Chemistry · Ch 4 — Transition and Inner Transition Elements
Uses of Potassium Permanganate
Uses of Potassium Permanganate
Potassium permanganate finds a wide range of important practical applications, five of which are highlighted in the chapter. First and most generally, it serves as a strong oxidising agent in numerous laboratory and industrial contexts. Second, it is used medically for the treatment of various skin infections and fungal infections of the foot, where dilute potassium permanganate solution's antiseptic, oxidising action helps control microbial growth. Third, it is used in water-treatment industries specifically to remove dissolved iron and hydrogen sulphide from well water, oxidising both troublesome contaminants into insoluble or non-odorous forms that can then be filtered out. Fourth, it serves, in its cold dilute alkaline form, as Baeyer's reagent, used for detecting carbon-carbon unsaturation in an organic compound (developed fully in section 4.4.3.4). Fifth, and of particular importance to the analytical chemistry already worked through in section 4.4.3.4, potassium permanganate is extensively used in quantitative volumetric analysis for the estimation of ferrous salts, oxalates, hydrogen peroxide, and iodides. …
Worked out. Equivalent weight = molecular weight (158 g mol⁻¹) ÷ number of moles of electrons transferred per formula unit. In acid medium (5-electron change, MnO₄⁻ → Mn²⁺): 158/5 = 31.6. In basic/alkaline medium (1-electron change, MnO₄⁻ → MnO₄²⁻): 158/1 = 158. In neutral medium (3-electron change, MnO₄⁻ → MnO₂): 158/3 = 52.67. This is why the same molar quantity of KMnO₄ delivers very different oxidising capacity depending on t …