Question

Give reasons for the ${SO}_4$ is easily hydrolysed whereas ${SO}_2$ is not easily hydrolysed.

Answer 1

sulphate ion is very weak base while $HS{O}_4^{-}$ is a fairly strong acid with $K_a=0.01$. On the other hand , $H_{2}S{O}_4$ is very strong acid. because it is such a weak base, sulphate ion undergoes negligible hydrolysis is aqueous solution. But $S{O}_2$ easily hydrolysed , sulphuric acid exhibits a dramatic catalytic effect on the hydrolysis reaction of $S{O}_2$ as it lowers the energy barrier by over 20Kcal/mol.