Osmotic pressure

Osmotic pressure is the minimum pressurewhich needs to be applied to a solution to prevent the inward flow of its pure solventacross a semipermeable membrane.^[1] It is also defined as the measure of the tendency of a solution to take in pure solvent (which belongs to the solution under discussion) by osmosis. Potential osmotic pressure is the maximum osmotic pressure that could develop in a solution if it were separated from its pure solvent by a selectively permeable membrane. The phenomenon of osmosisarises from the propensity of a pure solvent to move through a semipermeable membrane and into its solution containing a solute to which the membrane is impermeable. This process is of vital importance in biology as the cell's membrane is semipermeable.

Application 

Osmotic pressure is an important factor affecting cells. Osmoregulation is the homeostasis mechanism of an organism to reach balance in osmotic pressure.

• Hypertonicity is the presence of a solution that causes cells to shrink.
• Hypotonicity is the presence of a solution that causes cells to swell.
• Isotonicity is the presence of a solution that produces no change in cell volume.