Answer
Lassaigne’s Test – Principle
Lassaigne fusion involves converting heteroatoms (such as nitrogen, sulfur, and halogens) in an organic compound into water-soluble sodium salts, which enables their qualitative detection. The typical conversions are:
- NaCN for carbon and nitrogen (C + N)
- Na₂S for sulfur (S)
- NaX (where X = Cl, Br, I) for halogens
These salts are then tested in aqueous solution to identify the corresponding elements.
Note: The CuO–carbon reduction is a metallurgical reaction and not related to the sodium fusion method. Therefore, it is excluded from Lassaigne’s test.