KMnO4 --- 158.0
DEFINITION
Content:
99.0 per cent to 100.5 per cent.KMnO4.
CHARACTERS
Appearance:
Dark purple or brownish-black, granular powder or dark purple or almost black crystals, usually having a metallic luster.
Solubility:
Soluble in cold water, freely soluble in boiling water.
It decomposes on contact with certain organic substances.
IDENTIFICATION
A. Dissolve about 50 mg in 5 ml of water and add 1 ml of ethanol (96 per cent) and 0.3 ml of dilute sodium hydroxide solution. A green colour develops. Heat to boiling. A dark brown precipitate is formed.
B. Filter the mixture obtained in identification test A. The filtrate gives reaction of potassium.
TESTS
Solution S:
Dissolve 0.75 g in 25 ml of distilled water, add 3 ml of ethanol (96 per cent) and boil for 2-3 min. Cool, dilute to 30 ml with distilled water and filter.
Appearance of solution:
Solution S is colourless.
Substances insoluble in water:
Maximum 1.0 per cent.
Chlorides:
Maximum 200 ppm.
Sulphates:
Maximum 500 ppm.
KMnO4 158.03 --- 7722-64-7.
Permanganic acid (HMnO4), potassium salt.
KMnO4 contains not less than 99.0 percent and not more than 100.5 percent of KMnO4, calculated on the dried basis.
Caution: Observe great care in handling Potassium Permanganate, as dangerous explosions may occur if it is brought into contact with organic or other readily oxidizable substances, either in solution or in the dry state.
Identification: A solution of it is deep violet-red when concentrated and pink when highly diluted, and responds to the tests for Permanganate.
Loss on drying: Dry it over silica gel for 18 hours: it loses not more than 0.5% of its weight.
Insoluble substances: Dissolve 2.0 g in 150 mL of water that previously has been warmed to steam-bath temperature, and filter immediately through a tarred, medium-porosity filtering crucible. Wash the filter with three 50-mL portions of the warm water, and dry the filtering crucible and the residue at 105 for 3 hours: not more than 4 mg of residue is obtained (0.2%).
KMnO4 --- 158.03 --- 7722-64-7
REQUIREMENTS
Assay: 99.0% KMnO4 min
MAXIMUM ALLOWABLE
Insoluble matter: 0.2%
Chloride and chlorate (as Cl): 0.005%
Nitrogen compounds (as N): 0.005%
Sulfate (SO4): 0.02%
