Question

If some $He$ gas is introduced into the equilibrium ${PCl}_{5\left(g\right)}\rightleftharpoons {PCl}_{5\left(g\right)}+{Cl}_{2\left(g\right)}$ at constant pressure and temperature then equilibrium constant of reaction:

• A. Increase
• B. Decrease
• C. Unchange
• D. Nothing can be said

Answer 1

The correct option is C Unchange

Given : If some

HeHe gas is introduced into the equilibrium PCl5(g)⇌PCl5(g)+Cl2(g)PCl5(g)⇌PCl5(g)+Cl2(g) at constant pressure and temperature then equilibrium constant of reaction:

Solution :

Kc will be unchanged because it depends on temperature only. I am giving you some more detail. Consider the dissociation equilibrium of $PC{l}_5$ : $PC{l}_5$ (g) ⇌ $PC{l}_3$ (g) + $C{L}_2$ (g) According to law of chemical equilibrium , equilibrium constant (Kc) : Kc = [$PC{l}_3$] [$C{L}_2$][$PC{l}_5$] . If an inert gas is added at constant volume then there is no effect on the dissociation of a compound as only the total pressure of the system increases and there is no change in the partial pressures of the gases. Hence , there will be not effect on the state of equilibrium.

The Correct Opt = C