Choose the correct products formed in acidic medium. ${5SO_3}^{-}2+ 2{MnO_4}^- + 6H^+→?$ |
$2MnO_2 + 6H^+ + 5{SO_4}^{2-}$ $2Mn^{2+} + 3H_2O + 5{SO_4}^{2-}$ $2Mn^{2+}+ 5{SO_4}^{2-} + 60H^-$ $2MnO_2 + 6H_2O +5/2{S_2O_3}^{2-}$ |
$2Mn^{2+} + 3H_2O + 5{SO_4}^{2-}$ |
The correct answer is Option (2) → $2Mn^{2+} + 3H_2O + 5{SO_4}^{2-}$ This is a redox reaction in acidic medium. Permanganate ion (MnO₄⁻) in acidic medium is reduced to Mn²⁺. Reduction half reaction: MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O Sulphite ion (SO₃²⁻) is oxidised to sulphate (SO₄²⁻). Oxidation half reaction: SO₃²⁻ + H₂O → SO₄²⁻ + 2H⁺ + 2e⁻ Balancing electrons and combining both half reactions gives: 5SO₃²⁻ + 2MnO₄⁻ + 6H⁺ → 5SO₄²⁻ + 2Mn²⁺ + 3H₂O Thus the products are: 2Mn²⁺ + 3H₂O + 5SO₄²⁻ Option 1: 2MnO₂ + 6H⁺ + 5SO₄²⁻ MnO₂ forms in neutral or weakly acidic medium, not strongly acidic medium. Incorrect. Option 2: 2Mn²⁺ + 3H₂O + 5SO₄²⁻ --- Correct products in acidic medium. Correct. Option 3: 2Mn²⁺ + 5SO₄²⁻ + 6OH⁻ OH⁻ cannot appear in acidic medium. Incorrect. Option 4: 2MnO₂ + 6H₂O + 5/2 S₂O₃²⁻ Thiosulphate is not formed in this reaction. Incorrect. |