(4.8.3)(Identification of ions by chemical and spectroscopic means)

How are the two ways to identify metal ions (cations)?

Using a flame test.

OR

Sodium hydroxide solutions.

Which metals can be tested for with a flame test?

Lithium, sodium, potassium, calcium and copper compounds.

What colour is produced for a flame test with lithium?

Crimson flame.

What colour is produced for a flame test with sodium?

Yellow flame.

What colour is produced for a flame test with potassium?

Lilac flame.

What colour is produced for a flame test with calcium?

Orange-red flame.

What colour is produced for a flame test with copper?

Green flame.

Which solutions produce precipitate when added to sodium hydroxide?

Solutions of aluminium, calcium and magnesium ions.

Which solutions produce a coloured precipitate when added to sodium hydroxide?

Copper(II), iron(II) and iron(III) ions.

What colour precipitate is made when copper (II) is added to sodium hydroxide?

Blue precipitate.

What colour precipitate is made when iron (II) is added to sodium hydroxide?

Green precipitate.

What colour precipitate is made when iron (III) is added to sodium hydroxide?

Brown precipitate.

When carbonates react with dilute acids what gas is produced?

Carbon dioxide.

Halide ions produce precipitates with what solutions in the presence of dilute nitric acid?

Silver nitrate solutions.

What are the three silver halide ions?

Silver chloride, Silver iodide and Silver bromide.

What colour precipitate is silver chloride?

White.

What colour precipitate is silver iodide?

Yellow.

What colour precipitate is silver bromide?

Cream.

Sulfate ion in a solution produces a white precipitate in the presence of dilute hydrochloric acid and what other solution?

Barium chloride solution.

Elements and compounds can be detected using what method?

Instrumental methods.

What are advantages of using an instrumental method?

More accurate, sensitive and rapid.

What is an example of an instrumental method?

Flame emission spectroscopy.

What is done in the flame emission spectroscopy test?

The sample is put into a flame and the light given out is passed through a spectroscope. The output is a line spectrum that can be analysed to identify the metal ions in the solution and measure their concentrations.