STUDIES 1N OXIDATION-REDUCTION REACTIONS I. OSIDATION WITH Cl-ILORAMINE-B, IODIKE RIONOCHLORIl~I~

R-IETIIOD

Al:ASAS’IiVl rcportecl that clilornmine-IS is ;L good substitute for cllloraminc-‘l’ in ;m:~lytical chemistry.

In acid medium potassium iodide, nrscnious osiclc, tartar cmctic, mcrcurous chloride, stannous chloriclc, pot;Lssium thiocynnntc, ferrous ammonium StlIpI~i~t~, hydrazinc sulphatc and l~ydroquii~onc react with cllloraminc-13 xcording to the following ccluations: KI --j- C,I-T,SO,N(Nn)Cl -t_ 2 I-ICI = KC1 -t_ ICl -I- NaCl -{- C,II,SO,KI-I, As,O, -t_ z C,I-I,SO,N (Nn)Cl + z I-I,0 = As,O, _1- 3, N&l -+ z C&,SO,N II, Sl,,O, _t- z C,I-I,SO,N(Na)Cl + z H,O -- Sb,O, -t_ z NaCl --I- 2 C,H,SO,NI-I, I-i&& + C,,HGS02N(Nn)C1 -I- :: I-EC1 - z l-l&l, + N&l -+ C,I-I,SO,NII, SnCl, + C,lI,SO,N(Na)Cl - j- L? Z-ICl == ‘SI~C~,~ $- NaC:l -I- C,l-IGSO,NH, 2 KCNS f- G C,HGSO,N(Xr;l)C1 + 8 l-r,0 = 2 KHSO, +- ‘7 I-ICN -+- 6 KaCl -i-

6 C,I-I,SO,N IT, 6 FcSO,, + 2 CJI,SO,N(Xa)Cl + G I-ICl = 2 Fc,(SO,,), + 2 FcCl,, -+

3 N&i -I- 3 C,lI,SO,NI-I, N,I-I, + 2 C,l-I,SO,N(Na)Cl = N, + 2 NaCl $- 3 C,l I,SO,NI-I, C,I-IJON), + CJ-I,SO,N (Na)Cl = C,I-IaO, + NaCl + C,I-I,SO,NI-I,

A known weight of each substance was taken in a conical flask and about 25 ml of water, 20 ml of conccntratcd hydrochloric acid, 5 ml of o.ozJd iodine monochloride and 5 ml of chloroform were added to it. T11e misturc was titratccl against standard chloraminc-B solution. The rcagcnt was added from a burette until the solution, which was colourcd with iodine, became pale yellow and the chloroform layer acyuircd purple colour. The conical flask was stoppcrcd and vigorously shaken during the titration. Addition of small volumes of the chlor- amine-B solution was continued, shaking vigorously after each addition, until the chloroform layer was faintly violet. The chloraminc-B was then acldccl drop- wise, with shaking after ihc addition of ~~11 drop, till the chloroform layer bccamc light pale yellow. The end-point was very sharp.

314 JZ. SINGJI, I<. C. SOOD VOL. 11 (1954)

In thcsc titrations normality of the solution with respect to hydrochloric acid

was kept between 4N to gN. Scvcral titrations were performed in each cast. From

the volume of chloramine-13 used, corresponding to the end-point in each titration,

the amount of substance was calculated. The results are rccordcd in the following-

tables.

o.oYgo O.IZ‘(5

O.lGGO

0.2158

0.3735 -.--

I’o’rAssIurvf IODII>Iz - _ _. _ -. _-..

L. 1020N Chloramine-13 used lil -f&md ml 6 _._ g.80 0.082g

14.72 o.rz45 19.62 0.16Go 25.45 0.2155 44.15 o-3737 -- ___.__. ___--._- -..-_- --.

TABLE II

AIZSENIOUS OXIDE __ - .--._-._.----.-. -- --- ---_-._---

As,O, taken o. 1020N Chloramine-B used As,03 found 6 ml g .- _ . ._ _. _ ._ ._ ._--._------ _ -_._- - - -- - -_. . . .._-

0.0495 9.80 0.0494 0.0891 17.65 0.0890 0.1237 24.35 0.1228 o. I 830 3G.20 0.1826 0.2374 47.05 0.2373 . __. ___-_- _ . _

TABLE III

TARTAR-EMETIC . .._._ -_----_---- .--- - __________. --- --.-. Tartar-cmctic o.ogggN Chlornmine-B usecl Tartar-cmctic

tX1lCCm found 6 ml 6 _ ___._ --_._-__. _ _._. ._ - _ . _ ..-..

0.166g 10.10 0.1676

0.3338 20.15 o-3346 0.4182 25.20 0.4185 0.5507 33.20 o-5513 0.7520 45.30 0.7523 __ ____._ ----

TABLE 1V

MISHCUlZOUS CHLOltIDI2 - _ ._-_. - _... ---- _-_--- ___-~ -_---.---.-.--

Hg&l, taken o. loooN Chloraminc-B usecl H&Cl, found g ml 6

o.xsss 8.00 _ __ .---- ..___ ._ ._.-

0.1889 0.2300 10.00 0.2361 0.3540 15.00 O-3541 o.grg2 22.00 0.5‘94 0.7080 29.95 0.7070

OXIDATION-REDUCTION REACTIONS I 315

TABLE V

STANNOUS CHLORIUE -- _- _... ._-- .~---.-~-_---.---__

SnCl,.2H,O o. I oooN Chloraminc-13 used SnC1,.2 H,O taken fou ncl

fz ml 6 _-.__-._ . _--------I-- _ __________. . _ ._.____... . _ ._....._. ._._. -.- ._.. - _.. .__-. _ .--- _

o.rr30 10.00 0.1128 0.2034 1 s.00 o.zo30 0.2825 25.05 O.ZSLG 0.40G8 30.05 0.4067 0.5085 45.07 0.5o85

____. .__. ------.__-- . .._._ ~ _______ ___. - .__ __.. __- -- .___ -._- _ .-__ .--. _..- _.__ - _-_.

TABLE VI

POTASSIUM THIOCYANATE ----- _--__--__. -_----_--_-__. -_ ._ ______ __.

KCNS taken 0.1056N Chloraminc-B used ICCNS found 6 ml 6

------ .- -___--- -_-._----__-_. _..- - _.--_-_ O.OIGZ 9.45 0.0162 0.0291 17.00 0.0290

o-0437 “5.55 o-0437 0.0583 34.00 0.0582 0.0745 43.57 0.0745

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

TABLE VII

FERROUS AMMONlUhI SULPHATE -- ------ --_ -_----.------------- _. -- _ _ _____

FeSO,. (NH,),S0,.6H,O o.roooZV Chloramine-B used FeSO,. (NH,),SOI. 6H,O taken found

6 ml 6 -_-.--________ _______._____ ____ ._

0.2352 6.00 0.2351

0.3920 9.97 0.3907 0.5880 14.95 0.58Go 0.7056 IS.00 o.7o55 o.g408 ‘3.95 o-9387

___ ._____ --._-_- --__--.-_-_ -_- _. ._._ -----__ I___-

TABLE VIII

HYURAZINE SULPHATE ~-~-- ---_- --__ _-..- -- _... -_ _ -_-

N,H,H,SO, taken 0.1020N Chloramine-B used NzHdI-I,S04 found g ml 6

-_-------- __ ___.__ __.-.. __-..-_-___ _- __._ --. ._--- -__- 0.0325 9.80 0.032G

o*o553 I G-75 o.o555 0.0813 24.60 0.0815 0.1105 33.43 0.1107 0.14G3 44.25 0.1465

-___- ..__ ---_-

I:. SINGIf, li. C. SOCll~

C,)r,I(c)I-l), t~ll<cll 0. J oo,YN Chlornminc-13 usctl C,H.,(OH), found 6 ml 6’

‘I’lic I-csitlts sl10w tht tllc: substances given in ‘l’ablcs I to IS c;in 1112 cletcrlnii~d clii;tntitalivd_y by tlw iodine nwnocllloriclc mctliocl, using chloraminc-1.2 :LS oxidizing agcllt.

Clllurun~mc-U 11;~s bcc~i uwcl :ic: an usiclizllig agalt ill hvtlroclilo~rc acid medium lor tllc volutnet.rJc cstirnntloiis of potnssii~rn icxlitlc, arsciiikiis osidc, Cxrtxr-cmcatic, nicrcuroils cliloritle, st;~nxioiis chloricle, l)c)t;tssi~~rn thJocyail;~tc, ferrous ~~mmoniuni siilphatc, hyclrnziuc sulpliatc :ind l~ydroqiiiiloiic, using iorlInc m0tl0clllorJdC! iIS ;l

~i~ti~lyst ;~Jicl prc-osirlixcr. Clilorr~fOrm is uwil ;is ii~i intlJc,ltor. It is colourctl p~nlc owing to i_lic libcrution of ioclluc clurinl: the titration ;~iitl lxxo~i~os l&lit p~lc ~cllow at Lhc clitl-puint Ixcnusc of tl~c lorii~at~on 0f ioclinc inunochloridc.

IA cl~lOradJlc- IJ pcut istrc 1ltilisGc commc osytlzmt en solution clllorhydriquo, pour lc clos~~~c volumbtriquc clcs compos& sulvants: iutlurc clc potnssiuJn, nnliyclridc ars6nicus, GxnGtiquc, clilorurc dc mcrcurc(I), chlorurc cl’btnin(lI), thiocyanatc de potasuillm, sulfate clc fcr(II) ct cl’ntn~nollium, sulfate cl’hydrnzlnc et hydroquinone. On utilisc ponr ccttc cl~tcrmiii:~tion lc monoclllorurc tl’iotlc commc catalyscur et prGosycln11t, ct Ic cliloroformc ~0ii~nir iiiclicxteur. Cc rlcriiicr se colorc en violet par l’ioclc lib&(? lxxid~~nt iii titration ct rlevlent jaliiic pC~lc i~u point final par formation clc n~onocliIorure tl’ioclc.

1Da.s Clilor;imin-I.3 lcnnn in salzsaurcr Ltsung nls Osyclationsmittcl vcrwcndet wcrclcn fGr clic volumetriscl~e 13cstimmun~ folgencler Vcrbinclungcn: I<aliumjoclicl, arsenigc Siiurc, Nnt;riuJn-IC~~liumtartrnt, ~~!uecl~silbcr(I)chloricl, Zinn(II)chloricl, l~nliumrliorl~u~id, l~iScll(lI)-i~.mm0~liunlsulf~~t. Hyclrazinsulfnt nnd Hyclrochinon. litir clicsc 13estimmnng vcrwcnclct man Joclmonocliloricl nls liatdysator uncl voroxy- clicrcndes Mittcl uncl clns Chloroform als Inclikntor. IDieses lctztc fhrbt sic11 violctt tlurcll das wiihrcnd clcr Titrntlon frci ~cworclcnc Joel uncl wircl dnnn scl~wnc1~ pAb bcim Enclpunlcte; clics clurch 131lclun~ voll Joclmonochlor~cl.

Rcceivccl March r stli, i 95-1