Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.
Nitrogen, sulphur, and halogens are covalently bonded in organic compounds. For their detection, they have to be first converted to ionic form. This is done by fusing the organic compound with sodium metal. This is called “Lassaigne’s test”. The chemical equations involved in the test are
`Na + C + N -> NaCN`
`Na + S + C + N -> NaSCN`
`2Na + S -> Na_2S`
`Na + X -> NaX`
(X= Cl, Br, I)
Carbon, nitrogen, sulphur, and halogen come from organic compounds.
Organic compound is fused with sodium metal so as to convert organic compounds into NaCN, Na2S, NaX and Na3PO4. Since these are ionic compounds and become more reactive and thus can be easily tested by suitable reagents.