Phenol, on heating with conc. \( \mathrm{HNO_3} \), gives :
Phenol, on heating with conc. \( \mathrm{HNO_3} \), gives :
Show Hint
- o-Nitrophenol
- p-Nitrophenol
- Picric acid
- Sodium phenoxide
The Correct Option is C
Solution and Explanation
The -OH group pushes electrons into the ring by resonance. It activates the ortho and para positions strongly towards electrophiles.
So phenol is nitrated much more easily than benzene.
Step 2: Match the reagent strength to the product.
Dilute \( \mathrm{HNO_3} \) at low temperature gives a mixture of o-nitrophenol and p-nitrophenol.
Concentrated \( \mathrm{HNO_3} \) on heating nitrates all three activated positions (2, 4 and 6). The product is 2,4,6-trinitrophenol, called picric acid.
\[ \mathrm{C_6H_5OH + 3HNO_3 \rightarrow C_6H_2(NO_2)_3OH + 3H_2O} \]
Step 3: Check the options.
(A) and (B) are mono-nitro products from dilute acid, so they are wrong here.
(D) Sodium phenoxide forms when phenol reacts with NaOH, and nitric acid does not make it. So (D) is wrong.
(C) picric acid is the correct product.
Final Answer:
Phenol with hot conc. \( \mathrm{HNO_3} \) gives picric acid. \[ \boxed{\text{(C) Picric acid}} \]
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