The equilibrium concentrations of the species in the reaction A + B ⇋ C + D are 2 , 3 , 10 and 6 mol L - 1…

$$\begin{gathered} \mathrm{A}+\mathrm{B}\iff \mathrm{C}+\mathrm{D} \\ \mathrm{at} \mathrm{equilibrium} 2 3 10 6 \end{gathered}$$

$$\begin{gathered} {\mathrm{K}}_{\mathrm{eq} }=\frac{ \left[\mathrm{C}\right] \left[\mathrm{D}\right]}{ \left[\mathrm{A}\right] \left[\mathrm{B}\right] } \\ {\mathrm{K}}_{\mathrm{eq} }=\frac{10\times 6}{2\times 3}=10 \\ ∆\mathrm{G}º = –\mathrm{RT} \ln \mathrm{K} \end{gathered}$$

Where $\mathrm{R}$ is the gas constant,$\mathrm{T}$is the temperature in Kelvin, and$\mathrm{K}$ is the equilibrium constant of the reaction.

$$\begin{gathered} \mathrm{\Delta G} =-2.303\times 2\times 300\times {\log }_{10}10 \\ =-2.303\times 2\times 300\times 1 \\ =-1381.8 \mathrm{cal} \end{gathered}$$