Chemistry - Redox Reactions Question with Solution | TestHub

Using the law of equivalence (Equivalents = Moles $\times$$n$-factor) in acidic medium:

Statement A & B (Incorrect): $n$-factor of MnO₄⁻ is 5 and Cr₂O₇²⁻ is 6, so 1 mole of each oxidizes 5 and 6 moles of Fe²⁺ ($n=1$) respectively.

Statement C (Incorrect): $n$-factor of Cu₂S $\to$ 2Cu²⁺ + SO₂ is 8 ($2\times 1$ for Cu + $6$ for S); thus 2 moles of Cu₂S ($16$ eq) require $16/5=3.2$ moles of MnO₄⁻.

Statement D (Correct): 2 moles of Cu₂S ($16$ eq) require $16/6=8/3$ moles of Cr₂O₇²⁻ ($n=6$).

Incorrect options: A, B, C