Reduction of nitrobenzene by which of the following reagent gives aniline?

Options

A. `Sn//HCl`
B. `Fe//HCl`
C. `H_(2)-Pd`
D. `Sn//NH_(4)OH`

Explanation

To determine which reagents can reduce nitrobenzene to aniline, we need to understand the reduction process involved. The reduction of nitrobenzene (C6H5NO2) to aniline (C6H5NH2) involves the conversion of the nitro group (-NO2) to an amino group (-NH2). Here’s a step-by-step solution:

### Step 1: Identify the Reduction Reaction
The reduction reaction we are looking at is:
\[ \text{C}_6\text{H}_5\text{NO}_2 \xrightarrow{\text{reductant}} \text{C}_6\text{H}_5\text{NH}_2 \]

### Step 2: Choose Appropriate Reducing Agents
We need to select reducing agents that can facilitate the conversion of nitrobenzene to aniline. Common reducing agents for this reaction include:
- Tin (Sn) with hydrochloric acid (HCl)
- Iron (Fe) with hydrochloric acid (HCl)
- Hydrogen gas (H2) with palladium (Pd) as a catalyst

### Step 3: Evaluate Each Option
1. **Sn + HCl**: Tin in the presence of hydrochloric acid can effectively reduce nitrobenzene to aniline.
2. **Fe + HCl**: Iron with hydrochloric acid also serves as a reducing agent to convert nitrobenzene to aniline.
3. **H2 + Pd**: Hydrogen gas with palladium as a catalyst can reduce nitrobenzene to aniline.
4. **Sn + NH4OH**: This combination does not provide the necessary acidic environment for reduction, as NH4OH is a base.

### Step 4: Conclusion
The reagents that can reduce nitrobenzene to aniline are:
- A: Sn + HCl
- B: Fe + HCl
- C: H2 + Pd

The option that does not work is:
- D: Sn + NH4OH (this is not suitable for reduction).

### Final Answer
The correct options are A, B, and C.

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