Osmotic Pressure (p)
The osmotic pressure of a solution at a particular temperature may be defined as the excess hydrostatic pressure that builds up when the solution is separated from the solvent by a semi-permeable membrane. It is denoted by p.
Osmotic pressure may be defined as the excess pressure which must be applied to a solution in order to prevent flow of solvent into the solution through the semi-permeable membrane.
Osmotic pressure is the excess pressure which must be applied to a given solution in order to increase its vapour pressure until it becomes equal to that of the solution.
Measurements of osmotic pressure : Following methods are used for the measurement of osmotic pressure,
(a) Pfeffer’s method,
(b) Morse and Frazer’s method,
(c) Berkeley and Hartley’s method,
(d) Townsend’s negative pressure method,
(e) De Vries plasmolytic method.