What happens when
(i) sodium metal is dropped in water? (ii) sodium metal is heated in free supply of air?
(iii) sodium peroxide dissolves in water?
(i) ${ H }_{ 2 }$ gas is evolved which catches fire due to the liberation of extreme heat in the reaction.
2 Na (s) + 2 $H { 2 }O$(l) -------> 2NaOH (aq) + ${ H }{ 2 }$(g)
(ii) $Na _{ 2 }$$O _{ 2 }$ along with a small amount of $Na _{ 2 }O$ is formed.
4 Na (s) + 02 (g) ------ > 2 $Na _{ 2 }O$ (s)
$Na _{ 2 }O$ (s) +1/2 $O _{ 2 }$ ------- > $Na _{ 2 }$$O _{ 2 }$ (s)
(iii) $H _{ 2 }$$O _{ 2 }$ is formed when sodium peroxide is dissolved in water.
$Na _{ 2 }$$O _{ 2 }$ (s) + 2 $H _{ 2 }O$ (l) ------- > 2 NaOH (aq) + $H _{ 2 }$$O _{ 2 }$(l)