JEE Main · 2026 · 21 Jan 2026 · Shift 1 · Compounds Containing Nitrogen

Nitration of benzene gives nitrobenzene (P), which Sn/HCl reduces to aniline (Q). Acetylation of aniline with acetic anhydride gives acetanilide (R); nitration of acetanilide, directed para by the acetamido group, gives $p$-nitroacetanilide as the major product (S). Acid hydrolysis of the amide in S releases the amine, giving $p$-nitroaniline (T), O${}_2$N$-$C${}_6$H${}_4-$NH${}_2$, of formula C${}_6$H${}_6$N${}_2$O${}_2$ and molar mass $72+6+28+32=138\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$. The nitrogen content is $\frac{28}{138}\times 100=20.3\%$, which to the nearest integer is 20%.