Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
-----------------
sulphur : S8
sodium sulfide : Na2S . 3H2O
sodium hydroxide : NaOH
antimony sesquioxide : Sb2O3
Class:
------
elem=Sb
coordination
precipitation
Summary:
--------
Antimony sesquioxide does not dissolve in a concentrated solution of NaOH
nor does it react with sulfide or one of the polysulfides in strongly
alkaline environments.
Description:
------------
Add some Sb2O3 to a fairly concentrated solution of NaOH: The solid does not
appear to dissolve. If part of it dissolves, then it is only a small part.
Prepare a polysulfide/sulfide solution by adding some sulphur to a warm
solution of sodium sulfide and add this yellow/brown liquid to the liquid,
containing the dissolved NaOH and the solid Sb2O3: No visible reaction.
When the liquids are mixed and the resulting mixture is allowed to settle,
then a white solid separates out of a yellow liquid. Finally there is a
clear yellow liquid with a white solid on the bottom of the test tube.