In the column about “Fire and Brimstone”, some member of the Straight Dope Science Advisory Board writes:
Actually, sulfur dioxide forms sulfurous acid when exposed to water (although air generally does contain some water). Sulfur trioxide, which requires some little effort to produce, produces sulfur**ic* acid when it reacts with water (both oxides are “acid anydrides”: both notionally and actually, the acid is formed when one molecule of water is added to the anhydride).
Of course, I’m sure that Cecil himself would have made this error
“Gold cannot always get you good soldiers, but good soldiers can always get you gold”