Question
At 473K, equilibrium constant Kc for decomposition of phosphorus pentachloride, PCl5 is 8·3 × 10–3. If decomposition is depicted as
(a) write an expression for Kc for the reaction.
(b) what is the value of Kc for the reverse reaction at the same temperature?
(c) what would be the effect on Kc if:
(i) more PCl5 is added
(ii) pressure is increased
(iii) temperature is increased?
Solution
(b) Kc for reverse reaction
(c)
(i) Kc remains unchanged when more PCl5 is added.
(ii) When pressure is increased, Kc remains unchanged.
(iii) As given reaction is endothermic, on increasing the temperature, Af will increase.
As 
will increase with the increase of temperature.
