Question

Toluene reacts with a halogen in the presence of iron (III) chloride giving ortho and para compounds. The reaction is:

• A. Electrophilic addition reaction
• B. Electrophilic substitution reaction
• C. Free radical substitution reaction
• D. Nucleophilic substitution reaction

Hint:

Always look at the substituent that is already attached to the benzene ring to figure out whether the incoming electrophile will attach itself at the ortho/para position, or the meta position, and this depends on the group’s ability to donate or withdraw electron density via resonance or induction.

Answer 1

The Correct Option is B

Toluene undergoes electrophilic substitution when treated with halogens in the presence of \(FeCl_{3}\), a Lewis acid catalyst. The methyl group on toluene activates the ortho and para positions for substitution due to its electron-donating effect. The reaction mechanism involves:
Generation of an electrophile \((e.g., Cl^{+}) by FeCl_{3}\)
Electrophile attack at the activated positions.
Stabilization of the intermediate carbocation and subsequent restoration of aromaticity.
This reaction is characteristic of aromatic compounds.