GKFix MCQ Question

Why is the standard electrode potential (E°) for the M³⁺/M²⁺ couple relatively high for Manganese (Mn)?

• A. The instability of the Mn³⁺ ion
• B. The ease of oxidizing Mn²⁺
• C. The exceptional stability of the Mn²⁺ ion with a d⁵ half-filled configuration makes further oxidation difficult
• D. The low hydration energy of Mn³⁺