The equilibrium optical density, due to a higher manganese chloride, of a solution of manganese- (II) in concentrated hydrochloric acid oxidized by chlorine obeys the relation D = Ke[Mn++] [Cl2]1/2, implying that the colored species is a chloro-complex of manganese(III) formed by the reaction Mn+++ 1/2Cl2= MnIII+ Cl−. The extinction coefficients of manganese(III) were measured, and the equilibrium constant, K = [MnIII]/[Mn++][Cl2]1/2(liter/moles),1/2in 10.1 F hydrochloric acid was evaluated as 0.19 (25°) and 0.33 (0°). There is no optical interaction absorption in mixed solutions of manganese(II) and (III). Spectrophotometric evidence for the formation of chloro-complexes of manganese(II) is presented. The ratio of the amount of tripositive manganese to the amount of chlorine formed by the reaction of permanganate with a manganese(II) solution in hydrochloric acid has been investigated.
ASJC Scopus subject areas
- Colloid and Surface Chemistry