Copper is the most noble of first row transition metals and occurs in small deposits in serveral countries. Ores of copper include chalcanthite `(CuSO_(4).5H_(2)O)`, atacanite `[Cu_(2)Cl(OH)_(3)]`, cuprite `(Cu_(2)O)`, copper glance `(Cu_(2)S)`, and malachite `[Cu_(2)(OH)_(2)CO_(3)]`. However, `80 %` of the world copper production comes from the ore chalcopyrite `(CuFeS_(2))`. The extraction of copper from chalcopyrite involves partial roasting, removal of iron and self-reduction.
In self-reduction, the reducing species is.

Options

A. S
B. `O^(2-)`
C. `S^(2-)`
D. `SO_(2)`

Explanation

To determine the reducing species in the self-reduction process during the extraction of copper from chalcopyrite (CuFeS₂), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Process**: The extraction of copper from chalcopyrite involves several steps, including partial roasting, removal of iron, and self-reduction. We need to focus on the self-reduction part.

2. **Understand Self-Reduction**: In self-reduction, two compounds of copper interact with each other. The two main compounds involved in this process are cuprous oxide (Cu₂O) and cuprous sulfide (Cu₂S).

3. **Write the Reaction**: The self-reduction reaction can be represented as:
\[ 2 \text{Cu}_2\text{S} + \text{Cu}_2\text{O} \rightarrow 6 \text{Cu} + 2 \text{SO}_2 \]
In this reaction, cuprous sulfide (Cu₂S) and cuprous oxide (Cu₂O) react to produce copper (Cu) and sulfur dioxide (SO₂).

4. **Determine Oxidation States**:
- In Cu₂S, the oxidation state of sulfur is -2.
- In SO₂, the oxidation state of sulfur is +4.
- Therefore, sulfur is oxidized from -2 to +4, indicating that it loses electrons.

5. **Identify the Reducing Species**: The species that gets oxidized (loses electrons) is the reducing agent. In this case, the sulfide ion (S²⁻) in Cu₂S is oxidized to sulfur dioxide (SO₂), thus acting as the reducing species.

6. **Conclusion**: The reducing species in the self-reduction process is the sulfide ion (S²⁻).

### Final Answer:
The reducing species in self-reduction is the sulfide ion (S²⁻).

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