JEE Main · 2026 · 05 Apr 2026 · Shift 1 · Alcohols Phenols and Ethers

Nitration of phenol with dilute nitric acid at $298\mathrm{K}$ gives a mixture of ortho- and para-nitrophenol, and of these the ortho isomer is steam-volatile, since its intramolecular hydrogen bond prevents the intermolecular association that would hold it back, so X is o-nitrophenol. In phenol, ${\mathrm{C}}_6{\mathrm{H}}_6\mathrm{O}$ of molar mass $94$, the mass fraction of oxygen is $\frac{16}{94}\times 100=17.02\%$. In o-nitrophenol, ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N}{\mathrm{O}}_3$ of molar mass $139$, it is $\frac{48}{139}\times 100=34.53\%$. The rise is $34.53-17.02=17.51\%$, equal to $175\times 10^{-1}\%$, so the nitrogen percentage is $175$.