A binary liquid mixture of acetone and chloroform shows negative deviation from Raoult's law. Which of the following statements are correct?

AThe observed partial pressure of each component is lower than the value predicted by Raoult's law
B $Δ_{mix} V > 0$ for the mixing process
CThe mixture forms a minimum-boiling azeotrope
D $Δ_{mix} H < 0$ for the mixing process

Answer: A, D

Negative deviation arises when A-B attractions (here hydrogen bonding between chloroform and acetone) exceed A-A and B-B attractions. Heat is released (

Δ_{mix} H < 0

) and volume shrinks (

Δ_{mix} V < 0

), and each partial pressure is lower than

x_{i} p_{i}^{0}

. The vapour pressure is lowered, so the boiling point rises and a maximum-boiling azeotrope forms, not a minimum-boiling one.

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A binary liquid mixture of acetone and chloroform shows negative deviation from Raoult's law. Which of the following statements are correct?

Answer: A, D

More questions on Raoult's law, ideal and non-ideal solutions, azeotropes