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QJEEM24Chea57: JEE Main 2024 Chemistry - Class 12 JEEM24Chea57 Solution: A solution of two miscible liquids showing negative deviation…
A solution of two miscible liquids showing negative deviation from Raoult's law will have :
Multiple Choice Options
- A increased vapour pressure, increased boiling point
- B increased vapour pressure, decreased boiling point
- C decreased vapour pressure, decreased boiling point
- D decreased vapour pressure, increased boiling point
Step-by-Step Verified Solution
Negative Deviation from Raoult's Law
Effect on Vapor Pressure and Boiling Point
Answer
- Negative deviation means the intermolecular forces of attraction between the molecules of the two liquids (A-B) are stronger than the forces between molecules of the pure liquids (A-A and B-B).
- This stronger attraction makes it harder for molecules to escape into the vapor phase.
Effect on Vapor Pressure and Boiling Point
- Vapor Pressure : Since the molecules are held more tightly, the vapor pressure of the solution will be lower than expected from Raoult's law. Decreased vapor pressure.
- Boiling Point : A lower vapor pressure means you need to increase the temperature further to reach atmospheric pressure, where boiling occurs. Therefore, the boiling point of the solution will be higher than expected. Increased boiling point.
Answer
The correct answer is Option D: decreased vapor pressure, increased boiling point.