Titrations!

Chemistry Level 4

A 2 g sample of $$\ce{MnSO4.4H2O}$$ containing some other inert impurities is strongly heated in air. The residue ($$\ce{Mn3O4}$$) left was dissolved in 100 ml of 0.1 N $$\ce{FeSO4}$$ .

The excess of ferrous ions left in solution were titrated with 50 ml of $$\ce{KMnO4}$$ solution in acidic medium.

25 ml of this same stock solution of $$\ce{KMnO4}$$ solution was completely reduced by 30 ml of 0.1 N $$\ce{FeSO4}$$ solution.

Calculate the percent purity of the sample to the nearest integer value.

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