When `K_(4)[Fe(CN)_(6)]` is added to `FeCl_(3)`,the complex compound formed is:

Options

A. `Fe_(3)[Fe(CN_(6)]_(4)`
B. `Fe_(4)[Fe(CN)_(6)]_(3)`
C. `K_(2)[Fe(CN)_(6)]`
D. `K_(2)Fe_(3)[Fe(CN)_(6)]_(2)`

Answer

To solve the question, we need to analyze the reaction between potassium ferrocyanide and ferric chloride (FeCl₃) and identify the complex compound formed.

### Step-by-Step Solution:

1. **Identify the Reactants:**
The reactants in this reaction are:
- Potassium ferrocyanide: \( K_4[Fe(CN)_6] \)
- Ferric chloride: \( FeCl_3 \)

2. **Write the Reaction:**
When potassium ferrocyanide reacts with ferric chloride, the following reaction occurs:
\[ K_4[Fe(CN)_6] + 4FeCl_3 \rightarrow Fe_3[Fe(CN)_6] + 12KCl \]
Here, the potassium ions (K⁺) from potassium ferrocyanide combine with chloride ions (Cl⁻) to form potassium chloride (KCl).

3. **Determine the Complex Compound:**
The complex compound formed in this reaction is:
\[ Fe_3[Fe(CN)_6] \]
This compound is also known as ferriferrocyanide or Persian blue.

4. **Balance the Reaction:**
To balance the reaction, we note that:
- 4 moles of \( FeCl_3 \) react with 1 mole of \( K_4[Fe(CN)_6] \).
- This results in the formation of 1 mole of \( Fe_3[Fe(CN)_6] \) and 12 moles of \( KCl \).

5. **Conclusion:**
The complex compound formed when \( K_4[Fe(CN)_6] \) is added to \( FeCl_3 \) is \( Fe_3[Fe(CN)_6] \), commonly referred to as Persian blue.

### Final Answer:
The complex compound formed is \( Fe_3[Fe(CN)_6] \) (ferriferrocyanide or Persian blue).

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