State why sulphuric acid was called – 'oil of vitriol'.

State how you would convert (i) sulphur (ii) chlorine (iii) sulphur dioxide — to sulphuric acid.

In the Contact process

(i) State how you would convert (a) sulphur (b) iron pyrites to sulphur dioxide in the first step of the Contact process.

(ii) State the conditions i.e. catalyst, promoter, temperature and pressure in the catalytic oxidation of sulphur dioxide to sulphur trioxide in the Contact tower. Give a balanced equation for the same.

(iii) State why the above catalytic oxidation reaction supplies energy.

(iv) Give a reason why – vanadium pentoxide is preferred to platinum during the catalytic oxidation of sulphur dioxide.

(v) Give a reason why the catalyst mass is heated electrically – only initially.

(vi) State why sulphur trioxide vapours are absorbed in concentrated sulphuric acid and not in water to obtain sulphuric acid.

Give a reason why concentrated sulphuric acid is kept in air tight bottles.