The reaction occurred between permanganate ions and iron(II) ions in an acidic solution. The products include manganese(II) ions and iron(III) ions. We can write:
MnO4- + Fe2+ → Mn2+ + Fe3+             (H+)

The (H+) is to remind us that the solution was acidic.

The steps:

  • break the reaction into half-reactions
    MnO4- → Mn2+             Fe2+ → Fe3+
  • check the common atoms for balance and balance oxygen with water
    MnO4- → Mn2+ + 4 H2O             Fe2+ → Fe3+