The correct option for the values of vapour pressure of a solution at `45^@C` with benzene to octane in molar ration 3:2 is:
[At `45^@C` vapour pressure of benzene is 280mm Hg and that of octane is 420mm Hg, Assume ideal gas]

Options

A. 168 mm of Hg
B. 336 mm of Hg
C. 350 mm of Hg
D. 160 mm of Hg

Answer

B

Explanation

Given : `n_(C_(6)H_(6)):n_(C_(8)H_(18))=3:2`
So, `chi_(C_(6)H_(6))=(3)/(5),chi_(C_(8)H_(18))=(2)/(5)`
`P_(S)=P_(C_(6)H_(6))^(0)chi_(C_(6)H_(6))+P_(C_(8)H_(18))^(0)chi_(C_(8)H_(18))`
`=280xx(3)/(5)+420xx(2)/(5)`
`=168+168`
= 336 mm of Hg.