Which of the followingg reactions of methane is incomplete combustion?

Explanation

To determine which reaction of methane represents incomplete combustion, we need to understand the concept of combustion reactions, specifically the difference between complete and incomplete combustion.

### Step-by-Step Solution:

1. **Define Combustion**: Combustion is a chemical reaction where a substance (usually a hydrocarbon) reacts with oxygen to produce heat and light.

2. **Types of Combustion**:
- **Complete Combustion**: This occurs when there is a sufficient supply of oxygen. The products are carbon dioxide (CO₂) and water (H₂O).
- **Incomplete Combustion**: This occurs when there is an insufficient supply of oxygen. The products can include carbon monoxide (CO), carbon (soot or carbon black), and water (H₂O).

3. **Identify the Reaction**: We need to analyze the given reactions of methane (CH₄) to see which one indicates incomplete combustion.

4. **Look for Products**: In the reactions:
- If the products include carbon monoxide (CO) or carbon (C), then it indicates incomplete combustion.
- If the products are only carbon dioxide (CO₂) and water (H₂O), then it indicates complete combustion.

5. **Example Reactions**:
- **Complete Combustion of Methane**:
\[ CH₄ + 2O₂ \rightarrow CO₂ + 2H₂O \]
- **Incomplete Combustion of Methane**:
\[ 2CH₄ + 3O₂ \rightarrow 2CO + 4H₂O \]
or
\[ CH₄ + O₂ \rightarrow C + 2H₂O \]

6. **Conclusion**: From the analysis, the reaction that produces carbon (C) or carbon monoxide (CO) indicates incomplete combustion. Therefore, we need to select the reaction from the options provided that shows these products.

### Final Answer:
The reaction of methane that represents incomplete combustion is the one that produces carbon (C) or carbon monoxide (CO).