Testing Cations
Chemistry: Cambridge International GCSE Supplement, topic 12.5.4
Testing Cations
You can test solid cations using flame tests. The test allows you to identify the metal ions present in a single ionic compound.
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Flame test practical
- Clean a nichrome wire loop by submerging (completely covering) it in dilute hydrochloric acid.
- Dip the wire loop into the sample to be tested.
- Hold the wire loop in the blue flame of a Bunsen burner.
- Record the colour of the Bunsen flame.
Flame test practical
Results
- Lithium ions (Li+) will burn with a crimson flame.
- Sodium ions (Na+) will burn with a yellow flame.
- Potassium ions (K+) will burn with a lilac flame.
- Copper (II) ions (Cu2+) will burn with a green flame.
Test yourself on Testing Cations
A flame test is completed and a crimson flame is produced. What ions are present in the compound?
A flame test is completed and a green flame is produced. What ions are present in the compound?