noun (plural alkalis)
- a compound with particular chemical properties including turning litmus blue and neutralizing or effervescing with acids; typically, a caustic or corrosive substance of this kind such as lime or soda: flint is not subject to chemical weathering except by strong alkalis [mass noun]:the reaction is followed by measuring the concentration of alkali at various timesOften contrasted with acid and base1.
Alkalis release hydroxide ions (OH−) when dissolved in water. Any solution with a pH of more than 7 is alkaline
late Middle English (denoting a saline substance derived from the ashes of various plants, including glasswort): from medieval Latin, from Arabic al-qalī 'calcined ashes (of the glasswort etc.)', from qalā 'fry, roast'
Make the plural in the usual way, by adding s: (alkalis).