WBJEE 2026 Physics and Chemistry Paper

Concept:The IUPAC name is decided by numbering the benzene ring so that the substituents receive the lowest possible set of locants.Explanation:The benzene ring carries three substituents: chloro $-\mathrm{Cl}$, methyl $-\mathrm{CH}_3$, and nitro $-\mathrm{NO}_2$.Number the ring to obtain the smallest locant set, which is $\{1,2,4\}$.Arrange the substituents alphabetically: chloro, methyl, nitro.So the locants are assigned as $1$-chloro, $4$-methyl, and $2$-nitro.Hence, the correct IUPAC name is 1-chloro-4-methyl-2-nitrobenzene.Option D is a common name, not the systematic IUPAC name.Answer:B. 1-Chloro-4-methyl-2-nitrobenzene