In chemistry, an alkali is a basic, ionic salt
of an alkali metal or an alkaline earth metal.
Any chemical species, ionic or molecular, capable of accepting or receiving a proton (hydrogen ion) from another substance; the other substance acts as an acid in giving of the proton.
One of a class of caustic bases, such as soda, soda ash, caustic soda, potash, ammonia, and lithia, whose distinguishing peculiarities are solubility in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, turning to brown several vegetable yellows, and changing reddened litmus to blue.
Any of a class of generally water-soluble compounds, having bitter taste, that turn red litmus blue, and react with acids to form salts.