The Students' Guide in Quantitative Analysis - Free Ebooks Library

QyWtllTlTATIVE ANALYSIS.
^^f, I _Somc of tho till may go into solution as
litratc of titi, H' tli*-^ "'^^'^^ '^^'^^ '^"^ '^'^^''^^' ^"^^ ^'^"^ ^J^^''''^''
in Precipitate c mixed witli tlie sulphide of antimony ; in
this case they should be separated by F. W. Clarke's
method which is based on the solubility of the sulphide
of tin in oxalic acid, and details of which may he found in
Crookcs' Sckcl Methods, page 249- I'O!- another method
sec Fres., § 165. 4. «- ^l^o § £65, 7, a-
On the other hand, some of the antimony
Note ->. —
and lead may refuse to dissolve and remain with Residue a,
in which case proceed as follows :
after igniting and weigh-
ing tlic SnO, + Pl> ? + Sb ? fnse with Na,C03 and sulphur
in a porcelain crucible. Dissolve in warm water and filter
from the residue of PbS, which may be treated with HNOj
in a porcelain crucible and wci:j,hed as PbSO,. To the
alkaline solution add sliglit excess of HCl and collect
precipitate of SbSj + SnS, + S on filter; dry and remove
excess of S by washing with CS„ transfer to porcelain
capsule, oxidi/x with UNO, evaporate to dryness, fuse
with NallO in a .silver dish, dissolve the mass in a mixture
uf three volumes of alcohol and one of water, and filter
from the antimoniatc of sodium. For details, see Fres.,
§ 165, 4, a To the solution containing stannatc of sodium,
add UCl, saturate with ILS, and treat the precipitated
SnSj as usual. See Fres., § 126, I, c, and § 9E.
Consult article on the Estimation of Antimony, by E.
M. Bartlcy, in American Chemist, Vol. V, page 436; also
paper by Dr. Clemens Winkler, in Fresenius' Zcitschrift
fur Analj'tischc Ckemic, Heft 2, 1875.