Question:

The standard reduction potential \(E^{\circ}\) for half reactions are,
\(\mathrm{Zn}\longrightarrow \mathrm{Zn}^{2+} + 2e^{-}; E^{\circ} = +0.76\mathrm{V}\)
\(\mathrm{Fe}^{2+} + 2e^{-}\longrightarrow \mathrm{Fe}; E^{\circ} = +0.41\mathrm{V}\)
The emf of the cell reaction \(\mathrm{Fe}^{2+} + \mathrm{Zn}\longrightarrow \mathrm{Zn}^{2+} + \mathrm{Fe}\) is

Show Hint

Always convert all values to reduction potentials before applying the formula.
Updated On: Apr 20, 2026
  • -0.35 V
  • +0.35 V
  • +1.17 V
  • -1.17 V
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

Step 1: Understanding the Concept:
\(E^{\circ}_{\text{cell}} = E^{\circ}_{\text{cathode}} - E^{\circ}_{\text{anode}}\).

Step 2: Detailed Explanation:
Convert Zn oxidation potential to reduction potential:
Zn\(^{2+}\) + 2e\(^-\) → Zn; \(E^{\circ} = -0.76\) V.
Fe\(^{2+}\) + 2e\(^-\) → Fe; \(E^{\circ} = +0.41\) V.
Now apply formula:
\[ E^{\circ}_{\text{cell}} = E^{\circ}_{\text{cathode}} - E^{\circ}_{\text{anode}} = (-0.76) - (0.41) = -0.35\ \text{V} \]

Step 3: Final Answer:
-0.35 V
Was this answer helpful?
0
0