A near 100% H2SO4 cloud would be a cloud whose droplets have vanishingly little water in them. As your balloon drifts up or down through it, the sheen of moist

A near 100% H2SO4 cloud would be a cloud whose droplets have vanishingly little water in them. As your balloon drifts up or down through it, the sheen of moisture it collects on its surface is maximum strength sulfuric acid. I hope your balloon is not of a material subject to oxidation, because if it is, you will soon discover a place even worse than in that cloud.