Which of the following hydrocarbons cannot be obtained Sabatier and Senderens reaction

Options

A. `CH_4`
B. `C_2H_6`
C. `C_3H_8`
D. All

Explanation

To determine which hydrocarbon cannot be obtained through the Sabatier and Senderens reaction, we need to understand the nature of this reaction and the types of hydrocarbons involved.

### Step-by-Step Solution:

1. **Understanding the Sabatier and Senderens Reaction**:
- This reaction involves the hydrogenation of unsaturated hydrocarbons (alkenes and alkynes) in the presence of a nickel catalyst. The process converts unsaturated hydrocarbons into saturated hydrocarbons (alkanes).

2. **Identifying Hydrocarbons**:
- Let's consider the hydrocarbons given in the options. We need to identify whether they are saturated or unsaturated.
- Saturated hydrocarbons (alkanes) have the general formula \( C_nH_{2n+2} \) and contain only single bonds.
- Unsaturated hydrocarbons (alkenes and alkynes) have at least one double or triple bond.

3. **Analyzing Each Option**:
- **Option 1: CH4 (Methane)**:
- Methane is an alkane (saturated) with one carbon atom. It cannot be hydrogenated further because it already has the maximum number of hydrogen atoms.
- **Option 2: C2H4 (Ethylene)**:
- Ethylene is an alkene (unsaturated) with two carbon atoms. It can be hydrogenated to form ethane (C2H6).
- **Option 3: C2H2 (Acetylene)**:
- Acetylene is an alkyne (unsaturated) with two carbon atoms. It can be hydrogenated to form ethane (C2H6).
- **Option 4: C3H6 (Propylene)**:
- Propylene is an alkene (unsaturated) with three carbon atoms. It can be hydrogenated to form propane (C3H8).

4. **Conclusion**:
- The only hydrocarbon that cannot be obtained through the Sabatier and Senderens reaction is **Option 1: CH4 (Methane)**, as it is already saturated and does not undergo further hydrogenation.

### Final Answer:
**CH4 (Methane) cannot be obtained by the Sabatier and Senderens reaction.**

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