Question

The standard electrode potential for Daniell cell is 1.1 V. The standard Gibbs free energy for the reaction Zn(s) + Cu$^{2+}$(aq) → Zn$^{2+}$(aq) + Cu(s) is approximately:

• A. -212.27 J/mol
• B. -21.22 J/mol
• C. -212271.4 J/mol
• D. -2.1227 J/mol

Answer 1

Answer: (A)

-212.27 J/mol

Answer 2

Using the formula for Gibbs free energy change, \Delta G^{\circ} = -n \times F \times E^{\circ} \\\ = -2 \times 96485 \text{ C/mol} \times 1.1 \text{ V} \\\ = -212271 \text{ J/mol} \\\ \approx -212.27 \text{ kJ/mol}$$\\\The calculation gives -212.27 J/mol as the result.