Notebook Theme

Experiment No. N

Analysis of Iron(III) Fluoride (Fe(F)₃)

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 + NH₄OH solutionReddish-brown precipitateGroup-III cation may be present
Confirmatory Tests
Potassium Ferrocyanide Test
Dissolve the precipitate in dilute HCl, divide into two parts and add potassium ferrocyanide to one part
Blue/Prussian blue precipitateFe³⁺ is confirmed
Potassium Thiocyanate Test
To second part add potassium thiocyanate solution
Blood-red colouration is formedFe³⁺ is confirmed

Result

The given salt contains Fe³⁺ ions as cation and F⁻ ions as anion. The salt is Fe(F)₃.

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.