Colligative Properties

Concept: When a solution and pure solvent are separated by a semipermeable membrane, solvent molecules naturally move from the solvent side to the solution side. This process is called osmosis.
Definition: The minimum pressure that must be applied to a solution to just stop the flow of solvent through a semipermeable membrane is called osmotic pressure.
Explanation:
Solvent flows from lower solute concentration to higher solute concentration.
Applying external pressure on the solution side can stop this flow.
The required pressure to stop osmosis is called osmotic pressure.

where,
= osmotic pressure
= molar concentration
= gas constant
= temperature