Which of the following statement is correct?

Options

A. `Fe^(2+)` gives brown colour with ammonium thiocyanate
B. `Fe^(2+)` gives blue precipitate with potassium ferricyanide
C. `Fe^(3+)` gives brwon colour with potassium ferrocyanide
D. `Fe^(3+)` gives red colour with potassium ferrocyanide

Answer

To determine which statement is correct regarding the reactions of iron ions with various reagents, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement 1: Fe²⁺ gives brown color with ammonium thiocyanate.**
- **Analysis**: When Fe²⁺ reacts with ammonium thiocyanate (NH₄SCN), it forms a complex ion, but this complex is typically red, not brown. Therefore, this statement is **incorrect**.

2. **Statement 2: Fe²⁺ gives blue precipitate with potassium ferricyanide.**
- **Analysis**: When Fe²⁺ reacts with potassium ferricyanide (K₃[Fe(CN)₆]), it forms a blue precipitate known as Turnbull's blue (Fe₃[Fe(CN)₆]₂). Therefore, this statement is **correct**.

3. **Statement 3: Fe³⁺ gives brown color with potassium ferrocyanide.**
- **Analysis**: When Fe³⁺ reacts with potassium ferrocyanide (K₄[Fe(CN)₆]), it forms a blue precipitate known as Prussian blue (Fe₃[Fe(CN)₆]₂). Therefore, this statement is **incorrect**.

4. **Statement 4: Fe³⁺ gives red color with potassium ferrocyanide.**
- **Analysis**: When Fe³⁺ reacts with potassium ferrocyanide, it does not give a red color; instead, it also forms a blue precipitate (Prussian blue). Therefore, this statement is **incorrect**.

### Conclusion:
The only correct statement is **Statement 2**: "Fe²⁺ gives blue precipitate with potassium ferricyanide."

### Final Answer:
- The correct statement is: **Fe²⁺ gives blue precipitate with potassium ferricyanide.**