Notebook Theme

Experiment No. N

Analysis of Lead(II) Fluoride (Pb(F)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 the salt and treat with concentrated H₂SO₄Colourless gas evolves and it etches glassF⁻ may be present
Confirmatory Test
Calcium Chloride Test
Treat salt solution with calcium chloride solution
White gelatinous precipitate formsPresence of F⁻ 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 F⁻ ions as anion. The salt is Pb(F)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.