METHYL ORANGE • FREE TRANSLATOR.ORG • Definition of Methyl orange

... Mandarin orange), (CH3)2N.C6H4.N2.C6H4SO3Na, is the sodium salt of para-dimethylaminobenzene-azo-benzene sulphonic acid. It is an orange crystalline powder which is soluble in water, forming a yellow solution. The free acid is intensely red in colour. Methyl orange is used largely as an indicator. The constitution of methyl orange follows from the fact that on reduction by stannous chloride in hydrochloric acid solution it yields sulphanilic acid ...

— Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 - "Austria, Lower" to "Bacon" • Various