Question

The product(s) formed when toluene is reacted with \(Cl_2\) in the presence of Fe in dark is/are 
 

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

Remember: \[ Cl_2/FeCl_3 \] or \[ Br_2/FeBr_3 \] causes electrophilic aromatic substitution on the benzene ring. \[ Cl_2/h\nu \] causes free-radical side-chain halogenation in alkyl benzenes.

Answer 1

The Correct Option is A

Step 1: Identify the reaction conditions.
The reaction is carried out with \[ Cl_2/Fe \] in the dark. Iron reacts with chlorine to generate \[ FeCl_3 \] which acts as a Lewis acid catalyst and promotes electrophilic aromatic substitution.

Step 2: Determine the directing effect of the methyl group.
In toluene, \[ C_6H_5CH_3 \] the methyl group is an electron-donating group due to the \(+I\) effect and hyperconjugation.
Therefore, it activates the benzene ring and directs incoming electrophiles to the ortho and para positions.

Step 3: Write the chlorination reaction.
The electrophile generated is \[ Cl^+ \] which substitutes a hydrogen atom on the aromatic ring. The major products formed are: \[ o\text{-chlorotoluene} \] and \[ p\text{-chlorotoluene} \] \[ C_6H_5CH_3 \xrightarrow[dark]{Cl_2/Fe} o\text{-chlorotoluene} + p\text{-chlorotoluene} \]

Step 4: Explain why side-chain chlorination does not occur.
Side-chain chlorination proceeds through a free-radical mechanism and requires \[ h\nu \] or heat. Since the reaction is carried out in the dark and in the presence of Fe, free-radical chlorination is suppressed.
Hence benzyl chloride is not formed.

Step 5: Final conclusion.
Therefore, chlorination occurs on the aromatic ring and the products obtained are \[ \boxed{\text{ortho-chlorotoluene and para-chlorotoluene}} \] Hence, option (1) is correct.