Sodium hydroxide solution is added first in a small quantity, then in excess to the aqueous salt solutions of copper [II] sulphate, zinc nitrate, lead nitrate, calcium chloride and iron [III] sulphate. For each of the aqueous salt solutions, state - a] the colour of the precipitate when NaOH is added in a small quantity,b] the nature of precipitate [i.e. soluble or insoluble, when NaOH is added in excess.