Question

A sample of pure `PCl_(5)` was introduced into an evacuted vessel at `473 K`. After equilibrium was attained,concentration of `PCl_(5)` was found to be `0.5xx10^(-1)mol litre^(-1)`. If value of `K_(c)` is `8.3xx10^(-3) mol litre^(-1)`. What are the concentrations of `PCl_(3)` and `Cl_(2)` at equilibrium ?

Answer 1

`PCl_(5)(g) hArr PCl_(3)(g)+Cl_(2)(g)`
`{:(At,0.5xx10^(-1),,x mol L^(-1),x mol L^(-1)),("Equilibrium","mol" L^(-1),,,("suppose")):}`
`:. K_(c )=x^(2)/(0.5xx10^(-1))=8.3xx10^(-3)` (Given)
or `x^(2)=(8.3xx10^(-3))(0.5xx10^(-1))=4.15xx10^(-4)`
or `x=sqrt(4.15xx10^(-4))=2.04xx10^(-2) M=0.02M`