Question

Which of the following is easily nitrated using a mixture of \(HNO_3\) and \(H_2SO_4\):

• A. Toluene
• B. Fluorobenzene
• C. Chlorobenzene
• D. Nitrobenzene

Hint:

Toluene undergoes nitration faster than benzene due to its electron-donating methyl group (+I effect), increasing its reactivity in electrophilic aromatic substitution reactions.

Answer 1

The Correct Option is A

Step 1: Understanding the nitration reaction. Nitration is an electrophilic aromatic substitution reaction where a benzene derivative reacts with a mixture of concentrated nitric acid (\(HNO_3\)) and sulfuric acid (\(H_2SO_4\)) to introduce a nitro group (-NO\(_2\)) onto the aromatic ring. 

Step 2: Reactivity of the given compounds. - Toluene (\(C_6H_5CH_3\)) has a +I (electron-donating) methyl group, which increases the electron density on the benzene ring, making it highly reactive towards nitration. 
- Fluorobenzene (\(C_6H_5F\)) has a fluorine atom, which has both electron-donating and electron-withdrawing effects, but its overall influence is deactivating. 
- Chlorobenzene (\(C_6H_5Cl\)) is less reactive than benzene due to chlorine’s -I effect (electron withdrawal). 
- Nitrobenzene (\(C_6H_5NO_2\)) has a strong -I and -M effect (electron-withdrawing), making it very deactivated toward further nitration.

Conclusion. Since toluene is the most activated due to the electron-donating methyl group, it undergoes nitration most easily.