# Why don't covalent compounds dissociate in water?

I understand that ionic compounds dissociate when dissolved in water. Why don't covalent compounds do the same?

• Some of them do. For example, $\ce{HCl}$ that is absolutely covalent in gas phase almost completely dissociates in diluted solutions. – permeakra Aug 22 '16 at 4:27

In the case of HCL, the polar water molecules can solvate making $\ce{H3O^+_{aq} and Cl^-_{aq}}$ where both ions are surrounded by a few water molecules. Water has a very high dielectric constant (relative permittivity) which means that electric fields are 'damped', i.e they are attenuated to short range so that oppositely charged ions can easily separate and hence exist independently in solution.