Q.Among the following, the reaction that proceeds through an electrophilic substitution is:

Step 1. Option (a), the diazonium salt + Cu2Cl2 (Sandmeyer reaction), proceeds through a radical-type mechanism involving copper(I)/copper(II) redox cycling, not classical electrophilic aromatic substitution.

Step 2. Option (b), benzene + Cl2 with the Lewis-acid catalyst AlCl3, is the textbook definition of electrophilic aromatic substitution: AlCl3 polarises Cl2 to generate an electrophilic Cl+-like species, which attacks the ring's pi electrons, forming an arenium (sigma-complex) intermediate before a proton is lost to restore aromaticity.

Step 3. Option (c), benzene + Cl2 under UV light with no catalyst, proceeds by a free-radical chain ADDITION mechanism (not substitution at all), giving hexachlorocyclohexane -- all six ring carbons become saturated. …

Classify each reaction's actual mechanism type (radical redox, electrophilic aromatic substitution, radical addition, nucleophilic substitution) rather than assuming 'any reac …

• Picking the Sandmeyer reaction (a) just because it also involves an aromatic ring and a halogen ending up on it -- Sandmeyer proceeds by a fundamentally different, radical-based mechanism, not the Lewi …