The vapour pressure of two liquids P and Q are 100 and 50 torr, respectively. The total vapour pressure of solution obtained by mixing 3 moles of P and 2 moles of Q would be

Options

A. 140 torr
B. 20 torr
C. 68 torr
D. 80 torr

Answer

D

Explanation

`"Mole fraction of "P=(3)/(3+2)=(3)/(5)`
`"Mole fraction of "Q=(2)/(3+2)=(2)/(5)`
Hence, total vapour pressure
`="mole fraction of "PxxV.P.of P+" mole fraction of "QxxV.P.of Q`
`(3)/(5)xx100+(2)/(5)xx50=80"torr"`