STANDARDChemistry-Redox Reactions
STANDARD Chemistry Balancing Redox Equations MCQ Question
Type: MCQ-numerical-Hard-Class 11
What will be the balanced equation in acidic medium for the given reaction? Cr₂O₇²⁻(aq) + SO₂(g) → Cr³⁺(aq) + SO₄²⁻(aq)
A
Cr₂O₇²⁻(aq) + 3SO₂(g) + 2H⁺(aq) → 2Cr³⁺ + 3SO₄²⁻(aq) + H₂O(l)
B
2Cr₂O₇²⁻(aq) + 3SO₂(g) + 4H⁺(aq) → 4Cr³⁺ + 3SO₄²⁻(aq) + 2H₂O(l)
C
Cr₂O₇²⁻(aq) + 3SO₂(g) + 4H⁺(aq) → 2Cr³⁺(aq) + 3SO₄²⁻(aq) + 7H₂O(l)
D
Cr₂O₇²⁻(aq) + 6SO₂(g) + 7H⁺(aq) → 2Cr³⁺ + 6SO₄²⁻(aq) + 7H₂O(l)
Correct Answer
Option A
Detailed Explanation
The balanced equation in acidic medium is obtained by balancing the oxidation and reduction half-reactions separately. The oxidation of SO₂ to SO₄²⁻ and the reduction of Cr₂O₇²⁻ to Cr³⁺ are balanced using H⁺ ions and water to ensure both mass and charge balance.
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