The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K . What is the composition of the liquid mixture if total vapour pressure is 600 mm Hg.

0.3,0.7 0.5, 0.5 0.4, 0.6 0.2, 0.8

0.4, 0.6

P=P0AXA + P0BXB 600=450x + 700(1-x) 600=450x + 700 - 700x 600-700=-250x -100=-250x x=0.4 1-x=0.6