The coordination compounds are of great importance. These compounds are widely present in the mineral, plant and animal worlds and are known to play many important functions in the area of analytical chemistry, metallurgy, biological systems, industry and medicine.
In which of the following processes, co-ordination complex formation/usage is done for extraction of metals ?

Options

A. Mc Artur Forrest cyanide process
B. Mond's process
C. Both (a) and (b)
D. None of these

Answer

To determine the processes in which coordination complex formation or usage is done for the extraction of metals, we will analyze the two mentioned processes: the McArthur Forest Cyanide Process and the Mound Process.

### Step-by-Step Solution:

1. **Understanding the McArthur Forest Cyanide Process**:
- This process is used for the extraction of gold and silver from their ores.
- It involves the use of sodium cyanide (NaCN) or potassium cyanide (KCN) to form a coordination complex with the metal ions.
- The reaction can be represented as follows:
\[ \text{Ag}_2\text{S} + 4 \text{NaCN} \rightleftharpoons 2 \text{Na}_2[\text{Ag(CN)}_2] + \text{S} \]
- Here, silver (Ag) forms a complex with cyanide ions, making it soluble in the solution, which allows for its extraction.

2. **Understanding the Mound Process**:
- The Mound Process is used for the extraction of nickel.
- In this process, nickel reacts with carbon monoxide (CO) to form nickel carbonyl (Ni(CO)₄), which is a volatile coordination complex.
- The reaction can be represented as:
\[ \text{Ni} + 4 \text{CO} \rightarrow \text{Ni(CO)}_4 \]
- Upon heating, nickel carbonyl decomposes to yield pure nickel and carbon monoxide:
\[ \text{Ni(CO)}_4 \rightarrow \text{Ni} + 4 \text{CO} \]
- This process effectively separates pure nickel from impurities.

3. **Conclusion**:
- Both the McArthur Forest Cyanide Process and the Mound Process involve the formation of coordination complexes for the extraction of metals (silver and nickel, respectively).
- Therefore, the correct answer to the question is that coordination complex formation is utilized in both processes.

### Final Answer:
Both A (McArthur Forest Cyanide Process) and B (Mound Process) are correct options for the extraction of metals through coordination complex formation.