Notebook Theme

Analysis of Sodium Nitrate (NaNO₃)

Qualitative analysis

Aim

To analyse the given inorganic salt for one acidic and one basic radical.

Preliminary Test

  • Colour: White
  • Odour: Odourless
  • State: Crystalline solid
  • Solubility: Soluble in water

Test of Anion (NO₃⁻)

ExperimentObservationInference
Add conc. H₂SO₄ to the solution and boil with a few copper turnings/chipsOn heating, brown fumes (NO₂) are evolved in excess and the solution becomes blueNO₃⁻ may be present
Confirmatory Test
Brown Ring Test
Take 1 mL of salt solution, add 2 mL conc. H₂SO₄, cool, then add freshly prepared ferrous sulphate solution along the sides
Brown ring is formed at the junction of the two solutionsNO₃⁻ is confirmed

Test of Cation (Na⁺)

ExperimentObservationInference
Flame test in a clean non-luminous flameIntense yellow flameNa⁺ may be present
Confirmatory Test
Zinc Uranyl Acetate Test
Take a filtrate and add zinc uranyl acetate solution
Yellow crystalline precipitateNa⁺ is confirmed

Result

The given salt contains Na⁺ as the cation (basic radical) and NO₃⁻ as the anion (acidic radical). The salt is Sodium Nitrate (NaNO₃).

Precautions

  1. Handle the chemicals with care.
  2. Don't use excess of chemicals.
  3. Keep the mouth of the test tube away from the face.