`PCl_(5)(g) ltimplies PCl_(3)(g) +Cl_(2)(g)`
`{:(प्रारंभिक मोल ,x,0,0),(साम्य पर मोल ,0.05,x-0.05,x-0.05):}`
`K_( C) = ([PCl_(3)][Cl_(2)])/([PCl_(5)])`
`8.3 xx 10^(-3) = ((x-0.05) xx (x-0.05))/(0.05)`
`(x-0.05)^(2) = 8.3 xx 10^(-3) xx 0.05`
`=4.15 xx 10^(-4)`
`x-0.05 = sqrt(4.15 xx 10^(-4)) = 2.037 xx 10^(-3) = 0.02`
`therefore x=0.05 + 0.02 = 0.07`
`therefore [PCl_(3)]=[Cl_(2)]=x-0.05`
`=0.07 - 0.05=0.02`