1) Add a few drops of acidified potassium manganate(VII) solution to solution A.

2) Add a few drops of acidified potassium dichromate(VI) solution to solution A.

3a) Add a few drops of iron(III) chloride solution acidified with dilute hydrochloric acid to solution A.
Stir gently for a few minutes and observe.

3b) Add a few drops of sodium hydroxide solution to the mixture in (a).

4) Add a few drops of iodine solution to solution A.

5a)Add a portion of B add an equal volume of copper(II) sulphate and leave to stand for a few minutes.

b) Add aqueous sodium thiosulphate to the mixture from (a), until no further change.

6) Add acidified hydrogen peroxide solution to 2 cm³ of solution B.

7) Add a spatula of C to 1 cm3 of concentrated hydrochloric acid in a test tube. Warm gently.
Test the gas evolved with damp blue litmus paper.