How does enthalpy affect solubility?
Decreasing the energy required to separate the solute particles and increasing the energy of solvation of the particles will increase the solubility if a substance.
The solution process involves three steps.
- Separation of solvent particles;
- Separation of solute particles,
- Solvation of solute particles,
That is, solution will occur if the enthalpy of solvation is more negative than the sum of the enthalpies of separation.
This is important when ionic and polar substances are involved.
When nonpolar substances are involved, the enthalpy changes are small. In those cases, entropy changes become important factors.