CBSE
Class 10 Class 12
It can be defined as the given amount of substance (called the solute) that dissolves in a given amount of a liquid substance (Called the solvent).
It depends on various factors:
1) Nature of solute
2) Nature of solvent
3) Temperature
4) Pressure
Solubility is the physical quantity of solution.
Many gases dissolve in water. For example, oxygen dissolves in water at very small extent. Hydrogen chloride gas (HCl) is highly soluble in water.
The solubility of gases in liquid affected by pressure and temperature.
Affect of temperature:
Increase in temperature reduces the solubility of gases in liquids.Increased temperature causes an increase in kinetic energy. The higher kinetic energy causes more motion in the gas molecules which break intermolecular bonds and escape from solution.
Affect of pressure:
The solubility of gases increases with the increase of pressure.
The law states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas.
It also states that the partial pressure (p) of a gas in the vapour phase is proportional to the mole fraction of the gas(x) in the solution.i.e.,
P = KHX
KH is Henry's law constant.
Application of Henry's law in industry.
Every solid does not dissolve in the given liquid. The solubility depends on the intermolecular interactions of solutes and solvents.
solubility follows like dissolves like principle. For example, sodium chloride and sugar readily dissolve in water whereas, naphthalene and anthracene do not.
On the other hand, naphthalene and anthracene dissolve readily in benzene but sodium chloride and sugar do not.
It is observed that polar solutes dissolve in polar solvents and non-polar solutes in non-polar solvents.
When a solid solute is added to the solvent, some solute dissolves and its concentration increases in solution. This process is known as dissolution.
Saturated Solution: A solution in which no more solute can be dissolved in the solvent at the same temperature and pressure is known as a saturated solution.
Effect of temperature:
The solubility of a solid in a liquid is affected by temperature changes.According to Le Chateliers Principle in a saturated solution, if the dissolution process is endothermic (Δsol H > 0), the solubility should increase with rise in temperature but if the dissolution process is exothermic (Δsol H > 0) the solubility should decrease.
Effect of pressure:
Pressure does not have any effect on the solubility of solids in liquids. It is so because solids and liquids are highly incompressible and practically remain unaffected by changes in pressure.
