At `473 K`, equilibrium constant `K_(c )` for decomposition of phosphorus pentachloride, `PCl_(5)` is `8.3xx10^(-3)`. If decomposition is depicted as,
`PCl_(5)(g) hArr PCl_(3)(g)+Cl_(2)(g) Delta_(r)H^(Θ)=124.0 kJ mol^(-1)`
a. Write an expression for `K_(c )` for the reaction.
b. What is the value of `K_(c )` for the reverse reaction at the same temperature?
c. What would be the effect on `K_(c )` if
i. More `PCl_(5)` is added
ii. Pressure is increased
iii. The temperature is increased?

Explanation

(a) ` K_(c) = ([PCl_(3) (g) ] [Cl_(2)(g)] )/([PCl_(5)(g)])`
(b)`K'1/K_(c) = 1/(8*3 xx 10^(-3))=120*48`
© (i) No effect as `K_(c) ` is constant temperature .
(ii) No effect
(iii) As given reaction is endothermic , on increasing the temperature , ` k_(f)` will increase . As ` K_(c) = (k_(f))/(k_(b)) ,`
`K_(c)` will increase with increase of temperature .