QJEEAdv16Ch07c2: JEE Advanced 2016 Chemistry - Class 12 JEEAdv16Ch07c2 Solution: Mixture (s) showing positive deviation from Raoult’s law at 35…
Multiple Choice Options
- A carbon tetrachloride + methanol
- B carbon disulphide + acetone
- C benzene + toluene
- D phenol + aniline
Step-by-Step Verified Solution
When intermolecular attraction between two components A and B in the mixture is same as between A and A or B and B, hence it is a case of ideal solution. When intermolecular attraction between A and B in a mixture is smaller than that between A and A or B and B, then mixture is more vaporised, bp is lowered. It is a case of positive deviation from Raoult’s law. When intermolecular attraction between A and B is higher than that between A and A or B and B, then mixture is less vaporised, bp is increased. It is a case of negative deviation.
(a) Methanol molecules (CH)3OH are hydrogen bonded. In a mixture of CCl4 and CH3OH, extent of H-bonding is decreased. Mixture is more vaporised thus, positive deviation from Raoult’s law.
(b) Acetone molecules have higher intermolecular attraction due to dipole-dipole interaction. With CS2 , this interaction is decreased thus, positive deviation.
(c) Mixture of benzene and toluene forms ideal solution.
(d) Phenol and aniline have higher interaction due to intermolecular H-bonding. Hence, negative deviation.