Question

Which of the following compounds undergoes electrophilic substitution most readily?

• A. Nitrobenzene
• B. Toluene
• C. Benzene
• D. Benzoic acid

Hint:

\textbf{Tip:} Electron-donating groups (e.g., –CH\(_3\)) activate benzene rings; electron-withdrawing groups (e.g., –NO\(_2\)) deactivate them.

Answer 1

The Correct Option is B

The compound that undergoes electrophilic substitution most readily among the given options is determined by the electron-donating or electron-withdrawing nature of substituents on the aromatic ring. Electrophilic substitution reactions proceed more readily in aromatic compounds with electron-donating groups, which activate the ring by increasing electron density. Let's evaluate the options:

• Nitrobenzene: Features a nitro group (-NO₂), an electron-withdrawing substituent that deactivates the benzene ring toward electrophilic substitution.
• Toluene: Contains a methyl group (-CH₃), an electron-donating substituent. This increases electron density on the benzene ring, activating it for electrophilic substitution reactions.
• Benzene: A standard aromatic compound lacking substituents. It exhibits lower reactivity than toluene due to the absence of electron-donating groups.
• Benzoic acid: Possesses a carboxyl group (-COOH), an electron-withdrawing substituent that deactivates the benzene ring.

Among these, Toluene undergoes electrophilic substitution most readily, owing to the electron-donating methyl group that enhances the aromatic ring's reactivity toward electrophiles.