sulfur dioxide

Sulfur dioxide (SO2) is a gaseous oxide produced by the burning of fuels containing sulfur. Normally in the form of an extremely irritating gas or liquid. Used in many industrial processes, especially the manufacture of sulfuric acid. Major cause of acid rain throughout USA.

Sulphur Dioxide is produced in many industrial processes, and can be incredibly damaging to the environment if released, most commonly when it forms acid rain by dissolving in the water in clouds, forming a weak acid. It can also affect the respiration of humans and mammals, and can lower the overall atmospheric temperature by favouring cloud formation, resulting in the sun's rays being reflected.

Because of its harmful nature, companies which produce volumes of Sulphur Dioxide as a result of industrial processes are expected to control the amount they release into the atmosphere, ideally releasing none at all. It is most commonly removed using the following reaction:

    2SO₂(g) + O₂ --> 2SO₃(g)

This is an exothermic (in the foward direction) reversible reaction, and so is carried out at low temperatures under high pressure, to maximise the yield of SO₃ obtained.