Here's why:

* Ionic compounds are made up of positively charged ions (cations) and negatively charged ions (anions) held together by electrostatic forces.

* Water is a polar solvent, meaning it has a positive and negative end due to the uneven sharing of electrons in the molecule.

* When an ionic compound is placed in water, the positive ends of water molecules surround the negative ions (anions) and the negative ends of water molecules surround the positive ions (cations).

* This interaction weakens the electrostatic forces holding the ions together, causing them to separate and become surrounded by water molecules.

This process is called dissociation, and it's a crucial step in many chemical reactions and biological processes.