Question

Brown ring in the ring test for nitrate is due to the formation of

Answer 1

The brown ring test is a common nitrate test.

The reaction equations are as follows:

2HNO3 + 3H2SO4 + 6FeSO4 → 3Fe2(SO4)3 + 2NO + 4H2O

[Fe(H2O)]SO4 + NO → [Fe(H2O)5(NO)]SO4 + H2O

[Fe(H2O)5(NO)]SO4 ----->Pentaquo nitrosyl iron(II) sulphate. The brown ring complex.