The gas phase reaction \( 2A (g) \rightleftharpoons A_{2} (g) \) at \( 400 \, \mathrm{K} \) has \( \Delta G^{\circ} = +25.2 \, \mathrm{kJ \, mol^{-1}} \). The equilibrium constant \( K_c \) for this reaction is _____ \( \times 10^{-2} \).
[Use: \( R = 8.3 \, \mathrm{J \, mol^{-1} \, K^{-1}} \), \( \ln 10 = 2.3 \), \( \log_{10} 2 = 0.30 \), \( 1 \, \mathrm{atm} = 1 \, \mathrm{bar} \)]
[antilog \( (-0.3) = 0.501 \)]