A liquid mixture shows positive deviation from Raoult's law. The intermolecular A-B interactions in this solution are:
Aabsent in the mixed solution
Bstronger than A-A and B-B interactions
Cweaker than A-A and B-B interactions
Dexactly equal to A-A and B-B interactions
Answer & Solution
Correct answer: C. weaker than A-A and B-B interactions
1. Positive deviation means observed vapour pressure is higher than Raoult's law predicts.
2. This happens when A-B attractions are weaker than A-A and B-B attractions.
3. Molecules then escape more easily, raising vapour pressure (e.g. ethanol-acetone).
_Source: NCERT Class 12 Chemistry Ch 1 "Solutions", p.12_
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