Potassium iodide solution could be identified by its reaction with iron(III) sulfate solution.
This is a redox reaction where
Omitting the spectator ions:
Addition of starch solution would give a blue/black precipitate to confirm the presence of iodine since iron(III) and iodine are both brown in colour.
Barium chloride solution would give a white precipitate with iron(III) sulfate solution of barium sulfate. Again, omitting the spectators:
Strictly speaking you should add an XS of dilute HCl to dissolve other possible precipitates.
If you mix iron(III) sulfate solution with the
Aluminium will dissolve in warm sodium hydroxide solution to give sodium aluminate and hydrogen:
This reflects the amphoteric nature of aluminium.
The same type of reaction occurs with zinc which is also amphoteric:
If ammonium ions are warmed with hydroxide ions, ammonia gas is evolved which will turn red litmus blue:
An aqueous solution of chlorine will react with sodium hydroxide solution, removing any green colouration due to elemental chlorine:
This is an example of "disproportionation". Chlorine (0) is simultaneously oxidised to
It is quite spectacular and is known as "The Volcano Experiment".
This reacts with water:
Green chromium(III) oxide is also amphoteric and will dissolve in aqueous alkali to give
Under these conditions hydrogen peroxide is a powerful oxidising agent and is able to oxidise green