Test for nitrates
It is also called as brown ring test.
In this we take test tube and sample (salt containing nitrate) to it.
- Then slowly pour concentrated sulphuric acid to it.
- Then we put solution of ferrous sulphate and allow it to stand.
- Then on interface a brown ring is formed that shows the presence of nitrates.
- The ring that is formed is chemically [Fe(H2O)5(NO)]2+(Nitroso ferrous sulphate ).