Question

‘The osmotic pressure measured when benzoic acid is dissolved in benzene is less than the expected value’. Comment.

Answer 1

1. The osmotic pressure calculated for benzoic acid in benzene shows an abnormal value due to association of benzoic acid by forming H-bonds, thereby resulting into a dimer.
2. As colligative properties depend on number of particles and mass of each particle,this situation will show variation in practicality.
3. Due to association of benzoic acid molecules,the effective number of particles will be halved and mass of one particle will be doubled from theoretical data.