40 % of HI undergoes decomposition to H_2 and I_2 at 300 K. Δ G^ for this decompostion reaction at one atmopsphere pressure is \ \ \ \ J…

$\displaystyle 40 \%$ of HI undergoes decomposition to $\displaystyle \mathrm{H}_2$ and $\displaystyle \mathrm{I}_2$ at $\displaystyle 300 \mathrm{~K} . \Delta \mathrm{G}^{\ominus}$ for this decompostion reaction at one atmopsphere pressure is \_\_\_\_ $\displaystyle \mathrm{J} \mathrm{mol}^{-1}$.[nearest integer] (Use $\displaystyle \mathrm{R}=8.31 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1} ; \log 2=0.3010, \ln 10=2.3, \log 3=0.477$ )