Question

How many moles of KMnO4 are equivalent to 1.000 mole of Fe2+?

Answer 1

Potassium Permanganate(KMnO₄₎ reduces to a manganese(II) ion in the acidic solution. This reaction requires 5 electrons and 8 hydrogen ions.The balanced equation is

                               MnO₄^-+ 8H⁺ + 5 e^- Mn²⁺ + 4H₂O

For the reduction of Fe(III) to Fe(II) only one electron is necessary,The balanced equation is

                                               Fe³⁺ + e^- Fe²⁺

Therefore, 1 mole of MnO₄^-(the oxidizing agent) reacts with 5 moles of Fe²⁺ (the reducing agent) to form 5 moles of Fe³⁺ and 1 mole of Mn²⁺. Thus, in net ionic form:

                            MnO₄^- + 5Fe²⁺ + 8H⁺ 5Fe³⁺ + Mn²⁺ + 4H₂O

From the balanced equation ,

1 mole of KMnO₄ reacts with 5 moles of Fe²⁺

M moles of KMnO₄ reacts with 1.000 moles of Fe²⁺

M = ( 1.000 x 1) / 5

   = 0.2 mole

Therefore the number of moles of KMnO₄ required is 0.2 mol