Name an alloy of:

(a) Aluminium used in aircraft construction

(b) Lead, used in electrical circuits in joining metals.

(c) Copper, in electrical appliances or household vessels.

(a) State why ethyne burns in oxygen with a sooty flame?

(b) Write the balanced chemical equation when water is added to calcium carbide.

Give the balanced chemical equations for the following reactions:

(a) Potassium sulphate from potassium hydroxide and sulphuric acid.

(b) Barium sulphate from barium chloride and sodium sulphate.

(c) Copper sulphate from copper and concentrated sulphuric acid.

State one relevant observation for each of the following.

(a) Dilute hydrochloric acid is added to sodium thiosulphate.

(b) Mixture of ammonium chloride and sodium hydroxide is heated.

(c) Burning of ammonia in air.