Discuss and give chemical reaction of Lassaigne Test for
1. Nitrogen in the organic compound.
2. Nitrogen and Sulphur, both in the organic compound.
Discuss and give chemical reaction of Lassaigne Test for
1. Nitrogen in the organic compound.
2. Nitrogen and Sulphur, both in the organic compound.
Test for Nitrogen: The carbon and nitrogen present in the organic compound on fusion with sodium metal gives sodium cyanide (NaCN) soluble in water. This is converted in to sodium ferrocyanide by the addition of sufficient quantity of ferrous sulphate. Ferric ions generated during the process react with ferrocyanide to form prussian blue precipitate of ferric ferrocyanide.
Na + C + N → NaCN
6NaCN + FeSO4 → Na4[Fe(CN)6] + Na2SO4
Sodium ferrocyanide
Na4[Fe(CN)6] + Fe3+ → Fe4[Fe(CN)6]3
Ferric ferrocyanide
Test for both Nitrogen and Sulphur: If both nitrogen and sulphur are present in an organic compound, sodium fusion will convert it into sodium thiocyanate which then react with Fe3+ to form blood colour complex [Fe(SCN)]2+
Na + C + N + S → NaSCN
Fe3+ + 2Na → [Fe(SCN)]2+
The carbon and nitrogen present in the organic compound on fusion with sodium metal gives sodium cyanide (NaCN) soluble in water. This is converted in to sodium ferrocyanide by the addition of sufficient quantity of ferrous sulphate. Ferric ions generated during the process react with ferrocyanide to form prussian blue precipitate of ferric ferrocyanide.
Na + C + N → NaCN
6NaCN + FeSO4 → Na4[Fe(CN)6] + Na2SO4
Sodium ferrocyanide
Na4[Fe(CN)6] + Fe3+ → Fe4[Fe(CN)6]3
Ferric ferrocyanide
Test for both Nitrogen and Sulphur:
If both nitrogen and sulphur are present in an organic compound, sodium fusion will convert it into sodium thiocyanate which then react with Fe3+ to form blood colour complex [Fe(SCN)]2+
Na + C + N + S → NaSCN
Fe3+ + 2Na → [Fe(SCN)]2+
