Which of the following statement is/are correct with reference to the ferrous and ferric ions?

Options

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

Explanation

To determine which statements are correct regarding ferrous (Fe²⁺) and ferric (Fe³⁺) ions, we need to analyze the reactions of these ions with specific reagents. Let's break down the statements provided:

### Step-by-Step Solution:

1. **Understanding the Ions**:
- **Ferrous Ion (Fe²⁺)**: This ion has a +2 oxidation state.
- **Ferric Ion (Fe³⁺)**: This ion has a +3 oxidation state.

2. **Analyzing Statement A**:
- **Statement A**: "Ferric ion gives brown color with potassium ferricyanide."
- **Analysis**: This statement is incorrect. Ferric ions do not produce a brown color with potassium ferricyanide. Instead, they react to form a different complex.

3. **Analyzing Statement B**:
- **Statement B**: "Ferrous ion gives blue precipitate with potassium ferricyanate."
- **Analysis**: This statement is correct. When ferrous ions react with potassium ferricyanide, they form a dark blue precipitate known as Turnbull's blue.

4. **Analyzing Statement C**:
- **Statement C**: "Ferric ion gives red color with potassium ferricyanide."
- **Analysis**: This statement is also correct. Ferric ions react with potassium ferricyanide to form a blood-red complex known as ferric ferricyanide.

5. **Analyzing Statement D**:
- **Statement D**: "Ferrous ion gives brown color with ammonium thiocyanate."
- **Analysis**: This statement is incorrect. Ferrous ions typically do not produce a brown color with ammonium thiocyanate. Instead, they form a different colored complex.

### Conclusion:
- The correct statements are:
- Statement B: Ferrous ion gives blue precipitate with potassium ferricyanide.
- Statement C: Ferric ion gives red color with potassium ferricyanide.

### Final Answer:
- **Correct Statements**: B and C.