Potassium permanganate

Potassium permanganate (KMnO₄) is an inorganic salt composed of potassium ions and permanganate ions. It is a strong oxidizing agent that forms purple solutions.

Permanganate ion: The tetrahedral MnO₄⁻ anion, in which manganese is in the +7 oxidation state. This anion gives the salt its strong oxidizing behavior and characteristic purple color.
Permanganate titration: A volumetric redox analysis that uses permanganate solution as the titrant and often as its own indicator. Its oxidizing power and visible endpoint make the salt useful in quantitative analysis.
Ionic compound: A compound composed of positively and negatively charged ions held together by electrostatic attraction. Potassium permanganate pairs K⁺ cations with MnO₄⁻ anions.
Potassium dichromate: An orange crystalline salt, K₂Cr₂O₇, containing dichromate ions and used as an oxidizing agent. It is a strong analytical oxidant like permanganate, but contains toxic chromium(VI).
Redox reaction: A chemical reaction involving transfer of electrons and changes in oxidation states. Permanganate accepts electrons as it oxidizes other substances.
Chemical oxygen demand: A measure of the oxygen equivalent required to chemically oxidize substances in a water sample. Permanganate oxidation is used in some methods for measuring oxidizable matter in water.
Potassium ion: The positively charged K⁺ ion formed when a potassium atom loses one electron. Potassium ions balance the permanganate anion’s negative charge in the salt.
Hydrogen peroxide: A compound, H₂O₂, that can act as either an oxidizing or reducing agent depending on reaction conditions. Its redox role is more condition-dependent than permanganate’s typical oxidizing behavior.
Manganese: A metallic chemical element with atomic number 25 and several common oxidation states. Manganese’s +7 state in permanganate accounts for its strong tendency to be reduced.
Water treatment: Processes that improve water quality for human use or environmental release. Permanganate can oxidize iron, manganese, and some taste- and odor-causing compounds during treatment.

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