Question

Which of the following compounds does not give Friedel-Crafts reaction?

• A. Benzene
• B. Chloro Benzene
• C. Benzoic Acid
• D. Phenol

Hint:

Aromatic rings containing strongly deactivating groups such as \(-NO_2\), \(-SO_3H\), \(-CN\), and \(-COOH\) generally do not undergo Friedel-Crafts reactions.

Answer 1

The Correct Option is C

Concept: Friedel-Crafts alkylation and acylation are electrophilic aromatic substitution reactions carried out in the presence of Lewis acid catalysts such as \(AlCl_3\). For these reactions to occur efficiently, the aromatic ring should not be strongly deactivated. Electron-withdrawing groups decrease electron density on the ring and hinder Friedel-Crafts reactions.

Step 1: Analyze benzene. Benzene readily undergoes Friedel-Crafts alkylation and acylation.

Step 2: Analyze chlorobenzene and phenol. Although chlorobenzene is less reactive than benzene, it can participate under suitable conditions. Phenol contains an electron-donating oxygen atom and activates the ring.

Step 3: Analyze benzoic acid. Benzoic acid contains the strongly electron-withdrawing group: \[ -COOH \] This group significantly deactivates the benzene ring. Moreover, it can interact with the Lewis acid catalyst and suppress the Friedel-Crafts reaction. Therefore, \[ \boxed{\text{Benzoic Acid does not undergo Friedel-Crafts reaction}} \] Hence, the correct option is \[ \boxed{(C)} \]