Question

Name the gas evolved in each of the following cases:
(i) Copper carbonate is heated strongly.
(ii) Action of dilute hydrochloric acid on sodium sulphite.
(iii) Nitrogen combines with hydrogen.
(iv) Action of dilute sulphuric acid on sodium carbonate.
(v) Addition of sodium to cold water.

Answer 1

(i) When green copper carbonate {${CuCO}_3$} is heated it decomposes forming copper oxide {$CuO$} and carbon dioxide {${CO}_2$}.

(ii) when hydrochloric acid reacts with sodium sulphite, it forms sodium chloride and sulphur dioxide which gives smell of burning sulphur.

(iii) When hydrogen gas combines with nitrogen to form Ammonia the following chemical reaction will take place.

$N_2+{3H}_2\to {2NH}_3$

(iv) when dilute sulphuric acid reacts with sodium carbonate, carbon dioxide gas is evolved.

$H_2{SO}_4+{Na}_2{CO}_3\to {Na}_2{SO}_4+H_{2}O+{CO}_2$

(v) Sodium element is a very reactive metal. If a small amount of sodium is thrown in water, it usually wizzes on top reacting vigorously to form Sodium Hydroxide and Hydrogen gas.