Use Faraday’s laws: Weight deposited = \(\frac{E I t \cdot M}{n F}\).
Here, \(E = 3\) A, \(t = 3600\) s, \(M = 106.4\) g/mol, \(F = 96500\) C/mol, and deposited mass = 2.977 g.
Solving gives \(n = 4\).
\( \Delta G^\circ \, (\text{in kJ mol}^{-1}) \text{ for the cell reaction is} \)
\( \text{Cu}^{2+}(aq) + \text{Fe}(s) \rightarrow \text{Fe}^{2+}(aq) + \text{Cu}(s) \)
\( \left[\text{Given} \, E^\circ_{\text{Cu}^{2+}/\text{Cu}} = 0.34 \, \text{V}, \, E^\circ_{\text{Fe}^{2+}/\text{Fe}} = -0.44 \, \text{V} \, \text{and} \, F = 96,500 \, \text{C mol}^{-1} \right] \)