`Ag_(2)S + NaCN + Zn" = "Ag`
This method of extraction of Ag by complex formation and then its displacement is called

Options

A. Parke's method
B. McArthur - Forest method
C. Serpeck method
D. Hall's method

Answer

To solve the question regarding the extraction of silver from its ore \( \text{Ag}_2\text{S} \) using sodium cyanide and zinc, we can break down the process step by step.

### Step-by-Step Solution:

1. **Identify the Ore and Reactants**:
- The ore of silver is \( \text{Ag}_2\text{S} \) (silver sulfide).
- The reactants involved in the extraction process are sodium cyanide (\( \text{NaCN} \)) and zinc (\( \text{Zn} \)).

2. **Complex Formation**:
- The first step in the extraction process involves the reaction of silver sulfide with sodium cyanide. This reaction leads to the formation of a complex:
\[ \text{Ag}_2\text{S} + 4 \text{NaCN} \rightarrow 2 \text{Na[Ag(CN)}_2] + \text{Na}_2\text{S} \]
- Here, \( \text{Na[Ag(CN)}_2] \) is the complex formed, and sodium sulfide (\( \text{Na}_2\text{S} \)) is produced as a byproduct.

3. **Displacement Reaction**:
- In the second step, the complex formed reacts with zinc. Zinc displaces silver from the complex:
\[ 2 \text{Na[Ag(CN)}_2] + \text{Zn} \rightarrow 2 \text{NaCN} + \text{Zn[Ag(CN)}_4] + 2 \text{Ag} \]
- In this reaction, zinc displaces silver, resulting in the formation of sodium cyanide and the zinc complex, while silver metal (\( \text{Ag} \)) is produced.

4. **Conclusion**:
- The overall process involves complex formation followed by displacement, which is characteristic of the cyanide process for extracting silver.
- This method is specifically known as the **MacArthur-Forrest method**.

### Final Answer:
The method of extraction of silver by complex formation and then its displacement is called the **MacArthur-Forrest method**.