-treated, or by tit rat ion with a <an,kir4 r>
ferrous ammonium sulphate* or ^Ki^ 44r^>u
2HMn04 -f

e ape-it Mich

:iri u

Dete
ing solution

(a} Potassium pertnatt-gan<it< .s ,.',.*,
gin of manganese by the folknvin „ Tt

KMnO4 + 5FelXOa)s -f 8HM I —.

11 < MI din s?.

d i:

Jc t*

- if 1

"I, M» - 41! i
Standardize against ferrous
directed on page 68, Part I.

(b) Ferrous amnioitiutn aul^h i*t %,; < . i +j f
equivalent to that of tiie potassm H ptrn.a- fi^.at*-
50 cc of concentrated sulphurs iuid » ,UM V
standardized by blank titratioiib at tie tu«t t i* IT
of manganese.

(c) Nitric Add, Specific Gmrifj LLt~-~~l> 4u* > j \o ^*i,
centrated acid with three volumes o* uuUr.

(d) Nitric Add, Specific Gra^ly I Olo.~I)J jtt *1 -t*- v * ^
ceatrated acid with 100 volumes of \\attr.

Ignite 1 gin of soil gently in air until al or« >r*<* n.itttr i- i
the ignited soil as directed for the aiileon dtttnmiuit, i, j -
the fusion is perfectly fluid plain the cooled rrae>It on ;t& -
casserole and add nitric acid c until t lie »di 1,1. jurh
Rinse and remove.tlie crucible and tvaporatt4 tit MI atiun tc. dni t^x c^ +|
steam bath. Finally take up \\ith 5(1 ei of i.itnc avid ( . Ht\*t to a i ^i
solution but do not evaporate much of tht ae'd O>i>l, add about iU" #*i
of sodium bisrauthate and stir. A^ttr It) inlr-jtos acid ,V) cc of nlt-Ii at* d
(d) and filter the whole through a GotH'h Mlttr, usrirg&uttion. .\fttrftir-
ing? wash the beaker and crucible with 5(1 cc of the sane Ritr.e iu .
From a burette add to the filtered solutior 45 ce 'mort if netts-a.ry to
reduce all permanganate) of ferrous ammornini j^u'p^iatt. fc-olufor. ^ T* i
permanganate is reduced and t.lit re is an t.\ct.ss of ferrous salt prti*,&t.
Titrate this excess to a faint pink color with standard potassium perman-
ganate solution (G).

A blank determination Is made, using 50 cc of dilute nitric acid, 50 ce of
nitric acid (d) and 0.25 gm of sodium bisniuthate. Filter through a^best***
and wash with 50 cc of nitric* acid as in the previous determination.
From a burette add 35 ec of ferrous ammonium sulphate solution arid
immediately titrate with the standard potassium permaiifciiuite. The
difference between the volumes of permanganate- required for the blank and
• the manganese determination, respectively, is that equivalent to manganese
in the sample of soil. Calculate the per cent of manganese.

If:)

n/ r

it;
f*
fi
M