1. This is caused by dissociation in the case of KCl and association in the case of acetic acid. KCl in aqueous solution undergoes dissociation as KCl → K+ + Cl-
Molecules of ethanoic acid (acetic acid) dimerises in benzene due to hydrogen bonding.
As a result of dimerisation the actual number of solute particles in solution is decreased. As colligative property decreases molecular mass increases.
2.
