Benzene (C6H6, 78 g/mol) and toluene (C7H8, 92 g/mol) form an ideal solution. At 60oC the vapour pressure of pure benzene and pure toluene are 0.507 atm and 0.184, respectively. The mole fraction of benzene in a solution of these two chemicals that has a vapour pressure of 0.350 atm at 60oC