A-LevelChemistryElectrochemistry9701/12 · Feb/Mar 2022 · Q101 Mark
Two half-equations are shown. MnO₄⁻ + 2H₂O + 3e⁻ → MnO₂(s) + 4OH⁻ 2OH⁻ + SO₃²⁻ → SO₄²⁻ + H₂O + 2e⁻ The equation for the reaction between manganate(VII) ions and sulfite ions is shown. uMnO₄⁻ + vH₂O + wSO₃²⁻ → xMnO₂(s) + ySO₄²⁻ + zOH⁻ Which statements are correct? 1 u = x = z 2 Manganese is reduced to oxidation state +4. 3 Sulfur is oxidised from oxidation state +4 to +6.
A1, 2 and 3
B1 and 2 only
C1 and 3 only
D2 and 3 only
✓ Correct answer
A: 1, 2 and 3
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