Testing ions

- A flame test is where the substance is put under a bunsen burner, and the colour of the flame tell us of ions present.

Lithium (Li+) : Crimson red flame

Sodium (Na+): Yellow/ Orange flame

Potassium (K+): Lilac

Calcium (Ca2+): Brick red

Barium (Ba2+): Green

- You need to remember all of these

- When sodium hydroxide is added, these ions form a different coloured precipitate.

Aluminium: White precipitate

Calcium: White precipitate

Magnesium: White precipitate

Copper (II): Light blue precipitate

Iron (II): Green precipitate

Iron (III): Red precipitate

Testing for a carbonate:

Add a WEAK ACID --> Salt, Water, Carbon Dioxide is formed

Testing for sulfates:

Add HYDROCHLORIC ACID --> White precipitate formed

Testing for nitrates:

Add SODIUM HYDROXIDE, then ALUMINIUM --> Ammonia given off

Testing for halides:

Add NITRIC ACID and SILVER NITRATE:

Chloride ions: White precipitate formed

Bromide ions: Cream precipitate formed

Iodide ions: Yellow precipitate formed