Question Detail
Question
When the equation Fe²⁺ + Cr₂O₇²⁻ → Fe³⁺ + Cr³⁺ is balanced in an acidic medium, the coefficient of Fe²⁺ is
Correct Answer
Option C is the correct answer.
Detailed Explanation
Balanced half-reactions: Fe²⁺ → Fe³⁺ + e⁻ (×6). Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O. Combined: 6Fe²⁺ + Cr₂O₇²⁻ + 14H⁺ → 6Fe³⁺ + 2Cr³⁺ + 7H₂O. Coefficient of Fe²⁺ is 6.
Hint
Balance the Cr first, then balance electrons.