Question

Nitrate is confirmed by ring test. The brown colour of the ring test is due to the formation of

Answer 1

FeSO4.NO
A nitrate test is a chemical test used to determine the presence of nitrate ion in solution. A common nitrate test, known as the brown ring test can be performed by adding iron(II) sulfate to the solution, then slowly adding concentrated sulfuric acid (NOT nitric acid, since it gives nitrate ion which gives a positive result anyway) and watching for a brown ring on the test tube, which will indicate the presence of the nitrate ion. Note that the presence of nitrite ions will interfere with this test.