Potassium hydroxide in the context of "Bredig's arc method"

Potash (/ˈpɒtæʃ/ POT-ash) are mined and manufactured salts that contain potassium in water-soluble form. The term potash derives from pot ash, either plant ashes or wood ashes that were soaked in water in a pot, which was the primary means of manufacturing potash before the Industrial Era; the word potassium derives from the term potash.

In 2021, the worldwide production of potash exceeded 71.9 million tonnes (~45.4 million tonnes K₂O equivalent), and Canada is the greatest producer of potash as fertilizer. Potassium was first derived in 1807 by electrolysis of caustic potash (potassium hydroxide).

In chemistry, there are three definitions in common use of the word "base": Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century.

In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form hydroxide ions OH. These ions can react with hydrogen ions (H according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction. A base was therefore a metal hydroxide such as NaOH or Ca(OH)₂. Such aqueous hydroxide solutions were also described by certain characteristic properties. They are slippery to the touch, can taste bitter and change the color of pH indicators (e.g., turn red litmus paper blue).

Potassium peroxide is an inorganic compound with the molecular formula K₂O₂. It is formed as potassium reacts with oxygen in the air, along with potassium oxide (K₂O) and potassium superoxide (KO₂).

Potassium peroxide reacts with water to form potassium hydroxide and oxygen:

Lye is the common name of various alkaline solutions, including soda lye (a solution of sodium hydroxide) and potash lye (a solution of potassium hydroxide). Lyes are used as cleaning products, as ingredients in soapmaking, and in various other contexts.

An alkaline battery (IEC code: L) is a type of primary battery where the electrolyte (most commonly potassium hydroxide) has a pH value above 7. Typically, these batteries derive energy from the reaction between zinc metal and manganese dioxide.

Compared with zinc–carbon batteries, alkaline batteries have a higher energy density and longer shelf life yet provide the same voltage.

Potassium iodide is a chemical compound, medication, and dietary supplement. It is a medication used for treating hyperthyroidism, in radiation emergencies, and for protecting the thyroid gland when certain types of radiopharmaceuticals are used. It is also used for treating skin sporotrichosis and phycomycosis. It is a supplement used by people with low dietary intake of iodine. It is administered orally.

Common side effects include vomiting, diarrhea, abdominal pain, rash, and swelling of the salivary glands. Other side effects include allergic reactions, headache, goitre, and depression. While use during pregnancy may harm the baby, its use is still recommended in radiation emergencies. Potassium iodide has the chemical formula KI. Commercially it is made by mixing potassium hydroxide with iodine.

Potassium hydrosulfide is an inorganic compound with the formula KSH. This colourless salt consists of the cation K and the bisulfide anion [SH]. It is the product of the half-neutralization of hydrogen sulfide with potassium hydroxide. The compound has been used in the synthesis of organosulfur compounds. Aqueous solutions of potassium sulfide consist of a mixture of potassium hydrosulfide and potassium hydroxide.

The structure of the potassium hydrosulfide resembles that of potassium chloride. Their structure is however complicated by the non-spherical symmetry of the SH anions, but these tumble rapidly in the solid.

A UN number (United Nations number) is a four-digit number that identifies hazardous materials, and articles (such as explosives, flammable liquids, oxidizers, toxic liquids, etc.) in the framework of international trade and transport. Some hazardous substances have their own UN numbers (e.g. acrylamide has UN 2074), while sometimes groups of chemicals or products with similar properties receive a common UN number (e.g. flammable liquids, not otherwise specified, have UN 1993). A chemical in its solid state may receive a different UN number than the liquid phase if its hazardous properties differ significantly; substances with different levels of purity (or concentration in solution) may also receive different UN number