What is the mole ration of benzene `(P_(B)^(@)`=150 torr) and toluene `(P_(T)^(@)` =50 torr) in vapour phase if the given solution has a vapour pressure of 120 torr?

Options

A. `7:1`
B. `7:3`
C. `8:1`
D. `7:8`

Answer

A

Explanation

`P = p_(B) .x^(o)x_(B) +p_(r ) .x_(f)`
`120 = 150 (x_(B)) +50 (1-x_(B))`
`100 xx x_(B) = 70 `
`x_(B) = 0.7`
`Y_(B) = (x_(B)p_(B)^(o))/P = (0.7 xx150)/120 = 0.875`
`Y_(r ) = 1- 0.875 = 0.125 `
`(Y_(B))/(Y_(r ))=7/1 `