A solution of two miscible liquids showing negative deviation from Raoult's law will have :

Solution

Chemistry ma’am · 4 steps

Negative deviation: A and B cling together, so fewer molecules escape and boiling needs more heat.

1. Stronger mixed attractions. In a negative deviation, the A–B attractions in the mixture are stronger than the A–A and B–B attractions in the pure liquids. A classic case is chloroform and acetone, which hydrogen bond with each other.
2. Vapour pressure falls. Molecules held more tightly escape less easily into the vapour. So the vapour pressure is lower than Raoult's law predicts.

   pₜₒₜₐₗ < x_A p_A° + x_B p_B°

3. Boiling point rises. A liquid boils when its vapour pressure reaches the outside pressure. A lower vapour pressure needs a higher temperature to get there, so the boiling point increases.
4. So. The solution has decreased vapour pressure and increased boiling point, which is option (d).

The idea to keep. Vapour pressure and boiling point always move in opposite directions. Negative deviation means lower vapour pressure and higher boiling point; positive deviation means the reverse.

Answer from the NTA final answer key. Solution by PrepWiser.