Question

what is the process done in brown ring test?

Answer 1

brown ring test ( ferrous solution and conc. sulphuric acid)
To a little of solution an equal volume of freshly prepared ferrrous sulphate solution is added and shaken well. to this  conc. sulphuric acid  is carefully added along the sides of the test tube

observation
a brown ring is formed at the juction of the acid and aqueous solution

inference
prescence of nitrate is confirmed

Answer 2

The brown ring test is performed byputting iron(II) sulfate to a solution that contains nitrate ions. After that, slowly and carefully add concentrated sulphuric acid without disturbing the solution so that a sulphuric acid layer is formed under the aqueous solution. If nitrate is present, a brown ring consisting of [Fe(H2O)5NO]SO4 will form at the junction of the two layers.