What happens when
a. Sodium metal is dropped in water?
b. Sodium metal is heated in free supply of air?
c. Sodium peroxide dissolves in water?

Explanation

(i) When Na metal is dropped in water It reacts violently to form sodium hydroxide and hydrogen gas. The chemical equation involved in the reaction is:
`2Na_((s))+2H_(2)O_((l)) rarr 2NaOH_((aq))+H_(2(g))`
(ii) On being heated in air, sodium reacts virorously wiht oxygen to form sodiu peroxide the chemical equation involved in the reaction is:
`2Na_((s))+O_(2(s))rarr Na_(2)O_(2(s))`
(iii) When sodium peroxide is dissolved in water it is readily hydrolysed to form sodium hydroxide and water. The chemical equation involved in the reaction is:
`Na_(2)O_(2(s))+2H_(2)O_((l)) rarr 2NaOH_((aq))+H_(2)O_(2(aq))`