Consider the following sequence of reaction
The final product (Q) is`Ph-NO_2overset(Sn//HCl)rarr(X)overset(NaNO_2//HCl)rarrPoverset(CuBr//HBr)rarr(Q)` The final product (Q) is

Options

A. chlorbenzene
B. bromobenzene
C. benzyl bromide
D. benzyl chloride

Answer

To determine the final product (Q) from the given sequence of reactions, let's break down each step systematically.

### Step-by-Step Solution:

1. **Starting Compound**: The reaction begins with nitrobenzene (Ph-NO2).

2. **First Reaction**: Nitrobenzene reacts with tin (Sn) and hydrochloric acid (HCl).
- **Reaction Type**: This is a reduction reaction.
- **Product**: The nitro group (NO2) is reduced to an amino group (NH2).
- **Resulting Compound (X)**: The product of this reaction is aniline (Ph-NH2).

3. **Second Reaction**: Aniline (X) is then treated with sodium nitrite (NaNO2) and hydrochloric acid (HCl) at low temperatures (0-5°C).
- **Reaction Type**: This is a diazotization reaction.
- **Product**: Aniline is converted into benzene diazonium chloride (Ph-N2^+Cl^-).
- **Resulting Compound (P)**: The product formed is Ph-N2^+Cl^-.

4. **Third Reaction**: The benzene diazonium chloride (P) is then reacted with copper(I) bromide (CuBr) in the presence of hydrobromic acid (HBr).
- **Reaction Type**: This is a Sandmeyer reaction.
- **Product**: The diazonium group (N2) is replaced by a bromine atom (Br).
- **Resulting Compound (Q)**: The final product is bromobenzene (Ph-Br).

### Final Product:
The final product (Q) is **bromobenzene (Ph-Br)**.

### Conclusion:
After analyzing the sequence of reactions, we conclude that the final product (Q) is bromobenzene.

---