Concept:The hydroxyl group on the benzene ring is powerfully activating, allowing multiple electrophilic substitutions to occur rapidly without a strong Lewis acid catalyst.
Formula:$$ \text{C}_6\text{H}_5\text{OH} + 3\text{HNO}_3\text{(conc.)} \longrightarrow \text{C}_6\text{H}_2(\text{NO}_2)_3\text{OH} + 3\text{H}_2\text{O} $$
Solution:- Using concentrated nitric acid pushes the nitration to its limit.
- Nitro groups attach to all sterically and electronically favored positions: ortho, para, and the other ortho position.
- The resulting compound is 2,4,6-trinitrophenol, commonly known as picric acid.
Why other options are incorrect:Options C and D are mono-substituted products, which form only when using highly diluted, cold nitric acid. Adipic acid is an aliphatic dicarboxylic acid used in nylon synthesis, completely unrelated to this reaction.
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