What colour flame would lithium ions produce?

Name a metal ion that would produce a lilac flame.

Some solutions contain a mixture of metal ions. Why is it difficult to identify individual metal ions from just the colour of the flame?

Flame emission spectroscopy is used to identify metal ions.

![A diagram of five reference flame emission spectra and a mixture spectrum on a scale from 400 to 750 nm.

• ${Ca}^{2+}$ has emission lines at 450, 550, and 650 nm.
• ${Cu}^{2+}$ has emission lines at 500 and 580 nm.
• $K^{+}$ has emission lines at 404 and 690 nm.
• ${Li}^{+}$ has an emission line at 671 nm.
• ${Na}^{+}$ has an emission line at 589 nm.
• The mixture spectrum of two metal ions has lines at 404, 500, 580, and 690 nm.](https://assets.mathsgenie.co.uk/aqa-qb/2e88df86-0e27-4744-8eb7-464e4f6ba0a3.png)

Which two metal ions are in the mixture?

Silver nitrate solution and dilute nitric acid are added to a solution of chemical salts. A yellow precipitate forms. Which ion is shown to be present by this test?

Describe a test to show the presence of carbonate ions in a solution. Give the result of the test if carbonate ions are present.