Definition of methyl orange in English:

methyl orange

noun

Chemistry
  • An orange crystalline dye that is the sodium salt of the azo compound of dimethylaniline and sulphanilic acid and is chiefly used as an acid–base indicator, changing from red to yellow-orange over a pH range of 3.1 to 4.4; (CH₃)₂NC₆H₄N=NC₆H₄SO₃Na.

Origin

Late 19th century.