• # question_answer                 For the cell reaction,                 $C{{u}^{2+}}({{C}_{1}}\,aq)+Zn(s)\rightleftharpoons Z{{n}^{2+}}({{C}_{2}}\,aq)+Cu(s)$                                                                               of an electrochemical cell. The change in free energy $(\Delta G)$ at a given temperature is a function of: A)                                                                                                                                                            $\ln \,({{C}_{1}})$ B)                                            $\ln \,({{C}_{2}}/{{C}_{1}})$                      C)                 $\ln \,({{C}_{2}})$                          D)                 $\ln \,({{C}_{1}}+{{C}_{2}})$

$\Delta G=-n{{E}^{o}}\,F$                 For concentration cell                 $E=\frac{RT}{nF}\ln \,\frac{{{C}_{2}}}{{{C}_{1}}}$                 In it R, T, n and F are constant.                 So E is based upon- In ${{C}_{2}}/{{C}_{1}}$                 $\Delta G=-nEF$                 $=-nF\times \frac{RT}{nF}\ln \frac{{{C}_{2}}}{{{C}_{1}}}=-RT\,\ln \,\frac{{{C}_{2}}}{{{C}_{1}}}$                 So, at constant temperature $\Delta G$ depends upon In $\ln \,{{C}_{2}}/{{C}_{1}}$