(i) $\mathrm{H}_2$ gas is evolved which catches fire due to the heat generated during the reaction. 2Na + $2\mathrm{H}_2\mathrm{O}$ → $2\mathrm{NaOH}+\mathrm{H}_{2(g)}$ ↑ (ii) Sodium peroxide is formed along with a small amount of $\mathrm{Na}_2\mathrm{O}$ $2\mathrm{Na}_{(s)} + \mathrm{O}_{2(g)}$ → $\underset{\text{(minor)}}{2\mathrm{Na}_2\mathrm{O}_{(s)}}$ $\mathrm{Na}_2\mathrm{O}_{(s)} + \frac{1}{2}\mathrm{O}_2$ → $\underset{\text{(major)}}{\mathrm{Na}_2\mathrm{O}_{2(s)}}$ (iii) It liberates hydrogen peroxide. $\mathrm{Na}_2\mathrm{O}_2+2\mathrm{H}_2\mathrm{O}$ → $2\mathrm{NaOH} + \mathrm{H}_2\mathrm{O}_2$