alkali

/ˈælkəlaɪ/ (bre, ipa) · /ˈælkəlaɪ/ (ame, ipa) · /ˈal-kə-ˌlī/ (ame, mw)

alkali — noun

  • alkalisingular
  • alkaliesplural

1. a basic chemical that can cancel out an acid and leaves water above pH 7

1.名詞C1
釋義

a basic chemical that can cancel out an acid and leaves water above pH 7

例句

Jiwoo used litmus paper to check whether the cleaner contained alkali.

alkali in household cleaner

After the leak, alkali was poured onto the floor to stop the acid.

passive: alkali was poured

同義詞
  • base

    broader chemistry term; some bases are not soluble in water and are not called alkalis

  • lye

    much narrower everyday term for a strong caustic alkali such as sodium hydroxide

  • alkaline substance

    descriptive phrase rather than a fixed technical noun

反義詞
  • acid

    opposite side of the acid-base scale

文法句型

an alkali

strong / weak alkali

alkali in solution

用法筆記

Mostly used in chemistry, cleaning, and manufacturing. Compared with the broader word 'base', 'alkali' usually refers to a base that dissolves in water and makes an alkaline solution.

常見錯誤

❌All bases are alkalis.
✅All alkalis are bases, but some bases are not alkalis.
💡An alkali is a water-soluble kind of base, so the two words are not fully interchangeable.

2. harmful soluble salts in dry soil that make farming difficult

2.名詞C2
釋義

harmful soluble salts in dry soil that make farming difficult

例句

After years without rain, alkali spread across the field in white patches.

white patches in dry fields

The farmer planted barley because the soil's alkali killed the tomato crop.

同義詞
  • salt build-up

    plain-language description of what happens in the soil, rather than a technical noun

  • saline soil

    related farming term that focuses on the condition of the land rather than the salt material itself

文法句型

alkali in the soil

wash out alkali

high alkali levels

用法筆記

Used mainly in farming and soil science. In this sense, the word refers to the harmful salt problem in the ground, not to a lab chemical kept in a bottle.

常見錯誤

❌The scientist kept the alkali in a glass bottle.
✅The farmer found alkali in the dry soil.
💡In this sense, alkali means harmful salts in the land, not a chemical sample in a container.