Question

The number of moles of MnO4 and Cr2O7
Iseparately required to oxidise one mole of
FeC,0, each in acidic medium respectively
1) 0.5 ; 0.6
2) 0.6 ; 0.4
3) 0.4 ; 0.5
4) 0.6 ; 0.5
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Answer 1

Answer:

Option (4) 0.6 ; 0.5

Explanation:

For MnO₄⁻, the balanced chemical reaction is

10FeC₂O₄ + 6KMnO₄ + 24H₂SO₄ → 3K₂SO₄+ 6MnSO₄ + 5Fe₂(SO4)₃ + 24H₂O + 20CO₂

∵ 6 moles of KMnO₄ is required to oxidise 10 moles of FeC₂O₄

∴1 mole of FeC₂O₄  will be oxidised by = 6/10 = 0.6 moles of KMnO₄

For Cr₂O₇²⁻, the balanced chemical reaction is

2FeC₂O₄ + K₂Cr₂O₇ + 7H₂SO₄ → K₂SO₄+ Cr₂(SO₄)₃ + Fe₂(SO4)₃ + 7H₂O + 4CO₂

∵ 1 moles of K₂Cr₂O₇ is required to oxidise 2 moles of FeC₂O₄

∴1 mole of FeC₂O₄  will be oxidised by = 1/2 = 0.5 moles of K₂Cr₂O₇

Thus, the correct option is option (4)