In the cyanide process involving extraction of silver, zinc is used industrially as:-

Options

A. Oxidising agent
B. Reducing agent
C. Solvent
D. Solvating agent

Answer

To solve the question regarding the role of zinc in the cyanide process for the extraction of silver, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Cyanide Process**:
The cyanide process, also known as the cyanidation process, is used for the extraction of precious metals like silver and gold. In this process, the metal is converted into a soluble complex with cyanide ions.

2. **Reaction Involving Silver and Cyanide**:
The initial reaction can be represented as:
\[ 4 \text{Ag} + 8 \text{NaCN} + \text{O}_2 + 2 \text{H}_2\text{O} \rightarrow 4 \text{NaAg(CN)}_2 + 4 \text{NaOH} \]
Here, silver (Ag) is oxidized and forms a soluble complex with cyanide ions.

3. **Role of Zinc in the Process**:
Zinc is introduced in the process to reduce the silver from its complex. The reaction can be represented as:
\[ \text{NaAg(CN)}_2 + \text{Zn} \rightarrow \text{Na}_2\text{Zn(CN)}_4 + \text{Ag} \]
In this reaction, zinc displaces silver from the complex.

4. **Determining the Oxidation States**:
To understand the role of zinc, we need to analyze the oxidation states:
- In the reactant, zinc has an oxidation state of 0.
- In the product \(\text{Na}_2\text{Zn(CN)}_4\), we can calculate the oxidation state of zinc:
- The overall charge of the compound is neutral (0).
- The sodium (Na) has a +1 charge, and the cyanide (CN) has a -1 charge.
- Setting up the equation:
\[ 2(+1) + x + 4(-1) = 0 \implies x - 2 = 0 \implies x = +2 \]
- Thus, zinc in \(\text{Na}_2\text{Zn(CN)}_4\) has an oxidation state of +2.

5. **Conclusion on Zinc's Role**:
Since zinc goes from an oxidation state of 0 to +2, it loses electrons during the reaction. This loss of electrons indicates that zinc is undergoing oxidation. Therefore, zinc acts as a reducing agent in this reaction.

### Final Answer:
Zinc is used industrially as a **reducing agent** in the cyanide process for the extraction of silver.

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