What are colligative properties ?

Explanation

The vapour pressure of solution decreases when a non - volatile solute is added to a volatile solvent. There are many properties of solutions which are connected with this decrease of vapour pressure. These are :
(i) Relative lowering of vapour pressure of the solvent.
(ii) Depression of freezing point of the solvent.
(iii) Elevation of boiling point of the solvent and
(iv) Osmotic pressure of the solution.
All these properties depend on the number of solute particles irrespective of their nature relative to the total number of particles present in the solution. Such proiperties are called colligative properties.