What is the most characteristic reaction of benzene?(A) addition (B) polymerization(C) reduction (D) substitution
Benzene ring contains six circulating pi-electrons within the six-carbon framework. Pi- electrons are found in alkenes or alkynes too but the pi-electrons in benzene are special in that they constitute an aromatic system, hence the system becomes exceptionally stabilized. Any reaction that requires destruction of this aromatic network is thus intrinsically disfavoured in benzene ring. The chemical reactivity of benzene contrasts with that of the alkenes (or alkynes) in that substitution reactions occur in preference to addition reactions, because addition proceeds with loss of aromaticity of the ring whereas in substitution reaction the aromaticity is preserved.
Therefore, the most charcteristic reaction of benzene ring is electrophilic substitution. The correct answer is option D).
An electrophilic substitution reaction proceeds with initial attack by an electrophile (electron deficient species).