Question

Phenol dimerises in benzene having van’t Hoff factor 0.54. Its degree of association is:

• A. 0.54
• B. 0.46
• C. 0.92
• D. 0.27

Hint:

Van’t Hoff factor helps determine the extent of association or dissociation in solutions, affecting colligative properties like osmotic pressure and boiling point elevation.

Answer 1

The Correct Option is C

Phenol molecules in benzene tend to associate as dimers through hydrogen bonding, reducing the number of effective particles in solution. The degree of association ($\alpha$) can be calculated using the van’t Hoff factor equation. Since dimerization reduces the number of particles, the van’t Hoff factor is lower than 1, leading to a degree of association of 0.92.