Which of the following is involved in the extraction of Ag from argentite ?

Options

A. `[Ag(NH_3)_2]^(+)`
B. `[Ag(SCN)_4]^(3)`
C. `[Ag(CN)_2]^(-)`
D. `[Ag Cl_2]^(-)`

Answer

To solve the question regarding the extraction of silver (Ag) from argentite (Ag2S), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Ore**: Argentite is the mineral from which silver is extracted. Its chemical formula is Ag2S (silver sulfide).

2. **Chemical Reaction with Sodium Cyanide**: The extraction process involves treating argentite with sodium cyanide (NaCN). The reaction can be represented as:
\[ \text{Ag}_2\text{S} + 4 \text{NaCN} \rightarrow 2 \text{NaAg(CN)}_2 + \text{Na}_2\text{S} \]
Here, sodium cyanide reacts with argentite to form sodium argento cyanide (NaAg(CN)2), which is soluble in water.

3. **Filtration**: The solution containing the soluble sodium argento cyanide is then filtered to remove any insoluble impurities.

4. **Precipitation of Silver**: The filtered solution is treated with zinc (Zn), which reduces the silver ions and precipitates silver metal. The reaction can be represented as:
\[ 2 \text{NaAg(CN)}_2 + \text{Zn} \rightarrow \text{Na}_2\text{Zn(CN)}_4 + 2 \text{Ag} \downarrow \]
In this reaction, silver is precipitated out of the solution.

5. **Conclusion**: The compound involved in the extraction of silver from argentite is sodium argento cyanide (NaAg(CN)2), which is formed during the initial reaction with sodium cyanide.

### Final Answer:
The correct answer is option C: **NaAg(CN)2** is involved in the extraction of Ag from argentite.

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