Definition of alkali in English:

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Pronunciation: /ˈalkəlʌɪ/

noun (plural alkalis)

1A compound with particular chemical properties including turning litmus blue and neutralizing or effervescing with acids; typically, a caustic or corrosive substance of this kind such as lime or soda: flint is not subject to chemical weathering except by strong alkalis [mass noun]: the reaction is followed by measuring the concentration of alkali at various times Often contrasted with acid and base1.
More example sentences
  • Amides are hydrolysed to ammonium salts with catalysis by acids or alkalis.
  • They resist most chemicals, including many acids, alkalis, oxidizing agents, and solvents.
  • Nickel has good resistance to corrosion in the normal atmosphere, in natural freshwaters and in deaerated nonoxidizing acids, and it has excellent resistance to corrosion by caustic alkalis…
1.1 [as modifier] chiefly North American Alkaline.
Example sentences
  • A vast white alkali flat unrolled across the field of his dream, ringed with serrated purple mountains at the horizon.
  • Additionally, clinically, if CO2 tensions venture into the range of 80-100 mm Hg in critically patients, the use of alkali therapy is generally mandatory.
  • For the first few days, the country presented picturesque timbered bottomlands and rolling prairie, but slowly it changed to a rocky landscape littered with buffalo bones and stagnant pools of undrinkable alkali water.

Alkalis release hydroxide ions (OH) when dissolved in water. Any solution with a pH of more than 7 is alkaline



Pronunciation: /alkəˈlɪmɪtə/


Pronunciation: /alkəˈlɪmɪtri/


Late Middle English (denoting a saline substance derived from the ashes of various plants, including glasswort): from medieval Latin, from Arabic al-qalī 'calcined ashes (of the glasswort etc.)', from qalā 'fry, roast'.

  • The chemistry term alkali is from medieval Latin, from Arabic al-kalī ‘calcined ashes’ referring to the plants from which alkalis were made. Early 19th-century alkaloid (a class of compounds including morphine, quinine, and strychnine) was coined in German from alkali.

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