Oleum is considered as a solution of SO3 in H₂SO4, which is

Last updated: 7/9/2022

Oleum is considered as a solution of SO3 in H₂SO4, which is obtained by passing SO, in solution of H₂SO4 When 100 g sample of oleum is diluted with desired weight of H₂O then the total mass of H₂SO4 obtained after dilution is known as % labelling in oleum. For example, a oleum bottle labelled as 109% H₂SO4 means the 109 g total mass of pure H₂SO4 will be formed when 100 g of oleum is diluted by 9 g of H₂O which combines with all the free SO3 present in oleum to form H₂SO4 as SO3 + H₂O → H₂SO4 What is the % of free SO3 in an oleum that is labelled as '104.5% H₂SO4' ?