(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 wth 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?

Explanation

(a). (i) Iron (ii) Copper
(b). More heat is evolved during the reaction of sodium metal with water due to which the hydrogen gas formed catches fire. On the other hand, less heat is evolved during the reaction of calcium metal with water which cannot make the hydrogen gas burn.