To 50 mL of water, a few mL of acetone is mixed. The vapour pressure of water above the solution becomes

Options

A. equal to the vapour pressure of the solution
B. equal to the vapour pressure of the pure water
C. less than the vapour pressure of the pure water
D. more than the vapour pressure of the pure water.

Answer

C

Explanation

The solution shows negative deviation because of the formation of H - bond between acetone and water.

H-bonding between acetone and water
Alternatively, `P_A/(P_A^@) = X_A , " In solution " X_A lt 1`
`:. P_A lt P_A^@`