The standard Gibbs energy of the following reaction is $-610\, kJ\, mol^{-1}$

$Mg(s) + 2Ag^+ (aq) → Mg^{2+}(aq) + 2Ag(s)$

What is the standard EMF for the cell corresponding to the above reaction?

Given: Faraday's constant = $96500\, C\, mol^{-1}$

+3.16 V

The correct answer is Option (3) → +3.16 V

Use the relation between standard Gibbs energy change and standard EMF:

$\Delta G^\circ = -n F E^\circ_{\text{cell}}$​

Given:

• $\Delta G^\circ = -610 \text{ kJ mol}^{-1} = -610000 \text{ J mol}^{-1}$
• n = 2 (Mg → Mg²⁺ + 2e⁻)
• $F = 96500 \text{ C mol}^{-1}$

Calculation:

$E^\circ_{\text{cell}} = \frac{-\Delta G^\circ}{nF} = \frac{610000}{2 \times 96500} \approx 3.16 \text{ V}$