Question

Sodium peroxide forms a white compound when it comes into contact with moist air. Explain.

Answer 1

Sodium reacts with the oxygen in air to form sodium oxide, and traces of yellowish sodium peroxide.

4Na+O2→2Na2O4Na+O2→2Na2O

2Na2O+O2→2Na2O22Na2O+O2→2Na2O2

The sodium oxide formed will react with water to give sodium hydroxide.

Na2O+H2O→2NaOHNa2O+H2O→2NaOH

The sodium hydroxide formed will react with carbon dioxide to give sodium carbonate, which is relatively unreactive to the atmosphere, barring the hygroscopicity.

2NaOH+CO2→Na2CO3+H2O2NaOH+CO2→Na2CO3+H2O

Note: I’m still a bit doubtful about the reaction of sodium metal with atmospheric water directly. Probably, the reaction with atmospheric oxygen will be faster, because I have never seen sodium metal turning whitish on exposure, though it does lose its lustre and and reactivity (just the surface).

PS: I work with sodium…the observations are true.

Answer 2

HEY MATE HERE'S YOUR ANSWER;

Sodium peroxide (Na2O2) hydrolyzes to give sodium hydroxide (NaOH) and hydrogen peroxide(H2O2) when it is treated with water according to the reaction-

Na2O2 + 2H2O -> 2NaOH + H2O2

The reaction is highly exothermic as Na2O2 reacts violently with water.

Hope it helps!