Cations and Anions

1) Make sure the wire loop is clean by dipping it into hydrochloric acid

2) Rinse with distilled water

3) Dip the wire loop into a sample of the compound

4)Put the wire loop into the blue bit of the bunsen flame, this is the hottest part

5)See what colour the flame goes

Lithium - crimson flame

Sodium- yellow flame

Potassium- lilac flame

Calcium- red flame

Barium- green flame

1) Place your compound on a plate

2) Add a few drops of Sodium Hydroxide to the solution

3) If a coloured precipitate forms then you can identify the metal that was in the solution

Calcium - white

Copper- blue

Iron (II)- green

Iron(III)- brown

Aluminium- white,  but it redissolves in excess NaOH to form a colourless solution

Magnesium- white

1) React the carbonate soultion with a dilute acid

2) It  will form carbon dioxide as a by-porduct because:

Acid + Carbonate ----------> Salt + Water+ Carbon Dioxide

3) If the compound is a carbonate then carbon dioxide will be produced which can be bubbled through lime water.

4) The lime water will go cloudy if carbon dioxide is present

To test for Chloride, bromide or iodide ions:

1) Add dilute nitric acid to the solution

2) Add silver nitrate solution

3) If a halide ion is present then a precipitate will form

4) The halide ion can be identified depending on the colour of the precipitate.

Chloride forms a white precipitate

Bromide forms a cream precipitate

Iodid forms a yellow precipitate

1) Have a solution that contains sulphate ions

2) Add dilute hydrochloric acid

3) Then add barium chloride solution

4) A white precipitate will form. This is barium sulphate and it means that the original solution contained sulphate ions.