What is the most corrosive "acid" known?

I was thinking about everyones favorite alien the Xenomorph the other day and their particularly nasty “acid” blood (I put acid in quotes because all we know is that it is corrosive, not necesarily acidic).

Do such increadibly corrosive substances exist? Are their chemicals that, only a few onces, couold eat through several inches of steel in seconds?

What are these materials and how do they work?

I’m no scientist but I’m thinking that stomach acid, with its Ph of 1.5, could do some damage to metal.

Hydrogen fluoride with water is extremely powerful, even attacking glass.
A mixture of nitric acid and sulphuric acid is not ‘bad’ either.

Both of them are far stronger than stomach acid.

You do not want to mess with Hydrofluroic acid (it’s OK, no gruseome pics).

There is no substance that burns through several inches of steel in a few seconds. I believe you need a 1920’s style death ray fo that.

And by the way, Hydrogen fluoride = Hydrofluroic acid …

Nitpick: Aqueous Hydrogen Fluoride = Hydrofluoric Acid

hmmm. strongest acid i think is perchloric:HClO4… but aqua regia is stronger yet… mixture of concentrated hydrochloric and sulfuric…

I believe perchloric acid is the strongest of all.

Dragon I believe the mixture you described (sulphuric and nitric acid) is aqua regia (royal water) and can dissolve gold.

Darn chaotic - you beat me to the punch.

Great minds think alike though huh ??

and chaotic I think we BOTH got the aqua regia mixture wrong.

It is Nitric acid and Hydrochloric acid.


huh. aqua regia is nitric and HCL… more info, with a dissolving gold video

The most acidic material I’ve ever come across is in the Iron Mountain mines near Redding, California. It’s an old copper/zinc/gold/silver/pyrite mine that’s been abandoned for a number of years now, and is on the Superfund cleanup list. Researchers exploring the mine to determine the source of low acidity groundwater discharge found waters with pH levels as low as -3.6.


Quoting from the above web page:

I don’t think Tom and Becky would have lasted long in there.


i noticed that right before you posted :}

Acidic stomach contents are pretty mild compared to things like nitric and hydrofluoric acid. Vomiting up stomach acid just burns a bit, and it takes months or years of chronic exposure to the acids to make an esophagus scarred or pre-cancerous. But if drinking hydroflouric acid doesn’t kill you on the way down, vomiting it back up pretty much ensures it will finish the job.

I had a feeling you did notice it - but at least I “beat you to the punch” on that one.

So that is it? There is no “concentrated molecular acid” that can eat through several decks of a starship in less than a minute?

Earlier threads:

Acid Test

So - what’s the strongest acid?

It’s not a liquid at room temperature so it’s probably not an “acid” in the sense we’re discussing, but pure gaseous fluorine is probably the most aggressive corrosant in existence. It will attack anything except noble gases and substances that are already completely fluoridated.

It would depend what you meant by ‘strongest acid’ or ’ corrosive’ as some acids are actually quite mild unless you concentrate them.

There is something called ‘Magic acid’, FHSO3-SbF5, aka ‘superacid’ which ranks pretty high.

Dammit, ** Handy!!** beat me to the punch.

Also, can something actually have a negative pH? wouldn’t the lowest they go (for monobasic acids, at least) be a pH of 0 (i.e. fully dissociated)?