Here's why:

* Ionic compound: Sodium oxide is an ionic compound, meaning it's formed by the electrostatic attraction between positively charged sodium ions (Na+) and negatively charged oxide ions (O²⁻).

* Water's polarity: Water (H₂O) is a polar molecule, meaning it has a slightly positive end (hydrogen) and a slightly negative end (oxygen). This polarity allows water to interact strongly with ions.

* Dissolution: When sodium oxide is added to water, the polar water molecules surround the sodium and oxide ions, breaking the ionic bonds holding them together in the solid. The ions become hydrated (surrounded by water molecules) and disperse throughout the solution.

Reaction with water:

The dissolution of sodium oxide in water is an exothermic reaction, meaning it releases heat. It forms a solution of sodium hydroxide (NaOH):

Na₂O (s) + H₂O (l) → 2 NaOH (aq)

Important note: The reaction between sodium oxide and water is quite vigorous, producing a lot of heat. It's important to handle sodium oxide with caution.