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

And he has seen them descend on Mono Lake when the water is teeming with brine shrimp and the larvae and pupae of alkali flies.

From Los Angeles Times ● Aug. 22, 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

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 ● Apr. 25, 2024

The BBC's Mark Easton has been asking Commander Jon Savell about why it's taking time to find the alleged Clapham alkali attacker.

From BBC ● Feb. 5, 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

Like all resins, these are insoluble in water, soluble in alkalies, but precipitated on neutralization of the alkaline solution.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 6 "Groups, Theory of" to "Gwyniad" by Various

In the same manner, alkalies may be detected by a strip of turmeric yellow paper, which will be also changed to red by alkalies.

From A Select Collection of Valuable and Curious Arts and Interesting Experiments, Which are Well Explained and Warranted Genuine and may be Performed Easily, Safely, and at Little Expense. by Various Unknown

The best antidotes for acids are soda, lime-water, soap-suds, and chalk; for alkalies, weak acids, such as lemons, oranges, vinegar, or cider.

From How to Care for the Insane A Manual for Nurses by William D. Granger

Hydrolysis is reduced by caustic alkalies and alkaline carbonates, and increased by acids and acid carbonates that reduce the OH′ concentration.

From Chlorination of Water by Joseph Race

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

A solution of caustic potash or soda forms with gentianin a yellow solution, and the tincture of the root to which either of these alkalis has been added loses its bitterness in a few days.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" by Various