Dramatic depictions of acid dissolving bodies are widespread in cinema, but the true identities of the caustic fluids are usually left rather vague, begging the question: are they real? There are certainly acids that can dissolve flesh (watch some make quick work of a chicken leg here), but beyond normal acids, exists an elite group of burny-bad-time liquid: the superacids.
Superacids – like fluoroantimonic acid, the strongest acid in the world – are acids that are stronger than 100 percent sulfuric acid. They’re usually made by combining two strong acids, one of which contains the hyper reactive element fluorine, resulting in an exceedingly acidic compound that just loves to give away protons.
What is fluoroantimonic acid?
Fluoroantimonic acid, The Boss of superacids, is a blend of hydrogen fluoride (HF) and antimony pentafluoride.
The superacid known as “magic acid” (made of fluorosulfuric acid and antimony pentafluoride) is 100 billion times the strength of 100 percent sulfuric acid, reports The Royal Society of Chemistry, very much earning the title of “superacid”.
How strong is fluoroantimonic acid? Well, it’s 100,000 times stronger than magic acid, or 10 quadrillion times stronger than pure sulfuric acid. In case keeping on top of all those zeroes is proving difficult, perhaps this video of some chicken being doused in fluoroantimonic acid will help to put all the stats into context.
Is fluoroantimonic acid capable of dissolving anything?
Interestingly, acid strength (which is defined by an acid’s ability to donate protons to other molecules) isn’t always a clear cut measure of corrosiveness. Magic acid was so named after a candle was dipped into it which quickly dissolved, something that was thought to be impossible because candle wax’s hydrocarbons are such stable compounds.
Fluoroantimonic acid, on the other hand, which can transfer protons to methane, does little damage to a birthday candle as seen in this video from Chemical Force. However, with a Hammett acidity function of -28 it’s still pretty intimidatingly corrosive, even able to eat through glass, which is why it has to be stored in the synthetic fluoropolymer Polytetrafluoroethylene (PTFE), also known as Teflon.
While it might not look like much, Teflon contains some of the toughest bonds in organic chemistry (C-F bonds) making it a worthy keeper of fluoroantimonic acid. If that bath tub scene in Breaking Bad taught us anything, it's that things can get very messy when you don't respect an acid's storage suggestion.
What is fluoroantimonic acid used for?
The extreme nature of fluoroantimonic acid makes it a valuable tool in chemical engineering and organic chemistry. Its penchant for giving out protons like Oprah enables it to remove compounds bound to tricky solvents, reports ThoughtCo., such as methane from neopentane.