Question

A mixture of phenol and aniline shows negative deviation from Raoult's law. This is due to the formation of:

• A. Polar covalent bond
• B. Non-polar covalent bond
• C. ntermolecular Hydrogen bond
• D. Intramolecular Hydrogen bond

Answer 1

The Correct Option is C

• A negative deviation from Raoult's law occurs when the vapor pressure of a solution is lower than expected. This happens when the intermolecular forces between the components of the solution are stronger than the forces between the molecules of the individual components in their pure states.
• In the case of a mixture of phenol and aniline, the two compounds can form intermolecular hydrogen bonds between the hydroxyl group of phenol and the amine group of aniline. These strong interactions reduce the vapor pressure of the solution compared to what is predicted by Raoult's law.

Thus, the negative deviation is caused by the formation of intermolecular hydrogen bonds, making option (C) the correct answer.

Answer 2

Phenol and aniline form intermolecular hydrogen bonds between the hydroxyl group of phenol and the amino group of aniline. These interactions cause a negative deviation from Raoult’s law because the actual vapour pressure of the mixture is lower than expected for ideal solutions.