Flame tests for metal ions

A/L Chemistry · G.C.E. Advanced Level · Grades 12–13

Aim

To identify metal ions from the colour they give to a flame.

Apparatus

• Nichrome wire loop
• Conc. HCl and metal salts
• Bunsen flame and cobalt-blue glass

Method

1. Clean the wire in conc. HCl and the flame.
2. Pick up a little salt and hold it in the flame.
3. Note the flame colour.
4. View through blue glass to hide the yellow.

Conclusion

Li⁺ crimson, Na⁺ golden yellow, K⁺ lilac, Ca²⁺ brick red, Sr²⁺ crimson, Ba²⁺ apple green, Cu²⁺ blue-green. Blue glass absorbs the yellow of Na⁺.