Question

Here is a more complex redox reaction involving the permanganate ion in acidic solution: 5fe2+ + 8h+ + mno4? ? 5fe3+ +mn2+ + 4h2o

Answer 1

5Fe²⁺ + 8H⁺ + MnO₄⁻ → 5Fe³⁺ + Mn²⁺ + 4H₂O

Fe²⁺ - 1e⁻ → Fe³⁺                                  n=1
MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O    n=5

for example:
10FeSO₄ + 8H₂SO₄ + 2KMnO₄ → 5Fe₂(SO₄)₃ + 2MnSO₄ + K₂SO₄ + 8H₂O