Knowra Alkali Alkali An alkali is a water-soluble base that produces hydroxide ions in solution or neutralizes acids. Alkalis include soluble metal hydroxides and some other basic substances.
Arrhenius base : A substance that increases hydroxide-ion concentration when dissolved in water. This definition describes how many alkalis create their characteristic hydroxide ions.
Base (chemistry) : A substance that accepts protons, donates electron pairs, or increases hydroxide-ion concentration, depending on the definition used. Alkalis are the water-soluble members of the broader class of bases.
Sodium hydroxide : A strongly caustic ionic compound, NaOH, that dissolves readily in water. This widely used alkali makes soap, paper, and many industrial chemicals.
Acid–base indicator : A substance that changes color over a range of acidity or alkalinity. Indicators reveal an alkali’s pH but are not themselves necessarily alkaline.
Brønsted–Lowry base : A species that accepts a proton from another species. Alkalis neutralize acids by accepting protons, a broader account than hydroxide release alone.
Hydroxide ion : A negatively charged ion consisting of one oxygen atom and one hydrogen atom. Hydroxide ions account for the characteristic basic behavior of many dissolved alkalis.
Potassium hydroxide : A caustic, water-soluble ionic compound with formula KOH. It is an alkali used in liquid soap, batteries, and chemical manufacturing.
Alkalinity : The capacity of water to neutralize added acid, chiefly through dissolved bases and related ions. Alkali names a substance; alkalinity measures a solution’s acid-neutralizing capacity.
pH : A logarithmic measure of hydrogen-ion activity in a solution. Dissolved alkalis generally raise solution pH by reducing hydrogen-ion activity.
Water : A polar molecular liquid composed of hydrogen and oxygen with formula H₂O. Water dissolves alkalis and provides the medium in which their ions act.
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