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

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

A man suspected of an alkali attack in south London should not have been granted asylum, according to Home Office guidelines.

From BBC ● Feb. 2, 2024

Experiments of the German Gerhard Schramm, first published in 1944, reported that TMV particles in mild alkali fell apart into free RNA and a large number of similar, if not identical, protein molecules.

From "Double Helix" by James D. Watson

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

Graphite is not affected by heat, cold, acids, or alkalies, and has a strong attraction for metal surfaces.

From Aviation Engines Design?Construction?Operation and Repair by Victor Wilfred Pag?

As the process of ripening becomes perfected, the acids combine with alkalies, and thus the acidity of the fruit diminishes, while its sweetness increases.

From American Pomology Apples by J. A. Warder

Alkalies also combine with oils, and the less thin and volatile they are, the more easily are they soluble in alkalies.

From Heads of Lectures on a Course of Experimental Philosophy: Particularly Including Chemistry by Joseph Priestley

Acids and alkalies are to some extent responsible for the fading of fabrics in the wash when these fabrics owe their colour to vegetable dyes.

From Household Administration Its Place in the Higher Education of Women by Various

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

E Earths, 177; Stahl's views, 178; the connection between earths and alkalis, 178; their metallic bases, 182, 200.

From Heroes of Science Chemists by M. M. Pattison (Matthew Moncrieff Pattison) Muir