For the reaction, FeS₂ + KMnO₄ + H⁺ → Fe³⁺ + SO₄ ²⁻ + Mn²⁺ + H₂O, if the molar mass of FeS₂ is M, then the equivalent mass of FeS₂ would be equal to:
Correct answer: D. M/15
- A. M
- B. M/10
- C. M/11
- D. M/15
Explanation
In this reaction, Fe goes from +2 to +3 (loss of 1 e⁻) and each of the two S atoms goes from -1 to +6 (loss of 2×7=14 e⁻). The total number of electrons lost per formula unit of FeS₂ is 1 + 14 = 15. Therefore, the equivalent mass is M/15.
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