62 K
= 241 98 g mol–1
Thus, experimental molar mass of benzoic acid in benzene is
= 241 98 g mol–1
Now consider the following equilibrium for the acid:
2 C6H5COOH  ⇌   (C6H5COOH)2
If x represents the degree of association of the solute then we would
have (1 – x ) mol of benzoic acid left in unassociated form and
correspondingly 2
x  as associated moles of benzoic acid at equilibrium Therefore, total number of moles of particles at equilibrium is:
1
1
2
2




x
x
x
Thus, total number of moles of particles at equilibrium equals van’t Hoff
factor i