Witt’s Theory of color constitution
Witt’s theory of color constitution establish in 1876. Witt argue a theory per that the colour of a substance is principally attributable to the presence of associate unsaturated cluster referred to as Chromophores (Greek chroma‐color, and phores‐bearing). The necessary chromophores are
- First ‐C = C
- second ‐C = N
- ‐C = O
- ‐N = N
The compounds possessing chromophoresare referred to as chromogens. The chromophericgroups ar of the subsequent 2 sorts.
When one chromophoreis decent to impart color to the compound. Examples are, ‐NO, NO2, ‐N=N, =N=N‐N, ‐N=N→O, p‐quinonoidetc.
When over one chromophoreis needed to impart the colour this could be exemplified by varied examples , Acetone (having one >C=O as chromophore) is colorless, whereas biacetyl(with two >C=O) is yellow
How Does Witt’s theory Work
Since the auxochromesare capable of forming salts either with a basic or acidic teams their presence additionally convert a coloured compound (devoid of salt forming groups) into a dye that should fix for good to the fiber, i.e., it should be quick to water, light, soap and lavation, once mounted to the fiber. The permanent fixing of dye to the fiber is usually attributable to the formation of attractive force between the fiber and also the auxochrome. this could best be exemplified by the subsequent examples