0.1 N Potassium Permanganate VS
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
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0.1 N Potassium Permanganate VS
Dissolve about 3.3 g of potassium permanganate in 1000 mL of water in a flask, and boil the solution for about 15 min. Insert the stopper in the flask, allow it to stand for at least 2 days, and filter through a fine-porosity, sintered-glass crucible. If necessary, the bottom of the sintered-glass crucible may be lined with a pledget of glass wool.
Since potassium permanganate is reduced on contact with organic substances such as rubber, the solution must be handled in an apparatus made entirely of glass or other suitably inert material. It should be frequently restandardized. Store in glass-stoppered, amber-colored bottles.
Standardization
See Volumetric Solutions, 1. Introduction.
See Titrimetry ⟨541⟩.
Standardize by one of the following procedures.
[Note—Other standardization procedures may be used. See Volumetric Solutions, 2. Preparation and Standardization, 2.3 Standardization.]
Standardization with visual endpoint: Accurately weigh about 200 mg of primary standard sodium oxalate, dried according to the instructions on its label, or, if this information is not available, dried at 105° for 2 h, and dissolve it in 250 mL of water. Add 7 mL of sulfuric acid and 3 g of manganese sulfate. Titrate with the permanganate solution, with constant stirring, until a pale pink color, which persists for 15 s, is produced.
N = g Na₂C₂O₄/ mL KMnO₄ solution × 0.06700
Standardization with potentiometric endpoint: Accurately weigh about 80 mg of primary standard sodium oxalate, dried according to the instructions on its label or, if this information is not available, dried at 105° for 2 h, and dissolve it in 250 mL of water. Add 7 mL of sulfuric acid, and 2 g of manganese sulfate. Titrate with the permanganate solution, with constant stirring, using a combined platinum-electrode.
N = g Na₂C₂O₄/ mL KMnO₄ solution × 0.06700
▲ (ERR 1-Sep-2022)
[Note—If this volumetric solution is used in a qualitative application such as pH adjustment, dissolution medium, or diluent, its standardization is not required.]
