Question

For the reduction of silver ions with copper metal, the standard cell potential was found to be $+0.46\, V$ at $25^{\circ} C$. The value of standard Gibbs energy, $\Delta G^{\circ}$ will be
$\left(F=96500 \,C\,mol ^{-1}\right)$

• A. - 89.0 kJ
• B. - 89.0 J
• C. - 44.5 kJ
• D. - 98.0 kJ

Answer 1

Answer: (A)

We know that, standard Gibbs energy,
$\Delta G^{0}=-n F E_{\text {cell }}^{0}$
For the cell reaction,
$2 A g^{+}+C u \rightarrow C u^{2+}+2 A g$
$\Delta E_{c e l l}^{0}=+0.46 V$
$\Delta G^{0}=-n F E_{c e l l}^{0}$
$ n =2$
$\Delta G^{0}=-2 \times 96500 \times 0.46$
$=-88780 \,J $
$=-88.7 \,kJ \approx-89.0 \,kJ$