Acetylene does not show which of the following reactions?

Options

A. Condensation
B. Polymerization
C. Addition reactions
D. Combustion reaction.

Answer

To determine which reaction acetylene (C2H2) does not show, we will analyze the four types of reactions mentioned: condensation, addition, polymerization, and combustion.

### Step-by-Step Solution:

1. **Identify Acetylene**:
- Acetylene is a simple alkyne with the formula C2H2. It has a triple bond between the two carbon atoms.

2. **Condensation Reaction**:
- **Definition**: A condensation reaction involves the combination of two molecules to form a larger molecule, with the elimination of a small molecule (like water).
- **Analysis**: Acetylene does not typically undergo condensation reactions because it does not have the necessary functional groups or conditions to facilitate this type of reaction.
- **Conclusion**: Acetylene does not show condensation reactions.

3. **Addition Reaction**:
- **Definition**: Addition reactions involve the addition of atoms or groups to a molecule, typically at a double or triple bond.
- **Analysis**: Acetylene can undergo addition reactions due to its triple bond. For example, it can react with bromine (Br2) in the presence of CCl4 to form dibromoethene.
- **Conclusion**: Acetylene does show addition reactions.

4. **Polymerization Reaction**:
- **Definition**: Polymerization is a process where small molecules (monomers) combine to form a larger molecule (polymer).
- **Analysis**: Acetylene can undergo polymerization under certain conditions (e.g., in the presence of red-hot iron) to form larger carbon structures, such as benzene.
- **Conclusion**: Acetylene does show polymerization reactions.

5. **Combustion Reaction**:
- **Definition**: Combustion reactions involve the reaction of a substance with oxygen to produce heat and light, typically resulting in carbon dioxide and water.
- **Analysis**: Acetylene burns in the presence of oxygen to produce carbon dioxide (CO2) and water (H2O).
- **Conclusion**: Acetylene does show combustion reactions.

### Final Answer:
Acetylene does not show **condensation reactions**.