Question

during the reaction of "benzoic acid" with "ethanol" (esterification) -----> dry HCl is used and not conc. sulphuric acid to avoid sulphonation of the ring.........During oxidation of "bezaldehyde" "potassium permanganate" and conc. sulphuric acid are used... so WHY is conc. Sulphuric acid used, can't sulphonation happen to the benzene ring of "bezaldehyde" ??????