Which of the following is not a chromophore?

Options

A. `-N=N-`
B. `-NO`
C. `-NO_2`
D. `-NH_2`

Answer

D

Explanation

A dye molecule is made up of two different parts (i) Chromophore (ii) Auxochrome. The groups which produce colour in a compound i.e., chromophores are usual unsaturated groups like nitro, nitroso, azo, azoxy, carbonyl and olefinic bonds Auxochrome are usually acidic / basic functional group like -OH, -COOH, `-SO_3 H, -NH_2, -NHR, -NR_2` .
A compound containing only a chromophore may be coloured material but not a dye. For example azo benzene is red coloured but not a dye. Where as para amino azobenzene (aniline yellow) is a dye.