The vapour pressures of pure liquids A and B are 400 and 600 mmHg, respectively at 298 K on
mixing the two liquids, the sum of their initial volume is equal ot the volume of the final mixture.
The mole fraction of liquid B is 0.5 in the mixture, The vapour pressure of the final solution, the
mole fractions of components A and B in vapour phase, respectively are :