What is relative lowering of vapour pressure?
Vapour pressure is the pressure exerted by the vapours over the liquid under the equilibrium conditions at a given temperature. Now let us take an example of a pure liquid, the surface of the liquid is occupied by the molecules of the liquid. Suppose a non-volatile solute is now added to this pure liquid. Since the solute molecules are non-volatile, the vapour above the solution consists of only solvent (pure liquid) molecules. After adding the solute, the vapour pressure of the solution is found to be lower than that of the pure liquid at a given temperature.it is called relative lowering of Vapour pressure
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