alkaal

Alkaal is the Dutch and Afrikaans term for alkali, referring to chemical bases that dissolve in water to form alkaline solutions. In English, the standard term is alkali. In chemistry, alkalis are bases that release hydroxide ions (OH−) in aqueous solution and are described by Arrhenius and Bronsted–Lowry definitions. They typically have a pH greater than 7 and turn blue litmus paper.

Alkalis are usually soluble bases that raise the pH of water. They form hydroxide ions in solution and are often caustic and corrosive to skin and eyes. Many alkalis react exothermically with acids and with organic materials, and they may react with carbon dioxide in the air to form carbonates. Because of their reactivity, handling and storage require appropriate safety precautions.

Common examples include sodium hydroxide (caustic soda) and potassium hydroxide (caustic potash). Calcium hydroxide (slaked lime) is also classified as an alkali, though it is less soluble. Related alkaline substances include sodium carbonate and sodium bicarbonate, which raise pH but are less caustic and are widely used in food, cleaning, and water-treatment applications.

Applications of alkalis span many sectors. They are essential in soap and detergent manufacture, paper production, water treatment, and pH adjustment in agriculture and industry. Baking soda (sodium bicarbonate) and related carbonates are used in cooking and as leavening agents, while stronger alkalis serve in caustic cleaning products and various chemical processes.

Etymology and usage: The word alkali derives from Arabic al-qaly (calcined ashes) through Medieval Latin and French; the Dutch term alkaal shares the same root. In scientific contexts, alkali and base are related concepts, with alkali often referring to water-soluble bases.