Question

During halogen test, sodium fusion extract is boiled with concentrated $HN{O}_3$ to

Answer 1

Nitrogen, Sulphur, and halogens present in organic compounds are detected by Lassaigne’s test. Here, a small piece of Na metal is heated in a fusion tube with the organic compound. The principle is that, in doing so, Na converts all the elements present into ionic form.

• Na + C + N → NaCN
• 2Na + S → Na₂S
• Na + X → NaX ( X= Cl, Br, or I)

The formed ionic salts are extracted from the fused mass by boiling it with distilled water. This is called sodium fusion extract.

During test for halogen, if nitrogen or sulphur is also present in the compound, then sodium fusion extract is first boiled with concentrated nitric acid to decompose cyanide or sulphide of sodium formed during Lassaigne's test.