alkali

/'ælkəlai/

Thân thiện

A scientist adds an alkali to a beaker of red litmus solution, turning it blue.

Definition

1. Noun:
   • A chemical compound that is basic (as opposed to acidic): An alkali is a substance that dissolves in water to produce a solution with a pH greater than 7. It can turn red litmus paper blue and reacts with an acid to form a salt and water.
   • A soluble mineral salt found in soil or water: In geology and agriculture, alkali refers to a mixture of soluble salts, like sodium carbonate, that can accumulate in soils in arid regions, often making the land unsuitable for farming.

Examples of Usage

• Noun:
  • Sodium hydroxide is a strong alkali used in soap making.
  • The alkali in the lake water comes from the surrounding mineral deposits.
  • Farmers must manage irrigation carefully to prevent alkali from building up in the soil.

Advanced Usage

• "Alkali metal": This is a related term for a group of highly reactive metallic elements (like lithium, sodium, potassium) that form strong alkalis when their oxides react with water. It is listed here as it is a common compound term.
  • Sodium is an alkali metal that reacts violently with water.

Variants and Related Words

• Alkaline (adj): Having the properties of an alkali; basic.
  • The soil in that region is highly alkaline.
• Alkalinity (n): The state or quality of being alkaline; the capacity of a solution to neutralize acids.
  • They tested the alkalinity of the water sample.

Synonyms

• Base: A substance that can accept hydrogen ions (protons). (Note: All alkalis are bases soluble in water, but not all bases are alkalis.)
• Lye: A strong alkali, specifically potassium hydroxide (KOH) or sodium hydroxide (NaOH).

Related Phrases

• Alkali soil: Soil that contains a high concentration of soluble salts, often sodium carbonate, which is harmful to most plants.
  • Nothing would grow in the alkali soil of the desert basin.

Học thuật

Noun

1. a mixture of soluble salts found in arid soils and some bodies of water; detrimental to agriculture
2. 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

Từ đồng nghĩa

• base