At `25^(@)C`, the total pressure of an ideal solution obtained by mixing 3 mole of A and 2 mole of B, is 184 torr. What is the vapour pressure (in torr) of pure B at the same temperature (Vapour pressure of pure A at `25^(@)C` is 200 torr) ?

Options

A. 180
B. 160
C. 16
D. 100

Answer

B

Explanation

`p=p_(A)^(@)((n_(A))/(n_(A)+n_(B)))+p(n_(B)/(n_(A)+n_(B)))`
`184=200((3)/(3+2))+p_(B)^(@)((2)/(3+2))`
`184=200xx(3)/(5)+p_(B)^(@)xx(2)/(5)`
`184=120+p_(B)^(@)(2)/(5)`
`rArr64=p_(B)^(@)(2)/(5)`
`p_(B)^(@)=(64xx5)/(2)=160"torr"`