.\S;:\I~YTIC.\ CIfIbIIC.\ :\CT.\ 317

Tn the lxcscnt invcstigution an attempt 1~1s lxxm nx~cl~ to clctc*rrninc irlclircctly llyclrogcn lxx-osidc, lead diosiclc, inangancsc tliosidc, sclcnium tlioxidc, sodium formate, sodium sulphiclc, sodium mctavanadatc, potassium iodatc and copper sull)llatc by a volumetric method, using chloraminc-13 as an osidizing agent.

In all titrations with chloraniinc-13, 5 ml of 0.02Jf iodine monocliloriclc, 5 ml of cllloroform and enough of hydrochloric acid to keep its normality bctwccn 4h’ to 5:V wcrc added to tllc titrant in ;L conical flask. Chloraminc-I3 was aclclccl from a burcttc until the solution, whicll was colourcd with iodine, bccarnc pale yellow. The conical flask was then stoppcrcd and vigorously shaken. Addition of small volumes of chloraminc-I3 solution WLS continued, shaking vigorously after each addition, until the chloroform layer was faintly violet. The reagent was then added dropwisc, with shaking after the nclclition of each drop, until the chloroform layer cliangcd its colour from violet to light p;~lc yellow. The end-point was very shaq>.

Hydrogen peroxide reacts with arscnious osiclc in alkaline medium :

As,O, + 2 I-1,0, -= As,O, -I- 2 l-I,0 .,

A known weight of llydrogcn ])crosidc was taken in :I conical flask and LL known csccss of arscnious osidc dissol\*cd in ten p’cr cent. sodium hydrosidc solution was aclclcd to it. The misture WZLS :~llowcd to stand for a couple of minutes ancl acidified with concentrated hydrochloric acid. 5 ml of o.oz:ll iodine monochloriclc and 5 ml of chloroform wcrc :~cldecl to it. The conical flask was stoppcrcd and tlic misturc was vigorously sliakcn. The csccss of arscnious osidc. left unreactcd in the misturc, was dctcrmincd by titrating it against standard chloraminc-l3 solution. i\s,O, -I- 2 C,H,SO,N (Na)Cl + 2 I-I,0 =--= As& -I- 2 C,‘H,SO,h’I-I, -I- 2 N7aCl The results arc given in Table I.

_ .

1v/ IO .4h20:, A?/ 10 Chlornm- inc-13 uscrl

-VI I o As@, ;1tltlecl usal by H,O,

l-1,0, founcl

for cxccss As,On .__- .

III 1 ml ml &T

rg*oo ‘1.00 11 .oo o.oxs7 17.00 “-7.5 r4.2.5 0.02‘12 20 00 1.65 Js.35 0.0312 3G.00 2.80 33.20 0.0565 SO.00 3.60 _\G*‘}O 0.0789

. .

Potassium iodide reacts with the diosidcs in 1)rcscncc of concentrated hy- drochloric acid :

KI -I_ PbO, -I- -1 I-ICl ::: PbCl, -t_ KC1 -I- ICl + 2 I-I,0 KI -b MnO, -k 4 T-ICI =- MnCI, -I- KC1 -I- ICl -t_ 2 I-I,0

In prcscncc of hydrochloric acid, potassium iodide reacts with chloraminc-B :

I<1 -}- C&SO,N(Na)Cl -k 2 I-ICl = ICC1 -/- NaCl + ICl _1- C,I-I$O,NM,

A known weight of tlic clioxidc was taken in a conical flask and a known esccss of potassium iodide solution was ad&cl to it. The mixture was acidified with hydrochloric acid to keep its normality bctwccn L1N to gN. 5 ml of 0.02iU

ioclinc monocl~loriclc and 5 ml of chloroform wcrc added to it. The cxccss of iodide was titrated back with stanclnrcl chloraminc-I3 solution. The results arc given in I’ablcs II and III.

.- - - ---- __- _._-- . -- -.._ . __ _ _ _ _ . . _ -. . .--_ _

X%0.. tn1teIi

N/20 I<1 X/I0 Chlornminc-U :1tlclccl usccl for csccss ICI

M/20 KI l?bOa founcl usccl by l’l,Oz

-_._-. _. ._... _ _ . ._ .__. _... -. -- .

6 ml ml ml g

O.O‘I30 8.00 4.40 3.60 0.0.130 0. r2go I.fj.00

z’o.00 <I .2’0 lO.YO 0. I”01

0.13 16 $00 TT.00 0.182‘1

0. I3 IG

L5.00 9.70 15.30 0.1829 O.?,gY‘I 30 00 S..{O 2 r.60 (3.2533 --. .

VOL. 11 (1)5_1) O_sII~..\~fIOS-I1EDUC’rIOB RI3:\CTIOss II

TABLE III

MnO, taken

._.. -. _._ . ..- . - ..--_ .- -.-- -.. _ ..-. ..-

,v/20 I<1 X/I o Chloramine-B M/20 I<1 MnO, ndclccl Llsccl for CXCCSS ICI uscd by MnO, found

319

D

. . .--...

lz ml ml

0.0325 IO.00 2.5’ o.oqSo 20.00 s.9s 0.084s zg.00 .5*.5o O.IIGY 30.00 3.15 _.-.._-. _- _.___ . .-- . ..-. -- - -

~rtcr~rlinc~iion oi sclenitrwt dioxide

Sclcnium cliosidc reacts with hyclrazine sulphute according to the equation :

ScO, -}- N2H, = Se + N, + 2 N,O

In acid medium hydrazinc sulphatc reacts with chlornminc-13 :

N,‘II, -t_ 2 C,H5S0,X (Nn)Cl - N, -t_ 2 N:iCl + 2 C&J,SO,N’I-I,

A known weight of sclcnium clioxiclc w;~s clissolvccl in minimum quantity of hot water and a known cxccss of M/r0 hydrazinc sulphatc solution was aclclccl to it. The misture was heatccl to boiling. Sclcnium that sc~pi~ratd was rcmovccl by filtration. The unused hyclraxinc sulphatc in the filtrate was titrntcd against stanclarcl chloramine-I3 in prcsencc of hyclrocldoric acid, 5 ml of o.ozA,1 iodine monochloridc and 5 ml of chloroform. The results arc rccorclctl in Table IV.

*l-AT3 T-T3 T V

sco, taken

M/lo N,H,H,SO, N/IO Chloraminc-13 11l/ro N,T&H,SO, added usccl for cscess

N2H4H2S0,, usctl by sco,

- _.. _

b’ ml ml ml

0.0777 10.00 X2.00 j.“” O.Oc_)CJ(j 12.00 X2.00 0.00

0.1330 rg.00 12.00 12.00 O.IGGO 20.00 ‘20.00 15 00 0.2040 2g.00 20.Zj0 lY..IO

- _- ._..

Ddcr)ni~w~tion o/ sodium /orrr~!rt~

Soclium form&c rccluccs mercuric chloride to mT1crcurous cllloridc*:

I-ICOONa + 2 HgC1, :-= H&Cl, -I- XaCl -}- HCl -j- co,

. SCO,

found

6

0.0777 ~J.O‘XKl 0.1332

o.rGGg

0. ‘042

320 13. sIx(;lI, I<. c. SOC)D VOL. 11 (1954)

In prcsrncc of hyclrocl~loric acid, chloraminc-13 oxidizes xncfcurous chloride to mercuric chloride :

I-Ig&l, -I- CJ-I,SO,N (N&l -I- 2 I ICL :: 3 I l&l, -{- NaCI -j- C&SO,NI-I,

A known wciglit of sodium formntc was taken in a conical flask. Some soclium acctatc solution, a11 csccss of saturatccl mercuric chloriclc solution and enough ol wxtcr to m;il;~ the volume to :~lx~~t. 75 ml wcw aclclccl to it. ‘I’llc misttlrc was

11(~atccl on ;I steam Ixltli for about two lwurs until tlic whole of c:irlxm tliosidc was cvolvccl. ‘1’1~ Tlask was cooled ancl tlw Ix-ccipitatccl mercurorls cllloridc fil- tcwcl. ‘I’hc l)rccil~itatc illOl1~ with tlic filter l)xlxr w;iS triuIsfcrrd to a conical flask, ancl titrxtccl against st:Ll~d:lrd chloraminc-B solution ztftcr the addition of l~yclrochloric acirl, iotliiic: monocliioritlc and chloroform. ‘I‘tic results arc given in ‘l’ill>lC 1’.

--- ------.- .--. . - - -. .._ ..-- . -__________-_ ---_- _._. . -_ ._ ______- _... . . . . __ ._ -

HCOONa N/I o Chloraminc-I3 IICOONiL l_iLlCC!n IlSCd found

---.----.------.-- ----- - .--. -- _.__ .-_ .- _.._ ---_-_____._ . .-_ _ ._-__- -._ -.-- __ .-

b’ ml 6

0.0x36 4.00 o.or3o 0.0204 (3.00 0.0204

0.0340 10.00 0.0476

0.0340

0.0680 14.05 o.od+78 19.95 0.0678

----- .----._ --.---___ - .--- ----_ -. - .- _____ __-- --_____ _. _ __ ______ .- _. . _ _. _ _.._. -_-_

Socliunl sulpliiclc reacts with iLrScnious oxide. in prcscncc 01 l~yclrocliloric acid:

3 Nu,S -I- As,O, -I- G I-ICl = L&S, -I- 6 NnCl _1- 3 I-1,0

Arscnious osidc is osiclisccl to arsenic osidc by chloraminc-B in acid medium :

k&O, -I- 3 C,,I-I,SO,N (Na)Cl + a I-I,0 = As,O, -t- 2 NaCl + 2 C,H,SO,NH,

I.5000 g of sodium sulphidc wcrc dissolved in 100 ml of water and a known csccss of arscnious osidc (z.505S g) dissolved in sodium hydroxide was added to it. The misturc was thoroughly stirred and acidified with dilute hydrochloric acid, when yellow prccipitatc of nrscnious sulphide was formed. The precipitate \vas filtcrcd, wasl~ccl with water and the filtrate made up to 350 ml. The cscess of arscnious oxide prcscnt in the filtrate was determined by titrating it against standard chlornminc-1’3 after the addition of hydrochloric acid, iodine monochlor- iclc and chloroform. The results arc tabulated in Table VI.

. ---. -_ _. _- __....-. - -.-.- --.- ._.__-- __ -~ -.-__

Na,S Filtrate .,V/ I o Chloram- taken taken for inc-13 used

A%%

titration for As,O, in 250 ml

of flltratc -. - _ -.._ ---. _ ..- - -- ------ _---. _____

s ml

LO.00 20.00

I .jOOO 20.00

1,0.00

_ _ _._ _ _ __ __-. __ ..-. .._ -

Dctcrrrrintrtion of sodium

Scxlium mctav;mwl~~tc~ rnccliurn :

ml b’

20 00 dO.OC> I .“370 :0.05 LO.00

. .

rrr~t~tv~lrltrrl~llc:~

---._ __.-. - ._-.- __-.. As-O, u&l

NazS found

by Na2S .- _

6 fs

I. zGHH I .5000

. -.

rcxcts with hydrazinc: sulpllatc~ in l~yclrocl~loric acid

N,H,, -}- _I NiXCIS -{- ‘12 MC1 :-. _F VOCI, -t -1 NaCl -I-- S L-I,0 .-I- N,

In Ix-cscncc of llyclrocl~loric acid. cl~lornminc-13 osiclizcs liydrnzinc sulpllntc :

.&I-I,, -{- z C,,I-I,SO,X (Sn)Cl =:- 2 NnCl -t_ :! CJ-IGSO,NI-1, -1_ N,

_A known wcigl~t of sodium mctavanaclatc was taken in a conical flask, ;L known csccss of stnnclarcl liyclrazinc sull)hatc solution and enough of concentrated hydrochloGc acicl to lcccp the normality of acid bctwccn (7X to 7.5N) were adclccl. ‘The misturc \viLs vigorously shaken. ‘The csccss of hydrazinc sulpliatc left un- reacted was titrntctl back with stanclnrd cllloraminc-L% after the addition of ioclinc n~onoc1doridc and chloroform. Tlic: rcc;ults ;ux rccordccl in Table VII.

SODIUhI iSIETAVANAUA1’E

__ -___ .._ .__ --__--- -_- __.._ --_-~ _ __-----_ .-__ __ -_-_ NnVO, M/40 N,H,$J,YO, lV/ I o Chloraminc-J3 M/40 NJ,H,H,SO, NaVO, lxlkcn XlClCd iiwxl for c.xcesb nsetl by NnVO, found

N,H,H,SO, _ - . ._ _ ---_. -- _- - _.._.. _ . . . -. .-._.-... . ..-.- -- ..__ -.. - _. _- - ..-..

6 ml ml ml 6

0.1221 IY.00 s.00 10.00 0. I220

0.2198 25.00 7.00 rs.00 o.zrcJG 0.3050 30.00 5.00 Z5.00 0.3050 0.3904 ’ 40.00 8.00 32.00 0.3904 0.4YSo 45.00 -1.98 40.02 O.L+&wZ

_._ ._..__. --.a- --. __ ___. --_ - ._ -_. _...._ -...__ -..- . -- _ . .._ -_.-__-.-- _..-_. ___._.

Pot:tssiurn iod:Lic reacts with nrscnious osidc in prcsencc of hyclrocllloric acid:

.AS,O:, -I- WO, -I- z I-ICl =-= As,O, + KC1 + H,O -t_ 1Cl

In I~ydrocl~loric acid medium chlornminc-I.3 reacts with arscnious osidc:

As,C$ -I- ‘;! CJ1,SO,N(Na)Cl -I- 2 I-I,0 =-z As,O, -+- 2 NaCl -I- 2 CJ-J,SO,NIf,

A known ;unount of potassium ioclatc W:LS taken in a conical flask and a known ~‘xccss of alscnious osidc dissolved in ten per cent. sodium hydroxide solution WLS added to it. The misturc WELLS aciclificd with concentrated hydrochloric ;lcid to Icccl~ the normality between IN to $V. ‘l’hc mixture was vigorousl\ shalccn. Tl:c cxccss of arscnious oxide left unrcnctcd was titrated back with stan- (lard cllloraminc-U solution after the acldition of iodine monochloridc and chloro- loml. Tlic results ill32 given in ‘I’:111lc VIII.

PO rhssxuhl IOLlATE

N/I0 Chloraminc-7% usccl for C’SCCSS

M/q0 R+O:, IlSCd by

AS30:, Ji. LO,, . . _. ._._ . .

ml 1111

7.35 4 .fis s.35 (i&g

I0.W 0.32

13.00 1 ‘.OO

1.5.3.5 I.1 .Gg

X10, f0t111c1

R

o.orqg 0.0356 o.oqc)qa

o.oGq 2 O.Oi84

A known wcigllt of copper sulphatc wns dissolved in water and saturated with sulphur diosidc gas. The solution was boiled and a known csccss of standard potassium thiocyanatc was added to it.

2 CUSO,~ -(- 2 KCNS -I- SO, -t_ 2 I-I,0 = Cu,(CXS), -t_ z I-I,SO,, -I- K,S04

The prc*cipitatcd copper thiocyanatc was filtered. The filtrate was boiled in an atmosphcrc of CO, till free from sulphur diosidc gas, diluted with water to :L kno\vll volume and titrntcd against standard chloraminc-I3 nftcr the addition of hydrochloric zzid, iodine monochloridc and chloroform.

2 I<CNS-+G C,l-I,SO,N(Nn)Cl+-S I-I,0 =--z 19ISO,+G NrrCl+G C,H,SO,NIi,+z I-ICN

Tllc results ;\rc given in ‘I’iLl>lc IS.

OSID.\l (OS-I~i<I~UCTIOS III:.\C’I’IOSS I I 323

TABLE IS

COPPElZ SULPHATI:

.-. _. . _ . . __. .-. __ --.__ ._ .._ . _.. CuSO,.~H,O M,/Go KCNS AT/ 10 Chloramine-B &~/GO KCNS usccl CuSO,.51-1,O

taken aclclccl used for escess KCNS by CuS0,.5H,O found . _ .- ._..

From the results given in Tables I to IS, it is evident that chloraminc-13

can bc used ;LS x volumetric reagent to estimate indirectly, hydrogen pcroxidc,

lend diosidc, mangnncsc dioxide, sclcnium dio.xidc, sodium formntc, soclium sulphidc, sodium mctavanndntc, potassium iodatc and coplwr sulpllatc.

Chloraminc-I3 has been uscfl as an oxidizing agent in hydrochloric acid metlium for the indirect volumetric estimations of hydrogen pcroxicle, leiltl clioxicle, manganese diosiclc, sclcnium dioxide, sodium formntc, socllum sulphltlc, socllum mctnvanaclate, potassium iodatc anal copper sulphatc using iocline monochlor~tlc ar. ~1 catalyst and prc-osicliser. Chloroform is used as an indicator. It is colourccl pink owing to the lib- eraiion of ioclinc clurlng the titration and becomes light pale yellow at the cncl- wint because of the formation of Iodine monocliloridc.

La chloramine-I3 pcut ftrc utllisk conimc osyclnnt, cii solution clilorllyclrique, pour le closage volum6trque inclirect dcs ComposGs suivunts: perosyde cl’hyclro~~ne, biosycle de plomb, biosyclc clc mangan6sc, bioxycle clc s6l&xlum, formiatc clc sodium, sulfurc clc sodium, mCt.nvanaclatc cle sodium, ioclatc clc potassium et sulfate cle cuivre. On utilisc pour cctte cl6termination lc rnonoclilorure d’ioclc coxnnie catalyscur et pr&osyclant, et le chloroformc comme inclicnteur. Ce clcrnicr se colorc cn violet par l’loclc hblr6 pcnclant la titration ct clcvicnt jaunt p~~lc au point fillxl, lxw for- mation de monochlorure cl’ioclc.

ZUSAMMENFASSiUNu’C;

Dns Chlorrrmin-B lcnnn in salzsaurer Liisung nls Os~cl~Ltionstnittcl vcrwcnclct ~~rclen ftir die inclircicte x~olumctrischc Bestlmmung folgenclcr Vcrbinclungen. Wasscrstoffperosycl, Uleicliosycl, Magnesiumcliosyd, Selencli6xyc1, Natrlumformint, Natriumsulficl, Nntriummctnvanadatc Kaliumjoclat, 1Cupfcrsulfnt Fur dicsc Ue- stimmung wircl clas Joclmonochloricl als Katalysator und vorosydiercndes Mittel, uncl clas Chloroform als Inclikator verwenclct. Dieses letztc fiirbt sich viol&t clurcll clas wiihrencl clcr Titration frci gcwordene Joel uncl wrtl tlann sch~~-r~cl~ gelb bcim Enclpunlctc; clies durch Rilclung von Jodn~onocl~loricl.

Reccivecl Tvkircli rsth, 1354