Q.

At 25oC the vapour pressure of benzene, C6H6 (78 g/mole), is 93.2 Torr and that of toluene, C7H8 (92 g/mol), is 28.2 torr. A solution of 1.0 mole of C6H6 and 1.0 mol of C7H8 is prepared. Calculate the mole fraction of C6H6 in the vapour above this solution (assume the solution is ideal).