Gold is leached using `CN^(-)` solution followed by reduction with Zn. What is the co - ordination numberof Zn in the final product ?

Options

A. 2
B. 6
C. 5
D. 4

Answer

To determine the coordination number of zinc in the final product formed after the leaching of gold with cyanide and subsequent reduction with zinc, we can follow these steps:

### Step 1: Understand the leaching process
Gold is leached using cyanide ions (CN⁻). In this process, gold forms a complex with cyanide ions. The complex formed is [Au(CN)₂]⁻.

### Step 2: Identify the reduction process
After the formation of the gold-cyanide complex, zinc (Zn) is used to reduce this complex. The reaction can be represented as:
\[ 2Au(CN)₂⁻ + Zn \rightarrow 2Au + Zn(CN)₄²⁻ \]

### Step 3: Analyze the final product
The final product after the reduction is the zinc cyanide complex, which is Zn(CN)₄²⁻.

### Step 4: Determine the coordination number
To find the coordination number of zinc in the complex Zn(CN)₄²⁻, we need to consider the nature of the ligands:
- Cyanide (CN⁻) is a monodentate ligand, meaning it can form one bond with the central metal atom (Zn in this case).

### Step 5: Count the number of ligands
In the complex Zn(CN)₄²⁻, there are 4 cyanide ligands coordinated to zinc.

### Conclusion
The coordination number of zinc in the complex Zn(CN)₄²⁻ is equal to the number of ligands, which is 4.

Thus, the final answer is:
**The coordination number of Zn in the final product is 4.**

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