Definition of alkali in English:

alkali

noun

  • A chemical compound that neutralizes or effervesces with acids and turns litmus blue; typically, a caustic or corrosive substance of this kind such as lime or soda.

    Often contrasted with acid; compare with base
    • ‘Soap is made by combining a fat source (either animal or vegetable) and an alkali in a chemical process known as saponification.’
    • ‘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…’
    • ‘It combines with most non-metals at high temperatures and reacts with both acids and alkalis.’
    • ‘It can withstand high temperatures and is resistant to many corrosive substances such as acids and alkalis.’
    • ‘Caustic alkalis react with the paint coating and loosen it from the surface.’
    • ‘Carboxylic acids also react with alkalis, or bases.’
    • ‘Tellurium reacts with both acids and some alkalis.’
    • ‘Copper is a moderately reactive metal that dissolves in most acids and alkalis.’
    • ‘Amides are hydrolysed to ammonium salts with catalysis by acids or alkalis.’
    • ‘It accounted for acids and alkalis, for respiration and the smells of plants.’
    • ‘Concentrated acids and caustic alkalis should be handled with the greatest care.’
    • ‘Chemically, aluminum will react with the alkalis in concrete and produce hydrogen bubbles.’
    • ‘They resist most chemicals, including many acids, alkalis, oxidizing agents, and solvents.’
    • ‘Nitriles can be decomposed by acids or alkalis to give the corresponding carboxylic acid or they can be reduced to give primary amines.’
    • ‘The high-density overlay protects the wood substrate from alkalis and water.’
    • ‘Platinum also dissolves in hot alkalis such as hot sodium hydroxide or potassium hydroxide.’
    • ‘Corrosives (mineral acids, alkalis, phenols) are in this category.’
    • ‘Like semi-permanent dyes, permanent dyes are also alkalis.’
    • ‘Zinc is a fairly active metal that dissolves in both acids and strong alkalis.’
    • ‘On contact, strong acids, alkalis, and heavy metals cause chemical burns.’
    caustic, corroding, eroding, erosive, abrasive, biting, mordant, burning, stinging
    View synonyms

Origin

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

Pronunciation:

alkali

/ˈalkəˌlī/