Notebook Theme

Experiment No. N

Analysis of Arsenic(III) Phosphate (AsPO₄)

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
Original solution + H₂S gas in presence of dil. HCl and NH₄ClYellow precipitate is formedGroup-II-B (As³⁺) may be present
Confirmatory Test
Ammonium Molybdate Test
Treat the dissolved precipitate with concentrated nitric acid and ammonium molybdate solution
Canary yellow precipitate is formedPresence of As³⁺ is confirmed

Result

The given salt contains As³⁺ ions as cation and PO₄³⁻ ions as anion. The salt is AsPO₄.

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.