Question

In a solvent S, a compound B is partially dissociated into C and D as given below:
B \(\rightleftharpoons\) 2C + 2D
B, C and D are non-volatile in nature. The molar mass of B is 10 times the molar mass of S. The standard boiling point and the standard enthalpy of vaporization of S are 400 K and 10R J mol\(^{-1}\), respectively (R is the gas constant in J K\(^{-1}\) mol\(^{-1}\)). A solution of B in S with an initial concentration of B as 0.25% (mass/mass) has a boiling point of 408 K at 1 bar pressure. In this solution, the mole percent of B that has been dissociated is _______.

Hint:

For dissociation reactions, first determine the van’t Hoff factor using the total number of particles formed after dissociation, then use colligative property equations.

Answer 1

Correct Answer: 33.3