2(h) Chemical tests

(h) Chemical tests
2.45 describe how to carry out a flame test
2.46 know the colours formed in flame tests for these cations:

  • Li+ is red
  • Na+ is yellow
  • K+ is lilac
  • Ca2+ is orange-red
  • Cu2+ is blue-green
2.47 describe tests for these cations:

  • NH4+ using sodium hydroxide solution and identifying the gas evolved
  • Cu2+, Fe2+ and Fe3+ using sodium hydroxide solution
2.48 describe tests for these anions:

  • Cl–, Br– and I– using acidified silver nitrate solution
  • SO42– using acidified barium chloride solution
  • CO32– using hydrochloric acid and identifying the gas evolved
2.49 describe a test for the presence of water using anhydrous copper(II) sulfate
2.50 describe a physical test to show whether a sample of water is pure