Adjacent Words

Alkali definitions

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Webster's 1828 Dictionary

AL'KALI, n. plu. Alkalies
In chimistry, a term applied to all bodies which possess the following properties:
1. a caustic taste;
2. volatilizable by heat;
3. capability of combining with acids, and of destroying their acidity;
4. solubility in water, even when combined with carbonic acid;
5. capability of converting vegetable blues to green.
The term was formerly confined to three substances:
1. potash or vegetable fixed alkali, generally obtained from the ashes of wood;
2. soda or mineral fixed alkali, which is found in the earth and procured from marine plants; and
3. ammonia or volatile alkali, an animal product.
Modern chimistry has discovered many new substances to which the term is now extended.
The alkalies were formerly considered as elementary substances; but it is now ascertained that they are all compounds.
The alkalies are used in the manufacture of glass and soap, in bleaching and in medicine.

WordNet (r) 3.0 (2005)

n
1: 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" [syn: base, alkali]
2: a mixture of soluble salts found in arid soils and some bodies of water; detrimental to agriculture

Merriam Webster's

noun (plural -lies or -lis) Etymology: Middle English, from Medieval Latin, from Arabic al-qili the ashes of the plant saltwort Date: 14th century 1. a soluble salt obtained from the ashes of plants and consisting largely of potassium or sodium carbonate; broadly a substance (as a hydroxide or carbonate of an alkali metal) having marked basic properties — compare base 7a 2. alkali metal 3. a soluble salt or a mixture of soluble salts present in some soils of arid regions in quantity detrimental to agriculture

Oxford Reference Dictionary

n. (pl. alkalis) 1 a any of a class of substances that liberate hydroxide ions in water, usu. form caustic or corrosive solutions, turn litmus blue, and have a pH of more than 7, e.g. caustic soda. b any other substance with similar but weaker properties, e.g. sodium carbonate. 2 Chem. any substance that reacts with or neutralizes hydrogen ions. Phrases and idioms: alkali metals any of the univalent group of metals, lithium, sodium, potassium, rubidium, and caesium, whose hydroxides are alkalis. Derivatives: alkalimeter n. alkalimetry n. Etymology: ME f. med.L, f. Arab. al-kali calcined ashes f. kala fry

Webster's 1913 Dictionary

Alkali Al"ka*li, n. Soluble mineral matter, other than common salt, contained in soils of natural waters. [Western U. S.]

Webster's 1913 Dictionary

Alkali Al"ka*li (?; 277), n.; pl. Alkalis or Alkalies. [F. alcali, ultimately fr. Ar. alqal[=i] ashes of the plant saltwort, fr. qalay to roast in a pan, fry.] 1. Soda ash; caustic soda, caustic potash, etc. 2. (Chem.) One of a class of caustic bases, such as 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. Fixed alkalies, potash and soda. Vegetable alkalies. Same as Alkaloids. Volatile alkali, ammonia, so called in distinction from the fixed alkalies.

Collin's Cobuild Dictionary

(alkalis) An alkali is a substance with a pH value of more than 7. Alkalis form chemical salts when they are combined with acids. ? acid N-MASS

Moby Thesaurus

acid, acidity, agent, alkalinity, alloisomer, anion, antacid, atom, base, biochemical, cation, chemical, chemical element, chromoisomer, compound, copolymer, dimer, element, heavy chemicals, high polymer, homopolymer, hydracid, inorganic chemical, ion, isomer, macromolecule, metamer, molecule, monomer, neutralizer, nonacid, organic chemical, oxyacid, polymer, pseudoisomer, radical, reagent, sulfacid, trimer