Potassium hydroxide is a chemical composed of one atom each of potassium, oxygen and hydrogen. It's chemical formula is KOH. It played a crucial role in the identification of a metallic element, and continues to be important today in research science, medicine, household cleaners and several industrial processes.
History
According to Potassiumhydroxide.com, potassium hydroxide's other name, potash, is an English word derived from the fact that it could be found in pots where plant material had been burned to ash, hence "pot-ash." Knowledge of potassium hydroxide led directly to the discovery of the element potassium by Sir Humphry Davy in 1807. He heated the material, then used electrolysis to separate the potassium atoms from the hydroxide groups. It is no coincidence that potassium and potash begin with the same five letters: The elemental metal was named after the material from which it was isolated.
Physical Properties
Pure potassium hydroxide usually exists as solid pellets. These pellets are white and odorless. They melt at 716 degrees Fahrenheit and completely decompose at 2,523 degrees Fahrenheit. With a specific gravity of 2.044, potassium hydroxide is essentially twice as dense as water and will thus sink in liquid as it dissolves.
Chemical Properties
Solid potassium hydroxide is stable at room temperature but can react with moist air. It dissolves extremely well in water, and the resulting solution can be very caustic--a 1 percent solution has a pH of 13 and the pH scale only goes up to 14. Dissolving potassium hydroxide in water results in significant heat generation. Pure potassium hydroxide and potassium hydroxide solutions will react violently with acids and other solutions with low pHs. Some metals, such as aluminum, brass and zinc, will be corroded by potassium hydroxide. The chemical does not affect stainless steel.
Uses
Potassium hydroxide has several industrial uses. Farmers use it to adjust soil pH and kill fungi and weeds. Chemical manufacturers use it as an ingredient in soap-making, to defoam paper as its made, to control the pH of primary reactions and as an ingredient in certain acrylate coatings. In medicine, potassium hydroxide can indicate fungal infections and dissolve warts. It is also present in some common home cleaning agents and drain-clearing chemicals. Finally and perhaps most importantly, potassium hydroxide is one of the most common electrolytes in the batteries used to power things like flashlights and calculators.
Safety Considerations
According to potassium hydroxide's material safety data sheet, you should take into account several safety considerations when handling the chemical. Essentially, potassium hydroxide destroys human tissue. Some common routes of hazardous exposure include absorption through the skin, inhalation of pellet dust and ingestion of pellets or solutions. Inhalation will result in lung damage, ingestion will result in damage to the esophagus and stomach and skin exposure can result in severe corrosive burns. Additionally, contact with the eyes may cause irreversible blindness. As such, you should wear protective clothing including full lab coats, goggles and gloves when handling potassium hydroxide.
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