Notebook Theme

Experiment No. N

Analysis of Potassium Phosphate ((K)₃PO₄)

Aim

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

Preliminary Test

  • Odor: Odorless
  • Texture: Crystalline
  • Color: White
  • Solubility: Slightly soluble in water

Test of Anion

ExperimentObservationInference
Confirmatory Test
Ammonium Molybdate Test
Acidify with conc. HNO₃ and add ammonium molybdate solution, boil
Canary yellow precipitate is formedPO₄³⁻ is confirmed

Test of Cation

ExperimentObservationInference
Flame test in a clean non-luminous flameLilac flameK⁺ may be present
Confirmatory Test
Sodium Cobaltinitrite Test
Salt solution + sodium cobaltinitrite reagent
Yellow precipitateK⁺ is confirmed

Result

The given salt contains K⁺ ions as cation and PO₄³⁻ ions as anion. The salt is (K)₃PO₄.

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.