JEE Main · 2026 · 23 Jan 2026 · Shift 1 · Compounds Containing Nitrogen

Tin and hydrochloric acid reduce the nitro group of 4-nitrotoluene, and after neutralisation the product A is 4-methylaniline (p-toluidine), ${\text{CH}}_3{\text{C}}_6{\text{H}}_4{\text{NH}}_2$. Acetic anhydride acetylates the amino group to give p-acetotoluidide, ${\text{CH}}_3{\text{C}}_6{\text{H}}_4{\text{NHCOCH}}_3$; the acetamido group is strongly activating and ortho/para directing, and since the para position is already occupied by the methyl group, bromination with ${\text{Br}}_2$ in acetic acid introduces one bromine ortho to it. The product B is N-(2-bromo-4-methylphenyl)acetamide, ${\text{C}}_9{\text{H}}_{10}\text{BrNO}$, of molar mass $228{\text{g mol}}^{-1}$. From $137\text{mg}$ of 4-nitrotoluene, $n=\frac{137\times 10^{-3}}{137}=1\times 10^{-3}\text{mol}$, and with one-to-one stoichiometry the mass of B is $1\times 10^{-3}\times 228=228\text{mg}$.