Question

Why does the solubility of a solute (like table salt) increase with increasing temperature of the solution?

Answer 1

Funnily enough, the dissolution of NaCl is fairly insensitive to increased temperature, but in general higher temperatures result in greater ionic solubilities.

Explanation:

Dissolution of a salt in water is a bond breaking reaction. For salts, this involves the breaking of strong ionic bonds between the counterions and the formation of aquated ions, which we represent as `Na^+(aq)`, i.e. `Na(OH_2)_6^(+)`, for example. Since this is a bond-breaking reaction, dissolution of ionic salts should indeed be enhanced at higher temperatures, in that the higher temperatures allow disruption of ion-ion bonds. Likewise, dissolution of non-ionic solutes should be greater at higher temperature, as solute-solute interactions still have to be overcome.