Compound '$\mathrm{P}$' on nitration with dil. ${\mathrm{HNO}}_3$ yields two isomers $\left(\mathrm{A}\right)$ and $\left(\mathrm{B}\right)$. These isomers can be separated by steam distillation. Isomers $\left(\mathrm{A}\right)$ and $\left(\mathrm{B}\right)$ show intramolecular and intermolecular hydrogen bonding respectively. Compound $\left(\mathrm{P}\right)$ on reaction with conc. ${\mathrm{HNO}}_3$ yields a yellow compound '$\mathrm{C}$', a strong acid. The number of oxygen atoms is present in compound ‘$C$’

Step 1: Understanding the problem

• Compound P undergoes nitration with dilute HNO₃ to yield two isomers (A) and (B).
  • (A): Shows intramolecular hydrogen bonding.
  • (B): Shows intermolecular hydrogen bonding.
  • These can be separated by steam distillation, indicating volatility differences.
• Compound P reacts with concentrated HNO₃ to yield compound C, which is a yellow, strong acid.
• Goal: Determine the number of oxygen atoms in compound C.

Step 2: Key insights

1. Nature of Compound P:
   • The ability to form two nitrated isomers (one with intramolecular H-bonding and the other with intermolecular H-bonding) suggests phenol derivatives.
   • Phenols can undergo nitration to yield ortho- and para-nitrophenols.
   • Ortho-nitrophenol forms intramolecular H-bonding, while para-nitrophenol forms intermolecular H-bonding.
2. Steam distillation:
   • Ortho-nitrophenol (lower boiling point due to intramolecular H-bonding) is volatile and separates from para-nitrophenol (higher boiling point due to intermolecular H-bonding).
3. Reaction with conc. HNO₃:
   • Phenol reacts with concentrated HNO₃ to yield picric acid (2,4,6-trinitrophenol), a yellow-colored compound and a strong acid.

Step 3: Reactions

1. Nitration with dilute HNO₃:
   Phenol (P) undergoes nitration to yield:

   $$P \xrightarrow{\text{dil. HNO₃}} A + B$$

   C: Picric acid.

   Step 4: Picric acid structure

2. Picric acid (2,4,6-trinitrophenol) has the structure:
3. A benzene ring with:
   1. Three nitro groups (-NO₂) at positions 2, 4, and 6.
   2. One hydroxyl group (-OH) at position 1.

4. Each -NO₂ group contributes 2 oxygen atoms and the -OH group contributes 1 oxygen atom.

   Step 5: Total oxygen atoms in Compound C (picric acid)

5. Number of oxygen atoms from 3 nitro groups: $3 \times 2 = 6$.
6. Number of oxygen atoms from 1 hydroxyl group: $1$.
7. Total oxygen atoms = 6 + 1 = 7.