Q34 / 180 · COMEDK 2018 · Chemistry

Osmotic pressure observed when benzoic acid is dissolved in benzene is less than that expected from theoretical considerations. This is because

A
benzoic acid is an organic solute
B
benzoic acid has higher molar mass than benzene
Correct answer
C
benzoic acid gets associated in benzene
D
benzoic acid gets dissociated in benzene

Solution

Osmotic pressure is a colligative property. It depends upon the number of solute particles. Benzoic acid undergoes dimerisation. $\therefore$ Number of particles reduces $(i < 1)$ Hence, osmotic pressure observed is less than the theoretical consideration.

Hence, the correct answer is option: 'C'.

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