Benzene and toluene form nearly ideal solution. At `20^(@)C` the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at `20^(@)C` for a solution containing 78g of benzene and 46 g of toluene in torr is-

Options

A. 50
B. 25
C. `37.5`
D. `53.5`

Answer

A

Explanation

`P_(B)=p_(B)^(@)X_(B), therefore P_(B)=((78)/(78))/((78)/(78)+(46)/(92))xx75, therefore P_(B)=50` torr