Notebook Theme

Experiment No. N

Analysis of Lead(II) Chloride (Pb(Cl)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
Take 0.1 g of salt and add conc. H₂SO₄A colourless gas is evolved which gives dense white fumes with ammoniaCl⁻ may be present
Confirmatory Tests
Concentrated H₂SO₄ and MnO₂ Test
Take a pinch of MnO₂ in salt solution and add 3–4 drops of conc. H₂SO₄, then heat
Greenish yellow chlorine gas is evolvedPresence of Cl⁻ is indicated
Silver Nitrate Test
Acidify 1 mL of sodium carbonate extract with dilute HNO₃ (or use water extract) and add AgNO₃ solution
Curdy white precipitate soluble in NH₄OHCl⁻ is confirmed
Chromyl Chloride Test
Take a little salt with solid K₂Cr₂O₇, add conc. H₂SO₄, heat. Pass the evolved gas through sodium hydroxide solution, divide into two parts. Acidify one part with acetic acid and add lead acetate solution
The sodium hydroxide solution becomes yellow; adding acetic acid and lead acetate gives yellow precipitate of lead chromateCl⁻ 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 Cl⁻ ions as anion. The salt is Pb(Cl)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.