ALKALI

base, alkali

(noun) any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water; “bases include oxides and hydroxides of metals and ammonia”

alkali

(noun) a mixture of soluble salts found in arid soils and some bodies of water; detrimental to agriculture

Source: WordNet® 3.1

Etymology

Noun

alkali (countable and uncountable, plural alkalis or alkalies)

(chemistry) One of a class of caustic bases, such as soda, soda ash, caustic soda, potash, ammonia, and lithia, whose distinguishing peculiarities are solubility in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, turning to brown several vegetable yellows, and changing reddened litmus to blue.

(Western United States) Soluble mineral matter, other than common salt, contained in soils of natural waters.

Synonyms

• (chemistry): base

Antonyms

• (chemistry): acid

Source: Wiktionary

Al"ka*li, n.; pl. Alkalis or Alkalies. Etym: [F. alcali, ultimately fr. Ar. alqali ashes of the plant saltwort, fr. qalay to roast in a pan, fry.]

1. Soda ash; caustic soda, caustic potash, etc.

2. (Chem.)

Definition: One of a class of caustic bases, such as soda, potash, ammoma, and lithia, whose distinguishing peculiarities are solubility in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, turning to brown several vegetable yellows, and changing reddened litmus to blue. Fixed alkalies, potash and soda.

– Vegetable alkalies. Same as Alkaloids.

– Volatile alkali, ammonia, so called in distinction from the fixed alkalies.

Source: Webster’s Unabridged Dictionary 1913 Edition