Which of the following is used for the preparation of benzene ?

Options

A. Phenol
B. Ethyne
C. Furan
D. Both (1) and (2)

Answer

To determine which of the options can be used for the preparation of benzene, we will analyze the possible methods of synthesis.

### Step-by-Step Solution:

1. **Understanding Benzene Structure**:
- Benzene has the molecular formula C6H6 and consists of a ring structure with alternating double bonds, which indicates the delocalization of pi electrons.

2. **Preparation from Phenol**:
- One method for preparing benzene is through the reduction of phenol. When phenol (C6H5OH) is treated with zinc dust, it acts as a reducing agent, converting phenol into benzene (C6H6).
- **Reaction**:
\[ C_6H_5OH + Zn \rightarrow C_6H_6 + ZnO \]
- This indicates that phenol can be used to prepare benzene.

3. **Preparation from Ethylene**:
- Another method involves the cyclic polymerization of ethylene (C2H4). When three ethylene molecules are heated in the presence of a red-hot iron tube at a high temperature (873 K), they undergo a reaction to form benzene.
- **Reaction**:
\[ 3 C_2H_4 \xrightarrow{873 K, \text{red-hot iron}} C_6H_6 \]
- This shows that ethylene can also be used to prepare benzene through cyclic polymerization.

4. **Exclusion of Furan**:
- Furan (C4H4O) does not have the necessary structure to be converted into benzene. Its ring structure and functional groups do not allow for the formation of a benzene molecule.

5. **Conclusion**:
- Based on the above analysis, both phenol and ethylene can be used to prepare benzene, while furan cannot. Therefore, the correct answer is that both phenol and ethylene are used for the preparation of benzene.

### Final Answer:
- **Both A (Phenol) and B (Ethylene) are correct for the preparation of benzene.**