Question

Reaction of phenol with dil. $HNO_{3}$ gives

• A. $\text{p}$ and $\text{m}$ -nitrophenols
• B. $\text{o}$ - and $\text{p}$ -nitrophenols
• C. Picric acid
• D. $\text{o}$ - and $\text{m}$ -nitrophenols

Answer 1

Answer: (B)

Phenol reacts with dilute nitric acid at room temperature to give a mixture of 2-nitrophenol and 4-nitrophenol. With concentrated nitric acid. With concentrated nitric acid, more nitro groups substitute around the ring to give 2,4,6-trinitrophenol (common name: picric acid).
If phenol is treated with concentrated nitric acid then picric acid is formed. If phenol is treated with dilute nitric acid, mono or disubstituted nitrophenols are formed. o-nitrophenols are more stable than p-nitrophenols due to intramolecular hydrogen bonding.