The example of thermosetting and thermoplastic polymer respectively is

Options

A. Polystyrene, polyvinyl chloride
B. Bakelite, polystyrene
C. Polyethene, polyacrylonitrile
D. Polystyrene, urea-formaldehyde resin

Answer

To answer the question regarding examples of thermosetting and thermoplastic polymers, let's break down the concepts step by step.

### Step 1: Understand Thermosetting Polymers
Thermosetting polymers are materials that, once set into a given shape, cannot be remolded or reshaped by heating. They undergo a chemical change when cured, which gives them a rigid structure.

**Hint**: Remember that thermosetting polymers are like a cake that, once baked, cannot be reshaped.

### Step 2: Characteristics of Thermosetting Polymers
These polymers typically have high melting points and high tensile strength. They are formed through a process called condensation polymerization.

**Hint**: Think of thermosetting polymers as strong and permanent, similar to a solid structure that cannot be altered.

### Step 3: Examples of Thermosetting Polymers
Common examples of thermosetting polymers include Bakelite and polyester. Bakelite is a well-known thermosetting plastic used in electrical insulators and household items.

**Hint**: Bakelite is a classic example; think of it as a durable material used in various applications.

### Step 4: Understand Thermoplastic Polymers
Thermoplastic polymers, on the other hand, can be melted and reshaped multiple times without undergoing any significant chemical change. They are more flexible and can be recycled.

**Hint**: Imagine thermoplastic polymers as playdough that can be reshaped and reused.

### Step 5: Characteristics of Thermoplastic Polymers
These polymers can be heated to a point where they melt, allowing them to be molded into new shapes. This process can be repeated indefinitely.

**Hint**: Consider thermoplastics as materials that are adaptable and can be reformed easily.

### Step 6: Examples of Thermoplastic Polymers
Common examples of thermoplastic polymers include polystyrene, Teflon, and nylon. Polystyrene is widely used in packaging and insulation.

**Hint**: Polystyrene is often found in disposable cups and containers, making it a familiar example.

### Conclusion
Based on the definitions and examples discussed, the answer to the question is:
- **Thermosetting Polymer**: Bakelite
- **Thermoplastic Polymer**: Polystyrene

Thus, the correct answer is **Option B**.