A: `FeCl_(3)`, reacts with KCNS to give blood red colour.
R: `FeCl_(3)`, reacts with KCNS to form potassium ferro-ferricyanide

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question, we need to analyze the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that `FeCl3` reacts with `KCNS` to give a blood red color.

- **Explanation**: Ferric chloride (`FeCl3`) reacts with potassium thiocyanate (`KCNS`) to form ferric thiocyanate (`Fe(SCN)3`), which is known to produce a blood red color in solution.

### Step 2: Understand the Reaction
The reaction can be represented as follows:
\[ FeCl_3 + 3 KCNS \rightarrow Fe(SCN)_3 + 3 KCl \]

- **Explanation**: In this reaction, one mole of ferric chloride reacts with three moles of potassium thiocyanate to produce one mole of ferric thiocyanate and three moles of potassium chloride.

### Step 3: Analyze the Reason
The reason states that `FeCl3` reacts with `KCNS` to form potassium ferro-ferricyanide.

- **Explanation**: This statement is incorrect. The product formed from the reaction of `FeCl3` and `KCNS` is ferric thiocyanate, not potassium ferro-ferricyanide. Potassium ferro-ferricyanide would involve cyanide ions (CN⁻), not thiocyanate ions (SCN⁻).

### Conclusion
- **Assertion**: True (FeCl3 reacts with KCNS to give a blood red color).
- **Reason**: False (It does not form potassium ferro-ferricyanide; it forms ferric thiocyanate).

### Final Answer
The assertion is true, but the reason is false.