The chemical formula of Prussian blue is formed by the reaction of ferric ion and ferrocyanide is

Options

A. `K_4[Fe(CN)_6]`
B. `Na_4[Fe(CN)_6]`
C. `Fe_4[Fe(CN)_6]_3`
D. None of these

Answer

To determine the chemical formula of Prussian blue formed by the reaction of ferric ion and ferrocyanide, we can follow these steps:

### Step 1: Identify the ions involved
- The ferric ion is represented as \( \text{Fe}^{3+} \).
- The ferrocyanide ion is represented as \( \text{[Fe(CN)_6]}^{4-} \).

### Step 2: Write the reaction
- When ferric ions react with ferrocyanide ions, the reaction can be represented as:
\[ \text{Fe}^{3+} + \text{[Fe(CN)_6]}^{4-} \rightarrow \text{Prussian blue} \]

### Step 3: Determine the formula of Prussian blue
- The product formed from the reaction of one ferric ion and one ferrocyanide ion is \( \text{Fe}_3[\text{Fe(CN)}_6]_2 \).
- This is because two ferrocyanide ions are needed to balance the three ferric ions, resulting in the formula:
\[ \text{Fe}_3[\text{Fe(CN)}_6]_2 \]

### Step 4: Simplify the formula
- The simplified formula for Prussian blue is often written as \( \text{Fe}_4[\text{Fe(CN)}_6] \) or \( \text{Fe}_3[\text{Fe(CN)}_6]_2 \), but it is commonly referred to as \( \text{Fe}_3[\text{Fe(CN)}_6]_2 \) in literature.

### Step 5: Conclusion
- Therefore, the chemical formula of Prussian blue formed by the reaction of ferric ion and ferrocyanide is \( \text{Fe}_3[\text{Fe(CN)}_6]_2 \).

### Final Answer
- The correct option is **C**.