KMnO4+Fecl2+HCl

KMnO4 + HCl + FeCl2 = FeCl3 + MnCl2 + KCl + H2O

KMnO4, HCl, and FeCl2 are the reactants of the above reaction. But we have to know that the HCl is this reaction is creating the acidic environment for the reaction. If we consider the oxidation number of each of the reactants of the above reaction, we can notice that there are some electrons exchanging among the ions of the reactants. Let’s understand it first.

Exchange of electron among KMnO4, HCl, and FeCl2

The reaction is-

KMnO4 + HCl + FeCl2 = KCl + MnCl2 + H2O + FeCl3

If we focus on the oxidation number of Mn (Manganese) and Fe (Iron),

KMn(7+)O4 + HCl + Fe(2+)Cl2 = KCl + Mn(2+)Cl2 + H2O + Fe(3+)Cl3

Here,  Mn release 5 electrons, on the other hand, Fe accepts only one electron. That means what? can you answer it? Yes, you are right. The reaction is an electron exchanging reaction, e.i. it is a redox (Oxidation-Reduction reaction). This type of reaction can be balanced very easily by the ion-electron method. Now we learn how to use the ion-electron method to balance the reaction. 

Reactants of the reaction

The names of the reactant chemicals as follows-

  • KMnO4 = Potassium permanganate which is Oxidizing agent (as ion MnO-1)
  • FeCl2Iron(II) chloride which is Reducing agent (as ion Fe2+)
  • HCl Hydrochloric acid (creates an acidic environment)

When potassium permanganate reacts in Hydrochloric acid with iron(II) chloride

The skeleton reaction of Potassium permanganate and Iron(II) chloride in Hydrochloric acid (KMnO4 + HCl + FeCl2) is–

KMnO4 + HCl + FeCl2 = KCl + MnCl2 + H2O + FeCl3

Here, Fe(2+) accept one electron released by Mn(7+). So,

Oxidation Half Reaction

⇒ Fe2+ – e = Fe3+ … … … (1)

On the other hand, Mn(7+) released 5 electrons and become Mn(2+). So,

Reduction Half Reaction

⇒ MnO-1 + 5e + 8H = 4H2O + Mn2-  … …. …. …. (3)

Now,  the Oxidizing agent released 5 electrons, on the other hand, reducing agent accepts only one electron at a time. Therefore, the reducing agent FeCl2 Iron(II) chloride needed five times than the oxidizing agent KMnO4 (Potassium permanganate). That’s means equation (1)x5.

After that, we add both half-reactions (Oxidation Half Reaction equation 1 and Reduction Half Reaction equation 2) to make the full oxidation-reduction reaction (Redox) reaction.

MnO-1 +5e + 8H = Mn2- + 4H2O

5Fe2+ – 5e = 5Fe3+


MnO-1 + 8H+ 5Fe2+ = Mn2-  + 5Fe3+ + 4H2O

Do you remember that we excluded the K+ and Cl ions for our calculation benefit? At this point, we must add the ions to fulfill the balanced redox reaction.

Adding necessary ions and radicals

KMnO+ 8HCl + 5FeCl2 = KCl + MnCl2  + 5FeCl3 + 4H2O

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