Vapour pressure of a solvent is the pressure exterted by vapour when they are in equilibrium with it
Channel: Doubtnut
Date: 02/08/2020

Vapour pressure of a solvent is the pressure exterted by vapour when they are in equilibrium with its solvent at that temperature. The vapour pressure of solvent is dependent of nature of solvent, temperature, addition of non-volatile solute as well as nature of solute to dissociate or associate. The vapour pressure of a mixture obtained by mixing two valatile liquids is given by `P_(M) = P_(A)^(@).X_(A)+P_(B)^(@).X_(B)` where `P_(A)^(@)` and `P_(B)^(@)` are vapour pressures of pure components `A` and `B` and `X_(A), X_(B)` are their mole fractions in  mixture. For solute-solvent system, the relatio becomes `P_(M) = P_(A)^(@).X_(A)` where `B` is non-volatile solute.    The vapour pressure at `102^(@)C` of a non-electrolytic solution having `b.pt.  375 K` is: