Calculate how much H2SO4 will be obtained from 400 gm of Oleum sample having labelling 104.5%?

SOLUTION: 104.5 % labelled means 100 Oleum sample required 4.5 gm water to completely destroyed free SO3 present in 100 gm sample

100 gm Oleum sample require 4.5 gm water to destroyed all free SO3

Weight of SO₃ in destroyed by 18 gm water is =18/18x80= 80 gm 

Weight of H₂SO₄ = 400-80= 320 gm present in 400 gm Oleum sample

Weight of H₂SO₄ newly formed is =18/18x98= 98 gm

Total Weight H₂SO₄ =320+98=418 gm