What is Konowaloffs Rule ?
Konowaloffs Rule states that in case of ideal solutions or solutions showing small positive or negative deviations, at any fixed temperature, the vapour phase is always richer in the more volatile component as compared to the solution phase. In other words, the mole fraction of the more volatile component is always greater in the vapour phase than in the solution phase. Konowaloffs Rule is very useful in the separation of binary liquid solution by distillation.
The mole fraction of benzene in vapour phase is (0.77) more than that in liquid phase (0.5) but the mole fraction of toluene in the vapour phase (0.23) is less than that in liquid phase (0.5). This is because benzene is more volatile than toluene.
