Question

how is nitrogen detected in the organic compounds? Write the equation for the chemical reactions involved.

Answer 1

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