Which of these fibres melt away on heating?

Options

A. Acrylic
B. Cotton
C. Rayon
D. Silk

Explanation

To determine which fibers melt away on heating, we need to analyze the properties of the given fibers. Let's break down the solution step by step.

### Step-by-Step Solution:

1. **Understanding Fiber Types**:
- There are various types of fibers, including natural fibers (like cotton and wool) and synthetic fibers (like polyester, nylon, and acrylic).
- Synthetic fibers are often made from polymers, which can have different thermal properties.

2. **Identifying Melting Behavior**:
- Some synthetic fibers have low melting points and will melt when exposed to heat.
- For example, acrylic fibers are known to have a low melting point compared to other synthetic fibers.

3. **Analyzing Acrylic Fiber**:
- Acrylic is a synthetic fiber that is made from acrylonitrile monomers.
- The structure of acrylic contains ester linkages, which contribute to its lower melting point.

4. **Conclusion**:
- Among the options provided, acrylic is the fiber that melts away on heating due to its low melting point.

### Final Answer:
**Acrylic fibers melt away on heating.**

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