The effect of temperature on solubility is governed by Le Chatelier's Principle.

• For a majority of solid solutes, the dissolution process is endothermic (Heat is absorbed; $\Delta H_{soln}>0$).
• Increasing the temperature provides energy to the system, causing the equilibrium to shift in the forward direction (more dissolving) to consume the excess heat.
• Therefore, solubility generally increases with an increase in temperature for such substances. Pressure has negligible effect on the solubility of solids.