The chemical composition of slag formed during the smelting process in the extraction of copper is

Options

A. `Cu_(2)O + FeS`
B. `FeSiO_(3)`
C. `CuFeS_(2)`
D. `Cu_(2)S + FeO`

Explanation

### Step-by-Step Solution:

1. **Identify the Process**: The question pertains to the smelting process during the extraction of copper, specifically the formation of slag.

2. **Understand the Raw Materials**: In the extraction of copper, concentrated sulphide ore (which contains copper and iron as impurities) is used. The presence of iron is significant because it will contribute to the slag formation.

3. **Mix with Silica**: During the smelting process, the concentrated sulphide ore is mixed with silica (SiO2). This is an essential step as silica acts as a flux.

4. **Heating in a Reverberatory Furnace**: The mixture of concentrated ore and silica is heated in a reverberatory furnace. This high-temperature environment facilitates the chemical reactions needed to separate the desired metal from impurities.

5. **Conversion of Iron Sulfide**: As the mixture is heated, most of the iron sulfide (FeS) present in the ore is converted into iron oxide (FeO).

6. **Formation of Slag**: The iron oxide (FeO) then reacts with the silica (SiO2) to form a compound known as iron silicate. The chemical reaction can be represented as:
\[ \text{FeO} + \text{SiO}_2 \rightarrow \text{FeSiO}_3 \]

7. **Conclusion**: The slag formed during this smelting process is primarily composed of iron silicate, which is represented by the chemical formula FeSiO3.

### Final Answer:
The chemical composition of slag formed during the smelting process in the extraction of copper is **FeSiO3** (iron silicate).

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