At 473 K, equilibrium constant, Kc for decomposition of phosphorus pentachloride, PCl5 is 8.3 × 10-3. If decomposition is depicted as: PCl5(g) leftharpoons PCl3(g) +Cl2(g) ; ΔrH°=124.0 kJ mol-1 what would be the effect on reaction if the temperature is increased?

Question

At 473 K, equilibrium constant, Kc for decomposition of phosphorus pentachloride, PCl5 is 8.3 × 10-3. If decomposition is depicted as: PCl5(g) leftharpoons PCl3(g) +Cl2(g) ; ΔrH°=124.0 kJ mol-1 what would be the effect on reaction if the temperature is increased? (A) Reaction will shift in the backward direction (B) Reaction will shift in the forward direction (C) Reaction is in equilibrium (D) Reaction first moves forward and then remains at equilibrium

Tardigrade Admin · Accepted Answer

Kc=([PCl3(g)][Cl2(g)]/[PCl5(g)]) As the reaction is endothermic, the increase in temperature will favour the forward reaction. More PCl5 will dissociate to form PCl3 and Cl2.

Q. At 473K, equilibrium constant, Kc​ for decomposition of phosphorus pentachloride, PCl5​ is 8.3×10−3. If decomposition is depicted as : PCl5(g)​⇌PCl3(g)​+Cl2(g)​ ; Δr​H∘=124.0kJmol−1 what would be the effect on reaction if the temperature is increased?

Reaction will shift in the backward direction

Reaction will shift in the forward direction

Reaction is in equilibrium

Reaction first moves forward and then remains at equilibrium

Kc​=[PCl5(g)​][PCl3(g)​][Cl2(g)​]​ As the reaction is endothermic, the increase in temperature will favour the forward reaction. More PCl5​ will dissociate to form PCl3​ and Cl2​.

$K_{c} = \frac{[ PC l _{3 (g)} ] [ C l _{2 (g)} ]}{[ PC l _{5 (g)} ]}$
As the reaction is endothermic, the increase in temperature will favour the forward reaction. More $PC l_{5}$ will dissociate to form $PC l_{3}$ and $C l_{2}$ .