In the cyanide extraction process of silver form argentite ore , the oxidizing and reducing agents used are

Options

A. `O_2` and `CO_2`
B. `O_2` and Zn dust
C. `HNO_3` and `CO`
D. `HNO_3` and Zn dust

Explanation

To solve the question regarding the oxidizing and reducing agents used in the cyanide extraction process of silver from argentite ore, we can break down the process into clear steps:

### Step-by-Step Solution:

1. **Understanding the Ore**:
- Argentite ore primarily contains silver sulfide (Ag2S). The first step in the cyanide extraction process involves the reaction of silver sulfide with cyanide ions.

2. **Reaction with Cyanide**:
- The silver sulfide (Ag2S) reacts with cyanide ions (CN⁻) in the presence of oxygen (O2).
- This reaction produces a silver cyanide complex (Ag(CN)2⁻) and sulfur dioxide (SO2) gas.
- The chemical equation for this reaction can be represented as:
\[ \text{Ag}_2\text{S} + 4\text{CN}^- + \text{O}_2 \rightarrow 2\text{Ag(CN)}_2^- + \text{SO}_2 \]

3. **Identifying the Oxidizing Agent**:
- In this reaction, silver sulfide (Ag2S) is oxidized to sulfur dioxide (SO2).
- Since oxygen (O2) facilitates this oxidation, it acts as the oxidizing agent.

4. **Reduction of Silver**:
- In the next step, the silver cyanide complex (Ag(CN)2⁻) is treated with zinc dust (Zn).
- This reaction results in the formation of pure silver (Ag) and zinc cyanide (Zn(CN)4²⁻).
- The equation for this reaction can be represented as:
\[ \text{Ag(CN)}_2^- + \text{Zn} \rightarrow \text{Ag} + \text{Zn(CN)}_4^{2-} \]

5. **Identifying the Reducing Agent**:
- In this step, silver (Ag) is reduced from an oxidation state of +1 in the silver cyanide complex to 0 in its elemental form.
- Zinc dust (Zn) donates electrons to facilitate this reduction, thus acting as the reducing agent.

6. **Final Conclusion**:
- Therefore, in the cyanide extraction process of silver from argentite ore, the oxidizing agent is oxygen (O2) and the reducing agent is zinc dust (Zn).

### Final Answer:
The oxidizing and reducing agents used in the cyanide extraction process of silver from argentite ore are:
- **Oxidizing Agent**: Oxygen (O2)
- **Reducing Agent**: Zinc dust (Zn)