If two substances A and B have `p_(A)^(@): p_(B)^(@) = 1:2` and have mole fraction in solution as 1:2 then mole fraction of A in vapour phase is

Options

A. 0.33
B. 0.25
C. 0.52
D. 0.2

Answer

D

Explanation

`{:("In solution, if ", x_(A)x",",x_(B)=2x),("and if",p_(A)^(@)=p",",p_(B)^(@)=2p),(therefore,p_(A)=x xxp",",p_(B)=2x xx 2p=4x xxp),(therefore, p_("total")=5 x p.,):}`
Mole fraction in vapour phase
`(y_(A))=(p_(A))/(P_("total"))=(xp)/(5xp)=(1)/(5)=0.2`