An ideal equimolar binary liquid solution of A and B has a vapour pressure of 900 mm of Hg. It is distilled at a constant temperature till (2)/(3) (i.e 66.67 % ) of the original amount. If themole fraction of A is 0.3 in residue and that of B in condensate 0.4 and also the vapour pressure of residue is 860 mm Hg which of the following is correct ?

An ideal equimolar binary liquid solution of A and B has a vapour pres

1.	An ideal equimolar binary liquid solution of A and B has a vapour pressure of 900 mm of Hg. It is distilled at a constant temperature till (2)/(3) (i.e 66.67 % ) of the original amount. If themole fraction of A is 0.3 in residue and that of B in condensate 0.4 and also the vapour pressure of residue is 860 mm Hg which of the following is correct ?
Answer» Mole fraction of A is more than that of B in vapour phase, above residue as well as above condensate. Vapour pressure of condensate is more than `900 mm Hg` at same temperature. In vapour pressure of residue, vapours of A are more contributing. If the solution WOULD be DISTILLED till `50%` of the original amount then mole fraction of B in liquid condensate would be more than that of A in same solution. Solution :Using Rault's law `P_(A)^(@) = 1000 mm Hg` and `P_(B)^(0) = 800 mm Hg` As 'A' is more volatile, hence (A) and (D) are incorrect. In CASE of 'C' `P_(A) = 0.3 xx 1000 = 300 mm Hg`,