How would we represent the reaction of #SO_2# with #K_2Cr_2O_7# to give #SO_3#?
We would assume that the sulfur dioxide is oxidized to sulfur trioxide.
And dichromate is reduced to chromic ion......:
And we take
Are charge and mass balanced? If the answer is no then we cannot accept the reaction. Industrially, the oxidant is oxygen gas. I do not know if the reaction would proceed as written.