The gas phase reaction
$2 \mathrm{~A}(\mathrm{~g}) \rightleftharpoons \mathrm{A}_2(\mathrm{~g})$ at $400 \mathrm{~K}_{\text {has }} \Delta \mathrm{G}^0=+25.2 \mathrm{~kJ} \mathrm{~mol}^{-1}$.
The equilibrium constant KC for this reaction is $\_\_\_\_$ $\times 10^{-2}$. (Round off to the Nearest integer)
[Use: $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$, In $102.3 \log _{10} 2=0.30$, $1 \mathrm{~atm}=1$ bar] $\quad$ [antilog $(-0.3)=0.501$ ]