Which of the following statement is correct ?

Options

A. Roasting is unnecessarily done for `Fe` extraction because there is no sulphide ore
B. In the smelting step of `Cu` extraction, reduction of the ore takes place
C. Ore may not be mineral
D. Sphalerite is the ore of zinc

Answer

To determine which of the statements is correct regarding the extraction of metals, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyzing Statement A**:
- The statement claims that roasting is unnecessarily done for Fe extraction because there is no sulphide ore.
- **Evaluation**: This statement is incorrect. Iron ores often contain sulphide impurities, which need to be removed. Roasting converts these sulphide ores into oxides, making it a necessary step in the extraction process.

**Hint**: Remember that roasting is important for ores that contain sulphides to convert them into oxides.

2. **Analyzing Statement B**:
- The statement suggests that in the smelting of copper extraction, reduction of the ore takes place.
- **Evaluation**: This is also incorrect. In smelting, the ore undergoes oxidation, not reduction. Smelting typically involves heating the ore in the presence of a reducing agent, but the ore itself is oxidized.

**Hint**: Smelting involves oxidation processes, so think about the chemical changes occurring during this step.

3. **Analyzing Statement C**:
- The statement claims that an ore may not be a mineral.
- **Evaluation**: This statement is incorrect. By definition, all ores are minerals, but not all minerals qualify as ores. An ore is a mineral that contains a valuable substance that can be extracted profitably.

**Hint**: Distinguish between minerals and ores; all ores are minerals, but not all minerals are ores.

4. **Analyzing Statement D**:
- The statement claims that Spallarite is an ore of Zinc.
- **Evaluation**: This statement is correct. Spallarite, represented as Zn, Fe, S, is indeed recognized as an ore of zinc.

**Hint**: Verify the chemical composition of minerals to confirm their status as ores.

### Conclusion:
After evaluating all the statements, the only correct statement is that Spallarite is an ore of Zinc. Therefore, the answer is **option D**.