State your observations when dilute hydrochloric acid is added to :

(i) Lead nitrate soln. and the mixture is heated.

(ii) Copper carbonate.

(iii) Sodium thiosulphate.

Identify the gas evolved and give the chemical test in each of the following cases.

Dilute hydrochloric acid reacts with:

(i) Iron [II] sulphide.

(ii) Sodium sulphite.

Identify the substance underlined – A solid formed by the reaction of two gases, one of which is acidic and the other basic in nature.

State one relevant observation – Action of dilute hydrochloric acid on iron [II] sulphide.