A substance dissolves if the attraction between the particles of the solute and the solvent is enough to overcome the attraction of the particles of each substance for the others of the same type. The attraction between ions in table salt and water molecules is enough to pull both individual ions away from the salt crystal and to separate the water molecules to accommodate the ions. Napthalene does not dissolve in water because napthalene does not exert a strong enough attraction to water molecules to separate them and make room for itself. Temperature also affects solubility differently depending on the solute.
Why do some things dissolve in water and others don’t?
