Lassaigne's test is used in the qualitative analysis to detect

Options

A. nitrogen
B. sulphur
C. chlorine
D. all of these.

Explanation

**Step-by-Step Solution:**

1. **Understanding Lassaigne's Test**: Lassaigne's test, also known as the sodium fusion test, is a qualitative analysis method used to detect the presence of certain elements in organic compounds.

2. **Elements Detected**: The test is specifically used to detect elements such as nitrogen, sulfur, and halogens (which include chlorine).

3. **Process of the Test**: In this test, the organic compound is fused with sodium metal. This fusion process converts the covalently bonded organic compound into ionic compounds, which allows for the detection of the elements.

4. **Sodium Fusion Extract**: After fusing the organic compound with sodium, a sodium fusion extract is prepared. This extract contains the ionic forms of the elements present in the original organic compound.

5. **Conclusion**: Since Lassaigne's test can detect nitrogen, sulfur, and halogens (including chlorine), the correct answer to the question is that it can detect all of these elements.

6. **Final Answer**: Therefore, the correct option is "all of these" (option 4).

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