A 3.9 g sample of an iron ore was dissolved in an acid solution and all of the iron converted to the +2 oxidation state. The resulting solution took 21.1 mL of 0.0700 M KMnO4 solution to titrate to a light pink color. The Fe+2 is oxidized to Fe+3 and the MnO4- is reduced to Mn+2. What was the percent iron in the ore? Answer in units of %.
Moles KMnO4 0.0211 L x 0.0700 0.00148 8H+ + MnO4- + 5Fe2+ 5Fe3+ + Mn2+ + 4 H2O Moles Fe2+ 5 x 0.00148 0.00740 Mass 0.00740 x 55.847 g/mol 0.413 g % Fe 0.413 x 100 / 3.9 10.6
