Question

In Lassaigne's test, the organic compound is fused with a piece of sodium metal in order to:

• A. increase the ionisation of the compound
• B. decrease the melting point of the compound
• C. increase the reactivity of the compound
• D. convert the covalent compound into a mixture of ionic compounds

Answer 1

The correct option is D convert the covalent compound into a mixture of ionic compounds

Lassaigne's test is a general test for the detection of halogens, nitrogen and sulphur in an organic compound. These elements are covalently bonded to the organic compounds. In order to detect them, these have to be converted into their ionic forms. This is done by fusing the organic compound with sodium metal. The ionic compounds formed during the fusion are extracted in aqueous solution and can be detected by simple chemical tests. The extract is called sodium fusion extract or Lassaigne's extract.