Substituents on an aromatic ring can have several effects on electrophilic aromatic substitution reactions. Substituents can activate or deactivate the ring to substitution, donate or withdraw electrons inductively, donate or withdraw electrons through resonance, and direct substitution either to the ortho/para or to the meta positions. From the following lists, select the substituents that have the indicated property. The substituents are written as -XY, where X is the atom directly bound to the aromatic ring.

Activation of the ring towards substitution

A) -NHCOCH3
B) -COOH
C) -CH3
D) -SO3H

The option A that is -NHCOCH3 is CORRECT because it possesses lone pair of electron with the exception of group 7A elements. It is this lone pair that is used in the Activation of the ring towards substitution. Other groups that falls into this group are; OCH3, alkyls and many others.

Option B that is -COOH is good group for withdrawal of electron through Resonance. Other examples are NO2, -CN and SO3H.

Option C falls to the same category as option A above that is Activation of the ring towards substitution.

Option D falls to the same category as option B above that is group for withdrawal of electron through Resonance.