Question

Name the gas evolved in each of the following cases
(i) Action of heat on blue vitriol
(ii) Nitrogen dioxide gas is passed through potassium iodide solution
(iii) Action of heat on mercuric oxide.
(iv) Addition of dilute hydrochloric acid to baking soda
(v) Addition of caustic soda to ammonium sulphate

Answer 1

(i) H2O

(ii) I2

(iii) O2

(iv) CO2

(v) NH3

Explanation:

(i) Water Vapour - When blue vitriol is heated, the water of crystallization escape out of the crystal and leave behind anhydrous copper sulphate.

(ii) Iodine - Nitrogen dioxide gas is passed through potassium iodide solution to liberate iodine.

(iii) Oxygen - Mercury (II) oxide decomposes when heated to produce mercury and oxygen gas.

(iv) Carbon dioxide - Mixing baking soda with hydrochloric acid results in table salt, as well as water and carbon dioxide.

(v) Ammonia - Ammonium sulphate reacts with sodium hydroxide to produce water, ammonia and sodium chloride.