Question

What happens to the vapour pressure when a) volatile solute dissolves in the liquid b) the dissolved solute is non volatile

Answer 1

Vapour pressure depends on
· Nature of liquid
· Temperature
· Presence of impurities

A non volatile solute particle lowers the vapour pressure of solvent because solute particles become surrounded by solvent particles when dissolved. This causes the particles of solvent to evaporate less because it requires more energy for the particles to do this since the solvent to solute attraction are strong. So the vapour pressure of a solution is less than that of the pure solvent.

when a volatile solute is added then more vapours are formed hence more pressure is exerted by the vapours on the solution