Question

Give a systematic procedure to carry out the brown ring test in a laboratory.

Answer 1

• Take a small amount of the aqueous salt solution containing the nitrate ion in a clean test tube.
• Add an equal volume of a freshly prepared saturated solution of iron(II) sulphate (FeSO₄).
• Incline the test tube at an angle and carefully add concentrated sulphuric acid (H₂SO₄) along the inner side of the tube so that it forms a separate lower layer.
• A distinct brown ring forms at the junction of the two liquid layers.