The Students' Guide in Quantitative Analysis - Free Ebooks Library

QUANTITATIVE ANALYSIS.
;a«on no longer gives a blue mark on the KI starch paper.
Repeat on fresh amount Cautioi: Shake, and draw off
turbid liquid,
{iL) Cakulation.
Amoimt taken
[French chlorimctrical degrees represent the number of
jitrcs o£ CI at o.^C. and 760 m.ra., which one kil. of sample
should yield. Now one litre of CI weighs 3,177 grms.;
hence 31.77 per cent. = 100 degrees. Sec foot-note on
p. 700 of Fres. Qumi. Anal]
The amount of ca/dum chloride present may be de-
termined by first estimating the hypochlorite as above, and
then adding to the second portion of 50 c.c. a slight excess
of NHJ-10 and warming.
3 CaClA + 4 NH, = 3CaCl, + 6H,0 + 4N,
Neutralize the solution with HNOj and determine the
CI by AgNOj.
The amount of chlorate may be determined by heating
a third portion with ammonia, then acidulation with pure
H,S04 and digesting with Zn.
Ca(ClOj). + 12H = CaCl, {- 6H,0.
Again determine the CI by AgNOj, and the increased
amount over the second determination gives tjic 01 exist-
ing as chlorate. (Thorpe.)