An Ionic Solid Dissolving in Water

When an ionic substance or highly polar compound dissolves in water, water molecules orient themselves around the ions or polar compound, hydrating the species. In the solution process the hydration that occurs around the ion or polar compound involves ion-dipole or dipole-dipole bond fomation. While these interactions are weak, they are strong enough that the solution process is generally accomplished with a gain (endothermic) or loss (exothermic) of energy. The details of the parameters which govern the energy of the solution process involve a knowledge of the solute-solute attractive forces, the solvent-solvent attractive forces and the solute-solvent attractive forces.