Here's why:

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

* Water is a polar molecule, meaning it has a slightly positive end and a slightly negative end.

* When an ionic compound is added to water, the water molecules surround the ions and pull them apart, breaking the electrostatic forces holding the compound together.

* The separated ions are then surrounded by water molecules, forming a hydrated ion.

* Hydrated ions are too small to scatter visible light, resulting in a clear solution.

Important Note: While many ionic compounds form clear solutions, there are exceptions. Some ionic compounds may be colored due to the presence of transition metal ions, and some may form cloudy or even precipitate out of solution depending on their solubility.