During Lassaigne's test S and N present in an organic compound change into :

Options

A. `Na_(2)S " and " NaCN`
B. `Na_(2) SO_(4) " and " NaCN`
C. `Na_(2)S " and " NaCNO`
D. `NaCN " and " NaCNO`

Explanation

### Step-by-Step Solution:

1. **Understanding Lassaigne's Test**:
Lassaigne's test is a qualitative analysis method used to detect the presence of certain elements (like sulfur and nitrogen) in organic compounds. The test involves heating the organic compound with sodium metal.

2. **Reaction of Sulfur**:
When sulfur (S) is present in an organic compound and it reacts with sodium (Na), it forms sodium sulfide (Na2S). The reaction can be represented as:
\[ S + 2Na \rightarrow Na2S \]
This indicates that two moles of sodium are required to convert sulfur into sodium sulfide.

3. **Reaction of Nitrogen**:
Similarly, when nitrogen (N) is present in the organic compound, it reacts with sodium and carbon (which is usually present in organic compounds) to form sodium cyanide (NaCN). The reaction can be represented as:
\[ N + Na + C \rightarrow NaCN \]
Here, one mole of sodium and one mole of carbon are required to convert nitrogen into sodium cyanide.

4. **Conclusion**:
Therefore, during Lassaigne's test, sulfur changes into sodium sulfide (Na2S) and nitrogen changes into sodium cyanide (NaCN). The correct answer to the question is that sulfur and nitrogen present in an organic compound change into Na2S and NaCN, respectively.