Potassium chloride (KCl) is a common chemical compound that comes in several grades, one of which is pure grade. Pure-grade potassium chloride is typically used in high-precision applications, such as in laboratory settings, manufacturing, or pharmaceutical industries. It is a crystalline salt and consists of potassium (K) and chloride (Cl) ions.

Potassium benzoate (E212), the potassium salt of benzoic acid, is a food preservative that inhibits the growth of mold, yeast and some bacteria. It works best in low-pH products, below 4.5, where it exists as benzoic acid.

Acidic foods and beverages such as fruit juice (citric acid), sparkling drinks (carbonic acid), soft drinks (phosphoric acid), and pickles (vinegar) may be preserved with potassium benzoate. It is approved for use in most countries including Canada, the United States and the European Union, where it is designated by the E number E212.

Potassium benzoate is also used in the whistle in many fireworks.