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

After spending July gorging on the larvae of alkali flies, the birds are gradually departing this month to begin their migration to another saline lake about 6,000 miles away — Laguna Mar Chiquita in Argentina.

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

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 ● Apr. 16, 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

The way to unlock the niacin in corn is to cook it with an alkali like lime.

From "The Omnivore's Dilemma" by Michael Pollan

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

Second, they must not be easily affected by acids or alkalies; hence, it has been difficult to produce colors that are reasonably permanent and at the same time harmless.

From Frye's Practical Candy Maker Comprising Practical Receipts for the Manufacture of Fine "Hand-Made" Candies by George V. Frye

Lime, and the alkalies, are generally safe and useful additions, in connection with clover as a green manure; these may be applied to almost any worn soils with great advantage.

From American Pomology Apples by J. A. Warder

Strong acids and alkalies act as caustics; that is they destroy fabrics.

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

Turmeric, tur′mėr-ik, n. the rhizome or root-stock of Curcuma longa, a handsome herbaceous plant cultivated all over India, its yellowish tubers yielding a deep-yellow powder used as a chemical test for the presence of alkalies.

From Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements) 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

The differences are surprisingly small and are principally an increase in the water and a diminution in the amount of alkalis and lime together with the oxidation of the ferrous oxide.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" by Various