Which of the following polymers are condensation polymers?

Options

A. Bakelite
B. Teflon
C. Butyl rubber
D. Melamine formaldehyde resin

Explanation

To determine which of the given polymers are condensation polymers, we will analyze each option based on their polymerization process and the presence of byproducts.

### Step-by-Step Solution:

1. **Understand the Definition of Condensation Polymers**:
- Condensation polymers are formed through a reaction where monomers combine with the elimination of a small molecule, typically water. This is in contrast to addition polymers, which do not produce byproducts during their formation.

2. **Analyze Each Option**:
- **Option 1: Bakelite**
- Bakelite is formed from the polymerization of phenol and formaldehyde. During this reaction, water is released as a byproduct. Therefore, Bakelite is a condensation polymer.

- **Option 2: Teflon**
- Teflon is made from tetrafluoroethene (CF2=CF2). It undergoes addition polymerization, where the monomers add together without the loss of any small molecules. Thus, Teflon is not a condensation polymer.

- **Option 3: Butyl Rubber**
- Butyl rubber is synthesized from the polymerization of isobutylene. Similar to Teflon, this process is an addition polymerization, which does not involve the elimination of byproducts. Hence, butyl rubber is not a condensation polymer.

- **Option 4: Melamine Formaldehyde Resin**
- Melamine formaldehyde resin is produced from the reaction of melamine and formaldehyde. This reaction also results in the release of water as a byproduct, indicating that it is a condensation polymer.

3. **Conclusion**:
- Based on the analysis, the polymers that are condensation polymers from the given options are:
- **Bakelite (Option 1)**
- **Melamine Formaldehyde Resin (Option 4)**

### Final Answer:
The condensation polymers among the given options are:
- **Bakelite (Option 1)**
- **Melamine Formaldehyde Resin (Option 4)**