SOLUBILITY

Solubility of a substance expresses the maximum amount of it which can be dissolved in a specific amount of solvent.

The solubility of a substance depends on 

1. the nature of solute (like dissolves like)
2. nature of solvent
3. temperature
4. pressure.

Solubility of a solid in a liquid

When a solute is added to the solvent, some solute dissolved and its concentration increases in solution. This process is known as dissolution. Some solute particles in solution collide with the solid solute particles and get precipitated. This process is known as crystallisation. After some time a stage reached when both the rates dissolution and crystallisation become same and this stage is termed as dynamic equilibrium.

Saturated solution: The solution in which no more solute can be dissolved is known as saturated solution. This happens when the dynamic equilibrium reached.

The saturated solution can be made unsaturated by either adding more solvent or by increasing temperature.

Effect of temperature on solubility of solid in liquids: Generally the process of dissolution can be considered as endothermic process (enthalpy change is +ve) and the solubility being dynamic equilibrium process must follow Le-Chateliers Principle. According to the principle the being endothermic process the solubility should incease with rise in temperature and vice-versa for the exothermic process.

Effect of pressure- Solids and liquids are highly incompressible therefore pressure has no effect on solubility of solids in liquids.

For better explanation reder to the following video

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