Notebook Theme

Experiment No. N

Analysis of Lead(II) Nitrate (Pb(NO₃)₂)

Aim

To determine the presence of anion and cation in the given salt

Preliminary Test

  • Odor: Odorless
  • Texture: Crystalline
  • Color: White
  • Solubility: Soluble in water

Test of Anion

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

ExperimentObservationInference
Original solution + Dilute HClWhite precipitatePb²⁺ may be present
Confirmatory Tests
Potassium Iodide Test
Dissolve one part of the hot precipitate in hot water and add potassium iodide solution
Yellow precipitate is formedPresence of Pb²⁺ is confirmed
Potassium Chromate Test
To the acidified solution obtained above, add potassium chromate solution
Yellow precipitate is formedPresence of Pb²⁺ is confirmed
Lead Sulphate Test
Dissolve lead sulphide precipitate in dilute HNO₃, then add a few drops of dilute H₂SO₄ and alcohol
White precipitate of lead sulphate is formedPresence of Pb²⁺ is confirmed

Result

The given salt contains Pb²⁺ ions as cation and NO₃⁻ ions as anion. The salt is Pb(NO₃)₂.

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.