Question

Sir please explain how vapor pressure of solution increases due to decreased concentration

Answer 1

Vapour pressure increases with decrease in concentration of solute or in other words the concentration of the solute increases, the vapor pressure of the solvent decreases

Vapour pressure of a liquid at any temperature can be defined as the pressure exerted by the vapours of the liquid in equilibrium with the liquid itself. The vapour pressure of a pure solvent decreases /lowers when a non- volatile solute is added(concentration of solute increases) to the solvent. This is because, on adding the solute, some of the solute molecules also occupy the surface hence the number of the solvent molecules present on the surface would decrease as compared to pure solvent. Since the number of solvent molecule on the surface is decreases it will decrease the number of evaporating molecules on surface which results in lowering of vapour pressure.

I hope now it is clear that how vapour pressure inversely changes with concentration of solute