WBJEE 2024 Physics & Chemistry Paper

Toluene, which is also known as methylbenzene, undergoes nitration when reacted with mixed acid, typically a mixture of concentrated nitric acid $(\mathrm{HNO}_3)$ and concentrated sulfuric acid $(\mathrm{H}_2\mathrm{SO}_4)$. This reaction introduces a nitro group $(-\mathrm{NO}_2)$ onto the benzene ring of toluene. The methyl group $(-\mathrm{CH}_3)$ attached to the benzene ring is an electron-donating group (EDG) and it activates the ortho ( 2 and 6 ) and para (4) positions on the ring, making them more susceptible to electrophilic substitution reactions.Among the given options, let's evaluate them in detail:Option A: This suggests that toluene produces nearly equal amounts of $o$ nitrotoluene (ortho-nitrotoluene) and $\underset{\overline{}}{m}$ - nitrotoluene (meta-nitrotoluene). However, because the methyl group is an activating and ortho/para-directing group, metanitrotoluene is produced in very minor amounts compared to ortho and para isomers.Option B: This suggests that the reaction only produces $\underset{\overline{}}{p}$ - nitrotoluene. While the para isomer is one of the products, it is not the only product. The ortho isomer is also formed in significant amounts.Option C: This option suggests that the reaction predominately produces $\underset{\overline{}}{o}$ nitrotoluene and $p$ - nitrotoluene. This is correct because the methyl group directs the nitration to the ortho and para positions on the benzene ring.Option D: This suggests that the reaction produces 2, 4, 6-trinitrotoluene (TNT) only. This is not true at the given condition $(25^{\circ}\,\mathrm{C})$, as the formation of TNT requires more stringent conditions including higher temperature and multiple steps of nitration.Therefore, the correct answer is:Option C: predominantly $\underset{\overline{}}{o}$ - nitrotoluene and $\underset{\overline{}}{p}$ - nitrotoluene