Aluminium
The Blast Furnace
Purification of Copper
Crude Oil
Electrolysis
Analysing Gases
Haber Process
Solubility of Salts
Steel
Test for Anions
Test for Cations
Titration

Other Section

Carbonate

Ion CO₃^2-, carbonate is found in limestone, or calcium carbonate (CaCO₃).

To test for it, you must first: Add a dilute acid to the sample. A gas is given off which when tested, should prove to be carbon dioxide.

Sulphate and Sulphide

Sulphate is SO₄^2- and
Sulphide is SO₃^2-

Adding barium chloride to the solution you are testing a white precipitate will form. If you add hydrochloric acid, the sulpahte (SO₄^2-) WILL NOT dissolve and the sulphite (SO₃^2-) will.

Halogen Tests

The test for halogens, or halide ions, is to add silver nitrate to a solution. We often add some nitric acid first as well. If there are chloride, bromide or iodide ions in the soltion they will react with silver to form a precipitate. The different precipitates are summarised in the table below.

The ionic equations for these reactions are:

Ag⁺ (aq) + Cl^- (aq) AgCl (s)
Ag⁺ (aq) + Br^- (aq) AgBr (aq)
Ag⁺ (aq) + I^- (aq) AgI (aq)