Nitrogen and hydrogen combine in the presence of a catalyst to give ammonia gas. With reference to the above reaction:

(a) Name the catalyst used.

(b) At what temperature does the above reaction occur?

(c) What optimum pressure should be maintained during the reaction?

1 mole of CO₂ occupies 24 dm³ at room temperature and pressure. Calculate the following:

(a) The mass of 6 litres of CO₂.

(b) The volume occupied by 60 g of CO₂.

[Atomic weight: C=12, O=16]

Define:

(a) Electrolyte

(b) Catenation

Name the most appropriate method of preparation of the following salts:

(a) Copper carbonate

(b) Sodium sulphate

(c) Ferric chloride