Chemical Equilibrium

At $T(\mathrm{~K})$, the equilibrium constant for the reaction $a A(g) \rightleftharpoons b B(g)$ is $K_c$. If the reaction takes place in the following form $2 a A(g) \rightleftharpoons 2 b B(g)$, its equilibrium constant is $K^{\prime}{ }_c$. The correct relationship between $K_c$ and $K^{\prime}{ }_C$ is