A liquid mixture containing two immiscible liquids, wate and an alkyl bromide `("molar mass 137 g mol"^(-1))` is distilled at `90^@C.` The ratio of the vapour pressure of water and alkyl bromide in the distillate is 5:1, the mass ratio of distillate is : a)1.52 : 1 b)0.657 : 1 c)1 : 5 d)5 : 1

Options

A. `1.52:1`
B. `0.657:1`
C. `1:5`
D. `5:1`

Answer

B

Explanation

`P._(H_(2)O) = P_(M) xx X_(H_(2)O)`
`P._(AD)= P_(M) xx X_(AB)`
`therefore (P._(H_(2)O))/(P._(AB)) = (n_(H_(2)O))/(n_(AB)) = (w_(H_(2)O) xx m_(AB))/(m_(H_(2)O) xx w_(AB))`
`(5)/(1) = (w_(H_(2)O) xx 137)/(w_(AB) xx 18) or (w_(H_(2)O))/(w_(AB)) = (5 xx 18)/(1xx 137)= (90)/(137)= 0.657:1`