Which of the following give aniline by reduction of nitrobenzene?

Options

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

Answer

To determine which of the following methods can give aniline by the reduction of nitrobenzene, we will analyze the reduction processes involved.

### Step-by-Step Solution:

1. **Identify Nitrobenzene**:
- Nitrobenzene (C6H5NO2) is the starting compound that we want to reduce to aniline (C6H5NH2).

2. **Reduction Methods**:
- There are several methods to reduce nitrobenzene to aniline. The common methods include:
- Catalytic reduction using palladium on carbon (Pd/C).
- Reduction using active metals like iron (Fe), tin (Sn), or zinc (Zn) in the presence of concentrated hydrochloric acid (HCl).
- Reduction using lithium aluminium hydride (LiAlH4).

3. **Catalytic Reduction with Pd/C**:
- When nitrobenzene is treated with hydrogen (H2) in the presence of palladium on carbon, it gets reduced to aniline:
\[ \text{C6H5NO2} + 3\text{H2} \xrightarrow{\text{Pd/C}} \text{C6H5NH2} + 2\text{H2O} \]
- This method is valid for producing aniline.

4. **Reduction with Active Metals**:
- Nitrobenzene can also be reduced using active metals like Fe or Sn in the presence of concentrated HCl:
\[ \text{C6H5NO2} + 6\text{H} \xrightarrow{\text{Fe/HCl}} \text{C6H5NH2} + 2\text{H2O} \]
- This method is also valid for producing aniline.

5. **Reduction with Lithium Aluminium Hydride**:
- When nitrobenzene is treated with lithium aluminium hydride (LiAlH4) in dry ether, it does not yield aniline. Instead, it forms azobenzene:
\[ \text{C6H5NO2} + \text{LiAlH4} \rightarrow \text{C6H5N=NC6H5} \text{ (azobenzene)} \]
- Therefore, this method does not produce aniline.

6. **Conclusion**:
- The methods that can reduce nitrobenzene to aniline are:
- Catalytic reduction with Pd/C.
- Reduction with active metals (Fe, Sn, Zn) in the presence of concentrated HCl.
- The method using lithium aluminium hydride does not yield aniline.

### Final Answer:
The methods that give aniline by reduction of nitrobenzene are:
- Catalytic reduction with Pd/C
- Reduction with active metals (Fe, Sn, Zn) in concentrated HCl.