In the reaction, if $\mathrm{X}$ is the reagent and $\mathrm{Y}$ is the product, which of the following is not feasible? In the reaction, if $\mathrm{X}$ is the reagent and $\mathrm{Y}$ is the product, which of the following is not feasible?

• A

  $\mathrm{X}=$ Conc. $\mathrm{HNO}_3+$ Con. $\mathrm{H}_2 \mathrm{SO}_4$; $\mathrm{Y}=3-$ Nitrobenzoic acid
• B

  $\mathrm{X}=\mathrm{Br}_2 / \mathrm{Fe} \quad \mathrm{Y}=3-$ Bromobenzoic acid
• C

  $\mathrm{X}=\mathrm{NaOH}, \mathrm{CaO} \quad \mathrm{Y}=$ Benzene
• Correct answer
  D

  $\mathrm{X}=\mathrm{CH}_3 \mathrm{Cl} / \mathrm{AlCl}_3 \quad \mathrm{Y}=3-$ Methylebenzoic acid

Solution

This reaction is not feasible because the $-\mathrm{COOH}$ group interacts with the lewis acid $\mathrm{AlCl}_3$ and forms acylium ion instead of the usual electrophilic substitution at the ring.

Hence, the correct answer is option: 'D'.