Sodium hydroxide solution is added first in a small amount, then in excess to the aqueous salt solutions of:
1. copper [II] sulphate
2. zinc nitrate
3. lead nitrate
4. iron [III] sulphate
State in each case :
(i) the colour of the precipitate when NaOH is added in a small quantity;
(ii) the nature of the precipitate [i.e. soluble or insoluble] when NaOH is added in excess.

(i) The colour of the precipitate when NaOH is added in a small quantity are as follows —

1. Pale blue — copper [II] sulphate
2. White — zinc nitrate
3. Chalky white — lead nitrate
4. Reddish brown — iron [III] sulphate

(ii) the nature of the precipitate [i.e. soluble or insoluble] when NaOH is added in excess are as follows —

1. Insoluble — copper [II] sulphate
2. Soluble — zinc nitrate
3. Soluble — lead nitrate
4. Insoluble — iron [III] sulphate