(a) What are non-ideal solutions?
(b) What role does the molecular interaction play in deciding the vapour pressure of solutions (i) alcohol and acetone (ii) chloroform and acetone?

Explanation

(a) Non-ideal solutions are those solutions which
(i) do not follow Raoult's law (ii) `DeltaH_("mix")!=0`. (iii) `DeltaV_("mix")!=0`.
(iv) The force of attraction between `A-A` and `B-B` is not equal to `A-B`.
(b) (i) In alcohol and acetone, force of attraction is less than in alcohol and alcohol molecules as well as in acetone and acetone molecules therefore, vapour pressure increases.
(ii) In chloroform and acetone, force of attraction increases due to intermolecular `H-`bonding therefore, vapour pressure decreases.