HF is an extremely nasty acid, don't let the MythBuster's episode fool you into thinking you won't regret a splash of HF (believe me, I've experienced one). One of the real dangers of HF can be described using the principles that Adam taught.
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| A very happy moment for anyone interested in chemical education |
That explanation by Adam was probably the best chemistry related scenes I've seen on television in a long time. It's great to see chemistry on national television in a positive light. Adam's explanation was both accurate and entertaining and I loved it.
That being said, I think they missed out by not explaining the reason that HF is so dangerous. This may sound counter-intuitive, but it's precisely because it is a weak acid that HF can kill you without warning. As Adam said, HF doesn't release a lot of hydrogen atoms. This means that you can be "burned" by HF without even realizing it. There is a small amount of fluorine released which can bind to calcium in your blood and bones. This releases even more fluorine (Le Chatelier's principle) which binds to more calcium in your bones and blood. Even small HF splashes can lead to death by robbing your body of necessary calcium. HF can lead to a host of health problems, so please don't assume that part of the myth is busted.
I wish the MythBusters would have been more thorough with their HF testing. They were quite thorough testing their "special sauce", but we only got to see 100 mL added to a small sample of meat, steel, linoleum, wood, ceramic, and drywall. Here's the thing: HF is known to etch glass. That's the entire premise for the Breaking Bad episode. The MythBusters test fiberglass later in the episode, why not earlier with the HF? I would have loved to see a full scale HF test, and I think the MythBusters missed the mark by not doing it. It may have taken some extra time to work, but I'm certain a pig, lots of HF, and a fiberglass tub would have gotten closer to a Breaking Bad scene recreation. Sure the pig wouldn't be completely dissolved, but neither was the body.
Instead of a full scale HF test the MythBusters decided to change the acid they were using. Now, the MythBusters wisely chose not to divulge what they used to actually dissolve a body. That's not really the sort of education they're interested in giving, I assume. They did give a few hints about the acid they were using and it should have been clear to most chemists that the nasty "special sauce" they used would indeed eat through a pig like a tub full of piranhas - which it did. I thought the full scale test of their "special sauce" was great. They failed to make one connection, though. The myth of easily dissolving a body in acid is busted because that process is extremely exothermic. Just look at the steam rising from this acid bath.
The mercury fulminate scene was the other myth they tested, and it didn't fare well at all. The myth was easily busted, which is a result I would have expected given the extreme nature of the myth. To defend my favorite show, though, the science was exaggerated as a plot device. As I said in our most recent podcast with See Arr Oh, I think exaggerated science is fine as long as it's necessary for the plot and not too unbelievable.
In the end I give this episode of MythBusters an A-. The only thing I think it as missing was a better treatment of what HF can actually do. They did an excellent job of explaining acid chemistry, which was nice.