`PCl_(5)` is `10%` dissociated at `1 atm`. What is `%` dissociation at 4 atm . `PCl_(5)(g)hArr PCl_(3)(g)+Cl_(2)(g)`

Explanation

Degree of dissociation `alpha=0.40`
But `alpha=(D-d)/(d(n-1))`
`PH_(3(g)) Leftrightarrow 1/4 P_(4 (g))+3/2 H_(2(g))`
`n=1/4+3/2=(1+6)/(4)=7/4 =1.75`
Vapour density of pure `PH_(3)=(34)/(2)=17`
0.40=`(17-D)/(d(1.75-1))=(17-d)/(0.75d)`
`0.75xx0.40d=17-d`
`1.3d=17" d=17/1.3=13.076"`