Some titrimetric applications of manganese(III) salt solutions: analysis of higher valent complexes of manganese and nickel

Abstract

Mn₂(SO₄)₃, prepared by oxidising 0.1 M MnSO₄ solution in 6 M H₂SO₄ with 0.02 M KMnO₄, was used for titrating solutions of hydrazine or ascorbic acid. The kinetics of dissolution of manganese dioxide in ascorbic acid solution were followed by titration against Mn₂(SO₄)₃ solution. Mn^III, Ni^III or Mn^III+ Mn^IV were determined in prepared solids by adding a known excess of ascorbic acid solution, which reduces the metal to the divalent state, and back-titrating with Mn₂(SO₄)₃ solution. Although the latter solution can be successfully used for titrating H₂O₂ or Fe^II, even in the presence of high concentrations of chlorides, it is not recommended for titrating nitrites or lower vanadium compounds.