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, $ΔG^0$ will be $(F=96500 \, C \, mol^{-1})$

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

Answer 1

Answer: (A)

- 89.0 kJ

Answer 2

We know that, standard Gibbs energy,
$ΔG^0=-nFE^0_{cell}$
For the cell reaction,
$2Ag^+\, +Cu \rightarrow Cu^{2+}+2 \, Ag$
$ΔE_{cell}^0=+0.46 \, V$
$ΔG^0=-nFE^0_{cell}$
n=2
$ΔG^0=-2 \times 96500 \times 0.46$
= - 88780 J
= - 88.7 k J $\approx -89.0 kJ$