Meaning of ALKALI in English

ALKALI

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

Oxford English vocab.      Оксфордский английский словарь.