What is an auxochrome in chemistry?

An auxochrome is a functional group of atoms with one or more lone pairs of electrons when attached to a chromophore, alters both the wavelength and intensity of absorption.

What is an auxochrome and chromophore?

Chromophore is that part of the molecule which when exposed to visible light will absorb and reflect a certain color. Auxochrome is a group of atoms which is functional and has the capability to alter the capacity of the chromophore to reflect colors. Azobenzene is an example of a dye which contains a chromophore.

What do you mean by auxochrome give an example?

Any portion of a molecule, i.e. radical or ionic functional group, that improves the color of the chromophore in an organic colorant. Auxochromes can also provide an ionic site that enables the dye to bind to a fiber. Examples of auxochrome groups are -COOH, -SO3H, -OH, and -NH3.

What is the role of auxochrome?

All auxochromes have one or more non-bonding pairs of electrons. If an auxochromes is attached to a chromophore, it helps is extending the conjugation by sharing of non-bonding pair of electrons as shown below. The extended conjugation has been responsible for bathochromic effect of auxochromes.

What is chromophore chemistry?

Chromophore is an unsaturated group that absorbs light and reflects it at specific angle to give the hue, e.g., azo, keto, nitro, nitroso, thio, ethylene etc; From: Fundamentals and Practices in Colouration of Textiles, 2014.

Who discovered auxochrome?

In 1876, Witt proposed that dye molecules contain two groups; the chromophore and the auxochrome. The chromophore is a group of atoms which control the colour of the dye. At that time, Witt suggested that the auxochrome was a salt-forming group, which helped to improve the colour of the dye.

What is a chromophore in chemistry?

Which is not an auxochrome?

Solution : `gt C = N` is not an auxochrome.

Which group acts as an auxochrome in methyl orange dye?

1. Nitro and Nitroso Dyes: They contain nitro (NO2) or nitroso (N=O) groups in their structure and are generally polynitro derivatives of phenol. They have the nitro group as the chromophore and hydroxyl or amino group as auxochrome.

Is a benzene ring a chromophore?

The Benzene Ring as an Optically Active Chromophore | Journal of the American Chemical Society.

Which one of the following is an auxochrome?

Solution : group like -OH,-COOH,`-SO_(3)H`-,-NHR-, `NR_(2)`,-`NH_(2)` are auxochromic .