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) When sodium metal is dropped in water, hydrogen gas in liberated. Due to extreme heat released as the reaction is exothermic, {{H}_{2}} gas catches fire.
2Na + 2${{H}{2}}O ------>2NaOH + {{H}{2}}
(ii) When sodium metal is heated in free supply of air or oxygen, it burns forming sodium peroxide and some super oxide (Na{{O)}{2}})
<img src="/uploads/db3785/original/2X/0/04af98c306debee3636d74182e4256951fa5202c.png" width="245" height="62">
(iii) When sodium peroxide is dissolved in water, it gives {{H}{2}}$${{O}_{2}}$
