Aniline reacts with mixed acid conc. `HNO_(3)` and conc. `H_(2)SO_(4)` at 288 K to give P (51 %), Q (47%) and R (2%). The major product(s) of the following reaction sequence is (are)

Options

A.
B.
C.
D.

Answer

To solve the problem, we need to analyze the reaction of aniline with a mixture of concentrated nitric acid (HNO₃) and concentrated sulfuric acid (H₂SO₄) at 288 K. This mixture is known as a nitrating mixture, and it will lead to the formation of different nitroaniline products.

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactant is aniline (C₆H₅NH₂), which contains an amino group (-NH₂) attached to a benzene ring.

2. **Understand the Nitration Process**:
- When aniline is treated with the nitrating mixture, nitration can occur at three positions on the benzene ring: ortho (2-position), meta (3-position), and para (4-position) relative to the amino group.

3. **Predict the Products**:
- The products formed will be:
- **P**: Ortho-nitroaniline (major product, 51%)
- **Q**: Para-nitroaniline (second major product, 47%)
- **R**: Meta-nitroaniline (minor product, 2%)

4. **Analyze the Product Distribution**:
- The ortho product is favored due to the electron-donating effect of the amino group, which increases the electron density on the ortho and para positions. However, steric hindrance makes the ortho product less stable than the para product, leading to a significant amount of para product as well.

5. **Identify the Major Product**:
- The major product from the nitration of aniline is ortho-nitroaniline (P, 51%).

6. **Further Reactions with Compound R**:
- The question implies further reactions with the product R (meta-nitroaniline). The sequence of reactions involves:
- Treating R with acetic anhydride (to form an acetanilide derivative).
- Bromination of the acetanilide derivative.
- Acid hydrolysis to regenerate the amine.
- Formation of a diazonium salt and subsequent reactions leading to a brominated product.

7. **Final Product Identification**:
- After the sequence of reactions, the final product is a brominated derivative of aniline, specifically a dibrominated compound.

8. **Conclusion**:
- The major product of the entire reaction sequence is identified as the dibrominated aniline derivative, which corresponds to option D in the given choices.