Question

in aniline,the NH2 group acts as a:
a)auxochrome
b) chromophore​

Answer 1

Explanation:

An auxochrome (from Ancient Greek αὐξάνω auxanō "increase" and χρῶμα chrōma "colour") is a group of atoms attached to a chromophore which modifies the ability of that chromophore to absorb light. They themselves fail to produce the colour; but when present along with the chromophores in an organic compound intensifies the colour of the chromogen.[1] Examples include the hydroxyl group (−OH), the amino group (−NH2), the aldehyde group (−CHO), and the methyl mercaptan group (−SCH3).[2]

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. If these groups are in direct conjugation with the pi-system of the chromophore, they may increase the wavelength at which the light is absorbed and as a result intensify the absorption. A feature of these auxochromes is the presence of at least one lone pair of electrons which can be viewed as extending the conjugated system by resonance.

Answer 2

Answer:

a)Auxochrome

Explanation:

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.

When the auxochrome –NH2 group is attached to aniline its absorption change from λ max to λ.