Write the formulae of the salts given below.

Potassium sulphate, sodium sulphate, calcium sulphate, magnesium sulphate, copper sulphate, sodium chloride, sodium nitrate, sodium carbonate and ammonium chloride.

Select from the following group of these salts which may be dissolved in water to make it hard.

(I) Sodium chloride
(II) Sodium sulphate
(III) Calcium chloride
(IV) Calcium sulphate
(V) Potassium chloride
(VI) Magnesium sulphate

Write the balanced chemical equations of the following reactions.

(a) Sodium hydroxide + sulphuric acid $\to$ sodium sulphate + water

(b) Potassium bicarbonate + sulphuric acid $\to$ potassium sulphate + carbon dioxide + water

(c) Iron + sulphuric acid $\to$ ferrous sulphate + hydrogen.

(d) Chlorine + sulphur dioxide + water $\to$ sulphuric acid + hydrogen chloride

(e) Silver nitrate $\to$ silver + nitrogen dioxide + oxygen

(f) Copper + nitric acid $\to$ copper nitrate + nitric oxide + water

(g) Ammonia + oxygen $\to$ nitric oxide + water

(h) Barium chloride + sulphuric acid $\to$ barium sulphate + hydrochloric acid

(i) Zinc sulphide + oxygen $\to$ zinc oxide + sulphur dioxide

(j) Aluminium carbide + water $\to$ aluminium hydroxide + methane

(k) Iron pyrites ($Fe{S}_2$) + oxygen $\to$ ferric oxide + sulphur dioxide

(l) Potassium permanganate + hydrochloric acid $\to$ potassium chloride + manganese chloride + chlorine + water

(m) Aluminium sulphate + sodium hydroxide $\to$ sodium sulphate + sodium meta aluminate + water.

(n) Aluminium + sodium hydroxide + water $\to$ sodium meta aluminate + hydrogen

(o) Potassium dichromate + sulphuric acid $\to$ potassium chloride + chromium chloride + water + chlorine.

(p) Sulphur + nitric acid $\to$ sulphuric acid + nitrogen dioxide + water.

(q) Sodium chloride + manganese dioxide + sulphuric acid $\to$ sodium hydrogen sulphate + manganese sulphate + water + chlorine.