`AB_(3)(g)` is dissociation as `AB_(2)(g) hArr AB_(2)(g)+(1)/(2)B_(2)(g)`,
When the initial pressure of `AB_(2)` is 800 torr and
the total pressure developed at equilibrium is 900 torr.
What fraction of `AB_(3)(g)` is dissociated ?

Options

A. 0.1
B. 0.2
C. 0.25
D. 0.3

Answer

C

Explanation

`AB_(3(g)) Leftrightarrow AB_(2(g))+1/2 B_(2(g))`
At equilibrium `800-x" x "x/2`
`800-x+x+x/2 =900 rArr x=200`
% dissociated `=(200)/(800) xx 100=25`
`[PCl_(3)]=1.2 xx 10^(-3) mol L^(-)`
`[Cl_(2)]=1.2 xx 10^(-3) mol L^(-1)`