Potassium Carbonate
K2CO3 (anhydrous) 138.21
K2CO3·1½H2O 165.23
Carbonic acid, dipotassium salt;
Dipotassium carbonate
[584-08-7].
(poe tas' ee um kar' bo nate).
K2CO3 (anhydrous) 138.21
K2CO3·1½H2O 165.23
Carbonic acid, dipotassium salt;
Dipotassium carbonate
[584-08-7].DEFINITION
Potassium Carbonate contains NLT 99.5% and NMT 100.5% of K2CO3, calculated on the dried basis.
IDENTIFICATION
• A. Identification Tests—General, Potassium 
191
:
Meets the requirements
191:
Meets the requirements
• B. Identification Tests—General, Carbonate 191:
Meets the requirements
191:
Meets the requirements
ASSAY
• Procedure
Sample:
Dried potassium carbonate obtained in the test for Loss on Drying
Analysis:
Transfer the Sample to a flask with the aid of 150 mL of water, and add 4 drops of methyl orange TS. Titrate with 1 N hydrochloric acid VS. Each mL of 1 N hydrochloric acid is equivalent to 69.11 mg of K2CO3.
Acceptance criteria:
99.5%–100.5% on the dried basis
IMPURITIES
• Heavy Metals 231
231
Analysis:
Dissolve 4.0 g in 10 mL of water. Add 15 mL of 3 N hydrochloric acid, and heat to boiling. Add 1 drop of phenolphthalein TS, and neutralize with 1 N sodium hydroxide until the solution is faintly pink in color. Cool, and dilute with water to 25 mL.
Acceptance criteria:
NMT 5 ppm
SPECIFIC TESTS
• Loss on Drying 731:
Dry a sample at 180
for 4 h: it loses NMT 0.5% of its weight.
731:
Dry a sample at 180 for 4 h: it loses NMT 0.5% of its weight.
• Insoluble Substances
Sample solution:
1 g in 20 mL of water
Acceptance criteria:
The solution is complete, clear, and colorless.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Sujatha Ramakrishna, Ph.D.
Senior Scientific Liaison 1-301-816-8349 |
(SM22010) Monographs - Small Molecules 2 |
USP35–NF30 Page 4359