Convert — (a) nitrogen to ammonia (b) hydrogen to hydrogen chloride – by a direct combination reaction.

Give balanced equations for thermal decomposition of :

(a) lead carbonate

(b) lead nitrate

(c) ammonium dichromate

(d) mercury [II] oxide

(e) calcium hydroxide

Define a displacement reaction with example. State why Zn displaces H₂ from dil. H₂SO₄ but Cu does not.

Explain the term double decomposition precipitation reaction. Give a balanced equation for the preparation of two different insoluble lead salts from their salt solutions by double decomposition precipitation.