If on adding `FeCl_(3)` solution to acidified Lassaigne solution, a blood red colouration is produced, it indicates the presence of

Options

A. S
B. N
C. N and S
D. S and Cl

Explanation

To solve the question regarding the addition of FeCl₃ solution to acidified Lassaigne solution producing a blood red coloration, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Lassaigne's Test**:
- Lassaigne's test is used to detect the presence of nitrogen and sulfur in organic compounds. When an organic compound is heated with sodium, it forms sodium salts of the elements present in the compound.

2. **Reaction with Sodium**:
- When an organic compound containing nitrogen and sulfur is treated with sodium, it forms sodium thiocyanate (NaSCN) if nitrogen is present. The reaction can be summarized as:
\[ \text{Organic Compound} + \text{Na} \rightarrow \text{NaSCN} + \text{other products} \]

3. **Acidification**:
- The Lassaigne solution is then acidified (usually with hydrochloric acid) to prepare it for the next step.

4. **Addition of FeCl₃**:
- When FeCl₃ (ferric chloride) is added to the acidified Lassaigne solution, it reacts with sodium thiocyanate to form a complex:
\[ \text{Fe}^{3+} + \text{SCN}^- \rightarrow \text{Fe(SCN)}^{2+} \]
- This complex is known to produce a blood red coloration.

5. **Conclusion**:
- The appearance of a blood red coloration indicates the presence of both nitrogen and sulfur in the original organic compound. Therefore, the correct answer to the question is that it indicates the presence of nitrogen (N) and sulfur (S).

### Final Answer:
The blood red coloration indicates the presence of **nitrogen and sulfur** in the organic compound.

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