Question

Does sodium explode in air?

Answer 1

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

$$\begin{gathered} 4\mathrm{Na}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{Na}}_2\mathrm{O}\left(\mathrm{s}\right) \\ (\mathrm{sodium}\mathrm{oxide}) \\ 2{\mathrm{Na}}_2\mathrm{O}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{Na}}_2{\mathrm{O}}_2\left(\mathrm{s}\right) \end{gathered}$$

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

$$\begin{gathered} {\mathrm{Na}}_2\mathrm{O}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2\mathrm{NaOH}\left(\mathrm{aq}\right) \\ (\mathrm{sodium}\mathrm{oxide})(\mathrm{sodium}\mathrm{hydroxide}) \end{gathered}$$

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

$$\begin{gathered} 2\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)\to {\mathrm{Na}}_2{\mathrm{CO}}_3\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ (\mathrm{sodium}\mathrm{hydroxide})(\mathrm{sodium}\mathrm{carbonate}) \end{gathered}$$

Sodium is a highly reactive metal that reacts strongly with the air's oxygen, carbon dioxide and humidity so that it can also spark a burn.

Sodium is kept immersed in kerosene to avoid this explosive reaction since sodium does not react with kerosene.