Potassium Carbonate USP Grade Specifications:
K2CO3 (anhydrous) --- 138.21
K2CO3-1½ H2O --- 165.23
Carbonic acid, dipotassium salt;
Dipotassium carbonate CAS 584-08-7

DEFINITION
Potassium Carbonate contains NLT 99.5% and NMT 100.5% of K2CO3, calculated on the dried basis.

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. Titrate with 1 N hydrochloric acid. Each mL of 1 N hydrochloric acid is equivalent to 69.11 mg of K2CO3.
Acceptance criteria: 99.5% to 100.5% on the dried basis

Specifications of Potassium Carbonate BP Grade
K2CO3

DEFINITION
Content: 99.0 per cent to 101.0 per cent (dried substance).

CHARACTERS
Appearance: White or almost white granular powder, hygroscopic.
Solubility: Freely soluble in water, practically insoluble in ethanol (96 per cent).

IDENTIFICATION
A. Dissolve 1 g in 10 ml of water. The solution is strongly alkaline.
B. 2 ml of the solution prepared for identification test A gives the reaction of carbonates and bicarbonates.
C. 1 ml of the solution prepared for identification test A gives reaction of potassium.

TESTS
Solution S: Dissolve 10.0 g in 25 ml of distilled water. Slowly add 14 ml of hydrochloric acid. When the effervescence has ceased, boil for a few minutes. Allow to cool and dilute to 50 ml with distilled water.
Appearance of solution: Solution S is not more opalescent than reference suspension and not more intensely coloured than reference solution.
Chlorides: Maximum 100 ppm.
Sulphates: Maximum 100 ppm.
Calcium: Maximum 100 ppm.
Iron: Maximum 10 ppm.
Heavy metals: Maximum 20 ppm.
Loss on drying: Maximum 5.0 per cent, determined on 0.300 g by drying in an oven at 120-125C for 5 h.

Specifications of Potassium Carbonate FCC Food Grade
K2CO3 Formula wt, anhydrous 138.21
K2CO3-1½H2O Formula wt, hydrated 165.23
INS: 501(i) CAS: 584-08-7

DESCRIPTION
Potassium Carbonate is anhydrous or contains 1.5 molecules of water of crystallization. The anhydrous form occurs as a white, granular powder, and the hydrated form as small, white, translucent crystals or granules. It is very deliquescent, and its solutions are alkaline. One gram dissolves in 1 mL of water at 25C and in about 0.7 mL of boiling water. It is insoluble in alcohol.
Function: pH control.

REQUIREMENTS
Identification: A 1:10 aqueous solution gives positive tests for Potassium and for Carbonate.
Assay: Not less than 99.0% and not more than 100.5% of K2CO3 after drying.
Insoluble Substances: Passes test.
Lead: Not more than 2 mg/kg.
Loss on Drying Anhydrous: Not more than 1%; Hydrated: Between 10.0% and 16.5%.

Specifications of Potassium Carbonate Anhydrous Analytical Reagent
Potassium Carbonate, Anhydrous
K2CO3
Formula Weight 138.21
CAS Number 584-08-7

REQUIREMENTS
Assay: 99.0% K2CO3 min

REQUIREMENTS
Assay: 99.0% K2CO3 min

MAXIMUM ALLOWABLE
Insoluble matter: 0.01%
Chloride (as Cl): 0.003%
Nitrogen compounds (as N): 0.001%
Phosphate (PO4): 0.001%
Silica (SiO2): 0.005%
Sulfur compounds (as SO4): 0.004%
Ammonium hydroxide precipitate 0.01%
Heavy metals (as Pb): 5 ppm
Iron (Fe): 5 ppm
Calcium: 0.005%
Magnesium: 0.002%
Sodium (Na): 0.02%

Specifications of Potassium Carbonate Sesquihydrate Analytical Reagent
Potassium Carbonate Sesquihydrate
K2CO3 . 1.5H2O
Formula Wt 165.23
CAS Number 6381-79-9

REQUIREMENTS
Assay: 98.5-101.0% K2CO3 . 1.5H2O
Loss on heating at 285C: 14.0-16.5%

MAXIMUM ALLOWABLE
Insoluble matter: 0.01%
Chloride (as Cl): 0.003%
Nitrogen compounds (as N): 0.001%
Phosphate (PO4): 0.001%
Silica (SiO2): 0.005%
Sulfur compounds (as SO4): 0.004%
Ammonium hydroxide precipitate: 0.01%
Heavy metals (as Pb): 5 ppm
Iron (Fe): 5 ppm
Calcium (Ca): 0.005%
Magnesium (Mg): 0.002%
Sodium (Na): 0.02%.