Valences

In the column about "Fire and Brimstone", some member of the Straight Dope Science Advisory Board writes:

When ignited (a blue flame), [sulfur] gives off sulphur dioxide (a colorless gas), which forms sulfuric acid when exposed to air.

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[b]ic[/i] 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

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"Gold cannot always get you good soldiers, but good soldiers can always get you gold"

Hmmm. Well, I fell asleep during most of my chemistry classes, but I took my reference from the Encyclopedia Britannica: "Atmospheric oxidation may affect sulphur itself, producing suphuric acid."

It is, I confess, an old Britannica (1951) which I continue to use on the grounds that it is well-written, even if it's facts are sometimes out of date.

That's not too surprising for Brittanica, especially a Brittanica that's not from 1911.

I've read history texts which claim that hydrogen bombs, but not atomic bombs, produce mushroom clouds, and that the term "front" as used in meteorology refers to boundaries between masses of high and low air pressure rather than high and low temperature. (Both assertions are incorrect.)

Since encyclopediae tend to concern themselves more with geography, potltics, and history than with hard sciences, it's not at all surprising that Brittanica would make such a blunder. I'll bet the encyclopedia entry on sulfur has more information about national sulfur manufacturing quotas that it does about sulfur's actual properties.