Which of the following is a difference between thermoplastic and thermosetting plastics ?

Options

A. Thermoplastics can be processed repeatedly.
B. Thermosetting plastics cannot be softened by heating .
C. Thermoplastics do not undergo chemical change on heating.
D. All the above.

Explanation

To identify the differences between thermoplastic and thermosetting plastics, we can analyze the characteristics of each type of plastic. Here’s a step-by-step breakdown of the differences:

### Step 1: Define Thermoplastics
- **Thermoplastics** are types of plastics that can be melted and reshaped multiple times without undergoing any significant chemical change. They can be reheated and reprocessed, which allows for recycling.

### Step 2: Define Thermosetting Plastics
- **Thermosetting plastics**, on the other hand, are plastics that, once set into a given shape, cannot be remelted or reshaped. They undergo a chemical change when heated, which makes them hard and rigid.

### Step 3: Analyze the Options
1. **Option 1**: Thermoplastics can be processed repetitively.
- This is true because thermoplastics can be melted and reshaped multiple times.

2. **Option 2**: Thermosetting plastics cannot be softened by heating.
- This is also true as thermosetting plastics maintain their shape and cannot be remolded once set.

3. **Option 3**: Thermoplastics do not undergo chemical change on heating.
- This is true as thermoplastics undergo physical changes (like melting) but not chemical changes when heated.

### Step 4: Conclusion
- Since all the options provided are correct, the answer to the question is that all of these statements represent differences between thermoplastics and thermosetting plastics.

### Final Answer
- The answer is **Option 4: All of these**.

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