Which of the following statements is correct regarding the slag obtained during the extraction of a metal like copper or iron?

Options

A. The slag is lighterand has higher melting point than the metal
B. The slag is lighter and has lower melting point than the metal
C. The slag is heavier and has higher melting point than the metal
D. The slag is heavier and has lower melting point than the metal

Answer

To determine the correct statement regarding the slag obtained during the extraction of metals like copper or iron, let's analyze the properties of slag and its formation process step by step.

### Step-by-Step Solution:

1. **Understanding Slag Formation**:
- During the extraction of metals from their ores, impurities (also known as gangue) are present. To remove these impurities, a substance called flux is added.
- The flux reacts with the impurities to form a new compound that is called slag.

2. **Example of Slag Formation**:
- Consider the extraction of iron from its ore, hematite (Fe₂O₃). Hematite contains silicon dioxide (SiO₂) as an impurity.
- Calcium carbonate (CaCO₃) is used as a flux. Upon heating, it decomposes to form calcium oxide (CaO) and carbon dioxide (CO₂).
- The calcium oxide then reacts with the silicon dioxide to form calcium silicate (CaSiO₃), which is the slag.

3. **Properties of Slag**:
- Slag is typically lighter than the molten metal (e.g., molten iron) and has a lower melting point compared to the metal.
- This lighter nature allows the slag to float on the surface of the molten metal, making it easier to remove.

4. **Evaluating the Options**:
- **Option 1**: Slag is lighter and has a higher melting point than the metal. (Incorrect)
- **Option 2**: Slag is lighter and has a lower melting point than the metal. (Correct)
- **Option 3**: Slag is heavier and has a higher melting point than the metal. (Incorrect)
- **Option 4**: Slag is heavier and has a lower melting point than the metal. (Incorrect)

5. **Conclusion**:
- The correct statement regarding the slag obtained during the extraction of metals like copper or iron is **Option 2**: "the slag is lighter and has a lower melting point than the metal."