Oxidation of Sulphur dioxide into Sulphur trioxide in the absence of a catalyst is a slow process but this oxidation occurs easily in the atmosphere. Explain how does this happen. Give chemical reactions for the conversion of SO2 into SO3.

Uncatalysed reaction of oxidation of sulphur dioxide to sulphur trioxide is very slow. But in the atmosphere the sulphur dioxide is easily being oxidised to sulphur trioxide because the air in the atmosphere contains particulate matter which acts as a catalyst for the oxidation reaction.


2SO2 (g) + O2 (g) 2SO3 (g)


For eg the reaction can also be promoted by the the presence of ozone and hydrogen peroxide the oxidation of sulphur dioxide takes place as according to the given equations:


SO2 (g) + O3 (g) SO3 (g) +O2 (g)


SO2 (g) + H2O2 (L) H2SO4 (aq)


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