ANHYDROUS STANNIC CHLORIDE 27362V HC1 — in warm Na2S. Does the mosaic gold dissolve in
these reagents? Can you explain the difference?
- Write ionized equations for (a) the precipitation of basic
stannous chloride SnOHCl, when a solution of SnCl 2 is diluted
with a large amount of water; (6) the conversion of SnOHCl to
SnS when this precipitate is treated with Na 2 S solution.
PKEPABATION 44
ANHYDROUS STANNIC CHLORIDE, SnCl 4
Anhydrous stannic chloride, SnCU, is prepared by the action
of dry chlorine gas upon metallic tin. It is a colorless, very
mobile liquid which boils at 114°. At ordinary temperature it
has a considerable vapor pressure, and the vapor, reacting strongly
with the water vapor of the air, gives rise to dense fumes. With
liquid water stannic chloride reacts violently. If a limited amount
of water is added with caution it is possible to obtain solid hydrates
of the composition SnCl4-3H 2 O, or SnClr5H 2 O. These hydrates
dissolve to form apparently clear solutions, but the salt is very
extensively hydrolyzed, the rather complex hydrolysis products
remaining for the most part in a colloidal condition.
Materials: feathered tin, 119 grams = 1 F.W.
chlorine (from a cylinder or generated from granu-
lar MnO 2 and 122V HC1).
tin foil.
Apparatus: 350-cc. tubulated retort or distilling flask.
five 8-ounce wide-mouth bottles.
chlorine generator (2,000-cc. flask) or cylinder of
liquid chlorine.
36-inch condenser.
250-cc. distilling flask.
150-cc. container for stannic chloride: the neck
must be previously drawn out to a narrow tube
that can be quickly sealed off in blast flame.
delivery tubes, connectors, and rubber stoppers as
in diagram.
tripod.
2 ring stands.
2 iron rings.
clamp and fastener.
2 Bunsen burners.