Sulphurdioxide – SO2
Also called Sulphur (IV) oxide, sulphurous anhydride or sulphurous anhydride, Sulphur dioxide is an acid gas.
This improvement resulted in part from flue gas desulphurisation, a technology that enables SO2 to be chemically bound in power plants burning sulphur-containing coal or oil. In particular, calcium oxide (lime) reacts with sulphur dioxide to form calcium sulphite:
CaO + SO2 ? CaSO3
| Properties | ||
| Molecular formula Molar mass Exact mass Appearance Density Melting point Boiling point Solubility in water Vapour pressure Acidity (pKa) Basicity (pKb) Viscosity | SO2 64.066 g mol-1 63.961899934 g mol-1 Coloress gas 1.25 g cm-3 -72 °C, 201K, -98 °F -10 °C, 263 K, 14 °F 94 g dm-3 237.2 kPa 1.81 12.19 0.403 cP (at 0 °C) | |
Where it comes from
SO2 is released by volcanoes and various industrial processes. Since coal and petroleum often contain sulphur compounds, their combustion generates sulphur dioxide, unless the sulphur compounds are removed before burning the fuel. Sulphur oxides from industrial sources are emitted in the atmosphere through the installation of combustion fed by sulphurous fuels and other activities in the manufacturing sector. SO2 is also contained in waste.
Impact on people and the environment
This gas is toxic, irritating, non flammable and non explosive. It has a pungent odour. Inhalation of this pollutant is also toxic and an irritant of the respiratory system. Exposure to this product is corrosive for the skin and eyes. Sulphur dioxide is a major air pollutant and has significant impacts upon human health. In addition the concentration of sulphur dioxide in the atmosphere can influence the habitat suitability for plant communities as well as animal life. Sulphur dioxide emissions are a precursor for acid rain and atmospheric particulates.