Alkalischen

Alkalisch (alkaline) refers to substances or solutions that exhibit basic properties, typically raising the pH above 7 when dissolved in water. In chemistry, alkaline substances are bases that can neutralize acids and often form hydroxide ions in aqueous solutions. The term is commonly used to distinguish soluble bases, or alkalis, from more insoluble basic oxides or salts.

There are several definitions of bases. The Arrhenius definition says bases produce hydroxide ions (OH−) in water. The Brønsted–Lowry framework defines bases as substances that accept protons. Alkalinity also encompasses the buffering capacity of water, which is the ability to neutralize added acids; this capacity mainly arises from bicarbonate, carbonate, and, to a lesser extent, hydroxide ions in solution. Alkaline earth metals and alkali metals form basic oxides that react with water to yield basic solutions.

Common examples of alkaline substances include sodium hydroxide (lye), potassium hydroxide, ammonium hydroxide (ammonia in water), and sodium carbonate. In everyday use, the term “alkalis” often refers to water-soluble bases that markedly increase pH. Alkaline materials have broad applications in industry and daily life, such as in cleaning agents, pulp and paper production, water treatment, and food processing (for example, baking practices that involve alkaline additives).

Natural environments can be alkaline as well. Alkaline soils have pH above 7 and can affect plant availability of nutrients. Some lakes and mineral waters exhibit alkalinity due to dissolved carbonate or bicarbonate ions. Handling alkaline substances requires caution: they are caustic and can cause chemical burns; protective equipment is advised, and mixing with acids can release heat and gases.