Question

Give reasons for the following :

(a) Hydrogen can be used as a fuel.

(b) Though hydrogen is lighter than air it cannot be collected by downward displacement of air.

(c) A pop sound is produced when hydrogen gas is burnt.

(d) Helium has replaced hydrogen in weather observation balloons.

(e) Nitric acid is not used for the preparation of hydrogen gas.

Answer 1

(a) Coal gas, water gas and liquid hydrogen are some signi cant fuel.
(b) Since hydrogen is lighter than air. it is possible to collect the gas by downward displacement of air.
But it is not safe to do so since a mixture of hydrogen and air can lead to an explosion.
(c) Impure hydrogen gas bums in air with a pop sound. This is because of the presence of impurities in it.
(d) If there is small leakage of hydrogen in a balloon, it forms a mixture with air that can explode. So helium has replaced hydrogen.
(e) Hydrogen cannot be prepared by the action of nitric acid on metals because it also releases nitrous oxide and nitric oxide and oxides the hydrogen to form water.