what element explodes in water?

The element that explodes in water is sodium (Na).

The element that explosively reacts with water is sodium (Na). When sodium reacts with water, it produces sodium hydroxide (NaOH) and hydrogen gas (H2). This reaction is highly exothermic and can result in an explosion. It is important to note that this reaction should not be attempted without proper safety precautions as it can be dangerous.