Two liquids P and Q have vapour pressures 450 and 200 torr respectively at certain temperature. In an ideal solution of the two, the mole fraction of P at which two liquids have equal partial pressures is.

Options

A. `0.80`
B. `0.308`
C. `0.444`
D. `0.154`

Answer

B

Explanation

Let the mole fraction of P be x .
Mole fraction of `Q = 1 -x`
`450 x = 200 (1-x)`
`650 x = 200`
` x = (200)/(650) = 0.308`