Question

(a) Name a metal for each case:
(i) It does not react with cold as well as hot water but reacts with steam.
(ii) It does not react with any physical state of water?
(b) When calcium metal is added to water, the gas evolved does not catch fire but the same gas evolved on adding sodium metal to water catches fire. Why is it so?

Answer 1

(a) (i) Aluminium does not react with cold or hot water but it reacts with steam.
(ii) Gold does not react with any physical state of water.

(b) Sodium is more reactive than calcium. The reaction between sodium and water produces a large amount of heat, which causes the evolved hydrogen to burn and catch fire. But in the reaction between calcium and water, no heat is produced and hence the evolved hydrogen does not catch fire.