Notebook Theme

Analysis of Potassium Acetate (KCH₃COO)

Qualitative analysis

Aim

To analyse the given inorganic salt for one acidic and one basic radical.

Preliminary Test

  • Colour: White
  • Odour: Vinegar-like
  • State: Crystalline solid
  • Solubility: Soluble in water

Test of Anion (CH₃COO⁻)

ExperimentObservationInference
Take 0.1 g salt + dilute H₂SO₄Colourless vapours with vinegar-like smell evolveCH₃COO⁻ may be present
Confirmatory Tests
Ester Test
Take 0.1 g salt in a test tube with ethanol and a little conc. H₂SO₄, then heat
Fruity odour of ethyl acetate is developedCH₃COO⁻ is confirmed
Ferric Chloride Test
Add neutral ferric chloride solution to the salt solution
Deep red colour appears; on heating it disappears and a brown-red precipitate formsCH₃COO⁻ is confirmed

Test of Cation (K⁺)

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⁺ as the cation (basic radical) and CH₃COO⁻ as the anion (acidic radical). The salt is Potassium Acetate (KCH₃COO).

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.