Question

Which of the following sequence of reactions is suitable to synthesize chlorobenzene?

• A. Benzene, Cl₂, anhydrous FeCl₃
• B. Phenol, NaNO₂, HCl, CuCl
• C. HCl
• D. HCl, Heating

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Chlorobenzene is an aryl halide. Synthesis usually involves electrophilic aromatic substitution or displacement of a diazonium group.
Step 2: Detailed Explanation:
1. Option (1): Benzene reacts with chlorine in the presence of a Lewis acid catalyst like anhydrous $FeCl_3$. This is a classic Electrophilic Aromatic Substitution (SEAr) reaction where $Cl^+$ is the electrophile. This successfully produces chlorobenzene.
2. Option (2): Phenol does not undergo direct displacement of the $-OH$ group by $Cl$ using these reagents. $NaNO_2/HCl$ is for diazotization of amines, not phenols.
3. Option (3): Reaction of pyridine with $HCl$ gives a pyridinium salt, not chlorobenzene.
4. Option (4): Aniline with $HCl$ gives anilinium chloride. Heating it doesn't yield chlorobenzene; it requires diazotization followed by Sandmeyer's reaction.
Step 3: Final Answer:
Direct chlorination of benzene with a catalyst is the correct laboratory method to synthesize chlorobenzene.