At 473 K , equilibrium constant , K_(c), for the decomposition of phosphorous pentachloride, PCl_(5) " is " 8*3 xx 10^(-3). If decomposition is depicted as: PCl_(5) (g) hArr PCl_(3) (g) + Cl_(2) (g) , Delta_(r) H^(@) = 124*0 " kj mol"^(-1) (a) Which an expression forK_(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 (i0 mor " PCl_(5) is added (ii) pressure is increases (iii) temperature is increased ?

At 473 K , equilibrium constant , K_(c), for the decomposition of phos

1.	At 473 K , equilibrium constant , K_(c), for the decomposition of phosphorous pentachloride, PCl_(5) " is " 83 xx 10^(-3). If decomposition is depicted as: PCl_(5) (g) hArr PCl_(3) (g) + Cl_(2) (g) , Delta_(r) H^(@) = 1240 " kj mol"^(-1) (a) Which an expression forK_(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 (i0 mor " PCl_(5) is added (ii) pressure is increases (iii) temperature is increased ?
Answer» Solution :(a) ` K_(c) = ([PCl_(3)(g) ] [Cl_(2)(g)] )/([PCl_(5)(g)])` (b)`K'1/K_(c) = 1/(83 xx 10^(-3))=12048` ©(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 increasewith increase of temperature .