Concept:The hydroxyl group is powerfully activating. Treatment with a highly concentrated electrophile source will lead to exhaustive substitution at all available activated positions.
Formula:$$ \text{C}_6\text{H}_5\text{OH} + 3\text{HNO}_3 \xrightarrow{\text{Conc. H}_2\text{SO}_4} \text{C}_6\text{H}_2(\text{NO}_2)_3\text{OH} + 3\text{H}_2\text{O} $$
Solution:- Using a full nitrating mixture (concentrated nitric and sulfuric acid) with a 3:1 molar ratio ensures maximum nitration.
- The nitro groups attach to both ortho positions (2, 6) and the para position (4).
- The resulting compound is 2,4,6-trinitrophenol, known commonly as picric acid.
Why other options are incorrect:Options A, B, and C describe the products obtained when using
dilute nitric acid at lower temperatures, which yields only mono-substitution.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.