Question

\( E^0_{\text{Fe}^{2+}/\text{Fe}} \) / Fe = x volts, \( E^0_{\text{Fe}^{3+}/\text{Fe}^{2+}} \) = y volts.
Calculate \( E^0_{\text{Fe}^{2+}/\text{Fe}^{3+}} \) in volts.

• A. \( 3x - 2y \)
• B. \( 3y - 2x \)
• C. \( 2x - 3y \)
• D. \( 2y - 3x \)

Answer 1

The Correct Option is C

Step 1: Identify the relevant equations.
From the standard electrode potential relations, we can write:
(i) \( \text{Fe}^{2+}(aq) + 2e^{-} \rightarrow \text{Fe}(s) \) ..... \( \Delta G^\circ_1 \)
(ii) \( \text{Fe}^{3+}(aq) + 3e^{-} \rightarrow \text{Fe}(s) \) ..... \( \Delta G^\circ_2 \)
(iii) \( \text{Fe}^{2+}(aq) \rightarrow \text{Fe}^{3+}(aq) + e^{-} \) ..... \( \Delta G^\circ_3 \)
Step 2: Use the relations between the standard electrode potentials.
We know the following relationships:
From (i), we can relate \( E_1 \) to \( E_2 \), and from (ii) we know \( E_2 \) is related to \( E_3 \). \[ E_3 = 2x - 3y \]
Step 3: Final Answer.
Thus, the correct relation for \( E\(^0\)Fe²+/Fe³+ ) is \( 2x - 3y \). Final Answer: \( 2x - 3y \)