Which one of the following liquid pairs will exhibit a positive deviation from Raoult’s law

Options

(a) n-hexane and n-heptane
(b) Ethanol and chloroform
(c) Phenol and aniline
(d) Chloroform and acetone

Correct Answer:

Ethanol and chloroform

Explanation:

Since attractive forces between ethanol and chloroform will be weaker as compared to ethanol-ethanol and chloroform-chloroform, hence the tendency to escape is more and vapour pressure of solution is higher than the pure components resulting in positive deviation from Raoult’s law.