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SYNONYMS |
INS No. 261 |
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DEFINITION |
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Chemical names |
potassium acetate |
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C.A.S. number |
127-08-2 |
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Chemical formula |
C 2 H 3 KO 2 |
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Structural formula |
CH 3 -COOK |
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Formula weight |
98.14 |
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Assay |
Not less than 99.0% after drying |
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DESCRIPTION |
Colourless, deliquescent crystals or a white, crystalline powder, odourless or with a faint acetic odour |
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FUNCTIONAL USES |
Buffer, antimicrobial preservative |
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CHARACTERISTICS |
IDENTIFICATION |
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Solubility (Vol. 4) |
Very soluble in water; freely soluble in ethanol |
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pH (Vol. 4) |
7.5 - 9.0 (1 in 20 soln) |
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Test for potassium (Vol. 4) |
Passes test |
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Test for acetate (Vol. 4) |
Passes test |
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PURITY |
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Loss on drying (Vol. 4) |
Not more than 8.0% (150 o , 2 h) |
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Alkalinity |
Dissolve 1 g of the sample in 20 ml of freshly boiled and cooled water, and add 3 drops of phenolphthalein TS. If a pink colour is produced, not more than 0.5 ml of 0.1 N hydrochloric acid should be required to discharge it. |
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Test for sodium (Vol. 4) |
Negative test |
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Lead (Vol. 4)
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Not more than 2 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, ¡°Instrumental Methods.¡± |
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METHOD OF ASSAY |
Dissolve about 200 mg of the dried sample, accurately weighed, in 25 ml of glacial acetic acid. Add 2 drops of crystal violet TS, and titrate with 0.1 N perchloric acid in glacial acetic acid. Perform a blank determination, and make any necessary correction. Each ml of 0.1 N perchloric acid is equivalent to 9.814 mg of C 2 H 3 KO 2 |
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