of chemical sub- stances are separated from each other and recognized. The
id .y Google
ANALYTICAL MEMORANDA. 213
methods of isolation of the complernentary constituent of tlic salt (the reactions of non-metals and acidalous radicals} will form tho next object of practical study.
The group4eett adopted ia the Tables are, obviously, hydrochloric acid, Bulphurett«d hydrogen, snlphydrateofammoniam, carbonate of ammonium, and arseniate of ammonium. If a gronp-teat produces no precipitate, it is self-OTideat that there can be no member of the group present At first, therefore, add only a small quantity of g, group-test, 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 nnfrequently held in the liquid by excess of acid, alkali, or strong aqueous solution of some group reagent, thoughtlessly added. Indeed, experienced mani- pulators not unfrequently make preliminary trials with group-reagents on a few drops only of the liquid under examination ; if a precipitate is produced, it is added to the bulk of the original liquid and the addition of tbe group-reagent continued ; if a precipitate is not pro- duced, the few Stops are thrown away and the unnecessary addition of a group-reagent thus avoided aUogether, an advanta^ fully
making up for the extra trouble of making a preliminary trial.
While shunning excess, however, care must be taken to avoid defi- ciency; a substance only partially removed from solution through the addition of an insufficient amount of a reagent will appear where not expected, be consequently mistaken for something else, and cause much trouble; this will not occur if the appearance, odor, or reaction of the liquid on test-paper be duly observed. It is also a good plan, when a group-reagent has produced a precipitate and tbe latter has been fiitered out, to add a little more of the reagent to the clear filtrate; if more precipitate is produced, an insufficient amount of the group-test was introduced in the first instance ; but the error is corrected by simply refiitering ; if no precipitate occurs, the mind is satisfied and the way cleared for further operations.
Group-precipitates, or any precipitates still requiring esamina- tion, shonfd, as a rule, be well washed before farther testing; this is to remove the aqueous solution of other substances adhering to tbe precipitate (the mother-Hquor as it is termed), so that subseouent reactions may take place fairly between the reagent used and the
precipitate only. A precipitate 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, which usually eanses aggregation of the particles of a precipitate, and hence facilitates the passage of liquids.
Bivi^on of Work. — It is iuunaterial whether a solution be first divided into gronp-preoipitatt^ 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 Hj8 ppt.," and so on.
The colors and general appearance of the various sulphides and hydrates precipitated should be borne in mind, as the absence of other bodies, as well as the presence of those thrown down, is often at once thus indicated. For example, if a precipitate by sulphydrate
id .y Google
THE 11 E T A r, L I C RADICALS.
is white, neither cobalt, nickel, nor iron can be present, and only small quantities of manganese and chrominm. Application of conjirinatory tests must be freguent. Results of analyses should be recorded neatly in a memoranduni-
The various reactions which occur in an analysis hare already come before the reader in going through the tests for the individual metals or in other analytical operations, it is unnecessary, therefore, again to draw out 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-add precipitate may at first include some anti- mony and bismuth as oxychlorides, readily dissolved, however, by excess of acid. If either of these elements be present the wash- ings of the precipitate will probably be milky ; in that case odd a few drops of hydrochloric acid, which will clear the liquid and make way for the application of the teat for lead,
77ie sulphuretted-hydrogen precipitate may be white, in which case it is notling but sulphur; for, as already indicated, feiTic salts are reduced to ferrous, and chromates to the lower salts of chromium by sulphuretted hydrogen, sulphur being deposited :—
2re,CL + 2H-S = 4FeCl, -f 4H01 + S, ; 4HjCrO. + mS + 13H01 = 2Cr,Clo -+- 16HjO + ZS,.
The proportion of the sulphwretted-hydrogen precipitate dissolved hv sviphyarate of ammomum may include a trace of copper, sul- phide of copper being not altogether insoluble in sulphydrate of ammonium.— On adding hydrochloric aeid to the sulphydrate4)f- ammonium solution, a white precipitate of sulphur only may be pre- cipitated, the sulphydrate of ammonium nearly always containing free sulphur. — ^-Carbonate of ammonium does not readily dissolve small quantities of sulphide of arsenicnm out of much sulphide of antimony; and, on the other hand, carbonate of ammonium takes into solution a small quantity of sulphide of antimony if mnch sul- phide of arsenicum is present. The original solution should there- fore always be examined by the hydrogen testa for arsenicum and antimony if any doubt exists concerning the presence or absence of either. Tin remains in the hydrogen-bottle in the metallic state, deposited as a black powder on the zinc nsed in the experiment The contents of tlie bottle are turned out into a d^h, ebullition con- tinued until evolution of hydrogen ceases, and the zinc is taken np by the excess of sulphuric acid employed; any tin is then filtered out, washed, dissolved in a few drops of hydrochloric acid, and the liquid tested for tin by the usual reagents.
The portion of the siitphuretted-hydrogen precipitate not dis- solved by the sidphydraie of ammonium may leave a yellow semi- fuaed globnle of su^hcr on boiling with nitric acid. Ihis globule may be black, not only from presence of mercuric sulphide, but also
id .y Google
ANALYTICAL MEMORANDA. 315
from inclosed particles of other sulphides protected by the sulphur from the action of the acid. It may also coutain sulphate of lead, prodnced bv the action of nitric a«id on sulphide of lead. In cases of doubt the mass muafbe reraored from the liqnid, boiled with nitric acid till dissolved, the solution evaporated to remove excess of acid, and the residne examined ; but usually it may be disregarded. — — -In testing for lead by sulphuric acid the liquid should be diluted and set aside for some time.
Mercury may also be isolated by digesting the sulphuretted-hy- drogen precipitate in sulphydrate of sodium instead of sulpliydrate of ammonium. The sulphides of arsenicum, antimony, tin, and mercury are thus dissolved out. The mixture is then filtered, excess of hydrochloric acid added to it, and the precipitated sulphides col- lected on a filter, washed, and digested in sulphydrate of ammonium ; salphide of mercury remains insoluble, while the sulphides of arsen- icum, antimony, and tin are dissolved. By this method copper also appears in its right place only, sulphide of copper being quite insol- uble in sulphydrate of sodium. The other metals are then separated in the usual way.
The sulphydrate-of-amtnonmin precipitate mB.y,_ if the original solution was acid, contain Phosphates, Oxalates, Silicates, and Bo- rates of Barium, Calcium, and Magnesium. These will subsequently come out with the iron, and, being white, give the iron precipitate a iight^olored appearance ; their examination must be conducted sepa- rately, by a method described subsequently in connection with the treatment of substances insoluble in water. Precipitates contain- ing aluminium, iron, and chromium often carry down some manga- nese, which afterwards comes out with the iron. This manganese may be detected by washing the ferric hydrate to remove all trace of chlorides, boiling with nitric acid, adding pnce-colored oxide of lead, and setting the vessel aside ; permanganic aeid is formed, recognized in the clear liquid by its purjjle tint.-— Sulphide of nickel la not easily removed by filtration {vide p. 191) until most of the e\i,es3 of sulphydrate of ammonium has been dissipated by prolonged ebulli-
Tke carhonate-of-ammomum precipitate may not contain the whole of the barium, strontium, and calcium in the mixture, unless it; for the carbonates of those metals i
soluble in water charged with carbonic acid. If, therefore, the liquid is not distinctly ammoniacal, solution of ammonia should be added.
Neither carbonate nor hydrate of ammonium wholly precipitates
magnesian salts; and as a partial precipitation is nndesirable a sol- vent, in the form of an alkaline salt (chloride of ammonium), if not already in the Jiquid, should be added.
Lithium. — The search for lithium may usually be omitted. Should a precipitate, supposed to be due to lithium, be obtained, it must be tested in a flame (= scarlet tint), as a little maguesium not unfrequently shows itself under similar circumstances.
Syeetral Analysis. — If present only in minute proportions, the lithium may also remain with the alkalies; it can tnen only be de- tected by physical analysis (by a prism) of the light emitted from a
id .y Google
216 THE METALLIC RADICALS.
tinged flame — by. in short, an iiistrmiient termed a spectroscope. Such a method of examination is called spectra] analysis, a subject of much intereet and of no great difficulty, but scarcely within the range of Pharmaceutical Cnemiatry; it will be briefly desci-ibed hi connection with the methods of analyzing solid substauces.
QUESTIONS ANB EXERCISES.
388. Describe a ([eneral method of analysis by which the metal of a single salt in a solutloD could be quickly detected.
389. Give illustrations of black, white, light pink, yellow, and orange sulphides.
390. Mention the group-testa generally employed iu analysis.
391. Under what circumstaaees may a hydrochloric precipitate contain antimony or bismuth ?
392. If a aolphnretted-hydrogen precipitate is white, what sab. stances are indicated ?
393. Give processes for the qualitative analysis of liquids contain- iiig the following substances: —
a. Arsenicum and Cadmium. 6. Bismuth and Antimony.
c. Ferrous and Ferric salts.
d. Aluminium, Iron, and Chromium.
e. Arsenicum, Antimony, and Tin. /. Lead and Strontium,
g. Iron aud Phosphate of Calcium. h. Mercury, Manganese, and Magnesium. i. Zinc, Manganese, Nickel, and Cobalt. j. Barium, Strontium, and Calcium.
id .y Google
THE ACIDULOUS KADICALS.
Introduction. — The twenty-9L\ radicaie which haye up to this ])oitit maiDiy occnpied attention are (admitting ammonium, NII^) me1«ls; and they have beea almost exclusivelj studied not in the free state, but in the condition in which they exist in salts. More- over these metals have been treated aa if they formed the more important constituent, the stronger half, the foundation or base, of suits. Attention has been coutinnonsly directed to the metallic or baayloiM side of salts. There is, indeed, still one more basjious radical worthy of a passing notice, though it usually is supposed to play only a subordinate part in reactions — Hydrogen. Unlike the saite of most metals, those of hydrogen are never, in medicine or the arts generally, professedly used for the sake of their hydrogen, but always for the other half of the salt, the actdulotts side. And it is not for their basylous radical that these hydrogen salts are now com- mended to notice,* but in order to study, under the most favorable circumstances, those acidulous groupings which have continually presented themselves in operations on s^ts, but which were for the time of secondary importance. They may now be treated as the primary object of attention ; and there is no better way of doing so than in operating on their compounds with hydrogen, the relatively inferior medicinal importance of which element, as compared with
Sotassium, iron, and other basylous radicals, will serve to give the esired prominence to the aciduloua radieaia in question. Common Adda. — These salts of hydrogen are the ordinary, sharp, sout bodies termed acids (from the Latin root aaies, an edge). The following Table includes liie forrauke and names of the most import- ant; others will be noticed subsequently. A few of those mentioned aro unstable or somewhat rare; iu such cases a common metallic salt containing the acidulous radical may be used for reactions.
* It must not be forgotten that the commonest salt of any radical whatsoever is a salt of hydrogen, the oxide of hydrogen (HjO), or liydrate of hydrogen (HHO), tealer. In the reactions already per- formed, the value of this compound has been constantly recognized, both for its hydrogen and for its oxygen, but most of all as the vehicle or medium by which nearly all other atoms are enabled to come into that contact with each other without which their existence wonid be almost useless ; for some atoms are tike some animals, out of water they are as inactive as fishes. It is true that both fishes and salts have usually to be removed from water to be ntiliied by man ; but before they cao be assimilated, either as food or as medicine, they roust again seek the agency of water — become dissolved. 19
id .y Google
|
rHE ACIDULOUS EADICALS. |
|
|
HCl |
hj-droohlorio acid. |
|
HBr |
hj-drobromic acid. |
|
HI |
hydriodic acid. |
|
HON (HCy) |
hydrocyanic acid. |
|
HNO, |
nitric acid. |
|
HOlO, |
chloric acid. |
|
H0,H,O, |
acetic acid.* |
|
H,8 |
hydrosulpharic acid t |
|
H,SO, |
|
|
H,so: |
sulphuric acid, carbonic acid. |
|
H,OOJ |
|
|
HC,0, |
oxalic acid. |
|
HjO.H.O, |
tartaric acid. |
|
H,C,H,0, |
citric acid. |
|
H,PO, |
boracic acid. |
A prominent point of difference will at once be noticed between the basylous radicals met with up to the present time and the acidu- lous groupings included in the above tabular list. The former are nearly all eleuients, ammonium only being a compound ; the latter are mostly compounds, chlorine, bromine, iodine, and sulphur being the only elemeota. This difference will not, however, be so appa- rent when the chemistry of alcohols, ethers, and such bodies has been mastered, for they are all salts of compound basylous radicals.
Rarer Acids. — The above acids contain the only acidulous group- iuga that commonly present themselves in analysis, or in pharma^ ceutical operations. There are, however, several other acids (such as hypochKirous, nitrous, hypophosphorous, valerianic, benzoic, gallic, tannic, uric, hyposulphnrous, hydroferrocyanic, hydroferridcyanic, and lactic) with which it is desirable to be more or less familiar; reactions concerning these will therefore be described. Arsenioua, arsenic, stannic, manganic, and chromic acids have already been treated of in connection with the metals they contain ; in practical analysis they always become sufficiently altered to come out among the metals.
Quantivalence. — A glance at the foregoing Table is sufficient to show the quantivalence of the acidulous radicals. The first seven
* The hydrogen on the acidulous side must jiot be eonfoundcd with the basylous hydrogen in all these hydrogen salts or aeids ; the two perform entirely different functions. Hydrogen in the acidulous portion is hke the hydrogen in the basylous radical ammouiam, it has combined with other atoms, to form a group which plays mora or less the part of an elementary radical, and to which a single sym- bol is not uufrequently applied (Am ; Cy, A, O, T, C, &c.). Cobalt, chromium, iron, platinum, &c. resemble hydrogen in this respect in often uniting with other atoms to form definite acidulous radicals, in which the USU9.1 basylous character of the metals has for the time disappeared. In hydrides (p. 92) hydrogen itself is an acidulous
t Synonyms: gulpljydrio acid and sulphuretted hydrogen.
id .y Google
CHLORIDES. 219
are clearly iiuivalent then follow six bivalent, leaving three tri- valent.
These all combine with pqun alent amounts of basjlous radicals to form various salts ; hence thej may be termed moiiobasylous, di- baeylous, and tribasyluus radit-als The acids themselves were for- merly spoken of as monobasic dibasic and tribasic respectively, or monobaaic and polybasic in reference to the amount of base {hy- drates or osides) they could decompose bnt the terms are no longer definite, and hence but little nsed in mineral chemistry.
Analysts. — The practical study of the acidulous side of salts will occupy far less time than the basylous. Salts will then be briefly examined as a whole.
One viord of caiUion. It is only for convenience in the division of chemistry for systematic study that salts may be considered to contain basylous and acidulous radicals, or separate sides, so to speak ; for we possess no absoln(« knowledge of the internal arrangement of the atoms ( admitting that there are such things) in the molecule of a salt. We only know that certain groups of atoms may be trans- ferred from compound to compound in mass (that is, without apparent decomposition) ; hence the assumption that these groups are radicals. A salt is probably, however, a whole, having no such sides as those mentioned.
QUESTIONS AND EXERCISES.
394 Mention the basylous radical of acids. 393. Give illustrations of univalent, bivalent, and trivalent acidu- lous radicals, and monobasylous, dibasylous, and tribasjlous sails.
396. What is the difference between an elementary and a com- pound acidulous radical ?
397. Name the grounds on which salts may be assumed to contain basylous and acidulous radicals.
HYDROCHLORIC ACID AND OTHER CHLORIDES.
Formula of hydrochloric acid HCI. Molecular weight* 36.5.
The acidulous radical of hydrochloric acid and of other chlorides is the element chlorine (01). It occurs in nature chiefly as chloride of sodium (NaOl), either solid, under the name of rock-salt, mines of which are not unfrequently met with, or in solution in the water of al! seas. Common table-salt is more or less pure chloride of so- dium in minute crystals. Chlorine, like hydrogen, is univalent (01'); its atomic weight is 33.5. Its molecule is symbolized thus, Olj, chloride of chlorine.
* The weight of a moleoule is the sum of the weighta ot Its atoms.
id .y Google
220 SALTS or ACIDULOUS RAmOALS.
Ee ACTIONS.
Hydrochloric Acid. First Synthetical Eeaction. — To a few fragments of chlo- ride of eodiiim in a teat-tube or small flask add about an equal weight of sulphuric acid; colorless and invisible gaseous hydrochloric acid is evolved, a sulphate of sodium remaining. Adapt to the mouth of the vessel, by a per- forated cork, a piece of glass tubing bent to a right angle, heat the mixture, and convey tbe gas into a small bottle containing a little water; solution of hydrochloric acid results.
NaCl + H,SO. = HCl -+ NaHSO,
' B'^drocltlortG Acid. — Tlie product of this operation is the nearly colorless and very bout liquor commonly termed hydrochloric acid. Wlien of certain given, strengtlis [estimated by yolnmetric analysis) it forms Acidtim ^drochlortcvMi, B. P. and U. 8. P., and AadiMii Hydrochloricwm. Bihitum, B. P. (and U. S. P., specific gr. 1.038). The former has a specific gravity of 1.16 (1.1578), and contains 31.8 per cent, of real acid, the latter specific gravity 1.052, with 10.58 per ceat. of real acid, and is made by diluting 8 fluid parts of the strong add with water until the mixture measures 26f flmd parts The above process is that of the Pliarmacopceiaa— laiger veesela bemg employed, and the gas being freed from any trace of sulphuric acid by washing. Other chlorides yield hydrochlone acid when heated with sulphnric acid ; bnt chloride of sodium is always used because cheap and common. The acid is a by-product m the manufacture of carbonate of sodinm from common salt, a procesH in which the chlo- ride of sodium ia first converted into sulphate, hydi-ochlonc acid bemg liberated.
The official (B. P.) process is as fohows :— " Take of chloride of sodinra, dried, 48 ounces, sulphuric acid 44 fiuidounces, water 36 fluidonnces, distilled water 50 fluidounces ; pour the Bnlphuric acid slowly info thirty-two ounces of the water, and, when the mixture has cooled, add it to the chloride of sodium pre- viously introduced into a flask having the capacity of at least one gallon. Connect the flask by corks and a bent glass tube with a Qiree-necked wash-bottle, foruished with a safety tube, and contain- ing the remaining four ounces of the water ; then, applying heat to the flask, conduct the disengaged gas through the wash-bottle into a second bottle containing the distilled water, by means of a bent tube dipping abont half on inch below the surface, and let the process be continued until the product measures sixty-six ounces, or the liquid has acquired a specific gravity of 1.16. The bottle containing the distilled water must be kept cool during the whole operation."
id .y Google
OHLOaiBEs. 221
Invisible gaseous hj/drockloric acid forma visible grayish-white fumes on coming into contact with air. This is due to combination with the moisture of the air. The intense greediness of hydroehloria gas and water for each other is strikingly demoustrated oa opening a tesl-tube fall of the gas under water ; the latter, rushes into and in- stantly fills the tube. If the water is tinged with blue litmus, tho acid character of the gas is prettily shown at the same time. The test-tube, which shonla be perfectly dry, may be filled from the de- livery-tube direct; for the gaa is somewhat heavier than, and there- fore readily displaces, air. The month may be closed by the thumb of the operator.
Nbie. — The process, as described in the British Pharraacopceia, includes the nse of as much snlpharic acid as ia theoretically neces- sary for the production of acid sulphate of sodium (NaHSOj) which remains in me generating vessel. A hot solution of this residue carefully neutralized by carbonate of sodium, filtered and set aside, yields normal sulphate (Sodce Sulphas, B. P. and U. S, FX in the form of transparent oblique efflorescent prisms (Na^SOj, lOH^O).
SNaHSO, -f Na^CO, = 2Na,S0, + H,0 -f CO,
Chlorine.
Second Synthetical Seaction. — To some drops of hydro- chloi'ic acid (that is, the common aqueous solution of the gas) add a few grains of black oxide of manganese, and warm the mixture ; chlorine, the acidulous radical of all chlorides, is evolved, and may toe recognized by its peculiar odor, or irritating effect on the nose and air-passages.
4HC1 + MnO, = CI, -f 2H^0 + MnOl,
Chlorine-vyater. — This is the process of the Pharmacopteias for the
S reduction of chlorine-water (Liquor Ghiori, B. P., Aqua Gldorinii, '. S. P.), the gas being first washed and then passed into water. Six fiuidounces of hydrochloric acid diluted with two ounces of water, and the gas passed through a wash-bottle containing about two ounces of water, yield enough chlorine to produce about a pint and a half of chlorine wat«r. On the small scale, less than half the acid is utilized through incomplete decomposition and incomplete absorption of the chlorine gas. Chlorine slowly decomposes water with production of hydrochloric acid ; it is best preserved in a green-glass welt-stoppered bottle in a cool and dark place.
jVbfe. — To obtain the chlorine ftom other chlorides, sulphuric acid, as well as black oxide of manganese, must be added. Hydrochloric acid is first formed. The action described ia the above eqnation then goes on, escept that half instead of the whole of the oxygen of the black oxide is available for the removal of the hydrogen from the chlorine of the hydrochloric acid, the other half being taken up by 19*
id .y Google
222 SALTS OF ACIDULOUS RADIO
the hydrogen of the sulpliuric acid. Thus, supposing c
to he tlie chloride used, the following equatioas may represent the
■sapposed steps of tlie process ; —
2Na01 + HjSO, = Na,SO, + 2HC1, MnO. + HjSO, = MnSO. + H^O + 0; then the 2HCI +0 = H,0 + CI, ;
or the whole may be included in one equation -. 2NaCl + MnOj + 2H28O, = Na^SO, + MnSOj + 211^0 + 01^ This reaction may have occasional analytical interest, a very small quantity of combined chlorine being recognized by its means. But yje following reaction is nearly always applicable for the detection of this element, and leaves nothing to be desired in point of delicacy.
Analytical Reaction ( Test).
To a drop of hydrochloric acid, or to a dilute solution of any other chloride, -add solution of nitrate of silver; a white curdy precipitate falls. Pour off most of the super- natant liquid, add nitric acid, and boil; the precipitate does not dissolve. Pour off tbe acid, and add ammonia; the precipitate quickly dissolves. Neutralize the solution by an acid, chloride of silver is once more precipitated.
The formation of this white precipitate, iU appearance, insolubility in boiling nitric acid, solubility in ammonia, and reprecipitation by an acid, form abundant evidence of the presence of chlorine. Ite occurrence as a chloride of a metal is determined by testing for the metal with the appropriate reagents ; its occurrence as hydrochloric acid is considered to be indicated by the odor, if strong, and the sour taste, if weak, of the liquid, and the action of the liquid on the litmus paper, which, like other aoida, it reddens. If hydrochloric acid be present in excessive quantity it will, in addition to the above reac- tions, give rise to strong effervescence on the addition of a, carbonate, a chloride being formed. The chlorine in insoluble chlorides, such as calomel, " white precipitate," &e., may be detected by boiling with cai»tic potash, filtering, acidulating the filtrate by nitric acid, and then adding the nitrate of sOver.
Anlidotes.— Id cases of poisoning by strong hydrochloric acid, solution of carbonate of sodium (common washing-soda) or a mixture of magnesia and water may be administered as an antidote.
QUESTIONS AND EXEECISKS.
398. Aspecimen of oEBcial Hydrochloric Acid contains 31.8 per cent, by weight of gas, and its specific gravity is 1.16 ; work out a sum show- ing what volume of it will be required, fieoretically, to mix with black oxide of manganese for tlio production of one gallon of chlo-
id.y Google
rine-water, one fluidotmee of which contains 2.66 grains of chlorine. Ans. 5^ fluidonnceB, nearly,
399. Why does hydrochloric acid gas give visible fumes on coming into contact with air ?
400. How much chloride of sodium wOl be required to furnish one pound of chlorine ?
401. Give the analytical reactions of chlorides.
402. What antidotes may be administered in cases of poisoning by hydrochloric acid ?
HYDROBaOMIC ACID AND OTHER BROMIDES.
Formula of Hydrobromic Acid HBr. Molecular weight 81.
Bromine. Sowroe, Preparation, and Properties.— '^he acidulous radical of hydrobromic aeid and other bvomides is the element bromine, Br (Bromum, B. P., Bromdnium, tJ, S, P.). It occurs in nature chiefly as bromide of magnesium in sea^water and certain saline springs. It may be liberated from its compounds by the pro- cess for chlorine from chlorides— that is, by heating with blaek oxide of manganese and sulphuric acid. It is a dark-red volatile liquid, emitting an odor more irritating, if possible, than chlorine — of specific gravity 2.966, boiling-point 117°.
Quafdivalence. — The atom of bromine, like that of chlorine, is uni- Vftleut (Br'} ; its atomic weight is 80. Free bromine has the molecular formula Br,, bromide of bromine.
Hydrobromic Acid.—Tha bromide of hydrogen, hydrobromic acid, is made by decomposing bromide of phosphorus by water— PBr, -f- 4H30=5HBr+H3pO^.
Bromide of Potassium (KBr) is occasionally employed in phar- macy, and is the salt, therefore, which may be used in studying the reactions of this acidulous radical. The official method of making the salt has been alluded to under the salts of potassium (page 52).
Other bromides are seldom used ; they may be prepared in the same way as, and closely resemble, the corresponding chlorides or iodides.
Bromide of Ammonium (AmBr) {Aminonii Bromidum, B. P.) aade by t ' " ' ' ' " " ""
' saturating hydrobromic acid With i H:Sr + NB:4HO'=NH,Br + H50. It forms colorless crystals which become slightly yellow on exposure to air, is readily soluble in water, less so in spirit, and, when heated, sublimes.
Solution of Bromine, B. P., 10 minims in 5 ounces, is an aqueous solution, bromine being slightly soluble in water.
Hypobromites, Bromatea, Perbromates, analogous to hypochlo- rites, chlorates, and perchlorates, are producible.
Analytical Reactions ( Tests). First Analytical Reaction. — To a few drops of solution of a bromide (KBr, or NH^Br) add solution of nitrate of
id .y Google
224 SALTS OP ACIDULOUS KADIOALS.
silver ; a yeUo wish-white precipitate of bromide of silver (AgBr) falls. Treat the precipitate successively with nitvic acid and ammoaia, as described for the chloride of silver ; it is only sparingly dissolved by the ammonia.
Second Analytical Beaciion. — To solution of a bromide add a drop or two of chlorine-water, or a bubble or two of chlorine gas ; then add a few drops of chloroform or ether, shake the mixture, and set the test-tubo aside ; the chlo- rine, from the greater strength of its affinities, liberates the bromine, which is dissolved by the chloroform or ether, the solution falling to the bottom of the tube in the case of the heavy chloroform, or rising to the top in the case of the light ether. Either solution has a distinct yellow, or red dish -yellow or red color, according to the amount of bromine present.
jVofes. — This reaction serves for the isolation of bromino when mixed with manj other substances. Excess of chlorine must he avoided, as colorless chloride of bromine is then formed. Iodides give a somewhat similar result; the absence of iodine must therefore be insured by a process given in the next section. The above solu- tion in chloroform or ether may be removed from the tube bj draw- ing up into a pipeiCe {small pipe, a narrow glass tube, usually having a bulb or expanded portion in the centre) the bromine fixed by the addition of a drop of- solution of potash or soda, the chloroform or etber evaporated off, and the residue tested as described in tlie next reaction.
The above operation is frequently employed for synthetical pur- poses.
Third Analytical Reaction. — Liberate bromine from a bromide by the cautious addition of clilorine or chlorine- water, then add a few drops of cold decoction of starch ; a yellow combination of bromine and starch, commonly termed " bromide of starch," is formed.
Decoction of starch is made by rubbing down two or three grains of starch with some drops of cold water, then adding much more water and boiling the mixture.
The above reaction may he varied by liberating the bro- mine by a little black oxide of manganese and a drop of sulphuric acid, the upper part of the inside of the test-tube being smeared over with some thick decoction of starch or thin starch-paste.
id .y Google
HYDRIODIC ACID AND OTHER IODIDES,
Formula of Hydriodio Acid HI. Molecular weight 128.
Source.— The acidulous radical of hydriodic acid and other iodides is the element iodine (I). It occurs in nature chiefly as io^de of sodium and of magnesium in sea-water. Seaweeds, sponges, and other marine organisms, which derive much of their nourishment from sea- water, store up iodides in fleir tissues, and it is from the ashes of these that supplies of iodine (lodum, B.F., lodmimn, U.S. P.) aro obtained.
Pfoeess. — Iodine is liberated from iodides as bromine from bro- mides, or chlorine from chlorides — namely, by the action of black oxide of manganese and sulphuric acid.
Properties. — Iodine is a crystalline purplish-black substance ; its vapor, readily seen on heating a fragment in a test-tube, is dark violet Its vapors are irritating to the lungs; but a trace may be inhaled with safety ( Vwpor lodt, B. P.). It melts at 239", boils at about 3920, and is entirely volatilized, the first portions containing any cyanide of iodine that may be present. The latter body occurs in slender colorless prisms, emitting: a pungent odor.
Qwmtivaleiice. The atom of iodine, like those of bromine and chlorine, is univalent* {I'); its atomic weight is 127, its molecular fonnula Ij.
The Iodide o/ Bydrogen, or Hydriodic Aoid, is a heavy, color- less gas. Its solution in ■via.i^T^AciiMm.Hydriodieum Dilutum, U. S. P.) IS made bj passing sulphuretted hydrogen through water in which iodine is suspended, 2H,a -f 21, = 8, + 4HI. Iodide of potassium (KI) is largely used in medicine, and hence is the most convonieat iodide on whidi to esperiment in studying the reactions of this acidulous radical Sobd iodine itself might be taken for the
iiurpose ; but its use and action m that state have already been al- uded to in describing the iodides of potassium, cadmium, and mer- cury t its analytical reactions in the combined condition are those which may now occupy attention
Solvtiort of /odjJie —Iodine is slightly soluble in water (iodine- water), and readily soluble in an aqueous solution of iodide of potas- sium. Twenty grains of lodme and 30 of iodide of potassium, dis- solved in 1 ounce of distilled water, form Liquor lodi, B. P. ; Liquor lodinii Oompoaitus, IF. 3. P., is of the same character and about the same strengtli ; 32 grains of iodine and 32 of iodide of potassium, rubbed with 1 fluidrachm of proof spirit, and 2 ounces of lard gradually mixed in, form Vhguentwn lodi, B. P. Unguentvm lodinii Compositwm, U. S. P., aud Unguentum lodinii, V. 8. P., are similar preparations. It ig 'more soluble in spirit {Tinctwra
'"'There is a componnrl of iodine having the formula ICIj. Iodine would therefore seem to be a trivalent element (I'") ; and bromine and fluorine, from their close chemical analofjy with iodine, would neoaasarily be regarded as trivalent also. From this aspect the posi- tion of chlorine would be anomalous.
id, Google
226 SALTS OF ACIDULOUS RADICALS.
lodinii, U. S. P.), or in a spirituous solufion of iodide of pota^ium ( Tinctwra lodi, B. P., Tinctivra lodimi Composita, U. S. P.). It combines with sulphur, forming an ungtahle grayish-black solid iodide (8j Ij), having a radiated cryatalline structure {Sviphwfis lodvm, B. P. aad U. S. P., and Vhguetitim, Stdphwis lodidi). "If 100 grains be thoroughly boiled with water the iodine will pass off ia vapor, and about 20 grains of snlpliur remain." — Brit. JPharm.
Analytical Heactions ( Tests).
First Analytical Reaction. — To a few drops of an aque- ous solution of an iodide (e. g. KI) add solution of nitrate of silver ; a yellowish- white precipitate of iodide of silver (Agl) falls. Pour away the supernatant liquid and treat the precipitate with nitric acid, it is not dissolved ; add ammonia, it is only sparingly dissolved.
This reaction is useful in separating iodine from moat other acidu- lous radicals, but does not distingnish iodine from bromine.
Ammonia, it will be remembered, dissolves chloride of silver readily; hence the presence of chloride of potassium in bromide or iodide may be detected by dissolving in water, adding excess of nitrate of silver, collecting the precipitate, washing, digesting in ammonia, filtering and adding ezcMS of nitric acid to Wie filtrate ; a white cnidy precipitate indicates a chloride (of potassium}.
Second Analytical Reaction. — Liberate iodine from an iodide by the cautious addition of chlorine, then add cold decoction of starch ; a deep-blue combination of iodine and starch, commonly termed "iodide of starch," is formed.
Starch is highly sensitive to the action of iodine ; this reaction is consequently very delicate and characteristic. Excess of chlorine must be avoided, or colorless chloride of iodine will be produced. Nitrous acid, or a nitrite acidulated with sulphuric acid, may be used instead of chlorine. The reaction ia not observed in hot liquids.
In testing bromine for iodine the bromine must be nearly all re- moved by solution of sulphurous acid before the decoction of starch is added.
Ozone (Oa).— Papers soaked in mncilage of starch containing iodide of potassium, form a test for free chlorine and nitrous acid, and are also employed by meteorologists to detect an allotropic and energetic form of oxygen termed by SchOnbein ozone (from Sfu, o ^ fo smell). This substance liberates iodine from iodide of potassii (with formation of iodide of starch), and is supposed fo occur n mally in the atmosphere, the salubrity or insalubrity of which is said to be dependent to some extent on the presence or absence of t " The possible occurrence of nitrous or ehlorinoid gases in thi however, renders the test untrustworthy. Houzean proposes to test for ozone by exposing litmus paper of a neutral tint soaked in a dilute solution of iodide of potassium ; the potash set free by action of the
id .y Google
IODIDES. 221
ozone turns the paper blue. The anme paper witliout iodide would indicate tte extent to which the effect might be due to ammonia va- por, Ozoae, or rather ozoniaed air, ia prodaced artificially in large quantitiea ou pacing air through a bos (Beane's Ozone-generator) highly charged with electricity. Small quantities may be obtained by exposittg in a loosely closed bottle a stick of phosphorus partially covered h^ water. It is a powerful bleaching, disinfecting, and general oxidiaing agent ; insoluble in water, soluble in oils of turpen- tine, cinnamon, and some other liquids. From experiments that have been made by Soret on the specific gravity of ozone, its molecular formula would seeni to he Oj, that of ordinary osygca being Oj. Its smell is pecoliar.
Third Analytical Reaction. — To a neutral affueous solu- tion of an iodide add a solution coiitaiuiiig one part of sulphate of copper to two parts of green sulphate of iron ; . a dirty-white precipitate of cuprous iodide (CUjI,) falls. 2KI -f 2CuS0. + 3Fe80, = CuJ, + K.80, + Pe,3S0,
Separation of Ghlorides, Broimdes, and /od/de*.— Chlorides and bromides are not affected in this way; the reaction is useful, there- fore, in removing iodine from a solution in which chlorides and bromides have to be sought The total removal of iodine bj this process is insured by supplementing the addition of the cnpric and ferrous sulphate by a few drops of ammonia, any acid which might be keeping cuprous iodide in solution being thereby neutralized, ferric or ferrous hydrate, precipitated at the same time, not affecting the reaction. Chloride of the rare metal palladium performs a similar useful office in removiog iodine, but not bromine or chlorine, from solutions. Chlorides may he separated from bromides by taking advantage of the ready solubility of chloride of silver, and almost complete insolubility of bromide of silver in ammonia.
Fourth Analytical Reaction. — Iodides have been shown to be useful in testing for mercnric salts (see the Mercury reactions, p. 155) ; a mercuric salt (corrosive sublimate, for example) may therefore be used in testing for iodides, a scarlet precipitate of mercuric iodide (Hglj) being pro- duced.
This reaction may be employed where large quantitiea of an iodide are present; hnt its usefulness in analysis is much impaired by the fact that the precipitate is soluble in excess of the dissolved iodide, or in excess of the mercuric reagent. I1« color and insolubility in water distinguish it from mercuric chloride, bromide, and cyanide, which are white soluble salts.
Fifth Analytical Reaction. — Iodides have also (see the Lead reactions, p. 172) been shown to be useful in testing for lead salts ; similarly a lead salt (acetate, for example) may be used in testing for iodides, a yellow precipitate of
id .y Google
228 SALTS OP ACIDULOUS RAtilCALS.
iodide of lead (FMa), soluble in hot water and crystallizing in yellow scales on cooling, being produced.
Chloride, bromide, and cyanide of lead are white ; hence the above reaction may occasionally be UEeful in distinguishing iodine from the allied radicals. But iodide of lead is slightly soluble in cold water ; hence small qnantities of iodine cannot be detected by this reaction. (For lodaies see p. 244.)
QUESTIONS AND EXEBOTSES.
403. State the method by which Bromine is obtained from its natural compounds.
404. Mention the properties of bromine.
405. How may the Bromides of Potassium and Ammonium be made?
406. By what reagents may bromides be distinguished from chlorides !
407. "Whence is iodine obtained?
408. By what process is iodine isolated?
409. State the properties of iodine.
410. What is the nature of Iodide of Sulphur ?
411. G-ive the analytical reactions of iodides.
412. Which three substances may be detected by a mixture of iodide of potassium and mncilage of starch ?
413. Describe a method by which iodides may be removed from a solution containing chlorides and bromides.
HYDROCYAKIC ACID AND OTHER CYANIDES.
Formula of Hydrocyanic Acid HNC or HCy. Molecular weight 27.
Hisiory of Gyano^en. — The acidulous radical of hydrocyanic acid and other cyanides is a compound body, cyanogen (Cy). It is so named from xi^nn, kvanoa, blue, and ytiivaui, gennao, I generate, in allusion to its prominent chemical character of forming, with iron, the different varieties of Prussian blue. It was from Prussian blue that Scheele, in 1782, first obtained what we now, from our know le^e of its compoaition, term hydrocyanic acid, but which he called Prossic acid. Cyanogen was isolated by Gay-Lussac in 1814, and waa the first compound radical distinctly proved to exist.
Sources. — Cyanogen does not occur in nature, and is only formed froiD its elements under certain circumstances. It is found in small
anantitjes among the gases of iron-fnrnaces, and is produced to a ight extent in distilling coals for gas. In the form or ferrocyanide of potassium it is obtained abundantly by heating animal refuse
id .y Google
CYANIDES. S39
containing nitrogen, encli as the scrapings of horns, hoofs, and hides (5 parts) with carbonat* of potassium (2 parts) and waste iron (filings, iBc.) in a covered iron pot The residual mass is boiled with water, the mixture filtered, and the filtrate evaporated and set aside for crystals to form. The cyanogen, produced from the carbon and nitrogen of the animai matter, unites with the potassium and then with iron to form what is known as the yellow prussiate of potash iPotansm Prussias Ftava, B. P.), or ferrocyanide of potassium (K'jFe"0/,), (Potassii Ferrocyamdvm, U. S. P.), a compound occurring in four-sided tabular yellow crystalB. It contains the elements of cyanogen, yet it is not a cyanide, for it is not poisonoiia, and is otherwise difierent from cyanides ; it will be further noticed subsequently. Prom this salt all cyanides are directly or indirectly prepared.
Cyanide of pofassivm (ECy), [Potassii Gyanidum, U. S. P.), which is the most common, is procured by fusing ferrocyanide of po- tassiam in a crucible ; carbonic acid gas (CO,) is evolved, iron (Fe) ia set free, and cyanate of potassium (KCyO), a body that will be subsequently noticed, is formed. at the same time ; —
2K,FeCya + 2K,00, = lOKCy + 2KCyO + Fe, + 200j.
Double cyanides exist, such as the cyanide of sodium and silver (NaOj',AgUv), formed in the process (subsequently describedj of (juantitatively determining the amount of hydrocyanic acid m a liquid by a standard solution of nitrate of silver; these compounds have, more or less, the properties of their constituents. Bnt other cyanogen compounds, not double cyanides, occur in which the cyano- gen is so intimately united with a metal as to form a distinct radical : such are ferrocyanides and ferridcyanides — salts which will be noticed in due course.
Cyanogen, like chlorine, bromine, and iodine, is univalent (Cy'), It may be isolated by simply heating mercuric cyanide (HgOyjj or cyanide of silver ( AgOy). It is a colorless gas, bnrning, when igmted, with a beautiful peach-blosaom-colored flame.
Mercurip cyanide is produced in crystals on dissolving 1 part of ferrocyanide of poti^inmin 15 parts of boiling water, adding 2 parts of mercuric sulfate, keeping the whole hot for ten or fifteen minutes, and then filtering and setting aside to cool. In addition to mercuric cyanide (HgCyJ, mercury (Hg), ferric sulphate (Fe,380J and sul- pliate of potassium (K^O,) , are formed. Any excess of ferro^anide also gives Prnssiaai blue by reaction with ferric sulphate. It {Hy- dratgyri Cyanidum,, U. S. P.) may also be made by dissolving red oxide of mercury in dilated hydrocyanic acid. A small flame of cyanogen may be obtained on heating a few crystals of mercuric cyanide in a short piece of glass tubing closed at one end, and apply- ing a light to the other end d& soon as evolution of gas commences.
id .y Google
DUL0U8 RADICALS.
Diluted Hydrocyanic Acid.
Syniheiieal Beaction. — Dissolve 2 or 3 grains of ferrocya- nide of potassium in 5 or 6 times its weight of water in a test-tube, add a few drops of sulphuric acid and boil tlie mixture, conveying the evolved gas by a bent glass tube (adapted to tlie test-tnbe by a cork) into another test-tube containing a little water ; the product is a dilute solution of hydrocyanic acid. Made by this process in large quan- tities of a certain definite strength (2 per cent.), this solu- tion is the Acidum Hydrocyanicum. Dilutum, B, P., and F. S. P. "A colorless liquid of a peculiar odor. Specific gravity 0.991."
SK^FeCyj -I- 6HjS0^ = I'e"K,FeCya + 6KHS0, + 6HCy.
Tlie details of ths official process are as follows ; Dissolve 2:^ ounces of fetrocyanide of potassium in 10 ounces of water, add 1 fluidonnce of sulpliiiric acid previously dUuted with four ounces of the water and cooled. Pnt the solution into afiask or other suitable apparatus of glass or earthenware, to which are attached a condenser and a receiver arranged for distillation ; and having put 8 oancea of distilled water into the receiver, and provided efficient means for keeping the condenser and receiver cold, apply heat to the flask, until, hy slow distillation, the liquid in tlie receiver is increased to 17 fluidounees. Add to this 3 ounces of distilled water, or as ninch as may be sufficient to bring the acid to the rennired strength, so that 100 grains (or 110 minims) of it, precipitated with a solution of nitrate of silver {vide paragraphs on quantitative analysis), shall yield 10 grains of dry cyanide of silver.
rAermdweo/' (/lis reaci«o« is acid sulphate of potassium (KHSOJ, which remains in solution, and ferrocyanide of potassium and iron (Fe^'EjEeCyj), an insoluble powder sometimes termed Bveritt's yel- low salt, from the name of the chemist who first made out the nature of the reaction. The latter compound becomes bluish-green during the reaction, owing to absorption of oxygen. Dilvied Itydrocyamc acid may also be prepared by reaction of cjanide of silver and diluted hydrochloric add.
J^re anhydrous hydrocyanic aeid is a colorless, highly volatile, intensely poisonous liquid, solidifying when cooled to alow temper- ature It may be made by passing i sulphuretted hydrogen over mercuric cyanide
Note —A. few drops of diluted hydro' yanic acid so placed that its vapoi may be inhaled, foims the Vapor Acidi Hydrocyanici, B. P., or Inhalation of Hydrocyanic Acid
Hydrocyanic acid also occurs m cheny-laurel water and bitter- almond water {mde Index)
id .y Google
The methocls of detenniiimg the strength of solutions of hydrocy- anic acid will be deacribed in connection with volumeliic and grav- imetric quantitative analysis.
Analytical Beactions (Tests).
First Analytical Meaction. — To a few drops of the hydro- cyanic acid solution produced in the above reaction, or to any solution of a cyanide, add solution of nitrate of silver; a white precipitate of cyanide of silver (AgCy) falls. When the precipitate has subsided, pour away the super- natant 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, and observe that the precipitate is insoluble or only spar- ingly soluble. (Chloride of silver, which is also white, is readily soluble in ammonia.)
Solubility/ of pTecipitate in strong solutions of salts. Cyanide of silver and many other precipitates insoluble in acids or alkalies are often soluble in the strong saline Uquids formed by the addition of a«ids to allialies. Hence Wie precaution of adding the latter re- ' agents to separate portions of a precipitate, or of not adding the one nnfil the other has been poured away.
Cyanogen in an insoluble cyanide, sneh as cyanide of silver itself, is readily recognized on heating the substance in a short piece of glass tubing closed at one end like a test-tube and di-awn out at the other end, 30 as to have but a small opening; on applying a flame, the escaping cyanogen ignites and burns with a charatteristic peach-blossom-tint.
Antidote.
Second Analytical Reaction. — To a dilute solution of hydrocyanic acid, or a soluble cyanide, add a few drops of solution of a ferrous salt and a drop or two of solution of a ferric salt (ferrous sulphate and ferric chloride are usually at hand) ; to the mixture add potash or soda, and then hydrochloric acid; a precipitate of Prussian blue rem. The decompositions may be traced in the following e tions; —
HCy + KHO = KCy -f H,0
2KCy -(- FeSO, = FeCy, + K,SO, 4KCy + FcCy, = K.FeOyg or K.Fcy 3K,Fcy + 2Fe,Cle = 12EC1 + Fe.Fcy,.
The test depends on the c cyanogen by the iron of a feiToi ferrocyanogon, so produced, with the iron of a ferric salt.
id .y Google
233 SALTS OP ACIDULOUS RADICALS.
Hence a mixture of green aalphate of iron, solution of per- chloride of iron, and either magnesia or carbonate of sodium, is the recognized antidote in cases of poiBooing by hydrocyanic acid or cyanide of potassium, In such an alEaiine mixture the poisonous cyanide, by reaction with ferrous hydrate, is at once converted into inuoouone ferrocyanide of potassium or sodium; should the mixture become a d th f salt present reacts with the soluble ferrocjanide forn ng 1 hi Prussian blue, which is also inert. From the rapidity f the a t n of these poisons, however, there is seldom time to pr pa a at dote. Emetics, the Btomach-pump, the application of a t am t cold water to the spine, and the above antidote form the u ual t at meat.
Third Analytical SearMon — To solution of hydrocyanic acid add amnaonia, and common yellow aulphydrate of ammonium, and evaporate the liquid nearly or quite to dryness in a email dish, occasionally adding ammonia till the excess of sulphydrate of ammonium is decomposed ; acidify the liquid witii hydrochloric acid, and then add a drop of solution of a feri'ic salt; a blood-red solution of sulphocyanato of iron will be formed.
This is a very delicate reaction. Some free sulphur in the yellow aulphydrate of ammonium unites with the alkaline cyanide and forms aulphocyanate (2AmCy+8j=2 AmCyS) ; the ammonia combines with excess of free sulphur and forms, among other salts, sulpijydrate of ammonium, the whole of which is removed by the ebullition. If the liquid has not been evapoi-ated far enough, sulphydrate of ammo- nium may still be present, and give hiaok sulphide of iron on the addition of the ferric salt.
HydTocyoma acid in, the blood. — AccoriJing to Buchner the blood of animals poisoned by hydrocyanic acid, instead of coagulating as usual, remains liquid and of a clear cherry-red color for several days. In one case he obtained the reactions of the acid on dilnting and dis- tilling the blood fifteen days after death, and applying the usual reagents to the distillate. Aqueous solution of peroxide of hydrogen {p, 78) changes such blood to a deep brown color.
QUESTIONS AND EXERCISES.
414 Write a paragraph on the history of cyanogen.
415. Mention the source of the cyanogen of all cyanides.
416. How is Ferrocyanide of Potassium prepared!
417. What is the formula of ferrocyanide of potaasmm !
418. Is ferrocyanide of potassium poisonous ?
419.- Write an equation expressive of the reaction wl ch cn^ es when ferrocyanide and carbonate of potassium are bro ght together at a high temperature.
id .y Google
NITRATES. 233
420. What are the properties of cyanogen ! How may it be oli- tained in a pure condition ?
421. How is mercaric cyanide prepared 1
422. How much real hydrocyanic acid is contained in the official liquid ?
423. Give details of the preparation of hydrocyanic acid, and an equation of the reaction.
424. State the proportion of water that must be added to an aque- ous solution containing 15 per cent of hydrocyanic acid to reduce the strength to 2 per caat.—Ans. 6i to 1.
425. What are the characters of pure hydrocyanic acid ? How may it be obtained ?
42e. Enumerate the testa for cyanogen, giving equations. 427. Explain the action of the best antidote in cases of poisoning by hydrocyanic acid or cyanide of potassium.
HrrRIC ACID AKB OTHER NITRATES.
Formula of Nitric Acid HNOj. Molecular weight 63.
Introduction. — The group of elements represented by the formula NOj is that characteristic of nitric acid and all other nitrates ; hence it is expedient to regard these elements as formiae an acidulous radical, which may be termed the nitric radical. Lilte the hypo- thetical basylous radical ammonium (NH,), this supposed acidulous radical (NOj) has not been isolated. Po^ibly it is liberated when chlorine is brought into contact with nitrate of silver ; but if so, its decomposition into white crystalline nitric anhydride (NjO^) aiid oxygen (0) is too rapid to admit of ita identification.
Sources. — The nita'ogen and oxygen of the air combine and ulti- mately form nitric acid whenever a current of electricity (as in the occurrence of lightning) passes. Nitrates are commonly met with in waters, soils, and the juices of plants. Nitric acid and other nitrates are obtained from nitrates of potassium and sodium, and these from the surface soil of tropical countries. Nitrate ofpotassiwm or prismatic nitre (from the form of its crystals) is chiefly produced in and about the villages of India. The natives simply scrape the sur- face of waste grounds, mud heaps, banks, and oUier spots where a slight incrustation indicates the presence of appreeiable quantities of nitre, mix the scrapings with wood-ashes (carbonate of potassium, to decompose the nitrate of calcium always prreent), digest the mix- ture in water, and evaporate the liquor. The impure product is purified by careful recrystallizations, and is sent into commerce in the form of white crystalhne masses or fragments of striated six-sided prisms. Besides its use in medicine [Potaasm Nitrm, B- P- and U. S. P.), it is employed in very large quanlJtieii in tlje maaufa^ture of gunpowder. Nitrate o^ Sodiwin (oodw NiiruB, p. P.) occurs in more distinct incrustltiDpe on the aarfape of the CTOuad ia Peru, Bolivia, anct Obi'j. JPOl* eapepiftUy in the district of Atacama ; it is distiBgiliahe^ ag Chili saltpetre of [from tiie form of its crystals— 20*
id .y Google
234 SALTS OP ACIDULOUS RADICALS.
obtuse rhonilioids) oubic nitre, and is cLieflj used ag a mamire and as a source of nitric acid, its tendency to absorb moistnre unBtting it for B36 io gunpowder. In many parts of Europe nitrate of potas- Biuin is made artificially by exposing heajB of animal manure, refuse, ashes, and Boil to tlie action of the air and the heat of the enn ; in the course of a year or two the Ditrogen of the animal matter becomes oxidized to nitrates, and the latter are removed by washing.
Note. — -The word nitric is from nitre, the English eouivalent of the Greeli iirpov (nitron), a name applied tocertain natural deposits of natron (carbonate of sodium}, for which citrate of potassium seems at firet to have been mistaken. Saltpetre is simply scdpetrce, salt of the rock, in allusion to the natural origin of nitrate of potassium. Sal pruneUa (from sal, a salt, and prana, a live coall is nitrate of potassium melted over a fire and cast into cakw or ballets.
The nitric radical is univalent {NO/).
Constitution of Salts.
It is here necessary again to caution the reader against regarding salts as invariably possessing a known constitution, or suppoeing that they always possess two or more sides, or contain definite radicals. The erroneous conception which, of all others, is most likely to be imperceptibly formed is that of considering salts binary bodies. For, first, the names of salts are nece^arily binary. A student hears the names " sulphate of iron," " snlphate of copper," and simnltaneously receives the impression that each salt baa two sides, copper or iron occupying one and something indicated by the words "sulphate of" the other. Sucli words "vitriol," green or blue, or " nitre," would perhaps implant unitary ideas in the mind; but it is simply impossi- ble to give such names to all salts as will convey the impression that each salt is a whole, and therefore unitary. The name " sulphate of potash" produces binary impressions ; and the less incorrect name, " sulphate of potassium, is in this respect no better. Secondly, it is impracticable to study salts as a whole. Teachers are unanimous in the opinion that students should first master the reactions charac- teristic of the metals in salts, and then the residues which, with those metais, make up the salts, or vice versd. It is not only im- practicable, but impossible, to study salts as a whole ; binaty ideas concerning them are therefore almost inevitably imbibed. We come to regard a salt as a body which splits up in one direction only, look upon nitre, for instance, and all other nitrates, as containing NO3 and a metal, K ; whereas KNO, may be split up into KNOj and O ; or into KjO, Ng, and O5; or may contain K5O and N^O,. These are the chief disadvantages attending the employment of the binary hypothesis in studying chemical compounds : if they be borne in mind, the hypothesis may be freely used without much danger of permanent mental biaa. Thus in nitre let the group of elements (NO,) which, with potassinm, makes up the whole salt be called the nitric radical, the name of the latter being directly derived from ils hydro- gen salt. Similarly allow the acidulous residues of other sails of metals to be termed respectively the chloric, acetic, sulphurous, snl-
id.y Google
NITRATES. 235
Ehuric, carbonic, oxalic, tartaric, phosphoric, citric, boradc radicals, a shoft, these compound radicals should be regarded as groupings common to many salts, and which may nsaally be transferred without any apparent breaking or splitting; at the same time we ranst be prepared to find that occasionally a salt divides in other directions. In this way perhaja erroneous impre^ions will gain least hold on the mind, and a way be left open for the easy entrance of new truths, should the real constitution of salts be discoyered.
Formerly salts (such as sulphate of magnesium) were regarded as containing (a) an oxide of a metal (MgO) and an anhydride (SO,), the latter being incorrectly called an acid (sulphuric add), or (6) as containing two simple radicals [e. g. KI, NaCI, KCy, HgS) — the former being called oxyacid salts, or oxysalts, and the latter haloid salts (from oSlj, als, seasalt, and iBof, eidos, likeness). Such distinc- tion is no longer maintained, the two classes being merged. This ia an important educational gain on the side of simplicity ; for, whereas nnder the old system much time was necessarily expended before salts of a metal and salts of the oxide of that metal could be distin- gaished (e. g. KI and MgO, SO.), now, all salts being regaj-ded as salts of the metals tbemselveB (e. g. KI and MgBO,), no such dis- tinction is necessary.
Reactions. ITitric Acid,
SyntheHeal Beaction. — To a fragment of nitrate of potas- sium or nitrate of sodium in a test-tube add a drop or two of sulphuric acid, and warm ; nitric acid (HNOj) isevolved in vapor. The fumes may be condensed by a bent tube fitted to the test-tube, not by a cork as for hydrochloric acid, because the nitric vapors would strongly act on it, but by plaster of Paris, a paste of which sets hard on being set 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 or plain retort, a mixture of equal weights of nitrate of potassium and sulphuric acid ; the acid distils over, and acid sulphate of potassium re- mains liehind : —
HNO, + KHSO.
Half the quantity of sulphuric acid may be taken ; but in that case neutral sulphate of potassium (KjSOj) is produced, which, from its hard, slightly, soluble character, is removed with difficulty from the retort. On the manufacturing scale the less proportion is used ; bnt instead of retorts iron cylinders are employed, il'om which the residual
'■ ' ;d by chisels. Moreover the cheaper sodium salt is the
id .y Google
236 SALTS OP ACIDDtOUS RA1JI0AI.8.
nitrate from wMcli manufaoturerB uBually prepare nitric acid, seven parts of nitrate of sodium and four of sulpliuric being employed.
Note. — The aeid sulphate of potassium is readily converted into neutral sulphate [Potamce Sulphas, B, P. and V. S. P.) bj dissolv- ing' in water, nddiog carbonate of potassium until effervescence ceases to occur, filtering, and setting aside to crystallise.
Pure nitric acid (HNO,) is a colorless liquid, somewhat difficult of preparation ; its specific gravity is 1.52. The strongest acid met ■with in commerce has a ap. gr, of 1,5, and contains 93 per cent, of real nitric acid (HNOj); it fumes disagreeably, is unstable, and, except as an escharofio, is seldom used. The British and United States Pharmacopeias contain two acids : Acidtim Nitricwm,, pre- pared as above, of Bp. gr. 1.42 falao in TJ. 8. P.), and containing 70 per cent, of real acid (HNO,); and another, Acidwm, Nitricum Dilvium, sp. gr. I.IOI (U. S. P. 1.068), containing nearly lli (1744) per cent Either of tlie stronger liquids, although containing water, IS usually simply termed "nifi-ic acid." The official nitric aeid, of sp. 1.42, is a defluite hydrous acid (2HN0., SH^O) ; it distils at 250° P. without chaage. If a weaker acid be heated it loses water, if a stronger a<iid be neated it loses nitric acid, until the density of 1.42 is reached. Aquafortis is an old name for nitric acid [Aquafortis simplex, sp, gr. 1.22 to 1.25 ; Aqua fortis duplex, 1.36}. The strength of a specimen of nitric add is determined by volnmettic analysis. Nitnc anhydride (^,0^) sometimes, but erroneously called anhydrous nitric acid, is a solid crystalline substance formed on passing dry chlorine over dry nitrate of silver.
Aqua Regia. — Three fluidounces of nitric acid (B. P.), four of hydrochloric acid (B. P.), (3 to 5 by weight forms the Aeidum NUroinuriaticwm,, TJ. S. P.), and twenty-five of water, give the Afidum NitrohydroohlariQum Dilutum of the British Pharmaco- , The acids must be mixed twenty-four hours before dilution sure mutual decomposition and full development of the chief e product, chloriue:—
2HN0, + GHOl = N,0,ai. + 4H,,0 ■+ CL
ntricacl^. Hydiochloi'lc Chlorotillili! Walei'. Clilo^ue.
3H0I = NOCl + 2H.,0 -j- 01,
The same reaction occurs if the acids are mixed after dilution, but is not complete for a week or a fortnight (Tilden). llie undiluted mixture of acids is known as aqua regta, so called from its property of dissolviog gold, the " king" of metals.
Analytical Beactions ( Testa).
First Analytical Reaction.- — -To a solution of any nitrate {e.g. KNOa) add sulphuric acid, and then copper Uwa-
id.y Google
NITRATES. 237
ings, and warm ; colorless nitric oxide gas (NO) is evolved, which at once unites witli the oxygen in the tube, giving red fumes of nitric peroxide or peroxide of nitrogen (NO,).
2KSO, + 5II..SOi+Cu, = 2NO + 3CviSO, + 4H„0 + 2KHSO,; 2N0 + Oj = 2X0,.
Performed on a larger scale, in a vessel to ivhich a dolirery-tubo is attached, this reaction becomes of STiithetical interest, being the process for the preparation of nitric oxide gas for the purposes of cbemical expet-imciit.
Small amounts of a nitrate may be overlooked by this test, the color of the red fumes not being very intense.
Undiluted nitric acid poured on to copper turnings gives dense red vapors of nitrous acid (HNO,), nitroas atihydrate (N^Oj), and nitric peroxide (XO,).
Second Anahjlioal Reaction. — To a colcl solution of the nitrate, even if very dilute, add three or four crystals of sulphate of iron, shake gently for a minute in ovdei" that some of the sulphate may becomedissolved, and then pom- eight or ten drops of strong sulphuric acid down the side of the test-tube, so that it may form a layer at the bottom of the vessel ; a reddish purple or black coloration will appear between the acid and the supernatant liquid.
This is a very delicate test for the presence of nitrates. The black color is due to a solution or, perhaps, combination of nitric oxide with a portion of the fcrrons salt. Tne nitric oxide is liberated from the nitrate by the reducing action of the hydrogen of the sulphuric acid, the sulphuric radical of which is absorbed by the ferrous sul- phate, the latter salt becoming ferric sulphate.
2HNO3 + BHaSO^ + 6FeS0i = 4H,0 + 3(Fes3SOJ -f 2X0.
The process of oxidation is one frequently employed in experi- mental chemistry; and nitrates, from their richiiess in oxygen, but more especially because always at hand, are the oxidizers usually selected for the purpose. la the operation they generally split up in one way, namely into oxide of their baajloas radical, nitric oxide gas, and available oxygen. Thae hydrogen nitrate (nitric acid) yicMs oxide of hydi-ogen (water) and the other bodies mentioned, as shown in the following equation : —
4NH0, = 2n,0 + 4X0 + 30,,
When nitrates, other than nitric acid, are used for the purpose of oxidation, a stronger acid, generally sulphuric, is com nioidy added in order that nitric acid may be formed ; the hydrogen nitrate splitting up more readily than other nitrates.
Nitrate of ammonium (readily formed on neutralizing nitric acid
id .y Google
with carbonate of animonimii), wlieii heated, yields iiilioitx oxide, or laugUIug-gas (N'„0).
NH.NO, = K,0 + 2H,0.
Nitrons oxide is thus prepared for use as an anscsthetic. IVlien rp<|uirctl for inhalation, it should he washed from aiij- possible traee of acid or nitric oxide, by being passed through solution of potash, and through solution of ferrous sulphate.
Nitrous osidc is slightly soluble in warnv water, more so in cold. By pressure it may be liquefied, and by simultaneous cool- ing solidified. It supports comhustiou almost as well as oxygen.
Thefice oxides of nilrogeii have now been mentioned, namely :—
Nitrous oxide N™0 ] fN.O
Nitric oxide* NO N^O,
Nitrous anhydride . . . N,0^ - or -j N^Oj
Nitric peroxide* .... NO5 X.^O,
Nitric anhydride . . . . N^J L^'A
The two anhydrides by absorbing water vield respeefivolv nitrous aeid (HXO„) and nitric acid (HNO,,). this series of compounds forms a good illustration of the doctrine of multiple pi-oportious (p. 3G).
Third Analytical BeacHon. — Direct the blowpipe-flame on to charcoal until a spot is red-hot ; now place on the spot a fragment of a nitrate ; deflagration ensues.
This reaction does not distinguish nitrates from chlorates. It is insufficient for the recognition of very small quantities of either class of salts, especially when they are mixed with other substances.
Gunpoieder is on intimate mechanical mixture of 75 parts of uitre, 15 to 12^ parts of charcoal, and 10 to 12i parts of sulphur. In burning it may be said to give sulphide of potassium ( the while smol(e, K.^), nitrogen (N), carbonic oxide (CO), and iiu ■■ ni' n. M .* U,) gases, though the decomposition is Heldoni cumi |. I'. ■■ iil.u
produclion of a large quontity of heated gas fi< '1 1 ! in 1 ; ly
of a cold solid is aufiicient to account for all the eth . i- i' u .'i ;!':■■■. idi-.
Fourth Analytical Reaction. — To nitric aiid or oilier nitrate atlcl solution of " sulphate of indigo ;'' tlio color is discharged.
" Solution, of Sulphate of Indigo," B. F. (Sujpliindylio or Sul- phindigotic Acid), is made by digesting 5 grains of dry finely pow- dered indigo in a small quantity of strong sulphuric acid in a test- tube for an hour, the mixture being kept hot by a w.iter-liath ; the blue liquid is then poured into 10 ounces of sulphuric acid, the whoic
id .y Google
NITRATES. 239
well shaken, set aside, and the clear Jiqaid decanted. Free chlorine also destroys Ihi' color of this reagent.
In'liqn a. P. (U3if*0) is a blue coloring'-inatter deposited when itifnsion of various species of Indigo/era is exposed (o air and slight nirmth Under those circamstances, t'ndican, & yellow transparent amorphous substance, soluble in water, breaks up iuto indigo, which is iniolnble and falls as a sediment and a sent of sugar teimed indi g!uein The indigo is collected drained pre sed nnd driel Rv action of deoxidizing agents indigo la conceited uit I H I il tndtgogen, reduced iiidigo oi tthtle indigo ! ; i 1
indigo, 2 of green "sulphate of iron 3 of sinl 1 water, shaken top'ether and set aside m a well I this colorless indigo A piece of jarn calit dipped into such a solution and exposed to an I dej s t on of nsol He nd goblne occumugnill i
slsoftl fibv Ihsojerto is reidiiy (wit fi le I f a ! On trat n of the cb m i i i I
the a t I I (1 utroduction of solul I I u i n iltir
i t I 1 I f the walls of its cellular and lascular
t a u I of that coloring matter by conTcrsion
into II I {it le also p IWJ
B I t ac d and other ndi ales — Presence of
the tr rjd al u aolat on hav ng been proved by the above rea<.t ois ts occurrence as the trate of a metal is demonstrated by tl neutral or earl v neutral d lortmeut of the liquid with test- pa) e a I the detect o of the metal— its occurrence as nitric acid by the sourness of the liqaid to the taste and the effervescence pro- duced on the addition of a carbonate.
Antid(ite.~la cases of poisoning by strong nitric acid, solution of carbonate of sodium (common washing-soda) oramixtureof uiaguosia aud wnlcr may be administered as antidotes.
QUESTIONS AND EXERCISES.
om prismatic
430. Describe a process by which nitrate of potassium may be obtained artificially.
431. State the difference between niti-ate of potassium, nitre, salt- petre, and sat prunella.
432. What gronp of elements is characteristic of all nitrates? and what claim has this group to the title of radical ?
433. Mention the usual theory regarding the manner in which atoms are arranged in reference to each other in such salts as nitrate
434. How is Xitric Acid prepared ?
435. (Jivethe properties of nitric acid.
436. "Wlmf reactions occur when slrong nitric atiil liydi'ocliloi-ic acids nre mixed?
id .y Google
240 HALTS or ACIDULOUS RADICALS.
43". How is nitric oxiJe prepared?
438. Kinimerate aud explaiQ the teats for nitrates.
439. Into wliat subataQcea does nitric acid usually split nhe ployed as an oxidizing ageut !
440. How is nitrona oxide prepared ?
441. Enumerate the five oxides of nitrogen.
442. "What is tiie nature of gunpowder ?
443. Write a few sentences on the chemietry of imligo, one o tests for nitric aoid.
444. How ia nitric acid distinguished from other nitrates ? 44o. What qnautity of cubic nitre will be required to produc
carboys of official nitric acid, each containing 114 pounds!— lUTGj^ pounds.
CHLORIC ACID AND OTHER CHLORATES.
Formula of Chloric Acid HClOa. Molecular weight 84.5.
Hypoohlorous Acid (HCIO), and other Hypochlorites,
Place a few grains of red oxide of mercury in a test-tube, half-flll the tube with chlorine-water and well shake the mix- ture ; the resulting liquid is a solution of hypochlorous acid, mercuric oxychlorido remaining undissolved : —
2HgO + 2CI, + H,0 = 2HC10 + Hg.OCl,.
By the double decompo.sition of hypochlorovis aoid and oxides or hydrates, other pure hydrochlorites are formed ; —
IICIO + KaHO = XaClO + H,0.
The direct action of chiorine on metallic hydrates is sup- posed to give a mixture of chloride and hypochlorite, as described in connection witii the synthetical reactions of Sodium (p. 61, Liquor Sodse Chloratx, B. P.) and Calcium (p. 84, Calx chloraia, B. P.).
CI, -i- 2XaII0 = NaCl,XaC10 -f II.O ; SCIj -f 2CaH,0, = CaCl,,Co2C10 + 211^0.
But the presence of chlorides cannot be directlj' demon- strated in these bodies ; so that their constitution is not definitely determined. The action of acids on them results in the evolution of chlorine ; hence the great value of the calcium compound (chlorinated lime, or chloride of lime) in bleaching operations : —
CaCl„Ca2C10 + 2II,S0. = 2C1, + 2CaS0, + 2H^0.
id .y Google
CHLORATES, 241
The solubility of Uypoelilorites in water, tlieir peculiar odor, greatly intensified on the addition of acid, and their bleaching-powers (see the above calcium reaction) are the characters on which to rely in searching for hypochlorites.
Chlorates.
Tl>e group of elementary atoms represented by tlie formula CIO, is that characteristic of eliloric acid and all other chlorate?; hence it is expedient to regard it as being an acidulous radical, which may be termed the chloric radical. Like the nitric radical, it has not been isolated. Chloric anhj'dride also (Cl,0;), nnllke nitric anhy- dride, has not yet been obtanied in the free condition.
Chlorates are artificiai salts. They are formed bv simply boiling aciacous solutions of the common bleaching salts (chlorinated lime, chlorinated soda, chlorinated potash). Heat thus converts
3(KC1,KCI0) 1 f EClO, 1 ( 5KG1
3(CaClj, Ca2Cia) ] . f Ca2CI0, | j SCnCIs
One chlorate may also be made from another by double decomposi- tion. In making chlorates economically the chlorinated salt is spe- cially prepared for, and in the same \essei as, the chlorate.
Chlorate of Potassium, Thus Chlorate of Potassium (Puiossic Chloras, B. P. and U, S, P.) is commercially made by saturating with chlorine gas a moistened mixture of three parts of chloride of potassium and 10 of slaked lime, and well boiliug the pro- duct. Chlorinated lime is first formed; this, on boiling with water, splits up into chloride of calcium and chlorate of calcium, and the latter reacting on the chloride of potassium yields chloride of calcium and chlorate of pot as-
6{Ca2HO) + GCl, = 3{CaCl„Ca2CIO) + CILO; 3(CaCl„Ca2C10) = CaSClO, + 5CaCl,; CaSClO, + 2KC1 = CaCl^ + 2KC10,.
The operation may be conducted on a small scale by rub- bing together in a mortar the above proportions of ingre-
id.y Google
242 SALTS or acidulous radicals.
clients in ounces or half-ounces, adding enough water to make the whole assume the character of damp lumps, placing the porous mass in a funuel (looselj' plugged with stones or pieces of glass) and passing chlorine gas (p. 15) up throngh the neck of the funnel. When the whole mass has become of a slight pink tint («lne to a trace of perman- ganate) it should be turned into a dish, well boiled with water, filtered, tbe filtrate evaporated if necessary, and set aside ; the chlorate of potassium crystallizes out in color- less rhoinboidal plates, chloride of calcium remaining in the mother- liquor.
In the official process, carbonate of potassinm instead of chloride is Tispd; but otherwise it is similar to the method just described. Chlorinated potash and chlorinated lime are first formeii—
K,CO, + Ca2H0 + CL = KCl. KCIO + CaCO, -f H.O,
6(Ca2HO) + 6C1, = 3(CaClj,Ca2C10) + 6H,0i
these, on boiling- with water split np into chlorates and chlorides —
3(KC1.K010) = KCIO, + .^KCl
3{CaUVCa2C10)= Ca2C10i + oCaCI,,
the whole of tho chloride of potassium and chlorate of calcium
finally yielding chlorate of potassium and chloride of calcium,
2KC1 + Ca2C103 = CaCL, + 2KCIO3.
Chlorate of potassinm is soluble in water to the extent of 6 or 7 parts in 100 at common temperatures. It is usually adminislcrcd medicinally in aqneons solution, sometimes also in lozenges ( Tra- chi'sci PotaBst^ Chlomfis, B. P.). Chlorate of potassiinn must, on no account, be rubbed with snlphnr in a mortar, friction of such a mixture resalting in violent explosion.
Chlorate of potassium, when heated, yields chloride of potassium and oxygen, and ia the salt commonly employed in the preparation of the gas for experimental purposes. But if the action be arrcated when one-third ef the oxygen has escaped, the residual salt is found to contain perchloi-ate of potassium (KCIOjj : —
2KCIO3 = KCIO4 + KCl + O,.
Chloric achl (HCIO,) may be isolated, but i; decom porting iulo chloriiu', oxygen, and peruhlorii
id .y Google
CIILOEATES. 21S
chlorate [p. y. Ki'lO^,) must thuivfore be upocI in atiiiiyiiig the reac- tions of tlio clilocic radical. PurMorio add (IICIO^) may be obtained by distillijia' perehloratc of potassium with sniplmric acid ; it is quite stable, and is occasionally administered in mcdiciae.
Table of the Chlorme An,h.
Hj'<3rocliloi'ic acid . . . , IK 'I Hypoclilorous acid .... IICIO.
utki '.'.'.'.'. wiwi
Analytical Reactions {Tents).
First Analytical Reaction. — To soSution of a clilorate (e.g. chlorate of potiissiura) add solutiou of nitrate of sil- ver; no precipitate falls, showiug that the chlorine miiat be performing ctifferent functions to those it possesses in chlorides. Evaporate the solution to dryness, and place the residue in a small dry test-tnbe, or at once drop a fragment of a chlorate into a test-tnbe, and heat strongly ; oxygen is evolved, and may be recognized bj' its power of reinflaming an incandescent match inserted in the tnbe. Boit the residue with water, and again odd solution of nitrate of silver; a white precipitate falls, having all the characters of chloride of silver, as described under hydro- chloric acid.
This is a trnstn-crfl\y te?t. and, omitting the recognition of the oxygen, may be applied in llio detection of small finaiitities of chlorates.
Second Analytical Reaction. — To a fragment of a chlorate add two or three drops of strong siilj>hHric acid ; an explo- sive gas (Cl.,0,) is evolved, having a peculiar odor some- what like chlorine, but deeper in color than that element.
3KC10, -1- H,SO. = Gl^O, -f KCIO, 4- K,SO^ + H,0.
Warm the upper part of the test-tube to ISO^" or 200° P., or introduce a hot wire ; a sharp explosion ensues, due to decomposition of the gas, peroxide of chlorine, into its elements.
T/iinl Analytical Reaction. — Heat a sm.all fragment of a chlorate with hydrochloric acid ; a yellowish-green ex-
id .yCoOglc
244 SALTS or ACTPULOUS RADICALS.
plosive gas termed exichlorine, is evolved. Its color ia deeper tban that of chlorine, hence the name (from ,i, eu, well, and ;[j,upos, chl&ros, green). In odor it resembles chlorine, and ia probably a mixture of that element with one of the oxides of chlorine.
Fourth Analytical Reaction. — Direct the blowpipe-flame on to charcoal until a spot is red-iiot, and then place on the spot a fragment of a chlorate ; deflagration ensues as with nitrates.
lodates.
Iodic Acid (HIOj). -"Iodine is boiled with several times its weijrht of strong- nitric acid, in a ftime-onpboard, until all action ceases. The liquid is evaporated to dryness to remove excess of nitric acid, the residne dissolved iu a small quantity of boiling water and the solution set aside to crystallize.
lodfife of Potassium (KIOj). — Powder tojrethcr eqna! weights of iodine and chlorate of potassium ; to the mi.^tnrc add twice its weight of water and about one-eighth of its weiglit of nitric acid ; warm the whole until iodine disappears, and evaporate quite to drj-ness over a water-bath. The residue dissolved m water fonns "Solution of lodate of Potash," B. P. (1"he reaelion is complicated. Vide Na- quet's Modern Chemistry, Eng. edit. p. JOT.)
Ferric lodate, or rather Oxyiodate (Fe,04I0,. 8H,0), is precipi- tated on adding solution of ferric chloride to solution of iodate of
QUESTIONS AND EXERCISES.
446. How may hypochlorous acid be formed?
447. What are the relations of hypochlorous acid to c bleaching powder ?
448. By what reaction is chlorine eliminated fi-om hypochlorites?
449. State the general reaction by which chlorates are formed. 430. Give details of the preparation of chlorate of potassium.
451. Mention the properties of chlorate of potassium.
452. What decompositions occur when chlorate of potassium is heated?
453. Find the molecular weight of chlorate of potassium.
454. What weight of o.vygen is yielded when 1 oz. of chlorate of potassium is completely decomposed, and how much ohloride of potas-
455. One hundred cubic inches of oxygen, at 60° F. and barometer
id .y Google
ACETATES. 245
at 30 inches, weifrhinp 34.203 frraiiis, and 1 gallon containing 277^ cubic iuoliea, what weight of chlorate of potassium will be required to yield 10 gallons of the gas ? — ins. aj ozs.
45f). How many cubic inches of o-xj-gen are producible from 1 oz. of chlorate of potassium !
457. Calculate the weight of chlorate of potassium theoretically obtainable from 100 parts of chloride.
458. How is perchloric acid prepared ? 4,i9. Enumerate the chlorine acids.
4(i0. Hoiv may the presence of chlorides in chlorates be ilcmon- Btrated ?
461. Mention the tests for cliioratcs.
462. Give the formula of peroxide of chlorine.
463. Whatis euchlorine?
464. How may iodic acid be made ?
4Go. Describe" the preparation of iudato of potajsiuiii.
ACETIC ACIB Aim OTHER ACETATES.
Formula of Acetic Acid B.C.fis.% w HA. Molecular weight GO.
Source. — Acetic acid ia said fo occur naturaliy in certain plant- jnioea and animal fiuids in minute proportions, but otherwise is an artificial product. Much is furnished by the destructive distillation of wood, hence the term pyroligneouH add for the crude product, a hybrid word from itif,^1lr, fire, and lignum, wood. In Germany and France large quantities are made by the Bpontaneous oxidation of the alcohol in inferior wines, hence the white- and red-tviite vine- gar {vinegar, from the French fin, wine, and aigre, sour). In Eng- land also the domestic form of acetic acid (brown vinegar) has a similar origin ; infusion of malt and uumaltod grain ia fermented ; and the resulting oxidation of its sugar, instead of being arrested when the product is an alcoholic liquid, a sort of beer, is allowed to go on to the next stage, acetic acid ; it usually contains from 3 to G per cent, of real acetic acid (HCjHjO.).
Vinegars. — The official vinegar (Acdum, B. P. and U. S. P.) contains nearly 5J (5.4) per cent. The so-called Vinegar of Oan- tharides {Acetum Cantharidis, B. P.) is a solution of the active principle of eantharides in very strong acetic acid, not in vinegar. The Vinegar of Squill (Acetum Snlix, B. P. and U. S. P.) is also 8 solution of the active principle of squill in dilute acetic acid, not in true vinegar. The same may be said of Acelum Colcliici. V. S. P., Acetum Lobeltte, U. S. P., Acetum Opii. U. S. P., and Aeelvm SangvinaricE, U. S. P. (Vinegar of Bloodroot). Distilled vinegar {Acetum DesfUlatum, V. S. P.) is a form of Dilute Acetic Acid not now official in Great Britain. The Acetum OpH or Black Drop of America is made from nutmeff, saffron, and sugar, as well as Opium and Diluted Acetic Acid. In the British Pharmacopeia, vinegar, 21*
id .y Google
246 SALTS OP ACIDULOUS RADICALS.
except its nse for its own sake, is only emplojed in the preparalioQ of Emplastriint Cerati Saponte,
The Acetic Radical. — The gronp of elcnienta represented by the formula CjHjOj is that characteristic of acetic acid and other ace- tates, and may, for convenienc* of study, be ttssnmed to be an acidn- lous univalent radical. It has not been isolated, unices indeed a compound of similar composition, resulting' from the action of perox- ide of barium on acetic anhydride, is the radical in question. ■ CjH,0„ the characteristic grouping in acetates, is frequently con- sidered h> contain, rather than to be, a radical — CjHjO, termed aceti/l. Acetates may be made to yield a body having the composi- tion CjHjOCl, which is regarded as chloride of acetyl ; from this may be obtained acetic anhydride (C,H,Oj), which by absorbing water becomes acetic acid.
aH,01 C,H.01n C,H,01r. C,H,0 1 ^ CI f C,H,0 J " H I '^ JI I "
Chloride of A<^etie Acelic acid. Ststallio
Heelfl. SD hydride. acf tales.
The relation of acetic acid to alcohol will be evident from the fol- lowing equation representing empirically the formation of the acid; — C,H,P + O5 = C,H,0, -f 11,0
Acetic Acid.
Synthetical Reaction. — To a few gfains of acetate of sodium ill a test-tube add a little water aud some sulphuric acid, and heat the mixture; acetic acid is evolved, and may be condensed by a bent tube adapted to the test-tube by a cork in the usual way.
Acetic Acid. — This is the process by which acetate of sotliam or calcium (the neutralized prodncts of the distillation of wood) is made to yield acetic acid on the large scale. As with nitric and hyiiro- chloric acids, the loose term " acetic acid" is that nsnally applied to aqueous solutions of acetic acid. The Aeiduni Aceticum, B. P., contains nearly 33 per cent, of real acid— that is, of HCjHjOs; for it contains only 28 per cent, of acetic anhydride (C,H^Oa). Its specific gravity is 1.044, the specific gravity oZ Acidmn AceUeum, U.S. P., being 1.047, Acidum Aceticum Dilutum. B. P. and U. S. P., contains 4^- per cent, of nC,H,Oj. Glacial acetic acid (HCjHjOj) contains no water. It solidifies to a crystalline mass at temperatures below 63P P., hence the appellation glacial (from glaeies, ice). Good commercial glacial acetic acid [Actdiita Aceticwm Glaciale, B. P.) does not contain more than 1 per cent, of water, corresponding to 84.15 per cent, of acetic anhydride ; it solidifies at 34°, and again liquefies at 48°: its specific gravity is 1.065. Although water is lighter than this acetic acid, yet the addition of water at first renders the acid heavier ; evidently thcrefoi-e condensation, or contraction in bulk, occurs on mixing the liquids : after 10 per cent, has been added,
id .y Google
ACETATES. 24T
Ihe addition of more wnter prodnces the usnal effect of dilution of a heavy liquid hy a lighter, namely, reduction of relative weight. This matter will lie better understood after the snbjeet of specific gravity has been studied.
The following equation is expressive of the above reaction: —
]S''aC.,H,0, + H,SO, = HOjHjO, + NaHSO,
or, assaniing the existence of acetyl (C.jHjO) in acetic acid, and a . corresponding radical sulpimryl (SOj) in anlphuric acid,
OT, thirdly, on the assumption that salts contain the oxide of a bnsy- lous radical united with the anhydride of an acid (the old view nndcr which snch names as acetate of soda were formed),
Na,0,C,H^Oj + 2H,0,S0, = Na,0,HA2S0j + II,0,C,H„Oj. A'o^e on Constitution of Salts.
Which of these three equations, or, more broadly, which of the three views of the constitution of salts iilustrated by the eqaations, is correct, it is impossible to say. Whether it is C^HjOj, OjH^^O, or C.HjOj, which migrates from one acetic compound to another, whether it is SO^, SO,, or SO,, which migrates from one sulphuric compound to another, and so on with other acidnlous eronpings, cannot at present be determined. There are strong objections to each view; and possibly neither is right. Either the given radicals cannot be isolated, or application of the forces of heat, light, and electricity do not confirm views arrived at by the results of operations with the chemical force ; or a salt comes to be regarded as having so large a number of constitnent parts that the view, however true, breaks domi in practice from the sheer inability of the mind to grasp the complicated analogies involved. Tet for the purposes of description, study, and conversation some system must be adopted- Let the first, then, be generally taken, over-reliance on it being checked by the use of general instead of special names for the hypo- thetical radicals, and other systems be employed in certain cases. (See also p. 243.)
Impurtfi/.—Acctic acid often contains sulphurous acid. The method by which this impurity is detected will be described hereafter in connection with sulphurous acid.
Analytical Reactions ( Tasts).
First Analytical Reaction, — To an acetate acUl sulphni'ic acid and heat the mixture; acetic acid, recognized by its odor, is evolved.
id .y Google
218 SALTS or ACIDULOUS RADICALS.
Note 1. — Iodine, sulphurous acid, and other substances of power- ful odor mask that of acetic acid ; they must be remoTed, therefore, usually by precipitation or oxidation, before appl^iug this test.
Note 3.^It will be noticed that tliia reaction is identical with tlie previous one ; it has synthetical ov analytical interest, according to the object and method of its performance.
Second Analytical Reaction. — Repeat the above action, a few drops of spirit of wine being added to the mixture before applying heat; acetic ether (acetate of ethyl, CgHjC^HjOJ, also of characteristic odor, is evolved.
The basylous radical ethyl (O^H^) will be referred to subsequently.
Third Analytical Seaction. — Heat a fragment of a dry acetate in a test-tube, and again notice the odor of the gaseous products of the decomposition ; among them is acetone (CaH|,0), the smell of which is characteristic. Car- bonate of the metal remains in the test-tube.
Fourth Analytical Seaction. — To a solution of an acetate, made neutral by the addition of acid or alkali, as the case maj' be, add a few drops of neutral solution of perchloride of iron ; a deep-red liquid results, owing to the formation of ferric acetate (Pe,6C,H,0J.
Note. — It will be noticed that the formation of characteristic pre- cipitates, the usual method of removin" radicals from solution for recognition, is not carried out in the qualitative analysis of acetates. Tliis is because all acetates are soluble. Acetate of silver { AgO^HjO,) and mereurous acetate (HgOjH.Oj) are onl^ sparingly soluble m uold water, but the tact can seldom be utilized m analysis. Hence pecu- liarities of color and odor, the nest best characters on which to rely, are adopted as means by which acetates maybe deteited. Acetates, like other org-anic compounds, char «iion heated to a high tcmpera-
QUE8TI0NS AND EXERCISES.
46fi. "What is the formula of acetic acid ?
46". State the relation of acetic acid to other acetates.
408. What is the molecular weight of acetic acid ?
469. Name the sources of acetic acid.
470. What is pyroligneous acid ?
471. From what compound is the acetic acid of foreign and Eng- lish vinegar immediately derived?
472. How much real acid is contained in ofRcial vinegar ?
473. What is the nature of the "Vinegars" of Pharmacy ?
474. How may acetic acid be obtained from acetate of sodium!
475. How much rea! acid is contained in the ofEcia! acetic acid?
id .y Google
SULPHIDE
476. Mention the strength of commercial glacial ncctic acid.
477. Give three or more views of the constitution of acetates, illustrating each hy formalfe.
478. Enumerate the tests foi' a^^elates.
HYDROSULPHTTRIC ACID AND OTHER SULPHIDES-
Formula of Ilydrosulphuric Acid H^S. Molecular weight 34.
Source and Varieties. — The aciduioos radical of hi/drosutphuric acid, sulphydric acid, or sidj^iiretted hydrogen and other sulphides, is the element sulphur (S). It occurs in nature in combinntioti with metals, oa already stated m describing the ores of some of the metals, and also in the free state. Moat of the sulphur used in medicine is imported from Sicily, where it occurs chiefty nsaociated with blue clay. It is purified by fusion, sublimation, or distillation. Melted and poured into moulds, it constitutes a crystalline mass termed roll sulphur. If distilled and the vapor carried into large chambers, so that it may be rapidly condensed, the crystals are so minute as to give the snlphur a pulverulent character; this is euhlimed sulpltitr (Swlphv^ Sublimatim, B. P. and U. S. P.) or flowers of Bidpkw : the same washed constitutes Sulphur Latum, U. S. P. The third common form, milk of sulvhur, will be noticed sabsequently. Sul- phur also occurs in nature in combination as a constituent of animal and vegetable tissues, as sulphurous acid gas (SO,) in volcanic vapors, and as sulphuretted hydrogen in some maters, as those of Harrogate,
Quanfivatence. — Sulphur is sexivalent, as seen in sulphuric anhy- dride (80,), a substance which will be noticed under sulphuric acid. It also occasionally exhibits quadrivalent (SO,) aud still ofteuer bivalent afBnities (H.,S).
Acid Salts. — Sulphur (S") being the first acidulous radical of bivalent activity met with in these sections on acids, it is desirable here to draw attention to a new class of salts to which such a radical will generally give rise. These are acid salts, which are intermediate between normal salts and a«ids. Univalent radicals with an atom of hydrogen give an acid, and with an atom of other basylous radicals an ordinary or normal salt. But bivalent radicals, from the fact that they give with two atoms of hydrogen an acid, and with two atoms of univalent metals a normal salt, may obviously give intermediate bodies containing one atom of hydrogen and one atom of metal ; these are ap- propriately termed acid salts : they are neither normal acids nor normal salts, but acid sails. (Examples :— KHCOj, NaHSO,, KHC,H,0„ Na^HPO., OuH AsOj, 0aH,2P0j.) Whether or not these stlts give an acid reaction with blue litmus paper depends on the stren tl of the respective radicals. Usually they do redden the test pap bnt sometimes not ; thus the acid sulphide or sulphvdrate of p tv um (KH8), of sodium (NaHS), or ammonium (AmHS) has alkal no properties.*
*■ Some chemists regard these snlpbyiratfis as compou \ f b lous radicals with HS, a uuivaleiit grouping termed hydrosulphyt
id .y Google
250 SALTS OF ACIDULOUS aADICAL3.
Syniheiical Beaclions.
Sulpitaretted Hydros n.
First Synthetical Reaction. The preparation of siilpliii-
retted hydrogen, — This operation was descvibed on page
69, and probably has already been studied by the reader.
Precipitated Sulphur, Second Synthetical Reaction. — Prepare the variety of the radical of sulphides known as Prp,cipiiated Sulphur {Sul- phur Prsecipilatuni, B. P. and XJ. S. P.) by boiling a few grains of flowers of sulphur (6 parts) with slafeed lime (3 parts) (10 parts U. S. P.) and some water (20 parts) in a test-tube (larger quantities in an evaporating-basin), filtering, and (reserving a small portion of the filtrate) adding dilute hydrochloric acid until the well-stirred liquid has a faint acid reaction on test-paper ; sulphur is precipi- tated, and may be collected ou a filter, washed, and dried (at about 120°). Excess of acid must be avoided, or hydros ulphyl, the liquid persulpliide of hydrogen (H^S,) will be formed, causing the particles of sulphur to aggre- gate to a gummy mass.
This ia the process of tlie Pharmacop<eias. PoJjsulpliide of cal- cium and hyposulphite of calcium are formed; —
SCaHjO, + eS, = 2CaS5 -f OaS.O, + 3Bfi HjdrHlo of Bnlpliiir. Poljanlpbido Hj-iiosulphlta Water,
Poljsulphide of calcium alone would yield sulphuretted hydro- gen as well as salpliur on the addition of acid. HyposulpUite of calcium alone would yield sulphurous acid gas as well as sulphur. If these gases are formed in the above operation, thej at once react and give sulphur and water, very little, if any, sulphuretted hydro- gen escaping.
4H^ + 2S0j = 3Sj + 4H,0.
(peraulphideof hydrogen, H,Sj), just aa hydrates are similarly viewed IIS oomponnils of the uuivaleiit radical liyrtrosyl (HO) (peroxide of hydrogen, HjO^),— HjS becoming HHS or HHs (liydrosulpliylide of hydrogen), and H,0 becoming IIHO or Hllo(hydioxylido of hydrogen).
id .y Google
Impure Prp.cipitaied Sulphur. — To a sulphur solution prepared as before (or to the reserved portion) add sul- phuric acid; the precipitate is in this case largely coiitam- iuated with sulphate of calcium:—
2CaS, + CaS,0, + 3H SO, = 3CaS0, + 3H,0 + GS,
PoLysulpbiJo Hyposulphile SulpWrlc Sulphale of Waicr. Sulfliar.
Place a little of each of these specimens of ijrecipitated sulphur with a drop of the supernatant liquid on a strip of glass, cover each spot with a piece of thin glass, and exa- mine the precipitates imcler a microscope; the pure sulphur will be found to consist of minute grains or globules, the impure to contain comparatively large crystals (sulphate of calcium).
Note. — By far the larger projtortion of precipitated aulpliar met ■with in commerce is still (1871) adulteratecl with sulphate of calcium, most specimens contaioing two-thirds of their weight of that suli- stance. Moreorer, this adulteration has heeu so persistently pi'ac- tiaed that many persons have become sufficiently accustomed to the ■ Batiny appearance of the impure article to regard the pure article with suspicion, sometimes refusing to purchase it.
To ascertain the amount of sulphate of calcium in an impure speci- men of precipitated sulphar, place a weighed quantity in a tared crucible and heat till no more vapors are evolved. The weig-lit of the residual anhydrous sulphate of calcium (CaSO,= 136), with one- fourth thereof added, is the amount of crystalline sulphate of calcium (CaSO„ 2HiO = 172) present in the original quantity of impure
Pharmacists should refuse all parcels of sulphur which yield a white ash when a little is bunit off on the end of a table-kuifc or spiitnla. (Ko more damage is done to the steel than a rub on a kiiilo-boai-d will remove.)
Analytical Reactions (Tests).
To a sulphide add a few drops of hydrochloric acid; Bulphuretted hydrogen will probably be evolved, well knowii by its smell. If the sulphide is not acted upon by the acid, or if free sulphur be under examination, mis a minute portion with a fragment of solid caustic potash or soda, and fuse on a silver coin or spoon. When cold, place a drop of dilute hydrochloric acid on the spot, sul- phuretted hydrogen is evolved, and a black stain, due to sulphide of silver (Ag^S), left on the coin.
Other sulphur reactions maybe adopted as tests, hut the ahove are sufficient for all ordinary purposes. The most convenient re-
id .yCoOglc
252 SALTS OF ACIDULOUS EA1>ICALS.
agent for detecting sulphur in solution of ammonia i
sulphate of copper, which gives a black precipitate of sulphide of
sopper if sulphur be present.
QUESTIONS AND EXERCISES.
479. In what form does sulphur occur in nature ?
480. State the modes of preparation of the three chief commercial varieties of snlpluir.
481. To what extent does the atom of sulphur vary in quoiitiva- lencei
482. State the relations of acid salts to acids and to normal salts.
483. Define sulphides and sulphydrates.
484. Describe the preparation of sulphuretted hydrogen.
485. What are the characters of pure precipitated sulphur!
486. Give equations explanatory of the reactions which occur in precipitating sulphur according to the official process.
487. Describe the microscopic test for impure precipitated ealphHr.
488. Mention a ready physical method oT detectiug the adultera- tion of preci])itated sulphur by sulphate of calcium.
489. Mention the tests for BQlpnides, and the character by which Bulphuretted hydrogen is distinguished from other sulphides.
490. How are sulphides insoluble in acids tested for sulphur?
491. Give a method for the detection of a trace of sulphur in solu-
SULPHTTEOTTS ACID ANH OTHEE SUIPHITES.
Pormula of sulphurous acid H^SO.,. Formula of sulphurous acid gas
or salphurouE anhydride, commonly termed sulphurous acid, SOj.
Molecular weight of sulphurous acid 82.
When sulphur is burned in the air it combines with oxygen and forms sulphurous acid gas (SOj), more correctly termed sulphurous anhydride, or commonly, bnt erroneously, sulphurous acid. It is a pungent, colorless gas, readily liquefied on being passed through a tube e.-iternally cooled by 6,freezing-vnscturc composed of two parts of well-powdered ice (or, better, suow) with one part of common salt. If sulphurous acid gas becomes moist or ia passed into water, heat is evolved and true sulphurous acid (^HjSOj) formed. The latter body may be obtained in crystals ; but it la verr unstable, and hence the properties of tlie sulphurous radical must be studied under the form of some other sulphite ; sulphite of calcium (CayOj), or sul- phite of sodium (Na^SOgjimay be used for the purpose.
guffn((Vaience.— The radical of the sulphites is bivalent (SOj"), and hence forms acid sulphites, such as acid sulnhite of potassium (KH8O3) and normal sulpnites, such as sulphite ot sodium (NajSO,).
Note on Nofnenclature. — The sulphites are so named from the
id, Google
5 U L I> II I T E fi , 253
usual rule, that salts corresponding with acids whose names end in ous have a name ending in ite. They are generally made bj^ pass, ing anlphnrons acid gas over moist oxides or carbonates — in the latter case carbonic acid gas escaping.
Synlhelical Reaction. — To a few drops of sulpliuric acid ill a test-tulje add a piece of charcoal and apply heat ; sul- phurous acid gas is evolved, and may be conveyed by a bent tube into a small quantity of cold water in another test-tube. Larger quantities may be made in a Florence flask. The product is the Acidum Sulphtirosum, B. P. and TJ. S. P. It is said to contain, if saturated, nearly 12 (11.79) per cent, of sulphurous acid (H^SO,), or about 9 (9.2) per cent, of the gas (SOJ. The process is also that described in tlie Pharmacopceia, except that the gas is purified by passing through a small wasli-bottle before flnul collection. Specific gravity 1.04 (1.035, U. S. P.).
If in this process the water were replaced by solutions of or solid metallic oxiilesorcarboiiates,sulphite3oftlie various metals would be formed. The formula of sulphite of sodium (Sodce Salpkis, U. S. P.) is Na,S03.7H30 i of the bisulphite or acid sulphite NaHSOs. The former is used for removing traces of chlorine from paper pulp, and is termed antichlor.
4H,S0. + C, = SCO, + 4H,0 + 480, SO, + H,0 = H,SO,
Analytival Reactions (Tests).
fSre/ Analij/ical Reaction. — To a sulphite add a drop or two of dilute hydrochloric acid ; sulphurous acid gas escapes, known by its peculiar pungent smell.
This smell is the same as that evolved on burning lucifer matches that have been tipped with sulphur. It is due, pr^ably, not to the gas (SOj), but to sulphurous acid (IIjSO^) formed by the union of sulphnrous acid gas with either the moisture of the air or that on the surface of the mucous membrane of the nose. It is highly suffo- cating.
Second Analytical Reaction. — To a sulphite add a little water, a fragment or two of zinc, and then hydrochloric acid ; sulphuretted hydrogen wilt be evolved, known by its putrid odor and action on a piece of paper placed like a cap on the mouth of the test-tube, and moistened with a
id .y Google
254 SALTS OP ACIDULOUS RADICALS.
drop of solution of acetate of lead, black sulpliide of lead bfiug forinecl. Sulphurous acid may be detected in acetic acid, or in hydrochloric acid, by this test.
H,SO, + Hg = H^S + 3H^0.
Olher Analytical Reactions.
To solutions of neutral snlphites add nitrate or cliloride of barium, cliloride of calcium, or nitrate of silver; in each case white sulphites of the various metals are preci- pitated. The barium sulphite is soluble in weak hydro- chloric acid ; but if a drop or two of chlorine-water is first added, barium sulphate is formed, which is insoluble in acids. The other precipitates are also soluble in acids. Tlie silver sulphite is decomposed on boiling, sulphuric acid being formed, and metallic silver set free.
To recognize the three radicals in an aqueous solution of sulphides, sulphites, and sulphates, add chloride of barium, filter, and wast the precipitate. I» tlie filtrate Bulnhides are detected hj the sulphu- retted hydrogen involved on adding an acid. In tho precipitate sulphites are detected by the odor of snlphnrons acid iirodnced on adding- Iivdrociibrtc add, and stdpbates by their insolubility in the
QUESTIONS AND EXERCISES,
492. What are the differences between sulphurous acid am phnroua acid gas, snlphites and acid sulphites 1
493. State the characters ofsulphnrons acid gas.
494. Uow is the official Sulphtirons Acid prepared ?
495. By what test may sulphurous acid be recognized in :
496. Oive a method by which sulphites may be detected ii aeiicc of sulphides and snlphates.
SULPHURIC ACID AND OTHER SULPHATES,
Foi-muk of SulplHU'ic Acid II.^SO,. Molecnlar weight 98.
Sulphates occur in nature; but the common and highly important hydrogen sulphate, sulphuric acid, is made artificially.
Pfeparalion of Sulphftric Acid. General nature of the process. — Sulphur itself, or sometimes the sulphur ia iron pyrites, ia first converted into sulphurous acid gas by burning in air, and this gas. by moisture and oxygen, into snlphnric acid (;HO,-t-U,0 + 0=n>OJ.
id .y Google
SULPHATES. 255
Details of the process.— Tlie oxjgeu necessary to oxidize the sul- phurous acid gaa uanuot diteetly bo obtained ft-oui air, but indirectly, the agency of nitric oxide (NO) being employcd^ — this gaa becoming nitric peroxide (NO,) by action of the air, and the uiti'ie peroxide again becoming nitric oxide by the action of the snlphnrous acid gas, and so 00, A small quantity of nitric oxide gas will in this way act as carrier of oxygen from the air to very large quantities of sulphur- ous acid. The nitric peroxide is in the first instance obtained from nitric acid, and this from nitrate of potassium or sodium by the action of a small quantity of the sulphuric acid of a previous operation.
Other processes. — Snlphnnc acid maybe obtained by other pro- cesses, as by distilling the sulphate of iron resulting from the natural oxidation of iron pyrites by air ; but it is seldom so made at the present day.
Ei^planation of the Commercial Process.— The following equa- tions represent various steps in the usual process ; —
2NaN0, + ILSO, = Na„SO, + 21IN0,
Kllrato jf Sulplinrio Sulptalo of Klliic
S^ + 20, = 2S0j
On the large scale the sulphurous acid gas is produced by bnrning inlphur in furnaces ; it is carried, together with the nitric vapors,
The resulting dilute sulphuric acid is couceutrated by evaporation in leaden vessels.
Experiment.— Toi purposes of pi-actical study, a small quantity may be made by passing, a. sulphurous acid gas (p. 2d2), b, nitric oxide fp. 237), e, air [forced through by aid of bellons or a gas- holder), and, occasionally, d, steam (generated in a Florence flnsk) through glass tubes, nearly to the bottom of a two- or tiiree-quart flask.
SO, + ILO = H„S0,; I 2X0 + O, = 2X0,; HjSOa +'XOj = n^HO, + XO.
A slow current of sulphurous acid gas, air, and steam, and n small quantify of nitric oxide, will fumiah, in the course of a few minutes,
id .y Google
25G SALTS or aoidvlous radicals.
enough Bulphurio acid for recognition by the first of the following analytical reactions.
Purificatiofi. ^Sulphuric a«id may contain araenie, nitrous com- pounds, and. salts. Arsenic may be detected by the hydrogen-test (p. 138), nitrous compounds by powdered sulphate of iron (ivhich ac- quires a violet tint if they are present), and salts by the residne left on boiling a little to dryness in a cmcible in a fame^^h amber. If only nitrous compounds are present, the acid may be purified by heating with about half per cent, of sulphate of ammonium — water and nitrogen being produced (Pelouze), If arsenic occurs, heat with a httle nitric acid, which converts arsenions (AsjO,) into arsenic an- hydride (Aa.Oj), then add snlphate of ammonium, and distil in a re- tort coutainmg pieces of quartz and healed by an annular-shaped burner (to prevent "bumping"). The arsenic anhydride remains in the retort. {Arsenions anhydride would be carried over with the sulphuric-acid vapors.l By distillation the acid is also purified from salts (ench as NaHSu,) which are not volatile-
Quantivalence. — The sulphuric radical being bivalent (SO/'), acid as well as normal sulphates may exist. Acid sulphate of potassium (KHSOj) is an illustration of the former, sulphate of sodium (Na^SOJ of the latter ; double sulphates may also occur, such as that of potas- sium and magnesium (K^Oj,MgSO„6HjO). Snlphates generally contain water of crvstallization.
Pure sulphuric add (HjSO,) is of specific ^vity 1.848. The best "oil of vitriol" of commerce, a colorless liquid of oily consis- tence, is of specific gravity 1.843, and contains 96.8 per cent, of real acid (HjSO^y. This is the Amdunt Sulphvricum.B. P. and U. S. P. The Acidum Sulphuricum Dilutum, B. P., sp. gr. 1.094 (U. S. P, 1,082) contains about ISJ (13.64) per cent, of acid {HiSOJ ; and the Acidum Sulphurtcwm Aromaticuin, B. B. and U. S. P., a dilute acid in which are dissolved the soluble aromatic parts of cinna- mon and ginger, also contains nearly 13J (13.36) per cent, of acid (HjSO,). There are some definite compounds of sulphuric acid with water ; the first (H^SO,, HjO) may be obtained in crystals.
Sulphuric anhydride (SO,) is a while silkj crystalline solid, having no acid properties. It is made by distilling sulphuric acid with phosphoric anhydride (3H^S0( -+- Ffi^ = 2H,P0. + 3S0,). It appears to unite with enlphuric acid and some otner normal sul- phates to form compounds (E^SOj, SOj) resembling in constitation red chnmiite of potassium or borax. The fuming sulphuric acid (n.S0„S03), made at Nordhausen in Saxony, seems to be such a body.
.iVoie.— Sulphuric acid is a most valuable compound to all chemists and manufacturers of chemical substances. It is the key by which hundreds of chemical salts are unlocked, and their contents utilized. To describe its nses would be to write a work on chemistry.
Analytical Reactions ( Tesl^).
First Analylicol Beaction. — To solution of a sulphate add solution of a barium salt ; a white precipitate of sul-
id.y Google
SULPHATES. 257
pliate of barium (BaSO,) falls. Add nitric acid and boil tlic mixture, the precipitate does not dissolve.
This reaction is as higlily characteristic of sulphates as it has been stated to be of barium salts (vide page T6). The only error likely to be made in its application is that of overlooking the fact that nitrate and chloride of barium are less soluble iu strong acid than in water. On adding the barinm salt to the acid liquid, therefore, a white precipitate may be obtained, which is simply the nitrate or chloride of barium. The appearance of such a precipitate ditFers considerably from that of the barium sulphate ; hence a careful ope- rator will not be misled. Should any doubt remain, water should be added, which will dissolve the nitrate or chloride, but not affect the sulphate.
Second Analyiical Reaclion. — Mix a fragment of an in- soluble sulphate (BaSO^e. (j.) with carbonate of potassium or of sodium; or, better, with both carbonates, and fuse the mixture 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 iDSolublo sulphates, such as those of barium and lead.
Third Analytical Reaction. — Mix a fragment of .an in- soluble sulphate with a little alkaline carbonate on a piece of charcoal, taking care that some of the charcoal-dtist is included in the mixture. Heat the little heap in the blow- pipe-flame until it fuses, and, when cold, add a drop of acid ; sulphuretted hydrogen is evolved, recognized by its odor.
This is another process for the recognition of insoluble sulphates. Other preparations of salphnr, and sulphur itself, give a similar re- sult. It is therefore rather a test for gnlphur and its compounds than sulphates only ; but the alisence of other salts can generally, if neces- sary, be previously determined.
jVb^e.— The presence of the SHlphuvic radicnl in a solution having been proved by the above reactions, its occurrence as the nomiai sui-
Shate of a metal is demonstrated by the neutral, or nearly neuti'al, eportuient of the liqnid with test-paper, and the detection of the metal — its occurrence as sulphuric acid or an acid sulphate by the sourness of the liquid to the taste, and the effervescence produced on the addition of a carbonate.
Antidote. — In cases of poisoning by strong sulphuric acid, solu- tion of carbonate of sodium {common washing-soda), magnesia and w.ifer, &c., mav be administfrpil :is antidotes.
id .y Google
ALTS OF ACIDULOUS RADICALS
QUESTIONS AND EXEECISKS.
49". What is the formula of sulphuric acid, and what its molecular weipht?
498. How is it related to other sulphates?
499. Write a short article on the manufacture of sulphuric acid, giving diagrams.
500. How may nitrous compounds be delected in, and eliminated Jrom, sulphuric acid?
501. State the method by which the presence of arsenic is detected in sulphuFic acid, and explain the process by vrhicb it may be re- moved.
502. Define salphates, acid sulphates, and double sulphates.
503. What percentage of real acid is contained in commercial oil of vitriol ?
504. State the strength of the official " diluted" and " aromatic" Bulphnric acid.
505. By what process is sulphuric anhydride obtained from Nord- hansen sulphuric acid?
506. Explain the reactions which occur in testing for sulphates.
507. Ascertain by calculation the weight of oil of vitriol (of 96.8 per cent.) necessary for the production of one ton ot dry sulphate of
noninm. — Ans. 1718 pounds.
J8. Name the antidotes in cases of poisoaing by strong sulphuric
CARBONIC ACID AND OTHER CARBONATES.
carbonic acid, CO,.
Sonrees. — Carbonates (compounds containing the firoupingCO^) are very common in nature, the calcium carbonate (CaCOj) being widely distributed as chalk, limestone, or marble. I'he hydrogen carbonate, true carbonic acid, is not known, unless, indeed, carbonic acid gas assumes that condition on dissolving in water {Aqva Acidi Garbonici, U. S. F.). Such a solution (see page 60) changes the color of blue litmus-paper, and the gas does not ; this may be because only the true acid (H„COj) afiecls tlio litmus, or because the gas (COji) cannot come into real contact with the litmus without a mednim. From the commonest natural carbonate, carbonate of cal- ciam, are derived the carbonic constituents ofthe one most frequently used ill medicine, carbonate of sodium.
Carbonate nf sodium is prepared from the chief natural salt, the chloride. After the chloride has been converted into sulphate (salt- cake) by sulphuric acid,
2XaC! + HjSO, 3= Na,SO, -f 2HC1, the sulphate is roasted n-ith limestone and small coal, by wliith car- bonate of sodium and an oxysulphide of calcium are fni'iiud : —
:r.NaX'0,4 r,t'u8, 'jei.o+'.;oro-i--ji;o..
id .y Google
CAGEONATES 259
Carbonic oxide gas and some carbonic acid gas escape; Uic residual mass (black ash) is digested ia water, in which the carbonate of sodium dissolves, the double oxide and sulphide of calcium remaining insoluble. The solution is evaporated to dryness, and yields crude carbonate of sodium. This is roasted with a small quantity of saw- dust, to convert any caustic soda into carbonate. The product is sodd'Osh. Dissolved in water and crystallized, it constitntes the ordinary "soda" used for washing purposes : recrystallizcd and some- times ground, it forms the official carbonate of sodium {Sod<s Car- boims. B. P. and U. S. P.) {Na^CO,, 10H,O). The reaction is rendered more intelligible by regarding it as oeeurrtng in three stages : Ist, the reduction of the sulphate of sodium to sulphide by 'the carbon of the coal,
Na,80, + C. = NsjS + 4C0; 2d, the rea<;tion of the sulphide of sodium and carbonate of calcium, giving soluble carbonate of sodium, thus— ■
Na,S + OaCOs = Na.COj + CaS : and, 3d, the combination of sulphide of calcium with lime from the chalk, giving insoluble oxysuiphide of calcium — 6CaS + aCaCOj = 5CaS, 2CaO + 2C0j. Carbonic acid gas (GO,) is a product of the combustion of nil carbonaceous matters. It is constantly exhaled by animals and inhaled by plants, its intermediate storehouse being the atmosphere, throughout which it is eqaalty distributed by diffusion (vide p. 21) to the extent of abont 4 parts in 10,000. A. larger pror«rtioii than that just mentioned gives to confined air depressing effects, 4 or 5 per cent, rendering the atmospliere poisonous when taken into the blood from the lungs. Carbonic acid, however, may be taken into the stomach with beneficial sedative effects; hence, probably, much of the value of snch effervescing liquids afi soda-water, leinonade, and solntions of the various grannlatea preparations and effervescing powders (vide p. 62). The gas liquefies on being com pressed, anil the liquid solidifies on being cooled. Carbonic acid gas is twenty-two times as heavy as hydrogen.
Reactions.
Synthetical and Analytical Bcaetions. — 1. To a fragmoiit of marble in a test-tube add water and then hydrochloric acid; ■eai'bonic acid gas (COJ is evolved, and may be con- veyed into water or soUitiona of salts by the usual delivery- tube.
This is the process of the British Pharmacopo;ia, nnd the one usually adopted for experimental purposes. Passed into enrboniite of sodium, tne gas gives Sdrfte^iVarSonas (p. 47), and into carboniitc of potassium, Potassce Bicarbonas (p. 58). On the large scale llie gas is prepared from chalk and sulphuric acid, frcquctit stirring pro- moting its escape.
id .y Google
2C0 SALTS OF ACIDULOUS RADICALS,
2. Pass the gas into lime-water; a white precipitate of cavbonate of calcium (CaCO,) falls. Solution of siibacctatc of lead may be used instead of, and is perhaps even a more delicate test than, lime-water.
The evolution of a gas on adding on acid to a salt, warrniug tlie mixture if necessary, the gas being inodoroas and giving a white precipitate with lime-water, is snfiicieut evidence of the iii-esenee of a cnrbouale. Carbonates in soKition of ammonia, potash, or soda, may be detected by the direct addition of solntiou of lime.
3. Blow air from the lungs through a glass tube into, lime-water; the presence of carbonic acid gas is at once indicated.
The passage of a considerable quantity of normal air tliroug-h lime-water produces a similar effect. A bottle coiitainiiifr lime-water eoou becomes coated with carbonate of calcium from absorption of carbonic acid gas.
i. Fill a dry test-tube with the gas, by passing the delivery-tube of the above api)aratus to the bottom of the test-tube. Being rather more than once and a half as heavj' as the air (1.529), it will displace the latter. Prove the presence of the gas tiy pouring it slowly, as if a visible liqnid, into another test-tnbe containing lime-water; the characteristic cloudiness and precipitate are obtained on gently shaking the lime-water.
In testing for carbonates by bringing evolved gas into contact with lime-water, the preparation and adaptation of a del i very-tube niiiy often be avoided by pouring the gas from the generating'-tabc into that containing the lime-water in the manner just indicated.
5. Pass carbonic acid gas through lime-water nntil the precipitate at first formed is dissolved. The resulting liquid IS 1 solution of c^ibonatc ot cikium m caibonic aciil water Boil the solution caibonn, atid gas (.seaijea, and the ciiboiiate is agam piocipitatcd
Hus experiment mil er^c to ihow how ehdl I , i n u
in oidiniuj well waters gi\nig the propeitv ol I i i
the/Hi or stone like deposit in teakettles and I i li
houldl liu. tjf.dtint ulpliiti, .U.I.ium |i I
suit ill! il il t[ I li (1 il li I ,! I
id .y Google
QUESTIONS AND EXERCISES.
SOS. Name the chief natural oarbonates.
510. What are the formaliE of cai'boiiic acid aud taibouic acid gaal all. Adduce evidence of the existence of true carbonic acid.
512. Trace the steps by which the carbonic constituents of chalk are transferred to sodium by the process usually adopted in alkaii- wovks — the manufacture of "eoda."
513. Carbonic acid gas is constantly exhaled from the lungs of animals ; why does it not accumulate in the atmosphere ?
514. What is the effect of pressnre on carbonic acid gas !
515. State the speciBc gravity of carbonic acid gas.
516. By what processes may carbonic acid gas be obtained for os- pcrimental and manufacturing-purposes !
517. Describe the action of carbonic acid gas on the carbonates of potassium or sodium.
518. How may carbonic acid be detected in expired air t
519. To what extent is carbonic a«id gas heavier than air ?
520. What quantity of chalk (90 per cent, pure) will be required to furnish the carbonate acid necessary to convert one ton of car- bonate of potassium (containing 83 per cent, of K,CO;,) into acid carbonate, supposing no gas to be wasted ! — Ans. 1500 lbs.
521. Define " hardness" in water.
522. How may the presence of carbonates be demons (rated ?
OXALIC ACID AHD OTHER OXALATES.
Formula of O.-ialic Acid n^C,Oj,2H50. Molecular weight 126.
Sources. — Oxalates occur in natnrc in the juices of some plants. B9 wood-sorrel, rhnbarb, the common dock, and certain lichens ; but the hydrogen oxalate (oxalic acid) and other oxalates are all made HrtificioUy. Many organic substances yield oxalic acid when boiled with nitric acid, aud an alltaline oxalate when roasted with a mixture of the hydrates of potassium and sodium.
Experimental process. — On the small scale, a mixture of nitric acid and loaf sugar yields the acid in the purest form, the two being boiled together for some time.
Manufacturing process. — On the large scale, sawdust is roasted with alkalies, resulting oxalate of sodiam decomposed by lime with formation of oxalate of calcium, the latter digested with sulphuric acid, and the liberated oxalic acid (Osalic Acid of Commerce, B. F.) purified by recrystaHization (Oxalic Acid, Purified, B. P.).
Quanttvcdence. — The elements represented by the formula C.^O, are those characteristic of oxalates. They form a bivalent group- ing; hence normal oxalates (E'jCjO^), and acid oxalates (R'llOjO,)
Salt of sorrel is a crystalline compound of oxalic acid with acid potassium oxalate (KHOjO.,H;C;0,) the crystals containing two molecules of water of crystal IIzll lion.
id .y Google
2G:i SALTS OF ACIDULOUS RADICALS.
Anahjtical Heaeltons (Teds).
First Anahjtical lleavtion. — To solution of an oxalate (oxalate of aminoniiiin e. g.) add solution of chloride of calcium ; a white precipitate falls. Add to the precipitate excess of acetic acid ; it is insoluhle. Add hydrochloric acid ; the precipitate is dissolved.
The formation of o. white precipitate on adding a, calcium or Itarium salt, insoluble in acetic bnt soluble in hydrooWoric or nitric aciil, is nsually sufficient proof of the presence of an oxalate. 'I'he action of the liijuid on litmus paper, effcrvosccnce with carbonate of soilioni, and absence of metals, would indicate that the oxalate is that of hydrogen, o-xatic acid.
Antidote. — -In cases of poisoning by oxalic ocid or salt of sorrel, chalk and water may be administerecf as a chemical antidote (with the view of producing the insoluble oxalate of calcium), emetics and the stomach-pump being used as soon as possible.
Second Analytical Reaction. — Heat a fragment of a fixed metallic oxalate (an oxalate of potassium for example) in a test-tnbe; decomposition occurs, carbonic oxide (CO) (a gas that will be noticed subsequently) is liberated, and a carbonate of the metal remains. Add water and then an acid to the residue ; effervescence occurs.
This is a ready teat for insoluble oxalates, and is trustworthy if, on heating the substauee, no charring occurs. Organic salts of metals decompose when heated, and leave a residue of carbonate, but exeept in the ease of oxalate, the residue is always accompanied by much charcoal.
Other Analytical Beactions. — Nitrate of silver gives,
with oxalates, white oxalate of silver (Ag,CjO^). Dry
oxalates are decomposed when heated with strong sul- phnric acid, carbonic oxide, and carbonic acid gases escai> ing. If much of the substance be operated on, the gas may be washed with an alkali, the carbonic acid be thus removed, and the carbonic oxide be ignited; it will be found to burn with a characteristic bluish flanae. Oxa- lates, when mixed with water, black oxide of manganese (free from carbonates), and sulphuric acid, yield carbonic acid gas, which mjiy be tested by lime-water in the usual
manner. Insoluble oxalates, such as those of calcium
and magnesium, may be decomposed by cbnllition with soltttion of carbonate of sodium ; after filtration the oxalic radical will be found in the clear liquid as soluble oxalate of sodium.
Test of PiH-jVu.—" Purified oxalic iicid . . . . i.5 entirely dii?si- pated by a heat below SoQO F." (B. F.)
id .y Google
TARTRATES.
QUESTIONS AND EXERCrSEH.
523, Explnin the constitution of oxalates.
5"24. State how oxalates are obtained.
525. Whut is the quant ivaloiico of the oxalic radical ?
ri2e. Give the formula of " salt of sorrel."
527. Steution the chief test for oxalic acid and other soluble o,\ulates.
528. Name the antidote for oxalic acid, and describe its action.
529. Bj- what reactions are insoluble oxalates recognized ?
TARTARIC ACID AND OTHER TARTRATES.
Fonnuk of Tartaric Acid H/1.11,0„, or II/F. Molecular weight 150.
.S'o Hires.— Tartrates exist in the juice of many fruits; but it is from that of the grape that our supplies are nsually obtained. Urape-juice contains much acid tartrate of potassium, which is gradu- ally deposited when the juice is fennented, as in making wine ; for acid tartrate of potassium, not very soluble in aqueous liquids, is still less so in spiritoons, and heuce crystallizes out as the sugar of the grape-juice is grudaally converted into alcohol. It is found with tartrate of calcium lining the vessels in which wine is kept; aai it is from this crude tartar* (argal or argol), as well as from what tartar may be remaining in the marc left after the juice has been pressed from the grapes, that tartaric acid and other tartrates are prepared.
Cream of tartar, purified by crystallizatioD (Potassm Tartraa Aeida, B. P., Potassa Bitartroi, U. S. P.), occurs as a " grilty white powder, or fragmenta of cakes crystallized on one surface ;" of a pleasant acid taste, soluble in 180 parts of cold and C of boiling water, insoluble in spirit.
QuantivQience.~li:h.% elements represented by the formula OjlIjOj
e those characteristic of tartrates. They form a bivalent grouping ;
hence normal tartrates (E',T) and acid tartrates (E'HT) exist. Tartrate of potassium, the Potass<s Tartraa of the IT. 8. Pharma- :opo3ia (KjC,H.O„) and Koehelle Salt, or tartrate of pota?
and sodium [KkaO.H^Os, 4HjO), the official Potasste et Sodcv Tartras {Soda Tarlarata, B. P.), are illustrations of normal tar- ates, whde Urcain of Tartar is an example of acid tartrates. The
* "It is called tartiir," says Patacelsiis, "because it produce,'! oil, water, tincture and sail, wliioli burn the patient as tarUiua does." Tartaraa WL&Mn (Tap-npac, Tat t area, Grmik) for hell. The produots of its destracUve distillation are certainly somewhat irritatiug In taste and smell; and the "salt" (oarbonate of potassium) that ia left is diuretic, and, in larger quantlllea, powerfully corrosive.
.\ boilinp; solntioii of lart»r yields a floating ctasi of minute crya-
id, Google
2G4 SALTS or ACIDULOUS RADICALS,
only official tartrate not apparently included in these gencrol for- malie is tartar-emetic LAnltmuni-am Tarlaral«m,B.F., Antimoiiii et Potassce Tartraa, TI. 8. P.), which is sometimes regarded as the double tartrate of potassium and a hypothetical radical, antimony! (SbO), thus, KSbOCjHjOs. Possibly, however, it is but an oxytur- trate of antimony {Sb^OgT) with normal tartrate of potassium (K,'L') ; for there are several oxvcomponnds of antimony analogous to the ozycompounds of biBmnth that have been described (p. 207), normal salts partially decomposed by water into oxides, and many of these osycomponnds readily unite with normal salts of other basylous radicals. Tiirtar emetAC would thus be oxylartrate of antimony with tartrate of potassium (Sb^O J, K^T, or Sb^OiC^H^O^, K,(J,H,OJ.
Tartaric Acid.
Tarlartc Acid {Acuhim Tariarieum, B. P. and U. S. P.) is obtained, according to the British Pharraacopecia, by boiling' cream of tartar [Potaasoi Tartras Acida, B, P., Fotassce Bitarti-as, U. S, P. ] witn water, adding chalk till effervescence ceases, and then chloride of calcium so long as a precipitate foils ; the two portions of tartrate of calcium thus consecutively formed are thoronehly washed, treated with snlpliurie aeid, the mixture boiled for a Buort time, resulting sulphate of colcium mostly separated by filtration, the filtrate concentrated by evaporation, ony sulphate of calcium that may have deposited removed as before, ana concentration continued until the solution is strong enough to crystallize. Tartrate of cal- cium from 9 ounces of cream of tartar requires 5 ounces by weight of sulphuric acid for complete decomposition. 2KHT + CaCOj = CaT + K,T + H,0 + CO,
Tartaric acid occurs in colorless crystals, or the same powdered. It ia strongly acid and readily soluble in water or spirit. One part in 8 of l^'ate^ and 2 of spirit of wine forms " Solution of Tartaric Acid," It. P. Its aqueous solution is not stable.
Tartrate of Potassium.
Synihelico! Heaclions. — To a small quantity of a strong
solution of carbonate of potassium atM acid tartrate of
potassium ao long as effervescence occurs ; the resulting
liquid is sohitiou of normal tartrate of potassinni (Fulasuse
id .y Google
TARTRATE
Tarlras, B. P. and TJ. S. P.) (K^T), crystals of which may be obtained on evaporation.
Note. — This is a common method of conTertvng ao acid salt of a bivalent acidulous radical into a norma! salt. The carbonate added iioed not be a carbonate of the same, but may be of a diftfrent metal; compounds like Rochelle salt (KNaT) are then obtained. Thus ;—
Tartrate of Potassium and Sodium. To a strong hot solution of carbonate of sodium arid acid tartrate of potassium until effervescence ceases ; the resulting liquid is solution of tartrate of potassium and sodium : on cooling, it yields crystals. This is the official process {Soda Tarlarata, B. P., Fotassee el Sodse Tartras, U. S. P.) (K.NaT,4H,0).
Equivalent We«htB 0/ Tartaric Acid, Oarionate of Potassium, Biearbonate i^ Potassium, Carbonate of Sodium, Bicarbonate of Soditim, and Carbonates of Ammoniam and Magnesium : repeated for 2Q parts of each (and, incideataHy, for other propor- tions).
|
Tart. Ada . . .. |
H^.HA |
= 150 30 |
.=..!.. |
im'm |
asj |
31i |
|
Csrb PoUs |
K.COa (of 93 per |
™i.)... = 165 23 |
20 1 161 |
llii HI |
341 |
|
|
BMrb Pot |
!KKHCOJ |
= a»,36! |
21*30 |
34 |
||
|
Carb SodafciTtt |
Ka.CO^lOn.O |
= 286.88 |
3U asi |
ao 34 |
||
|
Bicarb S d |
aitiiHCOJ |
=168 asi |
20i|l6i |
iiiao |
2S) |
aij |
|
Catb Affimon |
(M H fiJ3, +" |
-nsl6i |
1411 Hi |
SJ u |
no |
241 |
|
Cirb MjjueB |
(MgCOj) Mg°HO 4 |
IT.-HM = M.5 lat |
lUj fli |
6*1 Hi |
IB |
ao |
Thus 20 parts (grains or other weights) of tartaric acid neutralize 22 of carbonate of pottssiom, 26J of bicarbonate of potassium, 38 of carbinate of sodium 22^ of biearbouate of sodium, 15J of car- bonate of ammonium or li| of carbonate of magnesium. Other quantities of tirtarn, ucid (18^, 15, lOi, ITJ, 2oJ, 31J) satarate the amouuts of salts mentioned in the other columns and vice versa. A 'Similar Table for Citwc Acid will be found at page 269, and for both acids in the Appeiidix. These Tables afford good illastra- tions of the laws of chemical combination (page 36). The reader
tht salts formed are considered to be neutral in constitution. In medical practice effervescing saline draughts are often designedly prescribed to contain an amount of acid or alkali considerably in exiicjss of the proportions required for perfect neutrality. A ceninion form of SeitUits Potoder cousists of 3 parts of Kucheile 23
id .y Google
266 SALTS or ACIDULOUS RADICALS.
salt (120 grains) with 1 (40 grains) of acid carbonate of sodium (the mixture usually wrapped iu blue paper), an<l 1 (40 grains) of tartaric aeid (wrapped in white paper). When administered, the latter is dissolved iu a tumbler rather more than half full of water, the former added, and the mixture drank during effervescence. It will be seen that the salts swallowed are tartrate of potassium and sodiuni (KNaT,4HjO), tartrate of sodium (Na,fi2H;0), and acid tartrate of sodium (NajHI'.HjO). The last-mentioned salt results because !!{ percent. (4^ grainsji of the tartaric acid is in excess of the quantity necessary for the formation of neutral tartrate of sodium. This amount of acid salt gives agreeable acidity to the draught. The United States formula (/^i/feres Efm-vescetUes Apeneiites, U.S.P.) includes rather less tartaric acid, so that only neutral salts arc formed.
Analytical Beactions {Tests).
First Analytical Eeaction. — To solution of any normal tartrate, or tartaric acid made neutral by solution of soda, add solution of chloride of calcium; a white precipitate, tartrate of calcium, falls. Collect the precipitate on a Alter, wash, place a small quantity in a test-tube, and add solution of potash ; on stirring the mixture the precipitate dissolves. Heat the solution ; the tartrate of calcium is again precipitated.
The solubility of tartrate of calcium in coid potash solution ena- bles tlie analyst to distinguish between tartrates and citrates, other- wise a difficult matter. Citrate of calcium is not soluble in the alliali. The absence of much animoniacal salt must be insured iu both cases, the precipitates being soluble in such liquids.
Second Analytical Beaction. — Acidulate a solution of a tartrate with acetic acid, add acetate of potassium, and well stir the mixture ; a crystalline precipitate of acid tar- trate of potassium slowly separates, Tbe precipitate being insoluble in alcohol, the addition of a little spirit of wine renders the test more delicate.
This reaction is not applicable in testing for very small quantities of tartrates, the acid tartrate of potassium being not altogether iiisolui)le.
Third Avalylical Reaction. — To a neutral solution of a tartrate add solution of nitrate of silver ; a white precipi- tate of tartrate of silver, Ag,C,H,0„, falls. Doil the mix- ture ; it turns black, owing to the reduction of the salt to metallic silver.
Other Si'aclions. — Tartrates heated with strong sulphu- ric acid char immediately , Tartaric acid and tlic soluble
id .y Google
CITBATES. 2G7
tartrates prevent tlie pvecipitation of ferric and other hy- drates by alkalies, eohihle double tartrates being formed (which on evaporation yield liqliids that do not crystallize, but, spread on sheets of glass, dry up to thin transparent plates or scales). The ferri et potassie tavtras, V. S. P. {Ferrum TarlaraUttn, B. P.), ia a preparation of this kind.
Tartrates decompose when heated, carbonates being
formed and carbon set free, the gaseous products liavinga peculiar, more or less characteristic smell, resembling that of burnt sugar.
QUKSTI0X3 AND EXERCISES.
5.10. State tiic origin of tartaric acid hikI otlier tavfralcs. aiul ex- plain tlie deposition of argol, crudi! acid tartrate of potassium, during the manufacture of wine.
531. "What are the chemical formula and characters of " cream of tartar f"
532. Mention the formula and qnantivalence of the tartaric radical.
533. Write formal^ of normal, acid, and double tartrates, tartar- emetic being treated as an osytartrate of antimony ivith tartrate of
334. Give equations or diagrams illustrative of the production of tartaric acid ftim cream of tartar.
535. By what general process may normal or double tartrates be obtained from acid tartrate of potassium ?
536. Work out sums proving the correctness of some of the fiijures given on p. 265 as showing the satnrating-powcr of tartaric acid for various qnautities of different carbonates, and give diagrams or equations of the reactions.
537. State the names and quantities of the salts resulting from the admixture of 120 grains of tartrate of potassium and sodiam, 40 grains of acid carbonate of sodium, and 40 graius of tartaric acid (SeidiitK powder).
5:18. Enumerate the tests for tartrates, and explain the effects of heat un tartrates of the mctuls.
CITRIC ACID AND OTHER CITRATES.
Formula of Citric Acid H,C,H;0;, H,0 or H.CiAq. Molecular weight 210.
Source. — Citric acid {Aciduin Citrieiim, B. P. and TJ. S. P.) ex- ists in (he juice of many of oar common garden fruits ; tbns (he j>ulp of the fruit of Tamariiidus inilka {Ta.marindus. B. P. and U. S. P.) contains nearly 10 per cent, (in addition to 1.5 of tartaric acid, .5
id .y Google
2R8 SALTS 0¥ ACIDULOUS RADICALS,
of malic acid, and 3 per cent, of acid tartrate of potassium). But it is from the lemon or lime that the acid of commerce is usually ob- tained.
Pfoeess.— The British Pharmacopteia directs that the hot lemon- juice (4 pints) be saturated by powdered chalk (4J ounces), the resulting citrate of calcium collected on a filter, washed with hot wat«r tul the liquor passes from it colorless, then mixed with cold water (1 pint), decomposed bj[ sulphuric acid (2^- fluidounces in IJ pint of water), the mixture boiled for half an hour, filtered, the solu- tion evaporated to a density of 1.21, set aside for 24 hours, then poured off from any deposit of crystalline sulphate of calcium, fur- ther concentrated and set aside to crystallize.
2H,0,H:,0, + aCaCOs = Ca32C.H50, + 3H,0 + 300^
Ca320,H-0, + 3H,S0, = 2H,C„H,0- + 3CaS0.
CLIriHe of Sulplinrio Ciiric acid Sulpliale at
CHlciuio. add. If are). calcium.
Quattftvalence.—Tlie elements represented by the formula CjHj^O, are those characteristic of citrates. They form a trivatont grouping ; hence three classes of salts may exist — one, two, or three atoms of the basylous hydrogen in the acid, HjCjH^O,, being displaced by eqnivalent proportions of other bafiylous radicals.
Citric acid itself is the only citric compound of much direct im- portance to the pharmacist. It usually occurs in colorless crystals soluble in half their weight of boiling and three-fourths of cold water, less soluble in spirit, and insoluble in ether. A solution of about 34 grains in 1 ounce of water forms a sort of artificial lemon- juice. Citrates heated with strong sulphuric acid to about 212° p. evolve carbonic oxide gas, and at higher temperatures acetone and carbonic acid ^as.
"Effervescing Citrate of Magnesia," so-called, is generally a mixture of bicarbonate of sodium, citric acid, tartaric acid, sugar, either carbonate or sulphate of magnesium (sometimes neither) and occasionally essence of lemon. Trae citrate of magnesium is easily made by heating together calcined magnesia and citric acid; it is frequently prescribed in France in doses of two ounces. Liquor Magnesia Cttratis, U. S. P., is a bottled mixture of magnesia, citric acid, and syrup, with bicarbonate of potassiam, and sufficient water to nearly Ml the bottle which is closed by a cork secured with twine.
The qffict'al Lemon Juice (Skccms Limoitum. B. P., lAmonia Succus, v. S. P.) is to be freshly expressed from the ripe fruit, and contain an a,verage of 32.5 grains of citric acid in 1 flaidounce. The acidity may be ascertained by adding solution of potash or soda (the strength of which has been previously determined with pure crystals of citric acid) till red litmus paper is fairly turned blue. Before applying this test to commercial specimens, the absence of notable quantities of sulphuric, hydrochloric, aoetic, tartaric, or other acid must be insured by application of appropriate reagents.
Mistura Potassce CitraUa, U. S. P., is lemon juice completely neutralized by bicarbonate of jwtassium. It is a slightly impure but flavored solution of citrate of potassium.
id, Google
Equivalent Weights f>f Citric Acid, Carbonate nf Potasshtm, Bivarbtmatc o/Putassinra, Carbtmate of Sodium, Bicarbonate of Sodium, and Carbonates of Ammonium and Miigntsium ; repealed for 20 parte of each (and, incidentally, for other propor-
Carb. P< Bicarb. : Curb. Sod, (erysl,)
H,C,H,0„H,0
(K,COj:otS3p.ct.l+2X3 = 2W 23t
3(KHC0,) =300 281
lNo,COj,lDn,0)--2X3,..=429 40}
20 Il7 14 8i I6i 3 30 I IB) ml l»j
(SfiJ^M+iXS = 177 il6i
(MgCO,),MsaHO, iH.O) I
-^SX3 = 1M1 13i
2Di lej 111 20
SO 21}
Thus 20 parts (^ains, or other weights) of citric acid iiciitriilizo 23| ot carbonate of potaasinm, 28 J of liicarbonate of potassium, 4UJ of carbonate of sodium, 24 of bicarbonate of sodium, ItiJ of earbim- ate of ammonium, or 13^ of carb. of magnesium. Other quaiititii?s of acid (17, 14, 9J, 16J. 23|, 2H) satnrate the amounts of salts meu- tioned in the other colnmna, and vice versa.
This Table, the similar one for tartaric acid (p. 265), and that for both acids {vide Appendix) afford good illuslrations of some of the laws of chemical combination (p. 36). 'ITie reader should verify a few of the numbers by calculation from the atomic weights of the elements concerned in the reactions, remembering that the salts formed are considered to be neutral in constitution. In medical practice, effervescing saline draughts are often designedly proseribinl to contain an amount of acid or alkali considerably in excess of the proportions required for perfect neutrality.
Analytical Eeaclion^ (Tests).
First Anahjlical Reaction. — To a dilute solution of any neutral citrate, or citric acid carefully neutralized by alkali, add solution of chloride of calchim and boil ; a white pre- cipitate, citrate of calcium (CajCiJ, falls. Treat the |3re- eipitate as for tartrate of calcium (p. 266); it is ho( dissolved by the potash.
A mixture of citrates and tartrates can be separated liy this reac- tion. They are precipitated as calcium sails, aud the washed pre- cipitate raised with solution of potash, diluted and filtered ; the fil- trate contains the tartrate, which is shown to be present by reprecip- itation on boiling. The precipitate still on the flller is washed, dLS- solved in solution of chloride of ammonium, and the solution boiled; the citrate of calcium is reprecipitated. The presence of much sugar interferes with this reaction. A dilute solution of a citrate is 23*
id .y Google
SALTS OF ACIDULOUS
not preciijitated by chloride of calcium until the liquii! is heated : precipitation from a strong solution, also, is not thoroug-hly complete without ebullition of the n'^'- -
Second Analytical Reaction. — To a neutral solution of a citrate add solution of nitrate of silver; a white precipi- tate of citrate of silver (Ag^Ci) falls. Boil tlie mixture; the precipitate does not turn black as tartrate of silver does.
Other Analytical EeacHons. — Citric acid forms no pre- cipitate correB ponding with the acid tartrate of potassium.
Lime-water, in excess, gives no precipitate with citric
acid or citrates, unless the solution is boiled, citrate of calcium being si ightlj' soluble iu cold but not in hot water;
it usually precipitates tartrates in the cold. Citrates,
when heated with strong sulphuric acid, do not cbar imme- diately. Citric acid and citrates prevent the precipita- tion of oxide of iron by alkalies, soluble double compounds being formed. The Ferri et Ammoniee Citras, B. P. and
17. S. P., is a preparation of tliis kind. Metal! tc citrates
decompose when heated, carbonates being formed and car- bon set free: the odor of the gaseous products is not so characteristic as tliat of tartrates.
QUEBTIONS AND EXEltiJISES.
539. What is the source of citric acid?
540. Describe the method by which citric acid is prepared, giving
541. Illustrate by fonnulte the various classes of tartrates and citrates.
542. State the average proportion of citric acid iu lemon-juice.
543. Work out the sums proving the eorrectiieea of some of the figures given on page 269 as showing the sat u rating-power of citric acid for various carbonates.
544. What are the tests for citrates ?
545. How are the tartrates separated from citrates ?
PHOSPHOEIC AGID AND OTHER PHOSPHATES.
Formula of Phosphoric Acid HjPO,. Molecular weight 98,
Source.- — The source of the ordinary normal phosphates and of phosphorus itself [Phosphoius. B, P, and U. S, P,) is the normal phosphate of culcium (Ca,2rOJ. It is the thief constituent of (he
id .y Google
PHOSPHATES. 271
bones of animals, being derived from the plants on whict thej feed, plants again obtaining it from the soil.
Process. — Phospliorus is obtained from bones by the following processes : The bones are bnrnt to remove ail traces of animal matter. The resulting bone-earth is treated with sulphnrie acid, by which an acid phosphate (CaH,2P0j), often called superphosj>hate of lime, is produced : —
Ca32PO< + 2Hj80, = CaH,2P0j + 20aS0^.
The aeid phosphate is mixed with charcoal and strongly heated in a retort, when it splits np into normal phosphate of calcinm and phosphoric acid—
3CaH.2PO, = Caa2P0. + 4H,F0„ the phosphoric acid being reduced by the charcoal to phosphorus and hydrogen, and carbonic oxide gas liberated : —
HjPO, + C, = P + H, + 400.
Phosphorus is "a semitransparent, colorless, wax-lifce solid, which emits wlute vapors when exposed to the air. Specific gravity LIT. It is soft and flexible at common temperatures, melts at lltF, ignites itt the air at a temperature a little above its melting-point, burning with a luminous flame and producing dense white fumes. Insoluble in water, but soluble in ether and in boiling oil of turpentine," also in bisulphide of carbon.
Qiiantwalence. — The atom of phosphorus is quinquivalent, as seen in the pentachloride (PCI5) and psyehJoride (PCI,0), but it often exhibits trivalent activity as seen in the trichloride and trihy-
Phosphoiie Acid.
The chief use of phosphorus in pharmacy is in the for- mation of Diluted Phosphoric Acid. Phosphorus is boiled ■with nitric acid and water until dissolved. The solution, evaporated to a low bulk to remove nitrous compounds, and rediluted so as to contain nearly U (13.8) per cent, of acid (HaPOj), equivalent to 10 per cent, of phosphoric an- hydride (P5O5), constitutes the Acidum, Phosphoricum Di' lutum, B. P. and TJ. S. P., a colorless sour liquid of specific gravity 1.08 (1.056 IT. S. P.). If the necessary appliances are at hand, four or five ounces of this acid may be pre- pared as follows : A quarter of a pint is made by boiling together, in a retort attached to a Liebig's condenser, 103 grains of phosphorus, 1^ fluidounce of the official nitric acid, and 3 ounces of water. When about 1 oz. of water has distilled over it should be returned to the retort, and the operation repeated , until the phosphorus has disap- peared.
id .y Google
2T3 SALTS OF ACIDULOUS EADICALS.
P, + lOHNO, + 4H,0 = 6II,P0^ -j- lONO
The liquid remaining in the retort is then transferred to a dish (preferably of platinum), evaporated down to about half an ounce, and, lastly, diluted with distilled water to 5 fluidounccs.
The use of the water in this process is to moderate the reactioo. Strong hot nitric acid oxidizes phoaphorns with almost explosive rapidity, hence most not only be dilated in the flret instance, but he rediluted, from time to time, to prevent its becoming too strong by loss of water. Deficiency of nitric acid must also be avoided, or some phoaphotoua acid (HjPHOj) will be formed. A flask, in the neck 01 which a funnel is inserted, and a second funnel inverted, so that its mouth rests within the mouth of the first, is an efficient and convenient arrangement of apparatus for this process, especially if the operation be conducted slowly.
Solution of phosphoric acid evaporated leaves a residue which melts at a low red heat, yielding pyropfiospAoivc acid, and, finally, metaphosphoric acid [Glacial PJwsphortc Acid).
Qi(an(*«iaJence.— The elements represented by the formula POj are those characteristic of phosphates. The grouping is trivalent; hence there may exist trimetallic or normal phosphate (M'jPO,), dimetallic acid phosphates (M'^PO,), monometallic acid phos- phates (M'HjPO,), and, lastly, trihydric phosphate (H^POJ, or common phosphoric acid. These are the ordinary phosphates met with in nature or used in pharmacy ; the rarer pyrophosphates, metaphoBphates, phosphites, and hypophosphites will be mentioned subsequently.
Analytical Beactions (Tests').
First Analytical Seaction. — To an aqueous solution of a phosphate (e.g. Na^HPOJ add solution of sulphate of mag- nesium with which chloride of ammonium and ammonia have been mixed ; a white crystalline precipitate of ammo- nio-magnesium phosphate falls (MgAmPOJ.
Chloride of ammonium is added to prevent the precipitation of hydrate of magnesium. Arseniates, from their close analogy to phosphates, give a similar precipitate with the magnesium reagent.
Second Analytical Seaction. — To an aqueous solution of a phosphate add solution of nitrate of silver; light-yellow phosphate of silver (AgjPO,) is precipitated. To a por- tion of the precipitate add ammonia ; it dissolves. To another portion add nitric acid ; it dissolves.
By this reaction phosphates may be distinguished from their close allies the arseniates, arseniate of silver being of a chocolate color.
id .y Google
PHOSPHATES. 213
Third Analytical Reaction. — To a solution (in a few (Iropa of acid) of a phosphate insoluble in water {e.g. Ca,2POj) add an alkaline acetate (that ia, a mixture of soda or ammonia with excess of acetic acid), and then a drop or two of solution of perchloride of iron; yellowish- white ferric phosphate (Fe„POJ is precipitated.
Too mncli of the ferric chloride must not be added, or ferric acetate will be produced, in which ferric phosphate ia to some extent sol able.
To remove the whole of the phosphoric radical from the solution, add ferric chloride so long as a precipitate is pro- duced, and then boil the mixture; ferric phosphate and ferric osyacetate are precipitated.
To obtain confirmatory evidence of the presence of phos- phate in this precipitate, and to separate the phosphoric radical as a pure unmixed phosphate, collect the precipi- tate on a filter, wash, drop some solution of ammonia on it, then eulphydrate of ammonium, and finally wash with water ; blacli: ferrous sulphide remains on the filter, while phosphate of ammonium occurs in the filtrate. To the fil- trate add a mixture of solutions of sulphate of magne- sium and chloride of ammonium, and well stir ; ammonio- magnesian phosphate is precipitated.
The above reaction is nseful in the analysis of bone-earth, other earthy phosphates, phosphate of iron, and all phosphates insoluble in water. Only araeniatea giTe similar appearance; but the acid solution of these may be decomposed by suiphnretted hydrogen (H.S), especially after agitation with snlphnrons acid and subaequent ebul-
Olher Analytical Reactions. — Solutions of barium and calcium salts give, with aqueous solutions of phosphates, white precipitates of the respective phosphates BaHPO^, or Ba,2P0„ and CaHPO„ or C&fi'PO,, all of which are soluble in acetic and the stronger acids.
Vanadium^ V. 51.3, is a very rare element, and is here men- tioned only because of its exceedingly interesting relation- ship to nitrogen, phosphorus, and arsenicum. Discovered but not isolated by Sefstrom, and its compounds investi- gated by Berzelius, it has only recently been obtained in the free state and fully studied by Roscoe. N,0„ N^O,, N,0„ N,0.,, N3O. V,0,, V,0„ V^O^, V,0„ V,0
id .y Google
2Ti SALTS OF ACIDl
Oxides of Nitrogen. Orthophosphates K^'PO^ Pyrophosphates R/P^O, Metaphosphatea E.'POj
Isomorplious Minerals. Apatite 3(Ca,2PO,),CaFI,
Pyromorphite 3(Pb,2PO ),PbCl, Mimetesite 3(Pb,3AsOj,PbCL Vanadiuite 3(Pb,2VOJ,PbC!,
QUESTIONS AND EXERCI L
546, State the source of phosphorus.
641. Give equations or diagram^ explaiiato y f tl lat n of phospiiorue From its natural compounds.
648. What ia the composition of farmers' " ] 1 1 o^phat aud how prepared ?
549. Enumerate the properties of phosphoru
550. Mention some solvents of phosphorus.
551. How ia the oflBcial Dilutea Phoephoric Acid made ?
553. Describe the precautions necessarj to be observed in making this acid.
553. What ia the strength of the official a«id !
554. Write formulre illustrative of all claasea of orthophosphates.
555. Mention the chief tests for soluble and insoluble phosphates.
556. By what reactions may phosphates be distinguished from arscuiates ?
BOBACIC ACID AND OTHER BORATES.
Formula of Boracic Acid HjBOj. Molecular weight 62.
The composition of artificial bofacic acid is expressed by the for- mula HsBOj; but at a temperature of 212° P. this body loses the elementa of water and yields metaboracic acid, HBOj. The latter acid exists in the jets of steam (fumeroUes or saffioni'j that issue from the earth in some districtsof Tuscany, and colleets in the water of the lagoni (lagoons or little lakes) formed at the orifice of the steam-channel. Neutralized by carbonate of sodium the acid liquid gives common borax (2NaBO2,B,Oj,10HiO), a salt containmg, probably, metaborate of sodium, boracic anhydride, and water of crystallization ; it appears to be analogous in constitution to the red chromate of potassium and other similar abnormal salts. It occurs " in transparent colorless crystals, sometimes slightly effloresced, with a weak alkaline reaction; insoluble in rectified spirit, soluble in water." Borax is also found native, particularly in Thibet. Fused borax readily iJissolvea metallic oxides, as will have baen already
id .y Google
BORATES. 275
noticed in testing for cobalt and manganese. Hence, besides its nae in medicine (Sodce Borax, U. S. P.; Borax^ Mel Borneis, B, P., or Mei Sodce Boratia, U.S. P., and Glycermum Boracia, B. P.), it is employed as a fins in refining and other metallurgic and ceramic operations.
Qurmtivtdence. — The boracic radical is trivalent (BO,'"), the motaboracie, univalent (BO/); they have not been isolated. The element boron, like carbon, occurs in the amorphous, graphitojdal, and crystalline conditions. It is a trivalent element (B'"), yielding deflnite sails, such as the chloride (EClj) and fluoride (BF,). Its atomic weight is II.
Reactions.
First Synthetical Beaction. — To a hot solution of a crys- tal of borax add a few drops of sulphuric acid and set aside ; on cooling, crystalline scales of boracic acid {HgRO^) are deposited. They may be purified by collecting on a filter, slightly washing, drying, digesting in hot alcohol, filtering, and setting aside; pure boracic acid (B. P.) is deposited. The acid may also be recrystatlized from water. Fifty grains dissolved in one ounce of rectified spirit con- stitutes " Solution of Boracic Acid," B. P.
When heated, these crystals lose water and yield, first, mctaboracic acid (HBOj), and subsequently, when fused, boracic anhydride (BjO^).
Second Synthetical Beaction. — Mix together 1 part of boracic acid, i of acid tartrate of potassium, and 10 or 20 of water; evaporate to a syrupy consistence, spread on plates, and set aside for dry scales to form. The resulting substance is far more readily dissolved by water than its constituents, and is known as boro-tartrate of potassium, soluble tartar, or soluble cream of tartar. The Prussian tartarus boraxatus differs from the foregoing French variety in containing 1 part of borax to 3 of acid tartrate of potas-
Analytical Meaclions { Tests).
First Analytical Meaclion.^Dip a piece of turmeric paper (papci boifeed in tmctuie of turmeric tubers and dried) ijito a solution of boracic acid ; it is colored brown-red, as bj alkalies
rhe usual way of applving this test is as follows : Add to the borate a few drops of hydrochloric acid, immerse half of a slip of turmcuc paper in the liquid then remove the hydrochloric acid by (tiying the papei over a flame Concentrated hydrochloric acid and ferric chlonde produce a somewhat similar eflect.
id, Google
275 SALTS OF ACIDULOUS EADIOALS.
Second Analytical Beaotion — To a fragment of a borate (borax, for example) in a small disb or watch-glaaa add a drop of sulphuric acid and then a little alcohol, warm the mixture and set light to the spirit; the resulting flame will be tinged of a greenish color at its edges by the volatilized b Oracle acid,
The liquid should be well stirred while burning'. Salts of copper and some metallic chlorides produce a somewhat similar color.
Other Analytical Eeactions. — In solutions of normal bo- rates (NajBO, e. g.) barium salts give a white precipitate of barium borate (Baa2B0j) soluble in acids and alkaline salts. Nitrate of silver gives borate of silver (Ag^BOa) soluble in nitric acid and in ammonia. Chloride of calcium, if the solution is not too dilute, gives white borate of calcium.
The foregoing acids and other salts contain the oidy addvloua radicals thai are eommordy met with in analysis or in ordinary pharmaceutical o})erations. There are, however, many others which occasionally present themselves. The chi^ of these loill novi be shortly noticed ; they are arranged in alphabetical order to facilitate reference.
SALTS OF RARER ACIDULOTIS RADICALS.
Benzoic Acid (HC,HjO„) and other Benzoateb Slowly
heat a fragment of benzoin (Benzoinum, B. P. and U. S, P.) in a test-tube ; benzoic acid (Acidum Henzoicum, B, P. and U. S. P.) rises in vapor and condenses in small, white, feathery plates and needles, on the cool sides of the tube. Or boil the benzoin with one-fourth its weight of lime, filter, concentrate, decompose the solution of benzoate of calcium by hydrochloric acid, collect the precipitated benzoic acid, press between paper, dry, and snblime in a tabe or other vessel.
2HC,R0„ -f- Ca2H0 = Ca2C,H,0, + 211,0
Ca2C,HjO, -f 2HC1 = CaCl, + 2HC,H,0,
There is always associated with tlie product a mintite quantity of a volatile oil of agreeable odor, suggesting that
id .y Google
BENZOATES. 211
Benzoate of Ammonium.. — To a little benzoic acid add a few drops of solution of ammonia ; it readily dissolves, forming benzoate of ammonium (Ammontee BenzoaSfB. P. (NH.C,H.OJ.
HCjHjO, + NH^HO = NH,C;H,0^ + H,0
On evaporation, acid crystals or, ammonia being added, neutral crystals of benzoate of ammonium are deposited.
Properties. — Benzoic acid is also soluble in otlier alkaline lic|uids, forming benzoates. It is slightly soluble in cold water, more so in hot, and readily soluble in rectified spirit. It melts at 248° F^ and boils at 462°, evaporating with only a slight residue.
rests, — Tlie following are the tests for benzoic acid : To a portion of the above solution of benzoate of ammonium add a drop or two of sulphuric or hydrochloric acid ; a white crystatlioe precipitate of benzoic acid separates. To another portion, carefully made neutral, add a drop or two of neutral solution of perchloride of iron ; reddist ferric benzoate is precipitated. Benzoic acid is distinguished from an allied body, cinnamic acid (occurring in Balsams of Pern, Toiu, and Storax), by not yielding hydride of benzoyl (CjH.OH) (oil of bitter almonds) when distilled with chromic acid — that is, with a mixture of red chromate of potassium and sulphuric acid.
Benzoic acid is said to be largely produced at a cheap rate from naphthalin, one of the by-products in the distilla- tion of coal for gas (Chemical News, xvi. p. 296.)
Oabminic Acid (OuHuOg). — Tliis is tlie coloring principle of cochi- neal (CoccM, B. P. and U. S. P.). The carmine of trade, when unadulterated (vide Pliarmaceutical Jonrnal, 1859-60, p. 546), is curminie a«id united with about five per cent, of alumina, or, occa- sionally, of oxide of tin or albnnieii. It should be wholly soluble in eolation of ammonia. Carmine, with French chalk, or starch, con- elitiites face-rouge or animal rouge.
Cetbaric Acid (HjCj.HjjOjj) is the bitter principle of Iceland moss (Cetraria, B. P. ana U. S. P.), In the lichen it is associated with much starch.
Ohbysophanic Acid (OkIIjOj?). This acid is the chief coloring- matter of various species of rhubarb root {RkeiJiadia:,'B.'P.,Itheiiin, TJ. 8. P.) and parmelia. It may be obtained in crystals of a golden- yellow color, hence the name (from arpwrof, chrusoe, gold, and fmtw*, pkaind. I shine). Its synonyms are RhaponHaft, Eheic acid, Rlimn, Rhenmin, Rkuharbarie add, Rhnbarbarin, Rumicin. Ohryso- ph an ic acid, black, red-brown, and red resins (Aporetine, PIkeotk- 24
id .y Google
2T8 SALTS OP RARER ACIDULOUS RADICALS.
tine, and Erifihrorelme^, a bitter principle, and tannic acid are con- sidered ia be the conjomt source of the therapeutic properties of rhubarb.
Cyanic Aoid (HCyO) asd other Ctanatbs The valu- able veducing-power of cyanide of potassium (KCy) (or feiTocyanide, K,Fcy) on metallic compounds is due to the avidity with which it forms cyanate(KCyO),
Process. — Fuse a few grains of cyanide of potassium in a email porcelain crucible, and add powdered oxide of lead ; a globule of metallic lead is at once set free, excess of the oxide converting the whole of the cyanide of potassium into cyanate of potassium.
Prea.— Cyanate of potassium (KCNO), or, better, cyanaf« of lead (Pb2CN0}, treated with Bulphabe of ammonium, yields cjanate of ammonium (NHjONO) ; and solution of cyanate of ammonium, when simply heat«d, changes to artificial urea (OHjN,0), the most import-ant constituent of urine, and the chief form in which the nitro- Ken of food is eliminated from the animal system. The process will be more fully described subseqaeBtly in connection with urea,
PoRaic Acid (HCHO,).— The red ant {Fcn-mica rufa) and several other insects, when irritated, eject a strongly acid, acrid liquid, hav- ing a composition expressed by the above formula, and which has appropriately received the name of formic acid ; it is also contained in the leaves of the stinging-nettle.
Process. — It may be artificially prepared by heating equal weights of oxalic acid and glycerine to a temperature of from 212° to 220° for fifteen hours. The glycerine has, apparently, no chemical action, but, for some unknown reason, induces decomposition of the oxalic acid at a lower temperature than would otherwise be necessary ; at a higher temperature the formic acid itself is decomposed. On dis- tilling the mixture with water the formic acid slowly passes over. The dilute acid may be concentrated by neutralizing with carbonate of lead, filtering, evaporating to a small bulk, collecting the deposited crystalline formate of lead, drying, decomposing in a current of sulphuretted hydro- gen, and separating the resulting syrupy acid, or distilling the formate of lead with strong sulphuric acid. Iin n, = HCHO, -|- CO.
O^a-fin Foiniio Csrboule
sdd. acid. acid gas.
Formic add may be instructively though not economically pre- pared by the oxidation of methylic alcohol (wood-spirit), just as acetic acid and valerianic acid are obtained from ethylic alcohol and amy lie alcohol respectively.
CH,HO + 0, = HCHO, -1- H,0
id .y Google
Tests.— Formia acid does not cliar wlien lieated aloiiB or witii siil- phnric acid, hat splits up into carbonic oxide ^as and water. It is recognized by this property and by its reducing-action on salts of gold, platinum, mercary, and silver. It is solid below 32'^.
Gallto Acid See Tannic Acid.
Hemidesmio Acid. — The supposed active principle of hemideamus root (Hemidesmi Radio;, B. P.).
Hrpp0Eio Acii> (HCgHgNO,) is a constituent of hnman urine (mnch increased on taking benzoic acid), but is best prepared from the urine of the horse (hence the name, from iitwoj, hippos, a horse), or, better, from that of the cow. To snch urine add a little milk of lime, boil for ft few minntes, remove precipitated phosphates by filtra- tion, drop in hydrochloric acid until the liquid, after well stirring, is exactly neutral to test-paper, concentrate to about on^eighth the original bulk, and add excess of strong hydrochloric acid ; impure hippuric acid is deposited, From a solution of the impare acid in hot water chlorine gas removes the color, and tbe liquid deposits cr^tals of pure hippuric acid on cooling. Its constitution ia that of benzoic glycocine, G.,UJ,G.Ufi) (NHjjO,.
Tests. — To a solution of hippurate add nentral solution of ferric chloride ; a brown precipitate (ferric hippurate) resuite. Salts of silver and mercury give white precipitates. Heat hippuric acid in a test-tube; it chars, benzoic acid sublimes, and vapors of characteristic odor are evolved; they contain, amongst other bodies, hydrocyanic
acid and a substance smelling somewhat like Tonka bean. The
crystalline form of hippuric acid ia characteristic i it will be described in connection with the subject of urine.
QUESTIONS AND EXERCISES.
557. Give the preparation, composition, properties, and tests of benzoic acid, employmg equations or diagi'ams.
558. What is the nature of carmine ?
559. Name the bitter principle of Iceland moss.
560. Mention the coloring principle of rhubarb,
661. To what is rhubarb considered to owe its medicinal activity?
562. How is cjanate of potassium prepared, how converted into an ammonium salt, and- what the relations of the latter to urea ?
563. Give the formulae of cyanic acid, cyanate of ajumonium, and
564. What is the chemical formula of formic acid ?
565. Describe the artificial production of formic acid.
566. Describe the relation of formic acid to wood-spirit, 667. State the sources, characters, and tests of hippuric acid.
HYDROPEKSocriurc Acm (HjPc"Oy„ or HjPcy"") and othbe FBiiitooYANiDRS.— The ferrocyanide of most interest is that of potas- sium [Potassii Ferrocyanidum, U. S. P.), the yeiiow prnssiatc of
id .y Google
280 SALTS or RARER ACIDULOUS RAillCALS.
potash {PotasstB Prussias Flava, B. P.) (K^FeO,Nj, SH^O), the formation of which was allnded to in connection with hydroojanic acid (see page 229). It cannot he regarded as simply a double salt of cyanide of potassinm with cyanide of iron (FeCy,, 4KCj), its chemical properties being entirely different from either of those suh- stancea ; moreover, unlike cyanide of potassium, it is not poisonous. Most of its reaetionB point to the concfnsion that its iron and cyano- gen are intimately nnited to fonn a definite quadrivalent radical . appropriately termed /eri^cj/cwiojfero (FeCyj, or Fey). One part of ferrocyanide of potassium in 20 of water forms the official "Solution of YeUow Prussiate of F6tasK," B. P.
Tests. — Many of the ferrocyaiiides are insolnble, and are therefore precipitated when solution of ferrocyanide of potaasiuin is added to the various salts. Those of iron and copper being of characteristic color, are adopted aa tests of the presence of the metals or of the ferrocyanogeii, as the case may be.
3K,Pcy + 2(Fe,3SOJ = Pe,Pcy, + SK^SO,.
To solution of ferrocyanide of potassium add a ferric salt ; ferrocyanide of iron (Fe^Fcy,) (Prussian Blue) {Ferri Ferrocyaniduvi, TJ. S. P.) is precipitated.
To another portion add solution of a copper salt ; red- diah-brown ferrocyanide of copper (CUaFcy) ia precipitated.
iVo^e.— The fen-ocyanogen in ferrocyanide of potassium is broken up when the salt is heated with sulphuric acid, carbonic oxide being involved if the acid is strong, and hydrocyanic acid if weak : —
K.FeOjN, 4- 6H,0 + GHjSOj = 2K,S0j + FeSO,
+ 3(NHJ580. + 6C0.
2K.FeCy, + 6H,S0, + xH^O = FcK^FeCy^ + 6KHS0,
4- 6HCj + xHjO.
Hydrocyanic Add has already been described. ( Vide p. 230.)
Carbonic oxide (00). — Heat two or three fragments of ferrocya- nide of potassiam with eight or ten times their weight of eolphnric acid, and, as soon as the gas begins to he evolved, remove the test tube from the flame; for the action, when once set np, proceeds somewhat tnmultuoasly. Ignite the carbonic oxide at the mouth of the tnhe ; it burns with a pale blue flame, the product of combustion being carbonic acid gss (COj).
Carbonic oxide ia a. direct poison. It is generated whenever coke, charcoal, or coal burns with an insufficient supply of air. Hence the danger of open fires in the more or less closed apartments of ordinary dwellings.
Carbonic oxide may also be obtained from oxalic acid. ( Vide p.
id .y Google
PEHRIDCYANIEBS. 281
IIydroferridcyanic Acid (II^Fe'^^Cj',,, or H'^Fdcy*'') AND OTHER Feeeidcyasibes. — Pflss chlonne gas through solution of ferrocyanide of potassium until the liquid ceases to give a blue precipitate, when a minute portion is taken out on the end of a glass rod and brought into con- tact with a drop of a dilute solution of a ferric salt ; it now contains ferridcyanide of potassium ('K.BFe"\Cy,„, or K'[,Fdey'''), red prussiale of potash (B. P.), as it is tefmed from the color of its crystals; —
2K'^Fe"Cy'a + CI', = 2K'Ci' + K'„Fe/"CyV
Note.— The removal of two atoms of potassium from the ferrocyri- aide is the only change of composition that occurs; hnt the ferrocya- nogen is altered in quality, ita iron jjasaing from the ferrous to the ferric condition, from hivalent to trivalent activity, a condition in which it no longer precipitates ferric salts, but, on the other hand, gives a dark-bine precipitate with ferrous salts. The radical is dis- tinguished as ferridcyanogen.
Test. — To a portion of the solution add solution of ferrous sulphate; a precipitate falls. This precipitate is ferridcyanide of iron (TurnbuU's blue), Fe"5Fe'"aCy',3,or Pe",Fdcy^'.
KjFdcy + 3FeS0, = Fe3Fdcy -f 3K,S0,.
It will be noticed that this change in the condition of the iron keeps ap the balance of the atomic values of the various parts of the radicals or of the salts ; the quantivalential equilibrium is maintained.
A solution of 1 of ferridcyanide of potassium in 20 of water con- stitutes the " Solution of Red Prossiate of Potash," B. P.
HYDROFLnORIC ACID (HP) AND OtHER FLUOEIDES. —
Molecular weight of HP, 20. The chief use of hydrofluoric acid is in the etching on glass. The operation, performed on the small scale, also constitutes the best test for fluorine, the elementary radical of all fluorides.
Process and Test. — Warm any odd piece of window- glass, having an inch or two of surface, until a piece of beeswax rubbed on one aide yields a thin oily film. When cool make a cross, letter, or other mark on the glass by pressing a pointed piece of wood, a penknife, or flie, through the wax. Place two or three grains of powdered fluor spar, the commonest natural fluoride, in a small porcelain crucible, add a drop or two of sulphuric acid, cover the crucible with the prepared glass, waxed side downwards, and gently warm the bottom of the crucible in a fiime-chaniber or in the open air, in such a way as not 24*
id .y Google
282 BALIS op BARER ACIDULOUS RADICALS.
to melt the wax. After a few minutes remove the glass, wash the waxed side by pouring water over it, scrape off moat of the wax, then warm the glass, and wipe off the remainder ; the marks made through the wax will be found to be permaneutly etched on the glass ; the acid has eaten into or etched (from the Oermaii atzen, to corrode) the glass.
In the above operation the flnoride of calcinm and sulphuric acid yield hydrofluoric acid, thus :—
CaFj + H,SO, = CaSO, + 2HF.
The bydroflaoric acid gas and the silica of the glass then yield
gaseous fluoride of silicon (SiP,), which escapes, and water, thus: —
4HP + SiO, = 2HjO + SiP,.
The silica being removed from the glass, leaves furrows or etched
Note. — In the experiment just described, the liberated hydrofluoric siiCiA also attacks the siliceous glazing of the porcelain cracible; so that in important cases, where search is made for very small qnanti- ties of fluorine, vessels of platinnm or lead must be employed.
Uses. — The aqoeona solotion of hydroflnoric acid used by etchers, and commonly termed simply hydrofluoric acid, or fluoric acid, is prepared in leaden stills and receivers, and kept in leaden or gutta-
Sercha bottles. Except these materials, as well as platinnm and nor spar, hydroflnoric acid rapidly attacks any substance of which bottles and basins are nsoally made. It quickly canterizes the skio, producing a painful slow-healing sore.
Quantivale'ace.—'FhG atom of fluorine, like that of chlorine, bro- mine, or iodine, is univalent (F'l. The great analogy existing be- tween these radicals extends to their comnonndt^.
Fluorine is said to be a colorless gas ; bat, from the avidity with which it combines with all elements (escept oxygen), it is so difficult of isolation as hitherto to preclude satisfactory study of its physical properties.
Hypophosphokous Aoid (HsPOj, or HPHjO J and othee Hypo PHOSPHITES. — Boil together, in a fume-chamber, a grain or two of phosphorus, a few grains of slaked lime, and about a quarter of an ounce of water until phoepho- retted hydrogen, a spontaneously inflammable, badly smell- ing gas, ceases to be evolved. The mixture, filtered, yields solution of hypophospbite of calcium (Ca2PHjOa).
Pg + 6H,0 -1- SCaHjO^ = 3(Ca2PHjO^ -f 2PH,.
The solution, when concentrated by evaporation, has been known to explode, probably from formation of phosphoretted liydrogeu. This may be prevented, it is said, by evaporating at a low tempera- " towards the close of the operation ; or by adding
id .y Google
HYP0PH08PH0E0US ACID. 283
alcoliol. wliich decomposes any traces of liquid phosphoretted hydro- gen (PHj) or solid plioaphoretted hyclro^ii (F5H) which possibly may be present, and to which it is coneeivabie explosion may be due. (ir; PhoBphoreited hydrogen (PHj). — The above reaction is also that by which phosphoretted hydrogen, the third hydride of phosphorus,, may be prepared. If the gas is to be collected, the phosphorus and water may first be boiled in a flask until spontaneously a jet of phoB- phorns vapor escapes, with steam, from the cod of the attached de- livery-tube. Strong sointion of caustic potash or soda is next very ffradually ponred into the flask through a fnnnel tube previously fitted into the cork, the liquid being kept boiling. Phosplioretted hydrogen ia then evolved, and if the delivery-tube dip under water may be collected, or allowed to slowly pass np through the water bubble by bnbble so as to form the peculiar rings of smoke (phoa- phoric anhydride) characteristic of the experiment.
Hypo^hosphite of cata'wm. may be obtained in crystals ; but the solution IS uaaally at once evaporated to dryness, a white pulvemlent salt being obtained. Other hypophosphites may be obtained in the same way from other hydrates, or by double decomposition of the calcium salt and carbonates. Hypopnosphorous acid, the hydrogen hypophosphite, may be prepared by decomposing the calcium salt by ojcalic acid; hypophosphite of quinine by dissolving the alkaloid in hypophosphorous acid, or bydecomposing sulphate of quinine by hypophMphit« of barium. The hypophosphites are often used in medicine in the form of syrups. The term hypophosphite is in allu- sion to the smaller amount (vHo, hupo, under or deficiency) of osygeu in these compoands (R'jPOj) than m the phosphites (BjPOj), a class of salts having again less oxygen in their molecules than exists in those of the phosphates (BjPOj), The prefix hyno has similar sig- nificance in such words as hyposulphite and hypochlorite.
Tests. — To a portion of the above sointion of Jiypophos- phite of calcium add solution of chloride of barium, chlo- ride of calcium, or acetate of lead ; in neither case ia a precipitate obtained, whereas soluble phosphates and phos- phites yield white precipitates of phosphate or phosphite of bariam, calcium, or lead. To other portions add solu- tions of nitrate of silver and mercuric chloride; the re- spective metals are precipitated as by phosphites. To an- other small portion add zinc and dilute sulphuric acid; hydrogen and phosphoretted hydrogen are evolved as from phosphites. To another portion add sufficient oxalic acid to remove the calcium; filter; to the solution of hypo- phosphorous acid add solution of sulphate of copper and slowly warm the mixture ; solid brown hydride of copper is precipitated ; increase the heat to the boiling-point ; hydrogen is evolved and metallic copper set free. Heat a small quantity of a solid hypophosphite on the end of a spatula in a flame ; it splits up into pyrophosphate, phos-
id.y Google
2H4 SAT.TW OP RARER ACIDULOUS RADICALS.
phoretted hydrogen, and water, burning with a phospho- rescent light.
3(Ca2PHgO,) = Ca,P^O, + SI'H, + H,0.
IIyposulphueous Acid (H,S.,0,) and other Hyposul- phites,— The only hyposulphite of much interest in phar- macy is the sodium salt (Hyposulphite of Soda, B. P.) (Na,S,0„5H,0).
Process. — Heat together gently, or set aside in a warm place, a mixture of solution of sulphite of sodium (Na^SO^), and a little powdered sulphur; combination slowly takes place, and hyposulphite of aodinm is formed. The solution, filtered from excess of sulphur, readily yields crystals. [The solution of sulphite of sodium may be made by satu- rating a solution of soda with sulplinrous acid gas.]
Use of hyposulphite of sodium in quantitatioe analysis. — In the British Pharmacopoeia hyposulphite of sodium is given as a reagent for the quantitative estimation of free iodine in volumetric analysis. To a few drops of iodine- water add cold mucilage of starch; a deep-bltie color (starch iodide) is produced. To the product add solution of hyposulphite of sodium until the blue color just disappears. This absorption of iodine is sufficiently defi- nite and delicate to admit of application for quantitative purposes. It depends on the combination of the iodine with half of the sodium in two molecules of the hyposul- phite, the hyposulphurous radicals of the two molecules apparently coalescing to form a new radical, tlie tetrathionic (from f f rpo(, teiras, four, and Bftov. theion, sulphur), — tetra- thionate (Na^SjOg) and iodide of sodium being formed.
Stdphur antacids. — It will be as well here to give the formulee of three other oxyacids of sulphur, forming with the four nlreody mentioned a series that ia as nseful as the aeries of compomids of nitrogen and oxygen in illustrating the soundness of Dul ton's atomic theory (p. 36).
Sulphurous Acid H,SO,
Sulphuric Acid H,SO,
Hyposulphurous Acid HjSjO,
Dithionic Acid H,S,Oa
Trifhionic Acid H^SsO,
Tetrathionic Acid HjS.Oa
Pentathionic Acid HjSjO,
Vse of "Hypo " in Photography. — The sodium hyposul- phite is largely nsed in photography to dissolve chloride, bromide, or iodide of silver off plates which have been
id .y Google
exposed in the camera. Prepare a little chloride of silver by adding a chloride {chloride of sodium) to a few drops of solution of nitrate of silver. Collect the precipitated chloride on a filter, wash, and add a few drops of solution of hyposulphite of sodium; the silver salt is dissolved, solution of double hyposulphite of sodium and silver being formed. The solution of this double hyposulphite has a remarkably sweet taste, sweeter than syrup. The double hyposulphite of sodium and gold is employed for giving a pleasant tint to photographic prints.
Test. — To solution of a hyposulphite add a few drops of dilute sulphuric or other acid; hj'posulphuroue acid is set free, but at once begins to decompose into sulphurous acid, recognized by its odor, and free sulphur (2H„SjOj= SHjSOb + S,). This reaction constitutes the best test for hyposulphites. Another good test of a soluble simple hyposulphite is its power of dissolving chloride of silver with production of a sweet solution.
QUESTIONS AND EXERCISES.
568. Give the formnla of feri'ocyanide of pofassium.
569. What is the supposed conatitution of ferrocyauide ofpotaa-
510. Ennmeral* the tests for ferrocyanogen.
571. What are the respective reactions of ferrocyauide of potas- sium with strong and weak suipliuric acid?
572. Mention and explain a common source of carbonic oxide in households !
573. Write equations or diagrams illustrative of the changes effected on feirocyanide of potassium during its conversion into fecrid- cyauidc.
574. By what reactions may the presence of a ferridcyanide in a solution be demonstrated?
575. State the difference between Prussian hlue and Turnhull's
576. Describe the source, mode of preparation, chief use of, and test for hydrofluoric acid.
577. Illustrate by a diagram the preparation and composition of hyposulphite of sodium.
578. Mention the uses and characteristic reactions of hyposulphite of sodinm.
579. Gfive the names and formulie of seven acids, each containing hydrogen, sulphur, and oxygen.
I^CTic AoiB (HjCjHiOa) AHD OTHBE LACTATES. — Wheu milli turns sour its sugar has become converted into an acid appropriately tei'med lactic (iac, lacl-is). Other saccharine and amylaceous sab-
id.y Google
Btances also by fermentation yield iactic acid. Noitliev the liydrogen lactate (lactic a^id) nor other lactates are mnch used in England, bat the former ia official in America {Acidum Lanticwia, TJ. S. P.).
Process. — Lactate of calcium and lactic acid may be pre- pared as follows; Mix together eight parts of stigar, one of common 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 lactate of calcium re- sults. Eetnove these, vecrystallize from hot water, decom- pose by sulphuric acid, avoiding excess, digest in alcohol, filter off the sulphate of calcium, evaporate the clear solu- tion to a syrup ; this residue is lactic acid ; sp. gr. 1.212.
Lactate of Iron (Ferri Lactas, U. S. P.) is made by digest- ing iron filings in warm diluted lactic acid (1 acid to 16 water) till effervescence of hydrogen ceases, filtering and setting aside to cool and crystallize. The crystals are col- lected, washed with alcohol, and dried. This ferrous lac- tate occurs in greenish-white crystalline crusts or grains, of a mild, sweetish, ferruginous taste, soluble in forty- eight parts of cold, and twelve of boiling water, but inso- luble in alcohol. Exposed to heat it froths np, gives out thick, white, acid fumes, and becomes black ; sesquioxide of iron being left. If it be boiled for fifteen minutes with nitric acid of the specific gravity 1.20, a white, granular deposit of mucic acid will occur on the cooling of the liquid.
Test. — No single reaction of lactic acid ia sufficiently distinctive to form a test. The crystalline form of the lactate of calcium, as seen by the microscope, ia charac- teristic. The production of this salt, and the isolation of the syrupy acid itself, are the only means, short of quanti- tative analysis, on which reliance can be placed.
A variety of lactic acid has been obtained from the juice of fish ; it is termed sarcolactic acid (from odpl, gen. onjixoi, flesh).
Malic Acid (H^C^H^Oj) and other Malates (from malum, an apple).— The juice of unripe apples, goose- berries, currants, rhubarb stalka, tSic, contains malic acid and malate of potassium. When isolated it occurs in deliquescent prismatic crystals.
Tests. — Malate of calcium (CaHC.HjOj) is soluble in water; hence the aqueous solution of malic acid or other malate is not precipitated by lime-water or chloride of calcium ; but on adding spirit of wine a white precipitate falls, owing to the insolubility of the calcium malate in alcohol. Malates are precipitated by lead-salts ; on warm-
id .yCoOglc
METAPnOSP HATES. 28T
ing the uialatc of lead with acetic acid it dissolves, sepa- rating out in acicular crystals on cooling. If the mixture be heated without acid the malate of lead agglutinates and fuses.
Hot strong snlpliuric acid chars malic acid fw less readily than it does nearly all other organic acids.
Malic acid is one of the chief products of tie action of nitrous acid on asparagin (0,HsNj03,H 0), a crystalline body extracted from asparagna and marshmailow {AUhea, TJ. S. P.).
Meconio Acid (HgOjHO,). — Opium contains meconic acid (from /.jjiuw mikon, a poppy) partially combined witii morphia. To concentrated infusion of opium, nearly neu- tralized by ammonia, add solution of chloride of calcium, meconate of calcium is precipitated. Wash the precipitate, place it in a small quantity of hot water, and add a little hydrochloric acid ; the clear liquid (filtered, if necessary) deposits scales of meconic acid on cooling.
Test. — To solution of meconic acid or other meconate, or to infusion of opium, add a neutral solution of ferric chloride ; a red solution of meconate of iron ia produced. To a portion of the mixture add solution of corrosive sub- limate; the color is not destroyed: to another portion add hydrochloric acid ; the color is discharged. (These reagents act on sulphocyanate of iron, which is of similar tint, in exactly the opposite manner.)
The normal meconates of pota^um, sotlinm, and ammonium are solnble in water, the acid meconates very slightly soluble, tlie meco- nates of barium, calcium, lead, copper, and silver insoluble in wat«r bnt solnble in acetic acid,
Metaphosphorio Acid (HPO,) and other Mbtaphos- PHATES. — Prepare phosphoric anhydride {^.p^) by burning a small piece of phosphorus in a porcelain crucible placed on a plate and covered by an inverted test-glass, tumbler, half-pint measure-glass, or some such vessel. After wait- ing a few minutes for the phosphoric anhydride to fall, poui' a little water on the plate and filter the liquid ; the product is solntion of metaphosphoric acid {fi'om jitto, ineta, a preposition denoting change).
P^Os -I- H,0 = 2HP0,.
Tests.— T^o solution of metaphosphoric acid add ammo- nio-nitrate of silvei', or to a neutral metaphosphate add solution of nitrate of silver ; a white precipitate (AgFO„)
id .y Google
is obtainccl. This reaction sufficiently distinguishes meta- pliosphates from the ordinary phosphates or orthophos- phatea (from dp9o(, orlhos, straight), as the common phos- phates may, for distinction, be termed (which give, it will be remembered, a yellow precipitate with nitrate of silver). Another variety of phosphates shortly to be considered, the pyrophosphates, also give a white precipitate with nitrate of silver. 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 orthophos- phoric nor pyrophosphorie 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 orthophos phoric acid:^
HPOj + H,0 = H,PO,.
The ordinary medicinal phosphoric acid is made fi'om phosphorus and nitric acid, the liquid being evaporated to a syrupy consistence to remove the last traces of nitric acid. It may contain pyrophosphorie and metaphosphoric acids, if the heat employed be high enough to remove the elements of water : —
H^PO, — H,0 = HFO,.
On redilution the metaphosphoric acid only slowly reab- sorbs water. If. therefore, on testing, metaphosphoric be found to be present, the solution should be boiled until conversion to ortho phosphoric acid has occurred.
Nitrous Acid (HNOJ and othek Nitrites.— Strongly heat a fragment of nitrate of potassium or of sodium on a piece of platinum foil ; oxygen is evolved and nitrate of potassium remains.
Test. — Dissolve the residue in water, add a few drops of dilute snlphuric acid, then a little weak solution of iodide of potassium, and, lastly, some mucilage of starch ; the deep-blue compound of iodine and starch is at once pro- duced. Ecpeat this experiment, using nitrate instead of nitrite; no blue color is produced.
SHI + 2HN0, = 3H,0 + 2N0 4- I,.
Test for Nitrites m Water. — This liberation of iodme by nitrites and not by nitrates is a reaction of considerable value in searching for nitrites in ordinary drinking-waters, the occnrreooe of sneh salts beiDg held to indicate the prRsence of nitrogenous organic matter in
id .y Google
PHOSPHOROUS ACIDS. 289
a state of oxidation or dacay. The salph^iric acid used in the ope- ration most be pure, and the iodide of potassium free from iodafe.
Commerciai N%trov,& Add. — The liquid commonly t«rmed in pharmacy nitrona add is simply nitric acid impure from the presence of nitrous acid.
The only nitrite used in medicine is a nitrite of aa organic basy- lous radical, ethyl; nitrite of ethyl (CjHjNOj), or niti'ons ether, ia the chief constituent of "sweet spiWi of nitre" [Spiritus ^theris Nitroei, B. P. and U. S. P.: vide Index).
Fhosphokous Acid (HjPOj, or HjPHOA— It is necessary to notice this compound in order that the reader may have brought before him the three acids of phosphorus, namely, phosphoric acid (HjPOA phosphorous acid (H.PHOj), and hj^ophosphorous acid (HFHjO,) ; it will be noticed that in composition they differ from each other simply in the propc ■" " " ' '
tainin^ fonr, three, and two a they differ by the hypothetical phosphoric radical or grouping being trivalent, the phosphorous bivalent, and the hypophosphorous univ- alent. These three acids and corresponding salts must not be con- founded with pyrophosphoric and metaphosphoric acids and salts; the former are acids of phosphorus ; the latter, varieties of phos- phoric aeid ; the former, in composition, differ from ea«h other in the proportion of oxygen they contain; the latter, by the elements of
Aoids of Phosphorus. Varieties of phosphoric acid.
H3PO4 phosphoric acid. HaPO, (ortuolpnosphoric acid.
H^HOjohosphoroneacid. HjPjO, pyrophosphoric acid.
HPHgOj hypophosphorous acid. HFO, metaphosphoric acid. When hypophosphorous acid ia exposed to the air, oxygen is absorbed and phosphorons aeid results; bj" prolonged exposure more oaygen is absorbed and phosphoric acid is obtained. When phosphoric acid, or rather, for distinction, orthophosphoric acid ia heated, every two molecules yield the elements of a molecule of water, and pyrophos- phoric acid results ; by prolonged exposure to heat more water ia evolTed, and metaphosphoric acid is obtained. These differences will be further evident if the formulse be written empirically, nearly all being doubled, thus; —
HjPjOj hypophosphorous acid.
HjPjOj pnosphoroos acid.
H P O I plif*pli<"''0 *eid, or ' ' ' I orthophosphoric aeid.
HjPjO, pyrophosphoric acid.
HjFjOj metaphosphoric acid.
phi^phorio acid H.P.O,.
phosphorous acid
hypophosphorous acid metaphosphoric acid
HeP^O,. HjPjO„.
25
id .y Google
3SI0 SALTS OF RARER ACIDULOUS RADICALS.
From the central compound, phosphoric acid, the acids of phosphorus differ by regularly diminiBhing proportions of the element oxyg'cn (see previous page), the varieties of phosphoric acid by regularly dimiuishing proportions of the elemente of water.
Prepare phosphorous add by exposing a moist sticlt of phoaphorns to the air; a thin stream of heavy white vapor falls, which is the acid in question. The best method of collection is to place the stick in an old test-tube having a hole in the bottom, to support this tube by a funnel or otherwise, the neck of the funnel being supported in a bottle, test-glass, or tube, at the bottom of which is a little water. Having collected some phosphorous acid in this way, apply the various tests already alluded to under Hypophosphorons Acid, first carefully neutralizing the phosphorous acid by au alkali. The means by which the varieties of phosphoric acid are distinguished have been given under Metaphonphoric Acid.
Other soluble phosphites are prepared by neutralizing phosphorous acid with alkalies, and the insoluble phosphites by double decomposition.
Pyeogallio Acid. — See Tannic Acid.
Pyrophosphoric Acid (H,P 0,) and other Pyrophos- phates.— Heat ordinary phosphate of sodium (Na HPO„ 12H,0) in a crucible; water of crystallization is first evolved, and dry phosphate (Na^HPOj) remains. Continue the heat to redness ; two molecules of the salt yield one molecule of water, and a salt having new properties is obtained: —
2Na,HP0, — H,0 = Na,P,0,.
It vi termed pyrophosphate of sodium, in allusion to itfi origin (rfJp, jwlr, fire). Other pyrophosphates are produced in a similar way, or by double decomposition and precipitation, or by neutraliz- ing pyrophosphoric acid by an oxide, hydrate, or carbonate. Possi- bly the pyrophosphates are only compounds of orthoplioephates with metaphospbat«s : —
Na,P,0, = Na^PO^KaPO,.
Tests. — To solution of a pyrophosphate add solution of nitrate of silver; white pyrophosphate of silver (Ag^P^Oj) falls as a dense white powder, differing much in appearance from the white gelatinous metaphosphate of silver or the yellow orthophosphate. To pyrophosphoric acid, or to a pyrophosphate mixed with acetic acid, add an aqueous solution of albumen (white of egg) ; no precipitate occurs. Metapliosphoric acid, it will be remembered, gives a white precipitate with albumen.
id .y Google
QUESTIONS AND BXBECISRS.
580. What are the sources of laetjc acid ?
581. How is lactic acid usually prepared ?
582. Name some of the plants in which maiic acid is found,
583. Whence is meconic acid derived?
584. By what process may meconic acid be isolated ?
585. Which is the best test for the meconic radical?
586. Distinguish nieconafes from sulphocyanntes,
587. Give the mode of mftiinfacture of hypophosphites.
588. How is the phoaphoretted hydrogen prepared ?
589. By what ready method may metaphosphoric acid be obtained for experimental purposes ?
590. Name the testa for metaphosphates,
591. How may meta- or pyro-phosphoric acid be converted into orthophosphorio acid?
592. Describe the preparation of phosphorous acid.
593. State the relations which the acids of phospiii.rus bear to each other.
594. How are pyrophosphates prepared ?
595. Offer two views of the constitution of pyrophosphates.
596. Define, by formnlce, metaphosphates, pyropliosphates, ortlio- phQsphates, phosphites, and bypophwphites.
597. Mention Qie tests by which meta., pyro-, and orthophosphates are analytically distinguished.
598. Name the reactions by which hypophosphites and phosphites are detected.
Silicic Acid (H.SiOj} as d otheii Silicates. — Silicates of various kiuds are among the commonest of minerals. The ordinary sand- atones are chiefly silicates ; meerschaum is an acid silicate of mag- nesium ; the various daya are aluminium silicates ; sand, JUnt, ?uwrt%, agate, chalcedony, and opal, are silicic anhydride or aUica SiO,). Artificial silicates are familiar under the fornaa of glass and earthenware. Ooramon English window-giass is usually silicate of calcium, sodium, and alaminium ; French gloss, silicate of calcium and sodium ; Bohemian, chiefly silicate of potassium and calcium ; Euglish flint- or crystal-glasB for ornamental, table, and optical par- poses, is mainly silicate of potassium and lead. Earthenware ia mostly silicate of aluminiam (clay), with more or less of silicate of calcium, sodium, and potassium, and, in the commoner forms, iron. Tiie various kinds of porcelain (China, Sfevres, Meissen, Berlin, Eng- gliah), Wedgwoodrware, and stoneware are varieties of earthen- ware. Orucibles, hrichi, aud tiles are clay-silieatea. Mortar is es- aentially silicate of calcium. Portland, Roman, »,nA other hydraulic cenumts are silicates of calcium with more or less silicate of alumi-
Mix together a few grains of powdered flint or sand with about five or six times its weight of carbonate of sodium
id .y Google
293 SALTS OP RARER ACIDULOUS RADICALS.
and an equal quantity of carbonate of potassium, and fuse a little of the mixture on platiimm-foil in the blowpipe- flame ; the product is a kind of soluble glass. Boil the foil in water for a few minutesj filter ; to a portion add excess of hydrochloric acid, evaporate the solution to dryness, and' again boil the residue in water and acid; oxide of silicon or silica (SiOJ remains as a light, flaky, insoluble powder.
The soluble glaxs or glass liquor of trade commonly contains 10 OT 12 per cent, of soda (NaHO) to 20 or 25 per cent, of silica (SiOj).
The foregoing operation constitutes the test for silicate. By fusion with alkali the silicate is decomposed, and a soluble alkaline silicate foi-med. On addition of acid, silicic acid (H^SiO,) is set free, but remains in solution if sufficient water is present. The heat subse- quently applied eliminates water and reduces the siiicicacidtfl silica (SiOj), which is insoluble in water or acid. By the addition of hydro- chloric acid to soluble glass, and removal of the resnlting alkaline chloride and excess of hydrochloric 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 silica contained in such an aqueous solution, nearly all wafers yielding a small quantity of silica when treated as above described.
Silimureited hydrogen, or hydride of silicon (SiH^), is a sponta- neously inflammable gas formed on treating silicide of magnesium with hydrochlorie acid. It is the analogue of light carbnretted hy- drogen (CHj). A liquid chloride of silicon (SiClj) and a gaseous fluoride (SiFj) also exist.
Succinic Acid (HsO^H^OJ.— Amber (Suecinum.) is a peculiar 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 Finns now probably extinct. Heated in a retort, amber yields, first, a sour aqueous liquid contain- ing acetic acid and another characteristic body appropriately termed sucdnic acid; second, a volatile liquid known as oil of amber lOleiim Succini Rectificatiim, U. S. P.) resembling the oil yielded by most resinous substances under similar circumstances; and, third, a pitchy residue allied to asphalt. The succinic acid is a normal constituent of the amber, the acetic acid is produced during distilla- tion. Succinic acid has also been found in wormwood, in several pine-resins, and in certain animal fluids, snch as those of hydatid cysts and hydrocele. It may be obtained artificially from butyric, stearic, or margaric acid by oxidation. Tartaric, maho, and succinic acids are also convertible the one into the other.
The succinates are normal (E'-C^H^OJ and acid (E'HO.H.OJ ; a donblesuccinateofpotassium and hydrogen (KHOjH|Oj,HjC,H,0 J, HjO), analogous to the superacid oxalate, salt of sorrel, also exists.
id .y Google
SULPIIOGYANIC ACID. 2i)3
Soluble succinates give a inilky brown precipitate with neutral ferric chloride, only less voluminous than ferric beiizoate ; a white precipitate with acetate of lead, soluble in excess of either reagent ; with nitrate of silver a white precipitate after a time ; with chloride of bfirium no pre- cipitate at first, but a white one of succinate of barium on the addition of ammonia and alcohol. Succinates are distinguished from benzoates by the last-named reaction, and by not yielding a precipitate on the addition of acids ivide p. 2T1).
SurPHOoTANio Acid (HCyS) and other Sulphoctan- ATES. — Boil together sulphur and solution of pure cyanide of potassium ; solution of sulphocyanate of potassium (KCyS) is formed.
Tests. — Filter, and to a small portion of the solution add a ferric salt (PCjClg) ; a deep-blood-red solution of ferric aiilphoeyanate is formed. To a portion of the red liquid add hydrocliloric acid ; the color is not discharged fmeconate of iron, a salt of similar tint, is decomposed by hydrochloric acid). In the acid liquid place a fragment or two of zinc, sulphuretted hydrogen is evolved, and the red color disappears.' To another portion of the ferric sulphocyanate add solution of corrosive sublimate; the color is at once discharged. (Ferric meconate is unaffected by corrosive sublimate.) The ferric is the best test of the presence of a sulphocyanate ; indirectly, it is a good test of the presence of hydrocyanic acid or cyanogen.
To solution of a sulphocyanate add solution of mercuric nitrate ; mercuric sulphocyanate is precipitated as a white powder.
Pharaoh's Serpents. — Mereuvic aulphocyanftte, thoroughly washed and made up into little cones, forms the toy called Pharaoh's serpent. It readily bams when ignited, tiie chief product being a light solid matter (mellon, OjN,,, and the melam, OjHjNj), which issues from the cone in a snake-like coil of extraordinary length. The other pro- ducts are mercnric sulphide (of which part remains in the snake and part is volatilized), nitrogen, sulpbaroas and carbonic acid gases, and yapOT of metallic mercury. (For details concerning the econo- mical manufacture of snlphocyanates see Pharmaceutical Joiirnai, second series, vol. vii. p. 581, and p. 152.)
The sulj|hocyanic radical (CyS) is often termed sulphocyanogen (8cy), and i!s compounds regarded as mHphoeyamdes.
Tannic Acid or TAKiaN70„H„Oi,).~-This is a common astrin- gent constituent of plants, but ia contained in largest quantity in galis (excrescences on the oak formed by the puncture and deposited ova of an insect). English galls contain from 14 to 28 per cent, of 25*
id .y Google
204 SALTS OF RARER ACIDULOCS RADICALS.
tannic acid ; Aleppo galls ( Gcdla. B. P. and U. S. P.) from 25 to G5 per cent, (Acidum Tannidim, B. P. and U. S. V.)
Process. — "Expose powdered galls (about an ounce ia sufficient for the purpose of study) to a damp atmosphere for two or thi-ee days, and afterwards add sufficient ether to form a soft paste. Let this stand in a well-closed vessel for twenty-four hours, then, having quickly enveloped it in a linen cloth, snbmit it to strong pressure so as to separate the liquid portion, which contains the bulk of the tannin in solution. Reduce the pressed cake to powder, mix it with sufficient ether, to which one-sixteenth of its bulk of water has been added, to form again a soft paste, and press this as before. Mix the expressed liquids, and expose the mix- ture to spontaneous evaporation until, by the aid subse- quently of a little heat, it has acquired the consistence of a soft extract ; then place it on earthen plates or dishes, and dry it in a hot-air chamber at a temperature not ex- ceeding 213°."
The resulting tannic acid occurs in "pale yellow vesi- cnlar masses or thin glistening scales, with a strongly astringent taste, and an acid reaction, readily soluble in water and rectified spirit, very sparingly soluble in ether."
Medicinal Uses. — Tannic acid is very soluble in water, and in this form is usually administeretl in medicine. Its official preparations are Glycerinum Actdt Tanmci, Suppositoria Acidi Tannici, and Trochisci Acidi Tannici.
Tests. — To an aqueous solution of tannic acid add aque- ous solution of gelatine, a yellowish- white flocculent com- pouud of the two substances is precipitated. This is a good test of the presence of tannic acid.
Tanning. — Tlie above reaction also serres to explain the chemical principle involved in tanning — the operation of converting skin into leather. In that process the skin is soaked in infusion of oak-bark (§McrcM« Cortex), the tannic acid of which uniting with the gelati- nons tissaes of the skin yields a compound very well represented by the above precipitate. Other infusions and extracts besides that of oak-bark are largely used by tanners; but they appear to act too quickly, and give a harsh, hard, less durable leather. The tannic acid of these preparations is probably slightly different from that of oak-bark.
To an aqueous solution of tannic acid add a neutral so- lution of a ferric salt ; dark bluish-black tannate of iron is slowly precipitated. This is an excellent test for tiie pre- sence of tannic acid in vegetable infusions. The prccipi-
id.y Google
TAflNIC ACID — QALLIO AOID. 295
tate is the basis of nearly ail black writing-ink. Perrons salts give at first onlj' a slight reaction with tannic acid ; but the liquid gradually darkens. Characters written with this liquid become quite black in a few hours, and are very- permanent.
To an aqueous sohition of tannic acid add solution of tartar-emetic; tannate of antimony is precipitated. This reaction and that with gelatine are useful in the quantita- tive estimation of the amount of tannic acid in various substances.
Tannic acid is a glucoside; that is, like several other siibBtanccs, it jieWs glucose (grape-sugar) when boiJed with dilute sulphuric or hydrochloric a«id, the other product being gallic acid : — Os,H,50„ + 4H,0 = 0„H,,0, + 3HjC,H,05.
Catechu {Gaiecku, V. S. P., Goiechu pallidum, E. F.), Gambit, or Terra Japonica, Kino (Kino, B. P. and U. S. P.), Elm Bark ( Ulmi Cortex, B. P.), and Slippery Elm Bark ( Ulmusfulva, U.S. P.), and some other vegetable products contain a variety of tannic acid {immo4annic add) , which gives a greenish precipitate with neutral solutions of ferric salts.
Bael fruit {Betas frudws, B. P.), from the JEgle Marmdos, is said to owe its astringency to a variety of tannic acid. In India a jelly and preserve have long been made from the Mavmelos — whence the word marmalade for similar preserves. The astiingoncy of Pomegranate- root Bark (ffr<wia(tjKo*'c!s Cortex, B.P. andU. S.P.}, and Fruit (Oranati Fruetus Cortex, U.S. P.), is due to tannic acid (its anthel- mintic properties probably to a resinoid matter) ; and the same may be said of logwood [HeematoxyK Ldgnwia, B. P. and U. S. P., the color of which is due to oxidized hwmatoxylin). Rhatany-rooX, (Kramerice Radix, B. P. and U. 8. P.) contains about 40 per cent, of tannic acid, its active aatriogent prmciple ; rhubarb-root about 9 per cent. Searfierry-leaves ( Uv(b Ursi Folia, B. P. and U. S. P.) owe most of their therapeutic power to about 35 per cent, of tannic acid. (The cause of their influence on the kidneys is not yet traced.)
Gallic acid (H3C,H,0^,H,0) (Acidttm OalUcum, B. P. and U.S. P.) occurs in small quantity in oak-galls and otter vegetable substances, but is always prepared from tannic acid. Powdered galls are moistened with water and set aside in a warm place for Ave or six weeks, occasionally being remoistened; fermentation occurs, and impure gallic acid is formed. The product is treated with about three times its weight of water, boiled to dissolve the gallic acid, filtered, the solution set aside to cool, deposited gallic acid collected, drained, pressed between folds of paper to remove all mother-liquor, and, if necessary, puri- fied by recrystallization from water, or by solution in hot
id .y Google
396 SALTS or rarer acidulous radicals.
water and treatment with animal charcoal, whieli absorbs coloring-matter. On filtering and cooling, most of the acid separates in the form of fawn-colored slender acicular crystals, Gallic acid is soluble in about 100 times its weight of cold or 3 of boiling water, freely in spirit, spar- ingly in ether.
The nature of the action by which gallic acid is thus produced ia
?robably similar to that of the action of dilute aeida on tannic acid. >uring the process oxygen is absorbed and carbonic acid gas CTolved, the sugar being thus broken up or perhaps prevented from being formed.
Test. — To an aqueons solution of gallic acid add a neu- tral solution of ferric salt ; a bluish-black precipitate of gailate of iron falls, similar in appearance to tannate of iron. Ferrous salts also are blackened by gallic acid. To more of the solution add an aqueous solution of gela^ tine; no precipitate occurs. By the latter test gallic is distinguished from tannic acid.
Pyrogallic Acid {CjH.Oj). — This substance sublimes in light feathery crystals when gallic acid is heated. To an aqueous solution add a neutokl solntlon of a ferric salt ; a red color is produced. To another portion add a ferrous salt ; a deep-blue color results.
Tmt for the three acids.— To tiree separate small quantities of milk of lime in teat-tubes add, respectively tannic, gallic, and pyro- gallic acids; the first slowly tnms brown, the second more rapidly, while the pyrogallic mixture at once assumes a beautiful purplish- red color changing to brown. These reactions are highly character- istic. They are accompanied by absorption of oxygen from the air.
Use of Pyrogaiiic Acid in Oas-analysis.—A. mixture of pyro- gallic acid and solution of potash absorbs osygen with such rapidity and completeness that a strong solution of each, passed up succes- sively by a pipette into a graduated tube containing air or other gas, forms an excellent means of estimating tree osygen. The value of this method may be roughly proTod by pouring a small quantity of each solution into a phial, immediately and firmly closing its mouth with a cork, thoroughly shaking the mixture and then removing the cork under water; uie water rushes in and occupies about one-fifth of the previous volnme of air, indicating that the atmosphere con- tains one-fifth of its bulk of oxygen. The small amount of carbonic acid gas present in the air is also absorbed by the alkaline liquid ; in delicate experiments this should be removed by the alkali before the addition of pyrogallic acid,
TTric Acid (HjC^H^N^O,) and other Urates, — Acidulate 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 vessel and floating on the surface of the liquid.
id .y Google
URATES. 297
Microscopical Test. — Remove some of the floating parti- cles by a slip of glass, and examine by a powerful lena or microscope; the chief portion will be found to be in yel- lowish semitrans parent crystals, more or less square, two of the sides of which are even, and two very jagged ; but other forms are common {vide Frontispiece).
Chemical Test Collect more of the deposit, place in a
watch-glass or small white evapo rating-dish, remove adhe- rent moisture by a piece of blotting- or filter-paper, add a drop or two of strong nitric acid, and evaporate to dryness ; the residue will be red. When the dish is cold, add a drop of solution of ammonia ; a purplish-crimsou color results. The color is deepened on the additiooof a drop of solution
Notes. — Uric acid and urates of sodium, potassium, calciam, and ammomnm are common constituenta of animal excretiona. Human ui-iiie contains abont one part of urate (usually urate of sodiumj 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 nrate is also occasionally deposited before leaving the bladder, and, slowly accumulating there, (orms a common variety of urinary calculns. — —Some urates are not definitely crystalline ; but when treated with dilute nitric acid or a drop of solution of potash and then a drop or two of acetic acid, jagged microscope crystals of nric acid are usually formed. — All nrates yield the crimson color when treated as above described. — This color IS due to a definite substance, laurexid {G^^fi^ (from the murex, a sliell-fish of similar tint) ; and the test is known as tht •m.urexi'd test. The formation of mnresid is due to the action of ammonia on alloiEaM (CtH^NjOj,4HjO) and other white crystalline products of the oxidation of uric acid by nitric acid. Mnrexid is a good dye ; it may be prepared from giiano (the excrement of sea-fowl), which con- tains a W^ Quantity of urate of ammoninm. The excrement of the serpent is almost pure ammonium urate.
Uric acid and the urates will be again alluded to in connection with the subject of morbid nrine.
Valbbianio Acid or Valebio Acid (HC-H,0,) and OTUEE Valekianates. — In a test-tube place a few drops of amylic alcohol (fousel oil) with a little dilute sulphuric acid and a grain or two of red chromate of potassium, cork the tube, set aside for a few hours, and then heat the mix- ture ; valerianic acid, of characteristic valerian-like odor, is evolved.
Valerianic acid occurs naturally in valerian-root, but is usually prepared artificially, by the foregoing process, from amyiic alcohol,
id .y Google
ALTS OE EA
C,H,HO + 0, =HC,H,0, + H,0 C,H„HO + 0, = H0,H,O, + H,0.
Valerianate of Sodium (NaCjHjO,) (Sodx Valerianas, B. P. and TJ. S. P.) is prepared from the valerianic acid obtained on distilling the mixture of amj'lic alcohol (4 fl. 02s.)f sulphuric acid (6^ fl. ozs, with 10 of water), and red chromate of potasaium (9 oza. in TO of water). The mix- ture should stand for a few hours before heat is applied. 2(K,0rO„CrO,) + 8H,S0, = 2(Cr,3SO,) -f 2K,S0^ + SH^O + 30,
CsHj.HO + 0,= HCsIIjOj + H,0
2GM,,nO + 0, = CJI„CsH,Oj + 2H,0
The distillate (70 or 80 ozs.jis saturated with soda, which not only yields valerianate of sodium with the free valerianic auid, but de- composes the valerianate of amjl produced at the same time, more valerianate of sodium being formed and some amylic alcohol Bet free, according to the following equations ; —
HO,Hi,0. + NaHO = NaO^HjO, + H,0
ValerlanLc Soda. Valerian »t8 Waler.
add. of sod Urn.
CHiiO^HgOi + NaHO = NaC;H,0, + 0;,H„HO
ValBllluate SodB. Valerianate Amvlio
Q/amyl, ofsodLum. alcolinl.
From the solution of valerianate of sodium (which should be made neutral to test-paper by careful addition of soda solution) the solid white salt is obtained by eva- poration to dryness and cautious fusion of the residue. The mass obtained on cooling should he broken up and tept in a well-closed bottle. It is entirely soluble in spirit.
Other Valerianates, as valerianate of zinc {Zinci Vale- rianas, B. P.) and ferric valerianate, may be made by double decomposition of valerianate of sodinm with the sulphate or other salt of the metal the valerianate of which is desired, the new valerianate precipitating or crystalliz- ing out.
Teats. — Heated with diluted sulphuric acid, valerianates of the metals give valerianic acid, which has a highly characteristic smell. Valerianate of sodinm thus treated, and the resulting oily acid liquid purified by agitation with
id .y Google
VALERIANATES, 399
aulphnrie acid and distillation furnishes the Acidum. Vale- rianicum of the United States Pharmacopcoia. Sp. gr. 933. Dry ammonia gaa passed into valerianic acid gives white lamellar crystals of valerianate of ammonium {Ammonise Valerianas, V. S. P.).
The amylic alcohol (CjHjiHO) from which valerianates are pre- pared may contain the next lower homologne, butyh'c alcohol iO.H^O) . This, daring osidatioo, will be eonverled into butyric add (HO.H,0,), the next lower homologue of valerianic acid {HC^HgOj), and nence the various valerianates be contaminated by some outy- rates. These are detected by distillation with diluted anlphuric acid and addition of solution of acetate of copper to the distillate, which at once becomes turbid if butyric acid be present. In this reaction valerianic and butyric acids are produced by double de- composition of the valerianate and butyrate by the sulphuric acid, and distil over on the application of heat. On the addition of ace- tate of copper (Ou2CjHsO,) butyrate of copper {Cu20^H,0„ H,0) is formed, and, being almost msolaole in water, is at once precipitated, or remains suspended, giving a blnish-white opalescent liquid. Valerianate of copper (Ou2C^H50j} 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 grccn- ish-blue hydrous crystalline valerianate of copper (Larocque and Huralt).
QUESTIONS AND EXEBOISES.
599. What is the constitution of nitrites ?
600. Mention a test for nitrites in potable waters.
601. Which nitrite is official?
602. Give the names of some natural and artificial silicates.
603. What is " soluble glass ? "
604. Distinguish between silica and silicic acid.
605. How are silicates detected?
606. What is the quantivalence of silicon ?
607. Mention the sources, formulse, and analytical reactions of succinates,
608. State the mode of manufacture and teste of sulphocyanates.
609. What proportion of tannic acid is contained in galls ?
610. DescriBe the official process for the preparation of Tannic
611. Explain the chemistry of " tanning."
612. Enumerate the tests for tannic acid.
613- What is the assumed constitution of tannic acid?
614. Mention other official substances whose astringency is due to tannic acid.
615. How is gallic acid prepared?
616. By what reaction is gallic distinguished from tannic acid ?
617. Mention the characteristic properties of pyrogallic acid,
618. Explain tlie uinresid test for uric acid.
id .y Google
RADICALS
619. DeBcribe Uie artificial preparation of valerianic acid and other valerianates, giving diagrams or equations.
620. What is the formula of valerianic acid?
621. How are butyratea delected in presence of valerianates ?
DETECTION OE THE ACIDULOUS RADICALS OP SALTS iiOLUBLE IN WATER.
Analytical operations may now be resumed, the detection of acid- ulous radicals being practised for two or three days, and then full analyses made, both (or basylous and acidulous radicals. To this end a few compounds of stated metals (potassium, sodium, or ammo- nium) should be placed in the hands of the practical student for examination according to the following paragraphs and Tables. Mixtures in which both basylous and acidulous radicals may be sought should then be analyzed.
In examining salts soluble in water, and concerning which no gene- ral infoiTuation is obtainable, search must fii^t be made for any basy- lous radicals by the appropriate methods [vide pages 178 or 210), Certain metals having Men thus detected, a little reflection on the character of their salts will at once indicate what acidulons radicals may be, and what cannot be, present. Thus, for instance, if the sub- stance under examination is freely soluble iu water, and lead is 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 lifeely to be acetate than nitrate of lead, for two reasons : the former is more soluble than the latter, and is by far the commoner salt of the two. Medical and pharmaceutical students have probably, in dispensing, already learned much concern- ing the solubility of salts, and whether a salt is rarely employed or in common use. And although but little dependence 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 magnesinm have been found associatSed with the sulphuric, nitric, and hydrochloric radicals, and we are asked how we suppose these bodies may exist in the mixture, it is far more in accordance with common sense to sugg^t that sal- ammoniac, nitre, and Epsom salt were originally mixed togeiher than to suppose any other possible combination. Such appeals to expe- rience regarding the solubility or raritiy of salts cannot be made by any one not previously acquainted, or insufficiently acquainted, with the characters of salts ; in Buch cases the relation of a salt to water and acids can be ascertained by referring to the following Table (p. 302) of the solubility or insolubility of about five hundred of the common or rarer salts met with in chemical operations.
The opposite course to the above (namely, to ascertain what acidu- lous radicals are present in a mixture, and then to appeal to expe- rience to tell what bawylous radicals may be and what cannot be
id .y Google
DETECTION OF ACIDULOUS RADICALS. 301
present) is impracticable; for acidulons radicals cannot be separated out, one al^er the other, from one and the same quantity of substance by a similar treatment to that already given for basylous radicals. Indeed such a sifting of acidulous radicals could scarcely be accom- plished at all, or only by a vast deal of labor. The basylous radicals must, therefore, be first detected.
Even when the basylous radicals have been found, the acidulous radicals which may be present must be sought for singly, tbe only additional aid which can be brought in being the action of sulphuric acid, a barium salt, a calcium salt, nitrate of silver, and ferric chlo- ride on separate Bmall portions of the solution under examination, as detailed la the second of the following Tables.
Commence the analysis of an aqaeoua solution of a salt oi' salts, the basylous radicals in which are known, by writing out a list of the acidulous radicals which may be, or, if more convenient, of those which cannot be present. To this end consult the following Table (p. 302) 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. The acidulous part of the name is given in the top line of the Table. All the names are in alphabetical order, for facility of reference.
Some of fie salts marked aa insoluble in water are soluble in aqueous solutions of soluble salts, a few formina; soluble double salts. To characterize salts as soluble, slightly soluble, or insoluble, 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 solubUity of every salt.
If only one, two, 'or perhaps three given acidulous radicals can be in the liquid, 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 solutions, rendered neutral if necessary hy ammonia, into five test4ubes, and add respectively sulphuric acid, nitrate or chloride of ba- rium, chloride of calcium, nitrate of silver, and ferric chloiHde ; then consult the Table on page 303, in order to correctly interpret the effects these reagents may have pro- duced.
id .y Google
302 DETECTION OF ACIDULOUS RADICALS
|
■ewiusj, |
a» s.s.B.!i..s.^_».s,__i.,«„«_»ii |
|
|
■9,;Hdine |
_•> •>i«5,„..t_„«i..^£«.«„«..„„!. |
|
|
-spiiidiag |
„«„«„„s. «._»„„»_, |
|
|
■ei^ilding |
«„__««i»»»«»..„«««S... »&»»»_» |
|
|
■eiBqdsoiid |
— - "-«■ |
|
|
1 1 |
-.Pl.0 |
— "— 1 »„»„„»„ |
|
""""^ |
„»a «„„!.5,.. ...„.«_„„ |
|
|
„,_„„«.«.«.»..»«. »««»«»^.»»» |
||
|
-H!..I |
||
|
■9)S.tp:(H |
||
|
n |
epmiiio |
..„_....»_„„. — .,„:..._.,„„«..>.„ |
|
S |
'-"'» |
„«„„_..»„... «...._.«t__-»„»„_-« |
|
■.,..„ |
Si-^&l. 5. S.«»«»«.-S.»-. -«.."-".. ..-S. |
|
|
e |
,,„,3 |
„^„„»».„»„«»»S,»».»„«««„»««.,m |
|
'i |
,„.„.» |
-•- — - ..»„»..^„„ |
|
..„..,„ |
„»„„....„_ > «„. |
|
|
s |
aisjneajv |
-»— •-". — |
|
1 |
,«..,- |
«,„«.. „»«„«»»^„«„,!,«^„5.,„,o,= c.,^ |
|
■»! |
||
|
1 g. . a i i s , S . a 5 . . . . a . llllllliiiLilPiilisllii. |
Hoa,d, Google
DETECTTOK OF ACIDULOISS RALTCALS. 303
|
11 It |
ill |
|
|
i |
1 i' |
ILItll SS3S£»i |
|
s t i |
flMl iiiiiiiiriifi ililiillPiSilfll |
|
|
ll If |
iJli!l!itiiaiH a o5 5 o ° |
|
|
S2 |
1 Is ji |
. JiSi jiljljljpaiiiii |
|
1^ |
1=111 ?! i': iil^l II li- i-.|f5lllillliSlll |
Hosled^y Google
ETECTTON OF ACIDULOUS EAUICA
The first point of valne to be noticed m connection witii this Table is one of a negative character; namely, if either of the re- agents gives DO reaction it is self-evident that the salts which it decomposes with product! f p *p't te m t h h t Th again, if the action of o f th ts d t tl b ce
of certain acidulona radical th dil anthpretttd
by the other reagents ; th f th t f Iph dp t
to the absence f Iph d Iph fe ca b tes j d d
acetates, these s It m b t k t f th th li t d th examination of Vq tp ptteb f jilEd 0 f
the barium prec p t t is 1 bl hyd H d d fh 1
cinni precipitate in t d th Iph t 1 te
he present. Ob g th d th r ts f d ff wh h
will be seen on c fil d th ghtt 1 fl ( d m ml mg
the (acts suggest d bj kn 1 d"^ f h t basyl d 1
present, one acid 1 us rad 1 ft r the other may be struck off as absent or present I g ly e or two as the objects of special experiment. Ai g th hi i d fBcultiM to be encountered will be the separation fr atl th f chlorides, bromides, iodides, and
cyanides, or of tartrates from citrates, and confirmatory testa of the presence of certain compounds. These may all be surmounted on referring back to the reactions of the varions radicals, as described under tSeir hydrogen salts, the acids.
The rarer acidulous radicals will very seldom be met with. Benzoales, hippurates (which give benzoic acid), ht/pockloritea, hyposulphites, nitrites, and valerianates show themselves under the sulphuric treatment. Ferrooyanides, ferridcyimidea, meconates, SJiccinaies, snlpkocyanates, tannates, and gallaies apjwar among the salts whose presence is indicated by ferric chloride; formialea, hvpophosphites, molates, and others by nitrate of silver. 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 ehromiam and arsenicum have been detected among the basy- lous radicals, those elements maybe present in the form of cftrowaJes, arseniates, and areenites, yielding with chloride of barium yellow chromate of barium and white arseniate and arsenite of barium, and with nitrate of silver red chromate, brown arseniat*, and yellow arsenite of silver.
QUESTIONS AND EXERCISES.
622. In analyzing an aqueous solution of salts, for which radicals would you first search, the basjlona or the acidulous t and why ?
623. In an aqneons solution there have been found magnesinm (Mg) and potassium (K), with the snlphnrie radical (80.) and iodine (I) ; state the nature of the salts which were originally dis-
id.y Google
DETECTION OF ACIDULOUS RADICALS. 305
solved in the water, and mention tlie principles which guide you to the conclusions.
624. Give a sketch of the method by which to analyze a neutral or only faintly acid aqueous liquid for the acidulous radicals of salts. In what stage of the process would the following salts be detected !
a. Carbonates and Sulphates.
b. Oxalates.
c. Tartrates and Nitrates.
d. Acetates and Sulphites,
e. iBromides and Cyanides. /. Borates,
a. Iodides and Phosphates.
h- Chlorates, Oxalates, and Acetates.
i. Chlorides and Iodides.
i'. Sulphites.
k. Sulphides, Carbonates, and Nitrates.
I. Citrates and Sulphates.
625. Nitrate of silver gives no precipitate in an aqueous solution ; what salts may be present?
626. Chloride of barium gives no precipitates in a neutral solu- tion, but nitrate of silver a white ; what acidulous radicals are indi- cated ?
627. Ferric chloride produces a deep red color in a solution, chloride of calcium yielding no precipitate ; what salts may be present, and how might they be distiii^ished from each other ?
628. Fen'ic chloride gives a black precipitate in a solution iu which sulphuric acid develops no odor ; to what is the effect due ?
ANALYSIS OF SALTS,
SINGLE OR MIXED, SOLUBLE OR INSOLUBLE.
Thus far all material substances, especially those of phar tical interest, have been regarded as being definite compounds, and fls having certain well-defined parts, termed, for convenience, basy- lous and acidulons respectively: moreover attention has been de- signedly restricted to those definite compounds which are soluble in water. But there are many substances having no definite or known composition ; and of those having definite composition there are many having no definite or ascertained parts. Again, of those having definite composition, and whose constitution admits of the entertainment of theory, there are many insoluble in waf«r.
Chemical substances of whose composition or constitution little or nothing is at present known, are chiefly of animal and vegetable origin, and figure in tables of analysis under the convenient collec- tive title of " extractive matter;" they arc not of immediate impor- tance, and may be omitted.
2fi*
id .y Google
306 GENERAL QUALITATIVE ANALYSIS.
Of Bubstances which are definite in composition, but whose parta or radicals, if they have any, are unknown or imperfectly known, there are only a few (such as the alkaloids, amylaceous and saccha- rine matters, the glucosides, alcoholic bodies, albumenoid, fatty, resinoid,and colorific substances) which have any considerable amonnt of pharmaeentical interest ; these will be noticed subsequently.
Definite compounds most frequently preseut themselves; and of these by far the larger proportion (namely, the salts soluble in water) have already been flilly studied. There remain, however, many salts which are insoluble in water, bnt which must be brought hito a state of solution before they can be effectively studied from an analytical, pharmaceutical, or a physiological point of view. 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 analyti- cal schemes than those which have been given, will in only one or two cases increase the difficulty of the analysis of a precipitate pro- duced by a group-reagent, bat will give roundness, completeness, and a practical bearmg to the reader's analytical knowledge. Such a procedure will at the same time bring into notice the methods by which substances insoluble in water are manipnlafed for pharmaceu- tical purposes, or made available for use as food by plants, or aa food and medicine by man and animals g^ -"'■
Pi-diimnaTy Examinaiion of Solid [chiefly mineral) Salts
Before attempting to di^olve a salt for analysis, its appearance and other physical properties should be noted, and the influence of heat and strong sulphuric acid be ascertained. If theopeiatniknons how to interpret what is thus observed, and to what extent to place confidence in the observations, he may more certainly obtain a high degree of precision in analysis, and will always gain some valuable negative information. But if he has only slight experience of the appearance and general properties of bodies, or has the habit of turn- ing what should be inferences from tentative process^ into foregone conclusions, he should omit the preliminary examination altogether, or only follow it out under the ^idance ot a judicions tutor ; for it is impracticable here to do more than hint at the ri^ulfs which may be obtained by such an examination, or to so adapt descriptions as to prevent a studentfromailowingunnecessaryweight to preconceived ideas.
Whatever be the course pursued, short memoranda describing re- sults should invariably be entered in the note-book.
1. Examine the physical characters of the salt in various ways, but never, or only rarely, by the palate, on account of the danger to be apprehended.
If the salt is white, colored substances cannot be present ; if co- lored, the tint may indicate the nature of the substance or of one of its constituents, supposing that the learner is ah'eady acquainted with the colors of salts. Closer observation, aided perhaps by a
id, Google
PRELTMINAKY EXAMINATIONS. 307
lens, may reveal the occurrence, in a pulveriileat mixture, of small crystals or pieces of a single substance ; these should be picked out by a, needle and examined separately. The body may present an un- doubted metallic appearance, in which case only the metals existing under ordinary atmospheric conditions need be sought. Peculiarity in smell reveals the presence of ammonia, hydrocyanic aeid, hydrosul- phuric acid, &c. Between the fingers a substance is, perhaps, hard, soft, or ^itty ; consequent inferences follow. Or the matter may be heavy, like the salts of barium or lead ; or light, like tlie carboaatss and hydrates of magnesium.
3. Place a grain or two of the salt in a small dry test- tube or in a piece of ordinary tubing, closed at one end, and heat it, at first gently, then more strongly, and finally, if necessary, by the blowpipe.
Oases or vapors of characteristic appearance or odor may be evolved; such as iodine, nitrous fumes, sulphurous, hydrocyanic, or ammoniacal gases. Much ateam given by a dry substance indicates either hydrates or salts containing water of crystallization. (A small quantity of interstitial moisture often causes heated crj'stalline substance to decrepitate — from deerepo, to crackle — that is, break up with slight explosive violence, owin^ to the expansive force of the steam suddenly generated.) A sublimate may be obtained, due to salts of mercury or arsenioum, to oxalic or benzoic acid, or to 6«1. phur free or as a snlphide— a salt wholly volatile containing such substances only. The compound may blacken, pointing to the pre- sence of organic matter — which, in common definite salts, will proba- bly be in the form of acetates, tartrates, and citrates, or as common salts of the alkaloids morphia, qninia, strychnia, or as starch, sugar, salicin, or in other definite or indefinite forms common in pharmacy and for which tests will be given in subsequent pa^s. If no charring occurs, the important fact that no organic matter is present is estab- lished. The residue may change color from presence or development of oxide of zinc, oxide of iron, &o., or melt from the preseace of a fusible salt and absence of any large proportion of inlnsibie salt, or be unaltered, showing the absence of any large amount of such sub- stances.
3. Place a grain or two of the salt in a test-tube, add a drop or two of strong sulphuric acid, cautiously smelling 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.
Iodine, bromine, and nitrons or chlorinoid fumes will reveal them- selves by their color, indicating the presence of iodides, bromides, iodates, bromates, nitrates, and chlorates. The evolation of a co- lorless gas fuming on coming into contact with air, and having an irrifating odor, points te chlorides, fluorides, or nitrates. Gaseous products li:ivirig a greenish color and odor of chlorine indicate chlo-
id.y Google
308 GENERAL QUAtlTATTVE ANALYSIS.
rates, hypochlorites, or chlorides mixed with other snbatancea. Slight sharp eiploaions betoken chlorates. Evolution of colorless gas may proceed from cyanides, acetates, snlphidea, sulphites, carbonates, or oxalates. Charring will be due to citrates, tartrates, or other organic matter. If none of these effects are produced, moat of the bodies are absent or only present in minute quantity. The substances ap- parently unaffected by the treatment are metallic oxides, borates, sulphates, and phosphates.
4. Exposure of the substance to the blowpipe- flame, on platinum wire with or without a bead of borax or of mi- erocosmio salt {phosphate of sodium, ammonium, and hydrogen, NaAinHPO^) — on platinum foil in a porcelain crucible, or on a crucible lid with or without carbonate of sodium — on charcoal, alone or in conjunction with car- bonate of sodium, cyanideof potassium, or nitrate of cobalt, will sometimes yield important information, especiallj' to one who has devoted mucli attention to reactions produ- cible by the blowpipe-flame. The interior portions of the flame consist of hydrocarbon gases heated to a tempera- ture at which they combine with oxygen with great avidity, abstracting that element from metallic oxides or other oxidized substance which may be brought within their in- fluence ; the exterior portions, on the other hand, contain excess of heated oxygen ; the former is the reducing, the latter the oxidizing part of the flame. The medical or pliai'maceutical student, however, will seldom have time to work out this subject to an extent sufficient to malte it a trustworthy guide in analysis, (See Plattner and Muspratt "On the Use of the Blowpipe," and a chapter in Gallo- way's "Manual of Qualitative Analysis.")
Methods of dissolving and analysing single or -mixed solid
Saving submitted the substance to preliminary examination, proceed to dissolve ond wry^yxe 5y the foUowing Titethods. These operations consiaf in treating a substance well powdered, contecu- tively with cold or hot teaier, hydrochloric acid, nitric acid, nitro- hydrochloric acid, or fusion with aikaiine carbonates and solu- tton of ilte product tn water and acid. MesitltiTt^ liquids are anaiyned in the moMier already described, or by shghily modified processes as detailed in tlie following paragraphs.
Solution in Water. — Boil a grain or two of the salt pre- sented 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 oi' more of water, and jiroceerf wilh
id .y Google
METHODS OF EFTEOriNG SOrUTION. 309
Ike analysis in ike usual way, testing first for the basy- lous radical or radicals by the proper group-reagents (HCI, H,8, AmHS, Am^CO,, Am,HPO,), pp. 181 or 212, and then for the acidulous radical or radicals, directly or by aid of the prescribed reagents (H^SO,, BaCL,, CaCl,, AgNO„, Fe,Cl„), p. 303.
If the salt is not wholly dissolved by the water, ascer- tain whether or not any has entered into solution, by filtering, if necessary, and evaporating a drop or two of the clear liquid to dryness on platinum foil ; the presence or absence of a residne gives the information sought. If anything is dissolved, prepare a sufficient quantity of solution for analysis and proceed as usual, reserving the insoluble portion of the mixture, after thoroughly exhaust- ing with water, for subsequent treatment by 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 efiervescence (due to the presence of sulphides, sulphites, carbonates, or cyanides) occurs, and proceed with the analysis as before, except that the first step, the addition of hydrochloric acid, may be omitted.
The analysis of this solution will in moat respects be simpler than that of an aqueous solution, inasmach 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, carbonatra, cyanides, oxides, and hy- drates; and certain borates, oxalates, phosphates, tartrates, and citrates (possibly silicates and fluorides), which are insoluble in water but aolnble in acids without apparent decomposition. The first four — sulphides, sulphites, carbonates, and cyanides — will have revealed themselves by tne oecnrrenee of effervescence during solu- tion ; and the presence of oxides and hydrates may often be inferred bj the absence of compatible acidulous radicals. The borates, oxa- lates, phosphates, tartrates, and citrates alluded to will be reprecipi- tated in the general analysis as soon as the acid of the solution is neutralized; that is, will come down in their original state when ammonia and snlphydrate of ammonium are added in the usual course. Of these precipitates, only the oxalate of calcium and the
Csphates of calcium and magnesium need occupy attention now; oxalate and phosphate of barium seldom or never occur, and the borates, tartrates, and citrates met with in medicine or in general analysis are all soluble in water. These phosphates and osalates, then, will be precipitated in the course of analysis along with iron,
id .y Google
310
AL QUALITATIVE ANALYSIS.
their presenM not interfering with the detection of any other metal. If, from the nnusual light color of th^ ferric precipitate, phosphates and oxalates are suspected, the precipitate is treated according to the following Table (reference to which should be inserted in the Table for metals, nnder Fe, pp. 181 and 212).
PRECIPITATE Oe PHOSPHATES, OXALATES, AND FEREIO
3 HOI, add citric acid, then NH^HO, and filter.
Add HO and
K.Fcy Blue ppt.
Precipitate.
Ca^aPOj, CaC,0„ Mg,2P0,.
Boil in acetic acid and filter.
Insoiuble White.
Filtrate
Ca,2P0„ Mjf,2P0,
Add Am^OjO^, stir, filter.
Precipitate
fvhite, indicating
Ca32PO,.
Filtrate, Add AmHO. White ppt. MgNHjFO,.
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 alkaline acetate, ferric chloride, and subsequent ebullition, as described under "Phosphoric Acid" (p. 298), and that dry oxalates are converted into carbonates by heat, as mentioned nnder " Oxalic Acid" (p. 287).
Certain arseniates and arsenites, insoluble in water bnt soluble in hydrochloric acid, may accompany the above phosphates and oxalates if from any cause hydrosulphuric acid gas has not been previously passed through the solution, or passed for an insnfBeient length of
If the substance insoluble in water does not wholly dis- solve in hydrochloric acid, ascertain if any has entered into solution, by filtering, if necessary, and evaporating a drop of the clear Ii<niid to dryness on platinum foil ; the pre- sence or absence of a residue gives the information sought. If anything is dissolved, prepare a sufficient quantity of solution for analysis, and proceed as usual, reserving the insoluble portion of the mixture, after thoroughly exhaust- ing with hydrochloric acid and well washing with water, for the following treatment by nitric acid.
id .y Google
METUODB OF EFIECTINO SOLUTION. 311
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 those 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 solution can contain only very few substances; for neatly all salts soluble in nitric acid are also soluble in hydrocbloric acid, and therefore will have been previously removed. Some of the metals, however {Ag, Cn, Hg, Pb, Bi), aa well aa amalgams and alloys, un- affected or scarcely affected bybyclrocbloricacid, are readily attacketl and dissolved by nitric acid. Many of the sulphides, also insoluble ill hydrochloric acid, are dissolved by nitric acid, usually with sepa- ration of sulphur. Calomel is converted, by long boihng with nitric acid, into mercuric chloride and nitrate. The nitrates here produced are soluble in water.
This nitric solution, as well as the hydrochloric and aqueous solu- tions, should be examined separately. Apparently time would be saved by mixing the three solutious together and making one analysis. But the object of the analyst is to separate every radical from every other; and when this baa been partially accomplished by solveuts, it would be unwise to again mis and separate a second time. MorO" over, solvents often do what the chemical reagents cannot — namely, separate suits itom each other. This is important, inasmuch as the end to be obtained in analysis is not only an enumeration of the radicals present, bat a statement of the actual condition in which they are present; the analyst must, if possible, state of what salts a given mixture waa originally formed— how the basylous and acidulous radicals were originally disMbuted. In attempting this, much must be left to theoretical considerations ; bat a process by which the salts themselves are separated is of trustworthy practical assistance; hence the chief advantage of analyzing separately the solutions re- sulting from the action of water and acids on a solid sobstance.
Solviion in NitroSydroahlaric Acid. — If the salt or any part of a mixture of salts is insoluble in water, hydrochlo- ric acid, and nitric acid, digest it in nitro-hydrochloric acid, boiling if necessary; evaporate to remove excess of acid, dilute, and proceed as before.
Sulphide of mercury and substances only slowly attacked by hydro, chloric or nitric acid, as, for example, caiomel and ignited ferric oxide, are sufBciently altered by the free chlorine of aqua regia to become soluble.
If the substance is insoluble in water and adds, it is one or more of the following substances : Sand and certain silicates, such as pipeclay and other clays ; fluor spar ; cryolite (3NaF, AlFJ ; sulphates of barium, strontium, and
id .y Google
312 GENERAL QUALITATIVE ANALYSIS.
possibly calcium; tinstone; glass; felspar (double silicate of aluminium and other metals) ; chloride of silver ; sul- phate of lead. It may also be or contain carbon or car- bonaceous matter, in which case it is black and combustible, burning entirely or partially away when heated in the air — or be or contain sulphur, in which case sulphurous gas is evolved, detected by its odor, when the substance is exposed to heat. For the other substances proceed accord- ing to the following (Bloxam's) method : —
Four or five grains of the substance are intimately mixed with twice the quantity of dried carbonate of sodium, and this mixture well rubbed in a mortar with five times its weight of deflagrating jiux (1 of finely powdered charcoal to 6 of nitre). The resulting powder is placed in a thin porcelain dish, or crucible, or clean iron tray, and a lighted match applied to the centre of the heap. Deflagration ensues, aud decomposition of the various substances occurs, the acidulous radicals going to the alkali-metals to form salts soluble in water, the basylous radicals being simultaneously converted into carbonates or oxides. The mass is boiled in water for a few minutes, the mixture fil- tered, and the residue well washed. The filtrate may then be examined foi' acidulous radicals and aluminium, and the residue dissolved in dilute hydrochloric acid and analyzed by the ordinary method.
The only substance which resists this treatment is cirome-iron-ore.
To detect alltali ia felspar, glaas, or cryolite, Bloxam recommends deflagration of the powdered mineral with one part of sniphnr and six of nitrate of barium. The mass is boiled in water, the mixtnre filtered, hydrate and carbonate of ammonium added to remove barium, the mixture again filtered, and the filtrate evaporated and examined for alkalies by the naual process.
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.
The method of analysis in the case of solid bodies has just been described (pp. 306-312).
In the case of liquids, the solvents as well as the dis- solved matters claim attention. A few drops are evapo-
id.y Google
OAS ANALYSIS — SPECTRAL ANALYSIS. 313
rated to dryness on platinum foil to ascertain if solid mat- ter of any kind is present ; tlie liquid is tested by 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 a cork, and some of the distilled liquid collected and examined ; fioally, the usual group-reagents for the several i>asylous and acidulous radicals are con- secutively 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, a«ids, alcohol, ether, fixed oils, and essential oils, or to miss the substances which these menstma may hold in solotion. He mnst not, however, suppose that he will always be able to qualitatively analyze, saj, a bottle of medicine ; for the various infusions, decoc- tions, tinctures, wines, sjrupa, liniments, confections, extracts, pili- masses, and powders contain vegetable matters, most of which at
E resent are quite beyond the reach of the analyst. Neither the ighest skill in analysis nor the largest amount of experience con- cerning the odor, appearance, taste, and uses of drugs is sufScient for the detection of all these vegetable matters. Skill and expe- rience combined, however, will do much, and in most cases even so dJfBcult a task as the one just mentioned be accomplished with reasonable success. Qualitative analysis alone will not enable the experimenter to produce a mixture of substances similar to that analyzed ; to Ibis end recourse must be had to quantitative analysis, a subject reserved for subsequent consideration.
Gas-analysis, or Eudtometry (from tiSwi, eudia, calm air, and pifpoy, tnetron, a measure, in aUusion to the eudiometer, an instru- ment used in measuring the proportion and, as the early chemists thought, the salubrity of the gases of the airj, is a branch of experi- mental investigation, chiefly of a quantitative character, concern- ing which information must be sought in other treatises. The analy- sis of atmospheric air from various localities, coal-gas, and gases obtained in chemical researches, involves operations whieli are scarcely within the sphere of Chemistry applied to Medicine. Beyond the recognition, therefore, of oxygen, nydrogea, nitrogen, carbonic, sul- phurous, and hydrosulphuric acid gases, the experimental considera- tion of the chemistry of gaseous bodies may be omitted. Their study, however, should not be neglected, as existing conceptions of the constitution of chemical substances are largely dependent on the observed relations of the volumes of gaseous compounds to their elements. The best work on this subject is a small book by Hof- mann, ' Introduction to Modem Chemistry.'
Spectral Analysis. — It may be as well to state here that the pre- liminary and final examinations of minute quantities of solid matter may, in certain cases, profitably include their exposure to a tempera- ture at which they emit light, the flame being physically analyzed 27
id .y Google
314 GENERAL QUALITATIVE ANALYSIS.
by a spectroscope. A spectroscope consists essentially of a prism to decompose a ray of light into its constituent colors, with tnbes und lenses to collect and transmit the ray or rays to the eye of an observer. The material to be examined is placed on the end of a platinum wire, which is then bronght within the edge of a spirit-lamp or other smokeless flamo ; volatiliaation, attended usually in the case of a compound by decompMitiou, at once ocKura, and the whole flame is tinged with a characteristic line. A flat ribbon of rays is next cut off by bringing near to the flame a brass tabe, the cap of which is pierced by a narrow slit At the other end of the tube, at focal dis- tance for parallel rays, is a lens, through which the ribbon of light passes to a prism ; the prism decomposes the ribbon, spreading out its conafitnent colors lifce a partially opened fan, and the spectrum thus produced is then examioed by help of a telescope attaohed by a movable joint to the stand which carries the prism and object- tube. Sodium componuds, under these circumstances, give yellow light only, indicated by a double band of light in a position corres- ponding to the yellow part of an ordinary solar spectrum. The f potassium spectrum is mainly composed of a red and violet band ; ithiumacrimson, andat very hig-h temperatures a blue band. Most of the other elements give equally characteristic spectra.
QUESTIONS AND EXERCISES.
629. Describe the preliminary treatment to wliich a salt may be subjected prior to systematic analysis.
630. Mention substances which might be recognized by smell.
631. Which classes of salts aje heavy, and which light?
632. Name some bodies detectable by their color.
633- What inference may be drawn from the appearance of steam when dry substances are heated !
634. Why do certain crystals decrepitate ?
635, If a powder sublimes on being heated, to what classes of
637. No diange occurring by heat, which subatancM cannot be present !
638. Give examples of salts which are identified by their reaction with strong sulphuric acid ; by their comportment in the blowpipe- flame, with or without boras or microcosmic salt.
639. What are the solvents usually employed in endeavoring to obtain a substance in a state of solution, and what is the order of tUeir application?
640, Name a few salts which may be present in an aqueous solu-
641, Mention some common compounds insoluble in water, but soluble in hydrochloric acid !
642, What substances are attacked only by nitric acid or nitro- hydrochloric acid ?
id .y Google
VEGETABLE AND ANIHAL SliBSTANCKS. 315
643. Sketch out a mctiiod for tlie eom[)lete analysis of a liquid Baspected to be an aqaeoiis solution of neutral salts.
644. How can earthy pliosphates and oxalates with ferric oxide be separated from each other ?
645. By what process may substaticea insoluble in water or acids be analyzed ?
646. How are different solventB recognized ?
647. By what methods would you attempt the analysis of a bottle of medicine ?
648. Give a short sketch of spectral analysis.
CHEMISTBY OF CERTAIN SUBSTANCES
OF VEGETABLE AND ANIMAL
ORIGIN.
Except alcohol and a few aci^s, the eomfiounds which have hitherto engaged notice have been of mineral origin. But the two other kingdoms of nature, the animal and vegetable, ftirnish a large num- ber of medicinal substances. These, indeed, when discovered, were E reducible only by highly organized living structures, and were ence termed organic compounds.*
A few of these eonipoundfl, of common occurrence in pharmacy and possessing prominent characteristics, may now occupy attention ; reactions of the alkaloids and some other principles may bo per- formed, and the methods of examining morbid n-ine be experimentally studied. There will then remain certain galenical, as distinguifihed from chemical, substancra, solid and liquid, which can only be fairly regarded from a pharmacist's point of view, and a still larger num- ' ber, doubtless, not yet brought within the grasp of the ohemiBt, and of which, therefore, we must at present be content to remain in igno- rance. An opportunity, however, will be afforded of noticing the effect of a mixture of definite and indefinite organic matter, such as a vomit or the coutfints of a stomach, in masking or preventing the reaction by which mineral and vegetable poisons are detected.
ALKALOIDS.
Constitiiiion of Alkaloids or Organic Bases.
The alkaloids, or al)(ali-like (ilSoi, eidoa, likenesa) bodies have
many analogies with ammonia. Their constitution is not yet known;
* Organic, from cfyatin, organon, an organ. A large number of organic compounds can now be obtained artiflolally — without the aid of a living organism ; liunce the dJBlinclion furmurly drawn between organic and inorganic c em ponnds, organic and inorgania chemistry, ia fast breaking down.
id, Google
816 TH£ ALKALOIDS.
but they are probably derivative of a single molecule of a (NHjj, or of double, triple, or quadruple molecules (NjH^. Njilj, NjHjj). A large number of artificial alkaloids or organic bases having such a constitution have already been formed. Those are termed amines, and are primary, secondary, and tertiary according as one, two, or three atflms of nydro^n in ammonia {the tri-hydro- gen amine) have been displaced by radicals, as seen in the following general formnlte (E=any univalent radical. Vide Index, "Alcohol radicals") —
El El El
hIn eIn r[N;
H j IT J E )
or the following examples —
C,H.) C,H 1 C,H,1
II I N L' H, y N 0,H, \ N.
H j H 1 O.-rA
Etli;l amine Siethylamine TrielliylslDiaa
or ethjIlB. or dl»tli jlU or trletbylla.
The three classes have also been termed amidogen-, imidogen-, and nitrile-bases. Propylamine or tritylia (t'jHiHHN) is a volatile oil, one of the products resulting from the destructive dKtillation of bones and other animal matters.
The displacing radicals may be similar or diifevent ; and while the radical displacing one atom of hydrogen is keeping its place, any of the mauy known radicals may occupy the position of one or both of the other atoms of hydrogen. Thus, for example, we have methyl- ethyl-amyl-amine_(CH,C350iHiiN, or MeBtiyN), a colorless, oi!y
'd from one molecule of ammonia are o molecules, diamines ; from three, tria-
E) E,) E,) EJ
B ^ N R, > K Bj > N, E, V N.
E J E, ] E, ] RJ
In these amines, any bivalent, trivalent, or quadrivalent radical may occupy the place of two, three, or foar univalent radicals.
Attempts to form artificially the natural organic bases have hith- erto fiiiled; but the primary, secondary, or tertiary character of some of them has been mdicated by the introduction or elimination of methyl, ethyl, and other radicals for hydrogen.
Note on Nommdatv/re. — The first syllables of the names of the natural alkaloids recall the name of the plant whence they were ob- tained, or some characteristic property. It is to be regretted that the last syllable is not either tne or m, instead of sometimes one and sometimes the other ; general usage seems to be in favor of the lat- ' ter, a plan that distinguishes the alkaloids fVom some other sub- stances the names of which end in ine, as chlorine, bromine, iodine, fluorine, glycerine, gelatine, &c. The names of the salts of the alka- loids are given on the assumption tliat the acid unites with the alka-
id.y Google
MOaPHIA. 311
loid without J eeom position. Tbua hydroclil orate of morphia is regarded as morphia with hydrochloric acid jast as we might assume sal-ammoniac to be ammonia (NH,) with hydrochloric acid (HOI), and name it hydrochlorate of ammonia (NH,HCI} instead of chlo- ride of ammonium (NHjCl).
Aniidotes.— la cases of poisoning bv alkaloids, emetics and the stomach-pump must be relied on rather than chemical a^nts. Astringent liquids may be administered, as tannic acid precipitates many of the alkaloids from their aqueous solation, absorption of the poison being thus possibly retarded.
MOIIPHIA, OR MOSPHINE.
Formula Oi,Hi,NOs, H^O. Molecular weight 303.
OccMi-rence. — Morphia occurs in opium (the inspissated juice of the fruit, Papavei-ts capsitlm, of the "White Foppy, /Vtpo-ue?" somji/- fervmi) as meconate of morphia.
Morphia, U. 8. P., is made by adding to infusion of opium an equal bulk of alcohol, then slight excess of ammonia, and setting aside for crystalline morphia to separate. It is purified by recrystalliaation.
/Vocess/oj- ^ydrocWoroie.— The hydroch[orate,Ci,Hi5NOj,H01, 3H,0 {Morphi(B H^droddoras. B. P.), occurs in slender white acicular crystals ; it is prepared by simply decomposing an aqueous infusion of opium with chloride of calcium, meconate of calcium and hjdrochiorate of morphia being produced. (If the infusion, which is always acid, be first nearly neutralized by the cautions addition of small quantities of a very dilute solution of ammonia, the chloride of calcium then at once causes a precipitate of meconate of calcium, which can be filtered off, leaving a colored solution of hjdrochiorate of morphia. On the large scale — vide B. P. — the details are some- what different.) The salt is partially purified by crystallization from the evaporated liquid, then by treatment of the solution of the impure hydrochlorate by animal charcoal, and lastly by pre- cipitation of die morphia from the stiil colored liquid by ammonia and resolution of the morphia in hot dilute hydrochloric acid; hy- drochlorate ot morphia separates out on cooling. The process of U. S, P. consists in neutralizing morphia by hydrochloric acid. (Morphice Murias, U. 8. P.):
Morphia Sulphas, U. S, P., by neutraliaing morphia with sulphu- ric acid.
Process for Jce(a(e.~Aeetate of morphia (C.iH^NOjCjHjO,) {Morphice Acetas, B. P. and U. S. P.) is a white pulverulent salt prepared by dissolving pore morphia in acetic acid, the morphia being prepared (B. P.) from a solution of the hydrochlorate by preoipita^ tion with ammonia. Eight' parts of hydrochlorate yield about seven of acetate.
Both the hydrochlorate and acetate of morphia are soluble in water, but the solution is not stable unless acidulated and containing alco- hol ; hence the official solutions, 4 grains in one ounce— I in 110 37*
id .y Google
3tS THE ALKALOIDS.
(L'iquor Morpkim Ilydrocldoratis, B. P., and Liquor Morphice Acetatts, B. P.), consists of three parts water and one part rec- tified spirit, a few minims per ounce of hydroelilorio or acetic acid being added. Jjiquor Jfo?pfe'<e Sidphatis, V. S. P., is a solution in water, 1 in 456. The other official preparations are Siippositoria Morphice, Trochisci Morphite, and Troekisci Morphia et Ipecac- uankcB.
Analytical Reactions.
First Analytical BeacHon. — To a minute fragment of a salt of morphia add one drop of water, and wai-m the mix- ture until the salt disaolvea, then stir the liquid with a glass rod moistened hy a strong neutral solution of per- cbloride of iron ; a dirty bine color is produced. This etfect is not observed in dilute solutions.
Second Analytical Seactton. — To a drop or two of a strong solution of a morphia salt in a test-tube add a minute frag- ment of iodic acid (HIO,, page 244) ; iodine is set free. Into the upper part of the tube insert a glass rod covered with mucilage of starch, and warm the solution ; dark-blue starch iodide is produced.
Third Analytical Beaction. — To a few drops of an aque- ous infiision of opium add a drop of nevtral solution of perchlodde of iron ; a red solution of meconate of iron is produced. Add solution of corrosive sublimate ; the color is not destroyed (as it is in the case of sulphocyanide of iron, 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 morphia (the poison itself), weconic acid being obtainable from opium only.
Other Meactions. — Add carbonate of sodium to a solu- tion of a salt of morphia ; a white precipitate of morphia falls, slowly and of a crystalline character if the solution is dilute. Collect this precipitate and moisten it with neutral solution of perctiloride of iron ; the bluish tint above referred to is produced, Add an alkali to a solu- tion of hydrochlorate or acetate of the alkaloid ; morphia is precipitated, soluble in excess of the fixed alkali, far less readily so in ammonia.— Moisten a particle of a morphia Btdt with nitric acid; an orange-red coloration is produced.rr Heat morphia on platinum foil ; it burns en- tirely fiway.
id .y Google
poMoarHiA.
:ia (C.,H„NO,).
Apomorphia (ani>, apo, from, and moipAia) is an alkaloid recently obtained from morphia by Matthiessen and Wright. It poss^sea remarkable physiological effects ; ^j of a graiu (in aqneons solution) injected under the skin, or J of a grain token mto the stomach, ia said to prodnce vomiting in trom four to ten minutes.
Process. — Hydrochlorate of morphia is hermetically sealed in a thick tube with conaitlerable excess of hydrochloric aflid, and heated to nearly 300° F. for two or three hours. The product ia purified by diluting the contents of the tube with water, precipitating with bicarbonate of aodinm, and treating the precipitate with etier or
chloroform. On shaking up the ethereal or chloroform solution
with a very small quantity of strong hydrochloric acid, the sides of the vessel become covered with crystals of the hydrochlorate of the new base. 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 ou bibulous paper or over sulphuric acid. The formula (C„H,,N05,HC1) mdicates that the new alkaloid is de- rived from morphia lay abstraction of the elements of water.
Codeia, another alkaloid of opium also, according to the same chemists, yields apomorphia by similar treatment, a reaction that would seem to indicate that codeia is methyl-morphia: —
QUESTIONS AND EXERCISES.
0„H-1 0,H-1 OH, )
n \ N, C,H, t N, 0-H, \ N.
H ) H ] CjH„ \
on,) OH.l OIL)
It \ N, OH, \ N, CH, \ N.
H J H J OHJ
651. What istieassumedconatitutionof the saita of the alkaloids? 653. Describe the treatment in cases of poisoning by alkaloids.
653. Give the process for the preparation of Hydrochlorate of Morphia. In what form does morphia occur in opium ?
654. How is Acetate of Morphia prepared ?
655. What plan is adopted for preventing the decomposition of solutions of morphia!
656. Mention the analytical reactions of morphia.
657. In addition, to the reaction of moi-phia, what test may be employed in searching for opium in a liquid or semifluid materia) !
658. How is apomorphia prepared, and what are ita properties ?
659. Describe the relation of morphis, to codeia.
id .y Google
auiNIA, OB, aUININE.
Formula Os^HsiN^Oj.aHjO. Molecular weight 318. Svurce. — Quinia and other Bimilar alkaloids exist in cinchona- bark as kin at«3. In the yellow bark ^Omc/wJite FlavcB Cortesc,B.F. and U. S. P.) quinia is almost exclusively present ; in the pale bark ( Cmchonm PaUid(B Gortex, B. P. and U. 8. P.) cinchonia ib equally characteristic; while in the red bark ( Ciwc/iowe Rubrce Goriex, B. F. and U. S. F.) these alkaloids occur in more nearly equal pro-
Process for SjtlpAorfe.— Sulphate of quinia ( Quinice Svlphas, B. P.) is prepared according to the Bvitish FharmacoijCEia by treating the yellow bark with dilute hydrochloric acid, precipitating the re- sulting solution of hydrochlorate of quinia b^ soda, and redissolving the precipitated quinia in the pro|>er proportion of hot dOnt* sulphu- ric acid. The sulphate crystallizes out on cooling in silky acicular crystals containiug two atoms of quinia (2C^Hj,N,0j), one of snl- phuric acid (H^SOJ, and seven of water of crystallization (7H,0).
In the process of the TTnited States Fharmacopraia lime is used instead of soda and the precipitated quinia is dis- solved in boiling alcohol, the latter recovered by distilla- tion, the residue quinia neutralized by diluted sulphuric acid, the solution treated with animal charcoal, filtered while hot, set aside to crystallize, and recrystallized if necessary.
Sulphate of quinia, or, more correctly, disulphate, ie only slig^htiy soluble in water ; on the addition of dilute sulphuric acid a neutral sulphate is formed which is freely soluble. The latter salt may be obtained in large rectangularprisms, having a eomposition expreesed b^ the formula C^J^fi.„ H^0„ IHfi. The oi-dinary disulphato of quinia is more soluble in alcohol or alcoholic liquids than in water; hence the Tinctiira Qtitmce, B. P., which is a solution (saturated at 550 or 6(P F.) of tie salt in tincture of orange-peel (eight trains in the ouncel. Qniniawine {Ftniiin ^mtcE,B. F.) is a solution of nentral sulphate and citrate of quinia in oran^ wine, made by dis- solving the disulphate (one grain in the ounce) m orange-wine by the help of citric acid. The on^" official preparation of tlie pure disul- phate is Piluia, Qumice, containing three parte salt to one of con- fection of hips (gum arable and honey, U. 8. P.). The remaining Pharmacopceial preparation of quinia is the mixed citrates of iron, ammonium, and quinia {Fernet Qumtx Citras, B. P. and U. S. P.), the well-known scaly compound. It is made by dissolving ferric hy- drate, prepared from ferric sulphate, and quiuia, prepared il'om tlie sulphate, in solution of citric acid, ammonia also being added: the liquid, evaporated to a syrupy consistence and dried in thin layers ong!aasj)latra, yields the usual ^enish-yellow scales (vide p. 115).
^Mimte Valeriana, U. 8. P., is made by dissolving precipitated quinia in warm aqueous solution of valerianic acid and setting aside to cry st alii Ke.
id .y Google
Eeactions.
Fir&t Analytical BeacHon, — To a solution of quiiiia or its salts in faintly acid water add fresli ciilorine-wattir and tben solution of ammonia ; a green coloration is produced.
Second Analytical Reaction. — Kepeat the foregoing re- action,but precede the addition of ammonia by solution of ferrocyanide of potassium ; an evanescent red coloration is produced (Livonius and Togel).
Third Analytical Reaction. — Quinia may be impure from the presence of the other alkaloida (chiefly quiuidia and cinclionia) of einehona-bark ; the following teste will determine the point. The first is Stoddart's modification of Liehig's process.
Into a glass tube or bottle put ten grains of the suspected salt, dissolve in 10 minims of dilute sulphuric acid and 60 minims of distilled water; to this add 150 minims of j?wre ether, 3 minims of spirit of wine, and 40 minims of a solu- tion of soda (1 part of solid hydrate to 12 of water). Agitate well and set aside for twelve hoars, when, if the slightest trace of quinidia or cinehonia be present, they will be seen at the line of separation between the ether and solution of sulphate of sodium.
If only a small percentage of qninidia be present, it will appear as an oiiy substratum, appearing under a lens as dust, from the minuteness of its particles. Cinehonia will appear more decidedly crystalline. With a little practice the eye will easily distinguish which of the alkaloids is de-
Fourth Analytical Reaction. — This is Stoddart's chemico- microscopic test. Into an ounce of distilled water drop 10 drops of dilute sulphuric acid (British Pharmacopceia strength). To this add 14 grains (or as much as wilt satu- rate the acid) of the suspected salt. Filter through paper, and to a little of the filtered solution add a few drops of solution of sulpbocyanide of potassium (180 grains in 1^ ounce of water). An immediate precipitate of the several alkaloids takes place, each of which is distinct and char- acteristic. If quinia, quinidia, and cinehonia be present they will all be seen on the slide, becoming more and more distinct during the first hour. A good plan is to place on a glass slip a drop of the solution to be tested, and to put another of the sulpbocyanide by its side — the drops not being larger than good-sized pin-heads. Over both place a piece of thin glass, which will cause the drops to touch-
id .yCoOglc
822 THE ALKALOIDS.
Examine the line of junction under a half-incli object-glass, when the crystals are readily seen and recognized. By this method tjfcus of a grain of quinidia or cinchonia may be easily detected. The particles arrange themselves into the respective groups — the long slender needles of the quinia salt, the round crystalline masses of the quinidia, and the large well-formed prisms of the cinchonia salts. This re- action is sufficiently constant to enable an observer who has accustomed himself to the general appearance to at once distinguish the respective salts from each other.
The sulphocyanide-of-potassium solution should be of the strength indicated. If not at handitmay quickly be made, sufficiently pure for this reaction, by the following process : Cyanide of potassium (fused), sublimed sulphur, of each ] 20 grains ; distilled water an ounce and a half. Boil in a glass flasfc for fifteen minutes, filter, and make up the quantity to 1^ ounce with sufficient distilled water.
A small quantity of quinia in much cinchonia or quinidia cannot be recognized by the above reaction. Therefore, before concluding that no quinia is present in a specimen of those alkaloids, the sample should be treated with ether, filtered, the solution evaporated to dryness, and the residue, if any, examined for quinia.
Other Gharacters. — Concentrated sulphuric acid dis- solves quinia with production of only a faint yellow color; salicin, with which qninia may possibly be adulterated, slowly gives, under the same circumstances, a deep red.
Concentrated nitric acid dissolves quinia, yielding a co- lorless solution ; on heating, the solution becomes yel- lowish.
Quinia and its salts, heated on platinum foil, burn en- tirely away.
Salicin in quinia may be detected by several other tests {vide p. 345).
OiNCHONiA or CiHCHONiNE (0»|H„N,0) and qninia are distin- guiahed from morphia by non-soIubility of the alkaloid precipitated by a fixed alkali in excess of the alkaline solution. Tney are dis- tinguished from each otlier by the solubility of tlie precipitated quinia and insolubility of ciiichouia when ether is added to the alka- line mixture. Cinchonia, moreover, doM not give the green colora- tion witli chlorine-water and ammonia. Strychnia is also pi-ecipi- tated by fixed alkalies and insoluble in excess, but this alkaloid bas Buck strongly marked reaction of its own as to preclude confusion.
Sulphate of Cinchonia ( Cinohonim S'ldphae, U. S. P.) occurs in. the mother-liquors of sulphate of quinia, and is directly prepared &om several kmds of bark. It forma white, shining crya^ls, having
id .y Google
STRYCHNIA. 325
the form of sliort, obliqne prisms, with dihedral summiis. When heated, it fuses to a resinoia mass of a rioli red color. It dissolves in fifty-four parts of cold water, in much less boiling' water, in seven parts of alcohol, and very sparingly in ether. Its aqueous solution gives with terchloride of gold a yellow precipitate, and with chloride of calcium a white one. Ammonia, added to its solution iu cbiorine water, causes a white precipitate. If the salt be nibbed with water of ammonia, and then treated with ether, the cinchonia, separated by the former, will not be disaolved by the latter.
Qmnidia or Qainidine is an isomer of quinia, and Cinchonidia- or Umchonidine an isomer of cinchonia. Cinehovatia or Ginchch vatine occurs in a particular variety of ciochona-bark. Qidnir.ta or Qtdnicine and Chnchonicia or (hnchonicitie are the products of tbe action of heat ou quinia and cinchonia.
STRTCHHIA, OE STRYCHNINE.
Formula C^H^N^Oj. Molecular weight 334
SoMj'ce.— This alkaloid exists in Nux Vomica (Strychnos Niix Vomica, 'B.Y. and U. S. P.) and ia St. Ignatius's bean tStrychnos Ignatia) {Tgnatia, U. S. P.) chiefly in combination with laetio acid.
Process. — According to the British ofBcial process for its prepara- tion (Strychnvia, B. P.j the nuts, disintegrated by subjection to steam and, after drying, minding in a coffee-miU, are eshausted with spirit, the latter removed by distillation, the extract dissolved in water, coloring and acid matters precipitated by acetate of lead, the filtered liqnid evaporated to a small bulk, the strychnia precipitated by am- monia, the precipitate washed, dried, and exhausted with spirit, tho spirit recovered by distillation, and the residua! liquid set aside to crystallize. Crystals of stiychnia having formed, the mother-liquor (which contains the brnoia of the seeds) is poured away, and the ci'yetals of strychnia washed with spirit [to remove any brucia) and recrystallized.
In the tr. S. P. process the rasped Nux Vomica is exhausted by very dilute hydrochloric acid, milk of lime added to the evaporated decoction to decompose the hydrochlorate of strychnia, the precipi- tated and dried mixture of strychnia and lime treated with diluted alcohoi to remove brucia, and then with strong hot alcohol to dia- solve out strychnia: the alcohol havingbeen recovered by distillation, tho residual impure strychnia is dissolved in very dilute anlphnric acid, the solution decolorized by animal charcoal, evaporated, and set aside to omtallize, the crystals of sulphate of strychnia [Strychnim Svlplias, U. S. F.J redisBolved in water, ammonia added to precipi- tate pure strychnia, and the latt«r dried.
Properties. — Strychnia occurs "in right square octahedrons or prisms, colorless and inodorous ; sparingly soluble in water, but com- municating to it its intensely bitter taste ; soluble in boiling rectified spirit, and in chloroform, but not in absolute alcohol or in ether."
id .y Google
Reactions.
First Analytical Beaciion. — Place a minute particle of strychnia ou a white plate, and near to it a small fragment of red chromate of potassium ; to each add one drop of concentrated snlphuric acid : after waiting a minute or so for the chromate to fairly tinge the acid, draw the latter, by a glass rod, over the strj'clinia spot; a beautiful purple color is produced, qaickly fading into a yellowish -red. The following oxidizing agents may be used in the place of the chromate: puce-colored oxide of lead, fragments of black oxide of manganese, ferridcyanide of potassium, or permanganate of potassium.
Tliis reaction is highly characteristic; a minute fragment dissolved iu inuch dilute alcohol, or, better, chloroform, and one drop of the liquid evaporated to drynesa on a porcelain crncible-lid or other white surfttce, yields a residue which immediately gives the purple color ou being oxidized in the manner directed.
Other JSeaciiOTis,— Strong sulphuric acid does not act on strychnia, even at the temperatiu^ of boiling water, a fact of which advantage is taken ui separating strychnia from other organic matter for pur-
Soses of toxicological analysis. Sulphoejanide of potassium pro- aces, even in dilute solutions of strychnia, a white precipitate, which, uoder the microscope, is seen to consist of tufts of acicular
crystals. Strong nitric acid does not color strychnia in the cold,
and on heating only turns it yellow.
The Physiological 'Test. — A small frog placed in an ounce of water to which fjfj, of a grain of a salt (acetate) of strychnia is added, is, in two or three houra, seized with tetanic spasms on the slightest touch, and dies shortly afterwards.
Strychnia has an intensely hitter taste. Cold water dissolves only fj'^n part; yet this solntion, even when largely diluted, is dis- tinctly bitter. Alcohol is a somewhat better solvent. The salts of the alkaloid are more soluble. The official solution [Liquor Strt/ch- nim, B. F.) contains four grains of strychnia to the ounce, the sol- vent being three parts water, one part spirit, and a few minima (6 per ounce) of hydrochloric acid (rather more than sufficient to form hydrochlorate of strychnia).
Bbuoia, or Bkucikb (053Hj,N304,4H30), is an alkaloid accompany- ing strychnia in Nux Vomica. It is readily distinguished by the
tense red color produced when nitric acid is added to it. Igasuria,
another alkaloid of Nux Vomica. This alkaloid is said to occur
no leas than nine varieties, each slightly differing from the other chemical composition. They resemble strychnia in ph^ical properties.
Distinction of Bructafrom Morphia. — The red coloration pro- duced by the action of nitric acid on brucia is distinguished from that yielded by morphia by the action of reducing agents (such as
id .y Google
staiino>i3 chloride, hyposulphite of sodium, snlphydrate of sodium), wliich decolorize the morphia-red, but change that of the brucia to violet and green (Cotton).
QUESTIONS AND EXBEOISBS.
GGO. Wliat alkaloids are more or less characteristic of tlie differeat varieties of cinchona-bark? In what form do they occur?
661. By what method is Disniphate of Quinia obtained ?
662, Give the characters of disulphate of quiaia. 6S3. Describe the tests for quinia.
664. How is the adulteration of disulphate of quinia by salicin detected ?
665. Show how the sulphates of quinidia or ciuchonia may be proved to be present ia commercial quinia.
'666. How are cinchonia and quinia distinguished from morphia? 661. Whence ia Stmhnia obtained?
668. Describe the official pcoeess for the isolation of strychnia.
669. Give the characters of strychnia.
670. Enumerate the tests for strychnia, and describe their mode of application.
671. By what I'eagent is brucia distinguished from strychnia?
672. Distinguish between brucia and morphia.
ALKALOIDS OF LESS FEEaUEHT OCCUREENCE.
AooNiTiA, AcoNiTiNA, Or AcoNiTiNE (OjaH.jNO,) is an alkaloid obtained from aconite (Aconttum Napellusyiea,vea (Aconiti Folia B. P. and U. S. P.) and root {AconiU Radix, B. P. and XJ. 8. P.). The alkaloid itself is only slightly soluble in water; it occTirs ia the plant in combination with a vegetable acid, forming a solnble salt.
Process. — The official process for its preparation {Aconitia, B. P. and U. 8. P.) consists in dissolving out the natural salt of the alka- loid from the root by rectified spirit, recovering the latter by distilla- tion, mixing the residue with water, filtering, precipitating the aconitia by ammonia, drying the precipitate and digesting it in ether (in which some of the accompanying impurities are insoluble), recovering the ether by distiUation, dissolving the dry residue in the retort in water acidulated by sulphuric acid, again precipitating the alkaloid by ammonia, and finally washing and drying.
Properties. — Aconitia usually occurs as a white powder, soluble in 150 parts of cold water, 50 of hot, and much more soluble in alcohol and in ether. The chemical reactions of aconitia are not sufficiently well marked to admit of application as qualitative teats. It is one of the most violent poisons known. " When rubbed on the skin it causes a tingling sensation, followed by prolonged numbness."
JTnguentum Aconittce, B. P., contains eight grains of the alkaloid to one ounce of prepared lard.
id .y Google
32G THE ALKALOIDS.
Atbopia, or Atropine (C„H„N0,), exiats in the Belladonna, or Deadly Nig-htahade (Atro^a Belladonna: Belladonna Folia et Hadix, B. P. and V. S. P.), as soluble acid malate of atropia.
Process. — It is obtained in the pure state by exhausting the root with spirit, precipitating the acid and some coloring-matter by lime, filtering, adding sulphuric aeid to form sulphate of atropia (which is somewhat less liable to decomposition dnnag subsequent operations than the alkaloid itself), recovering most of the spirit by distillation,
adding water to the residue, and evaporating till t — _
spirit la removed ; solution of carbonate of potassium is then poured in till the liquid is nearly but not quite neutral, by which resinous matter is precipitated ; the latter is filtered away, excess of carbonate of potassium then added, and the liberated atropia dissolved out by shaking the liqnid with chloroform. The latter solution, having subsided, is removed, the chloroform recovered by distillation, the residual atropia dissolved in warm spirit, coloring matter separated by digesting the liquid with animal charcoal, the solution filtered, evaporated, and set aside to deposit crystals.
Solubility. — Atropia is sparingly soluble in water, the liquid giving an alkaline reaction- — more soluble in alcohol and ether.
Tests. — Atropia-solutions give with perchloride of gold a yellow precipitate. One drop of a dilute aqueous solution (two grains to the ounce) powerfully dilates the pupil of the eye. It is applied on a piece of thin tissue paper or small disk placed between the eyelid and the eye.
Preparations. — The alkaloid itself [Atropia), its sulphate {Atro- pia Sulphas, a colorless powder soluble in water, made by neutral- izing atropia with sulphuric acid), their solutions {Liquor Atropim, four grains per ounce, and Idquor Atropim Sulphatis, four grains per ounce), and an ointment ( Unguentnm Atroptis, eight grains per ounce) are the preparations official in the British Pharmacopeia. The alkaloid and its sulphate are official in the United States Phar- macopceia.
Daluria or Datwrine, an alkaloid in Datura Stramoniv/m or Thorn-apple (Stramomi Folia et Semina, B. P. and U. S. P.), ap- pears to be identical with atropia.
Bebebia, or BsBBBiHE (C„lLiNO,), is an alkaloid existing in the bark of Bebeeru {Nectandra Jtodzie*).
Process. — According to the British Pharmacopceia, it, or rather its sulphate, C„H„N/)a, HjSO, (BeSerire Sulphas, B. PJ, may be prepared by exhausting the bark (Nectandra Cortex, B. P. and tl. 8. P.) with water acidulated by sulphnric acid, concentrating, removing most of the acid by lime, filtering, precipitating the alka- loid by ammonia, filtering, drying, dissolving in spirit {in which some accompanying matters are insoluble), recovering most of the spirit by distillation, neutralizing by dilute sulphuric acid, evaporat- ing to dryness, dissolring the residual sulphate in water, evaporating to the consistence of a syrup, and spreading on ^lass plates, drying the product at ]4(P. Thus obtained, it occurs in thin dark-bromi translucent scales, yellow when powdered, strongly bitter, soluble in water and in alcohol.
id .y Google
BEUBERIA, 327
yesis.— Alkalies give a pale jellow precipitate of beberia when added to an aqueous solution of a salt of the alkaioid ; the precipi- tate is soluble in ether, With red chromate of potaasium and sul- phuric acid beberia gives a black reain, and with nitric acid a yellow
Nectandria {CjoHjjNOj). — Drs. MaclaMn and Gamgee have re- cently discovered this second alkaloid in Bebeeru bark. It differs fromceberia in ftising when placed in boiling water, in being much less soluble in ether, in giving with strong sulphuric acid ana black oxide of manganese a beautiful green and then violet coloration, and in having a, distinct molecular weight. They are of opinion that two other alkaloids exist in Bebeeru bark.
Bbbbkeia, or Bbbbebinb (0^H,,N0J, is an alkaloid existing in several plants of the natural order Bcrheridem, in Calnmba-root (GalvmhiE Radix, B. P. and U.S. P.), Goldthread ( Coptic trifoiia, U. S. P.) according to Mayer, and in many yellow woods. The color of the tissues of these vegetables is apparently due te berberia; for the alkaloid itself is remarkabie for ite beautimi yellow color.
Testa. — When a dilute solution of iodine in iodide of potassium is added to solution of any salt of berberia in hot spirit, excess of iodine being carefally avoided, brilliant green spangles are depMited. The reaction is snfBciently delicate to form, according to Perrins, an excellent test of the presence of berberia. This iodo-compound polarizes light, and has other analogies with a similar quinine-salt termed herapathite.
Berberia is not an official alkaloid; but the plants in which it occurs are used as medicinal agents in all parts of the world.
Process. — Berberia is readily extracted by boiling the raw material with water, evaporating the strained liquid to a soft extract, digest- ing the residue in alcohol, recovering the alcohol by distillation, boiling the residue with diluted sulphuric acid, filtering and setting aside; the sulphate of berberia separates out, and may be purified by recrystallization from hot water. The alkaloid itself is obtained by shaking hydrate of lead with a hot aqueous solution of the sul- phate of berberia (Proctor).
Podophylhm--root (FodophylH Radii:, B. P., PodophyUum, F. S. P.), contains berberia. In preparing the resin of podophyllum or May-apple (Podophylli Bestna, B. P. and U. S. P.) an alcoholic extract of the root is poured into water acidulated by hydrochloric acid, whereby the whole of the hydrochlorate of berberia, which is almost insoluble in dilute mineral acids, is precipitated with the resin (Maiseh). No acid is ordered in U. S. P.
Capsicia, or Oapsicinb, is an alkaloid occurring in Cayenne pep- per or Capsicum-fruit (Capsici fVucttis, B, P. and U. S. P.), asso- ciated with resin and volatile oil. It is crystalline, and forms crys- tallizable salts with acids.
Cissampblia, Cissampelinb, Pblosia, or Pklosine (C[jHj|NOs), is an alkaloid occumng in the root (PareiTce Radix, B. P. and U. S. P.) of Cissampelos Pareira. It is the tonic and diuretic principle of the drug,
id .y Google
338 TUE ALKALOIDS.
Con I A, OoNYLiA, Conihe, Cokicikb, or Cicpiibb.— Fomiula CjH.jN, or (CsH,.)"HN. This alkaloid is a volatile liquid, occur- riug m hemlock (Oonrnm mactdalum). It ia not official.
Process. — It wavbe obtained by distilling hemlock-fruit {Comi Fmctus, B. P.) with water rendered slightly alkaline by canstic soda or potasL, or by Bimilarly treating the fresh juice of tie leaves. The alkaloid is a yellow oily liquid, floating on the water that distils over 1 by redistillation it is obteioed colorlera and transparent.
The salts of coma have no odor, but when moistened with solu- tion of an alkali yield the alkaloid, the strong smell of which, at once recalling hemlock, is characteristic. Exlroet of hemlock leaves (ComiFoUa, B. P. and TJ. S. P.), to which solution of potash and boiling water have been added, fonna the official Inhalation of Oonia (V^or Coniee, B. P.).
Tests. — Sulphuric acid tnms conia purplish-red, changing to olive- green, nitric acid a blood-red ; perchloride of gold produces a yel- lowish-white precipitate, perchloride of platinum no precipitate, in aq aeons solutions.
Hemlock also contains metliyl-conia {C^u)" CHjN (Kekul^ and Van Planta).
EstBTiA or BMBTiirB (Cj^j.NsOg). — This alkaloid is the active emetic principle of O^hcehs tpecaoaaiilia (Iipecaeitanka,, B. V. and TJ. S. P.). It occurs in combination with ipecacnanhic acid. The nitrate is peculiarly slightly solnble in water (Lefort). In the Pul- vis Ipecacuanha;, B. P. and U. S. P., or "Dover's Powder" (Pow- dered Ipecacuanha, 1 part; Powdered Opinm,! part; and Sulphate of Potassium, 8 parts), minute division of the active ingredients is promoted by prolonged tiitniatiOQ with sulphate of potassium, which IS a very hard salt.
Hyoscyamia, or HTosCYAJirNu, a volatile alkaloid, is said to occur in the leaves J jffyoscynmj J'oto, B. P. and TJ. S. P., Hyoscyami Semen, 17. 8. P.), and other parts of Henbane.
Lobelia, or Ix)bblihb. — A volatile alkaloid first isolated from the dried flowering herb Lohelia inflata (Lohelia, B. P. and U. S. P.) by Bastick.
Nectanbkia, vide Beberia.
NiooTiA, NiconsA, Nicotylia, or Nicotine.— Formnla C,„HijN;, or (C5H,)"'jN,. This is also a volatile liquid alkaloid, forming the active principle of tobacco (Nicotiana tabacimi), malate and ci- trate of nicotina being the forms in which it occurs in the leaf { Tdbaci Folia, B. B. and U. S. P.). Its odor is characteristic ; like conia, it yields a precipitate with perchloride of gold ; but, unlike that alkaloid, its aqneoas solutions are ^-ecipitated yellowish-white by perchloride of platinnm. It ia not offlcial,
PHYaosTioMiA, or PHYSosTiauiNB. — An alkaloid contained in the Calabar Bean (Pkysostigmatis Faba), the seed of Pliysostigina venenosunt (Jobst and Hesse). A trace of it powerfully contracts the pupil of the eye ; a small quantity is highly poisonous. Praser also isolated this principle, and termed it Eserta, item E^rS, the name of this ordeal-poison at Calabar.
id .y Google
PIPERINE — VERATKIX'E. 329
PiPHKiA, or PiPEHiNE (CiiHijNOa), is a feeble alkaloid oooniring in white, black (Piper Niqrwm, B. P. and IJ. S. P.), lona, and e«- heb pepper [Ciibeba, B. P. and U. 8. P.), associated with volatile oil aud resin ; to these three substances the odor, flavor, and acridity belong. Piperia is obtained on boiling white pepper with alcohol, and evaporating the liquid with solution of potash, which retains re- sin. Becrj^tallized from alcohol, piperia forms colorless prisms fusi- ble at 212^^. With acids it forms salts, and distilled with strong alkali yields jwpmdja or piperidtne, an alkaloid of strong chemical properties.
Sangmnarina, or Sangmnwrine (CnjHj^NjOj) is a colorless alka- loid obtained. from the rhizome of Sanguvnana Canadensis (U. 8. P.) or Blood-root. Its salts have a red, crimson, or scarlet color.
SoLANiA, or SoLANiNE (QuH,(,NO,j).- — All alkaloid said to existia the Woody Nightshade or Bitter-sweet {Sdanuih dvieamara). The dried young branches of the plant are official {Dvlcavuira, B. B. and U. 8. P.).
Spaktsia, or Spaeteihb (C,jH^N), is a poisonous volatile alka- loid occurring in Broom-tops (Scoparii Caeumina, B. P. and U.S. P.). Its discoverer, Stenhonse, considers that the diuretic principle of broom is Scopm-in, a, non-«oisoaoua body.
Thbu, Theine, or Caffeine {C^Jn«0,+H^O.)— This alkaloid occurs in tea, coffee {Gaffea, U. 8. Y.), Paraguay tea, guarana, and the kola-nut. Infusions and preparations of these vegetable pro- ducts are used chiefly as beverages by three-fourths of the human race. It is remarkable that the instinct of man, even in bis savage state, flhonld have led him to select, as the bases of common bever- ages, just the four or five plants which out of many thousands are the only ones, so far as we know, containing theia.
Itesi,— Concentrated nitric acid, or a mixture of chlorate of potas- sium and hydrochloric acid, rapidly oxidizes theia, forming com- pounds which with ammonia yield a beautiful purple-red color, re- sembling the mnrejdd obtained under similar circumstances from uric acid; the oxidation must not be carried too far. Theine boiled with caustic potash yields methylamine (OHjHHN), the vapor of which has a peculiar, characteristic odor.
The chendcal action of theia on the system is not yet made out, Liebig thinks it may aid in the production of a suhatanoe a normal amount of which is so necessary, an abnormal so unpleasant — namely, bile. Most chemists agree that it arrests the rapid consumption of tissue and consequent feeling of fatigue which is especially experi- enced after hard work with mind or body,
Ybkaieia, or Yebatbihb (OjjHsjNjOa).— This alkaloid occurs as gallate of veratria in various species of Veratrum (Hellebore) (as Vei-atram Album, U.S. P., Veratri Viridis Kadix, B. P, anA U. S. P.), in Cevaditia {Sabadilla, B. P. and U, S. P.), and i)i the cor- mus or so-called root of Colchieum avtimnalelColchiei Corvtus ; Colchici Semina, B. P. and U. 8, P.). White Hellebore is a!eo said to contain three other alkaloids, sabadilHa or sabadilline, colehicia or colchieine, and jervia or jervim- A mere trace of yerafria brought into contact with the mucous membrano of the ni»e causes
id .y Google
330 THE AL HALOIDS.
violent fits of sueeziDg. Fuming sulphuric acid colors it yellow, red. and violet in snccessioo.
The official process for the preparation of the alkaloid ( Veratria, B. F.) coBsista in exhausting- (he disintegrated cevadilla seeds by alcohol, recovering most of the spirit by distillation, pouring the residue into water, by which mnch resin is precipitated, filtering, and precipitating the veratria from the aqueous solution by ammonia. It IS purified bj washing with wat«r, solution in dilute hydrochloric acid, decolonzation of the. liquid by animal charcoal, reprecipitation by ammonia, washing and drying. The U. 8. F. proce^ is similar, but includes treatment of the first crude veratria by dilated sulphu- ric acid and precipitation of alkaloid by magnesia.
IJnguentuw, Verntrix, B. P., contains eight grains of the slightly impure alkaloid obtained as just described, rubbed down with halt a drachm of olive oil and diffused through one ounce of prepared lard.
QUESTIONS AND EXERCISES.
673. Howis Aconitia prepared?
674. Give the strengths of the offic'al prej a at'ons of Atropia.
675. Describe the properties of atr p a
676. What is the active principle of stramon um
677. Mention pharraacopteial snlstan es o ta g bebcria and berberia respectively.
678. Give the characters of beber a
679. In what does neetandria dififer f on be! ena ?
680. Mention the characteristics of con a
681. What is the active principle of Ipecacuanha?
682. Name the alkaloid of Tobacco.
683. Give the name and properties of the active principle of Cala- bar Bean.
684. What are the sources of piperia 1
685. Whence is theia obtained ?
686. Describe the preparations of Veratria.
687. State the properties of veratria.
BITTER (TONIC) SUBSTANCES.
The following ofBcial articles, commonly employed medicinally in sueh forms as Decoction, Extract, Infusion, Tmcture, contain active principles which have not yet been thoroughly examined. Some of these principles have been isolated, and a few have been obtained in the crystalline condition ; bnt their constitution has not been sufficiently well made out to admit of the classification of the bodies either among alkaloids, glucosides, apids, or other well-inarkeij principles,
id .y Google
Absinihium (Abamtliin). Gentiana; rad-ix.
AiUhemidts Jflores. Lactuca (Lactucin).
Awrantii cortex. Lupulus.
Buchu folia. Maticce folia.
Oanellce allts cortex. Ma/rTuhium.
Cascarill(e corteo). Quassice lignwn, (Qi
Chirata. H,jO0.
Chimaphila. Serpentarice radix.
Cu^arim cortex, or Angustura, Spigdia marilandiea.
TLS. P., contains Cnsparin or Taraxaci radix i^i" Angustarin.
AMYLACEOUS AND SACOHARINE SUBSTANCES.
Formula CaH,„0,. Processes. — Rasp or grate, or, with a knife, scrape a por- tion of a clean rawpotato, 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 par- ticles or granules of starch pass through the muslin and sink to the bottom of the vessel, fibrous matter remaining on the sieve. This is potato-starch. Wheat-starch (Ami/- lum, B. P. and TJ. 8. P.) 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 washings running into a deep vessel, at the bottom of which the white 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 curious columnar masses, resembling the basaltic pillars of Fingal's Cave in StaflTa, or those of the Giant's Causeway in the Nocth of Ireland. The cause of the phenomenon, which may also be seen in grain-tin, is not conclusively known.
fflulen is the body which gives tenacity to dougli and hreod. It seems to be a mixture of vegetable fibrin, vegetable caseiu, and an albuminoua matter termed glntin. These sahstancea and gluten itself are closely allied; each containB about 16 per cent, of nitrogen. Wheaten Flour {Farina Tritici, B. P.) contains about 72 per cent, of starch and 11 of glotfin, as well as sugar, gum, fine bran, water, and ash. The commctness of barley, well seen in Husked or Pearl Barley (Hordewm Decorticatxim B. P. and U. S. P.), is said to he due to the large amount of vegetable fibrin present During ger-
id.y Google
31}2 AMYLACEOUS AND SACCHARINE BUBBTANOES.
mination the fibrin is destroyed, hence, probably, the cretaceons character of malt. Oatmeal {Avenw Fartna, U. S. P.) is very rich in albuminoid or fl.esh-forraing constitnents, containing nearly 16 per cent. Sago, tj. S. P., is granulated starch from the Sago Palm. Tapioca, U. S. P., is granulated starch from the Bitter CaBsava.
Mucilage of Starch. — Mix two or three grains of starch Tvith first a little and then move water, and heat to tbe boiling-point, mucilage of starch {MucUago Amyli, B. P.) results.
This mucilage or paste is not a true solution ; by long boiling, however, a portion of the stareh becomes dissolved. In the latter case the starch probably becomes somewhat altered.
Chemical Teat. — To some of the mucilage add a little free iodine ; a deep-blue color is produced.
"niis reaction is a very delicate test of 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 be first boiled in water. The solutions used in the reactions should also be cold, or nearly so, as the blue color disappears on beating, though it is partially restored on cooling. The iodine reagent may be iodine-water or tmcture of iodine. In testing for iodine its occur- rence in the free state must be insured by the addition of a drop, or even less, of chlorine-water. Excess of chlorine must be avoided, or chloride of iodine mill be formed, which does not color starch.
The so-called iodide of starch scarcely merits the name of a chemical compound, the state of union of its constituents being feeble. Substances that attack free iodine remove that element from iodide of starch. The alkalies, hjdrosulphuric acid, sulphurous acid, and other reducing agents destroy the blue color.
Microscopical test. — All kinds of starch yield the blue color with iodine, showing their chemical similarity. But physically the granules of starch from different sources differ much in size and appearance when examined by the microscope with or without the aid of polarized light. The grwinlea of potato-starch are large, of rice-atarch very small, arrowroot {Maranta, U. 8. P.), and wheat- starch being intermedial*. By polarized light the granules of potato- starch appear as if traversed by a black cross, the wheatstarch grannies, as seen in common flour, yielding no such elTect. (See the frontispiece plates of the original edition of Pereira's "Materia Medico.") The granules of Tons les Mois (Oanna, U. S. P.) are very large.
Dextrin. — Mix a grain or two of starch with about balf a test-tubefnl of cold water and a drop or two of sulphuric acid, and boil the mixture for a few minutes ; no mucilage is formed, and tbe liquid, if suflSciently boiled, yields no blue color with iodine; the starch has become converted into dextrin. The same elfect is produced if the starch is
id .y Google
DEXTRIN, 333
maintained at a temperature of about 320° P. for a short time. Dextrin is now largely manufactured in this way, and a paste of ifc used by calico-printers as a vehicle for colors ; it is termed British gum. The change may also be effected by diastase, 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 or pudding, that with malt remains thin, its starch having become converted into dextrin.
Diastase is probably the vegetable fibrin of gluten in & state of decompoaition ; it is so named from Bmaraats {diastasis), separation, in allusion to the separation, or rather alteration, it effects among the constitnent atoms of starch.
Malt (the word malt is said to be derived from the "Welsh maU, soft) is simply barley which has been softened by steeping in water, allowed to germinate slightly, and further obauge then arrested by the application of heat in a kiln. During germination the gluten breaks up and yields a glutinous substance termed vegetable gela- tine, diastase, and other matters. To the vegetable gelatine is dae much of the " bod/' of well-maltfld and slightly-hopped beer ; it is precipitated by tannic acid, hence the thinness of ale (pale or bitter) brewed with a large proportion of hop or other materials containing tannic acid. A portion of the diastase reacting on th ta h f tl barley converts it into dextrin, and, indeed, carries t th
further stage of grape^ugar, as will be explained imm d at ly Th temperature to which the maJt is heated is made to y th t the sugar of the malt may or may not be partially Ite d t d k brown coloring material ; if great, the malt is said t b } jl I d and is used in porter-brewmg ; if low, the prod t f 1 j,ht color, and is used for ale. The diastase remaming n nalt 1 11 capable of converting a large quantity of starch t d xt n d sugar ; hence the makers or distillers of the vario p t p te on a mixture of malted and unmalted grain in prep g 1 q rs f fermentation.
Gwm, is a frequent constituent of vegetable juices, existing in large quantity in several species of acacia. According to Fremy gum is a caloium salt, sometimes partially a potassium salt of the
Swnmic or arahic radical. The formula of gammic acid is said to e HjC,jH,gOio, H,0. Gnm differs from dextrin in yielding oxalic acid but no mucic acid when oxidized by nitric acid. Cerasin or cherrff4reegum is an insoluble raodificatioQ of acacia gum. Bas- sorin (Oi.B^Oio) is a form of gum which is insoluble in water, but absorbs a large quantity of that liquid and forms a gelatinoid mass. It occurs largely in 1'ragacauth, combined, like arabin, with calcium. Pectin or vegetable jelly {G,^^0^,^Rfi) is the body which gives to expressed vegetable juices the property of gelatinizing. It forms the chief portion of Irish or Carrageen moss ( Chonch'Us crispua, V. S. P.).
id .y Google
Isomerism. AUotropy. Polymorphism.
The composition of dextrin is represented by the same formula as that of atarch, namely OsHijOj; for it has the same percentage composition as starch. There are many other bodies similar in cen- tesimal composition, bnt dissimilar in properties ; such aabstances are termed ^B01neT^c (from iOo(, isos, equal, and ("'po(, meros, part) ; and their condition is spoken of bb one of isomerism. There is some- times good reason for doubling or otlievwise multiplying the formula of one of two isomeric bodies. Thus oleflant gas (ethylene), the chief illuminating; constituent of coal-gas, is represented by the formula OjH,, while amylene, an ansesthetic liquid hydrocarbon, obtained from amylic alcohol, though having the same percentage composition as olefiant gas, is represented by the formula C^1i,„ ; for the latter, when gaseous, is about twice and a half as heavy as the former, and must contam, therefore, in equal volumes, twice and a half as many atoms ; its formula is, consequently, for this and other reasons, constructed to represent those proportions. This variety of isomerism is termed polymerism (from noiiuf, potHs, many or much, ■and fUpof, part). Metastannic acid (vide p. 197) is a polymeric variety of stannic aeid. Au illustration of a second variety of iso- merism is seen in the case of cyanate of ammonium and urea, bodies already alluded to in connection with cyanic acid. These and several other pairs of chemical substances have dissimilar properties, yet ate similar not only in elementary composition and in the centes- imal proportion of the elements, but also in the fact that each mole- cule possesses the same number of atoms. But the reactions of these bodies indicate the probable nature of their construction ; and this is shown in their formula by the disposition of the symbols. Thus cyanate of ammonium is represented by the formula NHjCNO, urea by OH.NjO. Such bodies are termed metamerie (from futa, meia, a preposition denoting change, and ttifoi), and their condition spoken of as one of ntetameristn. The isomerism of starch and dextrin may be of a polymeric or of a raetameric character ; but we do not yet know which, and must therefore at present give them identical formula. Substances similar in composition and constitution, yet differing in properties, are termed allotropic (qMji(, ailos, another, I'pdrfof, tropos, condition). Thus ordinary phosphorus, kept at a temperature of about 45CP Fahr., in an atmosphere from which air is excluded, becomes red, opaque, insoluble in liquids in which ordi- nary phosphorus is soluble, osidizes extremely slowly, and only ignites when heated to near 500° Fahr. (red or amorphous phospho- rus). Another illustration of allotropy is seen in certain varieties of tartaric acid, which have different optical properties, but other- wise are identical ; they are in. neither of the above-mentioned states of isomerism, but are allotropic modifications of the same substance. Occasionally one and the same substance crj^talliaes in two distinct forms, its state is then described as one of polymorphism (jtoxvf, potHs, many, popprj, nwrphe, form). Sulphur is polymorphous. It crystallizes by slow cooling in (1) prismatic crystals of sp. gr. i.98, while in nature it occurs in (2) octahcdra of sp, gv, 2.07. Mellcd
id .y Google
NITilOCELLULIN, 335
and poured into water, sulphur takes up the form of (3) caoutchono of sp, gr, 1.96. These differences warraot the statement that sulphur occurs in three distinct allotropic conditions.
Cdlulin or cdlvloee, the woody fibre of plants, familiar, in the nearly jiure state, nnder the forms of "cotton-wool" (GosswpzMm, B, P, and U. S. P., " hairs of the seed of various species of Gossy- pium"), paper, linen, and pith js another substance isomeric, probably polymenc, with starch. Lignin is a closely allied body, lining the interior of woody cells and vesseis. By the action of nitric acid of various strengths on cellulin, peroxide of nitrogen (NOJ is substi- tuted for one, two, or three atoms of hydrogen — mono-, di-, or tri- nitrocellulin being formed; —
0«H,„05 + HNO, = Oj I ]^ I Oj + H,0
Cennlin. Nitric aoicU MottonitroceUnllii. Waler.
C^HiA + 2HN0, = 0, { 2^5 J O5 + 2H,0 OJI,oO, -f 3HN0, = C, 1 3f^5 I O, -)- 3H,0
Trinitrocellulin is highly explosive gnn-cotten ; dinitrocellulin is not saEBciently explosive for nse instead of gunpowdor; moaonitrocel- lulin is scarcely at all explosive.
Dinitrocellulin {Pyroxylin, B. P.) may be prepared by the following process: Mix 5 fluidounces of sulphuric acid and 5 of nitric in an earthenware mortar, immerse 1 ounce of cotton-wool in the mixture, and stir it for three minutes with a glass rod, untii it is thoroughly wetted by the acids. Transfer the cotton to a vessel containing water, stir it 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 washing ceases to give a precipitate with chloride of barium. Drain the product on filtering paper, and dry in a water-bath.
Mononitroc^hdin and trimtrocellulin are insoluble in a mixture of alcohol and ether ; tUnitroceUulin or pyroxylin is soluble, the solu- tion forming ordinary collodion {Gollodium, B, P. and U. S. P.). The official proportions are 1 ounce of pyroxylin dissolved in a mixture of 36 fluidounces of ether and 12 of rectified spirit. After digesting for a few days, the liquid is decanted from any insoluble matter and preserved in a well-corked bottle. It is "a colorless highly inflajn- Bable liquid with ethereal odor, which dries rapidly npon exposure to the air, and leaves a thin transparent film, insoluble in water or rectified spirit." Flexible collodion ( Collodium Flexile, B. P.) is a mixtare of collodion (6 fluidounces), Canada Balsam (120 grains), and castor oil (1 fluidrachm).
id .y Google
336 AMYLACEOUS AND SACCHARINE SUBSTANO
QUESTIONS AND EXEECISES.
68B. How is wheat^tarch or potato-starch isolated?
689. Define gluten and glutin.
690. Enumerate the proximate principles of wheaten flour.
691. Is starch soluble in water ?
692. Which is the best chemical test for starch?
693. Distinguish phjsicalij' between the varieties of starch.
694. Into what compound la starch converted by heat!
695. What occurs when a mixture of starch and water is allowed to flow into hot diluted anljphuric acid?
696. If equal amounts or starch and water be heated, one contain- ing a small quantity of ground malt, what effects ensue ?
697. Write a short article on the chemistry of " malting."
698. Explain isomerism, as Ulustrated by starch and dextrin.
699. Give examples of polymeric bodies.
700. State the formula of a body metameric with urea.
701. Define aUolropy and polymorphism, giving illustrations.
702. What form of^eellnlin is ofBctal?
703. Mention the properties of the products of the action of nitric acid of various strengths on cellulzn.
704. How is pyroxylin prepared?
SUGAR.
Foi-mula G,,H,^0„. ArUficial formaiion of Grape-sugar from Cane-sugar. — ■ Tests for Sugar. — Dissolve a grain or two of common 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 sulphate of copper, a considerable quantity of solution of potash or soda (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 change occurs. To another portion of the syrup add a drop of sulphuric acid, and boil for ten or tvi'enty minutes, then add the copper solu- tion and alkali, and heat as before ; a yellowish-red pre- cipitate of cuprous oxide (CUjO) falls. This test is "y delicate.
The above reaction is due to the conversion of the cane-sugar (Cj^H-Oi,) into a kind of ^rape^ugar {G.fi^fi^^, or 208H|jO„) by the influence of the sulphuric acid, and to fie reducing action of the grape sugar on the cuprie solution. The formation of a precipitate immediately, without the action of acid, shows the presence of grape- sugar — its formation only after ebullition with acid indicating, in the
id .y Google
OANE-SUOAR — QRAPE-SUQAR. 33t
absence of starch or dextrin, cane^ugar. In this process the sugar is oxidized and broken up into sevem substances; the exact nature of the reaction has not been ascertained.
Cane-sugar or sucrose (Saccliaram Pwrificaium. B. P. and U. 8. P.) is a frequent constituent of vegetable juices. Thus it forms the chief portion of casaia-pulp ( Oassice Pulpa, B. P.) and Fig (Ftmis, B. P. and U. 8. P.) bnt is most pie ntiful in the sugar-cane; much, however, is now obtained from fie sngar-maple and beetroot. On the evaporation of the jniee, common brown or mm'st sugar crystal- lizes out; tliis by resolution, filtration through animal charcoal, evaporation to a strong syrup, and crystallization in monlds, yields the con(pact crystalline conical loaves known in trade as lump-sugar. From a slightly less strong syxup, slowly cooled, the crystals termed sugar-candi/ are deposited, white or colored according to the color of the syrup. Grape sugar or glucose (from ■fljrxvi, glucus, sweet) is often seen in the erjstalliaed state, in dried grapes or raisins and other fruits ; it is also the variety of sugar met with in diabetic urine. Both varieties twist a ray of polanzed light from left to right, to an extent dependent on the amount of sugar present — a fact easy of application in estimating the amount of sugar in syrups or in diabetic arine.
Both cane-sugar and grape-sugar yield alcohol and carbonic acid gas by fermentation, the cane-sugar probably always passmg ioto grape-sugar before the production of alcohol
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 (dongh) — the temperature to which the mass is subjected in the oven causing escape of alcohol, and farther expansion of the bubbles of carbonic acid gas in every part of the now spongy loaf. The carbonic acid gas gradually evolved when flour 18 worked up for bread with a mixture of dry bicarbonate of sodium and tartaric acid (best preserved by previous admixture with a little dried flonr) — halang-nov)der — exerts similar influence. The least objectionable method of introducing carbonic acid gas, however, is that of Dauglish, whose patent ASrated Bread is made from flonr by mere admixture with carbonic-acid water under pressure. On removal from, the cylinder, the resulting dough expands by the natural elasticity of the imprisoned carbonic acid, and the bake-oven completes the process. The crumb of bread is official (Mica Pams, B. P.).
Miikrsugar or lactose {Saccharam Lactis, B. P. and U. S. P.), the sweet principle of the milk of various animals, is not susceptible of alcoholic or vinous fermentation; but it resembles grape-sugar in reducing an alkaline solution of copper with precipitation of sub- oxide. It is readily obtained from milk by adding a few drops of acid, stirring, setting aside for the curds to separate, Altering, evapo- rating the whci/ to a small bulk, filtering again if necessary, and al- 29
id .y Google
33R AMYLACEOUS ANT) SACCHAEINE SUBSTANCES.
lowing to cool and cvystalliae. It usually oceura in trade " in cylin- drical masses, two inches in diameter, with a cord or sticic in the asis, or in fragments of cftlie8™grajish-white, crystalline on the surface and in its texture, translneent, hard, suentless, faintly sweet, gritty when chewed." It is solnble in 6 parts of cold and 3 of boiling water ; slightly soluble in alcohol ; insoluble in ether.
Action of Alkali on Sugar. — To a little solution of grape- sugar add solution of potash or soda, or solution of car- bonate of potasaium, and warm the mixture; the liquid ia darken 1 1 fmnL tbwna Intth
amount t g p t
Tests— Th ppe t th f m t t p ess d th
effect of Ik 1 f th good t ts f th p se f K pe-
sugar, a d d tly f ga A p f m tl
woollen telp lydjid J ft lid
and dri d b m f b bl b 1 wl d pp d I
tioa of glucose and heated to about 300° F. by holding before a fire.
Sugar from Starch. — Boil the starch with a little water and a drop of sulphuric acid as for dextrin, 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 copper salt as described on page 336, it will be found that the starch has nearly all become converted into grape-sugar, or starch-sugar as it is sometimes termed. When made on a large scale, a warm (131° F) 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 chalk, the mixture filtered, the liquid evaporated to a thick syrup and set aside ; in a few days it crystallizes to a granular mass resembling honey. In this operation a small quantity of dextrin re- mains with the glucose; but if the process be conducted under pressure, conversion, according to Manbre, is com- plete.
37te stLgar in fresh frmte is mainly cane-sngar; but by the action of the acid, or possibly of a ferment in the juice, it is gradually con- verted into inverted sugar, a variety differing from cane-sugar in being uncrystalhzable, and in having an inverted or opposite influ- ence on polarized hght, twisting the ray ft-om right to left (Itevogy- rate, having Itevo-rotation — hence sometimes tenned levulose). Eipe Hips (jBosce Canince Friictus, B. P.) contain 30 per cent, of such sugar. Frnit-sugar, as gathered in the form of syrup by bees, is probably a mixture of ttiese two varietiw. It is gradually altered to a crystalline or granular mass of grape-sugar, as seen in dried
id .y Google
friiitB, Bucli a3 liaisms {Uvce, B. P., Uva Fauna, U. 8. P), and the Pruae {Prununi. B. P. and tl. S. P.), and in Bolidifled honey {Mel, B. P. and tJ. 8. P.). This, the common form of grape-sugar, ie dex- trogyrate, and hence is sometimes termed detetToae, to distinguish it from levulose. Honey often contains floccnlent matters which cause it to ferment and yield manuite ^Stoddart), alcohol, and acetic acid ; hence for ase in medicine it is directed (Md Depwratum, B. P. and TJ. 8. P.) to be clarified by melting and straining, while hot, through flannel previonsly moistened with warm water. A. mixture of clari- fied honej 80 per cent., acetic acid 10 per cent., and water 10 per cent, is official under the name of Oxymd (from dfif, or&a, acid, and imJls, meli, honey). A similar mixture of honey with acetic acid containing the soluble portions of squill-bulbs (Seilla, B. P. and U. S. P.) ia known as Oxymel of 8qnill f O^/meZ SdUce, B, P.), Honey or cane-sugar are the bases of the official Confections.
Barley sugar is made by simply heating onn&«ugar till it fuses, a cbange from the crystalline to the uncrystalliaable condition occur- ring. Treacle ( Thenaca, B. P.), Molasses, {Syrvfus Fusc-us, V. 8. P.), or Melasses (from Md, honey), chiefly results from the applica- tion of too much heat in evaporatmg the syrups of the sugar cane; it is a mixture of cane-sugar with uncrystaHizable sugar and color- ing-matter. lAcporias-TOOt {GlycvrrhtziE Radix, B. P.), contains a considerable quantity of unci^stalli sable sugar ( Glycyrrhizin).
Caramel. — Carefully heat a grain or two of sugar in a test-tube until it blackens ; the product is caramel or burnt sugar (the Saccharum Ustum of pharmacy). It is used as a coloring agent for gravies, confectioneries, spirits, and similar materials.
MannUe (CaH,,Oo) Boil manna with alcohol, filter, and
set aside ; mannite separates in colorless shining crystals or acicular masses, to the extent of from 60 to 80 per cent, of the manna.
Manna, B. P. and XJ. 8. P., is " a concrete saccharine exudation from the stem of Fraxinus Ornus and F. roiundifolia ; it is ob- tained by making incisions in the stem of the trees. It occurs in " stalactifomi pieces from one to six inches in length, and one or two inches in width, aiieven, porous, and friable, curved on one side, of a yellowish-white color, with a faintly nauseous odor, and a sweetish taste."
Mannite is an alcohol, the radical of which is sexivalent (0,Hj)'' 6H0 {Wanklyn). It ia cicely related to the sugars, glucose becom- ing mannite by action of nascent hydrogen : —
0„H,,,0„ + H, = O.lIi.Oj
eimoae. Hydrogen. Maniiitc.
Indeed, glucose itself ia probably an alcohol of another radical (C,H5)»'6HO. Mannite does not undergo vinous fermentation in contact with yeast. In is soluble in 5 times its weight of cold water.
id .y Google
AMYLACEOUS
Mucic Acdd (H^CjHsOj) and Sacfharic Acid (HjObHjOj) are two isomeric bodies formed by tlie action of dilute nitric acid on gum, sugar, and maonite.
QUESTIONS AND EXERCISES.
705. How are cane-sugar and grape-sugar analytically distin- guished ?
706. Describe the methods of extracting and purifying cane-sugar,
707. Mention the chief sources of cane-sugar.
708. Give chemical explanations of the different processes of bread-making.
709. How is milk-sugar obtained, and in what respects does it differ from other sugar ?
710. By what proce^ may starch be entirely converted into sugar ?
711. What is the difference between frni^sngar and honey ?
712. What is Oxymel ?
713. Describe the effect of heat on cane-sugar.
714. Describe the source and character of manna.
715. Give the latest view of the constitution of mannite.
716. Whence ai'e mucic and saccharic acids obtained ?
THE (JLTICOSIDES.
Source. — The Ulucosides are certain proximate vegetable princi- ples which, by ebullition with dilute acid, or other method of decom- position, take up the elements of water and yield glucose, accompa- nied byasecond substance, which differs in each case according to the body operated on. Twelve of the ^Incosides are of pharmaceutical interest, namely : Aloin, Amygdalin, Cathartic acid, ConvoJvulin, Digitalin, Elaterin, Guaiaein, Jalapin, Salicin, Santonin, Scammonin. Tannin, or tannic acid, is also a glucoside; it has been described among the acids.
Note o« Nomenclatv/re. — The first syllable of the names of glueo- sides and neutral principles generally are commonly given in allusion to origin ; the last syllable is in, which sufficiently distinguishes them
Aloin (0„H,60,„HsO).— This substance, first obtained by T. & II. Smith, occurs in minute crystals in that portion of aloes which is soluble in water. According to the experiments of Kosmann itseems to he a glueoside, the aqueous extract of aloes yielding, by ebullition with dilute acid, glucose and Aloesefic acid. The portion of aloes insoluble in water is also a glueoside ; for Kosmann by similar treat- ment obtained from it glucose, aloeresinic acid and aloeretinic acid. The aloes of Pharmacy {Aloe Barbadensis, B. F. and U. S. F., Aloe SocoPrina, B. P. and V. S. P., and Aloe Oapenais, U. S. P.), is an evaporated juice, doubtless much altered by the temperature to which it is subjected.
id .y Google
THE OLUCOSIPES. 341
Amygdalin (C^H„N0,„3H,0).~Thisia awhite crystal- line substance, existing in the bitter {Amygdala Amara, B. P.andU. S. P.)itiit not in the sweet aimond (Amygdala Dulcis, B. P. and U. S. P.). It is readily extracted by alco- hol from the cake left when the fixed oil has been expressed from bitter almonds. From the concentrated alcoholic so- lution ether precipitates the amygdalin.
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 bittev almonds ; add a grain or two of amygdalin, an odov of essential oil of bitter al- monds is at once developed. Bruise two or three bitter almonds and rub with water ; the vola.tile oil is again de- veloped (Oleum Amygdalae Amarse, U. S, P.).
Bitter Alm,ond-water (Aqua Amygdalw Amarse^ TJ, S. P.) is made by filtering a mixture of 16 minims of the oil witli 60 grains of carbonate of magnesium and 2 wiue-pints of distilled water.
The Bource of the h^'dride of benzoyl, or esaentiol oil of bitter al- mDDdB, in tiiese reactions is the amygclaliD, which, nnder the influ- ence of synaptase or em-ulsin, a ferment esisting in both bitter and sweet almonds, splits up into the csseotial oil, hydrocyanic acid, and glucose :—
Cs„H„NO„ + 2H,0 = C,H,OH + HON + 2C,il,,0^
Amygdaiin. Water, Hjdrfiie of Hydro.;!'- Gluooae.
bsBioyl. sale Bcld.
As each molecule of amygdalin yields one of hydrocyanic acid, a simple calculation shows that 17 grains {mixed with emulsion of sweet almonds) will be required to form one grain of real hydro- cyanic acid, a quantity equivalent to 50 minims of the dilute hydro- cyanic acid of the British Pharmacopteia.
Test. — The reaction between synaptase and amygdalin is applica- ble as a test of the presence of one by the addition of the other, even when mixed with much organic matter.
Ckerry-LauTehvater {Aqua Lawrocerasi, B. P., by distillation with water from Lawroceraai Folia, B, P.), contains hydrocyanic acid derived from a reaction similar to, if not identical with, that i net described. But the proportion of amygadalin or analogous body in cherry-laurel-leaves is most variable ; hence the strength of the water is highly uncertain. The preparation is worse than useless.
Caution. — Essential oil of almonds is highly poisonous. The purified oil or hydride of benzoyl is almost innocnons. Artificial oil of bitter almonds or nitrohenaol (CjHj(NOj) ) when taken in quantity has been known to produce death.
Cathaetic Aorn.- — " The glucoside acid that now is known to
confer on the Senna of Alexandria (Serena Alexandriana, B. P.),
Tionevely (Senna Indiea, B. P., Senna, U. 8. P.), and probably
39*
id .y Google
342 AMYLACEOUS AND SACCHARINE SUBSTANCES,
on American Senna {Gassta Marilandica, U. S. P.), its purga- tive property, has been named by its discoverers (Dragendorf and Knbly) Oatliartic acid. Its formula has been stated as Oibo&jjjNjSOjj, which, if true, accounts for its extreme stability. It is insoluble in water, strong alcohol, and ether, but enters readily into watery solu- tion when combined with alkaline and earthy bases. Its ammonium salts give browntoh floccuJent precipitates with salts of silver, tin, mercnry, copper, and lead. .Ajitimonial salts, tannin, yellow and ted prusaiates have no effect npon it. Alkalies, aided by heat, act destructively upon it. Boiled with a mineral acid it splits into a peculiar kind of glucose and an acid that has been named Cathar- togenic; its formula is said to be CujHjjjNjSOd. Cathartic acid, in a combined stale and of tolerable purity, is prepared by partially precipitating by strong spirit a watery infusion of senna, concen- trated to a syrupy state by evaporation in vacuo. The filtrate is now treated with a much larger bulk of absolute alcohol, and the precipitate thus obtained ia purified by repeated solution in water and precipitation by alcohol. To obtain the pure acid, advantage is taken of its colloidal properties ; the crude cathartate is dissolved in moderately strong hydrochloric acid, and subjected to dialysis on a diaphragm of parchment paper. The minimum dose of this pure acid was found to be about IJ grains, which cansed several stools with decided griping.
" The cartnartic combinations that I have made are, the cathar- tate of ammonium, prepared from cathartatc of lead by my original process, and the mixed cathartates, prepared according to Dragen- dort's method as ijiodifled by myself, 01 the former nearly pure salt, I have found SJ grains to pur^ fairly as to amount, but slowly as to time, and with considerable griping. Of the latter, 7^ grains purged violently with much griping and sickness, which eontinned through the greater part of the day. It obviously would be improper to combine senna with any of its metallic precipitants, should such be desired, which is not likely. It is here satisfactory to observe that the cathartate of magnesium is soluble, and that the old-fashioned black draught agrees with new-faahioned science." (Groves.)
Buckthorn juice (Rhamni Sucetts, E. P.) owes its cathartic pro- perties to a suDstance apparently identical with cathartic acid.
OoLOOTNiBiN (OBsHfaOjn?). — This substance is the active bitter and purgative prindpTe of coloey nth-fruit (Golocyrdhidia Pulpa, B. P., Goloeyrdhia, U. S. P.) : it is soluble in water and alcohol, but not in ether. By ebullition with acids it furnishes glucose and a resinoid body.
Convolvulin, — See Jalapih.
DiQiTALiN {C„H^O^. — This is an active principle of the Foxglove (Digitalis, B. P,), Boil a grain of digitalin {Digitalinum, B. P.) with sulphuric acid for some time; flocks of digitaliretin (CuH^jOj) separate, and glucoae may be detected in tbe liquid.
id .y Google
THE GI-UCOSIDES. 343
Properties.— TUgitalia ocQars "in porous mammillated masses or small scales, white, inodorous, and intensely bitter, readily soluble in spirit, but almost insoluble in water and in pure ether, dissolves in acids, bnt does cot form with thein neatral compounds ; its solu- tion in hydrochloric acid is of a faint yellow color, bnt rapidly be- comes green. It leaves no residue when burned with free access of air. It powerfiilly irritates the nostrils, and is au active poison."
Process. — The official process for the preparation of digitalin con- sists in dissolving the glucoside out of the digitalis leaf (Digitalis Folia, B. P. and U. S. P.) by alcohol, removing the alcohol by distil- lation, dissolving the residue iii water by the help of a small quantity of acetic acid, removing much of the color from the solution by ani- mal charcoal, neutralizing most of the acetic acid by ammonia, precipitating the digitalin by tannic acid, (with which it forms an maoluble compound), washing the [ffecipitate, rubbing and heating it with spirit and oxide of lead (which removes the acid in the form of insoluble tannate ot lead), agam decoloiiarag by animal charcoal, evaporating to drynpsa washing out impurities still remaining by ether, and drying the residu'*! digitalin In this form digitalin is uncrystallizable.
Pure Digitalin. — On treating commercial digitahn with chloro form only an inert substance remains nndissohed The dilution yields pure digitalin on eiaporatiun it may he crystallized from spirit in radiating needles (Nativelle ) The therapeutic power of the pure substance has not been determined
Elatebin (C^HjsOj) — Boil elateimm (mateiuim,B P and TJ. S. P.), the dried eediment fiom the juice ot the sqairting-cacambeTfrait (UcbaliiFrucfuSf'B.'P.), in asmall quantity of spirits of wine, and filter; fibrous and amy- laceous matter remain insoluble, while elaterin and resin are dissolved. The filtrate, concentrated and poured into a warm solution of potash, yields, on cooling, crystals of elaterin, resin being retained by the alkali. It is purified by recrystallization from spirit. Boil elaterium in dilute sulphuric acid for an hour or two, filter, and test the clear liquid for glucose ; a reddish precipitate of cuprous oxide falls. This reaction is readily obtained with elaterium, but not always with elaterin ; hence probably the latter is not a true glucoside.
Elaterin is the active principle of the so-called elaterium. Elate- rium occurs " in light friable slightly incurved cakes, about one line (j'e inch) thick, greenish-gray, acrid and bitter ; fracture fluely granu- lar." Grood specimens of this drug should yield, according to the British Pharmacopoeia, not less than 20 per cent, of elaterin by the above process. ESaterium is sometimes adulterated with chalk and other substance.
GuAiACiN. — Resin of guaiactim {Guaiaci Sesina, B. P. and U. S. P), an exudation from the wood ( Guaiaci Licj-
id.y Google
844 AMYLACEOUS ANT- SACCHARINE SUBSTANCES.
num, B. p. and TJ. 8. P.) of Guaiacum officinale, is probably a mixture of several substances, among which are Ouaia- retinio acid (Cs„HjqO,) (Hlasiwetz) and Cfuaiacin, s, gluco- side. On boiling guaiacum-resin with dilute sulphuric acid for some time, glucose is found in the liquid, a green resinous substance (guaiarelin) remaining insoluble (Kos- mann). Most oxidizing agents, and even atmospheric air, especially under the influence of certain organic sub- stances, produce a blue, then green, and finally a brown color, when brought into contact with an alcoholic solution of guaiacum-resin.
These effects are said to be due to three stages of oxida- tion (Jonas). They may be observed on adding the solu- tion to the inner surface of a paring of raw potato.
Jalapin fCj,H„0,j) AND CoNVOLVi:LiN(C^HiaO,a). — Ac- cording to Keyser and Meyer, jalap-resin contains two distinct substances — convolvnlin, chiefly obtained IVom Mexican male jalap, and jalapin, most largely contained in the true jalap ; the former is soluble in ether, the latter insoluble. Boil jaiap-resin with dilute sulphuric acid for some time and filter ; a substance, which is probably a mix- ture of jalapinol (C^Hj^O,) and convolvulinol (C„'SJi^), separates ; and glucose may be detected in the clear liqiiid. (It is to be regretted that the authors transpose the above names, terming the old well-known jaiapin convolvuliu.)
Jalapic acid. — This is contained in the portion of jalap- resin soluble in ether. It may also be obtained from jalapin by ebullition with allialies: —
Jnlspic i>cld.
Jalap^esin (Jalapm Besina, B. P. and TJ. S. P.) is ob- tained by digesting and percolating jalap tubercles {Jalapa, B. P. and TJ. S. P.) with spirit of wine, adding a little water, distilling off the spirit, pouring away the aqueous portion which contains much saccharine matter, and wash- ing and drying the residual resin. The tincture is some- times decolorized by animal charcoal, and 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 speci- men should be powdered, digested in turpentine, the mixture filtered.
id .y Google
THE GLUC09IDES. 345
aod the filtrate eyaporated ; no residue, or not more than yielded ty the turpentine itself, shonld be obtained,
Salicin (0[3H„0,), — This substance is contained in and easily extracted from willow-bark.
Tests. — 1. To a small portion of salicin placed on a white plate or dish add a drop of strong sulphuric acid ; a deep- red color is produced.
2, Boil salicin witli dilute sulphuric acid for some time; it is converted into saligenin {0,HgO^) and glucose.
Examine a portion of the solution for grape-sugar by the copper test.
3. To another portion of the liquid, carefully neutral- ized, add a pcrsalt of iron ; s. purplish-blue color is pro- duced, due to the reaction of the saiigenin and the ferric salt.
4. Heat a mixture of about 1 part of salicin, 1 of red chromate of potassium, \\ of sulphuric acid, and 20 of water in a test-tube; a fragrant characteristic odor is evolved, due to the formation of hydride of salicyl {C,Hj O^H), an essential oil identical with that existing in meadow-sweet (Spireea ulmaria) and in heliotrope.
20,Hs03 + Oj = 2C,H50,H + 2iifi
Sitl^eniii. Olygen. HytLride of Waler,
Santonin (Oj^HijOj). — This substance is a weak acid, insoluble in ammonia, but fonuing a soluble calcium, salt. Prom a solution of santonate of calcium the santonin is precipitated by aoids. Boiled for some time with dilnte sulphuric acid it yields 87 per cent, of an insoluble resinous substance (santomretin) and glucose (Kosmann). Santonin {Santoninv/m, B. P. and XT. S. P.) is official.
Process. — The process for its preparation consists in boiling san- tonica, B. P. and U. S. F. (the anexpanded flower-heads of an unde- termined species of Artemisia) ■with milk of lime (whereby santo- nate of calcium is formed), straining, precipitating the santonin or santonic acid by hydrochloric acid (acetic acid, U. S. P.), washing with ammonia to remove resin, dissolving in spirit and digesting with animal charcoal to get rid of coloring-matter, setting the spirituous solution aside to deposit crystals of santonin, and purifying by re- crystalliaation from spirit. (Mialhe).
Saponin (OuH^O, ?) is a peculiar glucoside occurring in Soap- wort, the root of the common Pink, and many other plants : its so- lution in water, even though very dilnte, froths like a solution of soap. Pereira considered smilacin, one of the principles of the supposed activity of Sarsaparilla (Sar^ce Radix, B. P., SarsaparUla, U. S. P.), to be closely allied to, if not identical with, saponra.
id .y Google
346 AMYLACEOUS AND BACCHARINE SUBSTANCES.
Saponin is also met with, in the root of Polygala Senega {Senegce Radix, B. P., Senega, U, S. P.), though the active principle of senega is said to reside in pdlygalic add, probably a glncoside derivative of saponin.
SOAMMONIN CCsjH^jOja). — Boil resiii of seammony (Saam- moniee Itesina, B. P. and TJ. S. P.) with dilute suipliuric acid for some time ; glucose may then lie detected in tlie liquid, a resinous acid termed scammoniol (C^fi^^O^ ?) being produced at the same time.
Natural seammony (Seammoniv,m, B. P. and U. S. P.) is an exu- dation from ineiBions in the living root {Seammonia Radix, B. P.) of Convolvulus Seammoma. It contains from 10 to 20 per cent of gum. The British official resin of seammony contains n gnm and is made by digesting the root in spirit, adding water d 11 g ff the alcohol, and washing the residual resin with hot i ate t II f e from gum.
The TJ. S. P. process consists in exhaosting seammony al I I recovering the latter by distillation, treating the residu th wat and drying the separated resin.
QUESTIONS AND KXEECISES. in. Define glucosides, and mention those of pharmaceutical in-
718. What is Aloes, and what crystalline principle may be ob- tained from it ?
719. Draw out an equation illustrative of the development of Oil of Bitter Almonds.
720. To what does Cherry-Laurel-water owe activity? Is the preparation trustworthy?
721. Mention the active principle of Senna.
722. By what process is the glueoside of the purple foxglove pre- pared !
723. State the circumstances under which Guaiacum-Ecsin and Jalap-Eesin yield glucose.
724. Mention a test for guaiaeum-resin.
725. How may the adulteration of jalap-resin by rosin bo de- tected ?
726. Enumerate the tests for Salicin.
727. How is Santonin officially prepared !
728. Name sources of saponin.
729. WhatisthedifferencebetweenScammonyand Eesinof Scam-
id .yCoOglc
ALCOHOL. 347
ALCOHOL AND ALLIED BODIES. ALCOHOL.
Formatton of Alcohol. — Ferment two or three grains of sugar by dissolving in a test-tnbe fnll of water, adding a little yeast (Oere- vist(e F&rmentum, B. P., Fermentum, U. S. P.), or piece of the so- called German or dried yeast, and setting the whole aside in a warm place at a temperature of 70^ or 15°; carbonic aeid gas 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 large quan- tities (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, soda, or potash, to neutralize any acetic acid, and decompose ethereal salts, and again distilled till one half has passed over ; the product is dilute spirit of wine. It may be still further concentrated or rectified by repeating this process of fradtonal die- iillatiim.
Both cane-sugar and grape-sugar yield alcohol by fermentation, the cane-sugar probably always passing into grape-sugar before the production of alcohol commences.
C-H,,0. = 203sH0 + 2C0-
Grape-aD^r. Afcohol. Carboalo '
aoi* gsa.
Hence the spirit of the various tinds of wine, beer, and liqueurs, such as Orange Wine ( Vinvan Auraniii, B. P.) made " by the fer- mentation of a saccharine solution, to which the fresh peel of the bitter orange has been added ;" Sherry Wine ( Vmu-m Xsricum, B. P. and U. 8. FA the fermented Jnice of the grape.
Port Wine { Kiniim PoHertse, U. S. P.), Whiskey [Spiritus Fru- menbi, U. 8. P.), containing irom 48 to 56 per cent of pure alcohol; Spirit of Myrcia, or Bay Rum, {Spirit-as Myrcioi, U. S. P.), pre- pared by distilling mm with leaves of Myrda acris, and others.
Varieties of €deoltoL—The weak spirit concentrated by distilla- tion till it contains 84 per cent, by weight of pure alcohol is an or- dinary article of commerce; its specific gravity at 6(P is 0.8382. This is common Spirit of Wine, the Sptrittts Sectificattts of the British Pharmacoptfiia. Alcohol, IT. 8. "P., has sp. gr. 0.835; Alco- hol Fortius, F. S. P., sp. gr. 0.817. The official Proof Spirit* (Spiritus Tew-uior, B. P.) contains 49 per cent, by weight of alcohol, and is made by diluting 100 volumes of Eectified Spirit with water until the well-stirred product measures 156 volumes. Sixty volumes of water will be required for this purpose, the liquids occupying less
* Proof spirit is so termed from the fact that in olden times a proof of its strength was supposed to be afforded by moistening a smull quantity of gunpowder and setting lightj^> the spirit ; if it fired the powder it was said to be " over proof ;" if not, " under proof." The w«!ikeEl; spirit that would stand this test was what we sboa)d now de-
id, Google
3i8 ALCOHOL AND ALLIED BODIKS.
bulk aft«r than before admixture. In the language of the Excise authorities tlie rectified spirit of the Pharmacoposia wonld he de- acribed as "56 per cent, over proof" (56 percent. 0. P.) ; thatislOO volumes cODtaiaB as much alcohol as is present in 156 volumes of proof spirit. Obviously, proof spirit may be made by diluting with water rectified spirit of any other strength than that mentioned above. Thos 100 flnidouncea of a spirit of "seventy over proof" maybe diluted to no, or the same quantity of a spirit of "fifty over proof" may ha diluted to 160, and so on. The specific gravity of proof spirit at 60'^ is 0.920. [Alcohol Dilutitm, U. B. P., has sp. gr. 0.941.)
Composition of Alcohol. — Alcohol, by quantitative analysis, is found t« contain the elements carbon, hydrogen, and oxygen in the following proportions: —
Cerdistm.cd composition of Alcohol.
Carbon .... 52.174 Hydrogen . . . 13.043
100.000
From these numbers a formula is obtained in the usual way. Thus, on dividing these figures by the atomic weights of the respective elements {C=12, H=l, 0=16), and reducing the products to the simplest whole numbera, alcohol will be found to contain two atoms of carbon to every sis of hydrogen and to every one of oxygen, and its possible or empirical formida to be OjEjO.
GottstiiiUion of Alcohol, — There is good reason to believe that alcohol is the hydrate of a basylous radical ei%i (0,Hj or Bt) ; hence we derive the rational formida 0,H,HO or BtHC).
Saits of Ethyl. — Alcohol is, then, a body analogous in constitn- tion t« hydrate of potassium (KHO) ; and there are other compounds of ethyl analogous in constitution to ordinarv inorganic salts, aach as those of potassium. The oxide of ethyl (EtjOJ is common ether; the nitrate of ethyl (BtNOJ is the body which, dissolved in spirit of wine, constitutes " sweet spirit of nitre;" the acid sulphate of ethyl (BtHSOj), or snlphethylie or sulphovinic acid, is a liquid met with m the preparation of ether. The iodide (Etl), hydride (EtH), ace- tate (EtA) and other salts are of considerable chemical interest, but not used in medicine.
Absolute or Real Alcohol. — (C,HjEO) may be prepared from spirit of wine by removing the water which the latter contains. This IS accomplished, partially, by the agency of carbonate of potas- sium and finally and entirely by recently burned quicklime. In operating on, saj', one pint, IJ ounces of dried carbonate of potas- sium IS placed in a bottle that can be well closed, and frequently shaken miring two days with the spirit. Meanwhile, about half a pound of good quicklime, if sot already at hand, is made from 10 or 11 ounces of slaked lime by heating to redness in a covered crucible for hair an hour. The spirit having been decanted from the denser
id, Google
ALDEHYD. 349
aqueous soluliou of carbonate of potassium anil placed in a quart flask, retort, or tin can, the lime, as soon as cold, is added, and the whole occasionally shaken during a. da^. The vessel is now placed in a Baucepaii or oilier bath containing water, quickly connected with a condenser (in the jcase of tiie flask or can by a bent Inbe and cork previously prepared ; for absolute alcohol mast not be exposed to air, or water in the form of moisture will be rapidly reabsorbed) and heat applied to the bath. Eejecting the first ounce or ounce and a half, as likely ta contain traces of moisture absorbed from the air or apparatus, continue distillation until nothing more passes over, the water in the bath being kept just below the boiling-point (abont 200° F-). T.'hrae details are those of the British Fbannaccpceia. Specific gravity 0.7938.
Tests.- — There are no specific tests for alcohol when mixed with complex matters. It is, however, easily isolated and concentrated by fractional distillation, and is then recogniBable by conjoint physi- cal and chemical characters. Thoa its odor and taste are charac- teristic; it ia lighter than water, volatile, colorless, and, when tolerably strong, inflammable, burning with an almost non-luminous flame; it readily yields aldehyd (see below) and acetic ether (vide p. 248), each of which has a ch^aeteristiG odor; lastly, in presence of hot acid, alcohol reduces red chromate of potassium to a green salt of chromium.
Teats of purity. — Oil or resin fei jwecipitated on diluting spirit of wine with distilled water, givioK an opalescent appearance to the mixture. The specific gravity shoald be 0.838. Fusel oil, aldehyd, and aldehydic acid are detected by nitrate of silver {vide Index, "Alcohol"). Water in absolute alcohol may be detected by adding to a small quantity a little highly dried sniphate of copper, which becomes blue (OuSOj,5HjO} if water is present, bnt retains its yellowish-white anhydrous character (CnSO^) if water be absent,
Aldehyd (CjH^O). — Place together, in a capacious test- tube, or a flask, spirit of wine, black oxide of inauganese, sulphuric acidj and water, and. gently warm the mixture ; aldehyd (alcohol deht/drogen&tus), a highly volatile liquid, is immediately formed, and its vapor evolved, recognized by its peculiar, somewhat fragrant odor. Adapt a cork and rather long bent tube to the test-tube, and let some of the aldehyd slowly distil over into another test-tube, the con den sing-tube being kept as cool as possible. Set the distillate aside for a day or two ; the aldehyd will have nearly all disappeared, and acetic acid be found in the tube. Test the exposed liquid by litmus paper ; it will be found to have an acid reaction : make it slightly alkaline by a drop or two of solution of carbonate of sodium, then boil to remove any alcohol and aldehyd present, add sul- phuric acid, and notice the characteristic odor of the acetic acid evolved.
id .y Google
350 ALCOHOL AND ALLIED BODIES.
These experimeiita will enable the process of acelification described ill connection vfith acetic acid to be more folly nnderatood. Pure diluted alcohol is not oxidized bj exposure to air ; but in presence of fermentive matter, or vegetable matter undergoing decay or change, it is oxidized first to aldehyd and then to acetic acid.
In the above process the black oxide of manganese and sulphuric acid furnish nascent oxygen : —
2MtiO, + 2HS0, = 2MnS0, + 0, + 211,0
One molecule of the nascent oxygen then acts on two molecules of the alcohol, just as the oxygen of the air acts on the alcohol in fer- mented infusion of malt, heer, or wine, giving aldehyd ; —
2O5H5O + O, = 20,H,0 + 2H,0 Alcohol, OsygoD. AMehyfl. Water,
The aldehyd rapidly, even when pure {more rapidly when impure), absorbs osygen antf yields acetic acid;—
2C^Tlfi + Oj = 2C5H,05 Aldohyd. Oijgen. Acetic acid.
Spirit 1^ French WinelSmritus Vini Gallici.'B.'P. andU.S,P.) or Brandy is a colored and flavored Yftriety 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 is commonly deepened by the addition of bnrnt sugar. lis taste is due to the volatile flavoring constituent of the wine, often increased by the addition of artificial es. It should contain from 48 to 56 per cent, of alcohol.
QUESTIONS AND EXEECISES.
730. "Write a few sentences on the formation, purification, and concentration of alcohol, and explain the difference between Kectified Spirit, Proof Spirit, and Absolute Alcohol.
731. What quantity of water must be added to one gallon of spirit of wine, 56 degrees over proof, to convert it into proof spirit?
732. To what volume must 5 pints of spirit of wine of 53 degrees be diluted before it becomes i>roof spirit!— .dres. 7 pints, 13 ounces.
733. State the specific gravity of proof spirit.
734. Show how the formula of alcohol is obtained from its centesi- mal composition ; —
Carbon 52.174
Hydrogen 13.043
Oxygen 34.783
100.000
735. Give the formulse of some of the salts of ethyl.
736. By what processes may pure hydrate of ethji be obtained?
737. Enumerate the characters of alcohol.
id .y Google
ETHYL 10 ETHER, 351
138. Mention a chemical teat to distinguisli rectified spirit from absolute nlcobol.
739. From the formula of aldehyd calculate its compositioa in 100
740. "What is the relation of aldehjd to aloohol and to acetic acid f
741. Whence is braady obtained, and to what are due its color and flavor !
Formula 0,H,„0, or (C,H,),0, or Et,0.
Experimental Process.— Into a capacious test-tube put a small qnantity of spirit of wine and about half its bulk of sulphuric acid, mix, and gently warm; the vapor of ether, recognized by its odor, is evolved. Adapt a coi-k 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 give ether; and this operation may be repeated many times.
On the large scale, and according to the following official process ^Jither, B. P. and U. S. P.), the addition of alcohol, instead of being intermitting, is continuous, a tube conveying alcohol from a reservoir into the generating-vessel. Mix 10 fluidonncea of sulphuric acid with 12 fluidonnces of rectified spirit in a glass flask capable of con- taining at least two pints, and, not allowing the mixture to cool, connect the flask by means of a bent glass tube with a Liebig's con- denser, and distil with a heat sufficient to maintain the liquid ia brisk ebullition. If a thermometer be used the temperature may be still more carefully regulated— between 284P and 290° F. As soon as the ethereal fluid begins to pass over, supply fresh spirit in a continuous stream, and in such quantity as to equal the volume of the fluid which distils over. For this purpose use a tube furnished with a stopcock to regulate the supply, connecting one end of the tube with a vessel containing the spirit suppjjrted above the level of the flask, and passing the other end through the cork of the flask into the liquid, When a total of 50 fluidounces of spirit has been added, and 43 flnidonnees of ether have distilled over, the process may be stopped.
To partially purify the liquid, dissolve 10 ounces of chloride of calcium in 13 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 dis- til it with a gentle heat until a glass bead of specific gravity 0.735 placed in the receiver begins to float. The ether and spirit retained by the chloride of calcium and by the residue of each rectification may be recovered by distillation and used in a subsequent operation,
id .y Google
352 ALCOHOL AND AI-LIET BODTKS.
Explanation of Process. — On the addition of snlphuric acid to alcohol in equal volumes, one molecule of each react and give a molecnle of snlphethylic acid and one of wafer ;—
EtHO + H,S,0 = EtHSOi + H^O
alcohol. SDlphDiiD SulFbethjrlic Wnliir.
More alcohol then gives ether and sulphuric acid tiy the reaction of one molecule of the alcohol on one of salphethjlic acid ; —
i,0 + H^O, ler. SulphucTo
The water of the first reaction and the ether of the second distil over, while the snlphurie acid, as fast as liberated, ia attacked by alcohol and reconverted into snlphethylic acid,
EtHO + H,SO, = BtHSO, = n,0
Alcuhul. Sulpburlii Sulpbetlirllc Water.
SO that the sulphuric acid originally empioycd finally remains in the relcirt in the form of snlphethylic acid. The effect, however, of a small qnantity of sulphuric acid in thus converliug a large quantity of ttlconol into ether is limited, secondary reactions ocenrring to some extent after a time.
Properties.— V'OTt ether is gaseous at temperature above 95° F. ; hence the condensing-tubes employed in its distillation must be kepi as cool as possible. At all ordinary temperatures it rapidly evapo- rates, absorbing much heat from the surface on which it is placed. A few drops evaporated consecutively from the back of the hand produce ^at cold ; if blown in the form of spray, the cooling effect ts so rapid and intense as to produce local anaesthesia. Its vapor is very heavy, more than twice and one-half that of air, and in a still atmosphere will flow a considerable distance along a table or floor before complete diffusion occurs ; the vapor is also highly inflam- mable ; hence the importance of keeping candle and other names at a distance during manipulations wi(]i ether.
Purification. — To imitate the process of partial purifica- tion above described, add to the small quantity of ether obtained in the foregoing operation a strong sohition of chloride of calcium and a Httlo slaked lime; the latter absorbs any sulphurons acid that may have been produced by Beeondary decompositions, ■while the former absorbs ■water; on shaking the mixture and then setting aside for a minute or tv7o, the ether will be found floating on the surface of the solution of chloride of calcium.
This ether, redistilled until the distillate has a sp. gr. not higher than 0.735 (0.750, U, S. P.) and boiling-point not higher than 105° F., is the ether of the British Pharmacopceia. It still contains about 8 per cent, of alcohol. The latter may be removed by well shaking
id .y Google
NITROUS ETHEH. 353
the ether with half of its balk of water, setting aside, separating the floating ether and again shaking it with water ; alcohol is thus washed out. This washed ether containing water (for water and ether are to some extent soluble the one in the other ; 50 measures agitated with an equal volume of water are reduced to 45 by an absor|)tioa of 10 per cent.) is next placed in a retort with solid chlonde of calcium and a little caustic lime, and once more distilled ; pure dry ether {Mlker Bams. B. P., ^ther Forttor, U. S. P.) results. Sp. gr.not exceeding 0.120 (0.728, U, S. P.).
Spiritiis JEtkeris, B. P., is a mixture of common ether {jEllier, B. P.) with twice its hulk of rectified spirit.
KITaOTTS ETHER, OS. ITITKITE OE ETHYL.
Pormula EtNO,. Process. — To a third of a test-tubefiil of rectiflecl spirit add about a teuth of its balk of sulphuric acid, rather more of nitric acid, and some copper-wire or turnings, and warm the mixture as soon as ebullition coraroences, the vapor of nitrous ether is evolved, recognized by its odor, A long bent tube, kept cool, may be adapted by a per- forated cork to tiie test-tube, and thus a few drops of impure nitrous ether be condensed and collected.
Tke above process conducted on a larger scale, with definite quantities of materials, temperature regulated by a thermometer, and a well-cooled condenser, is the official (Redwood's) process for the preparation of a concentrated solution of nitrous ether in spirit; diluted with nearly three times its bulk of rectified spirit it forms the "sweet spirit of nitre" (Spiritus Mtheris Nttrosi, B. P. and U. S. P.) of pharmacy.
"Take of
Nitric Acid 3 fluidounces,
Sulphuric Acid 2 fluidounces,
Copper, in fine wire (about No, 25) 2 ounces,
Eectified Spirit a sufBeiency.
" To one pint of the spirit add graduaUy the sulphuric a^id, stir- ring them together; then add, in the same way, two and a half ounces of the nitric acid. Put the mixture into a retort or other suitable apparatus, into which the copper has been introduced, and to which a thermometer is fitted. Attach now an etfioient condenser, and, applying a gentle heat, let the spirit distil at a temperature commencing at 170^ and rising to 175°, bnt not exceeding 180°, until 12 fluidounces have passed over and been collected in a bottle kept cool, if -necessary, with ice-cold water; then withdraw the heat, and, having allowed the contents of the retort to cool, introduce the remaining half ounce of nitric acid, and resume the distillation as before, until the distilled product has been increased to 15 fluid- 30*
id .y Google
354 ALCOHOL AND ALLIED BODIES.
ounces. Mis this with two pints of the rectified spirit, or as much as will make the prodnct correspond to the tests of specific gravity and percentage of liquid separated by chloride of calciwn {viae infra). Freserve it in weilriilMied vessels.
Disregarding secondarj; products, the following equation probably represents the decompositions that occnr in the ogeratioa. The main point in the reaction is the reduction of the nitric to the nitrons radical by the indirect agency of the copper.
EtHO + HNO, + H,80. + Ou = EtNO, + 2X1,0 + CnSO,
Alcohul. Kltric Sulphuric Copper. Wltrous Walet. Bulph»[e of
Properties. — Spirit of Nitrous Ether " is transparent and nearly colorless, with a very slight tinge of yellow, mobile, inflammable, of a peculiar penetrating apple-like odor, and sweetish cooling sharp taste. Specific gravity, 0.845. It effervescw feebly, op not at all, when shaken witii a little bicarbonate of soda" (showing absence of appreciable quantities of free acid).
Test. — The nitrous radical may be detected by adding sulphate of iron and sulphuric acid to some of the spirit of nitrous ether, a brown or black compound being produced, already explained in connection with nitric acid (p. 231}.
Test of strength. — To some of the official Spirit of Nitrous Ether add twice its bulk of a saturated solution of chloride of calcium and mix the liquids; on setting aside, nitrous ether will rise to the surface. If the spirit of nitrous ether he of official strength, not less than 2 per cent, of its volume will thus separate, indicating the pre- sence of 10 per cent, of the ether, 8 per cent, still remaining dissolved. A graduated tube is obviously most convenient for this purpose.
Spiritus Mtheris Nitrosi, TJ. S. P., is made by the old process of distilling a mixture of alcohol and nitric acid, and redistilling from carbonate of potassium, which retains any traces of nitric acid. Sp, gr. 0.83t. Strength ia nitrons ether 4.3 to 5 per cent.
Iodide of Ethyl. (EtI) may be prepared bj' mixing amorphous phosphorus with absolute alcohol and then adding iodine.
5EtH0 + PI, = 6EtI + H,PO, + H„0
AlcohoL loiildeof lodfdaof PHosphorLc W&tet.
phQspliorns. ethyl. acid.
The reaction at first proceeds rapidly, and ia complete after the mixture has been set aside for a few hours. The iodide of ethyl may then be isolated by careful distillation, freed from any excess of iodine by washing with a very small quantity of solution of potash or soda, washed with
id .y Google
■water, dried over chloride of palcium, and again distilled. It should be kept in a dark place, as light favora decompo- sition and liberation of iodine.
Ethyl. — This gaseous radical, (C^HJ^ or Et„ is obtained on digesting together at about 250° F., in a etroug scaled tube, dry fteshly granulated zinc with iodide of ethyl (Frankland).
Zn + 2BtT = ZnT + Et,
On cautiously opening the tube the ethyl escapes, and may be ignited or collected over ■water. There remains with the iodide of zinc a body termed by Frankland zinc-ethyl (ZnEtj); it is a spontaneously inflammable liquid, but may easily be distilled and otherwieo manipulated if a few sim- ple precautions he observed. If water bo allowed to flow down the tube, the aolid compound of iodide of zinc and zinc-ethyl will be decomposed, a gas, hydride of ethyl (EtH), resulting, which also may be inflamed or collected over water; —
ZnEt, + Sn^O = Zn2H0 + 2EtH.
QUESTIONS AND BXEEOISES.
742. Describe the official process for the preparation of Ether, giving equations.
743. Offer a physical explanation of the mode of producing local anfesthesia.
744 How is commercial ether purified?
745. Explain Redwood's process for the preparation of "sweet spirit of nitre."
746. Give the properties of spirit of nitrous ether.
747. By what method is the strength of "aweet spirit of uitre"
OTHER ALCOHOIj BADICAIiS AND THEIR SAIiTB.
What has been stated concerning' the chemistry of c'thyl and its compounds may be applied to other radicals known to exist, some of the uomponnds of each of which are of common occurrence. These baaylous radicals are closely related to each other, to hydrogen, and to the metab. Starting from hydrogen, their formulie may be built e additions of CH,, thus: —
id .y Google
356
ILLIED ItODlES.
Hydrogen
Methyl CH,,
Ethjl Cjii,, or Et
Propyl (or Trityl) 0,H;, or Pr
Bntyl (orTetryl) 0,11,, or Bii
Amyl (j^^liii or Ay
Caproyl (or Hexyi) O^H,,, or Cp
The above list is an illustration of an homologous series (from ^ibi, homos, the same, and xdyo{, logos, description) of compounds. It will be observed that the relation of the number of hydrogen atoms to carbon is twice as many nith one added ; hence the series is often termed the C*H„4, series (n^any number). The oxides of these radicals are known as ethers, theit hydrates alcohols, their compounds with the acetic and similar acidulous radicals ethereal salts. Every alcohol furnishes a body corresponding to the aldehyd of spirit of wine, the class being termed alaehifds; each also yields an acid cor- responding with acetic acid. Any one of these classes constitutes an homologous series. Or, taking the hydride, oxide, hydrat«, a«id, of any sin^e radical, we get a heterologous (tVfpof, heteros, another) series of compounds. Hydride of methyl (MeH or CH,H) is ordi- nary marsh-gas, fire-damp, or light carbvrettecl hydrogen; it is a diluent or non-lominiferoua constituent of ordinary coal-gas to the extent of 30 to 40 per cent.*; formic acid, the acid of the methyl series; fiiiiyrjc acid, the acid of the butyl seri^; sulphoevanate of butyl, the essential oil of horseradish; valerianic acirf, the acid of the amyl series.
Homologous and Heterologous Series of the C„ H,,, +j Radicals.
(OsHii)!
OHjE
C3,H aH.H C,H„H
OeHiiH
Ac.
(C H. ),,0
(C.H, ),0
(f 43. ,0
(CsH„),0
&c.
0 H, HO OjH. HO C.H- HO G,H,HO 0,H,,HO
CH.O? 0,H, 0 ChH„0 04H,0 O^Hi„0
CH.O- 0,H, 0, C,H- 0, C.H. 0.
* Coal-gas. — The other diluents, or vehiolas for the illuminating constituents, of ooal-gas are hydrogen (40 to 50 per cent.) and oarbonio oxide (6 to 7 per cent.). The illnminatiog constituents are olefiant gas (p. 364) and its homologaes, existing to the extent of from 5 to T per cent. The impurities are nitrogen, air, carbonio aoid, bisulphide of carbon CSj (a volatila liquid easily made from its elements), and other badly smelling sulphur compounds. Upwards of Sfty distinct cliemioal substances have been obtained from the solid, liiinid, and gaseous products (it the destruciive distillation ot coal.
id .y Google
M E T H Y 1 1 C .
QUESTIONS AND EXERCISES.
750. Mention several radicals homologous with ethyl, aad give their formul«.
151. Define ethers, hydrides, alcohols, ethereal salts, aldehyds.
752. What is the difference between homologous and heterologous
753. Give the systematic name ot fire-dnmp.
754. Enumerate the chief conatitnenta of coal-gas.
755. Stat« the foraiiilEB of formic, butyric, and valerianic acids.
756. Write the formnlte of butyl, its hydride, ether, alcohol, alde- hyd, and acid.
MYTHYLIC ALCOHOL.
Mbtrylic Alcosol (CH,H0, or MeHO), Wood-Spibit, or Py- ROIYUC 8pieit, is a product of the destructive distillation of wood. Spirit of wine containing 10 per cent, of wood-spirit constitutes or- dinary methylated spirit, a spirit issned duty free, for the nee of manufacturers, the methylic alcohol not interferiDg with technical applications. From its nauseous taste and odor, however, it cannot take the place of gin, brandy, or other spirit; hence, while industry is benefited, intemperance is discouraged and the revenue not in-
DetecUon of Methylic Alcohol in presence of Ethylie Al- cohol.— Three or four methods have been proposed for the detection of methylated spirit in various liquids ; that open to least objection is bj J. T. Miller, For the application of tbe tebt to tinctuieu and similar spirituous mixtures, some oi the ipuit is fiist separated by distilling off a diichm 01 so fiom ^bout half an ounce of the liquid placed in a amill flask oi test tube haviug along bent tube at- tathed Into a eimiKi apparatus put 30 grains of pow- deied led chiomite of potassium, half an ounce of water, 25 minims of stiong sulphuric acid, and 30 or 40 minims of the spiiit to be tested Set the mixture aside for a quar- tei of an hour and then distil half a fluidounce. Place the distillate m a small dish, add a rery slight excess of carbonate of sodium, boil down to about a quarter of an ounce, add enough acetic acid to impart a distinct but feeble acid le'vction, pom the liquid into a test-tube, add a grain of nitrate of silver dissolved in about 30 drops 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 methylic alcohol ; but if a copious
id .y Google
358 AT.COITOI. ANB ALLIED BODIES.
precipitate of dark-brown or black metallic silver separates, and tbe tube, after being rinsed out and filled with clean water, has a distinct film of silver, which appears brown by transmitted light (best seen by holding it against white paper), the spirit is methylated.
Explanation. — This test depends for its action on the reducing- powers of formic acid. lu the above operation tie ethjlic alcohol becomes oxidized to acetic acid (the natural acid of the emj\ series^, which does not reduce silver salts, a miniile quantity only of formic acid being produced, white the methylic alcohol yields formic acid (the natoral acid of the methyl series) in a comparatively large quantity. Aldehyd, which is a!so a reducing agent, is simultaneously produced, but removed in the subsequent ebullition with carbonate of sodium.
Methylated Sweet Spirit of Nitre. — The preparation of spirit of nitrous ether from methylated spirit is illegal, but, nevertheless, occasionally practised. For the detection of methylic alcohol in this liquid, Mr. Miller suggests the following modification of the above process.
Shake about an ounce of the sample with 20 or SOgi'aina of anhydrous carbonate of potassium, and, if needful, add fresh portions of the salt until it ceases to be dissolved, then pour off the supernatant spirit. This serves to neutralize acid and to remove water, in which some sam- ples are remarkably rich. Introduce half a fluido\ince of tbe spirit into a small flask; add 150 grains of anhydrous chloride of calcium in powder, and stir well together; then, having connected the flask with a condenser, place it in a bath of boiling water, and distil a fluidrachm and a half, or continue the distillation until scarcely anything more comes over. The operation is rather slow, but needs little attention, and should be done thoroughly. The distillate contains nearly the whole of the nitrous ether and other interfering substances. Now add to the contents of the flask a fluidrachm of water, and draw over the half drachm of spirit required for testing. Add to it the usual oxidizing solution composed of 30 grains of red chromate of potassium, 25 minims of strong sul- phuric acid, and half an ounce of water ; let the mixture stand a quarter of an hour, then distil half a flaidounce. Treat the distillate with a slight excess of carbonate of sodium, boil rapidly down to two fluidrachms, and drop in, cautiously, enough acetic acid to impart a faint acid reaction ; pour the liquid into a test-tube about three-quar-
id.y Google
CHLOROFORM. 359
ters of an inch in diameter; add two drops of diluted acetic acid, and one grain of nitrate of silver in half a drachm of pure water; apply heat, and boil gently for two minutes. If the spirit is free, from methylic alcohol the solution darkens and often assumes transiently a purplish tinge, but continues quite translucent, and the test-tube, after being rinsed out and filled with water, appears clean or nearly ao. But if the spirit contains only 1 per cent, of methylic alcohol the liquid turns first brown, then almost black and opaque, and a film of silver, which is brown by transmitted light, is deposited on the tube. When the sample is methylated to the extent of 3 or 4 per cent., the film is sufiftciently thick to form a brilliant mir- ror. To insure accuracy, the experiments should be per- formed, by daylight.
CHLOROrOKM.
Formula CHCl,.
Process. — Should the necessary appliances be at hand, a small quantity of this liquid may easily be prepared by the oflJcial process. Onefluidouncc and a half of spirit and 24 of water are placed in a retort or flask of at least a quart capacity ; 8 oz. of chlorinated lime and 4 of slaked lime are added, the vessel connected with a condenser, and the mixture heated until distillation commences, the source of heat then being withdrawn. The condensed liquid should fall into a small flask containing water at the bot- tom of which about a drachm of chloroform will slowly collect.
Explanation of Process. — The hypochlorite of calcium (Ca2CI0) belieyed to be present in tlie chlorinated lime (see remarks in con- nection with hypochlorona acid) readily yields up oxygen and chlo- rine to organic substances, the calcinm being liberated as hydrate, 4 (Ca20l0)+4Hi,O=4(Oa2HO)-i-2Oj+4Ol,. The alcohol used in making chloroform is thus reduced first to aldehjd : — 2C,H,0 + 0, = 2C,H,0 + 2H,0
Alcohol. Oxy^Q, Aldehyd. Waler,
The action of chlorine on aldehyd then probably gives chloral (cfttor-aMehyd) ■.—
03,0 -f 3C1, = C,HCLO + 3H01
Alaebrd. ChlotlDB. OhlorBl. Hydrotlil. acid.
The hydroolilorie acid being at once neutralized by some of the liberated hydrate of calcium to form chloride of calcium and water,
id .y Google
360 ALCOHOL AND ALLIED BODIES.
more freed hydrate of calcium and chloral give formate of calcium and chloroform.
2O.,H0LO + Oa2HO = Ca2CH0, + 2CHC1„
Chloral. Hydrale of ForiuHle of CUlotoforin.
Or, oeglecting the probable steps in the process, and regarding only the materials and the products, 4 molecules of alcohol and 8 of hypochlorite of calcium give 2 of chloroform, 3 of formate of cal- cium, 5 of chloride of calcium, and 8 of water, thus:—
40 JI.0 + SCaOLO, = 2CHOI3 4- 3(Oa2CHO j + 5CaCl, + IH^ Alcohol. HypouhlorUe Clloro/oini. Poriaale ol Chloriae vf Walar.
The hydrate of calcium placed in the generating-vessels is not ea- Benti^, but is useful in preventing secondary decompositions, the hydrate of calcium obtainable from the reaction being insufficient for this purpose.
(?o«sft"(M<«on.— Chloroform is sometimes considered to be the chlo- ride of a trivalent radical methenyl (OH), the first member of a series C„H„_,, Glycerine is the hydrate of another member—ffly- ceryl or propenyl, CjHj {p. 364).
Uhloroform may also be regarded aa the chloride of dichlor-metlijl ; it may be formed from inethylic compounds, thus : — 2CH,0 + 2(0aOl,,Ca01,O-) — 2CHCL + CaClsBCaO + 3H,0
Mothylic ChloriBaleil Chloroform. Osyclilorlde of Wiler,
BlfOhoL lime. calcium.
Chlorine converts it into tetrachloride of carbon, completing a series of STthstituiton produeia of chloride of methyl.
c|hIci cJhIcI C I Oil CI cjciloiorCOl,
Chloride of Chloiddeof Chloride of Chloride of Tetrachloride
melLyl. mono-chloc- di-chlor- Iri-ohlor- or of
jnelliyl. m^thyf. methyl, carhou.
The chloride of inoni>ch!or-methyl, nnder the name of dichloride of methylene, has been nsed as an anaesthetic.
Chloroform is purified by shaking it with wat«r and then with sul- phuric acid, which chars and removes hydrocarbons, but does not affect chloroform. It is freed from any trace of acid by agitation with lime, and from moisture by solid chloride of calcium.
Properties. — The sp. gr. of purified chloroform is 1.49 (1.49 to 1.494 U, S. P.). It readily and entirely volatilizes with character- istic odor at common temperatnres. It nas a sweetish tast«, is lim- pid, colorlffls, soluble in alcohol and ether, and slightly in water, but bums with a sluggish green smoky flame.
Cbloral.
Process. — Pasa a rapid stream of drj chlorine into pure
absolute alcohol so long as absorption occurs. During the
first hour or two the alcohol must be kept cool, afterwards
id .y Google
AMY1.1C ALCOHOL, 361
gradually warmed till ultimately the boiling point is reached. Tliepreparationof acoiieiderftble quantity occupies several days. The crude product is mixed with three times its volume of oil of vitriol and distilled, again mixed with a similar quantity of oil of vitriol and again distilled, and finally rectified from quicklime.
Properties. — The formula of cliloi-al is C^HCIjO. It is a colorless liquid of oily consistence. 8p. gr. 1.502. Boilmg point 201.2. Its vapor lias a penetrating smell and is somewhat irritating to the eves. Mixed with water heat is disengaged and solid, white, cryatalliKable, Iwdrovs chloral results. The latter fuses at 110.8 and boils at 29.HO R, subliming as a white crystalline powder- Both chloral and hy- drous chloral are soluble in water, alcohol, ether, and oils. The aqueous solution should be neutral and give no reaction with nitrate of silver. Hydrous chloral is said somtimes to undergo a sponta- neous change into an opaque white isomeric modification, insoluble in water, alcohol, or ether, but convertible by prolonged contact with water or by distillation into the ordinan" condition. By action of weak alkalies chloral yields formiat« of the alkali metal and chloro-
CsHOIjO + KHO = KCHO, + OHCl, Chloral, or rather strong aqueoas solution of hydrous chloral (3 in 4) injected beneath the skin yields nascent chloroform bv action of the alkali of the blood, and produces narcotic effects. (Liebrcich. Personne.) Chloroform itself admits of similar hypodermic use {Eich- ardson). If administered by the stomach thirty to eighty grains of solid hydrous chloral are required. The final product of the reac- tion of chloroform and blood are chloride and formiate of sodium. A spirituous solution of potash effects the same transformation. CHClj + 4NaH0 = NaOHO, + 3Na01 + 2H5O
AUYLIC ALCOHOL.
Amylio Alcouoi. (Alcohol Amylimm, B. P. and U". 8. P.) [G^B.^^ HO, or AvHO) is a constant accompaniment of ethylic or common alcohol ((J!,Hj,HO, or BtHO) when the latter is prepared from sugar which has been derived fi-om starch ; hence the name, from mtiyheni starch. The sugar of potato-starch yields a considerable quantity ; hence the alcohol is often called 'potaio-oil. It is also termed /ousel- oil, or fusel-oil (from ^ia, phtic, to produce), in allusion to the cir- cumstance that the supposed oil is not simply educed from a sub- stance already containing it, as is usually the case with oils, but is actually produced 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 a true spirit, homo- logous with spirit of wine. See also Vaibkiasic Arai).
Amylic alcohol is ''a colorless liquid with a penetrating and op- pressive odor, and a burning taste. When pure its specific graviiy
id, Google
3G2 ALCOItOL A«D ALLIED BODIES.
is 0.818 ; boiling-point 2790. Sparingly soluble in ■water, but soluble in all pTOportions in alcoiol, ether, and essential oils. Exposed tc the air in contact with platinum-black, it is slowly oxidized, yielding valerianic acid." Two allotropic varieties of amylic alcohol exist, one dextro-rotating a polarizea ray.
Acetate op Amyl (C^HjjCjHgO,, or AyA). To a small quantity of amylic alcohol in a test-tube add some acetate of potassium and a little sulphuric acid, and warm the mixture ; the vapor of acetate of amyl is evolved, recog- nized by its odor, which is that of the jargonelle pear. If a condenaing-tube be attached, the essence may be distilled over, washed by agitation with water to free it from alco- hol, and separated by a pipette.
K,A -+- AyHO + H^SO, = AyA + KH80, + H,0
Fruit-Emences.
Acetate of amyl, prepared with the proper equivalent proportions of constitnents as indicated by the above equation, is largely manu- factured for use as a flavoring agent by confeetioners. Valerianate of amyl (CjHjjCjHjOj) ia similarly used under the name of apple-oil. Bntyrate of ethyl (CIHjOjHjO,) closeiy resembles tie odor and flavor of the pine-apple ; tenanthylate of ethyl {OjHjOjHi,Oj) re- calls green-gage ; pelargonate of ethyl f OjHjCjHuOj) qnmce ; Bnbe- rate of ethyl (EtjCjHijO,) mulberry; sebacateof ethyl (EtjO,^„0,) melon. Hydride of sahcyl (CiHjOjH), or salicyloua acid, is the essential oil of meadow-sweet {Spiraea xditiaria), and may be pre-
fiared artificially bv the oxidation of salicin {^vide p. 345). Salioj- ate of methyl (OHsOjH.O,), or gaultheric a.ciA {Oleum, gav,lt'heri<e, "U.S. P.), is the essential oil of winter-green [Gaultheria promtm- hens), and may also be prepared artificially from salicin. By mix- ing liieee ethereal salts with each other and with essential oils in various proportions, the odor and flavor of nearly evcKy fmit maybe fairly imitated.
QL■ESTIO^fS AND EXERCISES,
757. Name the source of methylic alcohol.
758. What is "methylated spirit"?
759. Describe the method by which methylated spirit is detected in a tincture.
760. In what relation does formic acid stand to methylic alcohol?
761. How would you proceed to ascertain whether or not a speci- men of sweet spirit of nitre had been made from methylated spirit?
TG2. Give details of the production of chloroform from alcohol, tracing the various steps by equations.
id .y Google
PIIENYLTC ALCOHOL OR OARBOLIO ACID. 3fi3
763. Is chloroform an ethylic compound ? What is its probable conatitntion 1
764 How is chloroform purified?
765. State the character of pure chloroform.
766. Whence is amylic alcohol obtained ?
767. Has valeriaoic acid any chemical relation to amylic alcohol?
768. Mention the systematic names of several artificial fruit-
SAITS AMD DERIVATIVES OF RADICALS OF OTHER SERIES THAN THE C.H^i.
What has been stated regarding radicals having the general for- mula 0„H~4^ and their salts, may ba applied*to the radicals of other series. The series 0„H,,_, incindes vhenyl (CbH,), the hydride of which (OsHjH, or PhH) is common hmzol (B.P.), a colorless volatile lii^uid obtained from coal-tar. Benzol is a powerful solvent of grease, and under the name of Benzine Collas was introduced by M. Oollafi, in 1848, for cleansing stuffs. By the action of strong nitric acid, benzol yields mtrobemol (CjHjfNOj)), a liquid termed, from its odor, artifictal oil of bitter almonds, or essence ofmirbane. The odor of this essence, however, is not exactly that of essential oil of almonds, and its composition is very diiferent ; so that it is not truly an artificial volatile oil, the natural oil (OjHsOH) being a hydride of the negative radical benzoyl, a radical derived from Uie next higher homologne of phenyl by displacement of hydrogen by oxygen. The hydrate of phenyl (O5H5HO), or phenie alcohol, or phenol, is thephemc acid or carbolic acid of commerce {Acidam Carbolicum, S. P.), a colorless crystalline substance, obtained from coal-tar oil by fractional distillation and subsequent purification. At temperatures above 95'^ F. it is an oily liquid. It is only slightly soluble in water, but readily dissolved isy alcohol, ether, and glyce- rine (Glycerinum Addi Oarbolici, B. P.). In odor, taste, and solubility (and in appearance when liquefied by heat or by the addi- tion of 5 per cent of water) it resembles creasote (CpH,|,Oj), a wood- tar product for which carbolic acid is often suMtituted. Certain coloring-matters may be obtained by the osidatiou of carbolic acid i ammonia mixed with it, and then a small quantity of solution of a hypochlorite gives a blue liquid; a similar effect is produced on dip- ping a chi]) of deal into carbolic acid (or into crei^ote), then into hydrochloric acid, and afterwards exposing it to the air. By the following teats carbolic acid may be distinguished from creasote. The former boils only at 370^, while the latter readily dries up at 212°. Carbolic acid does not afifect a ray of polarized light ; crea- sote twists it to the right. Carbolic acid is either solid or may be solidified by cooling; creasote is not solidified by the cold produced by a mixture of hydrochloric acid and sulphate of sodium. Creasote from coal (impure or crude carbolic acid) gives a jelly when shaken with collodion ; creasote itom wood { Greasoturn, B. P, and U, S. P.)
id .y Google
364 ALCOHOt AND ALLIED BODIES.
m iinafFccted by collodion [Ruat). Coal-creasote is soluble in solution of potash, wood-oreasot* insoluble. The coal product is soluble in a large volume of wat«r, and a neutral solution of ferric chloride strikes a blue color with the liquid : wood-cveasote is less soluble (Aqua Greasoti, U. 8. P. is said to contain 1 in 129) and not altered by ferric chloride. An alcoholic solution of the coal-oil is colored brown by ferric chloride, a similar solution of true creasote green. Carbolic acid is a powerful antis^tic {&vti, anti, against, ana a^itw, sepo, to putrely). In large doses it is poisonous, the best antidote being olive oil and castor oil, freely administered. Both carbolic acid and benzol are secondary products, obtained in the manufacture of coal- gas ; hence, indeed the word phenic and thence phenyl (from fot'wi, phaiTUi, I light, in allusion to the use of coal-gas}. Aniline, or phenylamine, is a product of the action of nascent hydrogen on nitrobenzol,
O.H-NO, + 3H, = n] "n+2H,0, '•' ' I H
NItTolisnzol. Hyd rosea.
the substance whence, by oxidation, &e., aniline-red (magenta), -orange, -yellow, -green, -blue, -violet (mauve), and -black are pro- duced. Tri-nitro-carbolio acid (OsHj(NO,)jO) is the yellow dye known as picric acid ; most of the picrates are explosive by percus- sion. In the series 0„H,„_i' we have the anivalent radical allyl (0,Hj), wh(«e sulphide ({G^TiL)^) ia essential oil of garlic (Allium, U. S. P.) and sulphocjanate (C,H,0y8) the essential oil of mustard. Mustard (Sinapis, B. P. and U. 8. P.) is a powdered mistnre of black and white muslard-seeda. The black contains a ferment resembling the emiilsin of almonds (p. 341) and myronate of potas- sium. The latter is the body which, under the influence of the former, yields the oil. E:,C^H„N,8.0,, = 2(KHS0,) + 2O3H-CNS + 2C,H,i,0, + Jlfi
Jrfyronafeof Acid sulphLto Oil of OlucoBe. Walec.
Ailyl compounds are also met with in several other liliaceous and cruciferous plants. In the C,M_^ series occurs ethylene or olefiant gas (OjH,), the chief illuminating constituent of coal-gas (readily made on heating alcohol with twice its volume of strong sulphuric acid), a bivalent radical, the alcohol of which is glycol (CjH,2H0). Etherol, or Ethereal Oil {Oleum Etherev/m, U. S. P.), or light oil of wine (OijHj,?) a hydrocarbon polymeric with olefiant gas, is one of the prodncts of the action of eieess of sulphuric acid on alcohol: its sp. gr, is 0.917. In the GJi^,^,'" the trivalent hypothetical rad- ical glyceryl (C,,IIj) is found, the hydrate of which (CjHs3H0) is glyeerme. The homologues of glycol are termed glycols, the homo- logues of glycerine glycerines.
Glycerine.
Glycerine, or Glyceric Alcohol (0,H;3H0).— Glycerine is the hydrate of glyceryl, glycyl, or propenyl— the basylous radical of
id, Google
most oils and fats. These latter are mainly oleates, palmitates, and stearates of g-1 jceryl ; and when heated with metallic nydrates (even with water — hydrate of hj-drogen, HHO — at a temp, of 500^ or 60(P P.) yield oleate, palmitate or atearate of the metal, and hydrate of glyceryl or glycerine. Hence glycerine is a by-prodoot iu the manufacture of soap, hard candles, and lead-plaster (vide pp. 170 and 311).
Properties. — Glycerine is viscid mhen pure, specific gravity 1.28 (not helow 1.2S, B. F.), has a sweet tast*, is solnble in water or alcohol in all proporfiona. It has remarkable powers as a solvent, ii
Test. — Heat one or two drops of glycerine in a test-tube, alone or with strong sulphuric acid, acid sulphate of potas- sium, or other salt powerfully absorbent of water ; vapors of acrolein (from acer, sharp, and oleum, oil) are evolved, recognized by their powerftilly irritating effects on the eyes and respiratory passages. If the glycerine be in solution in water, it must be evaporated as low as possible before applying this teat. Besides glycerine itself (Olycerinum, B. P., Olycerina, U, S. P.)) there are several official prepa- rations of glycerine — solutions of carbolic, gallic, and tan- nic acids and borax in glycerine, and a sort of mucilage of starch in glycerine (Glj/cerinum Acidi GarboUot, Oly- cerinum Aeidi Oallici, Glyoerinum Acidi Tannici, Olyce- rinum. Boracis, and Olycerinum, Amyli).
QUESTIONS AND EXBEOISES.
benaol, essential oil of mnstard, glycerine, and glycol.
770. State the difference iu composition of natural and artificial oil of bitter almonds.
771. How is the so-called artificial oil of bitter almonds prepared ?
772. What are the nses, composition, source, and properties of Carbolic Acid ?
773. State the characters by which carbolic acid is distinguished from Oreasote.
774. Draw out an equation explanatory of the production of aniline.
IIS. Mention the chief properties of Glycerine.
776. What is the speeinc gravity of glycerine ?
777. By what test is glycerine recognized ?
778. Enumerate some official preparatioaa in which glycerine is employed as a solvent.
31*
id .y Google
6blj AI.IiTJMENOID SUBSTANCES.
ALBTTMENOID SUBSTANCES.
Albumen. — Agitate, thoroughly, white of egg (Albumen Ovi, B, P.) with water, and strain or pour ofi' the liquid from the floeculent membrauous insoluble matter. One white to 4 ozs, of water forms the "Solution of Albumen," B. P.
Test. — Heat a portion of this solution of albumen to the boiling-point; the albumen becomes insoluble, separating in clots or eoagula of characteristic appearance.
Other Reactions. — Add to small quantities of aqueous solution of albumen solutions of corrosive sublimate, nitrate of silver, sulphate of copper, acetate of lead, alum, perchloride of tin ; the various salts not only coagulate but form insoluble compounds with albumen. Hence the value of an egg as a temporary antidote in cases of poi- soning by many metallic salts, its administration retarding the absorption of the poison until the stomach-pump or other measures can be applied. Sulphuric, nitric, and hydrochloric acids precipitate albumen ; the coagulum is slowly redissolved by aid of heat, a brown, yellow, or pur- plish-red color being produced. Neither acetic, tartaric, nor organic acids, generally,exceptgallo-tannic, coagulate albumen. Alkalies prevent the precipitation of albumen.
Yolh or Yelk of Egg (Ovi ViteUm, B. P.) contains only 3 per cent, of albumen— the white 12^, The yolk also contains only 30 per cent, of yellow fat and 14 of casein. The whole egg (Os/Mm, U.S. P.) is also official.
Albumen is met with in large quantities in the serura of blood, in smaller quantity in chyle and lymph, and in the brain, kidneys, liver, muscles, and pancreas. It is not a normal constituent of saliva, gastric juice, bile, or mncns, but occurs in those secretions during mflammation. It is found in tie urine and feces only under certain diseased states of the system.
""' le of the coagulation of albumen by heat has not yet been
Albumen has never been obtained sufficiently pure to admit of its composition being expressed by a trustworthy formula; Gerhaidt regarded it as a sodium compound (HNaC^HiioNijSOjj.KjO).
Fibrin, Casein, Legumin.
Fibrin is the chief constituent of the muscular tissue of animals. It occurs m Bolation in the blood ; and its spontaneous solidification or coagulation is the causeof the ctoHsmj of blood shortly after being drawn from the body— a phenomenon which cannot at present be
id .y Google
ffi
e;ipliiiiiert satisfactorily. Fibrin may be obtained by whipping: fresh blood with a bundle of twigs, separating the adherent fibres, and wasiiing in water till colorless.
Average CompoBition of Blood (in 1000 parts). {Compiled by Kirtcs.)
Water 784
Albumen 70
Fibrin 2.2
Bed Corpuscles: Globulin 123,o
Hcematin 7.5
Oholesterin O.OS "
m Cerebrin O.-IO
^^ Serolin I ^^
[g ^ ' Oleic and margarie acids
a Volatile and odorous fatty acid . . . Fat containing Phosphorus
Chloride of sodium 3.fi
o Chloride of pota^ium .36
Phosphate of sodiam (NajPO,) .2
Carbonate of sodium .84
^ Sulphate of sodium .28
'"' Phosphates of cakinm and magnesium .... .25
[Oxide and phosphate of iron .50
Estractive matters, biliary-coloriug-niatter, gases, and
accidental sialjstances 5.47
1000. Percentage proportion of the c7tie/ constituents of lilood.
Water 78.4
Red corpuscles 13.1
Albumen of serum 7.0.
Inorganic salts 603
Extractive, fatty, and other matters . . . .077 Fibrin 22
100.
Casein, occurs in Cow's Milk (Lac, B. P.) to the extent of 3 per cent., dissolved by a trace of alkaline salt. Its solution does not spontaneously coagulate like that of fibrin, nor by heat like albumen ; but acids cause its precipitation from milk in the form of a card (cheese) containing the fat (butter)-globu!es previously suspended in the milk, a clear yellow liquid (or whey) remaining. Curds and whey are also produced on adding to milk a piece, or an infusion, of rennet, the salted and dried inner membrane of the fourth stomach of the caif. The exact action of rennet is not known.
id .y Google
ALBUM ENOTD I
|
Average composit |
on. of 1000 pa |
ts of Milk. |
|||||
|
Speeiflo eravity. |
Water. |
Solid oonsti- |
Ca.in traettTe |
Sngar. , Butter |
Salts. |
||
|
Woman .... |
1.033 |
889 |
111 136 |
40 55 |
44 38 |
27 36 |
2 |
Specific g^ravity alone, as taken by the form of hydrometer termed ft lactoiiieler, 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 inflwnce in opposite directions. Good cow's milk affords from 11 to 13 per cent, by volume of cream, and 3 to 3^ per cent of butter. The water of raUk seidom or never varies more than from 86J to Sli per cent, and the solid constituents from 13^ to 12^. Town milk is commonly 3 and sometimes 2 parts milk and 1 part wafer. Under the microscope milk is seen to conswt of minute cor- puscles floating in & transparent medium. These corpuscles consist of fatty matter (butter) contained in a filmy albumenoid envelope.
Legumin or vegetable casein is found in most leguminons seeds, such as sweet and bitter almonds. Feas contain about 25 per cent, of legumin.
Vegetable albumen is contained in many plant-juices, and is deposited in flooculi on heatiM such liqaids. 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 {vide p. 368),
Albttmenoid substances are nearly identical in percentage compo- sition. Albumen (and fibrin) contains 63.5of carbon, 1 of hydrogen, 15.5 of nitrogen, 22 of oxygen, 1.6 of sulphur, and .4 of phosphorus. Casein contains no phosphorus. These three bodies are often termed the plastic elements of nutrition, under the assumption that animals directly assimilate them in forming muscles, nerves, and other tissues, — starch, sugar, and similar matter forming the respiratory materials of food, because more immediately concerned in keeping np the temperature of the body by the combustion going on between them, and their products, and the osvgen of the air in the blood.
Musk (Moschus, B. P. and U, S. P.), " the inspissated and dried secretion from the preputial follicles of Mtisclms moschiferus" (the Musk-Deer), is a mixture of albumenoid, fatty, and other animal matters with a volatile odorous substance of wnkaown composition.
GELATIGEN0U8 SUBSTANCES.
This gronp of nitrogenous bodies diiFcrs from true albumenoid in containing less carbon and sulphur and more nitrogen. They are contained in certain animal tisanes, and on boiling with water yield a solution which has the remarkable property of solidifying to a
id .y Google
jelly oil cooling. The tendons, ligaments, bones, skin, and serous membi-anes aiford gdatirte proper; the cartilages give chondrine, whict differs from gelatine in composition and in being precipitated by vegetable acids, alum, and the acetates of lead. The purest variety of gelatine is isinglass, B, P. {Iclki/ocoUa, U. 8. P.), "the swimming-bladder or soand of Tarions species of Acipenser, Linn,,
Srepared and cut in fine shreds." Small quantities are more easily isintegrated by a file than a knife. Fifty grains dissolved in 5 ounces of distilled water forms the official "Solution of Gelatine," B. P. Glue is an impure variety of gelatine, made from the trimmings of hides; size is glne of inferior tenacity, prepared from the paring of parchment ana thin skins. "Among the varieties of gelatine derived from different tissues and from the same Bonrcea at different ages, much diversity exists as to the flrmne^ and other characters of the solid formed on the cooling of the solutions. The differences between isinglass, siae, and gloe, in these respects, are fitmiliarly known, and afford good examples of the varieti^ called weak and strong, or low and high, gelatines. The differences are sometimes ascribed to the quantities of water combined in each case with the pure or anhy- drous gelatine, part of which water seems to be chemically combined with the gelatine; 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 snch a change is effected in the gradual process of nutrition of the tissues ; for, as a general rule, the tisanes of an old animal yield a much firmer or stronger jelly than the corresponding parts of a young animalof the same species." (Kirke's Physiology.) Gelatine appears to anite chemicaify with a portion of the water in which it is soaked when used for culinary and mauufactaring purposes, for a solution of glue in hot anhydrous glycerine does not yield an ordinary jelly on cooling.
TEPSINE.
e (from ttirtta, pepto, to digest) is a nitrogenous substance existing in the gastric juice, and as a viscid matter in the peptic glands and on the walls of the stomachs of animals. The mucous membrane of the stomach (of the hog, sheep, or calf, killed fasting) is scraped, and macerated in cold water for twelve hours; the pep- sine in the strained liijuid is then precipitated by acetate of lead, the deposit washed once or twice by decantation, sulphuretted hy- drogen passed through the mixture of the deposit with a litde water to remove the whole of the lead, and the filtered liquid evapo- rated to dimness at a temperature not exceeding lOS*^ P. Pepsine is a powerful promoter of diction ; its solution is hence frequently termed artificial gastric juice. As met with in pharmacy its strength varies greatly. It is often prepared by simply mixing with starch the thick liquid obtained on macerating the scraped stomach with water, and evaporating to dryness. (Tide Pharmaceutical Journal, 18G5-66, p. 112).
id .y Google
ATTY BODIES
QUESTIONS AND EXERCISES.
779. In what form is albumen familiar ?
780. Name the chief test for albumen
781. Whyistheadministrationofalbmnen useful in cases of poison- ing ?
782. Mention the points of difference between yolk and white of
783. From what eonrces other tnan egg may albumen be obtained ?
784. In what respects does fibrin differ from albumen ?
785. Bnamerate the chief constituents of blood.
786. How may fibrin be obtained from blood ?
787. State the difference between casein, fibrin, and albumen.
788. What are the relations of cream, butter, curds and whey, and cheese, to milk ?
789. Describe the microscopic appearances of blood and of milk.
790. How much cream should be obtained from good milk ?
791. What is the percentage of water in genuine milk ?
792. Name sources of vegetable casein and vegetable albumen.
793. Give the percentage of nitrogen in aibumeooid si ' '
794. Describe the chemical nature of mnsk.
795. In what lie the peculiarities of gelatine ?
796. To what extent do isinglass, glue, and size differ !
797. Whence is pepsine obtained ?
798. How is pcpsino prepared !
FATTY BODIES.
General relations. — Oils and fats are, apparently, almost as sim- ple in constitution as ordinary inorganic salts. Just as acetate of potassium (KCgHjO,) is regarded as a compound of potassium (K) with the characteristic elements of al! acetates (OJljO,), so soft soap is considered to be a compound of potassium (K) witn the ele- ments characteristic of all oleates (CyH„Oi,), and bence is chemically termed oieate of potassium {KOmHjjOj). Olive oil, from which soap is commonly prepared, is niaifly oieate. of the trivalent radical glyceryl (CjHJ, the formula of pure fluid oil being C.HsSCisHjjO,, ■ and its name oieine. The formation of a soap, therefore, on brmg- ing together oil and a moist oside or hydrate, is a simple case of double decomposition, as seen already in connection with lead plaster (p. 170), or in the following equation relating to the formation of common hard soap ; —
SNaHO + 0-H,30„H^30, = 3NaC,8H„03 + C,H^3H0
Hydrate of sodrnm Oieate of glyceryl Oieate of BOdlom Hydrate of glyceryl (caustlD soda). (vegetatle oil). (lur^ sosp). (glycerTne).
Berthelot has sncteeded in preparing oil artificially from oleic acid and glycerine ; and it is said to be identical with the pure of olcine of
id .y Google
SOAPS. 311
olive and of other fixed oils. Hard fats chiefly consist of sfearine — that is, of trjstearate of glyceryl (OjHsBO^HasO,). Mr. Wilaoii, of Price's Candle Company, obtains stearic and oleic acids and glycerine by simply passing steam, heated to 500° or 600° F., througn melted fat. Both the glycerine and fat afiids distil over in the cnrrent of steam, the glyeerioe dissolving in the condensed water, the fat-acids floating on the aqueous liquid.
Soaps. — Olive oil boiled with solution of potash yields potassium soap, or soft soap (Sapo Mollis, B. P.) ; with soda, sodium soap, or hard soap {Sapo Durus, B. P. and U. 8. P.); mixed with ammonia, an ammonium soap {Lini- mentum Ammonim, B. P. and TJ. S, P.) ; and with lime- water, calcium soap {Linimentum Galcis, B, P. and — flax- seed oil— U. S, P.), — all oleates, chiefly of the respective basylous ra<.lieals. The alkali soaps are soluble in alcohol, the others insoluble. The ofilcia! characters of Hard Soap are : "■ grayish- white, dry, inodorous ; liorny and pulver- izable when kept in dry warm air ; easily moulded when heated; soluble in rectified spirit; not imparting an oily stain to paper ; incinerated it yields an ash which does not deliquesce." And of Soft Soap ; " yellowish -green, ino- dorous, of a gelatinous consistence : soluble in rectified spirit; not imparting an oily stain to paper: incinerated it yields an ash which is very deliquescent."
Site, the gall of the ox (Bos tauvis, liinn.J, freed from roncus by agitating with twice its hulk of rectifiad spirit (in which mucus is insoluble), filtering, and evaporatii^, yields the official Purified Ox- Bile (FdBovinum Pmijicatum,, B. P.) : the latter has a resinous appearance, but is chiefly composed of two crystalline substances having the constitution of a soap ; the one is glycockolate, or simply cholate, of sodium (NaC«HjjNO,}, the other is termed tauro- ckolate of sodivM (NaC5,HjjN0,S), Both tanrocholates aad gly- cocholates are conjugated bodies readily yielding, the former cho- lalic acid (HjO„Hs,Oj) and taurine (0 Jl,NO,S), the latter eholalic acid and glycocine or glyeocoll (O.HsNOs), a body having interest- ing physiological relations, inasmuch as it is obtainable from gelatine (hence the name gljcocoll, from ■fl.vxii;, glutMS, sweet, and x6*.tjt, koUa, glue) and hippuric aeid.
Solid Pats. — 1. Lard [Adeps Prceparatus, B. P. and tJ. S. P.) is the purified internal fat of the abdomen of the hog— the perfectly fresh omentum or flare, washed, melted, strained, and dried. 2. B&nxoat6d Lard {Ad^s Beneoat'us, B. P.) is prepared lard heated over a water-bath with benaoin (10 grains per ounce), which commu- nicates an agreeable odor and prevents or retarite rancidity. Purified lard is a mixture of oleine and stearine ; niarga^ne, the margarate of glyceryl, was formerly supposed to be a constituent of lard and other soft fats, bnt is now regarded as a mere mixture of palmitine (the chief fat of palm oil) and stearine. 3. Yellow Wax { Cera Fiava,
id .y Google
372 PATTY B0IUE8.
B. P. and U. S. P.), the prepared honeycomb of the Hive-Bee, and the same bleached by exposure to sunlight 4. White Wax (Cera Alha, B. F. and U. 8. P.), according to Brodie, is chiefly a mixture of Cerottc Acid (BC^JiiiOX Pcdmitate of Meltssyl [C^H^C.^aiO,), and about 5 per cent, of Ceroleine, the body to which the color, odor, and tenacity of wax are due, 5, Spermaceti ( Cetaceum, B. P. and U. 8.F.)isthspali>iitateofceitil{C,fi,fi,,'H.^iO„),oTceltne; when sapo- nified it yields not glycerine, the hydrate or glyceryl (OjHjBHO), bat ethai, the hydrate of cetyl (CieHj^JIO) ; it is the solid crystalline fat accompanying sperm oil in the nead of the spermaceti-whale. 6. Suet, the internal rat of the abdomen of thesheep, purified by melting and straiDing, forma the official /Vepared Sviet {Sevum Prc^aratwm, B. P. and U. S. P.); it is almost exclusively composed of stearin (CiHsSCuiHssO,). 7. Expressed oil oi nutmeg [Oleum MyristiecB Expressmnla. P.) is a mixture of a little volatile oil with much yel- low and white fat, the latteramyristate of glyceryl (C„H530,,H_Oj). 8. Oil of theohroma, OY OacaoJiviter {OUum Tlieobromce, B. P. and U. S. P.), is a solid product of the ground seeds or cocoa nibs of the Tkeohroma cacao, which also furniSi cocoa, and cAocoioie. 9. Goeow- nut oil, a soft fat largely contained in the edible portion of the nut of Cocos nucifera, or common cocoa-nut of the shops, a body con- taining glyceryl united with no less than six different univalent acid- nlone radicals, namely, the caproic (C,H„0,), caprylic {OsH.sO,), rutic (CjaHniOj), lanric (0,iH,sO,), myristic (C„H„05),and paSiitic (C,fHjiO,j) — radicals which, like some from common resin, when united with sodium, form a soap differing fi-om ordinary hard soap (oleate of sodium) by being tolerahly soluble in a solution of chloride of sodium ; hence the use of cocoa-nut oil and resin in making marine soap, a soap which, for the reason just indicated, readily yields a lather in sea-water.
Fixed Oils. — Fixed and Volatile oils are natnrally distinguished by flieir behavior when heated ; they also differ in chemical constitu- tion, ft fixed oil being, apparently, a combination of a bnsylous with an acidulous radical, while a volatile oil is commonly a neutral hy- drocarbon.
Drying and Non-diytng Oils. — Among fixed oils, most of which are oleate with a little palmitate and stearate of glyceryl, a few, such as, 1, linseed (Oleum Lint, B. P. and U. S. P., contained in Lini Semina, B. P., Linum, U, S. P., or Flasseed, the ground residue of which, after removal of the oil, is linseed meal, Liini Farina, U. 8. P.), and, 2, codiivm {Olmim Morrhw<x, B. P. und U. S. P.), and, to some extent, castor and croton, are known as drying oils, from the readiness with which they absorb oxygen and become hardened to a resin. Among the non-drying oils are : 3, almond oil, indifferently yielded by the bitter (Amygdala ArMira, B. P. and U. 8. P.) or sweet seed (Amygdoia Dtdds, B. P. and TJ. 8. P.) ; 4, eroton oil (Oleum Crotoma, B. P., Oleum Tiglii, IT. 8, P.), which seems to contain (yrotonate of glyceryl (G^^ZG^fi^ ; 5, olive oil (Oleum Olivm, B. P. and U. 8. P.), already noticed; 6, castor oil (Oleum Bicini, B. P.andtF. S. P.), a ricinoleate of glyceryl (O.HsSO^ELjO,) or ricinoleine, a slightly oxidized oleine, soluble, unlike moat fixed oils, in alcohol ; ^, oil of male fern (Filix Mas, B. P. and U. S. P.),
id .y Google
FIXED OILS, 3T3
a vermifuge obtained by exliauating the vhizome with ether and re- moving the ether by evaporation— a dark-colored oi! containing a little volatile oil and resin, ajid officially termed an extract (Sic- fracfum FUiois Ldqmdimi, B. P.) ; 8, fixed oil of m/astard, a bland, iuodorouB yellow or amber oil, yieldiug by saponification, and action of sulphuric add, glycerine, oleic acid and erucic acid, HC^Hffi, (Darby) ; 9, Lycoyodiwm OH from the sporulea of Clnb-mosa ; 10, Neae&foot Oil iOlemn Bubulvm, U. 8. P.)-
Their phyaical qualities and the formulas of their acidulous radi- cals show that the &tty bodies are closely related, and indicate that the natnral procflsses by whicli they are formed are probably as closely related. The following Table, from Miller's "Elements of Chemis- try," well shows the homology of the fat-acids, and gives their names, formula, melting-points, boiling-points, and natural and arlificial
|
sour |
*s. |
||||||
|
■Ids |
Fomiilffi |
Mel 11 n |
polBl. |
BolUug |
polol. |
Whence obtained |
|
|
Mol8c. Vol, = a |
|||||||
|
"P. |
"C. |
"!'. |
°C. |
fEed ants; distillation of |
|||
|
HC H O2 |
21 |
221 |
105.3 |
oxalic acid; and oxida- tion of HDiylaoaovis and oilier organic bodies. |
|||
|
(Distillation of wood; |
|||||||
|
!!Cj Ha Oj |
63 |
17 |
243 |
117 |
J oxidation of alco- ( hoi, &c. |
i |
|
|
)iiic ... |
nc^ Hj 0, |
2M |
140 |
\ cerln, &o. I Butter ; fermenta- |
1 |
||
|
'" |
HC^ H, O2 |
below |
—20 |
314 |
167 |
J tionoflactioadd, { Valerian-root; osi- |
"i |
|
ani.... |
HC, Hj Oj |
" |
347 |
175 |
? dation of fousel ( oil. |
o§ |
|
|
HCeH|,0, |
392 |
200 |
Butter. |
g |
|||
|
thylio. |
HCj H|j |
298! |
148? |
( Castor oil by diatil- t lation, &o. |
1 |
||
|
lie |
HC, H.^O, |
59 |
15 |
457 |
23S |
Butter; coooa-nut oil. |
|
|
HC, H„Oj |
... |
500 |
260 |
( Leaves of tbe gera- |
fr. |
||
|
HC,„H„0, |
86 |
30 |
f Butter:' oil of rue bj"si- ( datiou. |
||||
|
, |
HCijHjjOj |
110 |
43 |
( Coooa-nut oil ; berries of the \ bay tree. ( Nutmeg-butter ; cocoa-nut \ oil, &c. |
|||
|
ie |
HC,,Hj,0, |
129 |
54 |
... |
|||
|
tio |
HCijHjiOj |
143.6 |
62 |
... |
i Palm oil; butter ; beeswax, \ ke. |
||
|
HC.sHjjOj |
169 |
70.5 |
Host solid animal fats. |
||||
|
idle!"' |
HC,„H3,0j |
167 |
75 |
Butter; oil of grouud-iint. |
|||
|
HC H>, |
174 |
79 |
lie^swas. |
||||
|
io |
BC„H,sOj |
193 |
89 |
Beeswax. |
id, Google
QUESTIONS AND EXEE0ISE8,
199. (live a sketch of the general ciemistrj of fixed oils, fats and Boaps.
800. What is the diffevence between Hard and Soft Soap ?
801. Which soaps are official ?
802. Name the source of lard, and state how " Prepared Lard" is obtained.
803. State the composition of Beeswax.
804. In what does Spermaceti differ from other solid fats ?
805. Mention the chief constituent of Suet.
806. Whence is Cacao-Butter obtained?
807. Why is marine soap so caDed, and from what fattj matter is it esclusively prepared ?
808. What do you understand by drying and non-drying oils?
809. In what respect does Castor Oil differ from other oils ?
810. How is oil of male fern (Ex. FUicis Idquidum) prepared?
811. Mention the sources ana formnlie of the following fat-acids : formic, acetic, propionic, butyric, Talerianic, caproic, cenanthylic, caprylic, pelargonic, and rutic.
Volatile Orr.s.^The Volatile or Essential Otis exist in various parts of plants probably as mere combinations of carbon and hydro- gen ; bnt such hydrocarbons are prone to change when in contact with oxygen or moisture ; hence these liquids as they occur in phar- macy are usually mixtures of liquid hydrocarbons or elceoptens with oxiized hydrocarbons, which are commonly solid or camphor-like bodies termed stearoptens. On cooling a volatOe oil, a stearopten (from ffTf'ap, dear, suet) often crystallizes out ; or on distilling an oil, it remains in the retort, being less volatile thau an eiseopten (from exatov, elaion, oil, and StttnuM, oplcmai, to see). Volatile oils should be preserved in well-o!osed bottles.
The process by which volatile oils are usually obtained from herbs, flowers, fruits, or seeds, may be imitated on the small scale bj' placing the material (bruised cloves or carawaj-s for instance) in a tubulated retort, adapting the retort to a Liebig's condenser, and passing steam, gene- rated in a Florence flask, through a glass tube to the bottom of the retort. The steam in its passage upward through the substance will carry the oil over the neck of the retort into the condenser, and thence, liquefied and cooled, into the receiving vessel, where the oil will be found floating on the water. It may be collected by run- ning off. the distillate through a glass funnel having a stopcock in the neck, or by letting the water from the con- denser drop into an old test-tube which has a small hole
id .y Google
VOLATILE OILS. 3T5
ill tlie bottom, ov any similar tulie placed in a larger ves- sel, the water and oil being subsequently run off separately from the tube as from a pipette. The water will in most eases be the ordinary official medicated water of the mate- rial operated on (Aqua Aurantii Floris, Anelhi, Carui, Cinnamomi, Fceniouli, Mentkee Piperitie, Menthse Viridis, Pimentee, Moste — from £osge Gentifolim Petala, B, P. and U. S, P. — Sambuci). Volatile oila, like fixed oils, stain paper, but the stain of the former ia not permanent like that of the latter. Oils of lemon and orange are sometimes obtained h^ mere pressure of the rind of the fruit.
A large number of volatile oils are employed in medicine, either in the pure state, in the form of satnrated aqueous solution (medicated waters), solution in spirit of wine, 1 in 5 {^Ementia Anisi and Essen- tia Mentha Piperitce, B. P.) and 1 iu 50 (S])ti-itiis CajupiUi, Juni- peri, LavandulcB, Meikthis piperita, MynsUcce, Rosmarint), or as leading constituents in various barks, roots, leaves, &c. The strength of SmWfits Anisi, U. 8. P. ; Sp. CinnamoTni, U. 8. P. ; Sp. Menthce hperitce, V. S. P. and Sp. Menth. Viridis, U. S. P., is 1 of oil to 15 or spirit of wine. Perfvmes ("scents" or "essences," incindiog " Lavender-Water" and " Ban de Colore") are for the most part eolations of Msential oils in spirit of wme, or spirituona infusions of materials containing essential oils. The following oils are, directly or indirectly, official in the British Pharmacopeia. 1. Volatile oO of Sifter Alvwnd (p. 3il}. 2. Oil of Bill {Oleum Anethi, B, P.), a pale yellow, pungent, acrid liquid distilled from dill-fniit 3. Oil of Aniseed {Oleum Anisi, B. P.), a colorless or pale yellow liquid, of sweetish warm flavor, distilled in Europe from the Anise-fruit {Pimpinella anisum), and iu China ii'om the fruit of Star-Anis {Imdum anieatum) ; it is a mixture of a hydrocarbon isomeric with oil of turpentine and a stearopten (C„,H,^0), which crystallizes out at low temperatures. 4 Oil of Cham.om.tle { Oleitm AnthemidiB, B. P.), a bluish or, when old, yellow oil, of character- istic odor and taste, distilled from chamomile-aowerfe {Anthemidis flores, B. P.) : the official variety (Antheiais nohilia] yields an oil composed of a hydrocarbon (0,„H,j) and an oxidiaed portion (OijHijO, or OgHjO) which, heated with potash, gives angdate of potassium {KOjH,O.J, whence is obtained angelic acirf {HOjH.O,} ; while the flowers of another variety {Matricaria Ohamomilla, U. S. P.) contain a stearopten (On,H|pO) having the composition of laurel- camphor. 5. Oil of Horseradtsh-root {Armoraeiee Raddx, B. P.) is, according to Hofmann, the sulphocyanate of butyl (0,HjCNS), p. 356 : it is the chief active ingredient of Spiritus Armoradce Compositus, B. P. 6. Oil of Sweet-Orange Peel {Aurantii DvXcis Gortex, U.S. P.) and Oil of Bitter-Orange rind {Aurantii Amari Cortex, B. P. and U. S. P.), the lavormg constituent of the official syrupof the j)eei(Syra)Ws.d)n'a)i(iV,B.P.), andtheoilsOf, 7, lemon {Oleum Limoms, B. P. and U.S. P.), from Lemon Peel (Limonis CoTtex,V.B.'F.)\ 8,lime; 9,bm-gamot{OleumBerganiii,U.3.P.)i
id .y Google
10, citron and a variety of citron termed cedra, resemble eaeh other in composition, coutaimng a hydi'ocarbon (CjjHj,) and a small qnan- titj of oxidized hydrocarbons {G^B.^^^ and OijH,oO.). 11. Oil of Neroli or Orange-Flower, the aqueous solution of which is official in the forms of water [Aqua Aurantii Floris, B. P. and U. S. P.) and ayrup (SyrupuB Aurantii Floris, B. P. and tJ. S. P.), contains a fragrant hydrocarbon (Ck^,,), colorless when fresh, bnt becoming red on expoBnre to light, ana an inodoroos oxidized hydrocarbon. 12. Oil of BuchiUeaves (^Buchu Folia, B. P. and tJ. S. P.) consists of a hydrocarbon holding in solution a crystalline stearopten. 13. Oil of Cardamoms, from the seeds of the capsules { Cardamonvum, B. P. and TJ. 8. P.), is chiefly a hydrocarbon (CioH^) isomeric with oil of turpentine. 14. OaotCajv^ut {Oleum, Ga]v,piUi,B.'P. andU.S.P.) is a mobile bluish liquid the composition of which (C,„H[gO) seems to be that of the common hydrocarbon associated with the elements of water. 15. Oil of Carawcsy-frnit (Oarum, U. S. P.) [Oletim Garui, B. P., Oleum Oari, XJ. 8. F.) is a miztnre of carvene (G,^„) and caruoi (O^HuO). 16. OH ot Cloves {Oleum Gari/ophylli,B.F. and U. S. P.) and of Pimmto ( Oleum Fimmtee, B. P. andtl. S. P.), both heavier than watfir, contain a liquid hydrocarbon (C,qH,,), eugenic acid (CujHuOj), a solid body, eugentn, isomeric wiUi eu- genic acid, anda second crystalline substance, caryophyllin{CiM.jfi), isomeric witii common camphor. VI. Oil of CascarsKa-bark (Casca- riWce OorteiB.B.P. andU.S.P.) has not beenfallyexamined. 18. Oil of Cinnamon-h&vk (Cinnamomi Cortex, B. P. and U, S. P.) and 19, of Cassiorbaik is mostly hydride of cinnamyl (OJH,OH). Boiled with nitric acid it furnishes hvdride of benzoyl (0,13^011) and ben- zoic acid (HC.H-Os), with chloride of lime yields benzoate of cal- cium (Oa20jH,0,), and with caustic potash gives cinnamate of potassium (K<Xh,Os). The specific gravity of oil of cinnamon ( Oleum Cinnamomi, B. P. and IF. 8. P!) varies from 1.025 to 1.050. 20. Oil of Oopaiva { Oleum Gopaibw, B. P. and U. S. P.) and, 21, of Gubebs ( Oleum Ciibebce, B. P. and U. J3, P.) are hydrocarbons having the formula OijH^ 22. Oiiol Coriander {GoriandrifruGtiis,~B.'P., Goriandram, U/S-V., Oleum Goriandri, B.PJ seems to have the composition of hydrous oil of turpentine (Cj„HijHjO). 23. Oil of Juniper ( Oleum Juniperi, B. P. and U. S. r.J, the active constituent of Juniper Tops and Berries {Juniperus, U. S. P.), is a hydrocarbon (OyH|j) which by contact with water yields a white crystalline hydrous compound (OjiJI,.HjO). 24. Oil of FenneLtruit {Oleum Funiculi, U. S. P.) {Fcemeuli Fructus, B. P. and U. S. P.) difTers in odor, but contains the same proximate constituents as oil of anise. 25. Oil of Lavmider {Oleum Lavanduice, B.P. and U.8.P.) con- tains a hydrocarbon which by oxidation yields common camphor. 25a. Oil or Butter of Orris {Iris Florentina) is a soft camphor (0„H„Oj), lighter than water. 26. Oil of Peppermint {Oleiim Menthce i*ipent<B, B. P. and TJ. S. P.) consists of a hydroearbon, menthene (OiaHuJ^differs from that of most volatOe oils, and hydrous menthene (CnjH.gHjO), a crystalline stearopten. 27. Oil of Spear- mint (Oleum Menthce Viridis, B. P. and U. S. P.) is expressed by theformnlaOi(|H„0. 28. Oil of Nutmeg {Oleum Myristicm,'B.y.
id .y Google
VOLATILE OILS. Stt
andU. 8. p.) and of the adllua of the nutmeg ov mace (Mam, U.S. P.) is composed of a hydrocarbon and the same more or less oxi- dized. 29. Oil or Otto or Attar of Oabbage-Rose petals (Boite Centifolim Petals, B. P. and U. S. P., Oleum Rosai, U. S. P.) gives the fragrance to Rose-water {Aqua Bosce, B. P.). It resembles most other volatile oils in being composed of a hydrocarbon and an oxi- dized portion, hut differs from all in this r^ipect, that the hydro- carbon ia solid and is destitnte of odor, while the oxygenated constitnent is liquid and the source of the perfume. According to Fliickiger the soiid hydrocarbon (ObHu) yields succinic acid as the chief product of its oxidation by nitric acid, and in other respects affords evitlence of belonging to the paraffin series of fets. 30. Oil of Roseraary4op8 ( Oleum Rosmanni, B. P. and U. S. P.) is a mix- ture of hydrocarbon, oxygenized oil, and stearopten in variable pro- portions. 31. Oil of Rue (Olewn RidiE, B. P.) contains a small cjuantity of hydrocarbon {0,„H„) with somerutic aldehjd (Cj„Ha,0), butaeeordingtoGrevilleWilliamsischieflyeiiodicaldehyd(Oi,H.,0), BomelaurioSdehyd (CijHj,0) also being present. 32. OiiofSavtn (OiemmSa&j'rate, B. P. and U. S. P.) is isomeric with oil of turpen- tine (Oi„Hi,). 33. Oil of Elde^--flov)era (Sambuci Flares, B. P. and U.S. P.) occurs in very small quantity; it has a bntyraceous con- sistenoe. 34. Oil of Sassafrae-voot (Oleum Sassafras, U. S. P.) specific gravity 1.094 (Sassafras Radix, B. P. and U. S. P.) yields Bafren (C|„H|,) and large quantities of a stearopten, sassafrol {U,oH„OJ. 35. Oil o( M^tstard (Oleum Sinapts, B. P.) is the suiphocyanal* of allyl (p. 36i). If adulterated with alcohol, its s^cific gravity is below 1.015. 36. Oil of l^arpentine ( Oleam Tere- hinihmcB, B. P. and U. S. P.). Turpentine itself is really an oieo- resin of about the consistence of fi^sh honey. It Sows naturally or by incision from the wood of most coniferous trees, larch (Larix Earopaa) rielding Venice Turpeiiiine, Abies balsamea furnishing OanadioM Tur^emtine, Balsam of Fir or Ganada, Balsam ( Tere- binthina Canadensis, B. F. and U. S. P.), Pisiachia terebinthus, the variety termed Ghian 7}ufrpmtine, and the Bimts palustris, Pinus ahies, and jRwimb 'pinaster affording American Turpentine, Terebivihus, U.S. P. Pinus maritima gives the French or Bor- daaus Turpentine. By distillation turpentine is separated into rosin at resin (which remains in the still), and essential oil of turpentine, often termed simply twrpeniine, spirit oft'urpentine, or "tur^a" (which distils over). Mixed with aUiaii to saturate r" " """
and redistilled, oil of turpentine furnishes rectified oil of turpentine. Under the influence of heat, chemical agents, or both, oil of turpen- tine (C^H,g) yields many derivatives of considerable chemical in- terests 31. Oil of Vcd^an-root (Valerianae Radix, B. P. and U.S.P.) (Oiewm Valeriance, U.S.P.) is a mixture of a hydrocar- bon (O^H^) and valerol (OjH,(,0). Talerol slowly oxidizes to valerianic acid, known by its smell. A similar change occurs at once if the oil of valerian be allowed to fell, drop by drop, on heated caustic potash: O,H,„O-l-3KHO-fHjO=K^O0,+K0^H,Oj+3H,. By the action of sulphuric acid on the yalerianate of potassium thus produced, valerianic acid is obtained. 38. Oil of Ginger (Zingiber, 32*
id .y Google
378 PATTY BODIES.
B. P, and U. S. V.) has the composition of h jdro«a oil of turpentine.
39. Wormseed (Ghenopodiwn, V. S. P.) contains a volatile oil.
40. Oil of Thyme { Oleum Tkymi, U. S. P.) is a mixture of thymene (Ci„Hi,) and thymol (Cit^,.0), asolid white crystalline body, llijmol is also contained in, 41, Oil of Horsemint [Monarda, U. S. P.).
Cahphobs. — III 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 CamphorOr offidnaru/m, or Camphor-Lanrel in Japan (termed, in Europe, Dutch camphor, because imported by the Dutch) and in China (known as Formosa camphor), by a rough process of distillation with water, and is resublimed in this country (Cam- phora, B. P. and U. S. P.). The formuhi of laurel-camphor is 0,^,80. The essential oil {Oleum Ga-mplwroB, "U. S. F.), from which doubtless camphor is derived by oxiM,tion, is easily obtained from the wood, and is occasionally met with in commerce under the name of liquid camphor or camphor oil; its formula is C^nHjjO ; by exposure to air it becomes oxidized and deposits common cam-
Shor, O^H„0+0=20i„HibO. There is another kind of camphor in luropean markets less common than laurel-camphor, but highly esteemed by the Chinese ; it is obtained from the Dryohtdanops aromatica, and denominated Sumatra or Borneo camphor. It differs slightly from laurel-camphor in containing more hydrogen, its for- mula being OioHuO. It is accompanied in the tree by a volatile oil (CioHij) isomeric with oil of turpentine. This oi! homehne, is also occasionally met with in trade under the name of licjuid camphor or cam^ltor oil, but differs from laurel-camphor oil in not depositing crystals on exposure ia air.
Camphor is soluble to a slight extent in water (40 grains per gallon, Pooley). The official Camphor-water {Aqua Gamphorte, B. P. and U. S. P.) or Camphor mixture, is such a solution.
CarUharidin (C^HaOj?), the active blistering principle of can- tharides (Canthandes, B. P., Cantharis, U. S. P.) and other vesi- cating insects, has most of the properties of a camphor or stearopten. It slowly crystalliaes, from an alcoholic tincture of the beetles, in fusible, voiatiie, micaceous plates. The following process for the extraction of cantharidin is by Ehimouze : 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 theu distilled, and the dark green residue treated with bisulphide of car- bon, which dissolves fato, resinous, and other matters, and precipi- tates the canUiaridin. The precipitate is thrown on a filter, washed with bisulphide of carbon, aiid recrystallized from chloroform. The same process, omitting the final recrystallization, may be used for the quantitative estimation of cantharidin in cantharides. The aver- age quantity found is from four to five parts in one thousand.
id .y Google
RESi;jS.
QUESTIONS AND BXBECISES.
812. How do volatile oils differ chemically from fixed oils?
813. What are the general chemical characters of volatile oils ?
814. Describe the iisual process by which volatile oils are ob- tained.
815. Mention the differences in composition between the volatile oils of Anthemis nobilis and Matricaria ckatnomilla.
816. Give the systematic name of oil of horseradish.
817. State the general composition of the oil of lemon, lime, berga- mot, citron, and cedra.
818. Name the constituents of oil of cloves.
819. In what respect does oil (or otto) of rosM differ from other volatile oils?
820. To what class of substances 6o the conBtitnents of oil of rue belong ?
821. How does natural turpentine differ from the tui^entine of trade?
823. "With what object is commereial turpentine rectified t
823. How is camphor oil related to campnor?
824. In what respects do Borneo or Sumatra camphor and cam- phor oil differ from the corresponding products of Japan and China?
825. What is the nature of cantharidin ?
EESINOID SUBSTANCES.
Resins occur in plants generally in association with volatile oils. They closely resemble camphors or stearoptens, but are not volatile, and differ from oils and fats mainly in being solid and brittle. Oleo- resins are mixtures of a, resin and a volatile oil. Gum-Resins are mixtures of a resin or oleo-reains and gum. Balsama are commonly described as resins or oleo-resins which yield benzoic or cinnaraic acid; but oleo-resins containing neither of these acids are often termed balsams, e. g. balsam of copaiva and Canada balsam.
Ebsjns.— 1. Besin, rosin, or colophony {Eesina, B. P. and U. 8. P.) is the type of this class. Its source is the oleo-resin or true tur- pentine of the conifers, a body which by dietillatiou yields spirit of turpentine and a residuum of rosin. The chief constituents of resin are pinie acid (HCj,H^O,l and sylvic acid, identical in composition, but differing in properties Uiide homerism), the former bein^ soluble and the iatf«r insoluble in alcohol of sp. gr. 0.883. Pinic aeid heated yields colophonic or colopholic acid. Among the products of the destructive distillation of resin, Tiohbome has recently found " colo- phonic hydrate" (OjpHjjOj, HjO), a white inodorous cr^talline sub- stance, and by depnving this of water obtained white crystalline colophonine (0|„IIj,O,). Eesin is soluble in oil of turpentine. It is a constituent of eight of the fonrteen Plasters (Emplastra) of the
id .y Google
380 RE aiNOID SUBSTANCES.
Britisli Pharmacopteia. 2. Arnicin, the chief acrid if not the only active principle of Arnica (Amiece Baddx, B. P., Amicce Floret, U. S. P.), is a resin. 3. Cannabtn, said to be the active principle of Indian Zfemp (Cannabis Indica, B. P., Extraetmn Cannabis, U. S. P.), is usually described as a resin. 4 Capsicv,m-fl-mt con- tains resin (p. 327). 5. Castorin, a resinous matter, is the name given to the chief constituent of Castor ( Castor&am, B. P. and U. S. P.), the dried preputial follicles and included secretion of the Beaver [Castor Fiber). 6. Ergotin is a verv active retinoid con- stituent of Ergot {Ergota, B. P. and U. S. P.), or "the sclerotium ^compact mycelium or spawn) of Claviceps purpurea, produced with- in the palese of the common rye, ^feccsZe cereaie. 1. Gruataeutn^esin is a mixture of several substances (p. 343). 8. Jalap^esin (p. 344), 9. KousBO (Cusso, B. P.) is said to owe its anthelmintic property to a neutral bitter acrid resin. 10. Mastie [Mastieke, B. P. andU. S. P.) is a resinous exudation obtained hy incision from the stem of the Mastic or Lentisk tree. Nine-tenths of Mastic is mastiokic acid (O^HjjOAa resin soluble in alcohol; the remaining tenth, maetimn f OjjHjiO), a tenacious elastic resin. 11. Mezereon, the dried bark {Mezerei Cortex, B. P. and U. S. P.) of Daphne meaerewm, Meze- reon, and Daphne laureola. Spurge Laurel, owes its acridity to a resin. 12. Pepper contains a resin (p. 329). 13. Burgundy Pitch [Pise Burgundica, B. P. and F. S. P.) is the melted and strained exudation from the stem of the Spruce Fir, Abie& Exeeka. The term Burgandy is a misnomer, the resin never having been collected at or near Burguudy ; Finland, and to a smaller estent Baden, and Austria being the countries whence it is derived. lis constituents closely resemble those of common Resin. It is often adulterated and imitated by a mixture of resin with palm-oil, water, &c., from which it may be readily 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). 14. Podophyllivm-resin (p. 327). 15. Pyrethrtn is the name of the acrid resinous aetive principle of Pellitory-root (Pyrethri Radix, B. P.). 16. The resins of Ehabarb have already been alluded to in connec- tion with Ohrysophanic acid (p. 277). 17. Rottlerin is the name given by Anderson to a crystalnne resin from Eamala (Kamala, B. P.), the minute glands that cover the capsules of RotUera tinctoria ; to this, and, apparently, allied resins, Eamala owes its activity as an anthelmintic.
Olko-essjws, — 1. Copaiva {Copaiba, B. P. and IT. S. P.) is a mixture of abont 40 per cent, of essential oil (C,5H,„), with two or more per cent, of brown soft resin, and 50 or more of a yellow dark resin termed Copaivtcadd {p^B.^Q,). Copaivaheated with a fourth of its weight of the ofBcia] carbonate of magnesium yields a transparent fluid, owing to the formation of copaivate of magnesium and solution of this soap in the essential oil. With an equal weight of the car- bonate enough soap is produced to fake 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 complete reaction is effected. Quicklime has a similar effect. Per-
id.y Google
aUM-RESINS. 381
s carbonate reacts more quiclily because of its fine state of di- un and admixture of hydrate — in which ease hydrates of oaloinm and magnesium may be expected to act better than the calcined pre-
giratJons, and in miicli smaller quantity than carbonate of magnesium, opaiva is soluble in its own bulk of benaol, and, unlike, 2, Wood- oil, a similar oleo-resiu from the Dipterocarpus tnrbinatus, does not become gelatinous when heated to 27(P P. Copaiva, also, is not fluorescent. 3. Elemi[Blemi, B. P.) is an exudation from an un- known tree (probably vanarivm commune). It consists of volatile oil with 80 or more per cent, of two reains, the one (CsjHjjO J solu- ble in cold alcohol, the other {0«,HuO} almost insoluble. 4. Wood- Tar (Pix Liguida, B. P. and U. o-V.) is a mixture of several resi- noid and oily bodies (amongst others Creasote, p. 363) obtained by destructive distillation from the wood of Finus sylvestris and other pines. When heated it yields a terebinthinate oil and a residue of pitch. 5. Turpentines. These oleo-resins have been mentioned in connection with oil of turpentine, their volatile, and resin, their fixed constituent. 6, Common Franlcincense (Thus Amerieanwm,B. P.) is the concrete tnrpentuie of Finiis tteda. 1. Canada Balsain (Tereiinihina Canatfensts, B. P.) is the turpentine or oleo-resin of the Balm of Gilead Fir {Aiies balsam^. 8. Sumbut^oot {Sum- bid Radio;, B. P.) seems to owe its stimulating property to two oleo-resins, one soluble in ether, the other in alcohol. 9. Oleo-resin of Lupvlin (TJ. S. P.) is an ethereal extract of the yellow powder {Lttp'ulma, U. S. P.) attached to the small nuts at the base of the scales which form the aggregate fruit of the Hop {Rumvius Liijiu- lus). It contains «^ential oil of hop and oxidised oil or resin. Oleoresinee Capsioi, Cubebce, Piperis and Zingiberis are also offi- cial in the United States Pharmacopceia. 10. Bix CaTiaderma, U. 8. P., is the concrete juice of Abies Canadensis.
GcM-KESiNS. — 1. Ammoniacum, [Ammordaeum, B. P. and 17. S. F.) is an exudation from the Borema Am/rtwniacifm. It contains nearly 20 per cent, of gum and about 10 of resin (OjjH^Ob— John- ston). 2. AasafcEtida (Amafoetida, B. P.) is a gum-resm obtained, by incision, from the living root of Narthex assafoetida. . It contains from 50 to 70 per cent, of resin, 25 to 30 per cent, of gum (abont two. thirds arabin, one-third baasorin, p. 85), and 3 to 5 per cent, of vola- tile oil. 3. Gamboge [Oamboma, B, P. and IT. S. P.) is obtained from the Gardnia mordla. When of best quality it contains from 20 to 26 per cent, of gum, and 80 to 7S per cent, of a rosin termed gambogic acid (O^a^O^). 4. OaHanwin {Oalbammt,'B.F.aaA v. S. P.) contains from 20 to 25 per cent, of gum, and about 65 per cent, of resin (OjjHjiOi), and 3 or 4 per cent of volatile oil. 5. Myrrh (Myrrha, B. P. and U. S. P,), an esudation from the stem of Balsamodendron myrrha, contains about half its weight of solu- ble gum (probably arabin), 10 per cent, of insoluble gum (probably basaoiin), 2i of volatile oil, and about 25 per cent, of resin (myrrhic acid). 6. Scatnmont/ (p. 346).
Gum-resins need only be finely powdered and rubbed in a mortar with water to yield a medicinal emulsion, in which the fine particles of resin are held in suspension by the aqueous solution of gum.
id .y Google
382 RESINOID SUD STANCES.
BALSi.M3.— 1. Benzoin {Benzoimim, B. P. and U. S. P.) is ob- tained from incisions of tlie batk of Styrax benzoin. It contains 12 to 15 per cent, of benaoic acid (p. 276), abont 50 per cent of a resin (a) Bolnble in ether, 25 to 30 per cent of a resin (3) soluble in alcoliol only, and 3 to ^ per cent, of a, resin (y) soluble in solution of carbonate of sodium. The a resin is consideved to be a compound of the (3 (C«,H„0,) and the y (OjoH^Oj). The balsams of Fere, Tolii, and Storas &Set from benzoin in containing cinnamic (ji. 377) in place of benzoic acid; hence they yield, by oxidation, hydride of benzoyl (oil of bitter almondsV 2. Balsam of Peru {Balsamwat Peruvianum, B. P. and U. S. P.), from the Myroxylon Pefeircs, ia a misture of 70 per cent, of oily with abont 23 .of resinous matter, and 6 per cent, of cinnamic acid The oil (cinnamfiin), by action of potash, yields cinnamic acid (HC^H^O,) and cinnamic alcohol (HCsHjO), otherwise known as _pe?T*j;me or styrone; it also often holds in solution metaoinita'ntgm or styraein (0.,H|nO,), isomeric with hydride of cinnamy! (0,H,OH). The resin of balsam of Fern seems to result from the action of moistnre on the oil. ITie constit- nents of Varnlla, U. S. P., somewhat resemble those of Balsam of Pern. 3. Balsam of Tolu (BcUsamtm, Tolutanum, B. B. and U. S. P.) is an exudation from incisions in the bark of Myroxylon tolu- if era ; it closely resembles balsam of Pern, but is more susceptible of resinification. Old hard balsam of tolu is a convenient source of cinnamic acid, which is extracted by the same process as that by which benzoic acid is obtained from benzoin,' namely, ebullition with alkali, filtration, and precipitation by hj^drochlorie acid. 4 Storax is an oleo-resitt obtained from the I/iquidambaT orientate. It con- tains a volatile oil termed styrol (GgSg), cinnamic acid, styraein, and a soft and a hard resin. Styrol differs from similar hydrocarbons in being converted into a jKilymeric solid termed metastyrol or draconyl on the mere application of a temperature of about 400° F. For medicinal use, sterax (Styrax Prcepiiratus, B. P. and U, S. P.) is
Eurifled by solution in alcohol, filtration, and removal of the alconol y distillation.
Gaontchouc or Indior-rubber, and Qutta Percka.
■c / at a higher tem- perature a hard horny product, termed ebonite or vulcanite, results. Gutta Percka (U. S. P.) is the concrete drop or juice of the percka (Malay) tree, the /soJiainiraaw((a, and of other Sapotaceous plants. It is soluble in chloroform {Liquor Gutta-percha, V. S. P.), benzoyl, and essential oils.
These two elastic substances, in the pure state, are hjdrocarbons (ieOsH,), usually slightly oxidized.
id .y Google
QUESTIONS AND EXERCISES,
826. Distinguiah between resios and camphore. Mention the poinfg of difference of resins, oleo-resins, gnm-resins, and balsams.
827. Name tie constituents of common Resin.
828. Enumerate some ofBciat articles of which the active constit-
829. Give the chief distinguishing characters of Burguiidj Fitch.
830. What is the average proportion of oil in Copaiya ?
831. Explain the effect of magnesia or lime on eopaiva.
832. State the nature of Wood-Tar,
833. Why do Ammoniaciim, Asaafcetida, Gamboge, Galbannm, and Myirh give an emnlsion by mere trituration with water?
834. In what respect does Benzoin differ from (he EaUania of Peru, Tolo, and Storax ?
835. Wl^t is the chemical nature of Indiarmbber and Gntta Percha?
836. How is India-rubber vulcanized and convwvted into ebonite or vulcanite f
COLOEING-MATTEES.
The animal, vegetable, and mineral kingdoms abound in sub- stances or pigments which powerfully decompose light, absorbing certain of its constituent colors, and reflecting some others. Thus, for example, most leaves contain a body termed chlorophyll, which has the property of absorbing red light and reflecting sTeen; these reflected rays entering the eye of an observer, and striking on the retina (the expanded extremity of the optic nerve), always commu- nicate the same impression to the brain ; in popular language the leaf is said to be green. Art has added largely to the nnn^r of natural coloring-matters.
. Ybllow. — 1. Chrome-i/ellow occurs in more than a dozen shades (see Lead, ehromate of). 2. Fvstic or ydlow wood is the wood of the Rhus eotinue. 3. Gamboge (see Gamboge). 4 Ochre is met with of many tints, nnder the names of yellow ochre, qold yellow, gold earth or ochre, ffdloto sienna, chtfiese yellow. It is chiefly a mixture of oxyhydrates of iron with alumina and lime. 5. Orpt- ment is a sulphide of arseoieum (ASjSji. 6. Persian berries or Avig- non grains contain a principle termed chrysorhanmin (O-H^O,,). liey are tie product of the Rhamnus infectorius. 7. ^rree or Indian ydlow is said by Stenhonse to owe its color to purrate or euaianthate of magnesium (MgOj^a,0,2). 8. Querettron is the bark of Quercue finctoria, U. 8. P. or Black Oak. It contains the yellow glucoside, querdtrin (0,oH,,Oip,H„0). 9. Rhubarb (see Glirysophanic add, p. 217). 10. Saj^on {(frocue, B. P. and U. S. P.), the dried stigma and part of the stj'le of Crocus sativus, fields sajpranin or polychroite, a yellow principle whose chemistry is but little known. 11. Turmmc, the rhizome of Curcuma longa, owes
id .y Google
38i CO LOaiNO- MATTERS.
its yellow color to careitmin, a resinous matter. 12. Wdd [Reseda hUeola) contains a dnrable j^ellow niBtf«r termed Ivieolin (O-jHuOj). 13. Picric or earbaxotte acid (p. 364) ia a very powerful yellow dye.
Bbb. — 1. Alkanet, the root of Alkanna ttTioCoria, Tausch, Anr chastt tinetoria, Desf., yields anehusin {C„E^Og), a resinoid matter soluble in oils and fats. 2. Annatto or AmoUo, a paste prepared from the seeds of Bixa ordlana, contains hinnn, an orange-red, and orellin, a yellow principle. 3, JBrazil-ivood {GcBsalpinta branli- ensis) furnishes hreziHn, the basis of several lakes, Sapav^wood and Cam-tuooii probably contain the same substance. 4. Oinnabar, Chinese red, vermilion, or Paris red, is mercnric sulphide. 5. Ohrome-red is an oxyehromate of lead. 6. Cochineal {p. 271). 1. Madder, the root of Rabia tinctorvm, powdered and treated with sulphnrio acid and acidulated water to effect the remoTal of earthy and other inert matters, furnishes a residual powder termed garaib- tin. Garancin yields to pure water alizarin (Ci,H„0,, 3H„0), the red, nentral, crystallizable coloring-matter of madder. Alizarin does not exist ready formed in the plant, but is derived, by fermenta- tion, from rubian, a yellowish resinoid substance. 8. Mvlberry-juicc (JWomSmccms, B. B.) coniainB a violet-red coloring-matier which has not been chemically examined. 9. Red- lead (p. 170). 10. Red oxide of iron, of shades varying from light to brown red, is found native. The common names of it are Armenian bole, Berlin-red, col- cothar, English red, red ochre, burnt ochre, red earth, terra di sienna, mineral purple, stone red, and Indian red. 11. Red Sandal^wood {Pierocarpt Lignum, B. P. and U. S. P.), the billets and chips of Pterocarpiis santaiinus, owes its color to santalin (Oi„HigOj). a resinoid matter. 12. Bed-PoppT/ ^tals (Bhcedos Petula, B. P.), from the papaver rhceas, contains a red coloring principle which has not jet oeen isolated. 13. Red-Rose Petals (Rosce GaMicce Petala, B. P. and U. S. P.) also yield a red substance whicli has not been analyzed. 14. Saffiotoer or Bastard Saffron, the florets of CarfkiMmia tinctoritts, containB an unimportant yellow dye, and carihamin (Oi,HjjO,), an uncrystallizable red dye, the pigment of the old pink saucers. Mixed with French chalk, carthamin is used as a cosmetic under the name of vegetable rouge — carmine being animal rouge, and peroxide of iron mineral rouge. 15. Lao-dye is a cheap form of cochineal, and is also yielde»f by a species of Coccus. 16. Logwood (HcemaCov^li Lignum,, B. P,) contains a yellow substance, laemaiotxylin (C,jH„OaH.p or 3HjO), which, under the influence of air and alkali, assumes an intense red color. 17. Red enamel colors, for glass-staining and ceremic operations, are produced either by cuprous silicate or purple of Cassiua (p, 200).
Bins. — 1. Cobalt oxide precipitated in combination or admistnro with alumina or phosphate of calcium forms Th4nard'B blue, cobalt- blue, Hoffner's blue, and cobaltic ultramarine. 2. Smalt, Saxony ■ blue, 01 King's blue, are rough cobalt gbss in finepowder {p. 189). 3. Gopper-bhie, mountain-blue, and English or B^mbro' blue are carbonates or oxycarbonaf«s of copper. 4. Zndijo (p.239). 5, Lit- mus, lic}twirhlue, ti)/ms6le, orchil or archil, and cudbear are products of the action of air and alkalies on certain colorless principles, as
id .y Google
COLORING- M A XTKRS. 385
orcin (0,HflOj), derived from different species of lichen — Roccella, Variolaria, and Lecanora. 6. Prussian, blue (p. 280) and Turn- bull's blue (p. 281), tlie ferro- and ferridcyanidea of iron, are met with nnder the names of Erlangen, Louisa, Saxon, Paris or Berlin blue. 7, Ultramarine is made ou a lar^ scale by roasting a mix- tnre of fine white clay, carbonate of sodium, snlphur, and charcoal. Its constitatiou is not well made oat Acida decompose it, sulphu- retted hydrogen escaping.
Grekm. — 1. Cupro-arsemcal green pigments (p. 136). 2. Chlo- rophi/U, Leaf-green, or Chromule. A method of extracting chlo- rophyll is given on p. 406. It is of a resinoid nature, soluble iu ^cohol and ether, but insoluble in water, and, according to Fr^my, consists of a blue Babstance, phylloci/amn (OjjHsjNjO,;?), and a yaWow, phylloxanthin; the yellow tints in fading autumnal leaves, he says, ace due to the latter principle, the former being the first to fade. 3. Sap-gre&n, bacMhom; vegetable-, or bladder-green, is obtained by evaporating to dryness a mixture of lime and tne juice {Bhamni Succus, B. P.) of the berries of the Buckthorn (Ehamnus catharticus). It is soluble in water, slightly in alcohol, and insolu- ble in ether aad oils. 4. Green ultramarine is made by a process similar to that for blue ultramarine. 6. Mixtures of blue and yellow pigments and dyes are common sources of green colors. 6. Glass "d earthenware are colored green by oxide of chromium and black
By heat it is darkened in tint, and is then known as burnt umber. It is a mixture of oside of iron, silica, and alumina. 2. Sepia is a dried ftnid from the ink-bag of cuttlefishes (Sexpiadte) ; by its ejection into adjacent water the anima! obtains opportunity of escape from enemies. 3. Catechu (p. 29S) furnishes a brown coloring-matter,
Blaos. — 1. BlacMead (p. 26), boTie-Uack (p. 82), or ivoryMack and lampblack, the latter a deposited soot from the incomplete com- bustion of resin and tar, are varieties of carbon. 2. Bwrjii sugar or caramel (p. ZTl). 3. TndioM ink is usually a dried mixture of fine lampblack and size, or thin glue. 4. Black ink is essentially tannates and gallates of iron suspended in water containing a littie gum iu solution. 5. Priniefs ink is well boiled linseed or other oil, mixed with good Inmpblack, vermilion, or other pigment. 6. Black dyes are of the same nature as ink.
White Pigments. — 1. Chalk or Whiting (p. 82), 2. French chalk, steatite, or soapstone, a silicate of magnesium. 3. Heavy white {p. 75). 4 Pearl-white (p. 206). 5. Plaster nf Paris (p. 78). 6. Starch (p. 5i8). 7. White lead (p. 168). 8. Zinc-white (p. 99). 9. Oxides of tin and zinc and phosphate of calcium are employed for giving a white opacity to glass.
Akilinb Colors. Coaliar colors. — Within the last ten years nearly every shade of color seen in the animal or vegetable kingdoms has been successfully imitated by certain dyes and pigments primarily derived from a mineral, coal. Goal distilled for gas furnishes tar or gas-tar. Ooai-tar contains some aniline ; but especially it contains a liquid convertible into aniline, namely beuzol (CjHjH), first discovered 33
id .y Google
386 CHEMICAL TOXICOLOGY.
by Faraday in compressed oil-gas. From anilitip, by osi<btion, EuQge obtained the violet color-reaction, the body producing which Ferkin afterwards studied and isolated, and luanafaclnred nnder tlie name of inauve. Aniline^ed [fuchsine, inagenta, or roseaitUine), aniline-yelloio, aiiilme-green, OMtline-blue, and, in short, aniline-dyea, lakes, and pigments of every hae of the rainbow, are now common articles of trade. Their application has revolutionized the arts of the dyer and eolot-priiiter.
QUESTIONS AND EXERCISES.
SSI. Explain the production of color.
838. Mention the chief yellow coloring-matters.
839. What is annatto ?
840. Name the colorific constituent of madder.
841. State the source of Litmus.
842. Ddstingnish between Prussian bine and Tunibull's blue,
843. How is bine ultramarine obtained?
844. Describe the coloring principle of green leaves,
845. By what agents is glass colored green ?
846. Whence is sepia obtained ?
847. Describe the chemistry of black ink.
848. Write a few sentences on aniline colors.
CHEMICAL TOXICOLOGY.
In cases of criminal and accidental poisoning, the substances pre- sented to the chemical analyst for examination are usually articles of food, medicines, vomited matters, or the liver, kidney, intestines, stomach and contents, removed in course of postmortem examina- tion. In tiese cases some special operations are necessary before the poison can be isolated in a staf« of sufficient purity for me applica- tion of the nsual tests; for in most instances the large quantity of animal and vegetable, or, in one word, organic matter present pre- vents or masks the characteristic reactions on which tne t«sts are founded. These operations will now be described;* they form the chemical part of the subject of Toxicology (I't^noF, toadcon, poison, and idyoj, logos, discourse). Substances occurring in the form of an apparentlydefinitesalt ornnmised withorga natte n in p cM treatment, they are analyzed by the o d na y m th d al ady given, attention bemg restricted to poisonou mpo d niy
* Materials for these experiments are read !y bt d f da
tional parposea by dissolving the poison ii uf n f t a ft
porter, or !u water to which some muoilage of t h In d m I pieces of bread, potato, and fat, have been added.
id .y Google
MERCURY, ARSENIUM, ANTIMONY, ET
Examination of an oroanio mixture suapBCTBD to con- tain : Mercury, Arsenicum, Antimony, Lead, or Cop- per ; Sulphuric Acid, Nitric Acid, Hydrocri.oeio Acid, Oxalic Acid, or Hyorooyanic Acid; Strychnia ok Morphia.
FreHminafy Examination.
Odor, Appearance, Taste. — Smell the mixture, with the view of ascertaining the presence or absence of any nota- ble quantity of free hydrocyanic acid. Look carefully for any small solid particles, such as arsenic, corrosive subli- mate, or verdigris, and for any appearance which may bo regarded as abnormal, any character unusual to the coffee, tea, beer, medicine, vomit, coats of stomach, kidney, liver, or other organ, tissue, or solid matter under examination. If liquid or semifluid, taste the mixture, or add to a small portion some solution of carbonate of sodium, with the view of ascertaining by excessive sourness or strong effer- vescence the presence of any large, poisonous quantity of sulphuric, nitric, or hydrochloric acid.
If this preliminary examination does not indicate the method to be pursued, proceed as follows, treating a por- tion (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 in the course of the analysis.
Examination for Mercury, Arsenicum, Antiviony, Lead, Copper, Zinc.
If a liquid, acidulate with hydrochloric acid and boil for a short time. If solid or semisolid, cut up the matter into small pieces, add enough water to form a fluid mixture, stir in ten or twenty per cent, of ordinary liquid hydrochloric acid, and boil until, from partial aggregation and solution of the solid matter, filtration can be easily effected.
Heat a portion of the clear liquid with a thin piece of bright copper or copper gauze, about an inch long and a quarter of an inch broad, for about ten or twenty minutes ; metallic mercury, arsenicum, or antiinony will be deposited on the copper, darkening it considerably in color. Pour off the liquid from the copper, carefully rinse tlie latter with a little cold water, dry the piece of metal by holding
id .y Google
388 CHEMICAL TOXICOLOGY.
it over or near a flame (using fingers, not tongs, or it may hecome sufficiently hot for loss of mercury or arsenicum to occur by volatilization), introduce it into a narrow tQSt- tube or piece of glass tubiDg closed at one end, and heat the bottom of the tube in a flame, holding it horizontally that the upper part of the tube may be kept cool, and par- tially closing the mouth with the finger to prevent escape of vapor. Under these circumstances any Mercvry will volatilize from the copper and condense on the cool part of the tube in a ring or patch of white sublimate, readily aggregating into visible globules on being pressed by tlie. side of a thin glass rod inserted into the tube ; Arsmiicum will volatilize from the copper, and, absorbing oxygen from the air in the tube, condense on the coo! part of the glass in a ring or patch of white sublimate of arsenic (gray or even darker if much areeuieum as well as arsenic he pre- sent), not running into globules when rubbed, but occur- ring in small crystals, the characteristic oct^edral form of which is readily seen by aid of a good hand lens, or the lower part of a microscope ; Antimony volatilizes from the copper, if strongly heated, and, absorbing oxygen, immedi- ately condenses as a slight white deposit close to the metal. Confirmatory Tests. — 1. Nothing short of the prodaotion of
floboles should be accepted as evidence of the presence of mercury, t will usually have existed as corrosive sublimate.
2. To confirm indications of the presence of arsenicum, a portion of the acid liquid may be subjected to the hydrogen tests (pp. 133, 135) ; or the tube containing the white crystalline ai-senic may be broken, and the part on which the sublimate occurs boiled for some time in water, and the hydrosolphuric-acid, ammonio-nitrftte-of-silver, and ammonio-sulpbate<hf-copper teste (pp. 135, 137} applied to the aqneons solution.
3. For antimony, a portion of the acid liquid must always be intro- duced into the hydrogen-apparatus with the usual precautions. ( Vide p. 144.)
For Lead and Copper, pass hydrosulphuric acid gas through the clear acid liquid for some time, warming the liquid if no precipitate is produced, or diluting and par- tially neutralizing the acid by 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 the tests, ammonia for copper, sulphnric acid for lead, and any other of the ordinary reagents (pp. 151, 111).
Copper may often be at once detected in a small quantity of acidulated liquid by iiimievsing the point of a penknife or a piece of
id .y Google
MINERAL ACIDS, OXALIC ACTDS, ETC. 389
bright HOB nire — a leprs t rf copj or in t'l characteristi color, quickly oi slowly apptirng accurding tu the Amount present (p.
Zin-c — To the aeid litjuid through which suljihuretted hydrogen has beeu passed, add excess of immoni^ (or to the original acid fluid add excess of ammonia, and then sulphydrate of ammonium) ; a precipitate falls which may contain alumina, phosphates, and zinc; it is usually black- ish from the presence of sulphide of iron. Collect the precipitate on a filter, wash, dissolve in a little hydro- chloric acid, add a few drops of nitric aeid, boil, pour in excess of ammonia, filter, and test the filtrate with sul- phydrate of ammonium — a white precipitate indicates zinc.
Examination for Mineral Acids, Oxalic Acid, or Hydrocyanic Acid.
To detect Hydrochloric, Nitric, or Sulphuric Acid in any liquid containing organic matter, dilute with water and apply to small portions the usual tests for each acid, disregarding indications of small quantities. ( Vide pp. 222, 231, 25T.)
BxoeBBive sourness, copious evolution of carbonic acid gaa on the addition of carbonate of sodinm, and abundant evidence of avid on applying the various tests to small portions of the fluid presented for analysis, collectively form sufficient evidence of the occurrence of a poisonona wnouat of either of the three common mineral acids. Small quantities of the hydrochloric, nitric, and sulphuric radicals occurring as metallic salts or acids, are common normal constituents of food, hence the direction to disregard insignificant indioationa. If the fluid under examination is a vomit or the contents of a stomach, and an antidote has been administered, free acid mil not be found, but, instead, a large amount of corresponding salt.
For Oxalic Acid, filter or strain a portion of the liquid, if not already clear, and add solution of acetate of lead so Jong as a precipitate occurs ; collect the precipitate, which is partly oxalate of lead, on a filter, wash, transfer it to a test-tube or test-glass, add a little water, and pass hydro- sulphuric gas through the mixture for a short time ; the lead is thus converted into the insoluble form of sulphide, while oxalic acid is set free in the solution. Fitter, boil to get rid of hydros ulph uric gas, and apply the usual tests for oxalic acid (see p. 262) to the clear filtrate.
For Hydrocyanic Acid, the three chief teats may be ap- plied at once to the liqiiitl or aemiliquid organic mixture,
id .y Google
390 CHEMICAL TOXICOT, OOY.
whether it has an odor of hydrocyanic arid or not. First : half fill a small porcelain crucible with the material, add eight or ten drops of strong 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 nitrate of silver; a white film on the silver solution is probably cyanide of silver, formed by the action of the gaseous hydrocyanic acid on the nitrate of silver. Second : prepare a small quantity of the organic mixture as before, slightly moistening the centre of the watch-glass with solution of potash ; here again the heat generated by the action of the strong acid is sufficient to volatilize some of the hydrocyanic acid, which, reacting on the potash, forms cyanide of potassium. On removing the watch-glass and stirring into it successively solution of a ferrous salt, a ferric salt, and hydrochloric acid, flocks of prassian blue are produced if hydrocyanic acid ia present. Third: pro- ceed as before, moistening the watch-glass with sulpbydrate of ammonium ; after exposure to the hydrocyanic gas for five or ten minutes, add a drop of solution of ammonia,- evaporate to dryness at a low temperature, and add a drop of hydrochloric acid and of solution of perchioride of iron ; a hlood-red color, due to sulpJiocyanate of iron, ia pro- duced if cyanogen is present.
If the above reactiona are not well marked, the organic mixture m&j be carefally and slowly distilled in a small retort, the neck of which passes into a bottle and dips beoeath the surface of & little water at the bottom of the bottle, and the reagents then applied to sepiratc 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 is usually destroyed.
Examination for PJiospIioi'its.
A paste containing phosphorus is commonly employed for destroy- ing vermin. In cases of poisoning the phosphorus is usually in suffi- cient quantity to be recognized by its cnaracteristic unpleasant smell. A stomach in which it occurs not unfrequently 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 by snlphnrio acid added, a long wide glass tube fitted to the neck of the flask by a cork, and the mixture gently boiled. If phosphonis is present {even 1 part in 2,000,000, according to De Vry) the top of the column of steam as it condenses in the tube will appear distiuctiy
id .y Google
BTRYOHNIA — MORrillA. 391
phospboresceut ivlien viewed in a dark room. From its liability to oxidation phiKphorus cannot be detected after niucii exposure of an organic mixture to air.
Examination for Strychnia and Morphia.
Strychnia. — If solid or semisolid, digest the matter with water and about 10 per cent, of hydrochloric acid till fluid, filter, evaporate to dryness over a water-bath. If the organic mixture is already liquid, it is simply acidulated with hydrochloric acid and evaporated to dryness. The acid residue is next treated with spirit of wine as long as anything is dissolved, the filtered tincture evaporated to drj'ness over the water-bath, and the residue digested in water and filtered. This slightly acid aqueous solution must now be rendered alkaline by ammonia, and well shaken in a bottle or long tube with about half an ounce of chloroform, and set by till the chloroform has subsided. The chloroform (which contains the strychnia) is then removed by 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 concentrated sulphuric acid, and the basin kept over the water-bath for several hours. (It is highly important that the sulphuric acid used in this operation should be free from nitrous compounds. Test the acid, therefore, by adding powdered sulphate of iron, which becomes pink if nitrous bodies are present. If these are found, the acid should be purified by strongly heating with sulphate of ammonium, seventy or eighty 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 tlie chloroform to separate, and the chloroform again removed. If on evaporating a small portion of this chloroform solu- tion to dryness, adding a drop of sulphuric acid to the residue, and warming, any darkening in color or charring takes place, the strychnia is not sufficiently pure for chem- ical detection; in that case the rest of the chloroform must be removed by evaporation, and the residue redigested in warm sulphuric acid for two or three hours. Dilution, neutralization of acid by ammonia, and agitation with chloroform is again practised, and the residue of a small portion of the chloroform solution onco more tested with sulphuric acid. If charring still occurs, the treatment
id .y Google
303 CHEMICAL TOXICOLOGY.
must be repeated a third time. Finally a part of the chlo- roform solution is taken «p by a pipette, and drop after drop evaporated on odb spot of a porcelain crucible-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 red chromate of potassium placed in the second drop, and when the acid has become tinged with the chromate, one drop drawn across tlio other ; the characteristic evanescent purple color is then seen, if strychnia is present. Other tests {vide p. 324) may be applied to similar spota.
This is Girwood and Rogers's method for the detection of strych- nia when mixed with organic matter. It is tedious but truatworthy, and, though apparently complicated, very simple in principle; thna strychnia is soluble in acidulated water or alcohol, or in chloroform, readily removed from an alkaline liquid by agitation with chloroform, and not charred or otherwise attacked when heated to 212^ F. with sulphuric acid : much of the organic matter of the food is insoluble in water; of that soluble in water, much is insoluble in alcohol; and of that soluble in both menstma, all is charred and destroyed by warm sulphuric acid in a shorter or longer time.
Morphia, and the Meoonic Acid with which it is asso- ciated in Opium. — To the liquid or the semifluid mixture warmed for some time with a small quantity of acetic acid, filtered, and concentrated if necessary, add solution of acetate of lead until no further precipitate is produced. Filter and examine the precipitate for meconic acid, reserv- ing the filtrate for the detection of morphia.
The Precipitate. — Wash the precipitate (meconate of lead, &c.) with water, place it in a test-tube or test-glass with a small quantity of water, pass hydro sulphuric acid gas through the mixture for a short time, filter, slightly warm in a small basin, well stirring to promote removal of excess of the gas, and add a drop of neutral solution of perctiloride of iron ; a red color, due to the formation of meconate of iron, is produced if meconic acid is present. This color is not destroyed on. boiling the liquid, as is the case with ferric acetate, nor is it bleached by solution of corrosive sublimate, thus distinguishing it from the ferric sulphoejanate. It is discharged by hydrochloric acid.
The Filtrate. — The solution from which meconic acid has been removed by acetate of lead is evaporated to a small bulk over a water-bath, excess of carbonate of potassium added, and evaporation continued to dryness. The residue is then treated with alcohol, which dissolves the morphia. The alcoholic solution evaporated similarly may leave the
id .y Google
CHEMICAL TOXICOLOGY. 393
morphia siiflicientlj' pure for tbe application of the usual tests (vide page 3J8) to email portions of the residue. If no reaction is obtained, add a drop of snlpbnric acid and a little water to the residue and shake with ether, in which the salt of morphia is insoluble. The treatment with ether may be repeated until nothing more is removed, the acid aqueous liquid saturated with carbonate of potassium, the mixture evaporated to dryness, tbe residue digested in al- cohol, filtered, and portions of the alcoholic liquid evapo- rated to obtain spots of morphia for the application of the ordinary tests.
The examiBatioa for morpliia must be conducted with great care, aud witli as large a quantity of material as can be spared ; for its isolation from other organic matter ia an operation of considerable difficnlty, especially when only a minute proportion of alkaloid is present. Fortunately the detection of meconio acid does not inclade similar diOicQlties ; and as its reactions are quite characteristic, its preeence is held t* be strong evidence of the existence of opiam in an organic mixtui^.
ANTIDOTES. Vide "Antidotes" in the Index.
QUESTIONS AND EXERCISES.
849. In examining food and similar matter for poison, why mnst not the ordinary teats for the poison be at once applied 1
850. What preliminary operations shonld be performed on a vomit in a case of suspected poisoning?
851. How wotdd you proceed in searching for corrosive sublimate
852. By what seriw of operations would you satisfy yourself of the presence or absence of arsenic in the contents of a stomach ?
853. Describe the treatment to which decoction of coffee should be subjected in testing it for tartar-emetic.
854. Stat« the method by which the occurrence of lead in water is demonstrated.
855. Give a process for the detection of copper in jam.
856. How may the presence of a poisonous quantity of sulphuric acid in gin be proved ?
857. In examining ale for free nitric acids what reactions would he selected?
858. Show how you would conclude that a dangerous quantity of hydrochloric acid had been added to cider.
859. Describe the manipulations necessary in testing for hydro- cyanic acid in the contents of the stomach.
860. By what method is oxalic acid discovered in infusion of coCTee 7
id .y Google
394 M0RB1I> 13RINE.
861, Give the process by which atrychiiia is isolated from par- tially digested food.
862, Mention the ezperiments by which the presence of laudanum in porter is demonstrated.
863, Name the appropriate antidotes in cases of poisoning by: a, alkaloids; b, antimoniaJs ; c, arsenic; d, barium salts; e, copper ■■" * ' "Irochloric acid; g, hydrocy ' ■> *
orrosive sublimate; j, nitr (, oil of vitriol ; n, tin liqm:
EXAMINATION OF MORBID URINE AND CALCULI.
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 ounces in 24 hours) in the form of carbonic acid gas, aud 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 car- bonic acid gas. The feces consist mainly of the insoluble dihria of the system, the soluble matters and water forming the urine. These excretions vary considerably, according to the food and general habits of the individual and external temperature. But in disease the variations become excessive; their detection by the medical practitioner, or by the pharmacist for the medical practitioner, is therefore a matter of importance.
A complete analysis of feces, urine, or expelled air cannot be performed in the present state of our knowledge. Nor can any analysis of feces or air be made with sufficient ease and rapidity to be practically available in medical diagnosis. But with regard to urine, certain abnormal subatances and abnormal quantities of nor- mal constituents may be chemically detected in the course of a few minutes by any one having already some knowledge of chemical manipulation.
Healthy Human Urine contains, in 1000 parts, 957 of water, 14 of urea, 1 of uric acid, 15 of other organic matter, and 13 of inor- ganic salts.
Examination op Morbid Urine for Albumen, Sugar,
AND EXCESS OP UrEA ; AND TJrINARY SeDIMENT FOE
Urates (or Lithatbs), Phosphates, Oxalate of Cal- cium, AND Uric Acid.
Albumen. — To defeet albnmen, aeidulhte a portion of the clear urine in a tesl-tiibe with a few drops of at'otic
id .y Google
ALBUMEN — SIFOAR — UREA. 395
acid (to keep phosphates in solution) and boil, flocks oi coagnta will separate if albumen be present.
This experiment should first be made on normal urine lontaming' a drop or two of solation of white of eg^. A eoagulum tf puie albumen is white, greeEJsh if biie pigment is present, and brownish red if tiie urine contains blood. The influence of acids and alkalies on the precipitation of albumen is noticed on page 366.
The occurrence of albumen 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.
Sugar. — To a portion of the clear urine in a teet-tube add five or ten drops of solution of sulphate of copper ; pour in solution of potash or soda until the precipitate first formed is redissolved; slowly heat the solution to near the boiling-point : a yellow, yellowish-red, or red precipi- tate (cuprous oxide) is formed if sugar is present.
This experiment should first be made on nrine containing a drop >r two of solution of grape-sugar (page 338). The hydrate of eop-
i, but readily dissolves if organic matters, especiwiy sugar, h present. The copper salt must not contain iron. Other teats may be applied if nec^sary (vide page 338.) A minnle amount of sugar is said to occur in normal urine and a distinct trace is ocoasionatlj present. In larger quantities it is a characteristic constituent of the urine of diabetic patients.
Excess of Urea. — Nearly one-half of the solid matter in the urine is urea. Its proportion varies considerably ; but 1^ per cent, may be regarded as an average amount. Con- centrate nrine sliglitly by evaporation in a small dish, pour the liquid into the test-tube, set the tube aside till cold, or cool it by letting cold water run over the outside, add an equal bulk of strong nitric acid and again set aside ; scaly crystals of nitrate of nrea are deposited more or less quickly.
With regard to the amount of urea in urine, i sharply define excess or deficiency. If nitric acid gives crystals without concentration, excess is certainly jpresent. A rough estimate may be formed by mixing a few drops of the urine and acid on a piece of glass and setting aside; the time which elapses before crys- tals form is an indication of the quantity in the specimen. The time will vary according to the temperature and state of moisture of the atmosphere ; but with care some useful comparative results may in this way be obtained.
resfs,— Urea in solution in water may be detected by the above reaction with nitric acid, and by the readioess with which it yields ia on being boiled with alkalies. In putrid urine its conver- 0 an ammoniacal salt has already been eflected.
id .y Google
CIT,N,0 4- 2H3O = [NHJXOj. Fo'i-mrda, 0/ Urea. — The empirical fovinula of urea is OHjNjO.
(ooyi
Its rational formula may be thus nnttpn — II >N,; that is, H,i
it may be regarded a:
a primary diamine, it
place of Hj. The other atoms of hydrogen may be displaced by
various radicals, aud many comvotmd uieae be thus obtained.
Artificial Urea. — Urea may be prepared aitifioially by Williams's modification of Wohlei''a method. Cyanide of potassium, of the beat commercial quality (containing about 90 per cent, of rea! cyanide), is fused at a yery low red heat in a shallow iron yessel ; red lead is added in small qnantitiea at a time, the temperature being kept down b^ constant stirring. When the red lead ceases to cans* fur- ther action the mixture (cyanate of potassium and lead) is allowed to cool, the product finely powdered, exhausted with eold water, nitrate of barium added till no more precipitate (carbonate of ba^ rium) falls, the mixture filtered and the filtrate treated with nitrate of lead HO long as cyanate of lead is thrown down. The latter is thoroughly washed, and dried at a low temperatnre. Equivalent (luantifles of cyanate of lead and sulphate of ammonium digested in a small quantity of water at a gentle heat and filtered yield a solu- tion from which urea crystallizes on cooling.
Another process. — BasarofT has found that urea is produced when ordinary carbonate of ammonium is heated in hermetically sealed tubes to about 275° F. for a few honrs. The same chemist had pi-e- viously obtained urea by similarly heating pure carbamate of ammo- nium, so that the source of the urea in the former case is probably the carbamate of ammonium believed to occur in the carbonate [see page 67).
NI-T.NIIXO, — IT.O = CII.N.O.
id .y Google
IT EI NARY Sediments. Wai-m the sediment witt the supernatant urine and filter.
|
Insoluble. Phosphates, oxalate of calcium, and uric acid. Warm with acetic a«id, and filter. |
Soluble. Uratea — of ammoni- um, calcium, or so- dium, chiefly the latter. |
||
|
Insoluble. Oxalate of calcium and oric acid. "Warm with hydrochloric acid, filter. |
Soluble. PhospUatea, Add ammo. nia, white ppt. = phosphate of calcium, or |
ed OS the liquid cools, and if sufficient in anantity may be fur- ther examined for am- monium, calcium, so- dium, and the uric radical by the appro- |
|
|
Imoluhh. Xlric acid. rexid test (p. 297). |
SoluUe. Oxalate of cal- May b^ re- precipitated by |
nesium phos- phate, or both. |
priate tests. |
-Urina
■e seldom of a complex character; the
„ . _ f heat and ace'tic and hydrochloric acids generally at c
nd ate the character of the deposit, rendering filtration and pre- p tat n unnecessary.
Tk u ates are often of a pink or red color, owing to the presence of a pigment termed purpurine ; hence the common name of red
fravd for such deposits. Purpuritie is soluble in alcohol, and may e remoTcd bv digesting a red deposit in that solvent. It is seldom necessary to determine whether the urate be that of ammonium, cal- cium, OF sodium {see also Uric Acid, page 296).
The phosphate of ealciuw and the ammonio-magnestum phos- phate are usually both present in a phosphatic deposit, the magne- sium salt forming the larger proportion. They may, if necessary, and if sufficient in quantity, be separated by collecting on a filter, washing, and boiling with solution of cai-bonate of sodium. The carbonates of calcium and magnesium thus formed are collected on a filter, washed, dissolved in a drop or two of hydrochloric acid — chlo- ride of ammonium, ammonia, and carbonate of ammonium added, the mixture boiled and filtered ; any calcium originally present will then remain insoluble as carbonate of calcium, while any magnesium will be repreoipilated ftom the filtrate as ammonio-ma^esian phos- phate on the addition of phosphate or sodium, the mixture being
also well stirred. The chief portion of excreted phosphates is car-
34
id .y Google
398 MOKBTD URINE.
ried off by the fseces, that remaining in the nrine being kept in solu- tion by the influBnce of aeici phosphate of sodium, and, freqaently,
lactic acid. Occasionally, an hour or two after a hearty meal, the
urine becomes sufficiently alkaline for the phosphates to be deposited,
and the urine when passed is turbid from their presence. The am-
moniacal constituent of the magnesium salt does not occur normally, but is produced from urea as soon as urine becomes alkaline.
Oxalate of ctdniwm is seldom met with in excessive amounls, but very often in small quantities mixed with phosphates.
Free uric add is in most cases distinctly crystalline, and nearly always of a yellow, red, or brown color.
Artificial Sediments, — For educational practice, artificial deposits may be obtained as follows ; 1. Eub up in a mortar a few grains of serpent's excrement (chiefly urate of ammoniura) with an ounce or two of m;ine ; this represents a sediment of urates. 2. Add a few droj«of solution of chloride of calcium and of phosphate of sodium to urine ; the deposit may be regarded as one of phosphates. 3. To an ouuce or two of urine add very small quantities of chloride of calcium and oxalate of ammonium ; the precipitate is oxalate of cal- cium. 4. To urine acidulated by hydrochloric acid add a little ser- pent's excrement; the sediment is uric acid.
Other deposits than the foregoing are occasionally observed. Thus hippuric acid (HOgHaNO,), a normal constituent of human urine, and largely contained in the urine of herbivorous animals, is some- times found associated with uric acid in urinary sediment^ especially in that of patients whose medicine contains benzoic acid (p. 219J. Its appearance, as observed by aid of the microscope, is characteristic — namely, slender, four^ided prisms, having pointed ends. Cyatin (CjH,N80j) (from xia^tis, ftilsii's, a bladder, in allusion to its origin) rarely occurs as a deposit in urine. It is not soluble in warmed urine or dilute acetic acid, and scarcely in dilate hydrochloric acid, hence would be met with in testing for Iree uric acid. It is very soluble in ammonia, recrystallizing from a drop of the solntion placed on a piece of glass in characteristic microscopic six-sided plates. Oraan- tzed sediments may be due to the corpuscles of pus, mucus, or blood, fat-globules, spermatozoa, cylindrical oasts of tbe tubes of the kid- neys, epithelial cells from the walls of the bladder, or foreign matters, such as fibres of wool, cotton, small feathers, dust; these are best recognized by the microscope, as will be seen by the following para- graphs and figures on the microscopic appearances of both crystal- line and organized urinary sediments.
Microscopic Biamimation op Ubinart Skdimbnib.
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 and covered with a piece of thin glass and examined under the microscope with different magnifying- powers.
id .y Google
tTRlSARY SEDIMENTS
399
The respective appearances of the Tariona crystalline and organized matters are given in the following figures, which were drawn from natural apecimena (as seen with a two-third inch objective and No. 1 eye piece, i. e., magnified 60 diameters) in the collec- tions of 8t. Bartholomew's Hospital, H. B. Brady, F. L. S,. Dr. Sedgwick, W. W. Stoddart, F, 0. 8., Mr. Waddington, and the Author. Uric ^ci'rfoccarfl in many forms most of which are given in the
firat two figures. Flat more or le&a oval crystals sometimes attached
to each other, their outline then resembling ai common. Single and grouped quadratic prisma, a;_ and crystals recalling dumb-bells are met with. From ui by hydrochloric aoid, square crystals, two opposite sides smooth and two jagged, are generally deposited : acidulated by acetic acid more typical forms are obtained. A drop of solution of potash or soda placed on a glass slip will dis- solve a deposit of uric acid, a drop of any acid reprecipitating it in minute but cuaracteriatio crystals.
Cystin is very rarely met with as a urinary deposit; that from which the figure was talsen was found in the urine of a patient in St Bartholomew's Hospital. Lamellfe of cystin always assume an hexagonal character; but the angles are sometimes ill defined and the plates superposed : in the latter case, a drop of solution of am- monia placed on the glass at once dissolves the deposit, well-mavked as the drop dries up.
■sided crystals appearing
id .y Google
400 MORBID URINE.
Triple Phosphate (phosphite of mag-ne&iom and ammonium) la deposited as soon as urine tecomes ilkalme, the ammoniacal coniti tnent bemg furoished by tlie decomposition of urea It occurs in large prismatic crys- taJs fonning a beautilul object when viewed by polarized light — sometimes also iu ragged stellate or arborescent crystals, resembling those of snow. Both forms may be artificially pre- pared by adding a small lump of carbonate of ammonium tfl a few ounces of urine set aside in a test-glass. A fnorphoiis deposits are either earthy phosphates (a mixtoKot phosphates of magnesium and calcium) or urates (of calcium, magnesium, ammonium, potas- sium, or sodium — chiefly the latter). Thev may be distinguished by the action of a drop of acetic acid placed near the sediment on the glass slip, the effect being watched under the microscope; phos- phates dissolve, while urates gradually assume characteristic forms of uric acid. Urates redissolve when warmed with the supernatant
Urates of Sodium and Magnesiimn, though generally amorphous, occasionally take a crystalline form — bundles or tufts of small needles — as shown in the cot.
Oxalate of Calcium, commonly occurs in octahedra requiring high magnifying power for their detection. The crystals are easily over- looked if other matters arc pre- sent, but are more distinctly seen after phosphates have been re- moved byacetic acid. In certain aspects the smaller crystals look like square plates traversed by a cross. A dumb-bell form of this deposit is also sometimes seen, resembling certain forms of uric acid and the coalescing spherules of a much rarer sedi- ment— carbonate of calcium. Oxalate of calcinm is insoluble in acetic but soluble in hydro- chloric acid. The octahedra are frequently met with in the urine of persons who have partaken of garden rhnbarb ; the crystals may often be deposited artificially by dropping a fragment of oxalic acid inte several ounces of urine and setting aside for several hours (WaddLngton).
id .y Google
, Hlppurl
URINARY SEDIMENTS. 401
Carbonate of Calcium is rarely found in the urine of man, but fretjnently in that of the horse and other herbivorous animata. Humaa urine containing carbonate of calcium often reddens litmns paper; and it ia only after the removal, on standing, of the excess of carbonic acid that the salt is deposited. It consiets of minute sphe- rnles, varying in size, the smaller onw often in process of coalescence. The dumb-bell form thus produced is easily distinguished from similar groups of uric acid or oxalate of calcium by showing a blaclt cross in each spherule when viewed by polarized light. Aceticacid dis. solves carbonate of calcium, libe- rating carbonic acid gas, with visible effervescence (under the microscope) if the slide has been previously warmed and a group of crystals be attacked.
Hippuric Add. — The pointed rhombic prisma and aeicular crys- tals are characteristic, and easily recognized. The broader crystals may possibly be mistaken for triple phosphate, and the nar- rower for certain forms of uric acid; bnt insolubility in acetic
acid distinguishes them from the former, and solubility in alcohol from the latter. These tests may be applied while the deposit is under microscopic observation. An alooholie solution, of hippuric acid evaporated to dryness, and the residue treated with water, ^ives a solution from which characteristic crystalline forms of hippuric acid may be obtained on allowing a drop to dry upon a slip ot glass. The organized depoaite in urine entail greater care in their determi- nation, and usually require a higher magnifying power for their proper examination than those of crystalline form. The figures are drawn to 230 diameters. The following notes will assist the observer.
Casts of tmniferous tvhvli are fibrinous massra of various ibrras, and often of considerable length — sometimes delicate and transparent, occasionaliygranu lar, and often beset with fat globules. Epithelial d4hris are frequently present in urine in the form of nucleated cells, reguki and oval when full, but angulai and unsyrametrical when par tialiy emptied of their contents — sometimes perfect, but more frequently a good deal brokeo
up. Epltbellul CelU ai
U*
id .y Google
402 MORBID URINE.
Mood is easily recognized. Urine containing it ia high-colored, and the corpuscles appear under the microscope as reddish cironlar disks, either single or laid to- gether in strings resembling piles of coin. Their color and somewhat smaller siae serve to distingnish them from pus-cor-
Suscles. In douhtfnl cases a rop of blood from the finger shoald he dilated with water and used for comparison. After urine containing blood has stood for some time, the corpuscles lose their regular outline and become ai^nlar. (See a in the figure.) Day, of Geelong, testa for blood in urine, or in stains on clothing, by adding a few Blood iJorpuscias. drops of a recentlj^ prepared
alcoholic solution of the inner nnoxidized portions of guaiacum reain and then a small quBDtity of Bobbins' aqueous or ethereal solution of peroxide of hydrogen, when a blue color r^ults. If the stain is on a dark-colored febric, the moistened parts may be pressed with white blotting paper, when blue impressions will be obtainetL Contact with niitny substancM causes the blue reaction or oxidation of guaiacum ; the peculiarity of blood is that it does not produce this eficct unless peroxide of hydro- gen or a similar antozonic liquid is present. Bodies such as per- manganate of potassium, whose oxygen is, apparently, in the form of ozone, also gives rise to a bine color with guaiacum ; peroxide of hydrogen and other compounds wh(se oxy^n is in the opposit*, positive, or, according to SchSnbein, antagonistic condition, produce no such effect. It would seem as if blood or some other constituent of blood has the power of converting positive into negative oxygen, and thus cause an effect which negative oxygen alone is able to produce ; for of all substances which, like blood, do not alone cause guaiacum to become bine, blood is the only one that so affects anto- aonides (themselves inactive) as to enable them to act as ozonides, that is to oxidize the guaiacum. Both the venous and arterial fluid from any ted-blooded animal will produce this blue reaction. Fruit stains are darkened by ammonia, which does not alter the color of blood. Iron stains or irou-monld yield no color to water, whereas the red coloring matter of blood is soluble in water. The peroxide of hydrogen should be free from more than a trace of a«id.
Ptie and Mucus. — Purulent urine deposits, on standing, a light- colored layer, easily diffused through the liquid by shaking. Acetic acid does not dissolve the sediment ; and solution of potash, of official strength, converts it into a gelatinous mass. Under the micro- scope, pu3-corpuBoles appear rounded and colorless, rather larger than blood-disks, and somewhat granular on the surface. They generally show minute nuplei, whiph are more distinctly seep after
id .y Google
UKINABT SEDIMENTS,
treatment with aoetii, acid (See tlie portion of the figure marked a.)
Mncns possesses nr. definite mic " ' ^-"- '"-^ '-
has imbedded io it pus epithe
lium, and air-bubbtes Macus is
coagulated in a peculiar and
characteristic manner by acetic
acid; and this reaction toother
with the ropj appearand it
imparts to nrine, prevent? its
being confoanded with pii&
Day's test for pus consists in
adding a drop or two otoxid zed
tincture of guaiamm to the
nrine or other liqnid when a
clear blue color is ^rodu e]
It is necessary t« moisten dry
pus with water before applj-
mg the test. The test liquid
is made by exposing a saturated Pos CorpuscieB.
alcoholic solation of guaiacum
tc the air until it lias absorbed a sufficient quantity of oxygen to
give it the property of turning green when placed in contact with
iodide of potassium. Day's test for mnciis consists in the application,
first, of oxidiaed tincture of guaiacnm, which by itself undergoes no
change in the presence of mucus, and then in the addition of carbolic
acid or creasote, which quiokiy changes the color of the guaiacum to
a bright blue. Neither carbolic acid nor creasofe alone will render
guaiacum blue. In testing for mncus on cloths, or when it is mixed
with blood, it is
the mnCus is in a liquid state it is better to u
with alcohol.
Sa^Mio,— Saliva is an aqueous fluid containing less than 1 per cent, of solid matter, of which one-third is an albumenoid substance termed ^(i/oZiw (from rt*i5f>jw, sptltle), a body that has power of converting starch into d^trin and grape sugar. Alkaline salts, including a trace of sulphocyanide of potaasiitm, and calcareous c< pounds, are also present.
Day's test for saliva in urine, etc., is similar to that for mucus, with the esceptiou that the blue reaction produced by the oxi- dized tincture of guaiacum and alcoholic solution of carbolic acid is highly intensified by the addition of Bobbins' aqueous or ethereal solution of peroxide of hydrogen.
FaMjf matter occurs either as minute globnles partially dif- fused through the urine (as shown at o) or in more inti- mate emulsion (&& at h in the
id .y Google
404 MOHBID URINE.
figure). Whea present in larger quantity, it collects as a sort of skim on the surface after etandiug.
Spermatozoa are liable to escape notice, on account of their small size and estreme transparency. Suspected urine should te allowed to settle some hours in a conical test-rfass, and the drop at the bot- tom examined under a high power. The drawing shows their tad- pole-like appearance.
■ Sardna verdricidi is an alga of yery r though not unfrequent in the matters vomited during certain dis- ease of the stomach. The upper figures {a) are copied from Dr. Thudichum's drawing (from urine) ; the larger fronds (6) are from vomited matter.
Extraneous hodies, such as hair, wool, or fragmente 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 ad- mixtures.
EsAMINjIIION of TjEINiBY OaIOTJ!.!.
The term calculus is the diminutive of oalx, a lime- or chalk-stone.
Knowledge of the composition of a calculus or nrinary deposit affords valuable diagnostic aid to the physician ; hence the import- ance of a correct analysis of these substances.
Nature of Oaieult. — Urinary calculi have the same composition as unorganized urinary sediments. They consist, in short, of sedi- ments that have been deposited slowlv 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 lie urine has been passed — the urates less readily soluble in warm water, the calcic phosphate insoluble in acetic a^id until it has been dissolved in hydrochloric acid and reprecipitated by an alkali.
Preiiimnary 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 a ^ain of the sawdust for the analysis ; if the former, carefully scrape off portions of each layer, and examine them separately. If the calculus is in fragments, select fair specimens of about half a
id, Google
INARY CALCULI.
Analysis. — Commence the aBalyais by heating a portion about the size of a pin's head, on platinum foil, in order to ascertain whether organic matter, inorganic matter, or both, are present. If both, the ash is examined for inor- ganic substances, and a fresh portion of the calculus for uric acid by the murexid test. (In the absence of uric acid any slight charring may be considered to be due to indefi- nite animal matter.) If composed of organic matter only, the calculus will in nearly all cases be uric acid, the indi- cation being confirmed by applying the murexid teat in a watch-glass to another fragment, half the size of a small pin's head. If 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 larger than a sixpence and pre- viously moistened with water, and adding three or four drops of water one after the other as each passes through the paper. If the calculus is suspected to contain more than one substance, boil about half a grain of the powder in half a test-tubeM of distilled water for a few minutes and pour it on a small filter. Proceed according to the following Table ;—
|
ImolubU. Phosphates, oxalates of calcinm, and free uric acid. Boil with two or tliree drops of hydrochloric acid and filter. |
Soluble. Urates, These will pro- bahiy be redepoa- ited as the solu- tion cools. Small |
||
|
Insoluble. Uric acid. Apply the murexid test (p. 297). |
SoluUe. Phosphates and oxalate of oalcinm. Add excess of amiaonia, and then excess of acetic acid ; filter. |
detected by eva- porating the solu- tion to di-ynesB. They are tested for ammoniam, so- dinm, calcium, and the uric radical by |
|
|
Insoluble. Oxalate of calcium. |
Sotuile. They may he repre- cipitated by ammonia. |
the appropriate re- agents. |
id, Google
J06 MOREIT) URINE
Varieties of calcuU. — Calculi composed entirely of uric add are common ; a minnte portion iieated on platinnm foil cbars, burns, and leaves scarcely a, trace of ash. The piiosphatea frequently occur together, forming what is known as the fusible calculus, from the readiness with which a fragment aggregates, and even fuses to a bead, when heated on a loop of platinum wire iu the blowpipe-flame. The phosphates may, if necessary, he further examined bj the method described in connection with urinarj deposits. Oxalate of calcinm often occurs alone, forming a dark-colored calculus having ft very rough surface, hence termed the mulberry calcvlus. Smaller calculi of the same substance are called, from their appearance, hempseed calculi. Calculi of cystin are rarely met with. Xanihin (from |a*flof, xanthos, yellow, in allusion to the color it yields with nitric acid) still leas often occurs as a calculus. The earthy concre- tions, or chalk-stones, which frequently form in the joints of gouty persons, are composed chiefly of urates, the sodium salt being that most commonly met with. Gall-stones, or biliary calcvii, occasion- ally form in the gall-bladder: they contain cholesterin (from }^ri, chole, bile, and <itrpc6;, stereos, solid), a fatty substance of alcoholoid constitution, soluble in rectified spirit or ether, and crystallizing from such solutions in well-defined, square, scaly ciystals. Calculi of many pounds weight are often found in the stomach and larger intestines of animals.
QUESTIONS AND EXBKOISES.
864. In breathing, how much carbon (in the form of carbonic acid gas) is exhaled from the lungs every 24 hours ?
865. How may the presence of carbonic acid gas in expired air be demonstrated ?
866. Mention an experiment showing the escape of moisture from the lungs during breathing.
867. State the method of testing for albumen in urine.
868. Give the tests for sugar in urine.
869. What is the average composition of healthy urine? 810. Give the tests for urea.
871. Write the rational formulaa of some compound ureas in wliich methyl or ethyl displace hydrogen.
872. Describe an artificial process for the production of urea, giv- ing equations.
873. Sketch out a plan for the chemical examination of urinary sediments.
B74. A deposit is insoluble in the supernatant urine or in acetic acid ; of what substances may it consist !
875. Which compounds are indicated when a deposit redissolvea on warming it with the supernatant urine ?
876. Name the salts insoluble in warmed urine but dissolved on the addition of acetic acid.
877. Mention the chemical characters of cystin. At what stage of analysis would it be reoogiiiaed ?
id .y Google
GALENICAI. PREPARATIONS. 40T
|
878. Describe the microscopical appe |
arance of the foUowiog |
|
ary deposits; — |
|
|
Uric Acid. |
Tube-caats. |
|
Cjstin. |
Epithelial debris. Blood. |
|
Triple phosphalfl. |
|
|
Earthy phcffiphates. |
Pus. |
|
Urates. |
Mucus. |
|
Oxalate of Calcium. |
Fat. |
|
Carbonate of Calcium. |
Spermatozoa. |
|
Hipp uric Acid. |
Sarcina. |
|
Extraneous Bodies. |
calculi.
882. "Why is the "fusible calculus" so called, and what is its com- position !
883. Stat« the characters of " mnlberry" and " hempseed" calculi.
884. What are the " chalk-stones" of gout and " gall-stonea" or " biliary calculi V
THE GALENICAL PREPAKATIONS OF THE BKITISH PHAHMACOPtEIA.
The preparation of Confections, Decoctions, Enemas, Extracts, Giyeerines, Infusions, Inhalations, Juices, Lini- ments, Lozenges, Mixtures, Ointments, Pills, Plasters, Poultices, Powders, Spirits, Suppositories, Syrups, Tinc- tures, and Wines, includes a number of mechanical rather tban chemical operations, and belongs to the domain of pure Pharmacy. The medical or pharmaceutical popil will have had ample opportunity of practically studying these compounds before working at experimental chemistry, and will probably have prepared many of them according to the directions of the Pharmaeopoiia ; if not, he is referred to the pages of the last edition of that work for details.
Among the extracts of the British Pharmaeopoiia, how- ever, there are five (namely, those of Aconite, Belladonna, Hemlock, Henbane, and Lettuce) which are not simply evaporated infusions, decoctions, or tinctures, like most others, but are evaporated juices from which vegetable albumen, the supposed source of fermentation and decay,
id .y Google
408 OFFICIAL GALENICAL PK EPA RATI 0 N S .
has been removeiJ, and chlorophyll (the green coloring- matter of plant-juice) retained practically unimpaired in tint. In order that attention may be concentrated on the process by which these are prepared, rather than on the extracts themselves, it is advisable to make an extract of some ordinary green vegetable, such as cabbage or turnip- tops. Bruise the green leaves of a good-sized cabbage in a mortar, and press out the juice ; heat it gradually to 130°, and remove the green flocks of chlorophyll which separate, by filtration through calico. "When the liquor has all passed through the filter, set the chlorophyll aside for a time, heat the strained liquor to 200° to coagulate- albumen ; remove the latter by filtration and throw away; evaporate the filtrate by a water-bath to the consistence of thin syrup ; then add to it the chlorophyll, and, stirring the whole together assiduously, continue the evaporation at a temperature not exceeding 140°, until the extract is of a suitable consistence for forming pills. A higher tem- perature than that indicated would cause the alteration of the chlorophyll to a dark-brown substance, the extract no longer having the green tint wliich custom and the British Fharmacopceia demand.
QUESTIONS AND EXERCISES.
885. Enumerate the different classes of official galenical prepara-
886. Describe the genera! process for the preparation of green extracts : —
Aconite. Hemlock,
Belladonna. Henbane.
Lettuce.
887. Why is vegetable albumen exclndcd in th.e preparation of green extracts !
888. How may chlorophyll be removed from vegetable juices, and again be introduced into their evaporated residues, without destroy- ing its color.
889. For wiiat reason is espoaure of chloropliyll to heat avoided in the manufacture of green extracts ?
id .y Google
CIAL CUEMICAL rHErARATiONS
THE CHEMICAL PREPARATIONS OF THE PHAKMACOPfEIAS.
The process by which every official chemical substance is prepared has already been described, and the strict chemical chai-acter of the processes iJiastrated 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 manufacture of chemical substances depends, he is advised to prepare, if he has not done so already, a few ounces of each of the salts mentioned in the Pharmacopeias or commonly used in Pharmacy. An additional guide in these operations will be the Pharmacopceia itself.
The production of many chemical and galenical sub- stances on a commercial scale can only be successfully car- ried on in manufacturing-laboratories and with some linow- ledge of the circumstances of supply and demand, value of raw material, and of by-products. Commercial Chem- istry and Pharmacy, however, can best hope for success when founded on the working out of abstract principles. The problem of manufacturing-success is solved with cer- tainty by wisely applied S' '
Memorandiinh. — The next subjects of experimental study will be determined by the nature of the student's future pursuits. In most cases the operations of quantitative analysis will engage attention. These sliould be of a volu- metric and gravimetric character ; for details concerning them see the following pages.
QUANTITATIVE ANALYSIS. INTRODUCTORY REMARKS.
General principles. — The proportions in which chemical substances unite with each otlier in forming compounds are definite and invari- able (page 36). Quantitative analysis is based on this law. When, for example, aqueous solutions of a salt of silver and a chloride ai'e mized, a white card; precipitate is prodaced containing chlorine and
id .y Google
410 QUANTITATIVE ANAIYSIS.
silver in atomic proportions, that ia, 35.5 parte of cbloride to 108 of silver. No matter what the chloride or what the salt of silver, the resulting chloride of silver ia invariable in composition. The formula AgCl is a convenient picture of this componnd in these proportions. The weight of a definite componnd being given, therefore, the pro- portional amonnta of ita constituents can be ascertained by simple calculation. Thus, for instance, 8.53 parts of chloride of silver ooft- tain 2.11 paiffi of chlorine and 6.42 of silver ; for if 143.3 (the molec- ular weight) of chloride of silver contain 35.5 (the atomic weight) of chlorine, 8.53 of chloride of silver will be found to contain 2.11 of chloriae : —
143.5 : 35.5 :: 8.53 : x
1.4ii5 X = 2.11.
And if 14.^.5 of chloride of silver contain 108 of silver. 8.53 of chlo- ride of silver will contain 6.42 of silver. To ascertain, for example, the amount of silver in a substance, containing, say, nitrate of silver, all that is necessary is to take a weighed quantity of the substance, dissolve it, precipitate the whole of the silver by adding hydrochloric acid or other chloride till no more chloride of silver falls, collect the precipitate on a filter, wash, dry, and weigh. The amount of silver in the dried chloride, ascertained by calculation, is the amount of silver in the quantity of substance on which the operation was con- ducted; a rule-of-three sum gives the quantity per cent. — the form in which the resnlts of quantitative analysis are usually stated. Occasionally a constituent of a substance admits of being isolated and weighed in the nucombiued state. Thus the amount of mercury in a Bubstanoe may be determined by separating and weighing the mercury in the metallic condition; if occurring as calomel (HgOl) or corrosive sublimate (HgOlA the proportion of chlorine may then be ascertained by calculation (Hg^200 ; Cl=^35.5).
Natiire ofuravimetric Quaittitative Analysis. — As above stated, a body may be isolated and weighed and ite quantity thus ascertained ; or it may be separated and weighed in combination with another body whose combining proportion is well known ; this is quantitative andyais by the gravimetnc method.
Nature of Volumetric Qaaniitattve Anoiysis. — Quantitative an- alysis by'the volumetric method consists in noting the volume of a liquid required to be added to the aubataace under examination before a given effect ia produced. Thus, for instance, a solution of nitrate of Eilrcr of known strength may be used in experimentally ascertain-
ed .yCoOglc
MEASUREMENT Or ATMOSPHERIC PRESSURE. 411
iiig an unknown amount Of eliloride in any substance. The silver Bolution ia added to a solntion of a definite q^uaatity of the substance until fioclcs of chloride of silver cease to be predpitatecl : every 108
Sm-ta of silver added (or 170 of nitrate of silver : Ag=108, N=14, '3=48 ; total 170) incKcates the preaence of 35.5 of chlorine, or an equivalent quantity of any ohloriae. The preparation of standard solutions, such as tliat of nitrate of silver, to which allusion is here made, requires considerable care ; but when made, certain analyses can be eiecuted with far more rapidity and ease than by gravimetric
Note. — The quantitative analysis of solids and liquids often in- volves determinations of t«mpecature and specific gravity. These processes will now be explained, after which an outline of volumetric and gravimetric quantitative analysis will be given. The scope of this work precludes any attempt to describe all the little mechanical details obMrved by quantitative analysts; essential operations, how- ever, are so fnlly toeated that expert manipulators will meet with little difficulty.
Measurement of Atmospheric Pressure.
The Barometer. — The analysis of gases and vapors involves, also, determinations of the varying pressure of the atmosphere aa indi- cated by the ba-rometer (from 0apos, baros, weight, and iiiirpou, jJie- iron, measure). The ordinary mercurial barometer is a glass tube 33 or 34 inches long, closed at one end, filled with mercury, and inverted in a smaU cistern or cup of mercury. The mercury remains iu the tube owing to the weight or pressure of the atmosphere on the exposed surfcce of th? liquid, the average height of the column being nearly 30 inches. In tiie popular form of the instrument, the wheel-barometer, the cistern is formed by a recurvature of the tube ; on the exposed surface of the mercury a float is placed, from which a thread passes over a pulley and moves an index whenever the column of mercury rises or falls. As supplied to the public these barometers are usually inclosed in ornamental frames with thermome- ters attached. In the wheel-barometer the glass tube and contained column of mercury are altogether inclosed, the index alone being visible. In &e otner variety the upper end of tlie glass tube and mercurial column are exposed and the height of the mercury is ascer- tained by direct observation.
Tlie aneroid barometer (from a, a, without, and i-jjpif, neroa, fluid) consists of a smalt, shallow, vacuous metal drum, the sides of which approach each other when an increase of atmospheric pressm-e occurs, their elasticity enabling them to recede towai-d their former position on a decrease of pressure. This motion is so multiplied and altered in direction by levers, etc., as to act on a hand traversing a plate on which is marked numbers corresponding with those showing the height of the mercurial column of the ordmaiy barometer by which the aneroid was adjusted. The Bourdon haromUer (from the name of the inventor) is a modified aneroid containing in the place of the round metal box, a flattened vacuous tube of metal, bent nearly to
id .y Google
412 QUANTITATIVE ANALYSIS.
a circle. These barometers are also useful for measuring the prea- Bure in steam-boilers , etc. Under the name of pressure-gauges tiey are sold to indicate pressures of 500 pounds aad upwards per square inch. Prom their portability (they can be made of 1 to 2 inches in diameter and 1 inch thick) tiey are excelleat companions for trav- ellers wishing to know the heights of hills, mountains, and other elevations.
For further information concerning the influence of pressure on the volume of a gas or vapor see page 430; and for descriptions of the methods of analyzing gaaes, refer to Gauot's "Physics" (trans- lated by Atkinson), Miller's "Chemical Physics," and "Analysis of Gases" in Watts's " Dictionary of Chemistry."
MEASUEEMEITT OF TEMPERATUIIE.
General Principles. — As a rule, all bodies e\pand on the addi- tion, and contract on the abstraction of heat the ilteration in volume being constant and regular for equal increments oi decre- ments nf temperature. The estent of this alteiafiou m a given sub- stance, 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 mer- cury, the chief advantages of which are that it will bear a high tem- perature 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 inclosed, and, from its ^od conducting power for heat, responds rapidly to changes of temperature. Plati- num, earthenwai'e, alcohol, and air are also occasionally used for thermometric purposes.
The Thermometer. — The construction of an accurate thermometer is a matter of great difficulty ; but the fol- lowing are the leatSing steps in the operation. Select a piece of glass tubing having a flue capillary {Gapilltis, a hair) bore, and about a foot long ; heat one extremity in the blowpipe-flame until the oriflpe closes, and the glass is sufficiently soft to admit of a iDulb being blown ; heat the bulb to expel air, immediately plunging the open ex- tremity of the tube into mercury; the bulb having cooled, and some mercury having entered and taicen the place of expelled air, again heat the bulb and tube until the mer- cury boils and its vapor escapes through the bore of the tube; again plunge the extremity under mercury, which ■wiU probably now completely fill the bulb and tube. When cold the bulb is placed in melting ice. The top of the column of mercury in the capillary tube should then he within an inch or two of the bulb ; if higher, some of the
id .y Google
THERMOMETRIO SCALES. 413
mercury must be expelled by heat; if lower, more metal must be introduced as before. The tube is now heated near the open end and a portion drawn out, until the diameter is reduced to about one-tenth. The bulb is next ■warmed until the mercurial column rises above the con- stricted 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 boiling-water (a medium having, ceteris pari- bus, an Invariable temperature), and, when the position of the top of the mercurial column is constant, a mark is made on the tube by a scratching diamond or a file. This operation is repeated with melting ice (aiso a medium having an invariable temperature). The space between these two marks is divided into a certain number of inter- vals termed degrees. Unfortunately this number is not uniform in all countries ; in England it is 180, as proposed by Fahrenheit ; in Prance 100, as proposed by Celsius (the Centigrade scale), a number generally adopted by sci- entific men ; in some parts of the Continent the divisions are 80 for the same interval, as sn^ested by Reaumur. 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.
Thermometric Scales. — On the Centigrade abd Reaumur scales the fteeaing'-poiiit of water is made zero, and the boiling-point lOO and 80 respectively; on the Pairenheit scale the aero is placed 32 degrees below the coagealicg-point of water, the boiling-point of which becomes, conseqnently, 212. Even on the Fahrenheit system temperatares below the freeaing-point of water are often spoken of as "degrees of frost;" thus 19° degrees as marked on the tliermom- eter would be regarded as "13 degrees of frosts" It is to be regret- ted that the freezing-point of water ia not universally regarded as the zero-point, and the namber of intervals between that and the boiling-point everywhere the same.
The degrees of one scale are easUy converted into those of another, if their relations be remembered, namely: — 180 (F.), 100 (0.), 80 (R.) ; or IS, 10, and 8; or, best, 9, 5, and 4.
Formul(e for the conversion of degrees of one tkermometrie scale into those of another.
F=FalireiiIiell. O-Cenlistsde.
S==H6Bnmar. l>=Tha obserTcd dagree.
If above the freezing-point of water {32° F ; 0^ C ; 0° E),
FintoC (D— 32)-i-9xS.
F '■ R (D— 32).4-9x4.
U " F D-^ 5 X 9-1-32.
E " F D-^ 4 x9-i-32.
36*
id .y Google
414 QUANTITATIVE ANALYSIS.
If below freezing, but above 0° F (—170.77 0 ; — 14<=.32 E),
FintoO — (32— D)-^9X5.
F '■ E . . . . . .— (32— Di-i-9x4.
0 " P 32— (D-I-5X9);
E " F 32— (D-S.4X9).
If below oo F (_no.77 o ; —140,22 B),
FintoC — (D+32)-i.9 x5.
F " E — (D+32)-^9 X4.
0 " P — D-^ 5 xa)- 32.
R " F .— (D-5- 4 X 9)— 32.
For all degrees :—
OintoR D-;-5x4
E " 0 D-H4X5.
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 is inserted in the liquid, if a pure subetaiice. In taking the boiling- point of a liquid which ia being distilled from a mixture, the bulb of the thermometer should be near to, but not beneath the surface.
The following are the boiling points of a few substances met with in pharmacy : —
Ceuligrnde. - Fahrenheit.
Alcohol, absolute 18,3 173
■' 84 per cent 79.5 175
" 49 per cent, (proof spirit) . , 81,4 178.5
aniylic 132.2 270
Benzol 80.6 177
Bromine 47.2 117
Benzoic acid 239.0 462
Carbolic acid 187.8 370
Chloroform Gl 142
Ether (B. P.) (below) 40.5 105
" pure 35 9.'>
Mercnry in vacuo (as in a therniometer} 304 580
" in air (barom, at 30 inches) . . 350 662
"Water {barom. at 29.92 incliea) ... 100 212
" { " 29.33 " ) . . . 99.5 2H
" ( " 28.T4 " ) . . . 99 210
Saturated Bolntions of :—
Cream of tartHT 101 214
Common salt 106,6 224
Sal-ammoniac 113.3 2.16
Nitrate of Bodinm 119 24B
Acetate of sodinm 124.4 256
Chloride of calcium L79,4 355
id .y Google
PYROMETEItS. 415
To determine inelting-points of fats, — Heat a fragment of the substance (spermaceti or wax for example) till it liijuefles, aad then draw up a aiiiaU portion into a thin glass tube, about the size of a knitting-needle. Immevse the tube in cold water contained in a beaker, and slowly heat the vessel till the thin opaque cylinder of solid fat melts and becomes transparent: a delicate thermometer placed in the water indicates the point of change to the fifth of a degree. Remove the source of heat, and note the congeal ing-point of the substance ; it wOl be identical with or close to the melting-point.
Pyrometers. — Temperatures above the boiling-point of mercury are determined by ascertaining to what extent a bar of platinum or porcelain has elongated. The bar is inclosed in a cavity of a suitable case, a plug of platinum or porcelain placed at one end of the bar, and the whole exposed in the region whose temperature is to be found. After cooling, the distance to which the bar has forced the plug along the cavity is accurately measured and the cor- responding degree of temperature noted. The value of the distance is fixed for low temperatures by comparison ■with a mercurial thermometer, and the scale carried up- wards through intervals of equivalent length. Such ther- mometers are conventionally distinguished from ordinary instruments by the name pyrometer (from wiip, pur, fire, and iiitfov, melron, measure).
The following meliing-poinls of official s given in the British Pharmacopteia : —
In aegrees In dug
Acetic acid, g-lacial .... 8.9 4t
" " congeals at 1.1 3^
Benzoic acid 120 34t
Carbolic acid 35 9£
Oil of tlieobroma 50 12S
PhoBphoras 43.3 IIC
Prepared lard . . . (about) 38 IOC
Buet 39.5 lOi
Spevmaeeti 38 10(
Wliite wax . . (not under) 6!i.5 15(
Yellow wax 60 14(
The order of fusibility of a few of the metals lows: —
id .y Google
|
QUANTITAT |
IVE ANALYS |
IS. |
|
Mrrcuiy |
- 39.4 |
— 39 |
|
Poti& mm |
+ 62.5 |
+144.5 |
|
Sodium |
97.6 |
207.7 |
|
Tin |
227.8 |
442 |
|
Bi^mntt |
264 |
607 |
|
Lead |
d25 |
617 |
|
Zmu |
411.6 |
773 |
|
Antimu.j |
b21 |
1130 |
|
'.live. |
loaa |
1873 |
|
Copppr |
1001 |
1996 |
|
Gold |
1102 |
2016 |
|
Cast iron |
IV60 |
2786 |
QUESTIONS AND EXERCISES. 890. On what fundamental laws ore the operations of quintitiiive
891. What is the general nature of gravimetric quantitative analysis ?
892. Describe the general principle of volumetrie quantitative analysis t
893. How are variations in atmospheric pressure quantitativi,ly determined?
894. Explain the coDStmctioa and mode of action of a meicnual barometer.
895. In what respect does a wheel-barometer differ from an instru- ment in which the readings are taken from the top of the column of mercury!
896. On what general principles are thermometers consti-noted?
897. What material is employed in making thermometers?
898. Why is mercury selected as a thermometric indicator ?
899. Describe the manufacture of a mercurial thermometer.
900. How are thermometers gi'aduated?
901. Gfive formnlte for the conversion of the degrees of one ther- mometric scale into those of another, (a) when the temperature is above the fceezing^point of water, (&) below 32^ p. but above fP P., and (c) below 0° P.
902. Name the degree C. equivalent to 60° P.
903. What degree 0. is represented by —4° F. !
904. Mention the degree P. indicated by 20° 0.
905. Convert 100<= E. into degrees 0. and P.
906. State the boiling-points of alcohol, chloroform, ethor, mer- cury, and water on either thermometric scale.
907. Describe the details of manipulation in estimating the melt- ing-point of fats.
908. In What respect do pyrometers differ from thermometers ?
909. Mention the melting-points of glacial acetic acid, oil of thco- broma, lard, suet, and wax.
910. Give the fusing-pointa of tin, lead, zinc, copper, and cast-
id .yCoOglc
ESTIMATION OF WEH
ESTIMATIOH OF WEIGHT.
All bodies, celestial and terrestrial, attract eacli other, the amount of attraction being in direct proportion to the quantity of niatt«r of which they consist, and in inverse proportion to the squares of their distances. ' This is gravitation. When gravitation in certain direc- tions is exactly counterbalanced by gravitetion in opposite directions, a body \e. g. the earth) remains suspended in space. Sneh a body, in relation to other bodies, has gravity bat not weight. Weight is the effect of gravity, being the excess of gravitation in one direction over and above that exerted in the opposite direction. Weight, truly, in any terrestrial substance, is the excess of attraction which it and the earth have for each other over and above the attraction of each in opposite directions by the various heavenly bodies. Bat, practically, the weight of any terrestrial substance is the effect of the attraction of the earth only. Specific weight is the definite or precise weight of a body in relation to its balk ; it is more usually but not quite correctly termed specific gravity — gravity belonging to the earth, not to the substance.
QUESTIONS. 911. What is understood by gravitation ? 012. State the difference between weight and gravity.
913. Mention a case in which a body has gravity but no apparent n-eight.
914. Practically, what causes the weight of terrestrial
Weights abd Mbasobes.
The Balance. — The balance used in the quantitative analytical chemistry must be accurate and sensitive. The points of suspension of the beam and pans should be polished steel or agate knife-edges, working on agate planes. It should turn easily and quickly, without too much oscillation, tfl ;jo or gjj of a grain, or 3V of a milligramme, when 1000 grains, or 50 or 60 grammes, are placed in each scale. (Grammes are weights of the metric system, a description of which is given on the next two or three pages.) The beam ^ould be light but strong, capable of supporting a load of 1500 grains or 100 grammes ; its osciUations are observed by help of a long index attached to its centre, and continued downwards for some distance in front of the supporting pillar of the balance. The instrument should be provided with screws for pnrposes of adjust- ment, a mechanical contrivance for supporting tiie l>eam above its bearings when not in use or duiing the removal or addition of weights, spirit levels to enable the operator to give it a horizontal position, and be inclosed in a glass case to protect from dust. It should be placed in a room the atmosphere of which is not liable to be con- taminated by acid fnmes, in a situation free from vibration; and a
id .y Google
418 QUANTITATIVE ANALYSIS.
vessel containing' lumps of quicklime should be placed in the case to keep the inclosed air dry and prevent the formation of rust on the steel knife-edges or other parts. During weighing, the doors of the balance should be shut, in order tliat currents of air may not un- equally iniluenee the pans.
The Weights. — These should be preserved in a box having a sepa- rate compartment for each. They must not be lifted directly with the fingers, but by a small pair of forceps. If grain-weights, they should range from 1000 gr. to -^ gr., a A weight being fashioned of gold wire to act as a "rider" on the divided beam, and thus indicate by its position lOOths and lOOOths of a grain. From -fy, to 10 grs. the weights may be of platinum ; thence upwards to 1000 grs. of brass. The relation of the weights to each other should be decimal. Metric decimal weights may range from 100 grammes to 1 gramme, of brass, and thence downwards to 1 centigramme, of platinum, a gold centigramme rider being employed to indicate milligrammes aud tenths of a milligramme.
The Metric System of weights (the word metric is Irom the Greek (ji^poii, laetron, measure) is greatly to be preferred to all others, the relation of the metric weights of all denominations to measures of length, capacity, and surface being so simple as to be within the per- fect comprehension of a child ; while under the British and American plans, the weights have no snch relation, either with each other or with the various measures. Moreover the metric system is in perfect harmony with the universal method of counting ; it is a decimal sys-
[It is perhaps impossible to realize, much more express, the ad- vantages we enjoy from the fact that in every country of the world the system of numeration is identical. That system is the decimal. Whatever language a man speaks, his method of numbering is deci- mal ; his talk concerning number is decimal ; his written or printed signs signifying number are decimal. "With the figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 he represents all possible variation in number, the posi- tion of a figure in reference to its companions aloae determining its value, a figure on the left hand of any other figure in an allocation of numeral symbols (for example, 1811) having ten times the value of liat figure, while the figure on the right hand of any other has a tenth of the value of that other. When the youngest pupil is asked how many units there are in 1871, he smiles at the simplicity of the question, and says 1871. How many tens? 187, and 1 over. How many hundreds ? 18, and "il over. How many thousands ? 1, and 871 over. But if he is asked how many scruples there are in 1871 grains, how many drachms, how many ounces — he first inquires which drachms or whicn ounces are meant, avoirdupois ounces, troy ounces or wine ounces, and then brings out his siate and pencil. And so with the pints or gallons in 1871 fluidonnces, or the feet and ^ards in 1871 inches, or tiie pence, shillings, and pounds in 1871 farthings ; to say nothing of cross questions, such as the value of 1871 article at 2 dollars and 20 cents per dozen, or of the perplexity catised by the varying values of several individual weights or of measures of length, capacity, and surface in different parts of the country. What is desired is, that there should be an equally simple decimal relation
id .y Google
WEIGHTS AND MEASURES. 419
amocg meiglits and measures and coins as already Tiuivcrsaily exists among numbBrs. This condition of things having already been in- troduced into moat other countries, there is no good reason whj' it Bhonld not be accomplished in the United States and Great Britain.] The Metric System of weights and measures is founded on the metre. The engraving represents the tenth part of a metre, divided into 10 centimetres, and each centimetre into 10 millimotr.es.
rfiiiM imiiiiniLiiJiiii iiniiiiimiiiiipMlimpjiuimiMmmitiii
^
Length. — The Unit of Length is the Metre, derived from the measurement of the Quadrant of a Meridian of the Earth. (Prac- tically it is the length of certain carefally preserved bars of metal, from which copies have been taten.)
Surface. — The Uhif^ of Surface is the Abb, which is the Square of Ten Metrra,
Oapacity. — The Unit^ of Gapacity is the Litre, which is the Cube of a Tenth Part of a Metre.
Weight. — The Unit of Weight is the Gram, which is the Weight of that quantity of distilled water, at its raaxiniuni density, which fills a Onbe of the One-hundredth part of the Metre.
Note. — Multiples are denoted by the Greek words " Deka," " Ten," " Heeto," Hundred, " Kilo," Thousand. SubdiTisions, by the Latin words, "Deoi," One-tenth, "Centi," One-liundtedtli, "Milli," One-thousandth,
cm M titles. LcngUi, Surface. Capacity. Weight.
1000 Kilo-metro , . Eilo-litre Kilo-gram
100 Hecto-metre Kcctare Hecto-litre Hecto-gram
10 Delta-metre . . . Deka-litre Deka-gram
1 (Units) METRE ABID " LITBE OBAM
■1 Deci-metre . . . Deci-litre Deci-gram
.01 Centi-metre Centiare Ceuti-litre Centi-gram
.001 Millt-metre . , , Milli-litre Milligram
When the metric method is exclusivelvadopted these Units and Table, comprising the entire System of Weights and Measures, re- present all that will be essential to be learned in lieu of the numerous and complicated Tables hitherto in use. Adopting the style of ele- mentary books on Arithmetic, the Table may be expanded in the following manner : —
id .y Google
420 QUANTITATIVE ANALYSIS.
10 Milligrams make I cpntigrim 10 Oeatigrams " 1 decigram 10 Decigrams " 1 grim 10 Grams " 1 dekagram
10 Dekagrams " 1 hectogram 10 Hectograms " 1 kilogrtun 10 Millilitres make 1 nentditie,
10 Millimetres make 1 centimctie
Tlio following approximate equivalents of mefiiLil units should be committed to memory : —
1 Metre = 3 feet 3 inches and 3 eif^hths. 1 Are = a square whose side is li yards.
1 Litre = If pint 1 Gramme = 15^ grains. The Metric Ton of 1000 Kilo-gi-ammes = 19 cwt 2 qrs. 20 lbs. 10 oza. The Kilo-gramme = 2 lbs. 3^ ozs. nearly. The Hect-are = 2J acres nearly. For esMsci eqaivalenta, in many forms, see pages 420 an5 421, (The word gramme is, in English, usually written gram.]
The General Council nnder whose authority the British Pharma cop»Bia is issued encourages medical practitioners and pharmacists ii the adoption of the metric system, and gives the annexed statement of metric weights and n?
(From the British Fharmacopceia, of 1867.)
|
1 Milh^iamme |
= the thousandth part of one grvn. or 0.001 grm. |
|
J Centigramme |
= Ihehundi'cdth " 0.01 " |
|
1 Deoignmme |
= the tenth " 0.1 |
|
1 Gramme |
s= weight of a mbic centimetre of |
|
water at 4° 0 1.0 |
|
|
1 Decagramme |
= one bundled gi immes 100.0 |
|
I Hectogramme |
|
|
1 Kilogramme |
= one thousand giammes 1000,0 (1 kilo.). |
|
11BA8TIRB3 OP CAPACITY. |
|
|
1 Millihtre = |
1 cnb centim or tlio mea. of 1 gram, of water. |
|
1 Centilitre = |
10 ' " 10 " |
|
IDctilitre = |
. 100 ' " 100 " |
|
1 Litie |
1000 " " 1000 " (Ikilo.). |
id, Google
1 Millimetre = the thousandth pait of one metre or 0.001 metre, 1 Oentimetre = the hundredth " 0.01 metre.
1 Decimetre = the tenth " 0.1 "
I Metre = the ten millionth part of a quarter of the meridian
of the earth
1 Ounce 1 Pound
1 Fluidra*hm 1 FlnidouQoe 1 Pint 1 Gallon
1 inch = £
8 fiuidraclinis. 20 giiidounces. 8 pints.
>nds-peii(!ulniii.
13 " = 1 foot 36 " == 3 feet = 1 yard. Length of pendulum vibrating seconds of r time in the latitude of London, in a vacau the level of the sea.
1.25 pound 01 10 pounds or
(1 cubic inch of distilled water at 62° F. and 30 inch Ban grains.)
1 Minim ia i\xt 1 Fluidrachm 1 Pluidounce 1 Pint 1 Gallon
39.13i)3 jnchos. :252.458
0,91 grain of water, 5i.68 grains of wafer. 437.5 8T50,0 70,000,0 '■
id .y Google
QUANTITATIVE AN
S%
|
It II B 11 |
0.0000006 0.0000062 0.0000621 O.0006314 0.0062138 0.0621382 0.6213824 6.2138344 |
|
11 |
0.0005468 0.0054682 0.0546816 0.5468165 5.4681655 54.6816550 546.8165500 5468.1655000 |
|
1- 11 |
0.0010936 0.0109363 0.1093633 1.0936331 10.9363310 109.3633100 1093.6331000 10936.3310000 |
|
1^ |
0.003281 0,032809 0.338090 3.280899 32.808992 328.089920 3280.899200 32808.992000 |
|
0.03937 0.39371 3.93708 39.37079 393.70790 3937.07900 39370.79000 393707.90000 |
|
|
Millimetre Centimetre Decimetre Hetre Decametre Heotometi-e Kilometre . ■ . . . Myriometre |
|
1 |
ill |
|
11 |
|
|
11 •a? 12 |
ill III |
|
n a a 11 |
III ^11 |
|
£ 1 r |
|
|
. 1 ill- ill HI |
Hoa,d, Google
■WEIQHTS AND MEASUEES.
|
0.0000375 O.OO02751 0.0027512 O.0275121 0.2751208 2.7512085 27.5130846 275.1208459 |
|
|
0.0002201 0.0022010 0.0220097 O.22O0967 2.2009668 22.0096677 220.0966767 2200.9667675 |
|
|
11 |
0.00176 0.01761 1.76077 17.60773 176.07734 1760.77341 17607.73414 |
|
LI Ii |
0.000035 0.000353 0.003532 0.035317 0.353166 3.531658 35.316581 353.165807 |
|
1 .2 |
0.06103 0.61027 6.10271 61.02705 610.27052 6103.70515 61027.05152 610270.51519 |
|
Millilitre, or cable centimetre Ceutilitre, or 10 cubic centimetres Decilitre, or 100 cubic centimetres Litre, or cubic decimetre . Decalitre, or centistere Hectolitre, or decistere Kilolitre, or stere, or cubic metre Myriolitre, or decaatere |
|
II ^ |
s |
||
|
o |
|||
|
J: |
|||
|
II o |
g55§22g§ |
||
|
^s |
0? |
||
|
S |
|||
|
s s |
|||
|
Sa |
|||
|
ooSaiioSgH" |
t |
||
|
■§ |
|||
|
Ii |
|||
|
ddoooddd |
|||
|
a II |
J, |
||
|
11. |
i |
||
|
oooooe^MO |
|||
|
g- |
ddddddcJ« |
11 |
|
|
^ |
0 B |
" |
1 |
|
"i |
ja |
||
|
s.S |
m§l3SSi2SE |
||
|
1 |
la |
'-' |
|
|
^s |
|||
|
" |
|S |
ddddoMffjrJ |
1 |
|
o 11 |
d |
||
|
s |
^ |
||
|
3 |
|||
|
mcqmio^™^'^ |
|||
|
1 |
t |
isii^w^ii |
::1 |
|
odrH^^-WMMM |
|||
|
^ |
t |
aissgs |
11 |
|
lis liii |
s t 1 i 11 |
||
|
1 |
Hoa,d, Google
NTITATIVB ANALY9II
QUESTIONS AND EXERCISES.
915. Mention some advantages of a decimal system of weiglits and measures.
916. What is tho name of the chief unit of the metric decimal system of weights and measures !
917. Mention the names of the metric units of snrftice, capacity, and wei^t, and state how they are derived from the unit of length,
918. How are multiples of metno iinits indicated ?
919. State the designations of submultiples of metric units.
920. How many metres are there in a kilometre 3
921. How many millimetres in a metre !
922. How many grams in 5 kilograms ?
923. How many milligrams in 13^ grams?
924. In 1869 centigrams how many grams?
925. In a metre measure 5 centimetres wide and 1 centimetre thick how many cubic centimetres ?
926. How many litres are contained in a cubic metre of any liquid ?
927. State the British equivalent of the metre.
928. How many square yards in an are ?
929. How many fluidoancea in a litre 1
930. How many ounces in a kilogram !
931. Give the relation of a metric ton {1000 kilos.) to a British
932. How many grains are there in 1 ton t
933. How many ounces in 1 ton ?
934. How many grains of water in 1 fluidrachm ?
935. How many minims in 1 pmt?
936. How many grains in 1 pint of wa1«r 7
937. Whence is the British unit of length deiived ?
Specific Weight or Specific Oxavity,
The specific weight of a substance is its weight in comparison ■with weights of similar bnlks of other substances. This compara- tive heaviness of solids and liquids is conventionally expressed in relation to water: Qxej are considered as much lighter or heavier than water. Thus, water being regarded as unity=l, the relative weight, or specific weight, of ether is represented by the figures .720 (it is nearly three-fourths, .750, the weight of water), oil of vitriol by 1.843 (it is nearly twice, 3.000, as heavy as water). The
specific weight of substances is, moreover, the weight of similar volumes o( siidy t(egi'eea(60''P.) ; for the weight of a definite volume of any substance will vary according to temperature, becoming heavier when cooled and lighter when heated, different bodies (gases excepted) ditfermg in their rate of contraction and expansion. "While then specific weight or conventionally specijic gravity is truly the comparative weight of equal bulks, the numbers which in Great Britain commonly represent specific gravities, are the com-
id.y Google
SPEOIPIO GRAVITY. 425
parative weights of equal imlks at bif F., water being taken as unity.* 'J'lie standard ot Lompaiisoa foi gasea was formerly air, but is now HHually hydrogen
Specific Gkavity op Liquids.
Procure any small bottle holding from 100 to 1000 grains, and having a narrow neck ; counterpoise it in a delicate balance ; fill it to about halfway up the neck with pure distilled water having a temperature of 60° F. ; ascertain the weight of the water, and, for convenience, add or subtract a drop or two, so that the weight shall be & round number of grains ; mark the neck by a diamond or file-point at the part cut by the lower edge of the curved surface of the water. Consecutively fill up the bottle to the neck-mark with several other liquids, cooled or warmed to 60° F., first rinsing out the bottle once or twice with a small quantity of each liquid, and note the weights ; the respective figures will represent the relative weights of equal bulks of the liquids. If the capacity of the bottle is 10, 100, or 1000 grains, the resulting weights will, with- out calculation, show the specific gravities of the liquids ; if any other number, a rule-of-three sum must be worked out to ascertain the weight of the liquids as compared with 1 (or 1.000) of water. Bottles conveniently adjusted to contain 350, 500, or 1000 grains, or 100 or 50 grammes of water, when filled to the top of their perforated stopper, and other forms of the instrument, are sold by all chemical apparatus makers.
The following are the stated specific gravities of official liquids : —
Acid, acetic,- B.P 1.044
" U. S P 1.04T
" dfiuted, B. P. and IT. S. P 1.006
glacial 1.065 to 1.066
carbolic 1.065
hydriodic, diluted 1.112
* The trae weight of the body is its weight in air plus the weight of an equal bulk of air antl minna the weiglit of a bulk of air equal tt) the bulk of brass or other weights employed ; or, in other words, its weight in vacuo uninfluenoed by the buoyancy of the air ; but such a correction of the weight o( a body is seldom ueoassary or, indeed, desirable. Density is sometimes improperly regarded as synonymoua with ipecijic gravity. It is true that the density of a body is In exact proportion to its specific gravity ; but the former is wore correctly the ooraparstive bulk of equal weights, while speoiflo gravity is the Dum- parative weight of equal bulks.
id .y Google
6 QUANTITATIVE ANALYSIS.
Acid, hydrocUoric, B, P. and U. S. F 1.160
diluted, B. P 1.052
" " U. 8. P 1.038
hydrocyanic, B. P. and U. S. P 0.997
lactic, U. 8. P 1.312
nitric, B. P. and U. 8. P 1.420
" diluted, B. P 1.101
U. 8. P 1.068
nitro-lwdcoohloric 1.074
phosphoric diiuted, B. P 1.080
" " U. S. P 1.056
sulphuric, B. P. and U. 8. P 1.843
" aromatic 0.927
■' diluted, B. F 1.094
U. S. P 1.082
Bulphurous, solution of, B. P 1.040
U. 8. P 1.035
Alcohol, TJ. S. P 0.835
absolute 0.795
(rectifled spirit, 84 per cent.} 0.838
(proof spirit, 49 per cent.) 0.920
dilDtnm, U. S. P 0.941
fortius, U. 8. P. 0.817
amylic, B. P. and U. 8. P 0.818
Ammonia, aromatic spirit of, B. P 0.870
stronger water of, U. S. P O.90O
solution of, B. P 0.959
strong solutioa of, B . P 0.891
Antimony, solution of chloride of, B. P 1,470
Arsenic, hydrochloric solution of, B. P 1.009
Arsenical solution (Liquor Arsenicalii), B. P. , 1.009
Benaol, B. P 0.850
Bismuth and ammonia, solution of citrate of, B. P, 1.122
Bromine 2.B66
Chlorine solution of, B. P 1,003
Chloroform, B. P. and U. S. P 1.490
spirit of, B. P 0.871
Cinchona, liquid extract of yellow, B. P. (about) . 1.100
Creasote, XT. S. P 1.046
1.071
Ether, B. F 0.735
'■ U.S. P 0.750
" pure, B. P 0.720
" Tortior, U- 8. P 0.738
Glycerine, B. P. ftcd U. S. F 1.250
Iron, solution of pernitrate of, B. P 1.107
" " " " " U. S, P 1.065
" " " persulphate o^ B. P 1.441
" TJ. S. P. ... 1.330
I' strong solution of perchloride of, B. P, . , , 1,338
" tincture of perchloride of, B, P. and U. S, P, , 0,993
id .y Google
SPECIFIC GRAVITY. 42T
liQod, aolutiou of subacetal* of, B. P 1.2G0
" " » " U. S. P. ... 1.267
Lime, sacctarated aolation of, B. P 1.052
" solution of clilotiaated, B. P 1.035
Mercury (at OO 0.=32O F.) 33.596
" (atl5O.55 0.=6(PP.) 13.560
" acid solution of nitrate of 2.246
" ■' '■ ■' " " U. 8. P. . . . 2.165
Nitre. STveet spirit of 0.845
" " U. S. P 0.831
Oil of mustard, B. P 1.015
Potagh, solution of, B. P 1.058
" U. S. P 1.065
Soda, " " B. P 1.047
" U". 8. F i.071
" " chlorinated, B. P 1.103
" " " " TJ. 8. P 1.045
Sqaill, oxyracl of, B. P 1.320
Syrup, B. P 1.330
" U. 8. P 1.317
■' of buckthorn, B. F 1.320
" of ginger, B. P
" of hemideamns, B. P 1.335
" of iodide of iron, B. P 1.385
" of lemons, B. P 1.340
of mulberries, B. P 1.330
;, E. P 1.330
peel, B. P.
" of phosphate of iron, B. P
'■ of poppies, B. P 1,320
" of red poppy, B. P 1.330
" of '■ roses, B. P 1.335
" of rhnbarb, B. P
" of senna, B. P 1.310
" of squill, B. P
" of tolu, B. P 1.330
Treacle. B. P (about) 1.400
Hydrometers.— l^he specific gravity of liquids may be ascertained, without scales and weights, by means of an ht/droiiieier^an iastru- ment usually of glass, having a graduated Bt«m and a bulb or bnlbs, at the lower part. The specific gravity of a liqnid ia indicated by the depth to which the hydrometer sinks in the liquid, the zero of the scale marking the depth to which it sinks in pure water. Hy- drometers constructed for special purposes are known nnder the names of saccharometer, gafactometer, eteoraeter, nrinometer, alco- hometer. Hydrometera require a considerable quantity of liquid to fairly float them, and specific gravities observed with them are leas delicate and trustworthy than those obtained by the balance.
id .y Google
quantitative analysis,
Specific Gravity of Solids in Mass.
is) of any solid substance ranner. Then weigh it in water, by suspending it from a shortened balance-pan by a fine thread or hair and immersing in a vessel of water. The buoyant properties of the water will cause the solid to apparently lose weight : this loss in weight is the exact weight of an equal bulk of water. The weight of the sub- stance and the weight of an equal bulk of water being thus ascertained, a rule-of-three sum shows tho proportional weight of the substance to 1.000 of water. To express the same thing by rule, divide the weight in air by the loss of weight in water, the resulting number is the specific gravitj- in relation to 1 part of water, the conventional standard of comparison.
|
soineoftlie |
foUowiug pecitic griiifiPA - |
|
|
AlmYunium |
2.56 |
|
|
Anlimony |
6.71 |
|
|
Bismuth |
9.83 |
|
|
Ooma English Ko'd |
n.69 |
|
|
10.30 |
||
|
buuzf |
8.70 |
|
|
t.old |
8.95 |
|
|
19.34 |
||
|
Iron |
7.84 |
|
|
Lead |
11.36 |
|
|
Maguesmm |
1.74 |
|
|
M-»rble |
3.70 |
|
|
Fhosphurua |
1.77 |
|
|
Platinum |
21.53 |
|
|
Silvei |
10.53 |
|
|
&nlphur |
2.05 |
|
|
Tm |
7.29 |
|
|
7.14 |
Speoifl'" gravitiea of solid substances should be ta,ken in water having a temperature of about b(P F The body should be im- mersed about half an inch below the surface of the water; adhering aii^bnbblea must be tarefullj removed the body must be quite in- soluble in water.
Specific Gravity of Solids in Powder or Small
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 ;
id .y Google
BPEOIPIC GRAVITY. 429
again weigh. From the combined weights of water and substance subtract the amount due to the substance ; tlie residue is the weight of the water. Subtract this weight of water from the quantity which the bottle normally con- tains; the residue is the amonnt of water displaced by the substance. Having thus obtained the weights of equal hulks of water and substance, a rule-of-three sum shows the relation of the weight of the substance to 1 part of water, the specific gravity.
Or, suspend a cup, short glass tube, or bucket ftom a shortened balance-pan; immerse in water; counterpoise; place the weighed powder in the cup, and proceed as di- rected for taking the specific gravity of a solid in mass.
This operation may be conducted on fragments of any of the sub- stances the specific grayitiea 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 result should be identical. The specific gravity of shot is about 11.350 ; sand, 2.600 ; mercury, 13.5G.
Speoieio Gbavity op Solids Soluble in Watee.
Weigh a piece of sugar or other substance soluble in water; 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 deter- mined ; the loss in weight is the weight of an equal hulk of the turpentine. Ascertain the weight of an equal bulk of water by calculation: —
Sp. gr. of _ sp. gr, of . . observed , equal bulk turpentine ' water ' ' bulk of turp. ' of water. The exact weights of equal bulks of sugar and water being obtained, the weight of a hulk of sugar corresponding to one of water is shown hy a rule-of-three sum ; in other words, divide the weight of sugar by that of the equal bulk of water, the quotient is the specific gravity of sugar. The specific gravity of sugar ranges from 1,061 to 1,090.
Specific Gravity os Solids Liqhtbe than Water.
This is obtained in a manner similar to that for solids heavier than water; but the light body is sunk by help of a piece of heavy metal, the bulk of water which the latter displaces being deducted from the hulk displaced by both ;
id .y Google
430 QUANTITATIVE ANALYSIS.
the remainder is the weight of a bulk of water equal to the bulk of the light body. For instance, a piece of wood weighing 12 grammes (or grains) is tied to a piece of metal weighing 22 grammes, the loss of weight of the metal in water having been previously found to be 3 grammes. The two, weighing 34 grammes, are now immersed, and the loss in weight found to be 26 grammes. But of this loss 3 grammes have been proved to be due to the buoyant action of the water on the lead ; the remaining 23, therefore, re- present the same effect on the wood ; 23 and 12, therefore, represent the weights of equal bulks of water and wood. As 33 are to 12 so is 1 to .5217. Or, shortly, as before, divide the weight in air by the weight of an equal bulk of water; .5311 is the specific gravity of the wood. Another specimen of wood may be found to be three-fourths (.150) the weight of water, and others heavier. Cork varies from .100 to .300.
Specific Ghavitt of Gasbs.
This operation is similar to that for liquids. A globe exhauetol of air and holding 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. A rnle-of-three Bum shows their apeciflo gravity in relation to air or hydrogen, which- ever be taken as a standard.
Gorrection of the Volitme of Gases for Pressure. — The height of the barometer at the time of manipulation is Dot«d. Remembering the fact that " the bulk of a gas is inversely as the pressui-e to which it ia snbjected" (Boyle and Mariotte), a simple calculation shows the volume which the gas would occupy at 760 millimetres (or 29.922 inches), the standard pressure. (30 inches is sometimes adopted as the standard in England.*} Thus, 40 volumes of a gas at 740 milli- metres pressure are reduced to 89 when the pressure becomes 760 miDimetres(or aOvola.at 29ins. barom.become87 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 tP C. (320 F.) or 150.5 0. (60° F.), according to the standard taken. Gases expand about 0.3665t per cent, (jjj) of their volume at the
*In France the oonvenUonal atanjard lieiglit of the barometer is 760 millimetres at OO C. <32o p.) ; in England it is 30 inolies, the temperature of the mercurial column being 60O F. 760 millims. Is equivalent to 29.922 inolies ; but the expansion of the metal betneeu. 320 F. and 60O F. increases the length of tlie column to 30.005 fnolies. The standards are, therefore, almost identienl, difference in true length being couuterbalanced by the temperature at which the length ia ob- served.
t Corrected for the diffBreiice between the meronrial and air ther- mometers the coefficient of expauaioo of air is 0.003666 (Miller). Gases vary slightly.
id, Google
SPECIFIC GRAVITY. 431
fre&iing-^innt of water for every 0. degree (0.2036, or jjy for every P. degree) (EegDanlt). Thus 8 volumes of g-as at (p 0. willlDecome 8.293 at 10° 0. ; for if 100 become 103.665 on being increased in temperature lOO 0., 8 will become 8.293 (or if 100 become 102.036 on being increased 10° F., Swill become 8.1629).
Vw^or-d^aiaity. — Vapors are those gases which condense to liqnids at common temperatures. By the density of a vapor is meant its specific gravity. The density of a vapor is the ratio of any given volume to a similaT volume of air or hydrogen at the same tempera- ture and pressure. ■But, for eonveoience of comparison, this experi- mental Epeeific gravity is referred, by calculation aa just described for permanent gases, to a temperature of 0° 0., and 160 millimetres barom. A teaspoonful or so of liquid is placed in a weighed flask of about the capacity of a common tumbler and having a capillary neck ; ^e flask is heated in an oil-bath to a temperature considerably above the boiling-point of the liquid ; at the moment vapor ceases to ^cape, the neck is sealed by a blowpipe-flame, and the tempera- ture of the bath noted ; the flask is then remoTed, cooled, cleaned, and weighed; the height of the barometer is also taken. The neck of the flask ia next broken off beneath the surface of water or mer- cury (which rush in and fill it), and again weighed, by which its capa- city in cub. centims. 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 bulk of air* is obtained by a ^ule-of-three sum. This weight of air is dedacted ft-om the original weight of the flask, which gives the true weight of the glass. The weight 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 occnpied at the time of experiment is next corrected for temperature (to IP 0.) and pressure (760 millimetres) in the manner just described. The weight of a similar volume of hydrogen is next found.+ The weights of equal volumes of hydrogen and vapor being thus determined, the amount of vapor corresponding to 1 of hydrogen (the specific gravity or vapor-density) is shown by a short calculation. This process of finding the weight of a given volume of vapor is by Dumas. Gay- Lussac's consists in determining the volume of a given weight.
Experiment shows that, the specific gravities of many gases and
*1 onb. oeiitim. of air at 0° C. and 760 minims, weighs 0.001293 gramme.
fl litre (1000 cub. centims.) of hydrogen at 0° C. and 760 milli- metres (the barometer being at 0° C.) weighs 0.3096 gramme — a vol- tinie sometimes termed a critk (from KpiflS, krithi, a barley-corn — flgn- ratively, a small weight) ; thus a litre of osygen weighs 16 eiiths, chlorine 35.5 oriths, &c. 100 cnblc inches of hydrogen at 32° P. weigh 2.265 grains ; at 60° F. 2.143 grains (tha barometet being 30 ins. at 60O P. in both owes). 100 oubio inohes of air at 32o F. weigh 32.898 grains ; at 60O F., 30.935 (barom. 30 ins. at 60° p.). 1 oubio iiioh of water weighs 253.5 (363.458 at 62o F., and 30 in. bar.) grains. 1 gallon of water contains 277^ (277.274 at 620 F,) cubic inches.
id .y Google
432 QUANTITATIVE ANALySlS.
^apora on the hydrogen scale and the proportions in which they com- bine by weight ace identical. Thus, chlorine is 35.5 times as heavy as hydrogen, and 35.5 parts unite with 1 of hydrogen to form hydro- chloric acid gas. Hence, if the specific gravity of a gas or vapor is known, its combining proportion may be predieat«d with reasonable certainty, and vice verad. In applytna: this rule to gaaeoua or yapor- ous compounds, attention must be paid to the extent to whigh their constitnent gases contract at the moment of combination or expand at the moment of decomposition. Thus, steam is found to be com- posed of two volumes of hydrogen and one of oxygen, the three vo- lumes of constitaents condensing to two at the moment of combina- tion. Hence, steam may be expected to be nine times as heavy aa hydrogen, which experiment confirms.
These relations may be so expressed as to include both elementary and compound gases and vapors, thus; moleaviar weights and spe- cific weights are identical. Molecular weighte represent two volumes of a gas ; specific gravit;y conventionally represents the rela- tive weight or a gas compared with one volume of nydrogea or air ; hence the specific gravity of a gas or vapor on the H scale is found by calculation on simply dividing the molecular weight by 2 ; on the air-scale by dividing the hydrogen numbers by li.44 For example, —
H = 2. H = 1. Air
i U 22 1.524
; 46 23 1.593
28.88 14.44 1.000
These specific gravities closely correspond with those obtained by actual experiment. The specific gravity of any gas or vapor may therefore be calculated if the following data are at hand; (a) for- mula, (6) atomic weight of constituent elements ; these give the molecular weight, and the molecular weight dimded 6y 2 is the specific gravity on the hydrogen-scale. Specific gravity on the air- scale is then dedncible, if (c) the specific gravitv of air (14.44) in relation to hydrogen be remembered. The absolnte weight of axiy volume of a gas or vapor on the metric system is then obtainable if (d) the weight of a litre of hydrogen (0.0896 gramme) be known, or on the English plan by remembering (e) that 100 cubic inches of hydrogen at 00^ F. weigh 2.143 grains (100 cubic inches of air at 60° F. weigh 30.935 grams).
In confiraiation of these statemente regarding the mutual relation of specific gravity and atomic weight, a remarkable fact may be mentioned. Eegaault several years ago found the weights of 1 litre of hydrogen and oxygcu to be respectively .089578 and 1.429802
|
Hydrogen, |
n. |
|
Chlorine, |
01, |
|
Oxygen, |
Os |
|
Nitrogen, |
lb |
|
Sfeam, |
|
|
Ammonia gas. |
NH. |
|
Carbonic acid gas Alcohol (vapoiO, |
1, CO |
|
0,H„0 |
|
|
Air, |
id, Google
QUESTIONS AN!) EXERCISES. 433
gramme. The latter number divided by the former gives 15. 9G aa the specific gravity of oxygen. Stas, in recent experimental reaearclies on oombining-proportion, finds the atomic weight of oxygen to be not 16, but 15.96.
Exceptions to the law occur in a few compounds and in arsenieum and phosphorus, whose vapor-denaities are twice that indicated by the rule.
QUESTIONS AND EXEEOISES.
938. Define specific weight, or as it is commonly termed, specific gravity.
9391 In speaking of light and heavy bodies especially, what stand- ard of comparison is conventionally employed?
940. How are specifie gravities expressed in figures!
941. "Why shonld specific gravities be taken at one constant tem- perature ?
942. How does the huoyancy of air affect the real weight of any material 7
943. Describe the difference between density and specific gravity.
944. Give a direct method for the determination of the specific gravity of liquids.
945. A certain bottle holds 160 parts, by weight, of water, or 135.7 of spirit of winei what is the specific gravity of the latter? Ans. 0.9046.
946. Equal volumes of benzol and glycerine weigh 34 and 49 parts respectively, and the sp. gr. of the benzol is 0.850 ; what is the spe- cific gravity of the glycerine ? Ans. 1.225.
947. Explain the process employed in taking the specific gravity of solid substances in mass and in powder.
948. State themethod by which thespecificgravity of alightbody, snch as cork, is obtained.
949. What modifications of the usual method are necessary in ascertaining the specific gravity of substances soluble in water !
950. How is the specific gravity of gases determined ?
951. By what law can the volnme of a gas, at any required pres- sure, he deduced from its observed volume at another pressure !
952. To what ext«nt will 78 volumes of a gas at 39.3 inches ba- rometer alter in bulk when the pressure, as indicated by the barometer, is 30.2 inches?
953. Write a short account of the means by which the volumes of gases are corrected for temperature.
954 At the temperature of 15° 0. 40 volumes (litres, pints, ounces, cubic feet, or other quantity} of a gas are measured. To what ex- tent will this amount of gas contract on being cooled to the freezing- point of water (O© 0.} ?
Aitswer. As 1vol. of any gas at zero expands or contracts .003665 of a voi. for each rise or fall of 1© C, 1 vol. at 0^ 0. if heated to 15° C. will become increased by .054975 (that is, .003665) multiplied by 15), 1 vol. will expand to 1.054975. Conversely, 1.054975 vol. will
id .y Google
434 QUANTITATIVE ANALYSIS.
contract to 1 vol. if cooled from 15° 0. to 0° 0. And if 1.054975 becoinea 1 in wioling through 15^ C, 40 vols, will (aa found by rule- of-tiiree) contract to 37.916.
(The following five prohlems and solutionB are from Williamson's "Chemistry."}
955. 10 litres of oxygen are measnred off at 14° F. Eeqiiircd the volnme of the gas at 15® 0.
Answer. The first operation must be to rednce the temperature quoted in Fahrenheit's degrees to an equivalent valne on the Centi- grade scale. 140 F. is 18° below 32° P., t!ie freezing-point of water; and a range of 9° on the Fahrenheit's scale is equal to a range of 6*^ on the Centigrade scale, so that the temperature at which the oxygen is measnred off is — 1(P C. The rise of temperature up to 0° expands the gas in anch proportion that its volume at 6^ is to its volume at —UP as 1 is to 1— 0.03665, i. e. as 1 to 0.96335. The further rise of temperature from 0° C. to 15"^ expands the gas in the proportion ofl to 1+15x0.003665; i.e. 1 to 1.054975. The total rise of tem- perature therefore expands the gas in the proportion of 0.96335 to 1.054975.
0.96335:1,054975 -.-.lO-.x;
10X1.054975 ■■'" 0.06335 ^"■^^■
956. 230 cubic centimetres of oxygen are measured off at 14° C. and 740 millimetres mercurial pressure. Bequired the volume of the gas at the normal temperature and pressure (0*^ 0, and 760 millime- tres).
Answer. Let the reduction for change of temperature be made first. The proportion
1-1-14x0.003665 : 1 : : 230 : a;
957. A litre of oxygen is confined in a glass flask at 10° C. by the atmospheric pressure, added to that of a colnmn of mercury 60 mil- limetres high. The flask must be heated to 300° 0. without any increase of volnme taking place in the oxygen. How high most the column of mercury then be which presses on the gas, supposing the atmospheric pressure to remaiD constant at 760 millimetres ?
Answer. The oxygen is given at 10° 0. and 820 millimeti'ea pressure. If the pressure remained constant, the rise of temperature
id .y Google
QUESTIONS AND EXERCISES. 435
ffom 1(P 0. to 300° C. would expand the gas in such ppoportion that 1,03665 Toliime would expand to ^.0995 volumes. In order to pre- vent any expansion the pressare must be increased in the same pro- portion, whence
1.03665 :2.099S::820 :ic;
920x2.0995 ■■^= 1.03665 =^^^°'^-
Prom this total pressure the atmospheric pressure of 760 millimetres has to be deducted, leaving 900.6 millimetres as the height of the required mercnrial column.
958. A litre of oxygen is required of the density of 100 at IP 0. What weight of potassic chlorate must be used for its preparation, and what tota! pressure mast be applied to it?
Ansiver. The pressure required to compre^ oxygen from the den- sity of 16 to that of 100 is found by the proportion 16:100::76O:j:;
At the pressure of 4750 millimetres of mercury the weight of a litre of oxygen (16 grammes measure 11,2 litres at iP 0. and 760 millims. preeauce) is found by the proportion
whence
16X4750 _ *^~11.2xl60'
The weight of chlorate required for the evolution of 8.93 grammes of oxygen is touad from the proportion
48:122.5 ::8.93:ic; .-. ic= 22.8 grammes. I. What is the volume of 12 grammes of hydrogen at 15'^ C.!
= 8.93 grammes.
Ansmer. One gramme of hydrogen measures 11.2 litres at 0° 0., therefore 12 grammes measure 12x11.2=134.4 litres at (P. To find their volume at 15*^ C, we have the proportion
1 : 1+15x0.003665 : : 134.4 ; x ; whence
X = 134.4 X 1.054975 = 141,788 litres.
id .y Google
VOLUMETRIC ANALYSIS. APPARATUS.
The only special Vessels necessary in Tolnmetric quantitative ope- rations are ; 1. A litre Jtask, which, when filled to a, mark on the neck, contains one litre (1000 cubic centimetres, i. e. 1000 grammeB of ■water*) ; it serves for preparing solntions in qoantities of one litre. 2. A tall cylindrical gradwaiedKfre jar divided into 100 eqnal parts; it serves for the measnrcment and admixture of decimal or centesi- mal parts of a litre. 3. A graduated tube or burette, which, when filled to 0, holds 100 cubic centimetres (a decilitre), and is divided into 100 eqnal parts; it is used for aecorately measuring small volumes of liquids.
The best form of burette is Mohr's (with Brdmann's float). It con- sists of a glass tube about the width of a little finger and the length of an arm from the elbow, contracted at the lower estremitj and graduated. To the contracted portion is fitted a small piece of vul- canized caoutchouc tubing, into the other end of which a small spout made of narrow glass tube is tightly inserted. A strong wire eiarap effectually prevents any liquid from passing out of the burette unless the linobs of the clamp are pi^ssed by the finger and thumb of the operator, when a stream or drops flow at wiU. The accurate reading or the height of a solution in the burette is a matter of great im- portance. For this purpose a hollow glass fioat or bulb is used, of snch a width that it can move freely in the tube withont undue Wction, and so adjusted in weight that it shall sink to more than half its length in any ordinary liquid. A fine line is scratched round the centre of the float; this line mnst be always regarded as marking the height of tie fluid in the burette. In charging the burette, a solutioa is poured in, not until its surface is coincident with 0, but until the mark on the fioat is coincident with 0.
ESTIMATION OF ALKAIIES, ETC.
e than the formation of certain
2NH,H0 + Hjn,0j,2H,0 = (NH,),C,Oi,H,0 -|- 311^0
* A oubio centimetre is, striotly speaking', the volume occupied by one gramme of distilled water at its point of greatest density, namely, 4^^ C. metriLit measurements, however, are uniformly taken at lE0.r,5C. (SIPF.).
id .y Google
VOnUMETEIO ESTIMATION OF ALKALIES. 437
fiiots, that 70 parts of ammonia and 126 of oxalic acid yield 142 of cryataliized oxalate of ammonium and 54 of water. For formula represent molecules ; the weight of a molecule is the Bum of the weights of its atoms; and atomic weights are represented by definite invariable numbers (see the Table of atomic weights in the Appendix). As 126 parts ( = 1 molecnle) of oxalic acid combine with 70 parts ( =2 molecules) of ammonia, 63 (half of 126) of oxalic acid will unite with 35 ( = 1 molecule) of ammonia (NH^HO) ; 63 parts of oxalic acid will also unite with 56 of caustic potash (KE[0=56), 40 of caustic soda (NaHO^40), 100 of a«id carbonate of potassium (L.HCO = 100), 69 of anhydrous carbonate of potassium (KjCO„= 138) 84 f acid carbonate of sodium (NaHOOj = 84), 53 of anhy- dr us bonate of sodium (NaiOO, = 106), or 143 of erystalliaed a b t of sodium (NajOO^, 10H,O = 286). And if 63 parts of h d be dissolved in 100 yolumes of wafer, the stated weights f th ariou3 salts should he exactly neutralized by such a solu- t 143 parte of erystalliaed carbonate of sodium, for instance,
h Hid f pure, be exactly neutralized bj the 100 volumes of the X 1 a dsolution; andif a less number of volumes is required, the alt IS much per cent, impure. 143 parts by weight of a commer- ol mple of carbonate of sodium (common washing-" soda") re- q g nly 91 of the standard oxalic acid solution is thus shown to ta n 97 per cent, of pure carbonate of sodium, the remainder b purities. Further, the strength of solutions of ammonia,
d p tash, and lime may be accurately determined by adding to any d flu te quantity of them gradually, from a hnretle, a solution containing oxalic acid in known quantity, until exact neutralization is effected. If the quantity of oxalic acid required be 63 parts by weight (or 100 volumes of solution of oxalic acid containing 63 parfe, by weight, of the crystals), then the quantities of alkaline so- lutions employed contain, of potash (KHO) 56 parts by weight, of soda (NaHO) 40, of ammonia (NE.HO) 35 pai-ts, of slaked lime (Ca2B:0) 37, anhydrous lime (OaO) 28, &c. The strength of an alkaline solution, or, in other words, the proportion required toeffect neutralization of 100 volumes of the oxalic acid solution, having once been determined and decided by authority (B. P. e. g.), that quantity may always be expected to take 100 volumes of the oxalic acid liquid ; if less is required, the alkaline licjuid is so much per cent. weak.
The exact point of nentraliaabon of acid or alkaline liquids is ex- perimentally ascertained by litmus paper, or.more generally, infusion of litmus, which is turned red by the slightest amount of free acid, and blue by alkali.
Standabd Solution of Oxalic Acid. (Crystallized Oxalic Acid, H,0,0., 2H,0 = 126.) On account of the bivalent character of the oxalic radi- cal and the univalent character of most of the metals contained in the salts which are estimated by oxalic acid, it is convenient to take half the molecular weight of the acid for experiments, with the whole of the molecular 37*
id .y Google
438 QUANTITATIVB ANALYSIS.
weights of salts of univalent basylons radicals. The oxalic acid must be pure, leaving no ash when a gramme or so ia heated to redness in a porcelain or platinum cruci- ble; it must also be quite dry, but not effloresced.
Place 63 grammes of the crystals in a litre flask, add distilled water and shake till dissolved, diluting until the solution, at about 60° F., has an exact volume of 1 litre. Preserve in a stoppered bottle.
100 cubic centimetres of this solution contain ^^ of the molecular weight of oxalic acid in grammes, and will neutralize j^y of the molecular weight in grammes of a salt containing one atom of certain bivalent metals (as Ca2H0), or a salt {Na^CO, e. g.) containing two atoms of univalent metals, or y";, of the molecular weight in grammes of salts containing one atom of univalent radicals (such as KHCO,).
The following oflicial substances are tested with this solution. In those which are fluid there is commonly a alight variation in strength according as they are made by formulse of the British or U, S. Pharmacopceia.
* Ammonia, sohition of 17.00 = 100.0
" strong solution of 5.23 = 100.0
Ammonium, carbonate of, B, P. and U. S. P. 5.90 = 100.0
Borax, B. P. and U. S. P 19.10= 100.0
Lead, acetate of, B. P. and U. S. P. . . . 9.50 = 50.0
■' sol,ofanbacetateof,B.P.aadU.S.F. 51.03= 100.0
Lime, aqueous solution of, B. P. and U.S. P. 438.00 = 20.0
" aaccharated sol. of 45.30 = 25,0
Potash, caustic, B. P. and U. S. P. . . . ."i.fiO = 90.0 to 100.0
" BolutioD of 48.02 = 50.0
" water, effervescing 292,00 = 10,0
Potassium, bicarbonate of, B. P. and U. S. P. 5,00 = 50.0
acid tart, of, B. P. and U, 8. P. ie.80 = 100,0
carbouate of, B. P. and U. 8. P. 8,30 = 98.0 to 100.0
citrate of, B. P. and U. S, P. . 10.20 = 100,0
tartrate of, B. P. and U, S. P. . 11.30 = 100,0
Soda, caustic B. P. and U. S. P 4,00 = 90.0 to 100.0
" solution of 48.72 = 50.0
" water, effervescing 246.07 =^ 10.0
Sodium, bicarbonate of, B. P. and U.S. P, . 8.40 = 100.0
" and potasaiom, tart, of, B,P.andU.8.P.14,10 = 100,0
" carbonate of, B. P, and U. S. P. . 14,30 = 96.0 to 100,0
* The reading of tlis Table may be amplified thus ; 17 grammes
of the official Solution of Ammonia {Liquor Ammoniw, B. P.),carefuily
weighed, will require, for complete neutralJBatioii, if ot full strength, 100 cubic centimetres of the official volometrfo solution of osalic acid.
id, Google
VOLUMETRIC ESTIMATION OP ALKALIES. 439
Note 1. — The several Bnbstances diluted or tJissolved, as described in the following paragraphs, are conTeiiientty placed in a beaker, and the solution of acid run in cautiously from the burette.
Note 2. — A smaller number of e. c. of volumetric solution than 100, and a corresponding amount of substance to be tested, may be employed in anv case. But to ascertain percentage of impurity in the substance, the amount corresponding to 100 o. c. of the vol. sol. must be considered to have been used, the number of c. c. then wanting to make up 100 ia the percentage of impurity.
TJie solutions of ammonia require only the addition of solution of litmus, and the acid cautiously added until the last drop turns tbe liquid red. The amount of acid uaed previously to the addition to the portion that reddened tbe litmus indicates the proportional purity of the alkaline liquid. Thus, if only 50 c. c. are required, the solution is only half as strong as it ought to be ; if 93 c. c. are needed, the sol. of ammonia is 1 per cent, too weak, and so on. The actual quantity of aramonta (NH,HO) or ammoniacal gas (NH,) in the solutions is readily ascertained by ealcn- lation, thus: 100 c. c. of the acid solution have been em- ployed ; these contain ^g of the molecular weight of oxalic acid in grammes=6.3, and have neutralized ^^^ of the mo- lecular weight of ammonia in gran)mes=3,5 (or l.Y of NH,); 5.23 parts, by weight, of strong solution of ammonia (the amount employed in the experiment) contain, therefore, 3.6 of ammonia, NII,HO, or 1.7 of ammoniacal gas NH, ; now if 5,23 parts of a solution contain 3.5 of real ammonia (NH^HO), 100 parts will contain (by rule-of-three calcula- tion) 6T, and if the 5.23 contain l.i part of ammonia gas (NHg), 100 will contain 32.5 ; hence the Strong Solution of Ammonia, supposed to have been under examination, con- tains 67 per cent, of the hydrate or 32.5 per cent, of the gas. The formulce and molecular weights representing this process are as follows : —
2NH,H0 (or 2NH,) H,C,0.,2H,0
70 34 136
The carbonate of ammonitim should be dissolved in 30 or 40 c. c. of distilled water, infusion of litmus added, the standard oxalic acid solution allowed to flow in until the well-stirred liquid assumes a purple hue (due to the in- fluence of carbonic acid on the litmus), the whole gently warmed to promote evolution of carbonic acid gas, more standard acid then dropped in until the liquid again be-
id.y Google
440 QUANTITATIVE ANALYSIS.
comes purple, heat once more applied, and tlie operation continued until the last drop of acid turns the solution, red ; the height of the column of liquid in the burette before the last drop escapes represents the true amount of standard solution used, and hence the percentage of real carbonate of ammonium (of official quality) in the specimen on which the experiment was performed. The solution must be heated with care, or ammonia will escape. (Prac- tised analysts usually add excess of the standard acid aud thus fix every trace of ammonia; then gently boil to get rid of carbonic acid gas ; bring back the liquid to neutrality by an observed volume of standard altialine solution, and deduct an equivalent volume of acid from the quantity first flckled.) The formulse and molecular weights representing the process are as follows : —
N,nj,C,0, + 2(H^C,0„2H,0)
(vide p. 6T) (3 molecules)
As 252 parts of oxalic acid neutralize 236 of the so-called carbonate of ammonium, 6.3 of acid (or 100 vols, of its solution) will neutralize 5.9 of carbonate. If 5.9 grammes of carbonate be the quantity employed, and it does nvt require 100 c. c. of the volumetric solution, it is so much per cent. weak. Thus if, say 94 c. c. neutralize the salt, the latter is 6 per cent, weak (some ammonia gas has escaped, and,, consequently, an abnormal amount of acid carbonate NH,HCO„ is present). Any smaller quantity of salt than 5.9 grammes may be used ; in that case a rule- of-three sum must be worked to show how many c.c. of vol. sol. would have been employed if .5.9 grammes had actually been the amount under experiment.
The borax should be dissolved in several ounces of dis- tilled water. The formula and molecular weights repre- senting tlie process are as follows : —
2NaB0„ B,0„ 10H,O + H^C,0„ 2H,0
382 126
The solutions of the acetates of lead in distilled water may be rendered clear by the addition of a few drops of acetic acid. They must be well stirred after each addition of the solution of oxalic acid. The action is complete when the last drop of acid produces no more precipitate (oxalate of lead).
id .y Google
VOLUMETRIC ESTIMATION OF ALKALIES. 441
Pb2CJI,0„ 311,0 + H,C,0„2H,0
Pb.OSC.H^O, + 2(H,C,0„ 2H,0) 5i8 252
The solutions of lime require similar treatment. CaairO (orCaO) + n,c.,o^, SH^O
M 56 126
Solid caustic potanh or soda is never met with in a state of chemical purity, but should contain not less than 90 per cent, of the hydrate of potassium or sodium. The stand- ard acid is added to an aqueous solution of the hydrate, the termination of the action between the alkali and acid being observed by aid of litmus.
If carbonic acid be present, the mixture must be gently boiled before a final reading of the amount of acid added is taken.
aKHO or 2NaH0 + H^C,0„2H,0
112 80 126
The alkaline carbonates are often moist, and include traces of sulphates, chlorides, and silicates, but are suffi- ciently pure if containing, in the case of carbonate potas- sium 98 per cent., and carbonate of sodium 96 per cent., of the respective crystalline salts. The volumetric manipu- lations with these salts are similar to those for carbonate of ammonium. The strength of soda-ash is often reported in terms of " soda," that is, oxide of sodium (Na30=62). The old molecular weight of carbonate of sodium, 54 (it should have been 53), derived from that of "soda," 32 (it should have been 31), is still employed by manufacturers in reporting the strength of soda-ash. The true amount of soda equivalent to 54 parts of carbonate is 31.41 parts. A modern analyst having found the true amount of soda in a sample of soda-ash is expected by the manufacturer to report 31,41 parts for every 31, and 54 of carbonate instead of 53, and other quantities in proportion to these figures. One molecule of tartrate of potassium, or two of tlie acid tartrate^ yields one of carbonate when burnt, two molecules of citrate yielding three of carbonate under the
id .y Google
4i3 QUANTITATIVE ANALYSIS.
same circumstances. One molecule of the tartrate of po- tassium and sodium yields one of potassium carbonate and one of sodium carbonate. A volumetric estimation of the amount of carbonate thus produced affords indirect means of quantitatively determining the purity of the original salts.
K,C,H,Ob eq.to II,C,0„2H^0
326 126
2KB.CJiPs eq- to H,C,0^, 2H,0
376 126
2K,C„n^0, eq.to 3(n,Ci,0., 311,0
612 3T8
NaKC,n,0„, iJlfi eq. to 11,0,0., 2H„0
Alkalimetry. — The foregoing processes are often 8])olien of as those of alkalimetry (the measurement of alkalies).
Notes.
Neutral solution of litmus is prepared by digesting the commercial fragments in about fifteen or twenty times their weight of water for a few hours, decanting, dividing into two equal portions, adding acid to one till it is faintly red, then pouring in the other, and mixing. The solution may be kept in a stoppered bottle, but occasionally ex- posed to the air. It should never be filtered, but gradually allowed to deposit.
Standard sulphuric acid may be used in the place of oxalic acid if the latter cannot readily be obtained in a state of purity, 100 c. c. of the liquid containing gV "f ^^^ molecular weight of the pure acid in grammes. It ' \ paredbydilutingoilof vitriol with from three to f u tm s its bulk of distilled water, ascertaining how mu h i he acid liquid is required to exactly neutralize ^'^ ft! n lecular weight of pure carbonate of sodium tak u n grammes (5.3), and adding water until the obser d lun e of acid is increased to 100 c. c. Pure anhydro s a b n ate of sodium (Na^CO,) is obtained by heating the pure
id .y Google
VOLUMETRIC ESTIMATION OP ALKALIES. 443
bicarbonate to dull redness is a platinum or porcelain cru- cible for about a quarter of an hour. The coinmercial bicarbonate should be tested for chlorides and sulphates, which are usually present in smail quantities. Two or three hundred grammes may be purified by washing first with a saturated solution of bicarbonate of sodium and then cold distilled water until all trace of impurity has disappeared, drying over a water-bath, and then igniting to convert into carbonate.
Other quantities of salts than those stated in the foregoing and following Tables niBy be employed in volnmetric detcrmiaations, cal- calatiott giving any desired form to tie esperimental resnlts, an eicpert analyst thna aafing much time and material. In the case of snbBtancea which are liable to alter by exposnre to air, it is important that a selected quantity shonld be quickly weiglied, rather than selected weights be accurately balanced by material, the former operation occupying fflneh the shorter time.
Salts other than the official may be quantitatively analyzed by the volumetric solntiona, slight modifications of manipulation even enabling the processes to be adapted to fresh classes of salts. Ample instructions for extending operations in this manner will be found in Sutton's " Handbook of V olnmetrio Analysis."
QUESTIONS AND BXEE0ISE8,
060. Describe the various pieces of apparatus used in volumetric determinations.
961. One hundred cubic centimetres of solution of oxalic acid con- tain 6.3 grammes of the crystallized salt; what weights of bicar- bonate of potassium and anhydrous carbonate of sodium will that volume saturate t — Ana. 10 grammes and 5.3 grammes.
962. What weight of hydrate of potassinm is contained in solution of potash 48.02 grammes of which are saturated by 50 c. e. of the standard solution of oxalic acid? — Ans. 5.83 per cent.
963. State the percentage of hydrate of calcium in lime-water 438 grammes of which are nentraliised by 20 c. c. of the volumetric solution of oxalic acid.
964. Eight grammes of a sample of Eoohelle salt, after appropriate treatment, require 54.3 c. c. of the oxalic acid solution for complete saturation; what is the centesimal proportion of real salt present? — Am. 95.1.
ESTIHATION OF ACISS.
In the previous experiments a known amount of an acid has been used in determining unknown amounts of alkalii?B. In those about to be described a known simount of an alkali Is employed in estimat-
ed .yCoOglc
444 QUANTITATIVE ANALYSIS.
inff unknown amounts of acids. The alkaline salt fielected may bo a hydrate or a carbonate; but the former is to be preferred ; for the carbonic aoici, 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 soda, a solution of which has probably already been made the sub- ject of experiment in operations with the standard solution of oxalic acid. It should be kept in a stoppered bottle and exposed to air as little as possible.
Standard Solution of Soda.
(Hydrate of Sodium, NanO=40.)
100 c. C of the standard solution of oxalic acid are placed in a beaker with a little litmus, the tube or burette in which the acid was measured rinsed out, and the wash- ings poured into the beaker. A little strong solution of caustic soda is poured through the burette to rinse out ■water adhering to the tube and float (these rinsings thrown away), and the tube then filled to 0 with more of the alkar line liquid. The solution of soda is cautiously allowed to flow into the beaker until e.tact neutrality is obtained, the quantity noted, and, to every similar quantity of the whole bulk of the solution of soda, water added until the liquid measures 100 parts. If, for example, 93 c. c. of solution of soda have neutralized the 100 c. c. of acid, then 7 c. c. of distilled water must be added to 93 c, c. of the soda sola- tion, or 70 to 930 to make a litre. A sum of simple pro- portion will show to what extent any other quantity is to be diluted. Thus, if the bulk of soda solution remaining measures, say, 900 c. c, its volume must be augmented to gfiT.l e. c; for if 93 are to be diluted to 100, 900 must be diluted to 967.7.
100 c. c. of the soda solution contain -jV of the molecular weight (=4-)' taken in grammes, of pure hydrate of sodium, and will neutralize an equivalent quantity of any acid. That is, 100 c. c. will neutralize -^^ of the molecular weight in grammes of an acid containing one atom of any univ- alent acidulous radical, ^V of the molecular weight in grammes of an acid containing one atom of any bivalent acidulous radical, or ^„ of the molecular weight in grammes of an acid containing one atom of any trivalent acidulous radical.
id .y Google
VOLUMETillC ESTTMATIOiN OF AOIDS. 445
The following official acids are tasted with this solution : —
Ovimmss C. r, Qf
Acid, acetic '18.20 '= 100.0
" dilnted, B. F. and U. S. P. 70.29 = 50.0
" glacial 6.00 = 99.1)
" citric, B. P. aitd U. S. P. . . . 7.00 = 100.0
" hydrochloric, B. P. and U. 8. P. 11.48 = 100.0
diluted .... M.oO = 100.0
" nitric, B. P. and U. S. P. . . . 9.0O = 100.0
" " diluted 36.13 = 100.0
" nitroJijdrochlorie, diluted . . . 38.30 = lOO.O
" sulphuric, B. P. and U. S. P. . . 5.06 = 100.0
aromatic 36.65 = 100.0
diluted 35.90 = 100.0
" tartaric, B. P. and U. S. P. . . 7.50 = 100.0
Notes. — 1. In voinmetricalij' estimating tlie stvength of acids by an alkali, the indicator of neutrality ia the same as that used in testing alkalies by an acid, namely, litmus.
2. Pure acetates, citrates, tartrates, and some other or- ganic salts have an alkaline action on litmus, but not to an important extent. If the soda solution be added to acetic, citric, or tartaric acids, containing litmus, until the liquid is fairlj- blue, the operator will obtain trustworthy results. In delicate experiments turmei'ic may be used instead of litmus.
3. Six grammes of pure glacial acetic acid are neutra- lized by 100 c. c. of the standard solution of soda. But acid of this degree of purity is extremely difficult to pre- pare. The commercial acid contains only 1 per cent, of water, and is suflftcieatly pure for use in medicine.
Addtmdrif. — The operations for the quantitative analysis or measurement of acids ore often collectively spoken of uuder the name of acidtmetyy. They admit of considerable extension. (See the work previously cited.)
Percentage strength of Adds. — The poroentaffe strength of the seyeral acids and tueir official solutions is readily ascertained by calculation ia a manner similar to that given for alkalies. Thus the volumetric operation with the liquid commonly termed acetic acid is based on the reaction expressed in the following equation : — HC,H,Oj + NaHO = NaC3,0, + H,0.
AcetioiLeld. Sods. Acelnla of lodluni. Wator.
This equation, translated into parts by weight, means that 60 parts (the molecular weight) of true acetic acid are exactly neutraiiaed by 40 parts (themolec wt.) of soda. Supposing the quantity of " acetic acid" employed in the esneriment to have been that recommended in the Table (18.2 grammes), and that to neutralize it 100 c c. of the
id .y Google
446 QUANTITATIVE ANALYSIS.
soda solution have been nsed, and remembering that 100 c. c. of the soda solution contain 4 ^mmes of soda, it follows that the 1S.2 grammes of the liquid called acetic acid contain 6 grammes of real acetic acid; for if 40 {the molec. wt.) of soda neutralize 60 (the molec. wt.) of real acetic acid, 4 will neutralize 6. Lastly, if 18.2 contain 6, 100 will contain 33; the so-calted acetic acid (really an aqueons solntion) contains 33 per cent, of true acetic acid (HOjHj 0,).
If the 18.2 grammes have taken, say, 93, instead of 100 c. c, the aeid liquid is ^ per cent, weak ; in otherwords, it contains only 30.7 per cent, of real acid; for (by mle-of-three) if 100 c. c. added to 18.2 grammes indicate 33 per cent., 93 c. c. added to 18.2 grammes indicate 30.1 per cent.
The remaining acids react with the alkaline salts in the manner and to the extent indicated by the following formula and molccnlar weights : —
H^O^HjO,, H,0 + 3NaH0
210 120
36.5 40
TT^SOj + 2NanO
TT^C.H.Oj + 2NnU0
QUESTIONS AND EXERCISES.
965. What percentag-e of real acid is present in diluted sulphuric acid 30 grammes of which are neutralized by 84 c. c. of the official volumetric solution of soda! — Ana. 13.72.
966. How much real nitric acid is contained in a solution 36 grammes of which wee saturated by 94 c. e. of the standard solntion of soda ?— ^ms. 16.45 per cent.
ESTIMATIOIT OP ACIDULOUS RADICALS PEECIPI- TATED BY NITBATE OF SILVEB,.
The purity of many salts, and the strength of their solutions may be determined by this process ; but at present only three official sub- stances {namely, diluted hydrocyanic aoid, bromide of potassium, and arseniate of sodium) are quantitatively analyzed by standard soln- tion of nitrate of silver. The reactions on which the success of the process depends are expressed in the following equations ; — ( AgNOH-2Na0y=NaOyAgOy-fNaNO3, 1 NaOyAgOy+AgN03=2AgCy+NaNO, ; KBr+AgN"0,=AgBr+KN03 ; Na,HAsO,+3AgN03=AgsAsO,+2NaN03+HNOs.
id .y Google
volumetric estimation op acids, 44t
Standard Solution of Nitrate op Silver.
(Nitrate of Silver, AgNO^ = ITO.)
Dissolve 17 grammes of ciystals of pure nitrate of sil- ver Id 1 litre of water. 100 e, c. of this solution contain yJij of tlie molecular weight in grammes of nitrate of sil- ver, and will decompose an equivalent quantity of a salt of any acidulous radical yielding silver compounds insolu- ble in water.
Acid, hydrocyanic, diluted, B.P.andU.S.r." sVoO ^'ioo^d Potassium, bromide of, B. P. and U. S. P. . 1.19 = 100.0
Sodium, araeniate of (dry) 62 = 100.0
Diluted hydrocyanic acid is converted into cyanide of sodium by adding caustic soda until, after stirring, litmus shows that the liquid has au alkaline reaction. The nitrate- of-silver solution is then allowed to flow in gradually, until, after thorough agitation, a slight permanent turbidity re- mains. When this occurs, the quantity of nitrate of silver added represents exactly half the amount of real hydro- cyanic acid present in the diluted preparation. Thus the 100 c. c. of standard solution contains xJu of the molecu- lar weight, in grammes, of nitrate of silver (=1.7) ; this would ordinarily correspond, in a case of complete decom- position, to T^u of the molecular weight in grammes of hydrocyanic acid (=.27); 27 grammes of the diluted acid, the quantity employed in the experiment, apparently con- tain therefore ,27 gramme of real acid, equal to 1 per cent, A glance at tlie equation shows that at the moment cyanide of silver begins to be precipitated, only half of the cyanogen has been converted into cyanide of silver ; the quantity of acid indicated by the amount of nitrate added must there- fore bo doubled for the non-ect percentage (=2). 2HNC eq. to AgNO,
54 170
Bromide of polassium is dissolved in distilled water in a beaker, and the standard solution added until, after agi- tation of the liquid and subsidence of the bromide of silver, a drop of the solution of nitrate of silver gives no more precipitate.
KBr + AgNO,
119 17'l
id .y Google
448 QUANTITATIVE ANALYSIS,
Arxeniale of sodium (Wa^HAsO^TH^O) must be dried at 300° F, before weighing. It is thus reduced to a definite anhydrous salt (If a^HAsOJ, losing, if pure, 40.38 per cent. of water. The weighed residue is dissolved in distilled water, and treated as described in the previous paragraph, Ka,HAsO. + SAgKOg
186 510
Spirit of Wine (Smritvs Rectifieaiw, B. P.) may contain traces of amylie alcohol and aldehvd ; these maj' be detected by nitrate of silver, which is reduced by them to the metallic state. Any quantity beyond a mere trace of snch bodies renders spirit of mine too impare for use in medicine, "Four fiuidounces with thirty grain-measures (about two cub. cent} of the volnmetric solution of nitrate of silver exposed for twenty-fonr hours to bright liglil, and then decanted from the black powder which has formed, undergoes no further change when again exposed to light with more of the test."
QUESTIONS AND EXERCISES.
967. Explain the volumetric method of estimating the strength of aqueous solutions of hydrocyanic acid.
96B. How much nitrate of silver will indicate, by the official volu- metric process, the presence of 1 part of real hydrocyanic aci<S ?
ESTIMATION OF SUBSTANCES EEADILY OXIDIZED.
Any substance which quickly absorbs a definite amount of oxygen, or is susceptible of any equivalent action, may he quantitatively tested by ascertaining how much of au oxidizing agent of known power must be added to a given quantity before complete oxidation is effected. The oxidizing agents employed for this purpose in the Britirfi Pharmacopceia are iodine and the red chromate of potassium ; permanganate of potassium is often used for the same purpose. Iodine acts indirectly, by taking hydrogen from wafer and liberating oxy- gen ; the red chromate of potassium directly, by the facility with *hich it yields three-sevenths of its oxygen— as indicated by the eqnatlons and statements given on pages 451 and 452.
Standard Solution of Iodine. (Iodine, I=12T.)
Prepare pure iodine bj-mixing the commercial article with about, a foiirtli of its weight of iodide of potassium and »\\)t-
id.y Google
VOLUMETRIC ESTIMATION OF DEOXIDIZEES. 4i9
liming. SubUraation may be effected by gently warming the mixture in a beaker, the mouth of which is closed by a funnel ; the iodine vapov condenses on the funnel ; while fixed impurities are left behind, and any chlorine which the iodine may contain is absorbed by the iodide of potassium, an equivalent quantity of iodine being liberated. Small quantities may be similarlj' treated between two watch- glasses, placed edge to edge. Any trace of moisture in the resiiblimed iodine is removed by exposure for a few hours under a glass shade near a vessel containing oi! of vitriol.
Place 12. T grammes of pureiodine and about ISgrammea of pure iodide of potassium (an aqueous solution of which is the best solvent of iodine ; the salt plays no other part in these operations) in a litre flask, add a small quantity of water, and agitate until the iodine is dissolved, dilute to 1 litre. 100 c. c. of this soliition contain y J j^ of the atomic weight of free iodine in grammes, and, water being present, will cause the oxidation of jj^ of the molecular weight of sulphurous acid (H^SOJ in grammes (=,41), or ^Bu (=-32) of sulphurous acid gas (SO,) sulphuric acid being formed. 100 c. c. will also oxidize jjg of the molec- ular weight of arsenioua acid (HjAsO,) in grammes, or jjjj of the molecular weight of common white arsenic (AsjO,) in grammes (=.495), arsenic acid (HjAsOJ being produced. The reactions are expressed in the following equations : —
1^4- n.,0+H,S03=2HI + HSO,.
I +2H.;0 + S0„=2HI-I-H,S0..
l,-i-H,0-l-H3AsO,=2HI-fH,A80,.
3I,,-l-5H,0-l-AsA=4HI-|-3H,AsO^. I^-l-2{Na,SA.5H,O)=3NaI-|-Na.,S,O„-f-10H,O. The following ofiBcial substances are tested with the standard solution of iodine: —
Acid, solution of sulphurous .... 3.4T = 100
Arsenic, in mass, B. P. and U. S. P. . . 0.495 = 100
" malkB\ineaol.(Liq.Ar^emcaUs)bi.&i = 100
" insicidaol.(Liq.Arsen.S'ydrochL)5i.^i = 100
Sodium, hyposulphite of 2.48 = 100
The solution of sulphurous acid is diluted with three- fourths of a litre of cold water, and the iodine solution added until a slight permanent brown tint ia produced, 38*
id .y Google
450 QUANTITATIVE ANALYSIS.
showing the presence of free iodine. A better indicatiou of the termination of the action is affoided by mucilage of starch, which gives a blue color witb the slightest trace of iodine. As already stated, 100 c. e. of this volumetric solution contain an amount of free iodine sufficient to cause the oxidation of ^^n of the molecular weight of either sulphurons acid or sulphurous acid gaa. Now ^J^ of the molecular weight of sulphurons acid (H^SOJ in grammes _is 0.41 ; if 3.47 grammes of the solution contain O.il of the acid, 100 of the solution will be found to con- tain 11.8. By a similar calculation the official solution may be shown to contain, or, rather, yield 9.23 per cent, of sulphurous acid gas (SO,).
If the sulphurous acid be diluted to a less degree than .Oi or .05 per cent., there will be some risk of the sulphuric acid formed being again reduced to sulphurous acid, with liberation of iodine. In delicate experiments the distilled water used for dilution should previously be freed from air by boiling, to prevent the small amount of oxidizing action which dissolved air would exert.
H^SO, eq. to I, j SO, eq. to I,
82 254 1 64 254
The solid arsenic is dissolved in boiling water by help of about two grammes of bicarbonate of sodium. When the liquid is quite cold, mucilage of starch is added, and the iodine solution allowed to flow in until, after well stir- ring, a permanent blue color is produced,
HjAsO, eq. to I, 1 As^Oj eq. to 21^
126 2,54 I 198 508
The arsenical solution already containing some carbonate of potassium requires only about one and a half gramme of bicarbonate of sodium for neutralization of the arsenious acid. After boiling and cooling, starch and the iodine solution are added as before.
Th.e solution of arsenic in dilute hydrochloric acid requires about three grammes of acid carbonate of sodium, if 54 or 55 grammes of solution is the quantity employed. After boiling for a few minutes and cooling, the starch and iodine are added.
These arsenical solutions contain .9 per cent, of arsenic. The Hyposulphite of sodium is dissolved in water, star'cb
id .y Google
mucilage added, and the iodide 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 oxidizing agent by uniting with the hydrogen and thus liberating the oxygen of water. In tlie present case it unites with an analogue of hydrogen, namely, sodium.
QUESTIONS AND EXERCISES.
96B. Give equations illustrative of the reactions on which the use of a standard volumetric solution of iodine is based.
970. From what point of view may iodine he regarded as an oxi- dizing asent!
971. what reagent indicates the termination of the reaction be- tween deoxidizing substances and moist iodine ?
972. How maeh salphurous acid gas will canse the absorption of 2.54 parts of iodine in the volnmetrio reaction?
973. What quantity of iodine will be required, under appropriate conditions, to oxidize 5 parts of arsenic ?
97i. Find by calculation the amount of bypoaulphife of sodium equivalent to 13 parts of iodine in volumetric analysis.
S-TAKDAHn SoLLTlOff OP EbD OhBOMATR OF PoTASSIUll.
(Red Chromate of Potassium, K^OrOj, Cr03=295.) One molecule of red chromate of potassium in presence of an acid, under favorable circumstances, yields four atoms of oxygen to the hydrogen of the acid, leaving three available either for direct oxida- tion or for combination with the hydrogen of more acid, an equiva- lent proportion of acidulous radical being liberated for any required purpose.
f;. when used as a volumetric agent, the red chromate always yields the whole of its oxygen to .the hydrogen of the accompanying acid, a corresponding quantity of acidulous radical being set free — four- sevenths of this radical immediately combining with the potassium and chromium of the red chromate, three-sevenths hecommg avail- able. Ferrous may thus be converted into ferric salts with sufficient rapidity and exactitnde to admit of the estimation of an unknown quantity of iron by a known quantity of the red chTOmate. As one atom of the liberated acidulous radical will convert two molecules of ferrons into one of ferric salt, one molecule of red chromate causes six of ferrous to become three of ferric, as shown in either of the fol- lowing equations: —
K,CrO,, Or03+7H^O.+GFeSO,=KjSO.+ Cr,3SOj+7H,0
+3(Fe,3SOj);
IC,CrO„ CrO;,-f UnCI+CFeCI,=2Kai+ Cr,Cl,+7H,0 + 3Fe,0!^,
id .y Google
These equations indicate that, in presence of excess of acid, 295 parts (the molecular weight) of red cnromate of potassium will con- vert 1668 parts of crystallized ferrotis sulphate, 6(Fe80y 7HjO= 278), or an cciuivalent quantity of ferrous chloride (6FeCL=762), ferrous carbonate (6FeC05=696), ferrous arseniate (2Fe3A8jOs^ 892), ferroas phosphate (2FesP,08=716), or iron itself (3Fe,,=336), into ferric salt, if these parts be ta,keii in grammes, j^^ or less of the stated amounta will be found to be couveaieat quantities for experiment.
Dissolve 14.15 grammes of red chromate of potassium in one litre of distilled water. 100 c. c. of this solution con- tain g^u of the molecular weight of the salt in grammes, and wilf cause the conversion of g^^ of the weight of 6 atoms of iron in grammes, or an equivalent quantity of the lower salts of iron, from the ferrous to the ferric state.
The solution is used in determining the strength of the following official ferrous preparations. It is known that the whole of the ferrous has heen converted to ferric salt when a small drop of the liquid placed in contact with a drop of a very dilute solution of ferridcyanide of potas- sium, on a white plate, ceases to strike a blue color.
Iron, arseniate of 2.94 = 25
" magnetic oxide of 2.41 = 10
" phosphate of, B. P. and U. S. P. . 2.00 = 25 " saccharated carbonate of . . . 4.70 = 50
The several compounds are dissolved in excess of hydro- chloric acid diluted with water, and the standard solution then dropped in. The ferrous liquid must not be exposed to the air for more than a few seconds after solution has been effected, or oxygen will be absorbed and a cori-es- ponding amount of ferric salt formed before the volumetric oxydizing agent is added: in most cases diluted sulphuric acid may be used as a solvent of the ferrous salt, ferrous sulphate absorbing oxygen from the air far less rapidly than ferrous chloride. It will be found that the propor- tion of carbonate of iron in the saccharated compound, as indicated by the above numbers, is 37 in 100. The theo- retical percentage obtainable from the ingredients is 45.5, the quantity that would be present if the compound were anhydrous and unoxidized, conditions never obtained in practice.
The use of these two volumetric solutions in quantita- tive analysis admits of great extension.
id .y Google
VOLUMETRIC ESTIMATION OF OXIDIZERS.
QUESTION'S AND EXERCISES.
975. Write equations explanatory of the oxidiziag-powei- of red chromate of potassium.
976. One hundred cubic centimetres of an aqueoas solution of red chromate of potassium^ contain iJj of the moleculai- weight of the salt in graBimea ; what weight of metallic iron, dissolved in hydro- chloric acid, will this volume oxidize ? — Ane. 1.68 gramme.
917. If 8.34 grammes of a specimen of crystallized ferrons sul- phate require 93 e. c. of the standard solution of chromate for com- plete oxidation, what percentage of real salt is present? — Am. 93.
978. How much redT chromate of potassium is required for the con- version of 10 parts of ferrous sulphate into fferric salt t
979. What quantity of pure terrous carbonate is indicated by 1.475 part of red chromate as appUed involnmetric analysis!
980. State the amount of official saccharated carbonate of iron equivalent to .7375 part of red chromate in the volumetric reaction.
ESTIMATION OF SUBSTANCES READILY DEOXIDIZED.
Any substance which quickiy yields a definite amount of oxygen may be quantitatively tested by ascertaining how much of a deoxi- dizmg agent of known power must be added to a given quantity be- fore complete deoxidation is effected. The chief componnds which may be used as absorbers of oxygen (deosidizers or reducing agents, as they are commonly termed) are hyposulphite of sodiiim, sulpha- roaa aeid, ferrous sulphate,* oxalic acid, arsenioas ajjid. The first- named is oificiaily employed ; it is only used in the estimation of free iodine, and, indirectly, of chlorine and chlorinated compounds. Iodine and chlorine are regarded as oxidizing agents, because their great alfinity for hydrogen enables them to become powerful indirect oxi- dizers in presence of water.
Standard Solution of Hyposulphite. of Sodium.
(Crystalli!;eiaHyposu!phiteofSoc!ium,NajSp3,5HjO=248.)
Dissolve about 30 grammes of hyposulphite of sodium in a litre or less of water. Fill a burette with this solu- tion, and allow it to flow into a beaker containing exactly 100 c. c. of the volumetric solution of iodine until the brown color of the iodine is just discharged — or, starch being added, until the blue iodide of starch is decolorized.
* " Five grains of PermanRanate of Potassium dissolved in water require for decoloration a solution of forty -four grains of granulated sulphate of iron acidulated with two fluidraohms of diluted sulphu-
id.y Google
4f)i QUANTITATIVE ANALYSIS-
Note the number of c. e. of iij'posiilpliitc solution required, and to the bulk of the solution add water, so that 2.48 gi'ammes of hyposulphite of sodium shall be contained in every 100 c.c.
When iodine and hypoBulphite of sodium react, two atoms of iodine remove two of BOoium from two molecules of the hyposulpliite, tetrathiouate of sodium being formed, as indicated ia the following equation : —
I, + 3Na,S,0j = 2NaI + Na^S^O^.
As, therefore, 100 c. c. of the iodine solation contaia yjj of the atomic weight of iodine in gi'ammes, 100 c. c. of the standard solu- tion of hyposulphite of sodium will contain yfj of the molecular weight of the salt in grammeB, and will show the existence of yj^ of the atomic weight of iodine in grammes ia any quantity of a liquid normally containing free iodine, or iodine liberated by an equivalent quantity of free chlorine.
This solution is employed for quantitatively testing the following substances ; —
Chlorine, solution of 29.26 = 50
Iodine, B. P. and U. S. P 1.37 = 100
Lime, chlorinated 1.17 = iOO
" solution of chlorinated . . . 6.00 = .^0
Soda, solution of chlorinated . , ■ 1.00 = 50
Note. — Owing to the volatility of chlorine and iodine, and the readiness with which they attack the metals of which balances are made, it is not desirable to experiment on stated weights of substances containing these elements. A small stoppered bottle or tube containing the material may be counterpoised, and a convenient quantity removed for analysis, the precise amount taken being ascei'tained by again weighing the bottle.
The iodine may be dissolved in water containing about a gramme and a half of iodide of potassium, a salt giving no reaction with hyposulphite of sodium.
I, eq. to 2(N"a,Sp„ 5HP) 254 496
The solution of chlorine is added to water containing excess of iodide of potassium (about a gramme and a third) ; a quantity of iodine, equivalent to the amount of
id .y Google
VOLUMBTKIC ESTIMATION OP OXIDIZERS. 455
chlorine present, is thus liberated. The hyposutpliite solution is then dropped in.
CI, eq. to 3(NaA0Bi 5H^0)
71 496
The chlorinated lime ("chloride of lime" or "bleaching- powder") is mixed with about a fifth of a litre of water containing excess of iodide of potassium (3.5 grms.) and acidulated with hydrochloric acid. The available oxygen of the chlorinated lime liberates chlorine from aa equiva- lent quantity of hydrochloric acid ; and this, with the available chlorine of the chlorinated lime, sets free an equivalent amount of iodine from the iodide of potassinm. The hyposulphite and iodine reacting show the direct and indirect oxidizing power of the chlorinated lime; it should correspond to 30 per cent, of chlorine. For example, as 2*8 (1 molecule) of hyposulphite indicate the presence of 35.5 (1 atom) of chlorine, 3.48 of hyposulphite (the quan- tity in 100 c. c.) indicate the presence of .355 of chlorine. If 100 c. c, have been used, therefore, .355 of chlorine is obtainable from the quantity of bleaching-powder employed (1.17)- And if 1,11 of bleaching-powder yield .355 of chlorine, 100 will yield about 30 (30^ nearly).
The aolut-hn of chlorinated lime is mixed with about a fifth of a litre of water containing a couple of grammes of iodide of potassium, and ten or twelve c. c. of hydro- chloric acid. The hyposulphite solution is then added from a burette until the color of the liberated iodine is just dis- charged. The solution of chlorinated soda is similarly treated.
Note. — 1. In these experiments the blue color formed on the addition of mucilage of starch to the liquids will be found to be a more delicate indicator of the termination of reactions than the brown tint of the iodine.
iVbfe. — 2. Standard solntions used in voiumetric analysis are often described as Bormal, decinormai, and centinormal. A normai soln- tion (N) contains in every litre the molecnlar weight of the salt, taken in grammes ; a decinormai solution is one tenth (y'g), and a centinormal {x"j) one hundredth the strength of such a normal solu-
id.y Google
QUANTITATIVE
QUESTIONS AND EXERCISES.
9Sl. For what purposes is the official volumetric solution of hjpo- sulpliite of sodium used ?
982. On what reaction is based the quantitative employment of hyposulphite of sodium ?
983. How much hyposulphite of sodium is required to show the presence of 10 parts of iodine ?
984. To what amount of chlorine is 4.96 parts of hyposulphite of sodium equivalent in volumetric analysts ?
985. Describe the operations included in the estimation of the strength of bleach ing-powder.
986. By what reagent is the complete absorption of free iodine by hyposulphite of sodium indicated?
MISCELLANEOUS PROBLEMS.
987. How much bicarbonate of potassium is contained in an eight- ounce bottle of medicine, seven fluidraohms of which are saturated by two and a half grains of crystallized oxalic acid ?
988. A sample of soda-ash is said to contain 78 per cent, of pure anhydrous carbonate of sodium ; if the statement is troe, how much of the official volumetric solution of oxalic acid will saturate 5 ■ grammes of the specimen !
989. 2.69 grammes of common brown sulphuric acid are saturated by 43.6 cubic centimetres of the official volumetric solution of soda ; how much acid of 96.8 per cent, is present ?
990. Four grammes of a litre and a half of concentrated hydro- cyanic acid are neutralized by 89 cubic centimetres of volumetric solution of nitrate of silver of official strength ; to what volume must the bulk of the acid be diluted for the production of acid of pharma- copceial strength ?
991. 3.18 grammes of a powder containing arsenic require for complete reaction 84 cubic centimetres of a volumetric solution of iodine, which is 1.43 weaker than the standard solution of the British Pharmacopeia ; what percentage of pure arsenic is contained in the powder 1
992. How much pure metal is present in a sample of iron 1 68 gramme of wlHi,h di^^solved in dilute sulphuric acid is exacllj attacked by 9.i.7 lubie centimeties of a 'icmi dei'inormil vohinipfiir solution of red chiomit( of potassium nhich ii 6 pii Lent too strong ?
id .y Google
OBAVIMETKIO ESTIMATION OF rOTASHIUM. 457
GKAVIMETRIC ANALYSIS.
ESTIMATION OF xMETALS.
poTAssitrar.
OutUne of the Process. — This element is uanally estimated in the form of double chloride of potassium and platinum. Qualitative anaiysJB having' proved the presence of pota^ium and other ele- ments in a substance, a small quantity of the materia! is accurately weighed, dissolved, and the other elements removed by appropriate reagents ; the precipitates are well washed, in order that no trace of the potassinm salt shall be lost, the resulting liquid concentrated over a water-bath (to avoid loss that would occur mechanically during ebullition), hydrochloric acid added if necessarj, sointion of perchloride of platinum poured in, and evaporation continued to dryness; excess of the ^rchloride is then dissolved by adding spirit of wine containing' half its bulk of ether {a liquid in which the double chloride is insolnble), the mixture carefully poured on to a tared and dried filter, washed with the spirit till every trace of free per- chloride of platinum is removed, the whole dried and weighed; from the resulting amount the proportion of potassium, or equivalent qnantity of a salt of potassinm, ia ascertained by calcalation.
Note. — From this short description it will be seen, first, that the chemistry of quantitative is the same as that of qualitative analysis ; the second, that the principle of gravimetric is the same as that of volumetric quantitative analysis: the combining-
Scoportions being known, nnknown quantities of elements may e ascertained by calculation from known quantities of thoir compound. Apparatus. — In addition to a delicate balance and weights and tbe common utensils, a few special instru- ments are used in quantitative manipulation; some of these may be prepared before proceeding with tbe estima- tion of potassium.
Filtering-paper should be of the kind known as Swedish, the texture of which is of the rtquisite degree of closeness, and its ash small in atnotmt, 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 heated and the paper consequently burnt, the weight of the ash of the filter must be deducted from the weight of the residue. The ash is estimated by burning ten or twenty of the cut filters. These are folded into a small compass, a portion of a piece of platinum wire twisted a few times round the
id .y Google
458 QUANTITATIVE ANALYSIS.
packet, so as to form a cage, the whole held by the free end of the wire over a weighed porcelain crucible placed in the centre of a sheet of glazed paper, the bundle ignited by a spirit-lamp or smokeless gas-flame, the flame allowed to impinge against the charged mass till it falls into the crucible below, any stray fragments on the sheet carefully shaken into the crucible, the latter placed over a flame till carbon has all burnt off and nothing but ash remains, the whole cooled, weighed, and the weight of the crucible de- ducted ; the weight of the residue divided by the number of pieces used gives the average amount of ash in each filter.
Apair of Weighing-tubes, for holding dried filters during operations at the balance, may be made from two test-tiibes, one fitting closely within the other. About five centimetres of the closed end of the outer and seven of the inner are cut off, by leading a crack round the tube with a pencil of incandescent charcoal, and the sharp edges fused in the blowpipe-flame. A filter, after drying, is quickly folded and placed in the narrower tube, the mouth of which is then closed by the wider tube. This presents reabsorption of moisture from the air.
The Washing-bottle, holding the epirii of wine and ether, is a common bottle, 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 stream of the liquid. The bottle being inverted, the warmth of the hand expands the air and vapor to a sufficient ex- tent to force out the liquid.
The Ordinary Washing-hoUle for quantitative operations should be formed of a flask in which water may be boiled, fitted up as usual {vide p. 81).
A Water-oven, ia the best form of drjing-apparatna. It is a small sjjnare copper veaael, jacketed on five aides and having a door ou the sixth ; water is poured into the space between the inner and outer easing', and the whole placed over a gas-lamp or other scarce of heat, moist air and steam escaping by appropriate apertures, I>esiccation at higher temperatures tnan the boiling-point of water may be prae- tisedoy using oil or paraffin instead of water, inserting a thermome- ter in the fat. The apparatus may be purchased of any maker of chemical instruments.
Pure distiUed tuatet- must be used in all quantitative determina-
Nbte. — In practising the operations of quantitative analysis, experiments should at first be conducted on definite sails of known composition. The accuracy of ri^siitts miij then bo tested by calculation.
id .y Google
GRAVIMETRIC ESTIMATION OF POTASSIUM. 4o9
Estimation of Potassium in the form, of double chloride of potassium and platinum. — Select two or three crystals of pui-e nitrate of potassium, 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, accurately weigh the selected quantity, trans- fer to a small dish, letting water from a wash-bottle flow over the watch-glass and run into the dish, warm the dish till the nitrate is dissolved, acidulate with hydrochloric acid, add excess of aqueous solution of perchloride of pla- tinum fa quantity containing about 0,4 of solid salt), evaporate to dryness over a water-batli. While evapora- tion is going on, place a filter and the weighing-tubes in the water-oven, exposing them to a temperature of 213° F. for about half an hour ; fold the filter aud insert it in the tubes, place them on a plate imder a glass shade, and when cold accurately note their weight. Arrange the weighed filter in a funnel over a beaker. Transfer the dried and cooled platinum salt from the dish to the filter by moistening the residue with the mixture of alcoliol and ether, and, when the salt is loosened, pouring the contents of the dish into the paper cone. Any salt still adhering may be ft-eed by the finger, wliich, together with the dish, should be washed in the stream of spirit, the rinsings at once flowing into the filter. The filtrate should have a yellowisli-brown color, due to the excess of perchloride of platinum. If it it is colorless, an insufficient amount of perchloride has been added, and tlie whole operation must be repeated. The washed precipitate and filter are finally dried in the water- oven, folded and placed in the weighing-tubes, the drying continued until the whole, after repeated weighing when cold, ceases to alter ; the final weight is noted.
Note. — If filters are not freed from all trace of ai^id by thorough washing, the paper will be brittle when dry, failing to pieces on being folded.
Analytical memoranda in the note book may have the following form : —
Watch-glass and substance . .
Watch-glass
Substance
Weighing-tubes, filter, and Pt salt .
Weighing-tubes and filter . . , PtCl.,2KCl.
id .y Google
Tlie ealeulations are simple: —
^^1 =489 I are equivalent to | =2Qi\
( the weight of "i
so -J double ohioricleyave equivalent tea;, x will be the
( obtained ) amount of pure nitrate of potassium in the quantity of suh- stance operated on, x should, in the present instance, be identical with the weight of substance taken, because, foi- educational purposes,pure nitre is undei-examination. Only after analyses of pure substances have yielded the operator results identical with those by calculation, can analyses of substances of unknown degree of purity be undertaken with confidence. A table of atomic weights, ftom which to find molecular weights, is given in the Appendix
A Water-bath foe the evaporation of liquids or for dijing moist solids at temperatures below 212*^ P. is an iron, tin, or eartliennare pan, the mouth of wliich can he narrowed by iron or lin diaphragms of various sizes and having orifices adapted to the diameters of evaporating-dishes or plates. In the British Pharmacopceia when, a wafer-bath is directed to be used, it is to he understood that this term refers to an apparatus bj means of which water or its vapor at a temperature not exceeding 2120, is applied to the outer surface of a vessel containing the substance to be heated, which substance may thus be subjected to a heat near to, but necessarily below, that of 212°. In the steam-bath the vapor of water at a temperature above 212°, but not exceeding 230", is similarly applied."
Platrrmm residues should be preserved, and the metal recovered from tliem from tune to time (vide p. 203).
Hot alcohol sometimes reduces perchloride of platinum, the mefal being thrown out of solution in a finely divided form, known as plati- num, black; only aqueous solutions, therefore, of the salt should be used where heat is employed. Hence, also, in washing out excess of perchloride of platinum from the double chloride of platinum and potassium by spirit, the Bjopllcation of heat should be avoided.
S^ervesdng Potash- Water {Liquor Potassce Effervescms, B.F.) is most easily estimated volumetrically (p. 441). Any adulteration by an equivalent amount of bicarbonate of sodium would, however, by that process be undetected ; hence the Pharmacopceia directs that " five fiuidouuces, evaporated to one-flfth and 12 grains of tar- taric acid added, yield a crystalline precipitate, which, when dried, weighs not less than 12 grains." Five fluidounces of this prepara- tion should contain 7.5 grains of bicarbonate, convertible into 14,1 grains of acid tartrate of potassium by 11.25 grains of tartaric acid. Tliemethodissomewhatrough, but quite efficient for "potash-water" containing nothing but bicarbonate of potassium.
id .y Google
STIMATION OF SODIUM. 4G1
Proportional weights of equivalent quantities of potassium and Us salts.
Metal K^ ...... . 78
Oxide (" Potash ") . . . K,0 94
Hydrate (" Caustic Potash") 2KH0 112
Carbonate (Anhydrous) . K^CO, .... 138
Carbonate (Crystalliae) . . K,C0„ + 16% aq. . 164.286
Bicarbonate aKHCO, .... 200
Nitrate 2KJs'0, .... 202
Platinum salt PtCI„2KCI. . . 489
SODIITM.
Sodium is usually estimated as sulphate. Accuratiily weigh a porcelain crucible and lid, place within about -S of pure rock-salt, and again weigh, making a memorandum of the weights in a note-book. Add rather more strong sulphuric acid than maybe considered sufQcient to conveit the chloride into acid sulphate of sodium. Heat the cru- cible gradually, the flame being first directed against the side of the crucible to avoid violent ebullition, until fumes of sulphuric ^cid cease to be evolved, towards the end of the operation dropping in one or two fragments of carbonate of ammonium to facilitate complete decomposition. 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 chloride of sodium employed.
2IiaCl + H,SO. = Na,SO, + 2IIC1. in 142
Proportional weights of eqitiualent quantities of sodium and its salts.
Metal Na,
Oxide ("soda") Na^O . . . .
Hydrate (" caustic soda") . . . 2NaH0 . . .
Carbonate (anhydrous) .... Na^COj . . .
Carbonate (crystals) JJa,CO,,10HjO .
Bicarbonate 2NaHC0, . .
Chloride 2NaCl . . .
Sulphate (anhydrous) .... Na^SO. . . .
Sulphate (crystals) Na.SO„10H,O.
39*
id .y Google
AMMONITJM.
Salts of ammonium are, for purposes of quantitative analysis, generally converted into the double chloride of ammonium and platinum (PtClj2NH,CI), the details of manipulation being the same as tihose observed in the case of potassium. About 0.15 grm. of pure, white, dry chlo- ride of ammonium may be taken for experiment.
COMPOSITION
Cl„ . . . 35.5 X 6
4-t7 100.00
The proportion of nitrogen, ammoninm, or chloride of ammonium in the double chloride may also.be ascertained from the weight of platinum left on igniting the double chloride; for this purpose heat must be applied slowly, or platinum will be mechanically cwried off with the gas- eous products of decomposition.
Proportional weights of equivalent quantities of ammonia cal compounds.
Ammonia (gas) 2NH, . . .
Ammonium (NH,)^? . .
Chloride of ammonium . . . 2NH,C1 . .
Platinum salt PtCI„3NH.Cl
"Carbonate of ammonium" . (N,II,„C,OJ -H Sulphate of ammonium . . (KHJ^SO^
BARITJM.
Barium is estimated in the form of anhydrous sulphate of barium (BaSOJ.
Process. — Dissolve 0.3 or 0.4 of pure crystallized and dried chloride or nitrate of barium in about half a litre of water in a beaker, heating to incipient ebullition, and
id .y Google
HEAVI METRIC ESTIMATION OP BARIUM. 463
slightly acidulating with hydrochloric or nitric acid. Add diluted sulphuric acid (prepared some days previously, so that sulphate of lead may have deposited) so loiig as a precipitate forms, keep the mixture hot for some time, set aside for half an hour, pass the supernatant liquid through a filter, gently boil the residue two or three times with more water; finally collect the precipitate on the filter, removing adherent particles from tlie bealier by the finger, and cleansing by a stream of hot water from the wash- bottie. The precipitate must be washed with hot water until the filtrate ceases to turn litmus paper red, or give any cloudiness when tested with chloride of barium. The filter and sulphate of barium, having thoroughly drained, is dried in a warm place, commonly by supporting the funnel in an inverted bottomless beaker over a sand-bath or hot plate.
The sulphate of barium is now removed from the filter, heated to drive off every trace of moisture, and weighed. This is accomplished by placing a weighed porcelain cru- cible (and cover) 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 detached powder dropped into the crucible, the paper folde I encased in two or three coils of one end of a plati- nu w re and burnt over the crucible, ash and any particles in the si eet of paper dropped into the sulphate of barium, t! e oi en crucible exposed over a flame till its contents afc {u te white, covered, cooled, and weighed.
Chloride of barium BaCl^ - -
Nitrate of barium Ba^NOj .
Sulphate of barium BaSO, . .
Composition of Sulphate of Barium,.
In these experiments it is unnecessary to take filter-ash into accouut. Faults of manipulation cause far greater errors.
id .y Google
CALCIUM,
Colcinrn is usually thrown out of solution in the form of oxalsite, tlie precipitate ignited, and tlio resulting carbon- ate weighed.
Process. — Dissolve 0.3 or 0.4 of dried colorless crystals of ealc-spar iu about a third of a litre of water acidulated with hydrochloric acid, heat the solution to near the boil- ing-point, add excess of sohition of oxalate of ammonia, then ammonia until, after stirring, the liquid smells strongly Rnimoniacal; set aside iu a warm place for twelve hours. Carefully pour off the supernatant liquid, passing it through a filter ; add hot water to the precipitate, set aside for half an hour, again decant, and, after once more washing, trans- fer the precipitate to the filter, allowing all contained fluid to pass through before a fresh portion is added. Wash the precipitate with hot water, avoiding a rapid stream, or the precipitate may be driven through the pores of the paper. Dry, transfer to a weighed crucible, and incinerate, as described for sulphate of barium, and slowly heat the precipitate till 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 lamp, cool, and weigh.
The resulting carbonate of calcium should have the same weight as the calc-spar from which it was obtained. If loss has occurred, carbonic acid gas has probably escaped. In that case moisten the residue with water, and after a few minutes test the liquid with red litmus or tui-meric paper ; if an alkaline reaction is noticed, it is dne to the Ijresence of caustic lime. Add a small lump of carbonate of ammonium, evaporate to dryness over a water-bath, and again ignite, this time being careful not to go beyond the prescribed temperature. The treatment may, if necessary, be repeated.
Proportional weights of equivalent quantities of calcium salts.
Oxide (quicklime) CaO . . .
Hydi-ate (slaked) lime Ca2nO . .
Carbonate CaCO, . .
Sulphate (anhydrous) CaSO, . .
Sulphate (crystalline or precipit'd) CaSO,, 2H0
Chloride CaCl . .
Phosphate (of bone) (Ca,3PO,)310
Superphosphate CaH^SPO, .
id .y Google
MAGNESIUM.
Process 1. — The light or heavy carbonate o/ magnesmm of pharmacy may be estimated by heating a weighed quan- tity to redness in a porcelain crucible. If it has the com- position indicated by the formula given in the British Pharmacopaeia (3MgC0,, Mg2H0, 4H^0), it will yield 43 per cent, of magnesia (MgO). According to that work, the purity of even sulphate of magnesium (MgSO^, THjO) may be determined by boiling a weighed quantity with excess of carbonate of sodium, collecting the precipitate, washing, drying, igniting, and weighing the resulting mag- nesia (MgO), The crystallized sulphate should afford 16.26 per cent, of oxide. The official solution of carbonate of magnesium in carbonic acid water {Liquor Magnesia Garbonatis, B. P.) should yield five grains of pure oxide of magnesium per fluidounce.
Process 3. — The general form in which magnesium is precipitated is as phosphate of ammonium and magnesium (MgNH^PO,, 6HjO); this, by heat, is converted into pyro- phosphate of magnesium (Mg^PaO,). Accurately weigh a small quantity (0.4 to 0.5) of pure dry crystals of sulphate of magnesium, dissolve in two or three hundred cubic centimetres of cold water in a beaker, add chloride of am- monium, ammonia, and phosphate of sodium or ammo- nium, agitate with a glass rod (without touching the sides of the vessel, or crystals will firmly adhere to the rubbed portions), and set aside for twelve hours. Collect on a filter, wash the precipitate with water containing a tenth of its volume of the strongest solution of ammonia, until the filtrate ceases to give a precipitate with an acidulated solution of nitrate silver. Dry, transfer to a crucible, burn the filter in the usual way, heat slowly to redness, cool, and
Proportional weights of equivalent quantities of magnesium salts.
Pyrophosphate . . Mg,,P,0, 223
Sulphate .... 2{MgS0,,1H,0) 493
Oxide 2(M;rO) 80
Official carbonate . {3MgC0^, Mg3II0, 411^0)^2 . 191
id .y Google
QUANTITATIVE ANA
ZINC.
Zinc is usually estimated as oxide (ZnO), occasionally as sulphide (ZnS).
Process, — Dissolve a weighed quantity (0.5 to 0.6) of sulphate of zinc in about half a litre of water in a beaker, heat to neai" the boiling-point, add carbonate of sodium in slight excess, boil, set aside for a short time ; pass the supernatant liquid through a filter, gently boil the precipi- tate with more water, again decant ; repeat these opera- tions two or three times ; collect the precipitate on the filter, wash, dry, transfer to a crucible, incinerate, ignite, cool, and weigh. 281 (=molec. weight) of sulphate should yield 81 (=mole(!, weight) of oxide.
ALUMIBITTM.
Aluminium is always precipitated as hydrate (Al^GIIO) and weighed as oxide (AljO,).
Process. — Dissolve about two grammes of pure dry am- monium-alum in half a litre of water, heat the solution, add chloride of ammonium and a slight excess of ammonia, boil gently till the odor of ammonia has nearly disap- peared, set aside for the hydrate to deposit, pass the supernatant liquid through a filter, wash the precipitate three or four times by decantation, transfer to the filter, finish the washing, dry, burn the filter, ignite in a covered crucible, and weigh.
A1.,3S0„{NH,),S0,, 2411^0 907
Ai,0, 103
Per cent, of Al^O^ yielded by animonium-ahira . 11.356
QUESTIONS AND EXERCISES.
993. Give details of the manipulations obseryed in graviroetrically estimatinff salts of potassium or ammonium.
994. What quantity of chloride of sodium is contained in a sample of rock-salt 0.351 gramme of which yields 0.44 of sulphate of sodium ? — Ans. 100 per cent. (It is absolutely pure.)
995. To what amount of the official alum is 0.894 of a gramme of the double chloride of platinum and ammonium equivalent? — Ans. 1.814 gramme.
996. Find the weight of sulphate of barium obtainable from 0.522 of nitrate.— -4)is. 0.46G.
id .y Google
GEAVIMETRIO ESTIMATION OE IRON. i^l
997. Describe the usual method by ^i-hioh salts of calcium are estimated.
998. By what quantitative processes may the official salts of mag- nesium be analyzed?
999. Calculate the jiroportion of pure sulphate of ainc in a sample of crystals 0.574 of which yield 0.161 of oxide.— .d«^. 99.3 per eeiit.
1000. Ascertain the weight of alumina (ALOj) which should be obtained from 1.814 gramme of ammonium-alum.
lEON,
Iron and its salts are gravi metrically estimated in the form of feme oxide (Pe^O,).
Compounds containing organic acidulous radicals are simply incinerated, and the resnlting oxide weighed. Thus 1 gramme of the offlcial citrate of iron and ammoninm {Ferri et Ammoniee C'ifras, B. P.) incinerated, with expo- sure to air, leaves not less than .St of ferric oxide. A small quantity of the salt is weighed in a tared covered porcelain crucible, flame cautiously applied until vapors cease to be evolved, the lid then removed, the crucible slightly inclined and exposed to a red heat until all carbonaceous matter has disappeared. The residual ferric oxide is then weighed. The tartrate of potassium and iron {Ferrttm Tartaratum, B. P.) is treated in the same manner, except that the ash must be washed and again heated before weighing, in order to remove carbonate of potassium produced during incine- ration ; 5 grammes should yield 1.5 gramme of ferric oxide.
From, other compounds of iron, soluble in water or acid, the metal is precipitated in the form of hydrate (Fe^SHO) by solution of ammonia, and converted into oxide {Fe,Oj) by ignition. Dissolve a piece (about 0.2) of the purest iron obtainable (piano wire), accurately weighed, in water acidulated with hydrochloric acid; add a few drops of nitric acid and gently boil; pour in excess of ammonia, stir, set aside till the ferric hydrate has deposited, pass the supernatant liquid through a filter, treat the precipitate three or four times with boiling water; transfer to the filter, wash till the filtrate yields no trace of chlorine (for cliloride of ammonium will decompose ignited ferric oxide, with volatilization of ferric chloride), dry and ignite as usual, and weigh. Iron in the official solutions {Liquor Ferri Perchloridi Fortior, Liquor Ferri Pernitratis, and Liquor Ferri Persulphatis) may be estimated by this general process.
id .y Google
468 QUANTITATIVE ANALYSIS.
The proportion ofmelallic iron in a mixture of iron and osidea of iron may be determined by digestion in a strong solution of iodine in iodide of potassium, which attaclcs the metal only. The reduced iron of pliarmauy {Ferrum, Eedactum) is in good condition so long as it contains, as shown by this method, half its weight of free metal.
Proportional weights of equivalent quantities of iron and its salla.
Metal .... Ferric oxide . . Ferric hydrate . Ferric chloride . Ferric snlphate . Ferrous sulphate
. Fe, 112
. Fe,0, 160
. Fe,6H0 214
. Fe,Cl 325
. Fe,3S0. 400
. 2(FeS0„ 111,0). . . 556
AESENICUM.
Arsenic (As^OJ is usually estimated volumetnoally (vide p. 449), With certain precautions arsenicum may also be precipitated and weighed as sulphide (ASaS,).
Process, — The pure, white, massive arsenic (about 0.2) is dissolved in a flask in a small quantity of water contain- ing bicarbonate of sodium or potassium, tlie liquid being heated. A slight excess of hydrochloric acid is then added, and sulphuretted hydrogen gas passed through the solu- tion so long as a pi-ecipitate falls, the mouth of the flask being stopped by a plug of cotton-wool (to prevent undue access of air and consequent decomposition of the gas, resulting in precipitation of sulphur). Warm the mixture in the flask and pass carbonic acid gas through it until the odor of sulphuretted hydrogen has nearly disappeared. Collect the precipitate on a tared filter, wasli as quickly as possible with hot water containing a little sulphuretted hydrogen, dry in a water-oven and weigh. 198 parts of arsenic should yield 246 of sulpliide of arsenicum.
AHTIMOHY.
The metal is precipitated in the form of sulphide (Sb^SJ, with the precautions observed in estimating arsenicum — a small quantity of tartaric acid, as well as hydrocliloric, being added, to prevent the precipitation of an oxysalt. The experiment may be performed on about half a gramme of pure tailar-emetic ; the salt should yield nearly half its
id .y Google
COPPER — BISMUTH. 463
weight (49.56 per cent.) of siiljihide. According to Fre- senius, the eulphide dried at 100° C. still contains 2 per cent, of water, and must be lieated, in a current of carbonic acid gas, until it turns from an orange to a black color, before all moisture is expelled. In the British Pharmaeo- pceia the purity of tartar-emetic {Antimonium, Tarlaralwm), and the strength of solution of chloride of antimony (it. quor Antimomi CMoridi), are determined bj' the above process.
COPPER.
Copper is precipitated from its solutions and weighed either (1) as metal (CuJ, or (3) as oxide (CuO).
Procesa 1. — Dissolve about half a gramme of dry crystal- lized sulphate of copper in a small quantity of water, in a tared porcelain crucible or beaker, acidulate with hydro- chloric acid, introduce a IVagmeut or two of pure zinc, cover the vessel with a watch-glass, and set aside till evo- lution of hydrogen 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 drained, riiiaed with strong spirit of wine, dried in the water-oven, and weighed.
Process 2. — Aboutthree-fourthsof a gramme of sulphate of copper is accurately weighed, dissolved in half a litre of water, the liquid boiled; dilute solution of potash or soda is then added till no more precipitate falls, ebullition con- tinued for a short time, and the beaker set aside ; the supei*- nat&nt liquid is decanted, the precipitate boiled with water twice or thrice, collected on a filter, washed, dried, trans- ferred to a crucible, the filter incinerated, and its ash moist- ened with a drop of nitric acid ; the whole is finally heated strongly, cooled, and weighed.
249.5 parts of sulphate of copper yield T!l.5 of oxide, or 63.5 of metal.
BISMUTH.
Dissolve 0.3 or 0,4 of pure oxycarbonate of bismuth (2Bi,0jC0^, H,0) {BismutU Carbonaa, B. P.) in a small quantity of hydrochloric acid, dilute with water slightly acidulated by hydrochloric acid, pass excess of sulphuret- ted hydrogen through the liquid, collect the precipitate on a tared filter, wash, dry at 100° C, and weigh. The sul- 40
id .y Google
iln QUANTITATIVE ANALYSIS.
phide must not be exposed too long in the water-oven, or it will increase in weight owing to absorption of oxygen ; henue it should be tested in the balance every half-hour during desiccation. 517 of oxycarbonate should yield 512 of sulphide (Bi^Sj), The strength of the official solution of citrate of bismuth and ammonium (Liquor Bismuthi et Ammoniee Gitratis, B. P.) is determined by this process. "Three fluidrachms of the solution, mixed with an ounce of distilled water, and treated with sulphuretted hydrogen in excess, yield a black precipitate, which, collected, washed, and dried, weighs 9.92 grains. One fluidrachm yields three grains of oxide of bismuth." The atomic weight of bis- muth is 208.
MEECUEY.
This clement may be (1) isolated and estimated in the form of metal, or precipitated and weighed as (2) mercu- rous chloride, or (3) mercuric sulphide.
Process 1. — The process by which the metal itself is separated is one of distillation, into a bulb surrounded by water. About half a metre of the difficultly fusible Ger- man glass known as combustion-tubing is sealed at one end after the manner of a test-tube ; a mixture of bicar- bonate of sodium and dry chalk is then dropped into the tube to the height of two or three centimetres, and, next, several small fragments of quicklime so as to occupy another centimetre ; 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-rinsings of the mixing-mortar, alayor of a few centimetres of powdered quicklime, and iinally a plug of asbeitos (a fibrous mineral unaflected by heat). The whole powder should occupy two-thirds of the length of the tube. The part of the tube just above the asbestos is now softened in the blowpipe-flame and drawn out about a decimetre to the diameter of a narrow quill ; it is again drawn out to the same extent at a point about two or three centimetres nearer the mouth, 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 nearly to a right angle ; the tube is then softened close to the bulb and slightly bent so that the bulb may be parallel with the large tube; then softened on the other side of the
id .y Google
OaAV! METRIC EfiTJMATION OF LEAD. 411
bulb, and the narrow terminal tnbe bent to a right anglo, so that, the tube being held in a horizontal position, the bulb maybe sunk in water, and the terminal tube point upwards. The long tube is now laid in the gas-furnace found in most laboratories, a basin so placed that the bulb of the apparatus may be cooled by being surrounded by water, the part of the tube occupied by asbestos heated to redness, and the flame slowly lengthened until the whole tube is red-hot. Under these circumstances the mercurial compound volatilizes, is decomposed by the lime, and its acidulous radical lixed, the mercury carried in vapor to and condensed in the bulb, the carbonic acid gas evolved from the bicarbonate of sodium and chalk washing out the last portions of mercury-vapor from the tube. When the distillation is considered to be complete, the diah of water is removed, the bulb dried, and then detached by help of a file at a point beyond any sublimate of merouvy. The bulb is lastly weighed, the mercury shaken, or die- solved out, and the tube again dried and weighed.
Process 2. — The process by which mercury is separated in the form of calomel, consists in adding hydrochloric and phosphorous acids (uirfe p. 289) 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 100° C, and weighing (Rose), The experiment may be tried on half a gramme, to a gramme, of corrosive sublimate.
Process 3. — Two or three decigrammes of corrosive subli- mate are dissolved in water, the solution acidulated with hydrochloric acid, excess of sulphuretted hydrogen passed, the precipitate collected on a tared filter, washed with cold water, dried at 100° C, and weighed,
Proportional weights of equivalent quantities of mercury and its salts.
Metal Hg , . , . 200
Mercurous chloride . . HgCl . , . 235.5 Mercuric chloride . . . HgCl^ . , , 211 Mercuric sulphide . . HgS . . , . 232
LEAB.
Lead is generally estimated either as (1) oxide, (2) sul- phate, or (3) chromate.
Process 1, — Weigh out one or two grammes of pure
id .y Google
412 QUANTITATIVE ANALYSIS.
acetate of lead in a covered crucible, previously tared, and heat slowly until no more vapora are evolved. Remove the lid, stir down the carbonaceous mass with a clean iron ■wire, and keep the crucible in the flame ao long as any car- bon remains nnconsumed. Introduce some fragments of fused nitrate of ammonium, 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 of a gramme of acetate of lead in a small quantity of water, drop in diluted sulphuric acid, add to the mixture twice its bulk of methylated spirit of wine, and set aside. Decant the supernatant liquid, col- lect the sulphate on a filter, wash with spirit, dry, transfer to a porcelain crucible, removing as much of the sulphate as possible from the paper, incinerate on the crucible-lid (not in a platinum coil, for the particles of reduced lead would unite with the platinum by fusion), ignite, cool, and weigh.
Frocess 3, — About half a gramme of acetate of lead is dissolved in two or three hundred c. c. of water, acetic acid added, and then solution of red chromate of potassium. Collect the precipitate on a tared filter, wash, dry at 100*^ C, and weigh.
Molecular weights of salts of lead.
Metal . . . Pb SOT
Acetate . . Pb3C,H,0., 3H,0 . 379
Oxide . . . PbO 223
Sulphate . . PbSO. nOB
Chromate . . PbCrO, .... 323.5
SILVEE.
Compounds of silver which are readily decomposed by heat are estimated in the form of (1) metal, others usually as (2) chloride (AgCl), but sometimes as (3) cyanide (AgNC).
Process 1. — Heataboutagrammeof oxideof silver (Ag^O) in a tared crucible, cool, and weigh. 332 of oxide yield 216 of metal. " 29 grains heated to redness yield 27 grains of metallic silver." — Brif-. Pharvi.
Process 2. — Dissolve 0.4 or 0.5 of pure dry crystals of nitrate of silver in water, acidulate with two or three drops of nitric acid, slowly add hydrochloric acid, stirring rap- idly, nnti! no more precipitate falls. Pour off the super- natant liquid through a filter, wash the chloride of silver
id .y Google
Ci;PF, LI.ATION. 473
onec or twice with hot water, transfer to the iiUer, com- plete the washing, and dry. After removing as iituch &b possible of the precipitate from the paper to the crucible, burn the filter, letting its ash fail on the inverted lid of the crucible, moisten with a drop of nitric acid, warm, add a drop of hydrochloric acid, evaporate to dryness, replace the lid on the crucible, ignite the whole until the edges of the mass of chloride begin to fuse; cool, and weigh. 110 of nitrate yield 143.5 of chloride. According to the British Pharniacopccia, 10 parts of nitrate should thus yield 8.44 of chloride, and the filtrate from the chloride evaporated to dryness should leave no residue, indicating absence of nitrates of potassium or sodium and other sim- ilar adulterants.
P»-ocess 3. — Cyanide of silver may be collected on a tared filter and dried at 100° C. 110 of nitrate yield 134 of cyanide.
Silver and its salts may be volu metrically estimated by a Standard solution of chloride of sodium.
CupellaHon. — The amount of silver in an alloy may he also deter- mined by a dry method. The metal is folded in a piece of thin sheet lead, placed on a cupel [cupella, little cup, made of compressed bone- earth) and heated in a furnace, the cupel bein^ protected from the direct action of flame by a muff-shaped, or, rather, oven-shaped case termed a muffle. The metals melt, the baser become osidized, the oside of lead fusing and dissolving the other o:<idcs ; the fluid o.\id^ are absorbed by the porous cupel, a button of pare silver remaining. An alloy suspected to contain 95 per cent, of silver requires about 3 times its weight of lead for successful cupellation ; if 92 J per cent. (English silver coin), between 5 and 6 times as much lead is necessary.
QUESTIONS AND EXERCISES.
1001. Esplain the gravimetric process by which the strength of the official solutions of ferric chloride, nitrate, and sulphate ai'C de- termined.
1002. Mention tho various amounts of ferrous and ferric aalta equivalent to 100 parts of metal.
1003. State the precautions necessary to be observed in estimating arsenicum or antimony in the form of sulphide.
1004 In what form are the official compounds of bismuth weighed for quantitative purposes !
1005. Give an outline of the process by which mercury may be isolated ftom its official pceporatioas and weighed in the metallic condition.
1006. Describe three methods for the quantitative analysis of salts
40*
id .y Google
4T4 QUANTITATIVE ANALYSIS.
of lead; and the weights of the respective precipitates, supposing 0.56 of crystallized acetate to have been operated on in each ease.
1007. Describe the processes by which silver is estimated in the forms of metal, chloride, and cyanide.
1008. What proportions of nitrate of silver are indicated, respec- tively, by 15 01 metal, 9.8 of chloride, and 8.1 of cyanide?
1009. Define cupellation.
ESTIMATION OF THE ACIDULOUS KADICALS OF SALTS.
CHLORIDES.
Free chlorine (chlorine- water) and oompoiinds which hy action of acids yield free chlorine (Chlorinated Lime, Chlo- rinated Soda, and their oflieial Solutions) are estimated volu metrically by a standard solution of hyposulphite of sodium (vide p. 453). The amount of combined chlorine in pure chlorides (HCl, NaCl) may also be determined by volumetric analysis with a standard solution of nitrate of silver (p. 447),
Combined chlorine is gr a vi metrically estimated in the form of chloride of silver, the operations being identical with that just described for silver salts ; 58.5 parts of pure, colorless, crystallized chloride of sodium (rock-salt) yield 143.5 of chloride of silver.
IODIDES.
Free iodine is estimated volumetricallj' by sohition of hyposulphite of sodium {vide p. 453).
ComHned iodine is determined gravimetrically in the form of iodide of silver, the operations being conducted as with chloride of silver. Iodide of potassium may be used for an experimental determination: KI=I66 should yield Agl=235. Of the ofHcial iodide of cadmium {Oadmii lodidum, B. P.) it is stated that " ten grains dissolved in water, and nitrate of silver added in excess, give a pre- cipitate which, when washed with water and afterwards with half an ounce of solution of ammonia, and dried, weighs 12.5 grains."
In presence of chlorides and bromides the iodine in iodides may be precipitated and weighed as iodide of palladium.
id .y Google
BROMIDES — CYANIDE
BROMIDES.
Free bromine may be estimated by shaking with excess of solntioii of iodide of potassimn, and then determiniEg the equivalent quantity of liberated iodine by a standard solution of hyposulphite of sodium (p. 453),
The bromine in bromides may be precipitated and weigfied as bromide of silver, the manipulations being the same as those for chloride of silver: 0.2 to 0.3 of pure bromide of potassium may be used for an experimental analysis.
CTAKIDES.
The hydrogen cyanide (hydroeyanie aeid) is usually estimated volu metrically (vide p. 441).
From all soluble cyanides, cyanogen may be precipitated by nitrate of silver, after acidulating with nitric acid, the cyanide of silver collected on a tared filter, dried at 100° C, and weighed.
Of the official Diluted Hydrocyanic Acid, it is stated that one hundred grains (or 110 minims) precipitated by solution of nitrate of silver yield ten grains of dry cyanide of silver.
Cyanide of Silver.
Sih-ei Cyan.
HITEATES.
Nitrate cannot be estimated by direct gravimetric ana- lysis, none of the basylous radicals yielding a definite nitrate insoluble in water. With some difficulty they may be determined by indirect volumetric methods.
Process. — The beet method is that by Crum, as modified by Frankland and Armstrong, It consists in agitating with mercury a concentrated solution of the nitrate with a large excess of concentrated sulphuric acid — the whole of the nitrogen being then involved as nitric oxide. From the volume of the latter the weight of nitrate whence obtained is easily calculated. No chlorides must be present. For educational purposes the experiment may be conducted on 3 or 4 c. c. of a solution of one gramme of pure nitrate of
id .y Google
47G QUANTITATIVE ANA!.VSia.
potassium in 100 c. c, of distilled water. From I to 10 c. c. of such a solution will very well represent the nitrates in half a litre of well-water.
The following is the mode in which this process is ap- plied to the estimation of nitrogen existing as nitrates and nitrites in potable waters. The solid residue from hilf a litre of water used for determination of total =iolid constituents* is treated with a small quantity of distilled water, a very slight excess of sulphate of silver is added to convert the chlorides present into sulphates, and the filtered liquid is then con- centrated by evaporation in a small beaker until it IS leduced in bulk to two or three cubic centime- ties The liquid must now be transferred to a glass tube (about as long as the hand) (see fig.) pre- ^ lously filled with mercury at the mercurial trough, 11 "ind furnished at its upper extremity w^ith a cup ''' ind stopcock, the beaker being rinsed out once or twice with a very small volume of recently boiled distilled water, and finally with pure and concen- tiated sulphuric acid in somewhat greater volume than that of the concentrated solution and rinsings. Ifl I (Poi a method of purifying the acid vide p. 392.) By a little dexterity it is easy to introduce suc- cessively the concentrated liquid, rinsings, and sulphuric acid by means of the cup and stopcock, without the admission of any trace of air. Should, however, air inadvertently gain admittance, it is readily removed by depressing the tube in the mercury trough, and then momentarily opening the stopcock. If this be done within a minute or two after the introduction of the sulphuric acid, no fear need be entertained of the loss of nitric oxide, as the evolution of this gas does not begin until a minute or so after the violent agitation of the contents of the tube.
The acid mixture being thus introduced, the lower ex- tremity of the tube is to be firmly closed by the thumb, and the contents violently agitated hj' a simultaneous vertical
* If the irater contaiu nitratea, a separate half litre should lie taken for tills deterni illation, otherwise there is a risk of loss of nitro- gen daring evaporatioil. The nitrites In this lialf litre of water must be transformed Into nitrates by the cantious adttltioii of potasi<lc permangaimte to the si igbtly acidified water before the evaporation U commenced. Immediately after the action of the penuangauata the water must be again rendered eiightly allcaline.
id .y Google
NITRATES. 4.TI
aiitl lateral movement, in. such a manner that there is alwaj'S an unbroken column of mercury, at least an inch long, at the bottom part of the glass tube. From the description, this manipulation may appear diffloult; but in practice it is extremely simple, the acid liquid never coming in contact ■with the flesh. In about a minute from the commencement of the agitation a strong pressure begins to be felt against the thumb of the operator, and mercury spurts out in mi- nute streams, as nitric oxide gas is evolved. The escape of the metal should be gently resisted, so as to maintain a considerable excess of pressure inside the tube, and thus prevent the possibility of air gaining access to the interior during the shaking. In from three to five minutes the reaction is completed, and the nitric oxide may then be transferred to a suitable measuring-apparatus, where its volume is to he determined over mercury. As half a litre of water is used for the determination, and as nitric oxide occupies exactly double the volume of the nitrogen which it contains, the volume of nitric oxide read off expresses the volume of nitrogen existing as nitrates and nitrites in one litre of the water. From the number so obtained, the weight of nitrogen in these forms in 100,000 parts of water is easily calculated. (1 litre of H weighs .0896, and N is 14 times as heavy as H; 101 of KNOj contains 14 of N.)
SULPHIDES.
Process 1. — Soluble sulphides (H^S, NaHS, e. g.) may be determined volumetric ally by adding to the aqueous liquid a measured excess of an alkaline solution of arsenic of known strength, neutralizing by hydrochloric acid, diluting to any given volume, filtering off the sulphide of arsenicum precipitated, taking a portion of the filtrate eqaal to half or a third of the original volume, and, after neutralizing by acid carbonate of sodium, estimating the residual arse- nic by the standard iodine solution (vide p. 448). The process may be tried on a measured volume of sulphuretted hydrogen (the weight of which is easily calculated ; 1 litre of hydrogen = 0,0896 gramme) absorbed by a strong so- lution of soda or potash.
Process 2. — Sulphur and sulphides may also be quanti- tatively analyzed by oxidizing to sulphuric acid and pre- cipitating in the form of sulphate of barium. A couple of decigrammes of a pure metallic sulphide may be decom- posed by careful deflagration with a mixture of chlorate
id .y Google
418
QUA
of potassium and carbonate of sodium, the product dis- solved in water, acidulated witd hydrochloric acid, solution of chloride of barium added, and the precipitated sulphate of barium purified aud collected as described in connection ■with the estimation of barium (p. ifi2). Many sulphides may be oxidized in a flaak by chlorate of potassium and hydrochloric acid, and then precipitated by chloride of barium. Experimental determinations may also be made on a weighed fragment of sulphur, about 0.1, cautiously fused with a solid caustic alkali, and the product oxidized while hot by the slow addition of powdered nitrate or chlorate of potassium, or, wlien cold, by treatment with chlomte of potassium and hydrochloric acid, and subse- quent precipitation by chloride of barium.
Note. — Fusions performed by help of a gas-lamp must be care- fully oondnct«d; for any alliali that may creep over the side of a crucible will certainly absorb aulphurons acid from the products of combustion of the gas, and error result.
Process 3. — Soluble sulphides may also be treated with excess of an alkaline arseniate, arsenious sulphide be then precipitated by the addition of hydrochloric acid, and the precipitate collected and weighed with the usual precau- tions {vide p. 468).
Weighis of equioalenl quantities of sulph compounds.
Sulphur S ...
Sulphuretted hydrogen . . H^S . . Sulphate of barium . . . BaSOj Arsenious sulphide . . . (As^SJ-^S
Iron pyrites (FeS,)-^2
Galena PbS . .
f and Us
SULPHITES.
Sulphites are usually estimated volumetrically by a standard solution of iodine (vide p. 448), Sulphites insolu- ble in water are diffused in that menstruum, hydrochloric acid added, and the iodine solution then dropped in.
If necessary, sulphites may be estimated gravimetri- cally by oxidation and precipitation in the form of sulphate of barium.
id .y Google
SULPHATES — CARBONATE
STTLPHATES.
These salts are always precipitated and iveiglied aa sul- phate of barium, the manipulations being ideutical with those ijerformed in the determination of barium by means of sulphates (vide p. 462). The purity of Sulphate of Sodium (Sodx Sulphas, B. P.), and the presence of not more than a given amount of sulphuric acid in Tinegar (Acetum, B. P.),are directed, in the British Pliarmacopreia, to be ascertained by this process. Five ounces of vinegar should yield not more than about one-third of a gramme of sulphate of barium.
Proportional loeights of equivalent quanliUes of sulphates.
The sulphui'ic radical . , . SO, 96
Sulphuric acid H,SO, .... 98
Sulphate of barium .... BaSO, .... 233
CAEBONATES.
Carbonates are usually estimated by the loss in weight they undergo on the addition of a strong acid.
Process 1. — A small light iiask 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 a cork; the one straight, extending from about two or three centimetres above the cork to the bottom of the flask ; the other cat off close to the cork on the inside and curved outwards so as to carry a thin drying-tube horizontally above the flask. The drying-tube may be a short narrow test-tube, the bottom of which is constricted so as to form a narrow tube open at the end ; it is nearly filled with small pieces of chloride of calcium, a plug of cotton-wool preventing escape of any fragments at either end, and is attached by a pierced cork to the free extremity of the curved tube of 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 by 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 JVag- ment of cork or wax, and the whole weighed. The appa- ratus is then inclined so that the oil of vitriol and carbon- ate may slowly react ; carbonic acid gas is evolved and
id .y Google
480 QUANTITATIVE A.VALYBIS.
escapes through the iiorizoiital tube, an}' moisture being retained by tlie chloride of ealcinm. When effervescence has ceased, the gas still remaining in the vessel is sucked oat ; this is accomplished by adapting 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. If the heat pro- duced by the action of the oil of vitriol and solution is considered insufficient to expel all the carbonic acid from theliquid,theplugisagaininsertedin the tube and the con- tents of the flask gently boiled for some seconds. When th3 apparatus is cold, more air is again drawn through it, and tlie whole finally weighed. The loss is due to carbonic acid gas (COj), from the weight of which that of any car- bonate is ascertained by calculation. Carbonates insoluble in water may be attacked by hydrochloric instead of sul- phuric acid; granulated mixtures of carbonates and pow- dered tartaric or citric acids by inclosing the preparation in the inner tube and placing water in the Sask, or vice versd. The apparatus also may be modified in many ways to suit the requirements, convenience, or taste of the ope- rator.
Process 2, — Carbonates from which carbonic acid gas is evolved by heat may be estimated by the loss they expe- rience on ignition.
Proceae 3. — Free carbonic acid gas may be absorbed by a solid stick of potash or a strong alkaline solution, the loss in volume of the gas or mixture of gases indicating the amount originally present.
Weights of equivalent quantities of carbonic acid gas and certain carbonates.
Carbonic acid gas CO . ^'-^
Carbonic acid II,CO.,
Anhydrous carbonate of sodium . . Na CO,
Anhydrous carbonate of potassium . K^COj
Carbonate of calcium CaCO^
OXALATES.
Process 1. — The oxalic radical is usually precipitated in the form of oxalate of calcium, and weighed as carbonate, the manipulations being identical with those observed in the estimation of calcium (vide p. 464). The experiment may be performed on 0.3 or 0.4 of pure crystallized oxalic
id .y Google
PUOSPH ATES. 4SI
acid, 136 parts of which should yield 100 of carbonate of calciuiH.
Process 2. — Oxalates may also be determined by conver- sion of their acidulous radical into carbonic aeid gas, and observation of the weight of the latter. The oxalate, water, and excess of blaek oxide of manganese are placed in the carbonic acid apparatus, a tube full of oi! of vitriol lowered into the flask, the whole weighed, and the opera- tion completed as for carlionates. From the following equation it will be seen that every 88 parts of carbonic acid gas evolved indicate the presence of 126 parts of crystallized oxalic acid or an equivalent quantity of other oxalate : —
Na,CA + MnO, + 2H,S0, = MnSO. + Na.SO, -f- 2H,0 + 2C0,.
The black oxide of manganese used in this experiment must be free from carbonates. The amount of materials employed is regulated by the size of the vessels.
PHOSPHATES.
Profess 1. — From, phosphates dissolved in water, the 2>hosphoric radical may be precipitated and weighed in the foini of pyrophosphate of magnesium, the details of ma- nipulation being similar to those observed in estimating magneamm (aide p. 4G5). Half a gramme or rather more of pure dry crystallized phosphate of sodium may be employed in experimental determinations. The official phosphate of ammonium {Amnvmiee Phosphas, B. P.) is quantitatively analyzed by this method. " If twenty grains of this salt be dissolved in water, and solution of aminonio-sulpbate of magnesia added, a crystalline pre- cipitate falls, which, when well washed upon a Alter with siolution of ammonia diluted with an equal volume of watei, dried, and heated to redness, leaves 16.8 grains." Halt a gramme or less is a more convenient quantity, if the operations be conducted with care. Solution of am- monio-sulphate of magnesium (B. P.) is prepared bj' dis- solving 2 parts of sulphate of magnesium, 1 of chloride of ammonium, and 1 of solution of ammonia (20.6 per cent. NH^HO) in 18 or 20 of distilled water ; such a solu- tion is of considerable use if several pliosphoric determi- nations are about to be made.
Process 2 — Free phosphoric acid is most readily deter-
id.y Google
4S2 QUANTITATIVE ANALYSIS.
mined as phosphate of lead (Pb^2P0,). Of the official solution of pliospborto acid it is stated that " 355 grains by weight poui'ed upon 180 grains of oxide of lead in fine powder leave, by evaporation, a residue (principally phos- phate of lead) wliich, after it has been heated to dull red- ness, weighs 215.5 grains." One-tenth of these quantities may be used fov experimental purposes ; one to two grammes will give good results. The oxide of lead must be quite pure ; it should be prepared by digesting red lead in warm dilute nitric acid, washing, drying, and heating the resulting puce-colored plumbic oxide in a covered porcelain crucible. The increase in weight obtained on evaporating a given amount of solution of phosphoric acid with a known weight of perfectly pure oxide of lead CPbO) may be i-egarded as entirely due to phosphoric anhydride (PpJ,
3PbO + Ffi, = Pb,2P0., the actual reaction being,
SPbO + 2H,P0^ = Pb,2P0, -f 3H,0. From these equations, and the table of atomic weiglits {mde Appendix), the percentage of phosphoric acid (HjPOj) in any specimen of its solution may be easily calculated.
Process 3. — The strength of pure solution of phosphoric acid may be ascertained by talting its specific gravity at 15°.5 C. (Vide Appendix.)
Process 4. — Bone-earth, "superphosphate," the Calcis Phosphas of pharmacy, and other forms of phospliate of calcium known to be tolerably free fi'om iron or alumi- nium, may be estimated by treating about half a gramme with hydrochloric acid somewhat diluted, filtering if necessary, warming, precipitating with excess of ammonia, collecting the precipitate (Ca^SPOJ, wasliing, drying, igni- ting, and weigliing. " Calcis phosphas," if pui-e, will, in this process, lose no weight.
Process 5. — Insoluble phosphates in ashes, manures, etc., are treated as follows : a weighed quantity of the material (1.0 to 10.0) is digested in hydrochloric acid diluted with three or four times its built of water ; filtered (the precipi- tate 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
id .y Google
QUESTIONS AND EXERCISES. 483
minnteR, the opalescence is removed; oxalate of ammonium next aMed, tlieivUole warmed, oxalateof calcium removed by filtration, and the filtrate coaceiitvated if ver}' dilute; the liquid treated with citric acid in such quantity that ammonia when added in excess gives a clear lemon-yellow Bolntion (Warington), magnesian mixture poured in (as in Process 1), and the precipitate of aminonio- magnesian phosphate collected, washed, dried, and weighed as already described in connection with the estimation of magnesium.
Melative weights of equivalent quantities of phosphoric compounds.
Phosphoric acid H^PO^ 98
Pyrophosphate of magnesium {MgJ?fi,=2M)-i-2= 111
Phosphate of lead .... (Pb.2PO,=811) -=-3= 405.5 Phosphoric anhydride . . . (P^6,= 142) -r2= U
Phosphate of calcium . . . (Ca,2PO,=310)-^2= 155
Superphosphate of calcium (CaH,2PO^=334) ^ 2= 111
QUESTIONS AND EXERCISES.
s equivalent to 4.2 parts
1011. State the percentage of real iodide of potassium contained in a aampie of wMch 8 parts yield 10.9 of iodide of silver.— -Ihs. 96.25.
1012. What is the strength of a solution of hydrocyanic acid 10 ports of which, by weight, yield .9 of cyanide of silver ?—.d«s. 1.81 per cent.
1013. How are nitrates quantitatively estimated !
1014. By what processes may the strength of sulphides he deter- mined ?
1015. How much real sulphate of sodium is contained in a speci- men 10 parts of which yield 14.2 of sulphate of barium? — Ans. 86.34 per cent.
1016. Give details of the operations performed in the quantitative analysis of carbonates.
1017. What amount of carbonic acid gas should be obtained from 10 parts of acid carbonate {or bicarbonate) of potassium ^—Am. 4c A parts,
1018. To what operation and what quantities of materials docs the following equation refer?
NaAO, + MnO, + 2H,80,= MnSO^ + NXSOi+2H,0 + 2COi,.
id .y Google
184 QUANTITATIVE ANALYSIS.
1020. State the ntnonnt of superphoBphate of caltium eqtiiTalent to 7.6 pacts of pyrophosphate of magnesiuni.— jln*. 8,01 parts.
SILICATES.
Silica (SiOj) may be separated from alkaline silicates, or from silicates decomposable by hydrochloric acid, by digest- ing the substance in hydrochloric acid at a temperature of 70° or 80° C, until completely disintegrated, evaporating to dryness, heating in an air-bath, again moistening with acid, diluting with hot water, filtering, washing, drying, igniting, and weighing.
ESTIMATIOB" OF WATER.
Water,beingreaiiilyvolatiHzed,is most usually estimated by the loss in weight which a substance undergoes on being heated to a proper temperatui-e. Thus, in the British Pharmacopceia, crystalline gallic acid (H,C,H30j, HjO) is stated to lose 9.5 per cent, of its weight at a temperature of 100° C, oxalate of cerium (CeC,0„ SKfi) 53 per cent. on incineration, carbonate of potassium about 16 per cent. on exposure to a red heat, sulphate of quinine (aCjnH^N^Oj, H Sa, TKJ)) UA per cent, at 100° C, arseniate of sodium (Na,H AsO„ IHjO) 40.38 per cent, at 1 49° C, carbonate of sodium (Na,CO^, 10H,O) 63 per cent., phosphate of sodium (NajHP0„12H,0) 63 per cent., and sulphate of sodium (Na,SO„ 10H,O) 55.9 per cent, at a low red heat.
Process. — One or two grammes of substance is saiScient in experiments on desiccation, the niateiial being placed in a watch-glass, covered or uncovered porcelain crucible, or other vessel, according to the temperature to which it is to be exposed. Rapid desiccation 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 tem- perature by aid of a thermometer, and drawing or forcing a current of dry air slowly through the apparatus. Sub- stances liable to oxidation may be desiccated in a current of dried carbonic acid gas. The weights of the TJ-tube before and after the introduction of the salt, and after desiccation, give the amount of water sought. In all cases the material must be heated until it ceases to lose weight. Occasionally it is desirable to estimate water directly by
id .y Google
CARBON, IlYDIiOGE;^, OXYGEN, NITROGEN. 4H5
conveying its vapor in a current of air through a weighed tube containing chloride of calcium and re-weighing the tube at the close of the operation; the increase shows the amount of water.
Note. — Highly dried sahstancea rapidly absorb moisture from the air; they must therefore be weighed quickly, inclosed, if possible, in ' 1. 458), a pair of clamped watch-glasses, or a crucible having
IS (31. A rhtfy t
CAKBON, HYDROGEN, OXYGEN, NimOGEN.
The quantitative analysis of animal and vegetable substances is either proximate or ultimate. Proximate analysis includes the estimation of water, oil, albumen, starch, cellulose, gum, resin, alka- loids, acids, glucosides, ash. It requires the application of much theoretical knowledge and manipulative skill, and cannot well he studied escept under the guidance of a tutor. The beat publislied work on the snbject is by Rochleder, a translation of whose mono- graph will be found in flie Pharmaceutical Journal, vol. i. 2(1 ser. pp. 562, 610 ; vol. ii. 2d ser. pp. 24, 129, 160, 215, 274, 420, 478.
Ultimate organic analysis can only be successfolly accomplished with the appliances of a well-appointed laboratory— a good balance, a gas-fnmaoe giving a smokeless flame {7 or 8 centimetres wide and 70 or 80 centimetres long), special forms of glass apparatus, &c. Tlie theory of the operation is simple : a weighed quantity of a sub- stance is bnmt to carbonic acid gas (OOj=-4:4) and water (HjO^lS), and these products collected and weighed ; 12 parts in every 44 of carbonic acid gas (^y'r) ^""^ carbon, 2 in every 18 of water (=a) are hydrogen ; nitrogen if present escapes aa gas. If nitrogen be a constituent, more of the substance is strongly heated with a mixture of the hydrates of sodium and calcium ; tnese bodies then split np into oxidre, oxygen, and hydro^n; the oxygen bums the carbon of the substance to carbonic acid gas, its hydrogen and nitrogeii appearing as water and ammonia respectively ; the carbonic acid and wutcr are disregarded, the ammonia collected and weighed in the form of a double chloride of platinum and ammonium (PtCl42NH,Cl =447), of which 28 parts in every 447 (=t'a) are nitrogen. The difference between the sum of the weights of hydrogen and carbon, and the weight of substance taken, ia the proportion of oxygen in the body, supposing nitrogen to be absent. If nitrogen is present, the difference between the sum of the percentages of carbon, hydrogen, and nitrogen and 100, is the percentage of oxygen. Shortly, carbon ia estimated in the form of carbonic acid gas, hydrogen as water, nitrogen as ammonia, and oxygen by loss.
The/oUowing is the outlineofthenecessary manipulations.
The source of the oxygen for the combustion of carbon and
hydrogen is black oxide of copper in coarse powder. 200
or 300 grammes of this material are heated in a crucible to
41*
id .y Google
low redness for a sliort tiroe to expel every trace of niois- tiive; then transferred to tubes (store-tubes) resembling test-tubes, half a metre long, and baving a slightly narrowed mouth, the tube being held in a cloth to protect the hand while the hot oxide is being directly introduced into the mouth of the tube by a scooping motion. As soon as the well-corked tube is cool, the oxide is poured, portion by portion, into a similar tube (the combustion-tube), some- what longer, drawn out to a quill (bent upwards nearly to a right-angle) at one end, not constricted at the mouth, and containing a few decigrammes of fused chlorate of potas- sium. After ten or fifteen centimetres of oxide have been poured in, about a decigramme of the substance to be analyzed is dropped down the tube, then a few grammes of oxide, then another decigramme of substance, then moi'e oxide, until three or four decigrammes of the body under examination have been added. The fifteen or twenty centimetres of alternate layers are next thoroughly mixed by a long copper wire having a short helix, more oxide is introduced, the wire cleansed by twisting the helix about in the pure oxide, and a plug of asbestos finally placed on the top of the oxide at about five centimetres from the mouth of the tube ; the tube is then secirrely corked and set aside. The substance operated on may be pure white sugar, powdered and dried ; the tube in whicli it is contained ia weighed before and after the removal of a portion for combustion, the loss is the quantity employed in the experi- ment. If the combust ion-funiace is powerful, or the com- bustion-tube not of the hardest glass, the tube should be inclosed in wire gauze the elasticity of which has been destroyed by heating to redness. In the combustion of substances containing nitrogen, tlie ping of asbestos must be displaced by one of copper turnings, which serve to reduce any oxides of nitrogen, and thus insure the escape of nitrogen itself. The wafer produced when the prepared tube is heated, is collected in a small IT-tube containing pieces of chloride of calcium, or pumice-stone moistened with sulphuric acid ; the carbonic acid gas in a series of bnlhe containing solution of potash (sp. gr. about 1.27). These bulbs may be purchased at any apparatus-shop. The chloride-of-calcium tube is fitted by a good cork to a combustion-tube, the potash-bulbs by a short piece of India- rubber tubing to the chloride-of-calcium tube. The potash- bulbs may carry a short light tube containing a rod of caustic potash three or four centimetres long; this serves
id .y Google
CARLOS, TTYDBOGEN, OXYGEN, NITROGEN. 481
to aiTest any moisture tliat might be cumed away from the solution of potash by the dried expanded air whieh escapes during tlie operation. The combustion-tiibe having been placed in the furnace, aud the drying-tube and potash bulbs weighed and attached, the gas is lit under the asbes- tos, and, when the tube is red-hot, the fiatne slowly extended until nearly the whole tube is at the same temperature, the operation being conducted at snch a rate that bubbles of gas escape through the bulbs at about the rate of one per second. When no more gas passes, the extremity of the tube containing the chlorate of potassium is gently heated until oxj'gen ceases to be evolved; the quilled extremity of the combustion-tube is then broken, and air drawn slowly through the apparatus by auction through an India-rubber tube fixed on the free end of the potash- bulbs, perfect combustion of carbon and removal of all carbonic acid gas is thus insured. The drying-tube and bulbs are disconnected and weighed ; the increase in weight due to carbonic acid gas and water respectively noted, aud the percentages of carbon, hydrogen, and (by loss) oxygen calculated. This method is that of Liebig, with modifica- tions by Bunsen ; one of the best combustion-furnaces is that known as Hofmann's.
The general manipulations for substances containing nitrogen resemble the foregoing so far as the use of a combust ion-tube and furnace and collection of the ammo- niacal gas are concerned. The combustion-tube must be quilled at one end, and about a third of a metre long. The soda-lime is made by slaking quicklime ivith a solu- tion of soda, of such a strength that about two parts of quicklime shall be mixed with one of hydrate of sodium, 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 substance and soda-lime, mixture eifected by a ■wire, more soda-lime added, and lastly a plug of asbestos. Bulbs, known as those of Will and Varrentrapp (the origi- nators of the method), containing hydrochloric acid of about 25 per cent., are then fitted by a cork, and the tube heated in the furnace. When gas ceases to pass, the quill is broken, and aspiration continued slowly until ammo- niacal gas may be considered to have been all removed. The bulbs are disconnected, their contents and rinsings poured into a small dish, solution of perehloride of plati- num added, and the operation completed as in the estiiua-
id.y Google
488 QUANTITATIVE ANALYSTS.
tion of am mo ni urn and potassium salts (vide pages 516 and 459).
Liquids are analyzed by a similar method to that adopted for solids, volatile liquids being inclosed in small bulbs having a long quill. These are weighed previously to and after the introduction of the liquid; just before being dropped into the com bust ion-tube the quill is broken.
Formulse. — From the percentage composition of an organic substance an empirical formula may be deduced by dividing the weight of each constituent by its atomic weiglit, and converting the product into the simplest whole numbers; a rational formula by ascertaining the propor- tion in which the substance unites with a body having a known combining proportion {oide p. 348).
Chlorine, bromine, or iodine contained in an organic substance is usually estimated by heating to redness a given weight of the material with ten times as much pure lime in a combustion-tube. Chloride, bromide, or iodide of calcium is thus produced. While still hot the tube is plunged into water, the mixture of broken glass and powder treated with diluted nitric acid in very slight excesses; the filtered liquid precipitated by nitrate of silver, and the chloride, bromide, or iodide of silver col- lected, washed, dried, and weighed.
Sulphur, phosphorus, and arsenicum. in organic salts may be estimated by gradually heating in a combustion- tube 1 part of the substance with a mixture of 10 parts nitre, 2 dried carbonate of sodium, and 30 chloride of sodium (in order to moderate deflagration). The product is dissolved in water acidulated by nitric acid, the sulphu- ric radical precipitated and estimated as sulphate of barium, the phosphoric and arsenic mdicals as ammonio-maguesian phosphate or arseniate.
aUINIA.
The foUoicing process /or the estimation of the qualUy of yellow cinchona-bark ia from the pages of the British Pharmacopceia: —
Boil 100 grains (or 6 to T grammes) of the bark reduced to very fine powder for a quarter of an hour in a fluid- ounce of distilled water acidulated with ten minims of hydrochloric acid, and allow it to macerate for twenty-four hours. Transfer the whole to a small percolator, and, after the fluid has ceased to drop, add at intervals about
id .y Google
an ounce ancl a half of similarly acidulatecl water, or until the fluid which passes through is free from color. Add to the percolated Buid solntioii of subacetate of lead, until nearly the whole of the coloring-matter has been removed, taking care that the fluid remains acid in reaction. Filter and wash with a little distilled water. To the filtrate add about thirty-five grains of caustic potash, or as much as will cause the precipitate which is at first formed to be nearly redissolved, and afterwards six fluidrachms of pure ether. Then shake briskly, and, having removed the ether, repeat the process twice with three fluidrachms of ether, or until a drop of the ether employed leaves on evaporation scarcely any perceptible residue. Lastly, evaporate the mixed ethereal solutions in a capsule. The residue, which consists of nearly pure quinia, when dry, should weigh not less than 2 grains (2 per cent.), and should be readily soluble in diluted sulphuric acid. (The sulphate — sometimes termed the acid sulphate — of quinia is freelysolublein water, the corresponding salt of quinidia only sparingly soluble. The oxalate of quinia, on the con- trary, is almost insoluble in water, the oxalate of quinidia being readily soluble.) 200 grains of pale cinchona-bark treated in the same manner, with the substitution of chlo- roform for ether, should yield not less than I grain of alka- loids, and 100 of red cinchona-bark 1.5 grain of alkaloids.
A quantitative determination of the purity of commercial sulphate of quinia may be made by De Vry's pi'ocess. 2 grammes of the salt are dissolved in 12 c. c. of distilled water and 1.6 c. c. of diluted sulphuric acid (B. P.). 8 c, c. of solution of hydrate of sodium (I to 12) and 30 c, c. of pure dry ether are added, the whole well shaken and laid aside for twelve hours. The ethereal solution decanted and evaporated gives the quinia. The aqueous solution carefully neutralized by acetic acid and strong solution of iodide of potassium (1 in 4) added, gives a white precipi' tate of hydriodate of quinidia, the mother-liquor contain- ing any cinchonia and cinehonidia that may be present. Tlie precipitate is collected on a tared filter, washed, dried. and weighed; it contains 11.68 per cent, of pure quinidia. The filtrate and washings are rendered alkaline by solution of soda ; cinchonia and cinehonidia are precipitated, and may be collected, washed, dried, and weighed.
Note. — If the quinia in drying assumes a rosinoid character, it should he redissolved in ether, and tlie solution when concentrated allowed to finally evaporate very slowly or spontanconsly.
id .y Google
490 QUANTITATIVE ANALYSIS.
Of the Citrate of Iron and Quinia (Ferri et Quiniee Citras, B. P.) it is offloially stated that " fifty grains dis- solved in a fluidounce of water and treated with a slight excess of ammouia give a white precipitate which, when collected on a filter and dried, weighs eight grains. The precipitate is almost entirely soluble in two or three flni- drachms of pare ether," and the ethereal solution sot aside for twelve hours in a feinaU well-corked bottle yields no crystalline deposit (of quiiiidia).
KOB.FHIA.
The official process fortke estimation of this alkaloid in opium is conducted in the following manner: —
Take of opium 100 grains, slaked lime 100 grains, dis- tilled water 4 ounces. Break down the opium, and steep it in an ounce of the water for twenty-four hours, stirring the mixture frequently. Transfer it to a displacement- apparatus, and pour on the remainder of the water in suc- cessive portions, so as to exhaust the opium by percolation. To the infusion thus obtained, placed in a flask, add the lime, boil for ten minutes, place the undissolved matter on a filter, and wash it with an ounce of boiling water. Acid- ulate the filtered fluid slightly with diluted hydrochloric acid, evaporate it to the bulk of half an ounce, and let it cool. Neutralize cautiously with solution of ammonia, carefully avoiding an excess ; remove by filtration the brown matter which separates, wash it with an ounce of hot water, mix the washings with the filtrate, concentrate the whole to the bulk of half an ounce, and add now solu- tion of ammonia in slight excess. After twenty-four hours collect the precipitated morphia on a weighed filter, wasli it with cold water, and dry it at 212° P. It ought to weigh at least from six to eight grains.
Of Hydrochloraie of Morphia it is stated that " twenty grains of the salt dissolved in half an ounce of warm water, with ammonia added in the slightest possible excess, give on cooling a crystalline precipitate which, when washed with a little cold water and dried by exposure to the air, weighs 15.18 grains,"
Testing Opium. — Professor Schneider has proposed, in the 6tli revised edition of the Pharmacopceia Austriaca, the following method for testing the quality of opium. Ten grammes of previously dried and powdered opium are
id .y Google
SUGAR. 491
treated with a mixture of 150 grammes of distilled water, to which 20 grammes of pure hydrochloric acid, sp. gr, 1.12, are added; the residue, after extraction, should not exceed 4.5 grammes weight; to the acid fluid 20 grammes of com- mon salt are added, and the precipitate thereby caused is collected, after twenty-four hours, on a filter, and the lat- ter washed with a solution of common salt ; to the filtrate ammonia is added, and the fluid left standing again for twenty-four Iiours ; the crystals which have separated are collected, redissolved in acetic acid, and precipitated with ammonia ; the precipitate so obtained is washed, dried, and weighed ; its weight should not be less than 1 gramme.
SUGAE.
The qualitative test for sugar, by means of an alkaline copper solution {mde p, 336), may be applied in the esti- mation of sugar in sacchariferoiis substances.
Process. — 34.Gi grammes of pure dry crystals of ordi- nary sulphate of copper are dissolved in about 250 c. c, of distilled water, 113 grammes of pure crystals of the double tartrate of potassium aud sodium are dissolved in 4^0 c. c, of solution of caustic soda of sp. gr. 1,14. The solutions are mixed and water added to one litre. 100 c. c. of this solution represent 3.464 grammes of sulphate of copper, and correspond to 0.5 of a gramme of pure anhydrous grape-sugar, 0.415 of cane-sugar, or 0.45 of starch. It must be preserved in a well- stoppered bottle to prevent absorp- tion of carbonic acid, and be kept in a dark place. If it give a precipitate on boiling, a little solution of soda may be added in making experiments.
Dissolve 0.475 of pure dry powdered cane-sugar in about 50 c, c. of water, convert into grape-sugar by acidulating with sulphuric acid, and boiling for an hour or two, neu- tralize with carbonate of sodium, and dilute to 100 c, c. Place 10 c. c. of the copper solution in a small flask, dilute with three or four times its bulk of water, and gently boil. Into the boiling liquid drop the solution of sugar from a burette, one cubic centimetre, or less, at a time, until, after standing for the precipitate to subside, the snpei^natant liquid has just lost its blue color; 10 c. c. of the solution of the sugar should be required to produce this efl'ect, = 0.415 of cane-sugar or 0.5 of grape-sugar. Experiments on pure cane-sugar must be practised until accuracy is
id .y Google
403
QUANTITA
attained; syrups, diahetio urine, and saccliarated sub- stances containiug unknown quantities of sugar may tlien be analyzed.
Starch is converted into grape-sugai- by gentle ebii 11 it ion with dilute acid for eight or ten hours, tlie solution being finally diluted so that one part of starch, or rather sugar, shall be contained in about 150 of water.
Saccharimetry. — A generic term for certain volumetric operations undertaken with the view of ascertaining the quantity of sugar present in any matter in which it may be contained.
Saccharimetry is frequently perfonned upon common syrup (Syrupus, B. P.) and solutions which are known to contain nothing but cane- (ordinary) sugar, the object being merely to ascertain the amount present. In such a case it is only necessary to take the specific gravity of the liquid at 60° F., and then refer to a previously prepared Table of densities and percentages.
|
1.001 . |
1.8 |
1.100 |
. 23,1 |
1.910 . . |
46.3 |
|
1.014 . |
3.5 |
1.108 |
. 25.6 |
1.231 . . |
48.1 |
|
1.022 . |
5.2 |
1.U6 |
. -31.6 |
1.231 . , |
50.0 |
|
1.029 . |
7.0 |
1.125 |
. 29.4 |
1,242 . . |
52.1 |
|
l.OSfi . |
8.7 |
1,134 |
. 81.5 |
1.252 . . |
54.1 |
|
1.044 . |
10.4 |
1.043 |
. 33.4 |
1.261 . . |
56.0 |
|
1.052 . |
12.4 |
1,152 |
. 35.2 |
1.215 . . |
58.0 |
|
1.060 . |
14.4 |
1.161 |
. 31.0 |
1.286 . . |
60.1 |
|
i.oer . |
16.3 |
l.Ul |
. 88.8 |
1.298 . . |
62.2 |
|
1.015 . |
18.3 |
1.180 |
. 40.6 |
1.309 . . |
64.4 |
|
1.083 . |
20.0 |
1.190 |
. 42.4 |
1.321 . . |
66.6? |
|
1.091 . |
21.8 |
1.199 |
. 44.3 |
1.330 (B.P. |
66.6? |
The sp, gr. may be taken by an hydrometer, technically termed a saccharmneter. (The above spec, gravs.^l^ to 35° Baum^.)
If a liquid contains other substances besides cane-sugar, the test of specific gravity is of little or no value. Advan- tage may then be taken of the fact that syrup causes right- handed twisting of a ray of plane polarized light to an extent exactly proportionate to the amount of sugar in solu- tion. The saccharine fluid is placed in a long tube having opaque sides and transparent ends; and a ray of homoge- neous light, polarized by reflection from a black-glass mir- ror or otherwise, is sent through the liquid and optically
id .y Google
ALOOilOL. 493
examined by a plate of tourmaline, Nicol'a prism, or other polarizing eyepiece. Attached to the eyepiece is a short arm which traverses a circle divided into degrees. Tlie eyepiece and arm are previously so adjusted that when the ray is no longer visible the arm points to the zero of the scale of degrees. The saccharine solution, however, so twists the ray as to again render it visible ; and the num- ber of degrees which tiie eyepiece has to be rotated before the ray is once more invisible ia exactly proportionate to the strength of tbe solution. The value of the degrees having been ascertained by direct experiment and the results tabulated, a reference to the Table at once indicates the percentage of sugar in the liquid under examination. Grape-sugar also possesses the property of dextro-rotation, but less powerfully than cane-sugar ; moreover the former variety does not, like cane-sugar, sutfer inversion of the direction of rotation on the addition of hydrochloric acid to its solution — an operation that furnishes data for ascer- taining the amounts of cane- and of grape-sugar, or of crys- tallizable and noii-crystallizable sugar, present in a mixture. In using the polariscope-saccharoineter, it is convenient to employ tubes of uniform size, and always to operate at the same temperature.
ALCOHOL.
Mulder's process for the determination of the amount of alcohol in wines, beer, tinctures, and other alcoholic liquids containing vegetable matter is as follows: Take the spe- cific gravity and temperature of the liquid, and measure off a certain quantity {100 cubic centimetres); evaporate to one-haif or less, avoiding ebullition in order that parti- cles of the material may not be carried away by the ateam. Dilute with water to the original bulk, and take the specific gravity at the same temperature as before. Of the figures representing this latter specific gravity, all over 1,000 show to what extent dissolved solid matter afi'ected the original specific gravity of the liquid. Thus, the specific gravity of a sample of wine at 15o.5 C. is 0.9951 ; evaporated till all alcohol is removed and diluted with water to the original bulk, the specific gravity at 15°.5 C. is 1.0081 : 0.0081 re- presents the gravitating effect of dissolved solid matter in 0.9951 parts of original wine. 0.0081 subtracted from 0.9951 leaves 0.981, which is the specific gravity of the water and alcohol of the wine. On referring to a Table of 42
id .y Google
494 DIALYSIS.
the atrengtlis of diluted alcohol of different specific gravi- ties (p. 506), 0.981 at li°.5 C. is found to indicate a spirit containing 8 per cent, of real alcohol. ■ If the foregoing operation be conducted in a retort, the liquid being boiled and the steam carefully condensed, the distillate, diluted ■with water to the original balk of wine operated on, will still more accurately represent the amount of water and alcohol in the wine — its specific gravity showing the per- centage of real alcohol present.
DIALYSIS.
Dialysis (from Xia, dia, through, and ^inij, lusis, a loosing or resolving) is a term applied by Graham to a process of analysis by diffusion through a septum. The apparatus used in the process is called a dialyier, and is constructed and employed in the following manner. The most conve- nient septum is the commercial article known as parchment paper, made by immersing unsized paper for a short time in sulphuric acid; it is sold by most dealers in chemical apparatus. 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. Liquids to be dialyzed arc poured into the dialyzer, which is then floated in a flat dish containing distilled water.
The practical value of dialysis depends upon the fact that certain substances will diffuse through a given septum far more rapidly than others. TTncrystallizable bodies diffuse very slowly. Of such matters aa starch, gum, albumen, and gelatine, the last named is perhaps least diffusive; hence substances of this class are termed co/toids, or bodies like collin, which is the soluble form of gelatine. Substances which diffuse rapidly are mostly crystalline; hence bodies of this class are termed cri/stalloids.
Solutions of two partsof the following named substances in 100 parts of distilled water were dialyzed by Graham for twenty-four hours. The amounts of each substance which passed through the septum bore the following rela- tions to one another ; —
id .y Google
DIALYSIS. 495
Chloride of sodium 1000
Ammonia 847
Theine 703
Saliciii 503
Cane-sugar 472
Amygdaliii Extract of h
Catechu 159
Extract of cochineal 51
Gallo-tannic acid 30
Extract of litmus 19
pHrifled caramel 5
Ten-per-cent. solutions, under similar circumstances, gave the following results; —
Gum Arabic ....... i
Starch-sugar 2G6
Cane-sugar 214
Glycerine 440
Alcohol 476
Chloride of sodium 1000
The phenomena of dialysis show that crystalloids are superior to colloids in affinity for water. If a solution of chloride of sodium be placed at the bottom of a jar, and covered by a hot solution of gelatine of sufficient strength to solidify on cooling, the chloride of sodium will diffuse up into the solid jelly, because the water of the solid jelly has a greater affinity for the salt than it has for the gelatine. The solid jelly may obviously be reduced in thicltness, and saline liquids placed above it ; indeed the conditions would then be still more favorable for diffusion. Replace the stratum of jelly by a permanent colloid, such as parch- ment paper ; the result is the same, but the permanent character of the septum admits of its practical application. Further researches on dialysis wlU probably throw much light on several important points in connection with phy- siological chemistry; for thereislittledoubt that alimentary matter passes through the cell-walls of animals and plants by this process.
QUESTIONS AND EXERCISES.
1021. Carbonate of potassium is said to lose 16 per cent, of water on exposure to a red heat ; give the details of manipnlation obsetTed in verifying this statement.
id .y Google
1022. Write a few pant,n.pha deacuitiic of fhc jiioccss (f ulti
in quantitative analysis !
1024. In the combustion of 41 of a giamine of sugar nliat weights of products will be obtained? — Aiis C32 of cnrbonit acid gas (COJ and .237 of water {H,0)
1025. Describe De Vry s process for the assay of commei-cnl quinia.
1026. Give the ofEcial method for the estimation of morphia iu opiam.
102". Mention the operations necessary for the estimation of the proportion of sugar in aaccharated carbonate of iron, or in a speci- men of diabetic nrine.
1028. What is understood by sacckarimefrj/ ?
1029. Give two processes for the estimation of tlie percentage of alcohol in tinetuM^, wines, or beer.
1030. Define dialysis.
CONcr.usiON,
Detailed inetnictions for the quantitative analysis of potable 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, ivould scarcely be in place in this Tolume.
The course through which the reader has been conducted will, it ia hoped, have taught the principles of the science of chemistry, and given special knowledge concerning the applications of that science to medicine and pharmacy, as well as have imparted sufficient manipulative skill to meet the requirements of manufactui-e or analysis. The author would ventureto suggest that this knowledge be utilized, not only in the way of personal advantage, but in experimental researches on chemical subjects connected with therajieu- tics and phannacy. The discovery and publication of a. new truth, great or small, is the best means whereby to aid in advancing the calling in wbich we may be engaged, benefit our fellow creatures, and glorify tlie Creator of all things.
id .y Google
APPENDIX.
|
K |
me of Pteparatlon |
ImputUie.. |
Te>i. |
P"8«. |
|
* |
""■^ |
mora Ibo.n one-tlionsRndtl. |
479 |
|
|
Hitrale of Silver. . . |
||||
|
A. |
dumCUrlcn,. ■■ |
Chloride or Mllraie of Ba- |
||
|
Chloride or Nitrate of B^ |
||||
|
Sulpliuric acid . . . . |
||||
|
^% |
ium Hj'iroclilo- |
A„.«i= |
£58 |
|
|
/a^^e^L^kydr^gen ! ! ] |
asa |
|||
|
Ac |
Uin Hjd.^cri- 1 |
Sulpburic icid .... |
||
|
Hyilfccliloric add . , . |
Ppt-byHllr.ailyer.lniiDl. |
3M |
||
|
Ac |
Sulphuric acid .... |
Z5B |
||
|
aaa |
||||
|
9alphuri=acid . . . . |
||||
|
A,^ |
dui Phoiplioci- |
Hydtocblorio acid . . . |
||
|
'S"".".:!?""-": |
£22 237 |
|||
The olbar "cberaolera and t*8ls" nf pbarmaconffllal compoands bave liaen slvaa in cobneotlon irllh the respecttve iiTDtbetlcal aud aaal^lleal reaeUons.
id .y Google
|
Test. |
roge. |
||
|
Add««i Sulphari- \ |
Ni«"o''i>"""'' ■ ■ ■ * |
EYBputstlon and JgnUlon , |
S27 |
|
AcidumSulpliurosuB. |
2M |
||
|
AciamTmncumJ |
|||
|
Mineral metter .... |
2M |
||
|
Anbjdroas Sulphate of |
34B |
||
|
Amylnin . . . . j |
Acw'matl?*"^' ■ ■ ■ ■ |
||
|
InsoimiilllylnHCl. . . |
|||
|
AnLimonuOKidiim. . |
140 |
||
|
Aatimonium TarlMR |
Gonctal ■ |
468 |
|
|
Jlelsllic matfer (Pb, Cu, |
Snlpliatelted H^dioeen . |
||
|
Sulphate. |
Chloride otMilrataot Ba- |
||
|
1,S |
|||
|
AtrMw SaiphM' '. |
Ml™lm'lter ■ ■ ■ |
7* |
|
|
3M |
|||
|
Kftrales (or BLamuth or |
|||
|
Leid (OBiboiiate) . . CUloride (as;cbloride sf |
|||
|
ElBrautLi Sobnilraa |
|||
|
AmiDOoia le SitrioBolut'n |
|||
|
B.™„. .... 5 |
'5™''™' |
Bpedflc eraviljr (463) and |
|
|
'"■''"" |
Hoa,d, Google
|
K„„.IP,.,„.ll™. |
la.parl.1cs. |
Tcsl. |
rase. |
|
|
c...»™. |
P(«- |
ZlLc(io.Udel |
s|n^hydra"of'Ai^m>" QiiMitllaitTe aoalTiii '. '. Hydrochloric acid , . . BSeneBcence vllh acids . Solulion of potash . . . iBsolubUitylnBcld. . , Saco, sol. of Ume, to sol. M*Se mr^n"".''? : : flon-Tolalllity . , . . IfldnerBtloi. ibj- help of Melliug-polnt Meitlus-polat Solnbllitv io Alcohol . . iDsolulititly itt Tarpen- Aah bol. ia"aclds wlibrf- InflolubllltyofHydrBlflio ""at^otarh'!"^ ^. V'. Melting-point lacoDiplele soloblllly in Oxidation \ '. '. \^'. '. Deilro-cotatlon of polar- Ciystallljaliouon cooling QuantllatlTO anaiysis ' aaaSilBU™ Bnaiysis ! Ebnllllion with potash and anaDtltatlTe an^y'si^ . AlkalioilyofBBh . . |
20. |
|
CaldiChlorid cipitBll . |
?S3S5".'"!'-: Aluuiini, Oslde of Iron, and Pbosphales. |
^ |
||
|
C8rboBBle3{orCaliiiBDi) . |
m |
|||
|
Is |
Alnmlns, Oslda of Iron, |
^a |
||
|
.i..». |
^f- |
|||
|
Cambogia . Cb"o AntmBl &x\ll |
||||
|
Earthy salts '.'.'.'.'. MorethBtt2petct.otBsli |
||||
|
•1 |
||||
|
"SK"-""'™ |
2W |
|||
|
G 1 |
188 |
|||
|
135 |
||||
|
■■1 |
||||
|
Chloroform |
HydrocAi-boQs , . . |
SHI |
||
|
Ciiprl Sulpha |
1 ■-i |
C.,l,»l..acid |
h^^T-'^l ' |
!! |
|
Fol BovlQiiio |
Macns, ciade Sulphate of ( |
odiam) . |
aw |
|
|
"^^IS?^" |
^9 |
|||
|
CilrBS . |
Tartrate (of iron and am moLluin) |
|||
|
F«nl ot Qniu |
odlam.inlts odluia, Silts |
|||
|
Alkaloids ot Ola, |
er thaa Qal |
|||
|
Mag- |
||||
Hoa,d, Google
|
500 |
APPENDIX. |
||
|
N.o.eofProp^r.lio. |
In.p,iHti.H. |
Te«, |
Page. |
|
Fe,TC.n8 bydrala . . . |
Red prnasLate lo a^id .0- |
||
|
P«rlD oijliydraW . . |
Inselubillly is cold an |
138 |
|
|
Pg..of^8,«»quao«a,ol |
12* |
||
|
Fscious compoDDds . |
|||
|
Ferram Tarlarfttam- |
Soda"" :::::; QnanlilallTa analj.U . |
487 |
|
|
Hj:^li;f, io.,au. |
FisedsalW |
m |
|
|
Corf ml ve Subliniata |
Tr«a'na°8Lt iilii e'ther * |
m |
|
|
Fixed «»Us |
koL-.oUtllilr . . . |
||
|
Hylrargyium |
Fixed in=lBl» (Pb, Bn. Zn Kxk^iu |
103 |
|
|
Hydraigj'tun. Ammo- |
BoE,.volali!it7 . . . . |
m |
|
|
Jlercurio osida |
SUnno as chloride to sol in |
||
|
CjaoLde of loaina . . DeBeiepcyotCilrioaijia |
Pbysicil chatactara . . QnantlUttvaanslrri.^.^. daantltatlTe anafyslB . '. |
||
|
J^lapB Eeslni . . |
m |
||
|
"•-■■■ ! General impntitj- or da£ |
|||
|
Liquor Ammoniio |
^Si'-" !'/-"■ |
||
|
SulpLur salts (AjnHS). |
|||
|
SulpHateofAmmoaiom . |
|||
|
LLq.AntimodiiChlo- |
'i'^*^^"' ; |
u* |
|
|
*ss |
|||
|
Liq.AraeniciHydrg-j- |
aaantltalive analyds . 1 |
«fl |
|
|
Liq.BimuthietAm- |
470 |
||
|
Lll.Cakls |
Seeciecsjr in BtFength , . |
QuanlitatlTO anaiyiU . . |
|
|
Llq. CiMi Si/cha-i |
"I'lrJr'T"''! "'.''!'{ |
Specific gravity .... QaaQtilallreaiB!ysla(o07] |
m |
|
Oeneml qnalUj .... |
|||
|
' |
Peflclencjioalrenglh. . |
QLii.nlila.tlYe analyaiB , . |
i^ |
Hoa,d, Google
APPENDIX.
|
Kama ot Prepir t oa luiiiDritles. |
Te«. |
P.go. |
||
|
BedPrnaslate . . . . |
||||
|
GeneraLimpurllrordc-j flclcncy j MercuronasalU (nitrate) . Qaneral Impnritj- or dafl- Qenctal impnrily or defl- neoManmpnrityorde. |
||||
|
I,,g/d.a.«,riJj Liq Lithis Efferves I.^ "llagiiM » Cat i bODBtis j Lq PlMDb SdbacB j |
QuabUlallve analysis . . l^d1S^bT;:t]^?eid : : : ftuanHlatlte analysis, ic. Bitter taste (MgC1,MgS0.|. Quantitaliyeaoilysis. . Speciflc gravily . . . . luantllatWe aaalysis . . Qranfitadvl aiaiysi. " " |
437 |
||
|
«■;>••«»— 1 |
etrei'vescence with aoidi . |
2as |
||
|
Liquor Polaisio . .- |
traces of Chlorides . |
wi |
||
|
Nitrate of Ml.et to aeld |
„„ |
|||
|
'——'■"■ |
Doflcieacylnalrengeh General ioipurilj or d |
■1 |
Tarlm'i'c ac'idr&o!^" ; '. BpcclSo graTtly . . . . QuautltBliie aiis,1rEie . . Etfetvesceaee with acids . lusoLlnaeide after eYap&o BaCIj to acid sol. . . . AgBd,^to^aridso^l.^^. . . tTacid sol. ". . " "(fl^ aoaatitative analysis . . Buantilaiive aoilysis . '. QufljilltalLe analysis . Lime-water, 4c. . . . |
1 |
|
Liquor aod=5. . .- |
Carbonate lofsodlom) More tbin J StUphttte ^traces of I^^WWe, |
1 efi- |
^1 |
|
|
LUhiffl Carbouas .4 |
Deacleoej' in strength ,. |
*M |
||
|
Msgnesia .... Map.eala LeTla . . |
DcflcioncT in strepgih . Calcium (by d rate ot tar bonita). Sulphates {o[ magDesinm |
I |
||
|
Clilorlde of Barium to acid Oxalic'aclii' to' Ainiaoala- cal solution .... Suantjiative Bpaljeis . QuantifatiTe aualysia . QimntitatiTa analysis . CuiiatilsitTa a'caiysis '. |
||||
|
DlngQ^sis; Carbodas |
Cafci™°"a;boiiale) . |
" |
||
|
MagocBlffl Sulphas . |
General Inipovity or d cl'ldum (SDlphate) . General impnrilies . |
ofi |
J |
|
|
Gsnecal Imputlties . |
m |
Hoa,d, Google
|
NimeofPreparatio,!. |
IiapurttieB. |
Teat. |
Pago. |
|
J |
Fixed oil |
reimauent j esaf a a d |
|
|
Al^hal |
^rl^KTeV"""' |
||
|
Oplnm |
Doaolencr In motpbls . |
||
|
PlumMAcetas . . . |
|||
|
( |
Solphalo' ot Lfsafl or Bh- |
||
|
[ 172. 7B) |
|||
|
Plumh CMbonas . ^ |
Calciuiu (chalk) . . . . |
OxaLAnmoonmaferro- moilnf, L(ad |
iljfl |
|
M«rthar't^i'i="^«- '■ |
|||
|
Nitrate of all.er to acid |
222 |
||
|
PotiBM Caustics . - |
traces of jsuipbale . |
ChloriieofBarBm oacfl |
til |
|
Oeoeral Itupuiillea (water |
QLantitativB analyala |
||
|
ExcWs or Caiboaate 0! |
|||
|
Snlpbste. |
601. in ipl 11 |
||
|
Iron and olhec melalliij |
Snlphjdrate of Ammo- |
||
|
m |
|||
|
' |
^sttrr-oiuMuV |
ai9 |
|
|
Potasas Bicarionas . |
General . .^^.^ . . |
aoantl illFe analysia |
m |
|
P^lasM Csrbonaa . - |
"^"'oMS"'P'""« ■ |
Chlirl'deofBwmmtoacld |
|
|
General '. '. |
|||
|
ChlorldeCofpolaasium) . |
nitrate otSlver |
||
|
GHlclum (cliloride) . . . |
|||
|
QuButUatlTe aaalf^a |
|||
|
Polaasffi Nlttas ! ( |
ChlorldBof Balnm |
||
|
Chloride (of potaaslnmi . |
KltratB of Silver |
"82 |
|
|
Polasss Sulphas . |
Calelnm (sulphaie) . . . |
O^aiEfAmnonlam |
sa |
|
Polassffi Tatltas . |
General |
dnantilBlive analjaia |
«i |
|
Free bromine. .. . . . |
|||
|
PolBss^i Bcoutidnm |
Chloclne-irater aait starch |
||
|
Oeoerai |
|||
|
Pola=sli reri-idcjanl. |
Farrocjanids (of potas- |
||
|
Potassinodldum . ' |
CbloridB (of potaBslum) . |
HilrataotSUYOr 4o |
|
|
aacc. solution of Lime |
|||
|
Qninlie Snipbas . . |
Salloin |
Sulphur 0 amd Bo?rck'a' d ''°^'*'' |
m |
|
Kliei Radix . . . . |
|||
|
BiHhy aoflpa, &c. '. '. . |
Inaolub J nepirt |
||
|
Sapo DUL'US . . . |
|||
|
SspoJlQlliS . . . |
Eailby Boapa, iic. . . |
Inaolubtllty In spirit |
|
|
Inner anrftte of Potato |
|||
|
paili g |
|||
|
I |
Eesia of Jalap . . . |
||
|
i |
Carbonate (uf calelnm and |
||
|
Sca^moi.i«m . . 1 Eioapl5 |
Si"fhm""r)'- ■ - - Si^rcli iluur) .... |
^oisiirHorst |
" |
id, Google
APPENDIX.
|
Hame otPreparallon. |
loipurltles. |
Teal. |
r.ge. |
|
Soiln Cauatica . . J |
More than ( Chloride . . traces of i Sulphate . , SeS'"'^'^"''*'""^ Suiphatea (sod^nmor^ai- Cblorid'ea (andiam or cal- ler of cryBtailizalloa. tracea at \ Snlpl.ales . . traces of"! s'ulpbatea! '. ■3eneral Chloride (oraodlnm) . . Bulphate(ofaodliiin) . , More Ihau Irace ot Sul- Dofidoo. or sscsaa ot Excess or deOolency of Goneral'cexoess of water). Earthy matter . . , Trace of Acid (H.SO. or s?,Ss'..,,.J.,™ Tracea of Copper . . . |
?h'lo.-id?o"Xr!«mtoadd |
'"' |
|
Quautitalive analysis . . QixanlUaUve analysis . . ClilorldeofBarlniatoacia |
11 |
||
|
ao" *!.'"'?.. |
I |
||
|
.,.c.,w.„. .| |
Quantifative analysis . , QuanlitatiYe analysis . . Chiorideo/Barhimto^id |
= |
|
|
Sodffl HypoanlphiB . SoJic Phosplias . . ) SoiiJB Sulphas . . -| Spill tusCiiiorofornii Bpiritua Tenulor . . |
Chlortiie'or'Kltra'to of Ba^ Q"a°n'lit^t?ve analysis: '. Solut'n of potash healed! QaaBlltaliveBnalyBia . . Quaatitali™ analysis . . Insolnbiiityla'aplrli '. '. SprtI tic gravity , . . . EITervoaeoncfl with bicar- bonate of sodium ; . . Spoclflc gravity .... |
473 |
|
|
Snlphur Prujcipita- ) |
Appearance aoder laiiro |
74 |
|
|
Snip hurts lodlduiB Syi-upl |
Residue on igeitioB . . Quautltatl»e analysis '. Sped a c gravity , , . |
^6 |
|
|
V.r^trta .... |
I"""""" ■ ■ ■ |
7.1 |
Hoa,d, Google
APPENDIX.
|
Haoie of PrepEvralloL, ' Itnpurilies. |
T«8t, |
Fase. |
||
|
MelaLs(A^Cd, C'u,pb Sfffir.'-'r': : SnlpHales .... Cslciani (ohloTlde) . ForrouB saimchlorlde FBirie tail" (chloride) SulplistMlsmllDmod Cop'peVloxfde) '. '. MelaU (As.Cd 'cu,Pb) Iron (iulpliBle) . . Copper (aulphslel . |
.., |
CLlorLde or Nilri.lo of Bb- |
||
|
Kitrale of Silver. . . , SulphnrMled Hydrogen . HUrlcAoid: Ammcsia . Chloride or Nitraw of Bi- CblorldeorMllfalaTBa- Fertldcyanideof PotasB'm rerrocyanido of Polsss'iu Salpbgrelted hjdrogen . |
152 |
|||
|
Butyrale (of zIm) . |
Aoelale of Copper, 4c. , |
322 |
Hoa,d, Google
|
H |
SSS^ |
SSSS |
|
It |
psi |
S3oS |
|
111 ill |
ill |
3||g |
|
§11 |
|pi |
|
|
.i-,S |
iisl |
gsss Slid' |
|
IJI |
ss§s |
iiis |
|
.. .9 |
18.GG 20.00 21.90 26.66 38.13 22.40 16.73 12.73 |
.S" S3
■Ills
j4ol|-'-
i|2
+H||i
s ssSri
s^ g g g
is
IS
;k il«
3|iSnI|ie.|gai
reo .2
'^ §.§ all a|"-K.g
ilES|&||.|g-^.
T.|l|.|.||||*| 1111111111-
jllll|s Si's
i Sll.il.illSS^
Hoa,d, Google
APrBNDIX.
THE PROPORTION BY WEIQIIT OF ABSOLUTB OU PLAIN ALCOHOL
(CjHjHO) IN 100 PARTS or real spirits of diefeeent
SPECIFIC GRAVITIES (pOWNES).
0.9991 , . 0.9981 . . 0.9965 .. 0.9941 ., 0.9930 . . 0.9914 . . 0.9898 . .
0.9869 . . 0.9855 . . 0.9841 . , 0.9828 . . 0.9815 . . 0.9803 . . 0.9T89 .. 0.97T8 .. 0.9'!6fi . . 0.9153 . . 0.9141 .. 0.9128 . . 0.9716 .. 0.9104 .. 0.9691 , . 0.9618 . . 0.9665 . . 0.9652 . . 0.9638 . . 0.9623 . . 0.9609 , . 0.9593 . . 0.9518 . . 0.9560 . . 0.9.^44 . . 0.9528 . .
|
P grit 60= |
C9^"g0 |
Sp.gr. It eoo |
|
|
li<6 C,|. |
of reAl |
(is^oc). |
|
|
0.9511 . |
.. 34 |
0.8769 ... |
|
|
0.9490 . |
.. 35 |
0.8745 |
|
|
0.9410 . |
.. 36 |
0.8721 |
|
|
0.9452 . |
.. 37 |
0.8696 |
|
|
0.9434 . |
.. 38 |
0.8672 |
|
|
0.9416 . |
.. 39 |
0.8649 |
|
|
0.9396 . |
.. 40 |
0.8625 |
|
|
0.9316 . |
.. 41 |
0.8603 |
|
|
0.9356 . |
.. 42 |
0.8581 |
|
|
0.9335 . |
.. 43 |
0.8557 |
|
|
0.9314 . |
.. 44 |
0.8533 |
|
|
0.9292 . |
.. 45 |
0.8508 |
|
|
0.9210 . |
.. 46 |
0.8483 |
|
|
0.9249 . |
.. 41 |
0.8459 |
|
|
0.9228 . |
.. 48 |
0.8434 |
|
|
0.9206 . |
.. 49 |
0.8408 |
|
|
0.9184 . |
.. 50 |
0.8382 |
|
|
0.9160 . |
.. 51 |
0.8357 |
|
|
0.9135 . |
.. 52 |
0.8331 |
|
|
0.9113 . |
.. 53 |
0.8305 |
|
|
0.9090 . |
.. 54 |
0.8279 |
|
|
0.9069 . |
.. 55 |
0.8254 |
|
|
0.9047 . |
.. 56 |
0.8228 |
|
|
0.9025 . |
.. 61 |
0.8199 |
|
|
0,9001 . |
.. 58 |
0.8112 |
|
|
0.8979 . |
.. 59 |
0.8145 |
|
|
0.8956 . |
.. 60 |
0.8118 |
|
|
0.8932 . |
.. 61 |
0.8089 |
|
|
0.8908 . |
.. 62 |
0.8061 |
|
|
0.8886 . |
.. 63 |
0.8031 |
|
|
0.8803 . |
., 64 |
0.8001 |
|
|
0.8840 . |
.. 65 |
0.1969 |
|
|
0.8816 . |
.. 66 |
0.1938 |
|
|
0.8193 . |
.. 61 |
id .y Google
APPENDIX,
THE ELEMENTS.
Aluminium (AIT') Al'"' 21.5
Antimony (Sb"^) Sb'^ 122
Arsenicum (As"') As^" 75
Barium ....... Ba" 131
Beryllium (Glucinum) .... lie" 9.5
Bismuth (Bi™) Bi'' 210
Boron B'" U
Bromine («.7i, sias) Br' 80
Cadmium Od" 112
CBBsium Cm' 133
Calcium (Ui" 40
Carbon (C") C"'" 12
Cerium (Ce") Co" 92
Chlorioe (m.sss, sm.) CI' 35.5
Chromium (Cr/') Ci~"' 52.5
Cobalt (Co") Co^"' 58.8
Copper Cu" 63.5
Didymium T)" ' 9li
Erbium? Eb" 112.6
Fluorine F' 19
Glucinum, Stie Beryllium.
Gold All"' 106.1
Hydrogen H' 1
Indium lu^'' 15.6
Iodine (125,633, etaa) 1' 121
Iridium Ir" 191
Iron (Fe" & Fe/') Fc'''' 56
Lanthanium ...... L" 93
Lead ("Pb") . . , . ' , . Pb''' 201
Lithium (i.m, m^) Li" 1
Magnesium Mg" 24
Manganese (Mn" & Mn") , . . Mu^' 65
Mercury Ilg" 200
Molybdenum Mo''' 96
Nickel (Ni") . . ... Ni" 58,8
Niobium Nb^ 97.6
Nitrogen (N' & N"') (u.om. sia.) . . N'^ 14
Osmium Os"' 199
Oxygen (3s 5c, SHs) O" 16
Palladium ...... Pd'^ 106.5
Phosphorus (P'") P'^ 31
id .y Google
APPENDIX.
Platiiuim (1S7.SS, Androwa) .... Pt" 198 Potassium (39.04, stae) . . . . K' 39
Khodium Kli"' 104
Rubidium ItV 85.5
Ruthenium Ru'^ 10*
Selenium Se^'' 79
Silicon Si" 28
Silver (107.B8, siaa) Ag' 108
Sodium (22.1)8, si»«) Ka' 23
Strontium Sr" 81.5
Sulphur (S" & S") .... S''"^ 32
Tantalum Ta" 131.5
Tellurium To" 139
Thallium (m. Crookea) .... Tl'" 304
Thorinum or Thorium . . . . Tli" 115.7
Tin(8n") Sti''' IIS
Titanium Ti'''' 50
Tungsten W' 184
Uranium V' 120
Vanadium ...... Y^' 51.3
Yttrium Y" G8
Zinc Zu" G5
Zirconium Zi'^' 90
Total ... 63
The giianthalence or atomio value of some elements is, apparenHy, variable; in the above Table the fuli coeffici«iit3 are given in the column of symbols, other common values in brackets.
Atoinic ivci'jhis are someiimes obscurety termed equb-aJ<:ril!!.
id .y Google
INDEX.
Abm laUamea, 380
canadimi^, 381 Abaintbin, 331 Absinthium, 331 Absolute alcohol. SJ8, 411 Acacite gvmmi, 84
gummi, impurities in, 497 Acetate of ammonium, solutioD of,
|
potassium, 46 |
clilorc 24C 243 |
|
SDctium, 58 |
chola] c 3 1 |
|
ainc. 99 |
chrome lis |
|
Acetates, 245 |
chrys-ila c 277 |
|
analylioal reactions of, 247 |
C unam c 382 |
|
AoeUoacid, 47. 216, 373 |
olonholc 379 |
|
glieial, 24(i, 415 |
colophon c 879 |
|
oopavo 880 |
|
|
445 |
cjan c 2 8 |
|
Acetone, 248 |
i 1 0 81 |
|
Acetonitrate of barium, 95 |
|
|
Acelum, 245 |
cugen c 1 6 ^ |
|
cantharidU, 245 |
|
|
colchici. 245 |
gall J 95 |
|
gamboge 881 |
|
|
gaultberc 362 |
|
|
lobdite, 246 |
glac al acet a 24G, 416 |
|
opii, 245 |
gummo 833 |
|
hemidesmic, 277 |
|
|
soillffi, 245 |
hippuric, 279, 398, 401 |
|
Acetyl, 246 |
hydriodic, 225 |
|
Aoid, acetic, 245, 246, 373 |
hydrobromic, 223 |
|
acetic, glacial, 24B,41S |
Lydrocblorlc, 25, 219, 220 |
|
arabic, 333 |
dilute. 220 |
|
angelic, 8T5 |
hydrooyauio, 230, 341, 368 |
|
arachidio, 878 |
hydroferridoyanio. 2SI |
|
arsenic, 130 |
hydroferroojanlc, 279 |
butyric, 299, 373 caproic, 373
cathartc 841
id .y Google
|
510 INDEX. |
|
|
Ada— |
Acid— |
|
hydrofluorie, 281 |
sulpliurooa, 26, 252 |
|
bydroaulphuric, 249 |
Bulpbydrio, 240 |
|
hypoohlorous, 240 |
eylvio, 379 |
|
liypophosphorous, 282 |
tannic, 293 |
|
tartnric. 2ti3, 292 |
|
|
lodio J44 |
tetratbioiiic, 284 |
|
Iiotio 285 |
trithionic, 284 |
|
kunc 3 S |
urio, 296 |
|
mahc 280 |
ynlerianic. 297, 378 |
|
Acid carbonate of potiisaiuni, 47 |
|
|
meeomo ^87, 892 |
onrbonate of sodium, 58 |
|
nie1,s6.c S-3 |
M!ts, 50, 249 |
|
metabaracic, 274 |
tartrate of potassium, 42, 64 |
|
metagummio, 333 |
tartrate of aodium, 65 |
|
Acidimetry, 445 |
|
|
raetsphos^horio, 287 |
Acids, analytical detection of, 313 |
|
definition of. 217 |
|
|
macio 340 |
of cblorine, 248 |
|
myrlstic 313 |
|
|
nitno 2SS 235 |
Tolunietrio estimation of ofli- |
|
mine dilnte, 236 |
oiai, 443 |
|
mtiobrirochbrlo. !46, 230 |
Acidulous vndioala, qaalitatiTe de- |
|
d Inte 140, 230 |
tection of, 300 |
|
nitromuniitio, 286 |
radioals, quantitativ* estima- |
|
mtrous 288 |
tion of saUa of, 474 |
|
cenanthjho 373 |
radicals, tables to aid in tbe |
|
oleic 8 1 |
dele ton of 3(2 803 |
|
oiolio 2 1 |
ActdiiT, afil cum ■>48 |
|
palmit 0 3 3 |
a el cum n pan! es n 497 |
|
pelargonii, S73 |
acet UB dlutum "if |
|
acilcunjl ale 24 |
|
|
ace/ u gUn ah n pur lies in. |
|
|
phenio 363 |
49 |
|
phosphowo 26, 271, 280 |
|
|
dilute 271 |
berno U7> 27r |
|
pliosj horons, 289 |
boracc pur t as a 497 |
|
carbol c n 3b8 |
|
|
llZin |
chTon eum 193 |
|
poijgallie 290 |
|
|
propionic 373 |
c incum impur t es in 497 |
|
in.3810 230 |
gall am 2J6 |
|
pyrogiliio 298 |
gall cum n pur t ea n 497 |
|
pycohgaeous, 245 |
lylochlo-icu 2r >> (1 |
|
pjiophosphoric, 288, 289, 230 |
kjlolU, cum rapurtes in, 49 IjiocM c mdmam 220 |
|
"aeolinno 340 |
|
|
Bihoio 291 |
hyd oc/a c m 1 lutum 230 |
|
Btenrc 8 0, 373 |
%rf ocya teua dilitt m. mpuri- |
|
tea n 49 |
|
|
Bulphocjnmc, 298 |
nttncum. 235 |
|
sulphuric 204 |
mincum mpont es n 497 |
|
Bulphuiio aromotic, 250 |
/ JM „ 36 |
|
dilute 256 |
lat « |
id, Google
nifro-muriodciiJJi, 236 oxalietaa, impurities in, 497 phoiphoricum dilultim, 271 plioephorkum diluium, impuri- ties in, 497 lulphurieum, 256 mlphwicum, impurities In, 468 sulphmienm aroTnaticum, 25G tulphtricum diluium, 256 tulplaa-osioa, 258 Kulphuraium, impudties in, 490
tannicam, inipnrities in, 498
tartaTieum, 2S4
tartaricvm, impurities in, 498
valerianieum, 299 Acomii folia, 325
radix, 825 Aamiiia, 825
impurities in, 498 Aeonilina, 325 Aconitiue, 325 Aconitum napdlus, 325 Acrolein, 365 Adept bemoalus, ill
prceparatiii, 871
prreparaiua, impurities in, 498 ^U Marmelos, 295 Aerated bread, 337
water, 60 ^Iher, 891
foi-lior, 353
impurities in, 498
ptirtia, 353
Buriia, impurities in, 498 ABiaity, chemical, 33 Agate, 201 Air, GomposiUon of, 23
Influence of animals and plants on, 13
nitrogen in tlie, 22
oxygen in tlie, 15
relative weiglit of tlie, 23
■weight of 1 cubic cent,, 431
weigbt of 100 cub. inch, 431 Albumen, 366
vegetable, 368 Albumen ovi, 366 Albomenoid substnnces, SS6 Alchemy, 13 Alcohol, 347
AkoJiol —
absolute, 848, 414
amjlic, 361, 414
butylio, 299
cinnamic, 382
diluttim, 348
elbjlic, 348
fortius, 347
in 100 paris of spirits of dif- ferent densities, Table show- ing the proportion of, 506
me thy lie, 357
phenio, 363
quantitative estimation of, 493
radicals, 356
real, 348
test for impurities in, 498
test for parity of, 447 Alcohol araylicum, 361
amylicum, impurities in, 498 Alcoliols, 355 Aloohometer, 427 Aldehyd, 349
euodio, 377
Ifturio, 377
Aldehyds,' 356 Ale, 385
Alexandrian senna, 341 Algaroth's powder, 140 Aiiiarin, 384
Akalies, anatydcal separation of the, 73
438 Alkalimetry. 442
Alkaline carbonates, volumetric es- timation of tlie, 438
earths, 96 Alkaloids, 315
antidotes to the, 317
nomenclature of, 316 Alkanet, 384 Alkanna tincloria, 384 Allium, 368 AUotropio bodies, 334 AUotropy, 334 Alloy, 155
Alloys, nnnljais of, 311 Alljl, 364
sulphide of, 364
sulphoeyiinate of, 3G4 Almond-oil, 372 Almonds, oil of bitter, 341, 3G3
id .y Google
512
Alot tarbademii, 310
locolTtna, 840 Aloeresinio acid, 340 Aloerelialo acid, 840 Aloes etic aoid, 310 Aloin, 340
potash-, 103
Boda-, 102 Alamen, 102
impurities in, 493
txaiecaliim, 103 Alumiaa. 103 Altunlnlom, 102, 466
analytical reactions of, 103
andatnmonium, sulphate of, 102
bronze. 102
derivation of word, 28
oiide of, 103
qnantitatiie estimation of, 466
Biticste of, 102
sulphate of, 103 Amalgam, 165
aramomum, 65 Amber, 3^2
oil of, 302 American EeaniL, 342
turpentine, 377 Amido-chlocida of mercury, 163 Amines, 316 Ammonia, 64, 65
fetid spirit of, 67
f;as, composition of, 66
preparation of, 66
solution of, 66
Bolution of sulphide of, 69
Toloanio, 66
volumetric estimation of solu- tions of, 438 Ammoniaaal liquor, 65
salts, soarces of, 64 Ammooiacam, 381 AmmoHia acslatia liquor, 66 >, tpiritus, 67
beitmiK, impurities in earbonas, 67 carbonai, impurities
Ammomx —
f<stidus, apirilUE, 67 fortior, liquor, 66 liquor, &i tiiui-ias. 65
sulpha), 65 Ammoniated mercury, I Ammonii bromidum, 68
-ferric sulphate, 103 -Gitrato of BilTsr, 136,164 ■f copper, 137,
-sulphate of magnes
e of ii
1,115
m, 4S1
Ammoni-um, 64
acetate of, G6
-amalgam, 65
analytical reactions of, 70 .
and platinum, double chloride
■of, 71, 202 arseniate, 131 bicarbonate, 67 beozoale of, 68, 277 bromide of, 68 carbonate of. 67 chloride of, 65
e of, y
n of word, I
iialate of, 6
of, f.
! odium, sepa- ration of, 73
quantitative estimation of, 462
salts, Tolatility of, 03
sulphate, 65
sulphide of, 69
Eulphydrate of, 68
tartrate of, 72
Tolumettio estimation of car- bonate of, 438 Amorphous, meaning of, 144
phosphorus, 334 Amygdala amara, 341, 872
dukis, 341, 372 Amygdalin, 841 Amy], 356
acetate of, 862
id .y Google
|
INDEX. |
||
|
Amyl- |
Analytical reactions o |
|
|
Tiilerianafe of, 302 |
BaiJmium, 204 |
|
|
Amjlfl«Boua substances, 381 |
caffeift, 329 |
|
|
Amylamiiie, 316 |
caluium, 85 |
|
|
Amjlio alcohol, 361,414 |
carbonates, 259 |
|
|
Amylum, 331 |
chloriiles, 243 |
|
|
impuriiies in, 498 |
chlorides, 222, 889 |
|
|
Analogy of salts, 62 |
Ohromotes, 193 |
|
|
Analyeis, 72 |
chromium, 194 |
|
|
blowpipe, 30 |
citrates, 269 |
|
|
gas-, 296, 318 |
cobait, 189 |
|
|
graTimetrio, 410. 457 |
conia, 828 |
|
|
meaning of word, 42 |
copper, 151, 387 |
|
|
organio, 485 |
cyanides, 231 |
|
|
proximate, 485 |
ferric salts, 132 |
|
|
qualitatiia, 72 |
ferridcyanides, 281 |
|
|
quaotitotiTe, 409 |
fcrro cyan i das, 280 |
|
|
speotrum-, 813 |
ferrous salts, 121 |
|
|
and synthesis, 42 |
fluorides, 281 |
|
|
formates, 279 |
||
|
and separation of the |
gallic acid, 296 |
|
|
tals, 73, 93, 124, 145 |
148, |
glucosides, 840 |
|
177, 210 |
gold, 200 |
|
|
ultimate, 185 |
gnaiaoin, 344 |
|
|
Tolnmetric, 410, 436 |
||
|
of gases and vapors, 813 |
bydroeyanie neid, 231 |
|
|
of insolnblc salts, 311 et |
uq. |
hypocbloritas, 241 |
|
bypophosphites, 283 |
||
|
of salts, 300 |
hvpoBulphitea "85 |
|
|
of sublanoes ha»mg UDkaown |
||
|
properties, 312 |
||
|
Analydcal chemists, 14, note. |
||
|
detection of the acidulous |
radi- |
8 |
|
cals of salts aolulilc in water, |
||
|
800 |
m g 0 |
|
|
memornnda, 212, 219 |
||
|
Analytloal reactions of |
m |
|
|
acetates, 247 |
m 892 |
|
|
e 3 |
||
|
alcohol, 349 |
m 5 |
|
|
aluminium, 103 amygdalin, 341 |
pb 8 |
|
|
m |
||
|
aQtimony, 148, 887 |
||
|
fttropio, 826 |
||
|
barium, 76 |
9 489 |
|
|
beberia, 327 |
ph ph 2 |
|
|
bensoates, 277 |
ph ph 290 |
|
|
berberia, 327 |
p om 2 2 |
|
|
bismoth. 203 |
p m 53 |
|
|
borates, 275 |
p g d 296 |
|
|
bromides, 223 |
p ph ph 90 |
|
|
bmcine, 824 |
q |
id, Google
|
614 IHD |
EX. |
|
Analytical r&actlons of— |
Antldotea to— |
|
saliciD, 345 |
antimony, 145 |
|
BiliC!iteB. 292 |
|
|
eilvev, 178 |
harium, 76 |
|
sodium, 68 |
carbolic acid, 861 |
|
starch, 332 |
copper, 153 |
|
hydrochloric acid, 222 |
|
|
atryohDin, B24. 391 |
hydrocyanic acid, 233 |
|
Buooinataa, 298 |
lead, 172 |
|
BUgHT, 836 |
mercury, 168 |
|
sulphates. 266 |
nitric acid, 239 |
|
sulphides, 251 |
osnllc acid, 262 |
|
silver, 177 |
|
|
sulphuric acid, 257 |
|
|
Bulphario aeid, 389 |
tin, 199 |
|
tannic acid, 294 |
jino. 101 |
|
tartrates, 266 |
Antimouial wine, 111 |
|
theia, 829 |
Antimoniate of Sodium, 68 |
|
tin, 197, 108 |
|
|
nratfls, 297 |
Antimonic anhydride. 111 |
|
veratria, 839 |
Antmonii chleridi, liquor, 141, 4S9 |
|
lino, 100 |
OXidam, 140 |
|
Anchusa tinctoria, 381 |
oxidum, impurities in, 498 |
|
Anchaain, 884 |
et polaaice tarlraa, 141 |
|
Aogelic acid, 376 |
oxyatdphuretum, 142 |
|
Angelic powder, 140 |
talpkurelani, 142 |
|
Angmtura, 331 |
|
|
Angusturin, 831 |
Antimomiim niffrum, 139 |
|
Anhydrides, 59 |
nigram, impurities in, 498 |
|
acetio, 246 |
sulphur attim, 142 |
|
antiiBonie, 140 |
tartaratum, 141, 214 |
|
antimonious, 140 |
tarlaratiim, qaantitative esti- |
|
crD-bonic, 258 |
mation of antimony in, 468 |
|
nitrio, 288, 286 |
Antimony, 128, 139, 263. 416, |
|
nitrous, 238 |
168 |
|
phosphoric, 22, 85, 287 |
analytical reactions of, 143 |
|
Bxlphudc, 256 |
and arsenic, analytical separa- |
|
tion of. 146 |
|
|
Anhydrous bodies. 59 |
ftom arsenic, to distinguish. |
|
nitric acid, 236 |
135 |
|
sulphate of copper, 151 |
and potassium, tartrate of, 141 |
|
Aniline, 364. 385 |
264 |
|
colors, 885 |
antidote to, 116 |
|
Animal eharooal, 82 |
black, 139 |
|
rouge, 384 |
butter of. 140 |
|
chloride of, 139 |
|
|
acdon of air, 18 |
crude. 139 |
|
Aniseed-oil, 875 |
derivation of word, 28 |
|
Anise, 375 |
in organic mixtures, detection |
|
AnthtmidiS fioTM, 831, 876 |
|
|
Anthimii nabUis, 376 |
oside of. 140 |
|
Anthracite, 195 |
osyohloride of, 140 |
|
Antichler, 258 |
oxyaulphide of. 141 |
|
AntiaoteB to alkaloids, 317 |
pentaohlorlde of, 140 |
id, Google
Antimony- quantitative estimntioa of, 468 Eolutiou of ohloride of, 140,
sulphide of, 139, 143
sulphur Bftlta of, U2
Eulphumted, 111
tartarated, 141 Anttsepdo, 364 AotozoDe, 193, 402 Apomorpbia, 309 Aporetine, 277 Apparatus, vii
for volumetrio aBaljeia, 436
arbonici, 258 ,63 forlior, e,S
anethi, 375
tairantiifiorU, 376
ii«r(Hi(t'iJ?o™, impurities i
cainphara, S7S
eMorinii, 221
crefUDti, S64
dettiUala, 96
dalillata, impurities in, ■
forti), 236
louroceraH, 841
menlhce j/iperila, 375 »iri<Ss, 876
regia, 146, 236
roire, 876 Arabin, 84 AracMdio acid, 373 ArboT Dian^, 176 Archil, 384 Are, 419 Argal, 268 Argmli eyanidum, 176
nitTOi, 175 ■
nitrai. Impurities in, 408
oxidam, 175
oxtVJum, impurities in, ii Argentiferous gnleofl, 174 Argmtum, 29, 17G Argeatwi puTificatum, 176
purificalvm, impurities ii Ai^oi, 263 Armenian bole, 364 ArmoraciiB radix, 375 Arniitto, 384 Arnica, 880 Arniac radix, 380
Aroioin, 380 Arnolto, 884 Arronroot, 832 AiBenliitea, 1
, SClUtioQ
la of, 132
□Leal solutions, volu- '
anhydride, 180
odor ot, 130
)q carbonate of potassium, solu- tion of, 129
in hydrochloric ai of, 129
white, 128 Arsenical ores, 128
sulphur, 136 ATimici iodidum, 128 Araenlcnm, 128
analytical react
antidotes to, 13'
and antimony, analytici ration of. 146
bromide, 138
chloricle, 128
deriTation of word, 28
from antimony, to distinguish, 135
detection of, in organic mix- tures, 387
Pleitmann's test for, 135
hydride of, 134
iodide of, 128
Marsh's test for, 133
quantitatiTe estimation of, 449 468
Beinsch's test for, 183
souroaaof, 128
sulphide of, 129, 135 Arsenide of cobalt, 189 Arsenic-sulphide of nickel, 190
id, Google
silver, 137
godium, ISl Arsenuretted hydrogen, 134 Art of ohemiBttj, 13 Ash, 74
black-, 62
bone-, 82
soda-, C2 As'i?^, aoalj'sis of (mixed Eolids),
308 Asparegtn, 287,814 AssafcEtida, 381 ' -ate, meaning of, &2 Atmosphere, carbonio acid in, 259
composiUon of, 23
nitrogen in, 22
Barium, 75
acetoiiitrnte of, 05 analytical reactions of, 7i and calcium, sepnratioi
from magnesium, 03 carbonate of, T5 chloride of, 7o ohromate of 76 derivation of word, 28
I, 15, 23
I, 156, 158
875
oxygen i Atomic proportioi
theory, 36
freights, 37 Atomicity, 39 Atoms, SO, 37
impurities in, 408 AtTopiee, salphas, 326
tuiphaa, impurities Atropine, 326 Altar of rose, 377 Aiirania
amari coHex, 375
duleis cortex, 375
flora, 876 Anrio chloride, 200
Bael frmt, 295 Baking powder, 337 Balance 417 Balloons, coal-gns for, 21
hydrogen for, 21 Balm-of-Gilead fir, 881 Balsam, Canada, 38 1
oopaiTS, 380
fir, 377
Peru, 382
Storas, 382
Tolu, 882 Bahamum Peruviarfum, 882
PtTuvianiim, impurities it Tolufanum, 382
cium and magnesium, i
nitrate of, 75
peroxiiie of, 76
quantitative estimation, ^
salts, antidote to, 76
sulphate of, 76
sulphide of, 76 Barley- sugar, 339 Baryta- water, 76 Bari/tJE cai-bonaSf 75 Basalt, 102 Base, meaning of, 219
organic, 316 Basic, moaning of, 161 ■
BauxHe, 102 Bay rum, 847 Bearberry, 205 Beaver, 380 Bebaia mlphai, 326
sulphas, impurities in, 40f Beberia or beberinc, 826 Beer, 338 BeUsfructus, 205 - mdonniB folia, 326
radix, 326 Bel) -metal, 196
d glass tubes, to, 16
Benzonte of ammonium, 67, 2'
d lard, 371 Benzoates, 276
otd, 276,414,415
276, 382
1, 276, 382 Benzol, 363, 114 " loyl, hydride of, 341, 382 Berberia or berberine, 327 Bergamot oil, 370 Berlin blue, 385 red, 884 ■ Berryliiuni, 507 Bi-, the prefix, 48 Bibasio, vide Dibasic
id, Google
|
Dihulniis pnpfir, SI |
Blood root, 329 |
|
Bicarbonate of potassium, 48, |
Bloodroot Tinegar, 245 |
|
265, 269, 438 |
Blood-stains, 402 |
|
of sodium, 58, 265, 269, 438 |
Blowpipe-analysis, 808 |
|
-flame. 808 |
|
|
Bile, 371 |
Blue coloring-matters, 884 |
|
Biliary calculi. 406 |
copperas. 107 |
|
Bismuth, 205, 416, 428. 469 |
indigo, 239 |
|
and uTDRioniuiii. eoludon of |
ointment, 154 |
|
citrate of, 207 |
pill, 154 |
|
analj'tioal reactions of, 208 |
stone. 151 |
|
carbonate of, 207 |
iiitriol, 107, 151 |
|
derifntion of word, 30 |
Boiling-poiuta of various sub- |
|
-lozenge. 206 |
stances, 414 |
|
nitrate of, 205 |
■'Bonds" (Franklaud), 102 |
|
quantitative estimation of, 469 |
Bone-ash, 62 |
|
-salts, compositioQ of, 206 |
-black. 82 |
|
Bubnitrata of, 206 |
Boracic acid, 274 |
|
sulphate of, 207 |
Borates, 274 |
|
Bhmutki carbonai, 207 |
analytical reactions of, 275 |
|
Borax, 274 |
|
|
math in, 469 |
impurities in, 498 |
|
carboaai, impurities in, 498 |
Tolumetric estimation of, 440 |
|
auiMj ion-K, 207 |
Borai bead, 187 |
|
luhmlrai. 208 |
Bordeaux turpentine, 377 |
|
Ba>aulk»,m, 205 |
Bornebne. 378 |
|
PHnJicatvin. 205 |
Boron, 275 |
|
chloride of, 275 |
|
|
Bieulpbide of carbon, 356 |
derivation of word, 29 |
|
Bitter almonds, oil of, 341, 363 |
fluoride of. 275 |
|
principles, 330 |
Borotartrate of potassium, 275 |
|
Bitniuiaous coal, 105 |
iJoj/BHr«j. 871 |
|
Bivalencc, 39 |
Brandy, 350 |
|
Biyaleut radicals, 39, 44, 92, 95 |
Brass. 96 |
|
Bixa, orillana, 361 |
Brasil wood, 384 |
|
BiMn, 88* |
Bread, 331, 837 |
|
Black-ash. 62 |
making, 337 |
|
-band, 105 |
Btenilin, 384 |
|
coloring-matters, 8R3 |
Britannia metal, 139, 167, 196 |
|
dyes, 885 |
British gum, 333 |
|
bydratoof iron, 119 |
Bromate of potassium, 52 |
|
ink, 123, 295 |
Bromates, 52, 244 |
|
-lead. 26 |
Bromio acid, 52, 244 |
|
oxide of copper, 152 |
|
|
oxide of iron, 119 |
arsenicum, 128 |
|
pepper, 829 |
iron, 110 |
|
Black oak, 383 |
poLiasium, 62, 223 |
|
Bladder-green, 885 |
potassinm, vol n metrical esti- |
|
Blanc dt Pc--U, 206 |
mation of, 446 |
|
Bleaching by chlorine, 25 |
Bromides, 223 |
|
■powder, 84 |
analytical reactions of, 223 |
|
Blende, 06 |
qaantitative analysis of, 446, |
|
Blood, 367, 402 |
475 |
|
hydrocyanic acid in the, 233 |
id, Google
518 INI
Bromiae, 223
aii:ilytic!iil aepnrfttion of, 224 derJTrttion of word, 39 KQlution of. 223 volumetric e^timutioa of free.
Bromtnium, 223 Brontvm, 223
impurities in, 498 Bronze. 196
coinage, 150
nlumiaiura. 102 BroDzing-powder, 198 Sroom-tops. 329 Brown coloring- matters, !
hcematite, 105 Brucia, 324 Brucine, 82 J Brnn snick green, 13S Sac/fa folia, 331 Buchii, oil of, 376 Bucktbora-green, 386
-juice, 842 Bunsen gas-burners, 21 Burette, Mohr's, 436 Burgundy pitch, 380 Burners, gas-, 17, 2! Burnett's disinfecting fluii Burnt Gugnr, 339
uDiber, 385
Botjl, 299
snlphocjannte, 356 Butflio alcohol, 299 Butjratas, 209 Butyric aoid, 299, 374 By-products, 157
Cocno oil, 372 Cadmii iodidam, 204
iodidum, impurities in, 499 Cadminm, 203
analytical reactions of, 204
carbonate, 204
derivation of word, SO
iodide of, 204
nitrate, 204
eulphnte, 204 Catalpinia iraji'Jimra, 384 Cteeium, 507 Cfttteia, 329 Cftjuput oil, 876
Calamine, 96 Calcii chloridum, 78
chloridam, impurities in, 49 Calcined magnesia, 89 Caldt carbonas praicipilala. 80
carbonas praxipitiila, impurii ■ I, 499
eklora hjdru.
0^,84
phosphas, 82 pho^phas, impurities satchaTatus, ligxior, 8i
Caloium, 78
analytical reactions
prepared, 88 chloride of, 78 ehromata of, 85 derivation of word, 28
fluoride of, 78
gummate of, 84
hydrate of, 79
hypochlorite of, 84
hypophosphile of, 2R2
hyposulphite of, 250
in presence of hariam and magnesiam, deleetiou of, 93
phosphate of, 78, 82
polysulphide of, 250
quantitative estimation of, 464
silicate of, 78, 201
sulphate of, 78, 85, 251 Calo-spar, 78 Calculi, urinary, 404
Calomel, 154, 159
L of, 404
Calvmbie radix, 327 Calx, 79
impurities in, 499
chlOTinata, 84
chlorata, 84
cklorata, impurities ii
of, Ifil
id .y Google
C ad h Isam 381
Oanlh is 378
C t h 882
C p ty t 419
C p U y 412
C p t f glv jl 373
C p d 373
C p jl 85&
Caprjial* of glyceryl, 372
Caprylio aoid, 373
Gipsicifrucim, 327
Cnpaloia, S2T
Cdpeu
1, 827
Capsicum, oi
Caramel, 336
Cftrftway oil, 876
Carbolic aciii, 303, 414, 416
Carbon, 26
bisulphide nf, 356 combustion of, 26 derivaUoo of word, 27 quaotittiti ve esti mation of, in or- ganic compouads, 4g6 et leq.
Oarbo anitaalit, S2
animalU pwificaiui, 82 animalii pur^eai'ui, impuiitiee in, 499
ligni, impurities In, 49S CailiODate of amraomuni, 67 bismuth, 267 cadmium, 204 calcium, 78, 80 caloium, prepared, 82 iron, 107. 452 iron, saceharaUd, 108, 452 lead, 163 lithium, 183
Carbonate of—
magoesLittn, 83 potsssiuio, 42, 438 potiiEsium, acid, 47, 438 sodium, 66, 62, 258, 438 sodium, acid, 58, 438 zinc, !)6, 98
Carbonates, 2S8
Bciduloua radical in, 44, 258 acaljtioal reactions of, 259 gravimetric estimation of, 479 TQlumelrio estimation of alka- line, 438
Carbonic acid, 26, 258 anhydride, 258 generation of, 48
Carbonio aoid gas, solubility of, ia water, 60 oside, 280
Carbonization, T4
Cardamom oil, 378
Cardattiomum, 876
Carmine, 277
Carminic acid, 277
Carthamin, 3S4' Carthamus I
Cam
; 376
Carvol, 378 CaryopLyllin, 376 Cascarilla oil, 370 Caacaritla cortex, 876 Casein, 367
vegetable, 368 OaJJi'a marilaiidica, 373 Cassia oil, 3T6 Caaaiie pwlpa, 537 Cast-iron, 105.418 Castor, 380 Cotter fiber, 380 Castor oil, 372 Caaloreum, 380' Castorin, 380 Catechu, 295 Catechu pallidum, 295
pallidum, impurities i Cathartic acid, 341 Cathartogenic acid, 312 Const; a, 175
lime, 80
id .y Google
|
520 INDEX. |
|
|
Cedrn oil, 3T6 |
Chemic^l- |
|
CekstLn?, 184 |
formulie, 34, 8S, 37 |
|
Cellulin, 3S5 |
Dotation. 84, 35. 37 |
|
CelluloBB, 335 |
preparations of the Pharma- |
|
Celsius's thermometer, 413 |
copceias, 409 |
|
Cera en la, 291 |
symbols, 34, 36, 87 |
|
Ccntmrc, 419 |
toxicology, 386 |
|
Centigrade thermomotcr, 413 |
Chemicals, 14 |
|
CernBio, 888 |
Ciiemistry, artof, 13 |
|
Ctralumpl«mbi suiacelalia, vide Uii- |
|
|
guenlum |
tween, 37 |
|
linti earbonaiii, 99 |
derivation of the word, 13 |
|
Cera alia, 372 |
inorganic. 315 |
|
Blba, inipuritiea in, 499 |
object of, 14, 87 |
|
;ft<™.372 |
organic, 315 |
|
fiava, impuritiea in, 499 |
science of, 13 |
|
Cerebriii. 367 |
Chemists, analytical, 14 |
|
Ce™«-« ftm«i(«m, 347 |
manufacturing, 14 |
|
Cernoxalaz,\»b |
pharmaceutical, 14 |
|
taalat, impuriOes in, 499 |
ChenopoSi-am, 378 |
|
Cermm, 185 |
Cherry-laurel water, 841 |
|
Cherry-tree gum, 838 |
|
|
oiulnteof, ]85 |
Chestnut-brown. 385 |
|
Cerolein, 872 |
CbiiD turpentine, 870 |
|
Cerolic acid, 373 |
Chilli ophila. S31 |
|
Cataceum, 872 |
Chinese red, 384 |
|
imparities in, 499 |
yeilow, 383 |
|
Cetene, 372 |
Chmila, 331 |
|
CetTaria. 277 |
Chloral, 360 |
|
Cetraric acid, 277 |
|
|
Cetyl, hjdrate of. 372 |
|
|
palmitste of, 372 |
gen from, 16 |
|
Cliakedonj, 291 |
Chlorates, 241 |
|
Chalk, 82 |
analytical reactions of, 243 |
|
preoipilaled. 80 |
Chloric ncid, 240 |
|
prepared, 82 |
|
|
-stones. 446 |
antimony, ISO ■ |
|
Chaljbeale -vrnter, 105 |
arsenicum, 128 |
|
Chameleon, minernl, 187 |
barium. 75 |
|
ChatBomile oil, 87& |
boron, 275 |
|
Clinr. 74 |
calcium, 78 |
|
Charcoal, 26 |
calcium, removal of iron from, |
|
animal, 82 |
78 |
|
Kood, 83 |
lead, 171 |
|
Cheese, 367 |
lime, 84 |
|
Chemical action hy symbols, illus- |
magnesium, 87 |
|
tration of, 34 |
manpneEe, 186 |
|
affinit;, 32 |
m.rcury, 158 |
|
combination. 38 |
platinum and ammonium, 71, |
|
oomhination different from me- |
462 |
|
chanical, 26, 33 |
platinum and potassium, 54 |
|
silicon, 292 |
|
|
288, 409, 467 |
silver, 174 |
id, Google
|
INPEX. 521 |
|
|
ChloriJes, 219 |
Cliichoim:-^ |
|
teats for, 222 |
rubra: cortex, 320 |
|
eatimatioo of, 474 |
CiQOhoria, 3o7 |
|
Chlorinated lime, Tolumetrle esti- |
Cinehomm sulpha,, 322 |
|
mation of, 464 |
|
|
soda, solution of, 61 |
Cinobonioine, 323 |
|
Cinchonidia, 823 |
|
|
464 |
|
|
Chlorine, 24, 219, 488 |
|
|
acids, 248 |
Cinnabar. 153 |
|
as a disinfectant, 25 |
Cinnameiu. 382 |
|
Weoching by, 25 |
Cinnamic acid. 882 |
|
collection of, 24 |
alcohol, 382 |
|
derivation of word, 27 |
Cinnamomi cortex. 376 |
|
properties of, 24 |
Cinnamvl, hydride of, 382 |
|
relative weiglit of, 26 |
Cissampelia, 327 |
|
Cissampeline, 327 |
|
|
water, 24, 221 |
|
|
Cliloroohromio acid, 194 |
|
|
Chloroform. 869, 414 |
of iron 116 |
|
ro and qu ue 117 S'O 490 |
|
|
Ghloropbjtl, 889, 408 |
Ithun 11 |
|
Chocolate, 372 |
na PS un ''8 |
|
Cholalio acid, 371 |
|
|
Cholate of sodium. 871 |
p 1 u 49 |
|
pota u V 1 mHr est ma |
|
|
Chondrin, 388 |
t f 4 ' |
|
CAondru, crispas, 333 |
of miK e urn "Xii |
|
Chromalfl of barium, 73 |
0 trates (i |
|
calcium, 85 |
anal3 teal react ons of "69 |
|
lead, 172 |
volu et c eat mat on of 488 |
|
potaasiura and ammonium, 77 |
C tr c ac 1 b |
|
potassium, standard Eolution |
satu at ug power of 69 |
|
of red, 451 |
666 |
|
Cliromatefl,193 |
L tron 0 1 376 |
|
analytical reactions of, 198 |
r 1 0 ta tnrate of b 1 un f." |
|
of potassium 76. 192 |
tl a fieat on of el m ut 4 9 |
|
Chrome-ironstone, 192 |
94 21 |
|
-red, 172 |
Clay 10 m |
|
-yellow. 172 |
ronstone 10 |
|
Chromic acid. 193 |
Cloves 0 i r 3 8 |
|
anbydride, 103 |
Cluh-moaa, 373 |
|
salts, 192 |
Coal, 195 |
|
Chromlam, 192 |
praduota of, 356 |
|
analytical reactions of. 104 |
-gas, 356 |
|
derivation of word, 30 |
-gas for balloons, 21 |
|
Cbromous salts, 192 |
Cobalt, 189 |
|
Chromule, 885 |
analytical reactions of, 189 |
|
Cbrysopbanio acid, 277 |
arsenide of, 189 |
|
blue, 884 |
|
|
Cioutine, 328 |
derivation of word, 30 |
|
dmhanrnfimiK coHex, 360 |
-glance, 189 |
|
p-aiidm cortex, 820 |
Cobaltic ultramarine, 384 |
id, Google
|
Cooio, cotiine, or oonioine, 328 |
||
|
C00CU4. 277 |
Coniifoba. 828 |
|
|
Cocliineal, 277 |
||
|
Codoa Diba, 372 |
Constant proportions, law of, 86 |
|
|
Cocoa nut, 872 |
||
|
Coooa-Qutoil, 872 |
488 |
|
|
Ooroa nuci/era, 372 |
Gonstitiitlon of alkaloids, 815 |
|
|
CodeiH, 319 |
salts, 39, 91, 217, 234, 247 |
|
|
Coil-liver oil, 872 |
lialble matter, 33 |
|
|
Coinage, copper, 150,428 |
ConTolvulin, 344 |
|
|
gold, 199, 428 |
||
|
BilTer, 174, 428 |
Conylia, 828 |
|
|
Coke, 26 |
Copaiba, 380 |
|
|
Oakhiei cormuf, 829 |
||
|
Copaiva, 380 |
||
|
Colohioia, S29 |
oil. 380 |
|
|
Copoivic acid, 3S0 |
||
|
Colohicani yinegar, 245 |
Copper, 140 |
|
|
Colcothar, 884 |
acetate of, 151 |
|
|
Collection of gases, 16, 17 |
ammonio-solpUate of. 187. 153, |
|
|
Collin, 494 |
164 |
|
|
Collodion, 385 |
analytloal reactions of, 151,388 |
|
|
Colladium, 335 |
antidotes to. 158 |
|
|
flmie. 885 |
arseniale of. 137 |
|
|
Colloid bodies, 494 |
||
|
Colocynthidis pulpa, 342 |
arsenite of, 187 |
|
|
Coloeyiithin, 342 |
black oside of, 150 blue, 384 coinage, 150, 428 derivation of word, 28 detection of »rsenii:um in, 1S3 foil, 150 |
|
|
83 |
bydrate of, 162 |
|
|
34 |
in orgflnie mixtures, detection |
|
|
m g |
;3, 156. |
melting-point of, 416 oiyacetate of, 151 |
|
m |
pyrites, 140 quantitative estimation of, 469 |
|
|
i Lydro- |
EubBoetate of, 151 ^ulpUate of, 151 |
|
|
488, 487 |
sulplinte of, nnlijdrouB, 161 Copperas, blue, 107 |
|
|
m |
ItB, 206 |
green, 107 Ooptis trifoiia, 327 Coriander oil, 876 OoHandruvi, 376 Cork-borers, 16 |
|
S |
Correction of the volume of a gas |
|
|
for pressure, 430 |
||
|
ds, 53, |
for temperature, 430 Corroaivo Buhlimale, 154, 158 Cotton-wool, 3^6 |
id, Google
|
INDEX. 523 |
|
|
Cows' milk, 367 |
Ilnlton's atomic theory, 30 |
|
Cream. 368 |
Daphne laureola, 880 |
|
Cream of tartar, 264, 488 |
mizereura, 380 |
|
CreasoW, 363 |
Daturia or daturine, 326 |
|
a-eaeotum, 363 |
Dauglish'H bread. 337 |
|
impurities in, 499 |
Davy's safety-lamp, 21 |
|
Crda, 82 |
Deadly nightshade, 320 |
|
Decantntion, 31 |
|
|
Crocus (mineral), 115 |
Decimal weights, 418, 420 |
|
(vegetable), 383 |
Decoctions, 407 |
|
Crocus laliPUS, 383 |
Decrepitation, 307 |
|
Croton oil, 372 |
Deflagration, 51 |
|
Ci-otonate of gljoerjl, 372 |
Deliquescence, 62 |
|
CruoiblcB, 46 |
Density, 425 |
|
Cryolite, 311 |
of vapors, 431 |
|
Crjstalliintioa, water of, 59 |
Deodorizers, 25 |
|
Crystalloid bodies, 494 |
Deodorizing liquid, 98 |
|
Cubeba. 829 |
Deposits, urinary, 307 |
|
Cubeb pepper, 329 |
Derivation of names of elements |
|
Cabebs, oil of. 376 |
27 s( ug. |
|
Cubic iocbea is 1 gallon, 431 |
Derivatives of ammonium, 164 |
|
Cudbear. 384 |
Desiccation, 468, 4fi0, 483, 484 |
|
Cupel, 473 |
Detonation, 51 |
|
DeValangin's solution, 129 |
|
|
473 |
De Vry's process for estimating Ihe |
|
Cupn sabofetaa, 161 |
purity of commercial quinine, 489 |
|
ivlpkat, Ibl |
Dextrin, 32 |
|
lulphat, impurities in, 499 |
Dextrose, 889 |
|
Cnprie compoands. 151 |
Diabetic urine, 337, 394, 492 |
|
Cuprous iodide, 161, 227 |
Diagrams, chemical, S4, 43 |
|
oxide. 151, 330 |
Dialysis, 494 |
|
Capnan, 28, 149 |
Diamond, 26 |
|
ammomatum, 152 |
Dibasic acids, 219 |
|
Curcuma Imga, 883 |
Dibasjlous radicals, 219 |
|
Curoumin, 384 |
Didymiuin, 507 |
|
Cords, 887. 868 |
Diethylamine, 316 |
|
and whey, 337. 368 |
Dietliylia, 316 |
|
Caapari/e eorttx, 381 |
Diffusion, 21 |
|
Gusparin, 331 |
Digitalin, 342 |
|
Cus30, 380 |
ZHgitalmum, 842 |
|
Cynnates. 278 |
Uigitaliretin, 342 |
|
Cyanio aoid, 278 |
Digilalh folia, 848 |
|
Cynnide of meroary, 229 |
Dill oil, 375 |
|
nickel, 191 |
DinitroBellulin, 335 |
|
silver. 176 |
Disinfectant, chlorine as a, 25 |
|
Cyanides, 229 |
Disinfectants, 25 |
|
analytical reactions of metal- |
Disinfecting fluid, Burnett's, 97 |
|
lic, 230 |
carbolic acid, 363 |
|
double, 229 |
Candy's, 63, 187 |
|
powder. 84 |
|
|
Cyanogen, 229, 475 |
Distillation, 95 |
|
Cyauurets, vide Cyanide |
destructive, 96 dry, 96 |
id, Google
|
624 |
INDEX |
|
|
Distillation— |
Elements— |
|
|
fpactionnl, 847 |
metallic, 15 |
|
|
DistHled vinegar, 'IM |
BOQ-metallic, 15 |
|
|
Dithionic acid, 284 |
symbols of, 27, 34 |
|
|
Dolomite, 87 |
symbols, atomic values, |
|
|
Uonovau's aolutioo, 163 |
weights of the, 507 |
|
|
Dorema a«^moniaam, 381 |
Elemi. 881 |
|
|
Doable oyanides, 2*29 |
Elm bark, 295 |
|
|
salts, 54 |
Bmetia, 328 |
|
|
Dover-B powder, 828 |
||
|
Draol.™, 421 |
Empirical formulse, 818 |
|
|
DracoHjl, 882 |
JCmplastra, 379 |
|
|
Dried alum, 103 |
Emplaslrum cerati aaponis, 246 |
|
|
Dnigs, 15 |
plumM, 170 |
|
|
Drying apparatus, 458, 480 |
463, |
plumbi iodidi, 170 |
|
484 |
Eniolsin, 341, 364 |
|
|
oils, 872 |
Emulsion. 381 |
|
|
463, |
Enemas, 407 |
|
|
484 |
English red, 384 |
|
|
blue, 884 |
||
|
Bulcamara, 329 |
Epsom salt, 87 |
|
|
Dumas' B hvpotLeais, 36 |
Eqaalions, 34 |
|
|
Dyads, 91 |
Equivalence, 39 |
|
|
Dj-eing, 104, 239 |
Equivalents, 506 |
|
|
Djnnoiic electricity, production of, |
Ergot. 380 |
|
|
97 |
Ergola, 380 |
|
|
Efgotin. 880 Erliingcn blue, 384 |
||
|
Earthenware, 391 |
Brytbroretine, 278 |
|
|
Earths, alkaline, 95 |
Erucic acid, 373 |
|
|
Eou de Cologne, 875 |
Eseria. 328 |
|
|
Ebonite, 382 |
Essence of aniseed, 875 |
|
|
Eabnlliifiuctus, 843 |
apple, 362 |
|
|
greengage, 362 |
||
|
melon 362 |
||
|
dtro- tartrate of sodium, |
62 |
mirbane, 363 |
|
potasli-water, 40, 460 |
||
|
soda-nater, 60 |
pineapple, 362 |
|
|
quince, 362 |
||
|
Egg, vhite of, 366 |
peppermint, 375 |
|
|
yolk of, 866 |
Essences, 375 |
|
|
Elieometer, 427 |
Esismlia aiihi, 375 |
|
|
menthfE piperil<E, 875 |
||
|
Elaterin, 843 |
Ksseutial oils, vide Oils |
|
|
EtateHam, 343 |
Estimation of weight, 417 |
|
|
impucities in, 499 |
Etching, 281 |
|
|
Elder-flower oil, 877 |
Ethal, 372 |
|
|
Electricity, produoUon of dyn 97 Elementary particles, 33 |
araio, |
Ether, 351 nitrous, 853 Ethereal salts, SC5 |
|
Elements, IS, 14,27 |
oil, 364 |
|
|
and tiieir compounds, 41 |
Etherol, 864 |
|
|
classification of, 74, 91, 94, 212 |
Ethers. 355 |
|
|
etymology of namsB of. |
7 |
Ethiops mineral, 165 |
id, Google
Ethyl, 348, 355
aoeUtH of, 348
biityrate.of, 363
hydrate of, 348
iodide of. 351
nitrate of, 353
lenantliylate of, 362
peIargoii;lte of, 8G2
aebdcate of, 362
Boberate of, 862
sulpbat« of, 348
zinc, 355 Etliylamine, 360 Ethylene, 364 Ethylia, 316 Ethylio aluoliol, 348 Etymol pyof names of elements, 27 Eud ouetry 313 Euge 0 no d 376 Eugen n 3 6 Eaodo aide! yd, 377 Euxniitliate of magnesium. 483 Eviporat on 47, 74, 458, 459 Eiaminat ons of tlie Pharmaceuti- cal 'Society of Great Britain, 14 ( rfe Prefatory matter) Eipl s ' '"
' 407
Extract I
Face rooge '77, 884 Falirenlieit's tliormometer, 413 Farina Iritici, 331 Fat- acids, 373
Fats nnd oila, compoEition of, 370 Fata, &o., to determine Uie m«l ling- point of, 415 analysis of, 493 Fatty bodiea, 370 Fd bavinum purificalum, 371
puTiJkatwa, impurities in, 499 Felspar, 312 Fennel oil, 376 FermentaOoQ, 837 Ferme»lum, 847 Fer rSduit, 120 Ferrate of potasHium, 106 Feni ttcetalia tinctxira, 113
arseniai, impurilies in, 499 carbonaa, 108 carbonai tacckarata, 108
1,499 pereklm-idi, liquor, 112 pernitTaiii, liquor, 120 peroxidum humidum, 114 peroxidum hydraium, 113 peroxidum kydral-am, impurities
in, 500 persulphatii. liquor, 112 photpkaa, 106, 109 pAosphas, imparities in, 500 poliisaio-larlraa, 116 pulms, 20 pyropkosphaa, 121 subcarhonai, 108 ju/pAas, 107 sulphas, impurilies in, 500
sulpias
I, 107
sulphureium, 109 Petric acetate, 113 chloride. III iodale, 244 nitrate, 120 oxide, 115 de, froi
oxalates, separation of, 310 oxysulphate. 107 pyrophosphate, 121 salts, 110 salts, analytical reactions of,
ia2 Bulpliocyar
123
id .y Google
|
Femdoyatiide of potaasii^m, 123. |
Fluorides. 281 |
|
281 |
Fluorine, 282 |
|
FeiTidoyanidea, 218 |
deriTutionofword, 29 |
|
Ferriaojiiiiogen, l:;3, 280 |
Fluor-spnr, 381 |
|
Ferracyatiide of potassiam, 228, |
Funiculi fructm, 375 |
|
27M |
Foil, copper. 150 |
|
Farrocyanides, 279 |
Food, analysis of, 496 |
|
rerrocyitnogeii. 123, 280 |
elements of, 868 |
|
EeiToso- ferric hyilrate, 119 |
boiY disposed of in the bodies |
|
03.Ue. 119 |
of animals, 894 |
|
rerrouB arseniate, 108, 452 |
Force, obemioal, 82 |
|
bromide, 110 |
Forge-scales. 119 |
|
carbonate, 107, 452 |
Formates. 278 |
|
chloride. Ill |
Formic acid. 278, 373 |
|
phosphnie. 109 |
Formulre. 34, 37, 488 |
|
salts, 106 |
construction of, 39, 43 |
|
Bidls. aoalyl^col reactions of. |
empirical, 348, 488 |
|
lai |
graphic, 102 |
|
sulpiiate, 106 |
rational, 348, 188 |
|
Bulphide, 109 |
Fousel oil, 361 |
|
Fen-um, 28, 105 |
Fowler's solution, 129 |
|
Ttdaetum, 120 |
|
|
tartaralum, 118 |
Frankineense, 381 |
|
Frankland'9 grnphio formulfo, 102 |
|
|
in, 467 |
Freezing-mixture, 252 |
|
tartaritum, impurities in, 600 |
French chalk, 335 |
|
Fibrin, 867 |
turpentine, 377 |
|
Togetable, 368 |
Fruit essences, 362 |
|
Meus, 337 |
Fiichsine, 386 |
|
Fig. 337 |
Fume -cupboard, 69 |
|
F^iii: ma,, 373 |
Funnel -tubes, 69 |
|
Filter, to dry, iG3 |
Fusel oil, 361 |
|
Pilteriog-paper, 8], 457 |
Fugibility of metals, table of the. |
|
Filters, 81, 457 |
4ie |
|
Filtrate, 93 |
Fusing-pointa of fata, 415 |
|
Fine gold, 200 |
Fustic, 383 |
|
Fire-clay, J58 |
|
|
Fire-damp, 356 |
Galbantim, 381 |
|
Filed oils, 372 |
Galena, 167 |
|
Flame, oiidiiiug. 308 |
nrgentiferoas. 173 |
|
redneing, 308 |
Galenical preparations of the Bri- |
|
structure of, 20 |
|
|
Flare, 371 |
Galla, 293, 204 |
|
Flaxseed, 372 |
Galactometer, 427 |
|
FlcitmaQQ'9 test for arseuioum, 138 |
Gallic acid, 295 |
|
Flexible collodion, 335 |
Gall of the OS, 371 |
|
Flint, 291 |
Gallon, 421 |
|
Flam liaei, 100 |
Gall-stones, 405 |
|
Flour, 881 |
Galvanic test for mercury, 166 |
|
Flowers of Sulphur, 249 |
Galvanized iron, 96 |
|
Gambir, 295 |
|
|
Fluoride of oalcium, 78 |
Gamboge, 381,383 |
|
boron, 276 |
Gambogio acid, 381 |
|
tulicDD, 292 |
Garancin, 384 |
id, Google
|
INDEX, |
|
|
Garcinia morel/a, 381 |
Glyceryl— |
|
Oarlic, esGential oil of, 364 |
palmitate of, 372 |
|
GaB-analysis, 296, 313 |
riciiioleate of, 372 |
|
-buroers, 16, 17, 21 |
rulatc of, 872 |
|
far balloons, qqM-, 21 |
Glycboltttes. 371 |
|
Gljoociue, 871 |
|
|
-lamp, 17, 21 |
Glycoooll. 371 |
|
Gases and vapors, analysis of, SIS, |
Glycol, 365 |
|
412, 430 |
Glycols, 865 |
|
collection of, 16, 17 |
Glycyl, 365 |
|
oorreotion of the Tolume of, 430 |
Glj/cyrrhiiiE radix, 833 |
|
for pressure, 430 |
OlycyiThizin, 339 |
|
for temperature. 430 |
Gold, 199 |
|
law of solubility of, in liquids, |
|
|
60 |
coin, 199, 428 |
|
specific graiity of, 429 |
derivation of word, 30 |
|
Oavliheria proeumtens, 3(i2 |
earth, 199 |
|
Oaultherio itciij, S62 |
fine, 200 |
|
Gelatine, 369 |
.ieivdlers', 199 |
|
fegelable, 333 |
|
|
Gentiana radix, 381 |
oehre. 383 |
|
German silver, 190 |
perchlorideof, 200 |
|
Ginger oil, 878 |
yellow, 388 |
|
Glacial acetic acid, 24S, 415 |
Goldthread, 323 |
|
Glass, 291 |
Gossypiuni. 335 |
|
liquor, 293 |
Gothite. 115 |
|
rods, 46 |
Goulard's cerate, 169 |
|
soluble, 292 |
CKtraol, 109 |
|
tubes, to bend, 16 |
|
|
tubes, to cut, 16 |
Graham's dialylic process, 4 |
|
tubes, to draw out, 81 |
lawof diffusiun, 21 |
|
Globulin, 367 |
Grain, 419 |
|
Gluoiaum, 507 |
Grains, 419 |
|
Glucose, 337 |
Gramme, 4!9 |
|
Glucosides, 840 |
relation of, to grains, 4 |
|
Glue, 369 |
Granali jTuaiis cortex, 295 |
|
Gluten and gluUn, 831 |
radicis cortex, 295 |
|
Glyceric alcohol, 364 |
Granite, 102 |
|
Glycerine, 170, 864 |
Granulated tin, 196 |
|
Glycerines, 364, 407 |
line, 19 |
|
Qlycirinum, 864 |
Grape-sogar, 836 |
|
impurities in, 500 |
Graphic formulie, 102 |
|
atidi carbolic,; 365 |
Graphite, 26 |
|
addigaUici, S66 |
Gravel, 397 |
|
addi lannici, 293, 365 |
Gmvimetrio analysis, 410, i |
|
amsli, 865 |
Gravitation, 417 |
|
boracii, 275, 3C5 |
Gravity, 417 |
|
Glyceryl, 864, 370 |
Gray powder, 154 |
|
oaproftte of, 872 |
Green copperas, 107 |
|
caprylate of, 372 |
iodide of Tuevcory, 155 |
|
pigments, 885 |
|
|
ianrate of, 372 |
Titriol, 107 |
|
myriatate of, 372 |
Greengage essence, 862 |
|
olente of, 370 |
Griffith's mixture, 108 |
id, Google
|
528 IND |
EX. |
|
Group testa, 21!! |
MydTaTyyri — |
|
Ouaioci lignum, 8*3, 314 |
chloTidtim mile, 1B9 |
|
retina, 343 |
cyanidam, 248 |
|
Guainoin, 844 |
iodidum ruln-um, 163 |
|
Ounmcum, resin of, 3^3 |
iodidum TubTum, impurities in. |
|
GuaiuretiD, 344 |
500 |
|
OuamrelJnic acid. 344 |
|
|
Qum-Maom, 84. 833 |
iodidum mride, impurities in, |
|
-arabic, 84. 333 |
600 |
|
-resins, 381 |
nitrate liquor. 157 |
|
oxidum rubrum, 160 |
|
|
Gummicacid, 333 |
oxidum Tubrum, impurities in. |
|
Gtm-cotton, 835 |
500 |
|
Gunpowder, 238 |
perchloridum, 158 |
|
Gattft peroha, 382 |
iubckloTid,m, 159 |
|
Gjpsum. 78 |
|
|
lulphoi, 167 |
|
|
Hfemotln, 307 |
mlphat fiar'a. 158 |
|
Hsematite. brnwn, 105 |
aulphoi, impurilies in, 500 |
|
red, 105 |
mlphuTilum cum lulphure, 165 |
|
Htematoxyli lignum, 295, 384 |
tulphm-eliim cum mlphure, im- |
|
MtemntoKylin, 295. 384 |
puTitivs in, 600 |
|
Hair-soyeraign. weight of Elie, 109 |
tulphurelum ruhrum, 165 |
|
Hnloid saKa, 385 |
|
|
Hanibro' blue, 384 |
Hydrargyrum, 29, 353 |
|
Hardoesa of wntar, 260 |
|
|
Heat, latent, 60 |
ammoniaium, 163 |
|
aoucce of, 16 |
ammoniatuiB, impurities in. |
|
Heavy carbonate of magnesium, 8S |
500 |
|
ram creta, 154 |
|
|
spnr, (5 - |
cum craa, impurities in, 500 |
|
wliite, 75. 385 |
Hydrated peroside of iron, 115 |
|
Heberden's inli, 123 |
|
|
Hectare, 420 |
calcium, 80 , |
|
Hellebore, 829 |
cetyl, 372 |
|
ffimidami radix. 279 |
glyceryl, 372 |
|
Hemidesmic acid, 279 |
|
|
Hemlock, 328 |
sodium, 57 |
|
Hcmpseed calculi. 406 |
Hydrates, composition of, 44, 59 |
|
Heterologoua seriea, 856 |
Uydrio aoetatfl, chloride, nitrate. |
|
Hesyl, 366 |
sulphate, etc., mde the respoc- |
|
Hipporic acid, 270, 898, 401 |
tiye adds— acelie, hjdroohlorio. |
|
Hipa, 338 |
|
|
Hoffner's blue, 384 |
Hydride of antimony, 144 |
|
Homologous eeriee, 356. 373 |
araenicum, 134 |
|
Honey. 839 |
benzoyl. 341, 382 |
|
Bordmm decoHicalum, 331 |
cinnamyl. 882 |
|
Horehound, vide Marrubium |
copper, 283 |
|
Horsemint, 878 |
methyl, 356 |
|
Horseradish oil, 356. 374 |
phosphorua, 283 |
|
Hubbuck's oside of zinc, 100 |
silicon. 292 |
|
Hnmulus lupulus. 881 |
Hydridea, 92, 856 |
|
BydTOrgyri cMoridum corrosivum. |
Hydriodio acid, 225 |
|
158 |
Hydrobromic acid, 223 |
id, Google
|
INDEX. |
||
|
Hydrocarbons. 874 |
Hypochlorites, 241 |
|
|
llvdrocLlorie acid, 26. 219 |
Hypochlorous acid, 24 |
|
|
acid, analytical reactio |
DS of. |
Hypophosphltes, 282 |
|
222 |
Hypophosphorous acid. 282 |
|
|
ftcid, antidote to, 222 |
||
|
acid in organic mixtur |
s, de- |
sodium, 284 |
|
tection of. 887, 389 |
sodium, standard solutio |
|
|
453 |
||
|
445 |
Hyposulphites, 284 |
|
|
Hydrocyanic iteiiJ, 228 acid, analytical rencljo 281, 889 |
ns of. |
|
|
-io, meaning of, 52, 106 |
||
|
acid, antidotes to, 232 |
Iceland mosa, 377 |
|
|
acid from bitter almond and |
Ictksocolla. 3G9 |
|
|
oherrj-laarel, 841 |
■ |
-Ide, meaning of, 52 |
|
acid in organic mistures, de- |
Igasaria, 324 |
|
|
tection of, 889 |
Ignalia, 323 |
|
|
acid in the blood, 282 |
Ignition, 74 |
|
|
acid, volumetric estima |
on of, |
niiciam animtam, 375 |
|
447 |
Illuminating agents, analys |
|
|
Hydroferridoyanio acid, 281 |
496 |
|
|
Hydroferrocyaoio acid, 279 |
Inch, 421 |
|
|
Hydroauoric acid, 281 |
I aei Deration, 74 |
|
|
Hydrogen, 18 |
of filters in qnantitative |
|
|
combustion of, 19 |
lysis, 463 |
|
|
derivntion of word, 27 |
Indelible Ink, 175 |
|
|
explosion of, 19 |
Indestructibility of matter, 3 |
|
|
funotioiiB of, 92 |
Indian liemp, 380 |
|
|
in arlificLal liRht-produc |
ers, 20 |
ink, 385 |
|
ligbtoees of, 21 |
rubber, 382 |
|
|
peroxide of, 76 |
yellow, 383 |
|
|
preparation of, 18 |
Indican, 239 |
|
|
properties of, 19 |
Indiglucin, 239 |
|
|
of. in |
Indigo, 239 |
|
|
organic compoands. |
485 et |
sulphate of, 238 |
|
teq. |
-blae, 2:S9 |
|
|
salts of, 217 |
-white, 239 |
|
|
uaed for bailoonB, 21 |
Indigogen, 239 |
|
|
weight of I litre, 482 |
Indium, 507 |
|
|
weight of 100 cubic inches, 482 |
Infusions, 407 |
|
|
Hydrometers, 427 |
Inhalation of chlorine, 25 |
|
|
Hydrosulphuric acid. 249 |
Conine, 328 |
|
|
Hydros ulpLyl, 249 |
hydrocyanic add, 230 |
|
|
Hydrous compounds, 59, 89 |
Inhalations, 407 |
|
|
Hydrosyl. 249 |
Ink, blaok, 133, 295 |
|
|
Hyoacyamia, 328 |
indelible, ITS |
|
|
Hyo^ami folia, 828 |
Indian, 385 |
|
|
itmm. 828 |
marking, 17o |
|
|
Hyoscyamioe, 828 |
printer's, 3S5 |
|
|
Hyper-, meaning of, no |
sympathetic, 190 |
|
|
Hypo-, meaDirg of, 283 |
Inorganic chemistry, 315 |
|
|
Hypobromitea, 228 |
compounds, 315 |
|
|
Hypochlorite of calcium, 84 |
Introduction, 13 |
|
|
aodiura, 61 |
Inverted sugar, 33S |
id, Google
lodate of potaa
lodat
1,244
lodio acid, Iodide of
ethyl, 354
iron, 26, 110
lead, 170
potassium, SI
sulpbuL', 226 Iodides, 225
analytf "
of mercury, 165, 162 quantitative 474
Iodine, 26, 225 chloride of, 225 dBrivatioii of word, 27 standard solution of, 443
volumetric -water 225
impnrltieB in, 500 lodinitijit, 225 Ipecacuanha, 323 Iridium, 203, 507 IrUfioreBtlna, 378 Irish moss, 333 Iron, 105
acetate of, 113 alum, 103
aniiDoiiio-citrate of, 116 rate of, 118 ctio.is of, 121 .e of, 108, 131, 452 arsenate of, Tolumetiic esti
ination of, 451 black oside of, 119 bromide of, 110 carbouate of, 107, 452 oast, 105
106
deriratioii of word, 28 galvanized, 96 hydrated peroside of, 113 iodate of, 244 iodide of, 26, 110 lactate of, 2S6 magnetic oxide of, 119 magnetic oxide of, estimation
of iron in, 4r' nitrate of, 120
analytic:
in ofEeia! compounds, estima- tion of, 452, 467
ore, magnetic, 105
ore, spathic, 105
ore, specular, 105
oside of, 121
perchloride of. 111
perhydrate, 113
pernitrate of, 120
peroxide of, 114
persulphate of, 112
phosphate of, 109
phosphate of, volumetrio esti- mation of, 452
from, pliosphatps and oxalates, separation of peroxide of, 309
potassio-tartrate of, 118
pyrites, 105
pyrophosphate, 121
qnantitative estimation of, 452, 467
and quinine, citrate of, 117, 320, 490
reduced, 123
aaoeharatad carbonate of, 108, 452
gaecharated carbonate of, to- lunietrie estimation of, 452
-stone, clay, 105
suboarbonate, 108
subsnlpbateaf,112
sulphate of, 106
snlphide of, 109
tersnlphate of, 112
wrought, 105 Isinglass, 369, Isomerism, 334
laomorphiam, the doctrine of, 38 leoniorphoua bodies, 38, 274
Ivory, black, 385
Jalap resin, 344 Jalapa, 344 Jalapm resina, 344
resina, impurities in, 500 Jalapic a<:id, 344 Jalapin, 344 Jalapinol, 344 Jaune brillant, 204 Jervia, 329 Jervine, 329
id .y Google
|
INDEX. 531 |
||
|
Jnices, 407 |
Laws of chemical combination, |
|
|
Jnniper-oil, 376 |
3G |
|
|
Juuiperus, 376 |
Lead, 167 acetate of, 168 |
|
|
Kalium, 27 |
analytical reactions of, 171, 388 antidotes to, 172 carbonate of, 168 chloride of, 171 chroinate of, 173 derivation of word, 28 Iodide of 170 |
|
|
Kuntala, B80 Kermes, mineral, 142 Kiln, 79 Kilogram, 419 Kilolitre, 419 Kilometre, 419 |
||
|
Kinate of qainia, 320 |
nitrate of, 170 oleste of, 170 inorganic mistures, detection of, 387 oxide of, 167 |
|
|
King'8 bine, 384 Kino, 295 KouSBo, 380 KrameriiB radU, 295 |
||
|
plaster, 170 |
||
|
Lao, 367 |
puce-colored or peroxide of, |
|
|
lao-dje, 384 |
170 |
|
|
Laotatea, 285 |
quantitative eatimatiou of, |
|
|
Lac^tic acid, 285 |
438, 471 |
|
|
Laotometer, 368 |
red, 170, 3S4 |
|
|
Lactose, 337 |
snbacetate of, 169 |
|
|
Lactuca, 331 |
sugar of. 168 |
|
|
Laetnoin, 331 |
sulphate of, 173 |
|
|
Lzevogyrate, 338 |
Bulphideof, 167, 171 |
|
|
Lav (.rotation, 338 |
-tree, 173 |
|
|
Lakes, 104 |
volumetric estimatioit of ao- |
|
|
Lampblack, 3S5 |
latiojiflof acetate of, 138 |
|
|
Lamps, gas-, 16, 21 |
white, l(i8 |
|
|
La«a pkilosophUa, 100 |
Leadstone. 105 |
|
|
Lanthaniam, 507 |
Leaf-green, 385 |
|
|
Lard, 371 |
Lecanora, 385 |
|
|
prepared, 371 |
Legumin, 368 |
|
|
Larix evropcsa, 377 |
Lemon-chrome, 172 |
|
|
Latent heat, 60 |
-juice, 288 |
|
|
Laurate of glyceryl, 572 |
-oil, 418 |
|
|
Lanrel-campbor, 378 |
Length unit, 419 |
|
|
Laurio aldehyd, 377 |
Lepidolite, 181 |
|
|
Laatio acid, 373 |
Levulose, 338 |
|
|
LauToeerasi folia, 341 |
Liclien blue, 384 |
|
|
Lavender.oil,376 |
Light carbonate of magnesium, 87 |
|
|
-water, 376 |
earbaretted hydrogen, 356 |
|
|
Lavender, oil of, 378 |
magnesia, 88 |
|
|
Law concerning moleoala |
weight, |
Lignin, 335 |
|
39, 219, 433 |
Lime, caustic, 79 |
|
|
of constant proport |
chloride of, 84 |
|
|
409, 457 |
-kiln, 79 |
|
|
36, IDS, |
-oil, 375 |
|
|
238 |
slaked, 79 |
|
|
reoiprooal proportion |
3,36 |
-water, 80 |
|
solabilitr ot gaaes in |
liquids. |
|
|
60 |
magnesian, 87 |
id, Google
auccat, impurities iii, 51 Llmoiiite, 115 Line, 421 Lini/anna, 372
setiiiaa, 372 Liniment of mercury, 1S4
/e,ricitratu,U6 ferriper<:hleridi,U2 ftrri perrhloridi fortior. 111 ferri perchlorldi foTlioT, impu-
ritiea in, BOl ferri perchloridi fortiar, estl-
Lini.
:, 371
eahis, 371 Linnni, 372 Linseed oil, 372 Liquenrn, 347 Liquldomhar orientale, 383 Liquids, speoifio gravit; of, 425
official, speeifie gravity of, 425 Iitqnor ammonim, QH
' s, impurities in, £ -.elalis, 68
in, 500 CB(imon('i clitoTidi, 140 antimonii cidoridi, impurities
in, 500 anltmonti chloridi, estimation
of antimony in, 4(;9 arssn/co; (8,129 arsenicalis, imparities in, 5 arsenici el hjdrarggn iodidi,
atropite, 326 atropiie siilpAatis, 326 bitmailii et ammo'iitB cilrath^ estimation of bismatli in.
n of ir
3 in,
501
Jerri perniiralis, eatimation of iron in, 467
ferri persalphatis, 112
ferri persulpkatis, impurities in, 501
ferri persalphatis, estimation of iron in, 467
ferri stibanlpkatia, 112
ferri tersulphalis, 112
gutta-percha, 382
hsdrargyri nitratis aeidus, 157
hi/drariigri nitralis acidas, im- parities in, GOI
hydrarggri peTChloridi, 159
iodi, 225
iodinii compoaiiua, 225
litUa effernemenB, 183
HlhiiE effervetcens, impurities in, 501
magaeiia carbonatla, 88
magnesiiE carbonaiis, impuri- ties in, 501
morphiix acetatis, 318
morplii's hydrochtoratis, 318
morphi<E sulphatis, 318
plumbi sabacetalii, 169
pl«m!ii eiibacelatis, impurities
1, 501
1,169
calcii, Impnrilies In, 600
cokie chloratm, 84
caldi chloTttttB, impurities in,
BOO calcis saceharatua, 80 calcie mcekaraius, impurities
in, BOO ckhri, 221 cldori, impurities in, 500
s,49
s, 48
ties in, 501 poiassm, neutraliaiog power
of, 438 potasafE permamjanatia, 53, 185 poiasniE, speeifio gravity of,
427
id .y Google
|
INDEX. i)33 |
|
|
Liquor— |
Magenta, 38S |
|
scda-. arsemalis, 131 |
Magnesia, 89 |
|
sodiE chlorttlfe, 61,454 |
impurities id, 501 |
|
sodiE cMoratte, impurities in, |
calcined, 89 |
|
501 |
fluid, 88 |
|
iodiE cldoHnatce, 61 |
hydrous carbonate of, 89 |
|
sod<e ^ervBscens, 60 |
Magnesia levis, 89 |
|
levis, impurities in, 501 |
|
|
in, 501 |
Magnesi<e carbonas, 88 |
|
strychnim, 3U zinci Moridi, 98 |
carboaas, impurities lu, 501 |
|
carbonas Jeuis, 88 |
|
|
carbonas levis, impurities in. |
|
|
Litliarge, 168 |
501 |
|
LilMiB carboms, 183 |
carbonalis, liquor, 88 |
|
carboaas. impurities in, 501 |
sulphas, 87 |
|
cilr«s, 183 |
salphas, impurities ill, 501 |
|
cilras, impurities in, 501 |
Magneaian limestone, 87 |
|
Lithium, 182 |
Magiiesite, 87 |
|
analytical reactioDS of, 183 |
Maguesiuiu, 87 |
|
carbonata of, 183 |
analytical reactions of, 90 |
|
citratH of, 182 |
ensanthata of, 383 |
|
derivation of word, 29 |
for analytical purposes, 134 |
|
tirflta of, 183 |
|
|
Litmus, 71,384 |
90 |
|
paper, 71 |
and ammonium, pliospIiatB of. |
|
solution of, 71 |
M |
|
tincture of, 71 |
|
|
Litre, relation of, to pints, 420, 423 |
eMoride of, 87 |
|
Liver of sulphur, 45 |
citrate of, 268 |
|
Lixivialion, 62 |
deriyation of word, 38 |
|
detection of, in presence of |
|
|
Lobelia, 328 |
barium and calcium, 93 |
|
Lobelia vinegar, 245 |
pun-ate of, 383 |
|
Lobelina, 328 |
Qnantitative estimation of. |
|
Lobaline, 328 |
465 |
|
Logwood, 25, 428 |
separation from barium and |
|
Long pepper, 329 |
calcium, 93 |
|
Lonking-g! asses, 196 |
salpbate of, 87, 465 |
|
J.oiia hgdrargyri ftova, 162 |
Magnetic iron ore, 105 |
|
hydrargri nigra, 162 |
oxide of iron, 119 |
|
Louiaa-blne, 385 |
Magpie test for mercury, 16S |
|
Lozenges, 407 |
Malachite, 149 |
|
LncLfers, 22 |
Malate of atropine, 326 |
|
Lanar oauslic, 175 |
nicotine 323 |
|
Lupnlin, 381 |
Malates, 3S6 |
|
Zupulus, 331 |
Male fern oil, 373 |
|
Loteolin, 334 |
Malic acid, 386 |
|
Luting, flre-clay, 158 |
Malt, 333 |
|
linaead-meal, 70 |
Manganate of potassium, 53, 186 |
|
Lycopodium, 373 |
Manganeae, 185 |
|
analytical raacliona of, 186 |
|
|
Mace, 377 |
black oiiide of, 185 |
|
Macis, 377 |
derivation of word, 30 |
|
Madder, 384 |
sulpliate of, 188 |
id, Google
133
534 I
Manganeaii oi^dum nigrDiii, 185
Manganous obloride, 186 Manna, 339
im pun Ilea in, SOI M^tnnito, 339
Maiiurnuturing chemists, 14 Manures, analysia of, 49B Maranla, 332 Marble, 78 Marnarine, 371 Marine snap, 372 Markliig-lDk, 175 Marl, 102 Marmalade, 296 Marmor albam, 78 Marsli-gas, 356 Marsh's test of ai Morrubiunt, 331 Maryland senna, 342 Massiuot, 167 Mastio, 380 Masticke, 3 SO Masticbic aoid, 380 Masticin, 380 Malkce folia, 331 Matficaria chamomilhi, 375 MaAer indestructible, 33
May-apple, 328 Meado>T-9weet, oil of, 362 Measurement of tempo ratura, 412 Measures, 417 et seq. Ueohanfcal and chemical oombl nation, driTeretice between, 26,32 Meconate of raorpbiue, 317 Meoonio acid, 387, 392 Medicines, analysis of, 313 Maersvhanm, 391 Mtl, 339
imparities in, 501
boracis, 275
depttralum, 330
so<l(e boralis, 374 Mellases, 339 Hetissic acid, 373 Melting-points, Table of, 415
of fats, &o., to determine, 415
of metals, 416 Melissyl, palrcitate of, 372 Meton-essenoe, 362 Memoranda, analytical, 212, Mentha piperita, 376
viiidis, 376
f, 154 salts, analytical reactions of,
162, 387 sulphate, 157 '.rmrim I'iliB, 140 Mercuraus chloride, 154, 159
f, 154
salt*, analytical reactions of, 1S5
sulphate, 158 Mercury, 153
amido-chloride of, 163
ammontated, 163
ammonio-chloride of, 163
analytical reactieus of, 162
antidotes to, 160
basic sulphate of, 158
black oxide of, 161
cyanide of, 230
chlorides of, 158
derivation of word, 29
iodides of, 155, 16S
nitrates of, 156
nomenclature of salta of, 154
of life, 140
in organic miztares,deteatloii of, 387
oxides of, 160
osysulphate of, 158
quantitative estimation of, 470
subchloride of, 159
sniphatBH of, 157
sulphide of, 163, 164
yellow oside of, 161 Meta, meaning of, 197 Metaboraaic acid, 274 Hetacinnamein, 382 Metagummic acid, 333 Metallic eleraenls, 15 Metalloids, 15 Metals, 15
of minor Pharmaceutical im- portance, 182
457
Table of the fusibility of, 416 Metamerism, 334 Metantimonio acid, 141 Metaphosphates, 287 Metapbosphoric acid, 287 Motastannic acid, 197, 334
of,
id .y Google
|
Metastyrol, 342 |
Morphia, 317 |
|
MalftraiiadalBS, 274 |
acetate of, 317 |
|
Methfluyl, 360 |
analytical reauliona of, 318 |
|
Metliyl, 256 |
302 |
|
hydride of, 350 |
Morphia: acetas, 317 |
|
Eiliioylate nf, 362 |
hydroehUras, 317 |
|
Methylamine, 310 |
hijdrochloras, impurities in |
|
Methylated spirit, 357 |
501 |
|
Metliylane, dichloride of, 360 |
murp-as, 317 |
|
Methylio alcohol detected in pre- |
s'dphas, 317 |
|
sence of ethylio alcohol, 3S7 |
Morphine, 317 |
|
Methylio alcoliol, 357 |
hydroehlorate of. 317 |
|
Metre, relation of, to inches, 420, |
in organic mixtures, detection |
|
422 |
of, 393 |
|
Metrical system of weights and |
quaniitative estimation of |
|
measures, Us relation to the |
490 |
|
English, 422 ei seg. |
Moaaie goW, 198 |
|
Metrical system, weights and mea- |
,l/o«cAM,3Ii8 |
|
sures of, 418 et seq. |
Motion from heat, 60 |
|
Mountaiu-blue, 384 |
|
|
Maieieon, 380 |
limestone. 87 |
|
Mca Po«i^, 337 |
Mucio acid, 340 |
|
Mucilage of Rura acacia, 84 |
|
|
starch, 333 |
|
|
Milk, 367 |
tragaeaiitii, P5 |
|
sugar, 337 |
M<,cilago acaci.^, 84 |
|
amyh. 332 |
|
|
Mimolannio acid, 2I?5 |
tragacanlha. 35 |
|
Mineral chameleon, 187 |
Mulberry-essencs, 36 |
|
kermes, 142 |
-Juice, 384 |
|
purple, 384 |
Mulder's process for estimating al- |
|
rouge, 384 |
cohol, 493 |
|
Minerals, general, analysis of, 306 |
Multiple proportions, law of, 3H |
|
1B8, 338 |
|
|
speoial, analysis of, 496 |
Mnre:^ict, 297 |
|
Minim, 421 |
Musk, 368 |
|
Minium, 168 |
Mustard, 364 |
|
Mirbane, essence of, 363 |
|
|
Mistaraferriaromatica, 123 |
flKcd oil of, 373 |
|
/erri composila, 108 |
Myristate of glyceryl, 372 |
|
. po(o3S(Ed(rolis, 268 |
Myristic acid, 373 |
|
Mixtures, 407 |
Myriaiica, 376 |
|
Hohr's burette, 436 |
Myronate of potassium, 364 |
|
Molasses, 339 |
Myrox^hn Pereirm, 382 |
|
Molecular weight, 39, 319, 432 |
ro;»iA™,382 |
|
Moleoules, 33, 37 |
Myrrh, 381 |
|
Molybdenum, 507 |
Myrrha, 381 |
|
Monads, 91 |
Myrrhic acid, 381 |
|
Monarda, 378 |
|
|
Monobasic acida, 219 |
Narthex assafwtida, 381 |
|
Monobasylous radioals, 219 |
Nascent state, 33 |
|
Monsel's Eolation, 112 |
Nalriam, 28 |
|
Mordants, 104 |
Neat'a-foot 011,373 |
|
Mori sMcu,, 384 |
Necla„dr<^ cortex, 326 |
id, Google
|
636 |
IND |
EX. |
|
HeoUndria 326 |
NltrogBn— |
|
|
NerolLoi1,37e |
properties of, 23 |
|
|
Reatral ebi'omate, 77 |
quantitative estimation of, in |
|
|
Nickel, 190 |
||
|
analytical reactioi |
s of, 191 |
seg. |
|
f, 190 |
relative weight of, 23 |
|
|
oobaltioyanide, 182 |
Nitrohjdfochlorie acid, 146, 236 |
|
|
cyanide, 191 |
Kitromuriatic aeid, 236 |
|
|
derivation of word, 30 |
Nitrous acid, 288 |
|
|
Hfcotia. nicotine, nico |
anhydride, 238 |
|
|
cotylia, 328 |
ether, 353 |
|
|
NMlam album, 100 |
oxide, 238 |
|
|
Niobium, 607 |
Nomenclature of salts :— |
|
|
Kitrate of ammoEiua |
,238 |
alkaloids, 316 |
|
barinra, 75 |
anhydrides, 59 |
|
|
bismuth, 205 |
anhydrous bodies, 59 |
|
|
cadmiam, 204 |
-ate, 49 |
|
|
iron, 120 |
hi, 48 |
|
|
lead, 170 |
carbonization, evaporation, |
|
|
meroary, 156 |
ignition, incineration, 74 |
|
|
potassium, 42, 233 |
double salts, 54 |
|
|
silver, 175 |
hydrates, 43 |
|
|
silver, standard aolution of, |
hydrous bodies, 59 |
|
|
447 |
hyper, 110 |
|
|
sodium, 57, 233 |
-ic, -OU3, 49, 52, 106 |
|
|
strontium, IS4 |
-ide, -lie, 52, 106 |
|
|
Nitrates, 233 |
iron sails, 106 |
|
|
analytical reaotio |
as of, 235, |
mercury compounds, 154 |
|
389 |
per, no |
|
|
quantitative estimation of. |
Non-metallic elements, 15 |
|
|
475 |
Non-melals, 14 |
|
|
Nitre, 233 |
Nordhauseu sulphuric acid, 257 |
|
|
sweet spirit of, 289, 353 |
Notation, 34 el spg. |
|
|
Hitric aeid, 233 |
Notes, analytical, 213, 304 |
|
|
acid, antidotes to, |
239 |
Nutmeg, oil of, 376 |
|
acid in organic m |
xtures, de- |
|
|
tection of, 389 |
Kui vomica, 323 |
|
|
acid, Tolnmetric |
estlmatioD |
|
|
of, 443 |
Occlusion, 202, 203 |
|
|
anhydride, 236 |
Ochre, 383 |
|
|
OBide, preparation |
of, 237 |
Ootohedral, 133 |
|
peroxide, 237 |
CEiiauthylic aeid, 372 |
|
|
Hitrate of ethyl, 353 |
Official liquids, specific gravity of, |
|
|
potassium, 288 |
42S |
|
|
Nitrites, 239 |
substances, volumetric esti- |
|
|
analytical reactior |
3 of, 289 |
mation of, 438, 445, 447, |
|
Nitrobenzol, 363 |
449, 4ri2, 454 |
|
|
Nitroceliulin, 335 |
Oak-bark, 294 |
|
|
Hitrogen, 22 |
black, 383 |
|
|
derivation of word |
27 |
Oatmeal, 332 |
|
in the atmosphere |
22 |
Oil, almond, 374 |
|
osides of, 238 |
amber, 292 |
|
|
peroxide of, 237 |
aniseed, 37B |
|
|
preparation of, 22 |
bergamot, 375 |
id, Google
|
Oil- |
Oil- |
|
bitter almond, 341 |
savin, 377 |
|
bitter almoud, arliflcial, 363 |
spearmint, 377 |
|
buohu, 376 |
sperm, 372 |
|
cacao, 372 |
star-anise, 275 |
|
cajnput, 378 |
theobroma, S72 |
|
camphor, 378 |
|
|
capaionm, 327 |
valerian, 377 |
|
caraway, 37S |
of vilriof, 256 |
|
oardamoins, 376 |
wine, 364 |
|
cascarilla, 376 |
winter-green, 363 |
|
cassia, 376 |
wormseed, 373 |
|
castor, 372 |
|
|
oedra, 376 |
Oils, analysis of, 496 |
|
ehamomile, 375 |
drying, 372 |
|
cinnamon, 376 |
fixed, 372 |
|
citron, 376 |
non-drying, 372 |
|
cloves, 376 |
volatile, 374 |
|
cocoa-nut, 372 |
volatile, process for, 374 |
|
ood-llver, 372 |
|
|
copaiva, 376 |
Olea destiliata, impurities in, 50 |
|
coriander, 376 |
Oleata of glyceryl, 371 |
|
oroton, 372 |
Oleates, 371 |
|
cnbeb, 376 |
Olefiant gas, 364 |
|
dill, 375 |
OIbIc acid. 371 |
|
alder-flower, 377 |
OJeine, 371 |
|
fennel, 376 |
Oleo- resins, 381 |
|
garlic, 364 |
OUoresina capsid, 381 |
|
ginger, 377 |
cabebcB, 381 |
|
hop, 381 |
l«p«lm<e, 381 |
|
liorseuiint, 378 |
piperis, 381 |
|
horseradisl), 356, 375 |
zitigiberU, 381 |
|
juniper, 376 |
Oleum nmygdaicp amarte, 341 |
|
lavender, 376 |
omyqdaU-- dulcis, 372 |
|
lemon, 376 |
a«eihi, 375 |
|
lime, 376 |
anisi, J75 |
|
linseed, 372 |
u'dhiMul,-., 375 |
|
maie-fern, 373 |
beryamu, 375 |
|
meadow-sneut, 362 |
buhuhim, 373 |
|
mnatard, fixed, 37^ |
i-oiupuli, 376 |
|
mnstatd, volatile, 364 |
campkrr.l:, 378 |
|
ueroU, 376 |
curm, J76 |
|
nutmeg, 370 |
cariiofh/lh, 376 |
|
olive, 273 |
cmn.monn, 376 |
|
orange- iiower, 376 |
|
|
orange-rinil, 375 |
tJfiondi 1,376 |
|
orris, 376 |
crotonii, 372 |
|
pepper, 329 |
cubtbie, 376 |
|
peppermint, 376 |
elhereum, 364 |
|
pimento, 376 |
famcuh, 376 |
|
rose, 377 |
gaullhemc 362 |
|
rosemary, 377 |
j«nipe.j, 376 |
|
rue, 377 |
laiendulte. 376 |
|
sassafras, 377 |
Imaats, 375 |
id, Google
Olenm — lini, 372
menlhiE viriuis,
morrhtue, 372
myrisliciB, 376
mj/riiticiE expressiim, 372
a!iv<e, 372
pimentiE, 376
ricini, 372
rosa, 877
rosmariiti, 377
ruttB, 377
labitue, 377
»aesq/Vas, 377
slnopjs, 377
sacdni, 292
euecini i-«c(y?ca(«m, 293
ierebinlhiace, 377
(ieoiTOinfe, 373
t&ymi, 37S
ftpiii, 372
;, 377
OUve-oil, 372 Omimtam, 371 Opal, 291 Opium, 317
viaegCT, 245
impurities in, 602
estimation of morphia in, 490 Orange-chrome, 172 Oranse-flower, 376
-flowBroil, 376
-rind oil, 872
-wine, 347 Orchil, 384 Oroin, 3S5 Ordeal-poison, 328 Oreltin, 384 Orgaaie analysis, 485
bases, 315
ohemlatry, 315
componnds, 315 Orpiment, 383 Orris, oil of, 372 Orthophosphates, 288 Os,8'i
Os uslunt, B2 Osmium, 203, 569 Otto of rose, 377 Oonee, 421
-ous, meaning of, 52, 106 (hi vitellus, 36S Ovum, 3S6
■bile, 371 -gall, 371 Oxalati '
from phosphates and ferrio oside, separation of, 310
quantitative estimation of, 480 Oxalic acid, 261
acid, antidotes to, 362
teotion of, 389 acid, standard solution of, 437 Oxide of aluminium, 102
copper, 150 iron, black, 119 lead, 167 manganese, 185
Oxides of nitrogen, 238 Oxidizing flame, 308 Oxyacid salts, 235 Oxy acids of sniphnr, 384 Osycarbonate of bismuth, 207 Oxjchtoride of antimony, 140 Oxygen, 15
deriration of word, 27
in the air, 15, 23
getable life, 18 preparation of, 15 properties of, 17 QuanlitatiTe estimation ol organic compounds, 481 seq. solubility in water, 17 weight of 100 cubic inol 245 Oxygenated water, 76 Osyhydrates of iron, 115 Oxyiodate of iron 244 Oxymel, 339
of BC[uill, 339 Oxyiiitrates of mercury, 157
id .y Google
Oiynitratea of —
bismuth, 206, 207 Oxy salts, 235
Oxysulphate of mercury, 158 Oxjsulpliicle of antimony, 141 Osoue, 193, 226
Palladium, 203, 507 Palm-oil, 372 Pftlmitftte of cetyl, 372
glyceryl, 373
melisByi, 372 Palmitic aoici, 373 Palmitine, 372 Papaver ri
,ni/er,
■,317
Papaeeris capajiJtB, 317 Paper for Blterlng, 81, 457 Pareirre radix, 337 Paris blue, 385
red, 384 Particles, eiemontary, 33 Pearlash, 42 Pearl-barley, 331 Pearl-white, 206, 385 Pectin, 333 Peiargonio acid, 373 Pellitory toot, 380 Pelosia, 327 Pelosiue, 327
Pentaohioride of antimony, 140 Pentalhionio acid, 284 Pepper, black, 328
cayence, 327
cubeb, 334
long, 384
white, 384 Pepper, oil of, 384
resin of, 384 Peppermint oil, 376 Pepsin, 369 Per-, meaning of, 110 Perbromates, 223 Perchlorate of potassium, 242 Perchloric acid, 243 Peroliloride of iron, 110
platinum, 201 Perfumes, 375 Permanganate of potassium, 5
Peroxide of—
iron, liydrated, 114 nitrogen, 237
PhSG<
18S
Pernitrate of iron.
Peroxide of bariuj
liydrogBn, 76
120
!, 277
iiitical chemists, 14 Pliarmaoeutioal Society ot Great
~ examinations of, 14
Pharmacists, 14 Pharmacy, 14 Pliaraoh's serpent, 393 "• enio acid, 3G3 alcohol, 363 Phenol, 363 Phenyl, 363 Phenylaraiiie, 354 Pboaphate of a
■ ■ ., 78, 82
magnesium and
from oxalates and ferric oxide, eeparatioQ of, 309
sodium, 83 Phosphates, 270
analytical reactions of. 372
qnantitatlve eatiinatiou of, 481. Phosphites, 289
test for, 290 Pliosphoretted hydrogen, 283 Phosphoric acid, 22, 270, 289
acid, quantitative estimation of free, 481
anhydride, 22, 35, 287 Phosphorous acid, 289 Phospboms, 21
CO ml) nation of, 22
derivation of word, 37
detection of, in organic mix- tures, 390
properties of, 22
red or amorphous, 334
tri hydride, 283 Phyllocyanin, 385 Phylloxauthin, 385 Physics, 37
Phgsostigmalisfaba, 328 Pbyaostigma, 328
id .y Google
|
640 INDEX. |
|
|
PhyaoBtigrainB, 328 |
Plumbago, 26 |
|
Piorio aoid, 364 |
Flumbi acetas, US |
|
Figments, 383 |
acelaa, inipnrities in, 503 |
|
Pitla, 407 |
cajboaas, 169 |
|
PUulaoUsetferri.lQ7 |
carbonas, impurities in, 503 |
|
fern carbonatis, 109 |
emptaslrum, 170 |
|
ferri Midi, 27 |
iodidum, 170 |
|
kydrargyri, 163 |
«itras, 170 |
|
hydrargyri sulchloridi compo- |
oxMtim, 1S8 |
|
,ii,^,m |
oiirfuni, impurities in, 502 |
|
phndii e«m opio, 169 |
snbacelatii. liquor, 169 |
|
gvinitt, 320 |
Plnmmer'a pills, 160 |
|
Plhlce anlimonii campositiE, 160 |
Plumbic peroside, 170 |
|
feiri composila, 108 |
Plumbum, 28 |
|
Pimento, 376 |
Pocjila emetica, 139 |
|
oil, 376 |
Podophyili radix, 327 |
|
Pi«ipi«dta anhum, 375 |
resma, 327 |
|
Pinio acid, 379 |
Poisons, antidotes to, fi'i/e Antidotes |
|
Pink saucers, 384 |
detection of, in organic mis- |
|
the common, 346 |
tntes, 387 et seq. |
|
Pins, 196 |
Polybasio acids, 219 |
|
Pint, 421 |
Polybasylous radicals, 219 |
|
Pinui, 377, 381 |
Polyehroite, 383 |
|
Piper nigram, 329 |
Poly gala senega, 346 |
|
Piperia, 329 |
Polygalio aoid, 346 |
|
Piporldia, 329 |
Polymeriam, 334 |
|
Piperidiuo, 329 |
Polymorphism, 334 |
|
Piperine, 329 |
Polymorphous bodies, 334 |
|
Pistachia leTebinthas, 377 |
Polysulphide of calcium, 250 |
|
Pitch, 381 |
Pomegranate root-bark, 296 |
|
burgundy, 380 |
Potash alnm, 106 |
|
Pix burgu«di<:a, 380 |
solution of caustic, 46 |
|
canOtltntis, 381 |
sulphurated, 46 |
|
ligmda, 381 |
vol. eatim. of boI. of, 438 |
|
Plants and animals, oomplemen- |
-water, 48 |
|
tary action on air, 18 |
Potaahea, 42 |
|
Plaster of ammouiacum and mer- |
Potassa, 45 |
|
oary, 153 |
Polassa caustica, 45 |
|
mercury, 154 |
causiica, impurities in, 502 |
|
Paris, 78, 3ti5 |
lulp/turala, 46 ttdphiirata, impurities in, 502 |
|
Plasters, 170, 407 |
|
|
Platiuio salts, 201 |
Polassic acetas, 47 |
|
Piatiuous sails, 201 |
|
|
Platinum, 201 |
bicarbonas, 48 |
|
analytical reactions of, 202 |
bicarbonas, impurities in, 502 |
|
and ammouium, cliloride of, |
biekromas, 193 |
|
71, 462 |
bitarlras, 55, 263 |
|
and potassium, chloride of, 54 |
carbonat, 42 |
|
black, 202 |
carbonof pura, 42 |
|
derivation of word, 30 |
carbonas impnra, 42 |
|
foil, 53, 201 |
carbonas, impurities in, 502 |
|
(Moras, 241 |
|
|
residnea, to recover, 203 |
chloras, impurities in, 502 |
|
spongy, 303 |
cJtras, 49 |
id, Google
Ultras, impurities m, 502 permaaganas, 53, 18S permanganas, impurities 1
iarlras, 50
lartras, inipurities in, 502 .
iarlras acida, 263
larti-aa acida, impurities in, 502 Polassii bromidim, 52
bromidam, impurities in, 50^
ci/aaidam, 229
ferridct/anidum, impurities in, 62
ferrocyanidmn, 229
iodiduiit, 51
iodidam, impurities iii, 502 Potassio-oitrate of iron, 115
-tartrate of antimony, 141, 264
-tartrate of iron, 115 Potassium, 42
acetal« of, 45
acid tartrate of, 54
analytical reactions of, 53
autimoniate of, G3
bicarbonate of, 47, 43S
bicliromate of, 192
bitartrate of, 55
borotartrate of, 375
bromate of, 52
bromide of, 52, 223
carbonate of, 42, 43S
clilorateof, 16, 241
chloride of, 54
chramata of, 76
and platinum, clilDiide of, 54
citrate of, 49
cyanide of, 22
derivation of word, 27
ferridcyanide of, 281
ferroeyanide of, 229, 280
•flame-test, 55
liydrate of, 43
iodate of, 51, 244
iodide ofj 50 46
EX. 541
Potassium —
iiiaiigauate of, 53, 18G
Diyionate of, 3S4
Bitrateof, 42, 49, 233
oleate of, 372
perohlorate of, 242
permanganate of, 53, IBS
preparatiou of, 42
properties of, 42, 44
quantitative estimation of, 436, 457
ted ohromate of, 76, 192
red prussiate of, 281
and sodium, tartrate of, 61
sodium, and ammonium, sepa- ration of, 73
sources of, 43
sulphate of, 49, 236
sulpliides of, 46
sulpliooyanate of, 293
sulpliurated, 48
tartrate of, 50
yellow ohromate of, 76, 192
yellow prussiate of, 22H, 279 Poultices, 407 Pound, 421 Powders, 407
specific gravity of, 428 Precipitant, 64 Precipitate, 54 Precipitated chalk, 80
sulphur, 250 Precipitates, soluble, in solutions of salts, 231
to wash, 80, 81,459, 463
weigh, 457, 459, 461 Precipitation, 54
Preparations of the British Phar- macopceia, chemical, 409
galenical, 407 Prepared cai'bonate of calcium, 62
elialk, 83
lard, 372
Pressure, correction of vol. of gas
tor, 430 Prineipleaof Chemical Philosophy,
33 Printer's ink, 385 Proportions, atomic, 30, 156
constant, 36
multiple, 36
reciprocal, 3(i Proof spirit, 347
id .y Google
|
Propenyl, 364 |
Q,.CTe»s— |
|
Propionic aoid, 373 |
lOicioria, 383 |
|
Propyl, 356 |
Queveniie's iron, 130 |
|
Propylamine, 316 |
Qui»i,E sulphas, 320 |
|
Prout's Jijpotlieaia, 3G |
salphai, impurities in, 502 |
|
Proximate analysis, 4S5 |
val^iartas, 320 |
|
Prune, 339 |
Qninla, or qninine, 330 |
|
Praam,, 339 |
analytical reactions of, 321 |
|
Prussian blue, 280, 385 |
citrate ot iron and, 117 |
|
Prua3iate of potaali, red, 381 |
De Vry's prooess for estima- |
|
of potOBh, yHllow, 229, 280 |
ting, 489 |
|
Prussio acid, 228 |
disnlpLate of, 320 |
|
Pteracarpi ligmim, 384 |
kiuate of, 320 |
|
Plerocarpas lantalinui, 384 |
quantitative eatiuintion of, |
|
Ptyalin, 403 |
. 488 |
|
Pnee-oolored oxide of laad, 169 |
sulphate of, 320 |
|
Palvia algarothi, 140 |
Quinia wine, 320 |
|
angdicui, 140 |
Quinlcia, 323 |
|
antimonialis, 143 |
Qnluiclne, 323 |
|
Quinidia, 323 |
|
|
Puheres effervesceuUs, 63 |
Quinidine, 333 |
|
openenUs, 266 |
Quinqui valence, 39 |
|
Pnrple of Cftssius, 201 |
|
|
foxglove, aotiVB principle iu, |
Raaicala, acidaloos, 44 |
|
342 |
acidulous, formula of, 44 |
|
Pnrrnte oE magneainm, 384 |
alcohol-, 355 |
|
Parree, 3S4 |
basylous, 91 |
|
Putty-powder, 197 |
definition of, 45 |
|
Pyretlirin, 360 |
Raisins, 339 |
|
Psrethri radix, 380 |
Rational formulfe, 348 |
|
Pyrites, copper, 149 |
Reactions, analytical, 43 |
|
iron, 105 |
synthetical, 42 |
|
Pyroaraauiate of sodiom, 131 |
Real alcohol, 348 |
|
Pyroarseniates, 131 |
Realgar, 129 |
|
Pyrogallic acid, 296 |
Reaumur's thermometer, 413 |
|
Pyroligneoaa acid, 345 |
|
|
Fyroluaito, 185 |
Beotiflostlon, 96 |
|
Pyrometers, 415 |
Rectified spirit, 96, 347 |
|
Pyromorpliite, 273 |
Red coloring-matters, 384 |
|
Pyropliosp hates, 290 |
earth, 384 |
|
enamel colors, 384 |
|
|
giavel, 397 |
|
|
Pjrosylio spirit, 357 |
hiematite, 105 |
|
Pgrox^li«, 335 |
lead, 170, 384 |
|
ochre, 384 |
|
|
Quadrivalence, 39 |
oside of iron, 115, 384 |
|
Qnalitatif e analysis, 72 |
phosphorus, 334 |
|
Quautitatire analysis, 409 el seq. |
-poppy petala, 384 |
|
Quautivalence, 39, 91 |
precipitate, IHO |
|
Qnani, 391 |
pruaaiate of potaah, 281 |
|
Quassi'iE Ugnaw, 331 |
-rose petals, 384 |
|
Quassin, 331 |
sandal-wood, 384 |
|
1 Reduced indigo, 239 |
|
|
Quercitron, 383 |
; Reducing flame, 808 |
|
Qwercvs coHfi, 294 |
1 Reiusolj'e test for arseiiicuvii. 133 |
id, Google
|
Eelntive wslglit of Lydrogeu aud |
Roscoo's vanadium, 273 |
|
oxygen, 21 |
Rose-aniline, 386 |
|
Heiinet, 367 |
-oil, 377 |
|
Eeseda luteola, 384 |
Eoaemary-oil, 377 |
|
Kesin, 379 |
Rosin, 379 |
|
of arnica, 380 |
Bottlera tinctona, 380 |
|
of cannabis, 330 |
Rottlerin, 380 |
|
of oapsioiim, 327 |
Rouge, animal. 278, 384 |
|
of oastor, 380 |
mineral, 115, 384 |
|
of ei^t, 380 |
vegetable, 384 |
|
of gnaiacum, 343 |
Riibia thctoTum, 384 |
|
of Indian hemp, 380 |
Robian, 3S4 |
|
of ialap, 345 |
Rabidium, 508 |
|
of kamala, 380 |
Ruby, 102 |
|
of kou99o, 380 |
Eue-oil, 377 |
|
of mastic, 380 |
Rumiein, 277 |
|
Rutate of glyceryl, 372 |
|
|
of pepper, 329 |
Ruthaiiinm, 303, 508 |
|
of podophyllnm, 327 |
Rutio acid, 373 |
|
of pyrethrom, 380 |
alduLyd, 377 |
|
of rottlera, 380 |
|
|
ot "cammony, 349 |
Sahadilla, 339 |
|
Reaaa 371 |
Sabinte oleum, 377 |
|
jalap e 345 |
aaoeharated carbonate of iron, |
|
podopi ,!li, 327 |
108 |
|
Best no d snbstancas, 379 |
carbonate of iron, volametrio |
|
Eb? wis |
estimation of, 452 |
|
Re p rito y materials of food, 3fi8 |
Saccharic acid, 340 |
|
Retort 95 |
|
|
RiiBados pelala, 464 |
Saccharine substances, 331 |
|
ma n suectis, 342, 385 |
Saceharometer, 493 |
|
Man catl<ayt!c»s, 3S5 |
Sacchamm laclis, 337 |
|
fee 0 iui, 383 |
purijicatiwi, 337 |
|
Rhapont c n, 277 |
nsluin, 339 |
|
Ehatany root, 295 |
Safety.lamp, 21 |
|
She ad r 277 |
SafBower, 384 |
|
Saffrflnin, 383 |
|
|
Rheio aeia, 377 |
|
|
Rheiti, 277 |
bastard, 384 |
|
Bheomiii, 277 |
Safren, 377 |
|
Ehodiiim,205 |
Sago, 332 |
|
Kliubai-b, oxalate of caloiam front, |
Saliein, 345 |
|
400 |
Salicyl, hydride of, 345, 362 |
|
Bhubarbio acid, 277 |
Salicylate of methyl, 362 |
|
Bhnbartjariu, 277 |
Salioylona acid, 3li2 |
|
Ekaa eotinas, 383 |
Saligenin,345 |
|
Rieinoieate of glyceryl, 372 |
Saliva, 403 |
|
Sal praaella, 334 |
|
|
Roocella, 384 |
Salt, commnn, 5G |
|
Roohellesalt, 61, 265 |
defliiitionof a, 42 |
|
Bock-salt, 66 |
of sorrel, 2lil |
|
Boll snlplinr, 240 |
Saltpetre, 233 |
|
Soate eaninmfructus, 338 |
Salts, action of the blowpipe on. |
|
cenlifbUie petala, 377 |
308 |
id, Google
|
Salts— |
Scanmonife radix, S4G |
|
|
notion of sulphur! |
acid on, |
resina, 34G |
|
307 |
resina, impoiities in, 502 |
|
|
of ammonium, volatility of, 72 |
Scammonin, 346 |
|
|
analogies of, 62 |
Scammoniol, 346 |
|
|
aiialjsis of insoluble. 305 |
Scam»icmum, 346 |
|
|
constitution of, 44 |
91, 217, |
Scammoiiy, resin of, 346 |
|
234,247 |
Scents, 375 |
|
|
formation of, 47 |
Scbeele's green, 136 |
|
|
Schist, 102 |
||
|
phyaioal properties |
of, SOB |
Schweinfartli green, 136 |
|
aubstitntiou of, for eacli other. |
Seienoe of chemistry, 14 |
|
|
e3 |
Scilla, 339 |
|
|
table of the solubility or in- |
ScopaHicac,imiaa,Z2^ |
|
|
solubility of, in w |
ater, 302 |
Scoparin, 329 |
|
Sal VBlalile, 67 |
Sea-salt, 60 |
|
|
S„mb»ciJ,>res, 377 |
Sediments, urinary, 397 |
|
|
Sana, 291 |
urinary, microscopic exami |
|
|
-bath, 24 ■ |
nations of, 308 |
|
|
-tray, 24, 169 |
Seidlitz-powder, 2G5 |
|
|
Sandstone, 291 |
Seleninm; 508 |
|
|
Sanguinariua, 329 |
Senegte radix, 346 |
|
|
Tinegav, 245 |
Senna alexandriaa, 341 |
|
|
Santalin, 384 |
indUa, 341 |
|
|
Sepia, 385 |
||
|
Santonin, 345 |
Serolin, 367 |
|
|
Santon,n,m, 345 |
Serpenlarioi radix, 331 |
|
|
impnritiea in, 502 |
Secnia prn-parttlam, 372 |
|
|
Bantoiiiretin, 3-ia |
Sexi vale MOB, 39 |
|
|
Sapsu-wood, 3g4 |
Shale, 102 |
|
|
Sap-green, 384 |
Sherry wine, 347 |
|
|
Sapo duius, 370 |
Sienna, SS5 |
|
|
(ju> us, Impurities in |
503 |
Silica, 232 |
|
mollis, 370 |
Silicate of altiniinnm, 103 |
|
|
mollis, imparities in |
602 |
calcium, 7S, 291 |
|
Saponin, 346 |
Silicates, 291 |
|
|
Sapphire, 102 |
qiiautitative estimation of |
|
|
Sareolaotio acid, 286 |
4S4 |
|
|
Sarsaparilla, 346 |
||
|
5aiJ<t>arf/a:, 346 |
ailioii! acid, 291 |
|
|
Sassafras-oil, 377 |
Siliciurelted hydrogen, 292 |
|
|
SassB/ias radii, 377 |
Silicon, chloride of, 292 |
|
|
Sassafrol, 377 |
derivation of word, 20 |
|
|
Bat mated solutions, boil |
Dg -points |
fluoride of, 292 |
|
of, 414 |
hydride of, 292 |
|
|
Saturating power of o |
trie Hcid, |
oside of, 292 |
|
203, 505 |
Silver, 173 |
|
|
power of tartaric |
eld, 265, |
araraouio-nitrate of, 137, 164 |
|
505 |
analytical reactions of, 176 |
|
|
Saturation, 46 |
antidotes to nitrate of, 176 |
|
|
tables, 2S5, 2C9, 50 |
arseniate of, 137 |
|
|
Saturn, IBS |
arsenite of, 137 |
|
|
Savin-oil, 377 |
chloride of, 174 |
|
|
Saxon bine, 384 |
coinage, 174,438 |
|
|
Sasony blue, 384 |
ryanide of, 176 |
id, Google
|
INUEX. |
545 |
|
|
Silver- |
Sodas— |
|
|
by uupellntion, estimation of, |
pkospJias, S3 |
|
|
473 |
p/iosp/ias. impuriliea i |
,508 |
|
devivatLon of xtoril, 29 |
su/plms. 221 |
|
|
sulphas, impurities in |
503 |
|
|
nitrate of. 171, 175 |
iulphis 253 |
|
|
oiido of, !76 |
vaUrianas, 298 |
|
|
qunnlitative estimation of, 472 |
n, 508 |
|
|
standard solution of nitrate of, |
Soda ehloridum, 56 |
|
|
447 |
Sodium, 56 |
|
|
sulphide of, 173 |
acetate of, 58 |
|
|
tree, 176 |
acid carbonate of, 59, |
488 |
|
Stuapis, 361 |
analytical reactions of, 68 |
|
|
impurities in, 503 |
antimoniateof, 63 |
|
|
Siplion, vide Bjpiioii, |
araeniate of, 131 |
|
|
Si^e, 869 |
arsenite of, 129 |
|
|
Slnied lime, 79 |
bicarbonate of, 58 |
|
|
Blate, 102 |
bromate of. 62 |
|
|
Sniftlt, 189, 384 |
bromide, 62 |
|
|
Smilooiu, 846 |
carbonate of, 67, 62. |
258, 188 |
|
Soap, ammonium, calcium, liaid, |
carbonate of, manufacture of. |
|
|
potassium, sodium, Suft, ^71 |
(i2, 253 |
|
|
Soap-Btone, 385 |
cblorate of, 62 |
|
|
-wort, 346 |
diloride of, 56 |
|
|
"Soda," 259, 411 |
citnite of, 62 |
|
|
Soda-alum, 102 |
derivation of word, 28 |
|
|
-aeli, 62, 441 |
||
|
caastio, 57 |
byOrate of, 57 |
|
|
Soda causUca, 67 |
hypocliloriteof. 61 |
|
|
causliea, impurities in, 503 |
||
|
tartarata, 01 |
iodate of, 62 |
|
|
taHarBta, impurities in, 603 |
iodide of, 62 |
|
|
Soda powders, 62 |
manganate of, 62 |
|
|
eolation of chlorinated. 61, 456 |
nitiate of, 56, 288 |
|
|
atandard solution of, 144 |
||
|
yalerianate of, 298 |
phosphate of, 83 |
|
|
volumetric estimation of, 438 |
potas'inra and ammon |
lum, se- |
|
■wntei-, 60 |
paration of, 73 |
|
|
5orf<e atetas, 68 |
quantitative estimatiar |
of, 138, |
|
aeetas, impurities in, 503 |
161 |
|
|
nrwnws, 131 |
||
|
sulphate of, 221 |
||
|
bicarbonaa, 50 |
sulphite of, 283 |
|
|
bicarbonas, impurities in, 503 |
Talenannteof, 298 |
|
|
ioras, 274 |
Soils ftiialjsis of, 496 |
|
|
caTbanas, 259 |
Solanii 329 |
|
|
carhonas, impurities in, 503 |
Solamne, o29 |
|
|
earbonai exsiccata, 69 |
Solanum didcumara, 329 |
|
|
chlorata, liquor, 61,155 |
Solder, 167, 196 |
|
|
dtro-tartraa effervescms, 62 |
Solids lighter than water, |
to tnke |
|
hyposulpkU, impurities in, 503 |
tlie specific gratify |
f, 429 |
|
liquor, 57 |
to take the specific gi |
Bvilj of, |
id, Google
Solubility of carbonic aciJ gas in
of gfises in liquids, 60
of preoipitntes in strong soln-
tions of salts, 231 or insolubility of salts in water, Table of, 802 Soluble oream of tartar, 275 glass, 291 Bubstances, to take the specific
gravity of, 429 tarUr, 291 SolTttton of acetate of
fteetate of potassium, 4.G acetate of sodium, 53 albumen, 309 ommonia, GG ammonio-nitrote of silTer, 137,
1G4 ammonio-salpbate of copper,
137, 164 ammonio-salphate of magne'
slum, 4S1 arsenic in acid, 129 arsenic in alkali, 129 boracic ocid, 271 bromine, 224
carbonate of amDioniiim, 07 chloride of ammonium, 05 cbloride of antimony, 189 obloride of barium, 75 chloride of calcium, 78 chloride of calcium, saturated,
78 ■ chloride of gold, 20O chloride of tin, 196 ohloride of zinc, 98 chlorinatea lime, 84 chlorinated soda, 61, 464 chlorine, 24, 221
Solntion of—
peruilrate of iron, 120 persulphate of iron, 112 phosphate of sodium, 88 phosphoric acid, 271 potash, 43, 45 red prussiate of potash, 281 soda, 57 strychnia, 824 autiaoetate of lead, 109 biilplmte of cakium, 85
eof
67
ferridoyanideof pi
ferrooyanide of potassium, 281
gelatine, 869
iodate of potassium, 51, 214
iodide of potassium, 51
iodine, 225
lime, 81
litmas, 71
nitrate of mercury, 157
oxalate of ammonium, 63
pei-ohloride of iron. 111, 112
perohloride of mercury, 159
percbloride of platinum, 201
sulphate of ii ,
fculphydrate of a
tartaric acid, 204
yellow prussiate of potash, 280 ^.lOt, 20 Source of heat, IG
reign, weiglil of the, 109
beavy, 75
irc, 105
ne, 329
Spathic
Spearmtni ou, iiH Specific gravity, 424
gravity of gases, 480
gravity of liquids, 425
gravity of official liquids, 425
gravity of ojcygon, 21
gravity of powders, 428
gravity of solids, 428
gravity of solids lighter than water, 429
gravity of soluble substances, 429
weight, 424 Spectrum analysis, 313 Speoular iron-ore, 105 Speculum metal, 196 Speiss, 190 Spermaceti, 872, 415 Spenn-oii, 372 Spirea ubnaria, 345 Spirit of French wine, 350
methylated, 857
of nitrous ether, 289, 853
of nitrous etber, adulterated, 358
proof, 347
id .y Google
ftunlyais of, 493 Spirilui atkerh, S58
alheria nilrosi, 353
ixtheria nitroii, impurities i
603
,67
aromaliaia, impudties
StearoptenH, 37i Steatite, 885 Steel, 105
wine, lis
.nm, 28
Still. !<5
Stoddirt'a test for quinine, 321
Stone- eonl, 105
!, 375
cklorofurmi, impurities io, 503 frumenti, 847 juiiiperi, 3T5 lavandii/iB, 875
!, 375
Uauior, 847
feHiiior, impiirities in, 608
jiniffiHici, 850 Spodumene, 183 Spongy platinum, 203 SpiULefii, 280 Spurge lanrel, 280 Squill, 339 Standard Rold, 199 Standard soluUon of liypoBul- plute of sodium, 453
solution of iodine, 448
GoluCionofnitrnte of silver, 44
Bolution of oxalio aoid, 487
solution of red cbromate poUiesium, 451
solution of Eoda, 444
solution of Eulpliunc ncid, 4J Staanate of sodium, 197 Stannic acid, 197
anhydride, 197
chloride, 197
oxide, li)7 Stannous chloride, 196 SiaiiJium, 80 Star-anise oil, 375 Starch, blue, 331
qnontitative estimation of, 492
tm 1&5
e IH4
Sire
Strontium 184
amljti il reactions of, 18i
cnibonnte of, 184
lenvalion of word, 29
nitrate of 184
sulphate of, 184 Structure of fiame, 20 Strgchn a 828 '*;rjcAiii<e sulphas, 323 Stryohnift or strychnine, 828
jtrychiiine, impurities id.
Styrax bmioin, 382
prreparatus, 382 Styrol, 882
67, 158 [■,249
S 40
d 292 Sucdnum, 292 Suecui limonum, 2G8 Sucrose, 887 Suet, 872
prepared, 872
hismuth, £ d il J deoiidiied, quan- estimation of, 458 idized, quantitatLve I on of, 448 products, 300
id .y Google
brown, 887 ■candy, 337
stimation of, 491
BnlpMde of s.
aollmony, 1S9, 141 ■ I, 129, 135
I, Hi
. 161
nc, 90, 100 „„.j.„.iie8, quftntitativ
of, 477 SulphiileE, 249 Sulphindigotio acid, 2Z Solphindjlic aoid, 238 SulpMtes, 262 aiialjlical n.
' quaatitadve ^< ....<-..
SulphocyanniB of alljl, 864 buljl, 356 iron, 123
Sulphocyanatea, 203 SulpUooyanio acid, 293 Sulphoeyanides, 293 Sulphocyanogen, 298 Snlphnvinic aoid, 352 Sulphtll, 26
aduUerntion of. 251
allolropy of, 335
onalyFicn.! reactions of, 251
n of word, 27
jtlmnllon of, 4
flowers of, 249
iodide of, 226
osy acids, 884
preoipilated, 251
roll, 24
sublimed, 249 Sulphur latum, 249
prcedpUatum, 251
pracipUalam, impurities in, 503
it^limatum, 249
tuUimabtm, impurities In, 508 Sulpliiirated potash, 46 Sulpliurets, vide Sulphides Sulphuretted hydrogen, 69, 249 Sulphuric acid, 254
acid, antidotes to, 257
aoid, aromatic, 253
acid, dilute, 256
acid, fuming, 256
aoid, Nordhausen, 256
acid in organic miitares, de-
444 anhydride, 258 Salphuris iodidum. 226 iodiilum, iropurilie Sulphurous Ncid, 26. 2 aoid. Yolumeti' 449
Sulphydrio acid, 249 Sjmbul, 381
Superphosphate of lime, 271 Supporters of combustion, 20 Supposiioria acidi tantiici, 294
morpAite, 8 1 8
plumbi composiia, 169 Siippoajtoi'ios, 407 Surface uult, 419
id .y Google
|
INDEX. |
|
|
Bwect spirit of nitre, 280, 353 |
Terra i!i slonna, 384 |
|
epirit of nitre, adulterated, 8G8 |
|
|
Sylvie (teid, 379 |
Tesla prmpiiTaia, 82 |
|
SjinboiB of elements. 27, 84 |
Test-papers, 71 |
|
illustration of cliemical action |
-tube. 10 |
|
by, 84 |
Tetrathionic acid, 281 |
|
Sjmpatlietic inks, 190 |
Tetrjl, 856 |
|
Synaptase, 341 |
Thallium, 508 |
|
Syntbesis, 42 |
Theia, 329 |
|
Syphon, 81 |
Tbeine, 826 |
|
Syrup of iodide of Iron, 26 |
Thenard'B blue, 884 |
|
Syrupfl, 407 |
Theobroma oil, 372 |
|
Syrupi, impurities in, 503 |
Tlieriaca, 839 |
|
SgrHpua auraniii, 370 |
Thermometers, 413 |
|
auraniii fioris, 876 |
Celsius's, 413 |
|
fern iodidi. 2@ |
Centigrade, 413 |
|
fei-H pliosphatis, 109 |
I-'iihrenheit's, 413 |
|
fuscai, 339 |
Renumor's, 413 |
|
Thcrmometnc scales, oonve |
|
|
Tabasi folia, 328 |
degrees of, 413 , |
|
Tamarmdut 2IJ7 |
Thionic acids, 284 |
|
impurities in, 508 |
Thorinum, 508 |
|
Tannic acid, 293 |
Thorium, 508 |
|
Tanning, 2B4 |
Thorn-apple, 320 |
|
truutaiuDi eos |
Thus amerkamm, 381 |
|
Tapioca, 382 |
Thyme, oil of, 378 |
|
TaraxMi radix, 881 |
Thymene, 378 |
|
Taraiacin, 831 |
Thymol, 878 |
|
Tartar, oream of, 42, 55, 203, 188 |
Tin, 195 |
|
emetic, 141, 2G4 |
analytical reaclinna of. |
|
emetic, estimation of ontimony |
antidotes to, 199 |
|
in, 468 |
block, 195 |
|
Tartarated antimony, 141 |
chloride of, 196 |
|
Tartano aojJ, 2li8, 203 |
derivaliou of word. 30 |
|
saturating power of, 445 |
dropped or grain, 196 |
|
Tartar meining of, 2G3 |
foil, 196 |
|
Tartarus boraxatas, 270 |
granulated, 190 |
|
osideof, 195 |
|
|
antimony and polassiuiH, 141, |
plate, 196 |
|
204 |
prepare- litiu or, 197 |
|
potassium, acid, 42, 55 |
-stone, 105 |
|
tacks, 196 |
|
|
potassium and Bodium, 61 |
-while cobalt, 389 |
|
Bodium, 55 |
Tinctvra fa-ri accmis, 113 |
|
Tartrates, 50 |
ferri perchlcridi, 112 |
|
analytical reactions of, 266 |
iodi, 225 |
|
Yolumetrio estimation of, 41 |
iodimi, 225 |
|
Taurine, 371 |
composita, 225- |
|
Taurooholates, 37 |
qumiie. 820 |
|
Tellurium 508 |
mctuYe^, 112 |
|
Temperature correction of Tol. of |
Tinctures, 112, 407 |
|
gas for, 430 |
TinneTelly senna, 841 |
|
measurement of, 412 |
Titanium, 508 |
|
Terebmtliina, 877 |
Tobacco, 328 |
|
cmademk, 381 ■ |
Tolu, balsam of, 882 |
id, Google
550 IN
TOtK lea moia, SS2
Toiioology, B86
Tra glean ih, 85
TragacftDtbn, S5
Treacle, S39
Triads, 1*2
Triangle, wire, 72
Tribieic adds, 219
Trjb(i8jlouB radicnlf, 219
Trietbjlamine, 316
Ttietbjlift, 316
Trinitroceilulin, S35
Triphane, 183
Trilhionic acid, 284
Tritjl, 850
Tritjlift, 318
TriTaience, 39
Trivalent radicals, 39, 4G, 01
Trochisd acidi tannici, 294
bismulki, 206
ferri redacH, 120
morphm, 318
moTpkiie el ipeeacuantia, 318
potaasce c/iloralig, 242
tod/e bicarbonalia, 60 Tabe-futinels, 69 Tabes for collecting gases, 16
glass, vide Glass Tubes Tungsten, 508 TurgitB, 115
,275
Turmeric paper Turnbull's blue, Turnsole, 384 Turpentine, 877
Ameiicim, 3 77
Bordeaux, 377
Canadian, 877
Chiao, 377
French, 877
Venice, 377 Turpetli mineral 158
Tjpe-nietol, 139, 137
Ulmi cortex, 295 Ulmuifaiva. 295 Ultimate analysts, 485 Ultramnnne blue, 385
green, 3S5 Umber, 386 Ungueniam aconitiie. 325
ar«;i, 141
cadmiiodidi, 204
hgdrargyn, 154
hydTorgyri ammonmti, 164
hydrargyri iodidi rahri, 168
hgdTttrgyri nitratii, 157
kydrargyri oxidi rubri, 161
hydrargyri subckloriiS, 160
iodi, 225
plumbi ocetatit, 169
plumbi caTbonatis, 168
plumln iodldi, 170
pl-umli luhaeetatis eomposilum. 169
tulpliurU iodldi, 226
xinci, 99 Units of capacity, 419
surface, 419
weiglt, 419 Uni valence 89
Univalent radicals, 39, 44, 91 Uranium, 508 Urate of lithium, 183 Urates, 297 Urea, 278, 395
arliBoijil, 278, 896 Uric acid, 296, 399 Urinary calculi, 404
calculi, examination of, 404
deposits or sedinients, platei of, vide 899 et seq.
Eedioients, 397
sediments, microscopical ei-
Urine, 394
diabetic, 886, 895, 492 Urinometei', 427
Valerian oil, 377 VaUrianm radix, 877 Valerianate of quinia, 277
sodium, 238
sine, 100, 298 Valerianates, 297 Valerianic acid, 297, 878 Valerol, 877 Vanadates, 274 Vanadinite, 274 Vanadium, 273, 603 Vanilla, 382 Vapor acidi hydroeyanici, 230
id .y Google
iodi. 225 Vfipor-denaity, 431 Variolaria, 385 Vegetftble albumen, SOS
and unimnl life, rcintion of, '.
jelly, 383 rouge, 384
Bnbstancea, 315 et seq. Venetian red, 115 Venice tarpentioo, 377 Veratn vitidis radix, 829 Veratria, 829
impurities in, 503 Verntria or Veratrlne, 32!) Veratmm album, 329 Verdigris, 150 Vermilion, 165 Vinegar, 2i5
of c intharides, 245
equill, 246 Vinum anlimom'oh, HI
auran/ii, 347 i, 118
ferri cilratis. 118
VitHol, blue, 107
green, 107
oil of, 256
white, 107 Volatile oils, vide Oils Volatility of salts of ammonium,
72 Volatilization, 72 Volcanic ammoDia. 65 Volume, combination bj, 35
of gas, corrections of, 480 Voliunettio analysis, 410, 436 Q of acetate of lead,
440
of acetic acid, 445 ofaoMs, 443 of alkalies, 43G
of alkaline cai'bo-
of nrseniate of
al solutions, 449
a of chlorinated soda,
n of hycli'oclilorio 445 nuf hydrocyanic acid,
n of hyposulphite of
,440
n of iodides, 447
n of magnetic oxide
452 n of nitric acid, 445 n of ofScial com- , 438, 445, 447, 44i»,
m D of engar, 402 es m n of sulphides, 477 m n of sulphites. 478 ro Q of sulphuric acid, 4 6
El n of sulphurous acid, 449 estimation of tartrates, 441 eolutions, 437, 442, 444, 147, 448, 451,453 Vulcanite, 382 Vulcanized India-rubber, 382
WasbJiig-boltles, 81, 458 precipitates, 81, 458 Water, 96
id .y Google
|
Water—- |
Wo |
od— |
|
|
distilled, 9S |
oil, 381 |
||
|
-balli, 460 |
spirit, 357 |
||
|
boiliug-poiatof, 414 |
lar, 881 |
||
|
-oveB, 458 |
Womseed, 378 |
||
|
of orystallizition, 59, 60 |
Wrought iron, 106 |
||
|
ees- |
|||
|
tiination of, 434 |
Yard, 421 |
||
|
cubio iQoliea of, in a gallon, |
Yeast. 347 |
||
|
430 |
Yelkof egg, 306 |
||
|
eTBporstioo of, 47 |
Yellow coloring-mattes, 383 |
||
|
formation of, es pressed |
lij |
ochre, 388 |
|
|
eyrabols. 34 |
sienna, 383 |
||
|
weight of 1 cobio inoli of |
431 |
wax, 871, 414 |
|
|
weiglit of minim, drachm. |
wood. 383 |
||
|
ouDce, pint, and gallon |
421 |
Yoll! of egg, 366 |
|
|
mi, 371 |
Yt |
rinm, 508 |
|
|
WeigUlng-tubea, 458 |
|||
|
Weiglit, 417 |
Zfiffre, 189 |
||
|
of air, 431, 432 |
Zinc. dC. |
||
|
of hydrogen, 431, 432 |
ncctiite of, 99 |
||
|
of water, 431 |
anaiytical reactions of, 100 |
||
|
specific, 424 |
antidotes to, 101 |
||
|
Weights, atomic. 87 |
carbonate of, 96, 98 |
||
|
balance, 418 |
ciiloride of, 97 |
||
|
and measares of the ra |
trio |
derivation of word, 28 |
|
|
decimal system, 418 ;( |
fj. |
-ethyl, 855 |
|
|
and measures of Ihe Br |
liah |
granulated, 19 |
|
|
Pharmneopceia of 18C7 |
12i |
||
|
Weld, 384 |
of, 389 |
||
|
Wheaten flour. 881 |
oside of, 99 |
||
|
Whey. 337, 867 |
quantitative estimation of, 466 |
||
|
Whistej, 347 |
sulphate of, 97 |
||
|
White arsenic. 123 |
sulphide of, 9S, 100 |
||
|
indigo, 239 |
TBlerianate of, 100, 298 |
||
|
lead, 168 |
white, 99 |
||
|
pepper, 829 |
Zi |
ei aMlai, 99 |
|
|
pigments, 38G |
acdm, impurities in, 504 |
||
|
preeipitntB, 164 |
|||
|
vitilol, 107 |
carbonae, impurities in, 504 |
||
|
was, 372, 4114 |
ckloridi, liquor, 98 |
||
|
Whiting, 82 |
cUoridum, 97 |
||
|
Wine, 347, 493 |
|||
|
antimonial, 141 |
|||
|
iron, 118 |
oiidura, impurities in, 504 |
||
|
orange, 847 |
eulphaa, 97 |
||
|
quinine, 820 |
sulpliiis, impurities in, 604 |
||
|
Bheri'y, 347 |
viiffuenlum, 99 |
||
|
eteel, 118 |
vaMnna,, 100, 298 |
||
|
Wint«r-green, oil of, 862 |
vuleriiinns, impurities in, 504 |
||
|
Wire-gauze tray, 24 |
Zi |
am, 96 |
|
|
triangle, 73 |
gramihitum, IS |
||
|
Witherite, 76 |
Zt |
||
|
Wood-charcoal, 83 |
Zi |
couium, 508 |
id, Google
CATALOGUE OF BOOKS
i3:E::isri=L-5r o. i_,e:^^.
The books in tLe ontiEied list will ba sent by mail, poat-iiaid, to any PaetOIEca in the United States, on receipt of the printed priees. No
tlemen vrill dierefure, in most eases, find il more convenient to deal irith
Detailed catalogues furnished or sent free lij mail on upplication. An illus6rftted catalogue of 64 octavo pages, handsomely printed, mailed on receipt of ID cent3. Address,
HENRY 0, LEA, Nos. 705 nnd 70S Sanaom Street, Philadelphia.
A MEHICAN JOURNAL OF THE MEDICAL SCIENCES, 1 ■a- Quarterly, I ,. .
MEDICAL NEWS AND LIBKAST, monthly, | ,, ,,
BAKKING'S HALF-YEARLY ABSTRACT OF THE!-^"""* ''*' MEDICAL SCIENCES. 2 vols, a year, of abuut -.m i^^j ," „(,
■t^ annum, $2 5(
ALLEN (J.M.) THE PRACTICAL ANATOMIST i or. The Stuoest'b Guide in the DisSEOTiNa Room. With 268 ij lustrations. 1 vol royal IZmo., over 600 p.iges, cloth, $3. A SHTON (T. J.) ON THE DISEASES, INJURIES, AND MALFOR- ■i^ MATIOSS OP THE RECTUM AND ANUS. With remarks on Habitual Constipation. Second American from the fourth London edition, with illuattations. 1 vol. 8vo. of about 360 pp., cloth, $3 2i.
ABNOTT (HEIL) , ELEMENTS OE PHYSICS ; or. Natural Philo- BOPHY, GENEEiL AMD MEDICAL. 1 vol. 8vo., With it lustrations, cloth, $2 2a.
ASHWELLOAMWEI), A PRACTICAL TBBATISE ON THR DIS- EASES OF WOMEN. Third American from the third London edi- tion. InoneSvo. vol, of 528 pages, cloth, $3 50. ASHHURST (JOHN Jr.) THE PRINCIPLES AND PRACTICE OP SURGERY FOR THE USE OF STUDENTS AND PRACTI- TIONERS. {Pffpariiig.) ATTFIEID'S CHEMISTRY— GENERAL, MEDICAL, AND THERA- PEUTICAL. In I vol, 12mo. (Nearlt, ready.) BBINTON [WILLIAM), LECTURES ON THE DISEASES OF THE STOMACH i with an introduction on its Anatomy and Physiology. From the second London edition, with illustration!. I vol. Svo. of about 300 pages, cloth, $3 25.
id .y Google
2 liENRY C. LEA'S PIJBLICATIOKS.
BBANDE (WM. T.), AND AUSED B. TATLOH. CHEMI8IBY. Second Ametioan edition, thoroughly reviBed bj Dr. Taylor. In one large iind hondsomo octavo volump, extra oloth, 35; leather, 46.
BIGELOW (HEHBY J.) ON DI8L0CATIOH AND FRACTUEG OF TUB HIP, with the Reduction of the Dialoentinns by the Fleiion Mc thod. In owe 8vo. toI. of 150 pp., with illuatrationa, est. cloth, $2 bli.
BABHAM (W. R.) RENAL DISEASES r A CLINICAL GUIDE TO THEIR DIAGNOSIS AND TREATMENT. With Illustratione. 1 vol. 12mo., estra cloth, $2 00. iJusl iistied.)
BUMBTEAD (F. J.) THE PATHOLOGY AND TREATMENT OP VENEREAL DISEASES. Including the results of recent investi-
the aubieo Sio., of fii
B'
610 page?, cloth, tb.
■AHD CULLEEIER'S ATLAS OP VENEREAL, See 'Cullebier.'
lABCLAT (A. W,) A MANUAL OF MEDICAL DIAGKOSIS ; being
' in Analysis of the Signs and Symptoms of Disense. Third American
from the second revised London editioD. I toI. 8vo., of Hi pages,
cloth, fts ao,
BAELOW (OEOSGE H.) A MANUAL OF THE PRACTICE OF MEDICINE- With additions by D. F. Condie, M.D. 1 vol. 8yo., o( over 600 pnges, oloth, $2 50.
BAIBD [ROBERT), IMPRESSIONS AND EXPERIENCES OF THE WEST INDIES AND UNITED STATES. 1 vol. royal 12mo., oloth,
BUCKLER (THOMAS H.) ON F I BRO- BRONCHITIS AND RHEU- MATIC PNEUMONIA. 1 vol. 8ro., of 150 pnges, oloth, gl 25. BARNES (ROBERT.) A PRACTICAL TREATISE ON THE DIS- EASES OK WOMEN, In one handsome Svo. vol. {Fr^arivf;.) BRYANT (THOMAS.) THE PRACTICE OP SURGERY. In one handsome volume, with many illustrations. I^Prspanitg .) BLAHDFOBD (U, FIELDIHO.) INSANITY AND ITS TREATMENT. In one handsome 8vo- vol. {Just ready.) BOWMAN (JOHN E.) A PRACTICAL HAND-BOOK OF MEDICAL CHEMISTRY. Edited by C. L. Bloxom. Fifth American, from the fourth and revised London edition. Witb numerous illustra- tions. 1 vol, royal 12mo. of 350 pages, cloth, £2 25.
INTRODUCTIOS TO PRACTICAL CHEMISTRY, INCLUDING
ANALYSIS. EdiWd by C. L. Blosara. Fifth American, from the &fth and revised London edition, with numerous illustrations. 1 yol, royal 12mo. of 3S0 pages, cloth, $2 25,
BBODIE (SIRBEMJAKIH). CLINICAL LECTURES ON SURGERY. 1 voL 8vo., of 350 pages, ololh, $1 26. CHAMBERS (T. K,} THE INDIGESTIONS ; OR, DISEASES OF THE DIQESTIVB ORGANS FUNCTIONALLY TREATED. Third American Edition, thoroughly revised by the author. 1 vol. Svo. , of over 300 pages, cloth, $3 00. {Lately issaed.)
OOLOMBAT DE L'ISEBE. THE DISEASES OP FEMALES. Trons- lated by Charles D. Meigs, M.D. Second edition, nith numerous iUustrationa. 1 vol. Svo., of 720 pages, cloth, $3 T5.
CARPENTER {WO.. B.) PRINCIPLES OF HUMAN PHYSIOLOGY, WITH THEIR CHIEF APPLICATIONS TO PSYCHOLOGY, PA- THOLOGY, THERAPEUTICS, HYGIENE, AND POREHSIC MEDICINE. A new American edition edited by Francis 0. Smith, M.D. With nearly 300 illustfations. In one large vol. 8yo., of nearly 900 closely printed pages, cloth, $5 50; leather, raised bands, $fi iJO.
id .y Google
HENRY C. LEA'S PUBLICATIONS.
CdRPENTER (WM. B.) PRINCIPLBSOF COMPARATIVE PHYSIO- LOaY. Sea AmeiiBnn, Tram the fourth itnd reiised London edition. With OTBr 300 baaiitifut illustrations. 1 Tol. 6vo., of 752 pages, cloth, $5 00.
PRIZE ESSAY OS THE USB OP ALCOHOLIC LIQUORS IN
HEALTH AND DISEASE. Hew edition, with a Prefaoe bj D. F. Condie, M.D. 1vol. ]2mo. of 178 pages, cloth, fiO cents.
0\RSOK (JOSEPH). A SYNOPSIS OF THE COURSE OP LECTURES ON MATERIA MBDICA AND PHARMACY, delirered in tho Uni- versitj ot Pennsjlvanin. Fourth and revised edition. 1 vol. Svo. . extra oloth, $3 OD.
CHBISTI80K (ROBERT.) DISPENSATORY OR COMMENTARY ON THE PHARMACOPCEIAS OF 8RBAT BRITAIN AND THE UNITED STATES, With a Supplement by R. E. GrifEth. In one Siro. Tol. of over 1000 pages, oontdinlng 213 illustrations, extra elotb, $1 00.
CaURCHat (PLKETWOOB). ON TUB THEORY AND PRACTICE OP MIDWIFERY. A non American from the fourth revised Lon- don edition. With notes nnd additions by D, Francis Condie, M.D. With about 200 illnstrations. In one handsome Svo. vol. of nearly TOO pages, estra olotli, Zi 00 ; leather, go 9(1. ESSAYS OS THE PUERPERAL FEVER, AND OTHER DIS- EASES PECULIAR TO WOMEN. lu one neat octavo voL of about 450 pages, extra cloth, $2 50.
CJHDIEtD. FRANCIS). A PRACTICAL TREATISE ON THE DIS- EASES OF CHILDREN. Sixth edition, revised and enlarged. In one large oetavo volume of ava.ily 800 pages, extra cloth, £5 2!> ; leather, S6 25.
CDOPER (B. B.) LECTURES ON THE PRINCIPLES AND PRAC- TICE OF SUROERY. la one large Bvo. vol. of 750 pages, extra cloth, S2 00.
ClILLERIER (A.) AN ATLAS OP VENEREAL DISEASES, Trans- lated and edited by Fkbekab J. BuiiSTEii>, M.D. A large imperial quarto volume, vith 2G pbtes containing about 150 figures, beauti- fully colored, many of them the she of lite. In one vol., strongly bound in extra cloth, $17. ILatelg piMis/uil.) Same work, in five parts, paper covers, for mailing, $S per part.
CYCLOPEDIA or PBACTICAL MEDICINE. By Dunglison, Forbes, Tweedie, and ConoUy. In four large super rojul octavo volumes, of ■^254 double. columned pages, leather, raised bands, $15; extra cloth, $11.
CIVHPBELL'S LIVES OF LORDS KENYON, ELLENBOROUGH, AND TENTERDEN. Being the third volume of " Campballa Lives of the Chief Justices of England." In one erown octavo vol., cloth, $2.
D^LTOK (J. C.) A TREATISE ON HUMAN PHYSIOLOOY. Fourth edition, revised, ivith nearly 300 illustrations on wood. In one very handsome ootavo volume of about 700 pages, extra cloth, $5 25 ; leather, £B 26.
DE JONGH, ON THE THREE KINDS OF COD-LIVEK OIL. 1 small ISrno. vol., 75 cents. DON QUIXOTE DE lA MANCHA. Translated by Ch.is. Jarvis, Esq., with illustrations by Tony Johannot. In two handsome vols, crown 8vo.,fonoy cloth, $3; plain oloth, S2 50; library sheep, $3 20; half morocco, $3 70.
DEWEES (W. P.) A TREATISE ON THE DISEASES OF FEMALES. With illnst rations. In one Svo, vol. of b36 pages, extra cloth, $3. A COMPREHENSIVE SYSTEM OF MIDWIFERY. In one
id .y Google
:: I'L^ULICATIUNW.
8vo. vol. of nearly 700 large and oloaelj prioted pages, extra cloth, Si; leather, $5.
DTTHGLISON (SOBLET). MEDICAL LEXICON ; «, Dictionary of Medlcul Science. Containing a ooncise explanation of the vnrions Buhjeeta and terms of Anatomy, Physiology, Pathology. Hygiene, Thernreutios, Phanno oology, Pharmoey, Snrgerj', Obstetrics, Medical Jniispradence, and Dentistry. Notices of Climate and of Mineral IfaCers; Formula for OSioinal, Empirical, and Dietetic Preparations, vith the accentantion and Etymology of the Terms, and the French and other Synonymes ; eo as to constitnle a French as irell as English Medical Lexicon. In one veij large royal 8yo. vol, of 1048 double oolamned pages, in small type ; strongly bound in cloth, $3 ; leather, raised bands, $6 75.
HUMAN PHYSIOLOGY. Eighth edition, thorongbly revised.
In two large 8fo. vols, of about 1500 pages, ivith S32 iUustrations, extra cloth, $7.
D'
. Tol. of 770 pages, extra cloth, S4. |E LA BECHE'S GEOLOGICAL OBSERVEB. In one large 8vo
of 700 pages, witb 300 illustrations,
DWIA (IAME8 D.) THE STRUCTURE AND CLASSIFICATION OF ZOOPHYTES. With illuBtretioas on wood. Inone imparial Ito. vol., cloth, $4 00.
ELIIS (BEKJAMIS). THE MEDICAL FORMULARY. Being a collection of presoriptions derived from the writings and practice of (he most eminent physicians of America and Europe. Twelfth edi- tion, carefully revised by A. H. Smith, M. D. In one Svo. rolumo of ST4 pages, extra cloth, $3.
EaiCHSEH (JOHH). THE SCIENCE AND ART OF SURGERY. A new and improved Amerionn, from the fifth enlarged and re- vised London edition. Illnjtrated with over 830 engravings on wood. In one large imperial 8vo. vol. of 1223 closely printed pages, extra cloth, £7 50 ; leather, raised bands, SS 50.
ON RAILWAY AND OTHER INJURIES OP THE NERVOUS
SYSTEM. In one small 8vo. vol., extra oloth, $1.
ENCYCLOPSIDIA AMERICANA. Complete in 14 large Svo. vols Containing nearly 90II0 double columned pages, oloth, ^22, ENCYCLOPEDIA OF GEOGRAPHY. In three large Svo. vols. Illus- tratedwithS3 maps and about 1100 wood-cuts, cloth, $i. FISKE FUND PRIZE ESSAYS ON TUBERCULOUS DISEASE. In one small 3to. vol., ololh, SL FLETCHER'S NOTES FROM NINEVEH. AND TRAVELS IN MESO- POTAMIA, ASSYRIA, AND SYRIA. In one 12mo. vol., oloth, 7Bcts. PINT (AUSTIK). A TREATISE ON THE PRINCIPLES AND PRACTICE OP MEDICINE, Third edition, thoroughly revised and enlarged. In one large Svo. volume of 1002 pages, extra oloth, $B ; leather, raised bands, $7.
id .y Google
HENRY C. LEA'S PUBLICATIONS. G
FLINT (AUSTIN), A PRACTICAL TREATISE, ON THE PHYSICAL EXPLORATION OP THE CHEST, AND THE DIAGNOSIS OF DISEASES AFFECTING THE RESPIRATORY ORGANS. Second nmd revised edition. Ona 8vo. rqi, of 68S pages, olotli, $i 50.
A PBACTICAL TREATISE ON THE DIAGNOSIS ANDTEBAT-
MENT OF DISEASES OF THE HEART. Second edition, enlnrged. Id one neut Sto. voi. of oier 500 pages, $1 00. {Jtisl issued.}
FOWHE (GEORGE). A MANUAL OP ELEMENTARY CHEMISTRY. From the t^nth enlarged English edition. In one rojal 12mo. yol.of S57 pages, >rith 197 illnstra Lions, extra cloth, $2 75 ; leather, $3 25. ■plTLLEE (HENRY), ON DISEASES OF THE LUNGS AND AIR J- PASSAGES. Their Pathology. Physical Diagnosis, Symptoms and Treatment. From the second English edition. la one 8vo. vol. of about 600 pages, extra cloth, $3 50.
QLWGE (GOTTLIEB), ATLAS OP PATHOLOGICAL HISTOLOGY, Translntfld hy Joseph Leidy, M.D., Professor of Anatomy in tha University of Pennsylvania, ftc. In one vol. imperial qnarto, with S20 oopper plnU %nre3, plnia and colored, extra cloth, $4.
eBJlHAH (THOMAS). THE ELEMENTS OF INORGANIC CHEMIS- TRY. INCLUDING THE APPLICATION OF THE SCIENCE IN THE ARTS. A new and enlarged edition by H. Watts and Robert Eridges, M.D. In one 8vo. vol., of over 800 pages, with 332 wood- oats, extra cloth, $5 51). GIBSON'S INSTITUTES AND PRACTICE OF SURGEEY. In two Svo. vols, of about 1000 pages, leather. $6 50. GRAY (HENRY), ANATOMY, DESCRIPTIVE ASD SURGICAL, A new American, from the fifth and enlarged London edition. In one
elaborate engravings 01
ERT E.,
TAINING THE METHODS OF PREPARING AND ADMINISTER- ING OFFICINAL AND OTHER MEDICINES. In one Lirge Svo. vol. of 650 pages, double columos, extra cloth, $4 j leather, $5.
GUIZOT'S HISTORY OF OLIVER CROMWELL. In two royal 12mo. vols. Containing 900 pages, cloth, $2. BROSS (SAMTTEL D.) A SYSTEM OF SURGERY, PATHOLOGICAL, DIAGNOSTIC, THERAPEUTIC. AND OPERATIVE. Illustr.itad by over 1300 engravings. Fonrth edition, revised and improved. In two large roya 18vo. vols, of 2200 pages, strongly bound in leather, raised bands. $15.
A PRACTICAL TREATISE ON FOREIGN BODIES IN THE
AIRPASSAGES. In oneSvo. vol. of 468page3. Extra cloth, $2 7S,
ELEMENTS OF PATHOLOGICAL ANATOMY. Third edition.
In one large Svo. vol. of nearly 800 pages, with about 350 illustra- tions, extra cloth, S4. eUEBSANT (P.) SURGICAL DISEASES OF INFANTS AND CHIL- DREN. Translated by R. J, D.inglison, M. D. {PMishing in the Med. Netcs and Library for 1871.)
HEATH (CHRISTOPHER), PRACTICAL ANATOMY; A MANUAL OF DISSECTIONS, With addition?, by W. W. Keen, M. D, In 1 volume i with 247 illustrations. Cloth, S3 60 ; leather, S4. (J\'ou-
id .y Google
6 HKNRY C. LEA'S I'L'BI.iCATIOrJS.
HARTSHOHHE (HEHE"!). ESSENTrALS OP THE PRINCIPLES AND PRACTICE OF MEDICINE. Seoond and revEaed edition. In one 12jno. rol. of abuut 450 poges, olotb, $2 33; half bound, $2 03
CONSPECTUS OF THE MEDICAL SCIENCBS. Comprising
MnnnalB of Anotonij, Pbysiology, ChemlEtry, Materia Medion, Ptaa- tico of Medicine, SnrgBry, nnd Obstetrioa. In one royal 12roo, toI- ume of over lOOD pngea, nith nbnat 300 illDStratious. Strongly bound in leather, S9 2b ; extra clotb, $4 aO.
MANUAL OF ANATOMY AND PHYSIOLOGT. OneTolnmerojiil
32ino., oloth, $1 75.
Hft.1inLT0H (TSANK H.) A PRACTICAL TREATISE ON FRAC- TURES AND DISLOCATIONS. Third edition, revised. In one handsome 8vo. TOl. of 777 pages, with 294 illnattationB, extia eloth, $5 75.
12mo. Tol. of oier £00 double oolumned pages, eloth. £1 &II; leather, $2.
HODOE (HUGH L.) ON DISEASES PECULIAR TO WOMEN, IN- CLUDINa DISPLACEMENTS OF THE UTERUS. Second and revised edition. In one Sro. Tolnme, oloth, $4 SO.
THE PRINCIPLES AND PRACTICE OP OBSTETRICS. Klua-
trated with large lilhogrnphio plates containing 159 figures from original photographs, and with nnmerous wood-outs. In one large qnarto vol. of 550 double-col a mned pages. Strongly bound in extra cloth, 814.
HOLLASD {Snt HEHBY) . MEDICAL NOTES AND REFLECTIONS. From tbe third English edition. In one 8vo. vol. of abont 500 pages, extra cloth, $3 50.
HODOES (RICHASD M,) PRACTICAL DISSECTIONS. Second edi- tion. In one neat royal l2ino. vol., half bound, S2.
SCRIPTURE QEOGRAPIIY AND HISTORY, imaps. Inlvol. 12mo., oloth, SI.
HOBREE (WILLIAM K). SPECIAL ANATOMY AND HISTOLOGY. Eighth edition, rerised and modified. In two large Svo. vols, of over 1000 pages, containing 300 wood-cuts, extra cloth, £8.
Hm (BERKELEY), SYPDILIS AND LOCAL CONTAGIOUS DIS- ORDERS. In one Svo. volume of467 pages, estm oloth, $3 25. HILLIER (TH0KA8). H4RD-B00K OF SKIN DISEASES. Seoond Edition. In one neat rojal 12u]0. volume, about 300 pp., with two plates, oloth, $2 25.
HAIL (MRS, M.) LIVES OP THE QUEENS OP ENGLAND BEFORE THE NORMAN CONQUEST. In one handsome Svo. vol., cloth, $2 25 ; crimson oloth, $2 50 ; half moroooo, S3. TONES (C. HAMDFIELD), AND 8IEVEKIH0 (E. D. H.) A MANUAL " OF PAT HOLOQIOAL ANATOMY. In one large Svo. vol. of nearly 750 pages, with 397 illustrations, extra oloth, $3 50.
id .y Google
K'
IIF.XRY C. LEA'S PUBLICATIONS. 7
■IEKE9 (WILLIAM SEMHOUSE). A MANUAL OP PHYSIOLOGY, ■ From the third LondoD edition, with 200 illnstrnttons. la one large
12II10. vol. of 5S6 pnges, cloth, $2 25 j leather, $2 75. ITAPP (S.) TECHNOLOGY; OR CHE MI6TEY APPLIED TO THE ARTS AND TO MANUFACTURES, with Araeripan nrtditioiiB, by Pi-of. Walter R. Johnaon, In two 8vo. vols., with 500 illustrations, cloth, $D.
■Jfi'S MEMOIRS OF THE LIFE OF WILLIAM WIRT. In vols. 12mo., cloth, $2.
LEA(HENBTC.) SUPERSTITION AND FORCE; ESSAYS ON TUB WAGER OF LAW, THE WAGBE OP BATTLE, THE ORDEAL, AND TORTURE. Second edition, revised. In one haJidsome rojal 12mo. vol., S2 75. {Laiely istnfd.)
STUDIES IN CHURCH HISTORY. The Rise of the Temporal
Power—BeneHC of Clergy— Escommunication. In one handsome 12mo, vol. of 515 pp., eitra cloth, $2 75. {Lately isaied.)
LAILEMAHD |W.) AHD WILSON (MAKBI9). A PRACTICAL TREATISE OS THE CAUSES, SYMPTOMS, AND TREATMENT OF SPERMATORRHffiA. Translated and edited hy Henry J.
MoDougall. Fifth Amarioan edition. To which ia added ON
DISEASES OF THE VBSICUL^ SEMINALES. With epecial re- ference to (he Morbid Secretions of the Proatntic and Urethral Muoons Membrane. By Marris Wilson, M. D. In one neat octavo volume, of about 400 pages, estro oloth, $2 T5.
LA BOCHE (R.) YELLOW PEVER IN ITS HISTORICAL, PATHO- LOGICAL, ETIOLOGICAL, AND THERAPEUTICAL RELA- TIONS. In two 8vo. vols, of nearly 1500 pages, extra cloth, $7.
PNEUMONIA. ITS SUPPOSED CONNECTION. PATHOLO-
GICAL AND BT OL G TH AUTUM AL FE BRS. In
one 8vo. vol. of 5 p g h $
LAUBENCE [J. Z.) AND HOON BOBERT C AH DY-BOOK OF OPHTHALM UPGER S d hy Mr.
Laurence. With m ol., extra
oloth. $2 75.
tEHMAHH (C. 0.) PH 0 L HE TR T nslated by
George F. Day, M D R E B D , Prof, of
Chemistry, in the University of Pennsylvania. With plates, and nearly 200 illnatrationa. In two large Svo. vols., containing 1200 pages, extra cloth, $6.
A MANUAL OF CHEMICAL PHYSIOLOGY. Translated with
notes and additions, by J. Cheston Morris, M. D. With an Intro- dnctory Essay on Vital Force, by Prof. Samuel Jackson. In one very handsome 8vo. vol. of 336 pages, extra cloth, S2 25. TAW80N (BEORGE). INJURIES OF THE EYE. ORBIT. AND EYE- Xl LIDS, with about 100 Uluetrations. From the last Engliah edition. In one handsome Svo. vol., estra clolh, $3 50.
LUDLOW |J. L.l A MANUAL OP EXAMINATIONS UPON ANA- TOMY. PHYSIOLOGY, SURGERY, PRACTICE OP MEDICINE, OBSTETRICS, MATERIA MEDICA, CHEMISTRY, PHARMACY, AND THERAPEUTICS. To which is added a Medical Formulary. Third edition. In one royal 12mo. vol. of over 800 pages, extra cloth, $3 25 ; leather, $3 75.
L&YCOOS (THOMAS). LECTURES ON THE PRINCIPLES AND METHODS OF MEDICAL OBSERVATION AND RESEARCH. In one 12mu. val,, exlra elolh, SI.
id .y Google
HENRY C. LKA'S PUBLIC ATIOKH.
tYNCH (W, F.) A NARRATIVE OF THE UNITED STATES EX- PEDITION TO THE DEAD SEA AND RIVER JORDAN. In one large and handsome odUvo vol., nitli 2S bcnatiful plutes and two maps, ololh, S3.
Some Wort, condensed edition. One Tolnme rojal 12mo., estn
oloth, $1.
LYONS (BOBEBT D.) A TREATISE ON FEVER. In one neat 8vo. vol. of 362 pages, extra cloth, $2 25.
MARSHALL (JOHH), OUTLINES OP PHYSIOLOGY, HUMAN AND COMPARATIVE. With Additions by PhJncis G. SiEirH. M. D., Profeaaor of the Inatitutes of Medicine in the University of Pennsylvania. In one Svo. volume of 1026 pages, with 122 illustra- tions. StroBgty bound in leather, raised bands, $T SO; extra cloth, 16 60.
'ACXISE (JOSEPH). SUKGICAl ANATOMY. In one large Im- - perial quarto vol., "nith OS splendid plates, haautifnlly colored; con- taining 190 figuiea, many of them life size, extra oloth, $14. 'ACKENZIE (W.) A PRACTICAL TREATISE ON DISEASES AND
■ INJURIES OP THE BYE. In one handsome Svo. vol. of 1027 pages, with plates and numerous wood-outs, estra oloth, $B 50.
■EIGS (CHAS. D.) OBSTETRICS, THE SCIENCE AND THE ART.
■ Fifth edition, revised, with 130 illustrations. In one beautifully printed 8vo. vol. of 760 pages, eMra cloth. $5 50 ; leather, Sfi 50.
WOMAN ; HER DISEASES AND THEIR REMEDIES. Fourth
and improved edition. In one large Svo. vol. of over 700 pages,
extra oloth, $5 ; leather, SO. ON THE NATURE, SIGNS, AND TREATMENT OF CHILD-BED
FEVER, In one 8vo. vol. of S65 poges, extra oloth, $2. ILLEH (JAMES). PRINCIPLES OP SUR8EBY. Fourth American.
from the third Edinburgh edition. In one large Svo. vol. of 700
padres, with 240 illustrations, extra cloth, $3 75.
— THE PRACTICE OP SURGERY. Fourth American, from the
last Bdinbui^h edition. In one large 8to. vol. of 700 pages, with
364 illustrations, extra eloth, 33 75. 'OKTOOUERY (W. F.) AN EXPOSITION OP THE SIGNS AND
SYMPTOMS OP PREGNANCY. Prom the second English edition.
In one handsome Svo. vol. of nearly 600 pages, extra cloth, S3 76.
MORLAHIKW, W.) DISEASES OF THE URINARY ORGANS. With Illustrations. In one handsome Svo. vol. of about 000 pages, extra cloth, $:s 50.
MOKLAKD (W,W.) ON THE RETENTION IN THE BLOOD OF THE ELEMEISTS OP THE URINARY SECRETION. In one vol. 8vo., extra cloth, 75 cents.
MULLER (J.) PRINCIPI.ES OF PHYSICS AND METEOROLOGY. In one large Svo. vol. with 550 wood-cuts, and two colored pl.ites, cloth, £4 50,
MIRABEAU; A LIFE HISTORY, In one royal 12mo, vol., oloth, 75 cents.
MACFAELAHD'S TURKEY AND ITS DESTINY. In 2 vols, rojiil 12mo., cloth, S3. MARSH (BBS.) A HISTORY OP THE PROTESTANT REFORMA- TION IN FRANCE. In 2 vols, royal 12mo., extra cloth, $2. NEIH (JOHN) AND SMITH (FRANCIS G.) COMPENDIUM OP THE VARIOUS BRANCHES OF MEDICAL SCIENCE. In one bandsome 12mo, vol. of about 1000 pages, with S74 wood-cuts, extra eloth, $4; leather, raised bands, $4 75,
M"
M'
id, Google
iiEXltV C. LI-;A'« FUBLICATIOXS. ti
NELTGAN (J, MOORE). A PRACTIOAt, TREATISE OS DISEASES OP TQB SKIS. Fifth Amerlonn. from the second Dublin edition. In one uent royal 12mo. vol. of 462 pag«e, extra ctoth, $2 25.
AN ATLAS OF CUTASEO0S DISEASES. Ii. one hnndsnme
qnarto vol. willi beautifnlly colored plates, &o., estrn cloth, gS 50.
NIEBUHB (B. G.) LECTURES ON ANCIENT HISTORY i com- prising the history of tha Asiatic Nations, the Egjptianfl, Greeks, Mnoedonians, and Cftrthneenions, Translated by Dr. L. Schmitz. In three neat volumcE, croirn octavo, oloth, $9 00.
ODIING (WILLIAM). A COUKSB OF PRACTICAL CHEMISTRY FOR THE USB OF MEDICAL STDDENTS. Prom the fourth revised London edition. In one 12mo. vnl. of 261 pp., with 75 illus- trations, extra cloth, $2. {Latehj issued.) PiTY (F. W,| A TREATISE ON THE EDNCTIOS OF DIGESTION : ITS DISORDERS AiSD THEIR TREATMENT. From the second London Ed. In one Svo. vol. of 24epp., est. cl., S3. {Latelg iis^ied.)
PAKBISH (EDWABD). A TREATISE ON PHARMACY. With many FormnliB and Presoriptiona. Third edition. In one hnndaome 8to. vol. of 850 pages, with several hundred illustrations, e.rtra cloth, S5.
PIBRtE (WILLIAM). THE PRINCIPLES AND PRACTICE OF SUR- GERY. In one handsome octavo volume of 7S0 pages, with 316 illustrattons, extra elotb, £3 75.
PEOEISA (JONATHAK). MATERIA SJEDICA AND THERAPEU- TICS. An abridged edition. With numerous additions and refe- rencee to the United States Phatmncopceia. By Horatio C. Wood, M. D. In one lar^e ootavo volume, of 1040 pages, vith 2ii6 illustin- tions, extra oloth £7 DO { leather, raised bands. £8 DO.
FDLSZKY'S MEMOIRS OF AS HUNGARIAN LADY. In one neat royal I2mo. vol., extra cloth, SI. PAGETS HUNGARY AND TRANSYLVANIA. In two royal 12mo, vols,, oloth, $3. EOBBBTS (WILIIAW). A PRACTICAL TREATISE ON URINARY AND RENAL DISEASES, With numerous illustrations. In one very handsome Svo. vol. {New tdilum preparing.')
EAMSBOTHAM (FE*HCIB H.) THE PRINCIPLES AND PRAC. TICB OP OBSTETRIC MEDICINE AND SCIRGERY. In one im. perial Svo. vol. of 660 pages, with 64 plates, besides numerona wood- cuts in the text. Strongly bound in leather ST. EIOBY (EDWARD). THE CONSTITUTIONAL TREATMENT OP PEMALE DISEASES. In one neat royal 12mo. vol. of about 250 pp., extra cloth, $1.
A SYSTEM OF MIDWIFERY. Second American edition. In
one handsome Svo. vol. of 422 pages, extra cloth, $2 it.
EANKE'S HISTORY OP THE TURKISH AND SPANISH EMPIRES in the 16th and beginning of 17th Centnry. In one Svo. volume,
HISTORY OP THE REFORMATION IN GERMANY. Parts I.
IL III, In one vol., extra cloth, $1.
EOYLE (J, FORBEi:). MATERIA MEDICA AND THERAPEUTICS. Edited by Job. Carson. M. D. In one large Svo. vol. of about 700 pages, with 9S illustrations, extra eloth, $3.
EtDCLIPFE. AINBTIE, AND OTHERS. ON DISEASES OP THE SPINAL COLUMN AND OP THE NERVES. ] vol. 8vo., extra cloth. 11 50. {Jau issiiei/.)
id .y Google
id, Google