Question

What solution and indicator should I use to determine a mixture of Mn and Fe?

Answer 1

For a mixture of Mn and Fe, we can assume the reaction of FeCl₂ and Potassium permanganate where Fe will undergo oxidation and Mn will undergo reduction.

We need to titrate the solution of Fecl₂ and KMnO₄. In here we need to add small amounts of SnCl^₂ and mercury(II) chloride in the Mn, Fe solution so that Fe will stay in Fe+3 state as it easily gets oxidized into Fe⁺³ from Fe⁺² and also by the addition of SnCl₂ and mercury(II) chloride will not reduce Mn only if SnCl₂ and mercury(II) chloride are added in small amounts.

So, for the titration, we need the 0.02M KMnO₄ solution, Reinhardt-Zimmermann solution, FeCl₂ solution initially acidified with HCl, SnCl₂, and Hg₂Cl₂ in small amounts and distilled water.

In here there is no need of indicator as the pink color of permanganate solution is enough to find out the titration status.