A binary liquid mixture shows negative deviation from Raoult's law. For the mixing process, which pair of signs is correct?

Answer: C

Negative deviation means A-B attractions are stronger than A-A and B-B attractions. Mixing therefore releases heat (

Δ H_{mi x} < 0

) and the molecules pack more closely (

Δ V_{mi x} < 0

). Both ideal behaviour (zero) and positive deviation (both positive) are excluded.

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