When sodium (Na) is mixed with water (H₂O), a chemical reaction occurs, producing sodium hydroxide (NaOH) and hydrogen gas (H₂) .

Here's the chemical equation:

2 Na + 2 H₂O → 2 NaOH + H₂

This reaction is highly exothermic, meaning it releases a lot of heat. The heat can ignite the hydrogen gas, causing a small explosion.