alkali

[al-kuh-lahy]

noun

plural

alkalis, alkalies 

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

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.

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

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

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

This process combines fats or oils with an alkali to produce soap.

From BBC

The company has one aquamation machine that uses alkali solution, heat and pressure to break down the organic material into ashes.

From Los Angeles Times

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