At 300K, the vapour pressure of an ideal solution containing 3 mole of A and 2 mole of B is 600 torr. At the same temperature, if 1.5 mole of A & 0.5 mole of C (non-volatile) are added to this solution the vapour pressure of solution increased by 30 torr. What is the value of `"P"_("B')^(@)`?

Options

A. 940
B. 405
C. 90
D. None of these

Answer

C

Explanation

`600=3/5"P"_("A")^(0)+2/5"P"_("B")^(0)………….("I")`
`630=4.5/7"P"_("A")^(0)+2/7"P"_("B")^(0).............("ii")`
Solving equation (i)& (ii)`" P"_("B")^(0)=90`