Question

Assertion: The mixing of two completely miscible liquids A and B showing positive deviation from Raoult’s law is followed by an absorption of heat.

Reason: The A-A molecular interaction forces are stronger than the A-A or B-B molecular interaction forces.

Options

• If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion.

• If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.

• If Assertion is CORRECT but Reason is INCORRECT.

• If Assertion is INCORRECT but Reason is CORRECT.

Answer 1

If Assertion is CORRECT but Reason is INCORRECT.

Explanation:

Liquids showing positive deviation from Raoult’s law absorb heat on mixing because the A-B intermolecular forces are weaker than those in the pure liquids (A-A and B-B). This weak interaction leads to less stability and thus endothermic mixing. However, the reason given is incorrect because it wrongly compares A-A forces to themselves, making the statement illogical.