Sulphur Trioxide Sulphur Trioxide Preparation of Sulphur Trioxide Sulphur trioxide is prepared by the direct union of gaseous sulphur dioxide with ozone. 2 SO3 Sulphur trioxide is prepared by heating concentrated sulphuric acid with a large excess of phosphorus pentoxide, P2O5. 2 HPO3 Sulphur trioxide is more conveniently on the small scale by distilling fuming sulphuric acid in a retort and collecting the sulphur trioxide in a perfectly dry receiver cooled in a freezing mixture.
Sulphur trioxide reacts vigorously with water to form sulphuric acid.
H2SO4 Sulphur trioxide reacts with water vapour in the air to form white fumes consisting of tiny droplets of sulphuric acid. Sulphur trioxide readily reacts with basic oxides to form sulphates. Sulphur trioxide is a planar covalent molecule with one sulphur oxygen double bond and with a bond angle of 120 degrees between the other two oxygen atoms. Sulphur trioxide has a resonance structure. All Rights Reserved.