During the reaction of some metals with dilute hydrochloric acid, following observations were made.
(a) Silver metal does not show any change
(b) The temperature of the reaction mixture raises when aluminium is added.
(c) The reaction of sodium metal is found to be highly explosive.
(d) Some bubbles of a gas are seen when lead reacts with the acid.
Explain these observations giving suitable reasons.

Explanation

(a) Silver is less reactive than hydrogen.
(b) The reaction is exothermic.
(c) Sodium is highly reactive.
(d) Lead, more reactive than hydrogen , reacts with HCl and displaces hydrogen from its solution.