Chemistry - Complete d-block Question with Solution | TestHub

Mn³⁺ (3d⁴) is readily reduced to the more stable Mn²⁺ (3d⁵, half-filled configuration).

Therefore, the reduction Mn³⁺ + e⁻ → Mn²⁺ has a positive E° value.

Sc, Ti, and V do not gain such exceptional stability on reduction to the +2 state.

Hence, the correct answer is (D) Mn.