alkali

[ al-kuh-lahy ]

noun

, plural al·ka·lis, al·ka·lies.

1. Chemistry.
   1. any of various bases, the hydroxides of the alkali metals and of ammonium, that neutralize acids to form salts and turn red litmus paper blue.
   2. any of various other more or less active bases, as calcium hydroxide.
   3. (not in technical use) an alkali metal.
   4. Obsolete. any of various other compounds, as the carbonates of sodium and potassium.
2. Agriculture. a soluble mineral salt or a mixture of soluble salts, present in some soils, especially in arid regions, and detrimental to the growing of most crops.

adjective

1. Chemistry. alkaline.

alkali

/ ˈælkəˌlaɪ /

noun

1. chem a soluble base or a solution of a base
2. a soluble mineral salt that occurs in arid soils and some natural waters

alkali

/ ăl′kə-lī′ /

, Plural alkalis

1. A hydroxide of an alkali metal. The aqueous solution of alkalis is bitter, slippery, caustic, and characteristically basic in reactions.

alkali

1. A bitter, caustic mineral often found in large beds in the desert. Alkalis are bases ; two common examples are lye and ammonia.

Notes

Plants have difficulty growing in soil that is rich in alkalis.

Word History and Origins

Origin of alkali¹

1300–50; Middle English alkaly < Middle French alcali < dialectal Arabic al-qalī, variant of Arabic qily saltwort ashes

Word History and Origins

Origin of alkali¹

C14: from Medieval Latin, from Arabic al-qili the ashes (of the plant saltwort)

Example Sentences

Another Los Angeles Times report on a roundup of immigrants begins by noting, “Human misery was compounded here today by a blistering desert sun and swirls of alkali dust.”

From Salon

Using the proposed method, larger alkali metal ions such as cesium could be incorporated into the perovskite structure, leading to ferroelectrics with desirable dielectric properties.

From Science Daily

The magenta pigments developed by OSU researchers are thermally and chemically inert because of their high preparation temperature and remain unaltered structurally and optically upon exposure to acid and alkali, the authors note.

From Science Daily

In addition, the scientists substituted ammonium and tetramethyl ammonium, the former of which is mildly acidic, for the alkalis.

From Science Daily

Ezedi has not been seen since the night of the attack on 31 January, when an alkali substance was thrown over a mother and her two children.

From BBC