Question

The electrophilic aromatic substitution proceeds through :

Answer 1

In electrophilic aromatic substitution, Formation of an arenium ion (intermediate) is there which is partially stabilized by resonance.
This cation is called sigma complex because the electrophile is joined to the benzene ring through a new sigma bond.
The sigma complex is non aromatic in nature and can regain its aromaticity by loss of proton.
Thus, electrophilic aromatic substitution proceeds through a sigma complex given below: