The vapour pressures of A and B at 25 ° C are 90 mmHg and 15 mm Hg respectively. If A and B are mixed such that the mole fraction of A in the mixture is 0 . 6 , then the mole fraction of B in the vapour phase is x × 10 - 1 . The value of x is (Nearest integer)

Step-by-step solution

Given P A ° = 90   mmHg , at 25 ° C P B = ∘ 15   mmHg and X A = 0 . 6 X B = 0 . 4 P T = X A P A o + X B P B o = ( 0 . 6 × 90 ) + ( 0 . 4 × 15 ) = 54 + 6 = 60   mm Now mol fraction of B in the vapour phase i.e. Y B = P B P T = X B P B o 60 = 0 . 1 = 1 × 10 - 1 therefore: x = 1