Iron possesses good casting properies when compared with copper because

Options

A. iron contracts on solidification.
B. iron expands on solidification.
C. copper expands on solidification.
D. Copper neither contracts nor expands on solidification.

Answer

**Step-by-Step Solution:**

1. **Understanding Casting Properties**: When discussing casting properties of metals, it's important to know how they behave when they transition from liquid to solid. The ideal metal for casting should maintain its shape and size during solidification.

2. **Analyzing Iron and Copper**:
- **Iron**: When iron solidifies, it expands. This means that as it cools and turns from liquid to solid, it occupies more space.
- **Copper**: In contrast, copper contracts when it solidifies. This means that as it cools and solidifies, it takes up less space.

3. **Evaluating the Effects of Expansion and Contraction**:
- **Expansion (Iron)**: The expansion of iron during solidification is beneficial because it helps fill the mold completely. This reduces the chances of defects such as voids or gaps in the final cast.
- **Contraction (Copper)**: The contraction of copper can lead to issues like shrinkage cavities or incomplete filling of the mold, making it less desirable for casting purposes.

4. **Conclusion**: Given that iron expands on solidification, it possesses better casting properties compared to copper, which contracts. Therefore, the correct answer is that iron's ability to expand during solidification makes it more suitable for casting applications.

**Final Answer**: Iron possesses good casting properties when compared with copper because **iron expands on solidification** (Option 2).

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