ion testing

• testing for cation

  • flame test
  • lithium - Li+ - crimson red flame
  • sodium - Na+ - yellow flame
  • potassium - K+ - lilac flame
  • calcium - Ca2+ - orange red flame
  • copper - Cu2+ - blue green flame
• testing for cations

  • sodium hydroxide test
  • aluminium - Al3+ - white ppt
  • calcium - Ca2+ - white ppt
  • copper - Cu2+ - blue ppt
  • iron - Fe2+ - green ppt
  • iron - Fe3+ - orange brown ppt
• testing for ammonium ions

  • add sodium hydroxide
  • gently heat
  • place damp red litmus
  • is ammonia gas present litmus turns blue
  • pungent smell
• testing for anions

  testing for halide

  • add few drops nitric acid - remove other ions
  • possible halide solution + silver nitrate
  • chloride ion - white ppt
  • bromide ion - cream ppt
  • iodide ion - yellow ppt
• testing for anions

  • testing for sulfate ions
  • and HCl - remove other ions
  • add barium chloride
  • if white ppt formed sulfate is present
• testing for anions

  • testing for carbonate ions
  • add acid to solution
  • bubble produced gas through lime water
  • if becomes cloudy carbonate ions present
• flame photometry

  • improves , sensitivity , speed , accuracy
  • separates mixture of colours in a flame to produce a spectra of lights emitted by each metal ion