Flame Tests (Edexcel IGCSE Chemistry: Double Science)

• The flame test is used to identify the positive metal ion (cations) by the colour of the flame they produce
  • Ions from different metals produce different colours
• To carry out a flame test:
  • Dip the loop of an unreactive metal wire such as nichrome or platinum in dilute acid
  • Hold it in the blue flame of a Bunsen burner until there is no colour change
  • Dip the loop into the solid sample / solution and place it in the edge of the blue Bunsen flame
• It is important to place the wire into acid first to prevent contamination
  • Not doing this might result in two or more ions being present on the wire meaning the colours will mix
  • One colour could mask another colour and you will not be able to identify the ion

Diagram showing the technique for carrying out a flame test

• The colour of the flame is observed and used to identify the metal ion present

Diagram showing the colours formed in the flame test for metal ions