Write two differences between a solution showing positive deviation and a solution showing negative deviation from Raoult’s law.
Positive deviations:
(i) A ─ A interactions are stronger than A ─ B interactions, thus higher repulsive forces and hence a & B excape easily from the solution.
(ii) Dissolution of such components is endothermic in naure
(iii) Mixing volume is more than the original theoritcal total volume ΔVmix≥ 0
(iv) Vapour pressure of the solution is higher than the individual components due to easy escape of volatile components.
(v) E.g. water-kerosene, acetone-benzene,etc.
Negative deviations:
(i) A ─ B interactions are stronger than A ─ A interactions, thus the attractive forces are stronger and cannot be excape easily.
(ii) Heat is releases on dissolution.
(iii) Mixing volume is less than the total volume of individual components, ΔVmix≤ 0
(iv) Individual component vapour pressure is higher than solution.
(v) E.g. acetone-aniline, chloroform-benzene.