alkali

American  

[al-kuh-lahy] / ˈæl kəˌlaɪ /

noun

• alkalis,
  plural
• alkalies
  plural

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.

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adjective

1. Chemistry. alkaline.

alkali British  

/ 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

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alkali Scientific  

/ ăl′kə-lī′ /

• alkalis
  plural

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

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alkali Cultural  

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

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Discover More

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

Other Word Forms

Noun Inflected Forms

• alkalies
  plural
• alkalis
  plural

Etymology

Origin of alkali

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

Example Sentences

See Examples For:

alkali alkalies alkalis

She remembers the lake being much higher in her youth when she went to the shore with her family, carrying baskets to collect kootzabe, or alkali fly pupae, a traditional food source.

From Los Angeles Times ● Aug. 4, 2025

The low-carbon seawater then has alkali added to it – to neutralise the acid that was added – and is then pumped back out into a stream that flows into the sea.

From BBC ● Apr. 17, 2025

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 ● Sep. 21, 2024

Because a vanadium peroxide molecule is negatively charged, it needed alkali cations for charge balance, Nyman said, and the researchers used potassium, rubidium and cesium alkali cations for this study.

From Science Daily ● Feb. 12, 2024

He drifted past saguaros and alkali flats, camped beneath escarpments of naked Precambrian stone.

From "Into the Wild" by Jon Krakauer

Pots, pans, vats, machines exposed to corrosives will be protected by a skin of aluminum, metal highly resistant to mos.t acids and alkalies.

From Time Magazine Archive

The discovery of electrolytic hypochlorites dates back to 1859, when Watt found that chlorides of the fixed alkalies and alkaline earths yielded hypochlorites on being submitted to the action of an electrical current.

From Chlorination of Water by Joseph Race

They make it clear that there has been an introduction of fluorine and boron and a diminution in the alkalies during the transformation of the granitic rock into the greisen.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 5 "Greek Law" to "Ground-Squirrel" by Various

He deals with human character as a chemist with his acids and alkalies, and while he mixes his coloured fluids in a way that surprises the profane, knows perfectly well what he is about.

From Views and Reviews by Henry James

Of or pertaining to an alkali or to alkalies; having the properties of an alkali. ÷ earths, certain substances, as lime, baryta, strontia, and magnesia, possessing some of the qualities of alkalies.

From Webster's Unabridged Dictionary by Noah Webster

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

From Science Daily ● Feb. 12, 2024

Fermenting encompasses a range of processes through which microorganisms — yeasts, molds, bacteria — break down compounds in food to create alcohols, acids or alkalis, which in turn prevent the growth of harmful pathogens.

From Salon ● Dec. 6, 2023

Coal provided the power; the nascent chemical industry supplied the acids and alkalis essential to these enterprises.

From Nature ● Aug. 30, 2020

Alkalis were extracted from ashes, and soaps were prepared by combining these alkalis with fats.

From Textbooks ● Feb. 14, 2019

However polluted the former of these may be, still the vast advance which it made by the discovery of the principal acids, alkalis, and the more common of their salts, should be constantly recognized.

From De Re Metallica, Translated from the First Latin Edition of 1556 by Georgius Agricola