Notebook Theme

Analysis of Sodium Sulfate (Na₂SO₄)

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 (SO₄²⁻)

ExperimentObservationInference
Confirmatory Tests
If no earlier anion test is positive, acidify the extract with dilute HCl and add BaCl₂ solutionWhite precipitate of barium sulphate, insoluble in conc. HCl or conc. HNO₃ is obtainedSO₄²⁻ may be present
Lead Acetate Test
Acidify the solution with acetic acid and add lead acetate solution
White precipitate appearsPresence of SO₄²⁻ 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 SO₄²⁻ as the anion (acidic radical). The salt is Sodium Sulfate (Na₂SO₄).

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.