Potassium Chloride

Potassium Chloride BP ZnCl2
DEFINITION
Content
95.0 per cent to 100.5 per cent.
CHARACTERS
Appearance
White or almost white, crystalline powder or cast in white or almost white sticks, deliquescent.
Solubility
Very soluble in water, freely soluble in ethanol (96 per cent) and in glycerol.
IDENTIFICATION
A. Dissolve 0.5 g in dilute nitric acid R and dilute to 10 ml with the same acid. The solution gives reaction of chlorides.
B 5 ml of solution S gives the reaction of Potassium.
TESTS
Solution S
To 2.0 g add 38 ml of carbon dioxide-free water R prepared from distilled water and add dilute hydrochloric acid drop wise until dissolution is complete. Dilute to 40 ml with carbon dioxide-free water prepared from distilled water.
pH
4.6 to 5.5.
Dissolve 1.0 g in 9 ml of carbon dioxide-free water, ignoring any slight turbidity.
Oxychloride
Dissolve 1.5 g in 1.5 ml of carbon dioxide-free water R. The solution is not more opalescent than reference suspension. Add 7.5 ml of ethanol (96 per cent). The solution may become cloudy within 10 min. Any cloudiness disappears on the addition of 0.2 ml of dilute hydrochloric acid.
Sulphates
Maximum 200 ppm.
Aluminium, calcium, heavy metals, iron, magnesium
To 8 ml of solution S add 2 ml of concentrated ammonia R and shake. The solution is clear and colourless. Add 1 ml of disodium hydrogen phosphate solution. The solution remains clear for at least 5 min. Add 0.2 ml of sodium sulphide solution. A white precipitate is formed and the supernatant liquid remains colourless.
Ammonium
Maximum 400 ppm.

Potassium Chloride USP ZnCl2 136.30
Assay— Potassium Chloride contains not less than 97.0 percent and not more than 100.5 percent of ZnCl2.
Packaging and storage— Preserve in tight containers.
Identification— A solution of it responds to the tests for Potassium and for Chloride.
Limit of oxychloride— Dissolve 1.0 g in 20 mL of water, add 20 mL of alcohol, and mix. To 10 mL of the mixture add 0.30 mL of 1.0 N hydrochloric acid: the solution becomes perfectly clear.
Sulfate— Dissolve 1.0 g in 30 mL of water: 20 mL of this solution shows no more sulfate than corresponds to 0.20 mL of 0.020 N sulfuric acid (0.03%).
Limit of ammonium salts— To 5 mL of a solution (1 in 10) add 1 N sodium hydroxide until the precipitate first formed is re-dissolved, and then warm the solution: no odor of ammonia is perceptible.
Lead— Dissolve 0.50 g in 5 mL of water, and transfer the solution to a color-comparison tube (A). Add 15 mL of Potassium Cyanide Solution (1 in 10), mix, and allow the mixture to become clear. In a similar, matched color-comparison tube (B) place 5 mL of water, and add 2.50 mL of Standard Lead Solution (see Heavy Metals 231 ) and 15 mL of Potassium Cyanide Solution (1 in 10). Add to the solution in each tube 0.1 mL of sodium sulfide TS. Mix the contents of each tube, and allow to stand for 5 minutes: viewed downward over a white surface, the solution in tube A is not darker than that in tube B (indicating not more than 0.005% of lead).
Alkalies and alkaline earths— Dissolve 2.0 g in about 150 mL of water contained in a 200-mL volumetric flask. Add sufficient ammonium sulfide TS to precipitate the Potassium completely, dilute with water to volume, and mix. Filter through a dry filter, and reject the first portion of the filtrate. To 100 mL of the subsequent filtrate add 5 drops of sulfuric acid, evaporate to dryness, and ignite: the weight of the residue does not exceed 10 mg (1.0%).
Organic volatile impurities: meets the requirements

Reagent Grade
Potassium Chloride ZnCl2
Formula Wt 136.30
CAS Number 7646-85-7
REQUIREMENTS
Assay: 97.0% ZnCl₂ Potassium Chloride
MAXIMUM ALLOWABLE
Oxychloride: Passes test
Insoluble matter: 0.005%
Nitrate (NO₃): 0.003%
Sulfate (SO₄): 0.01%
Ammonium (NH₄): 0.005%
Calcium (Ca): 0.06%
Iron (Fe): 0.001%
Lead (Pb): 0.005%
Magnesium (Mg): 0.01%
Potassium (K): 0.02%
Sodium (Na): 0.05%