The Students' Guide in Quantitative Analysis - Free Ebooks Library

QUANTITATIVE ANALYSIS,
Jpirate for some time, and then pour the content, ol the
Stleinto a beaker, rinse with water, and add snfhuent
HCl to decompose the K.Mn.O,. Filter the colorless so-
lution. add BaCl. to throw dow^i the H,bO„ and proceed
as usual.
3 Method employed by J. Lowthian Bell.
Dissolve in HCl as above, and pass the gases through a
solution of potassic pUunbate (lead nitrate super-saturated
with KHO), Boil half an hour, or until the evolution of
gas has ceased. Wash the PbS formed, oxidize it with
IINOj, and throw down the S as BaSO^ by means of
Ba(NOj),. Let stand 24 hours, collect on a filter, dry,
ignite, and weigh. This method is said to give higher
p^ercentages of S than that of Eggertz. Compare Fres.,
I
218, 3-
4. Method of Arthur H. Elliott. See Am. Client.,
Vol. I, page 376.
5. Method emfbyed by Y^om^cK 2siA Dietz. See Prac-
tical Manual oi Chemical Analysis and Assaying applied
to Iron, Translated by Robert Mallet. London, 1872.
Dissolve 3 to 5 grms. borings in HCl in a flask connected
with four bottles, the first a condenser, the three following
containing solution of AgNOj( I
part of nitrate to 20 parta
of water). Boil, and when gas ceases to evolve, aspirate.
Pour contents of flask on one filter, and wash the Ag^S,
Wash out the flask and cleanse the ends of the tubes wltn
bromine water, and expel excess of Br by heat ; the follow-
ing reaction ensues
:
Ag.S+8Br+4H,0=H,SO,+2AgBr+6HBr.
The phosphide is also converged into phosphoric acti
Filter from AgBr. and ppt. H,SO, with BaCi, as U5uai.