Which one the following reactions does not occur during extraction of copper?

Options

A. `CaO + SiO_2`→` CaSiO_3`
B. `2 Cu_2S + 3 O_2 `→`2 Cu_2O + 2 SO_2`
C. `FeO + SiO_2 `→`FeSiO_3`
D. `2 FeS + 3 O_2 `→`2 FeO + 2 SO_2`

Answer

To determine which reaction does not occur during the extraction of copper, let's analyze the typical steps involved in the extraction process.

### Step-by-Step Solution:

1. **Understanding the Extraction Process**:
- Copper is primarily extracted from its ores, such as chalcopyrite (CuFeS₂). The extraction process involves several steps, including roasting, smelting, and refining.

2. **Roasting of Chalcopyrite**:
- The first step is the roasting of chalcopyrite (CuFeS₂) in the presence of oxygen. This partial roasting leads to the formation of copper(I) sulfide (Cu₂S), iron(II) oxide (FeO), and sulfur dioxide (SO₂).
- The reaction can be represented as:
\[ 2CuFeS_2 + 3O_2 \rightarrow 2Cu_2S + 2FeO + 2SO_2 \]

3. **Oxidation of Copper(I) Sulfide**:
- The next step involves the oxidation of copper(I) sulfide (Cu₂S) to produce copper metal and sulfur dioxide. The reaction is:
\[ 2Cu_2S + 3O_2 \rightarrow 4Cu + 2SO_2 \]

4. **Formation of Slag**:
- The iron(II) oxide (FeO) produced during roasting reacts with silica (SiO₂) to form slag, which is primarily calcium silicate (CaSiO₃). The reaction is:
\[ FeO + SiO_2 \rightarrow FeSiO_3 \quad (\text{slag}) \]

5. **Identifying the Reaction Not Involved**:
- The question asks for a reaction that does not occur during the extraction of copper. From the information provided, the formation of calcium silicate (CaSiO₃) does not occur in the extraction of copper. Instead, iron silicate (FeSiO₃) is formed as slag.

### Conclusion:
The reaction that does not occur during the extraction of copper is the formation of calcium silicate (CaSiO₃). Therefore, the correct answer is option 1.

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