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