Which of the following statement(s) is (are) incorrect ?

Options

A. `Fe^(2+)` ions give a dark blue precipitate with potassium hexacyanidoferrate `(III)` solution.
B. `Fe^(3+)` ions give intense blue precipitate with potassium hexacyanidoferrate `(II)` solution.
C. `Fe^(3+)` ions give a brown colouration with potassium hexacyanidoferrate `(III)` solution.
D. `Fe^(2+)` ions give a deep red colouration with ammonium thicyanate.

Explanation

To determine which of the statements regarding iron ions and their reactions are incorrect, we will analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement:** Fe²⁺ ions give a dark blue precipitate with potassium hexacyanidoferrate(III) solution.

**Analysis:** This statement is true. When Fe²⁺ ions react with potassium hexacyanidoferrate(III), they form a dark blue precipitate known as Turnbull's blue.

### Step 2: Analyze the second statement
**Statement:** Fe³⁺ ions give an intense blue precipitate with potassium hexacyanidoferrate(II) solution.

**Analysis:** This statement is also true. The reaction of Fe³⁺ ions with potassium hexacyanidoferrate(II) produces a deep blue precipitate known as Prussian blue.

### Step 3: Analyze the third statement
**Statement:** Fe³⁺ ions give a brown coloration with potassium hexacyanidoferrate(III) solution.

**Analysis:** This statement is true. The reaction of Fe³⁺ ions with potassium hexacyanidoferrate(III) typically results in a brown precipitate.

### Step 4: Analyze the fourth statement
**Statement:** Fe²⁺ ions give a deep red coloration with ammonium thiocyanate.

**Analysis:** This statement is incorrect. Fe²⁺ ions do not react with ammonium thiocyanate to produce a deep red coloration. Instead, it is Fe³⁺ ions that react with ammonium thiocyanate to form a deep red complex.

### Conclusion
Based on the analysis:
- The first, second, and third statements are true.
- The fourth statement is incorrect.

### Final Answer
The incorrect statement is: "Fe²⁺ ions give a deep red coloration with ammonium thiocyanate."

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