Have chemists created extremely powerful acids that are next to impossible to contain? What is the strongest acid currently discovered?
The strongest acids are HClO[sub]4[/sub], HCl, HBr, HI, HNO[sub]3[/sub] and H[sub]2[/sub]SO[sub]4[/sub]. HF can dissolve glass, so it gets stored in plastic bottles.
No universal solvent has yet been discovered.
nitrohydrochloric acid (a mixture of nitric and hydrochloric acids; commonly called aqua regia) is the only acid that can dissolve platinum, so I’d say that’s a pretty strong acid.
First of all, how are we defining “powerful”? By pH? By ability to dissolve X, Y, and Z? Something else entirely? Insider, what did you have in mind?
On a related note, is a universal solvent possible? My first guess is that it’s probably not, but I’m pretty good at being wrong.
But it can still be stored in glass containers. I’d appreciate it if a chemist could explain to me what it is, physically, that makes some acids dissolve glass but not gold and aqua regia dissolve gold but not glass.
The strength of an acid is the ease at which it donates protons (protons are the H+ bit in the acid). Strong acids are difficult to differentiate in terms of acidity, in water. The water levels out the strengths of each. In an acidic solution the strong acids can be differentiated from one an other. So in a nutshell - it depends on the environment the acid to determine its relative strength.
Priceguy - HF is effective at dissolving glass because the F- has a high affinity for Si, which is in glass. The F-Si bond energy is very high, greater than any of the other halides, such that HF reacts with SiO2 vigorously at room temp. The atoms in the acid and the glass want to form the most stable bonds in the products - that is what pushes the reaction towards the products.
Note: glass is also attacked by hot OH-. Si-OH is also a strong bond (a product).
Also, F- is a small highly electronegative anion.
I would have thought that HF would attack Pt metal, since Pt halides are stable.
Not sure of the mechanism of aqua regia on platinum and gold. Reaction, i think is:
Au + 4HCl + HNO2 --> HAuCl4 + NO + 2H2O
Gold halides are stable, and I know that Au only dissolves in HCl if a strong oxidising agent is present (ie HNO3).Presumably H2O2 would also do the trick. I suppose the oxidising agent must be needed to obtain the +3 oxidation state to form the stable AuCl4-.
So, it all depends on affinity of the anion for the substance to be dissolved. SiC (Silicon Carbide) is resistant to HF, but not H3PO4. CN- also dissolves Au and Pt in an oxidising environment to form the cyano complex.
Bravo, Antechinus.
I second Desmostylus.
Probably the closest thing to a universal solvent is good old H[sub]2[/sub]O. Water can actually dissolve a lot more different substances than most acids or organic solvents.
Check out Getting the Jump on Superacids, which mentions some (fairly) newly-discovered types that are even stronger.
I’m sorry, it’s now late at night. But most of that acticle makes no sense to me.
Despite their industrial applications, superacids aren’t well understood, in large part because they are what they are — extremely strong acids.
So super acids aren’t well understood because they’re super acids.
“They are very toxic, very volatile,” says Klein’s collaborator, post-doctoral fellow Dongsup Kim, “and it’s difficult to do experiments.”
So they are are poisonous and evaporate readily.
At this point the BS meter overloads.
On a side note, D-Lysergic acid is so strong it can dissolve reality.
Desmostylus
At this point the BS meter overloads.
OK, the article’s not so great (it was late when I posted). Here’s another cite, slightly less gee-whiz. But they are real: compounds that vastly exceed ordinary acids in the ability to donate protons these enabling them to act on normally inert substances such as hydrocarbons. The 1994 Nobel Prize for Chemistry was awarded for work with superacids.
The strongest acid I believe is aqua regis, a mixture of concentrated niteric and hydrochloric acids. As an acid, HF isn’t very strong.
Thanks for the cite, raygirvan. 
aqua regis
I thought that was an English spa town.
This gets asked all the time, and the answer is–of course–it depends on what you mean, although superacids seem to take the cake for generally being nasty.
For example, HCl is stronger than HF, but I’d much rather get it on me. TFAA burns people like all hell (I speak from experience) because it’s organic, and quickly seeps through the oils in your skin, and trying to wash it off won’t do you much good. Glacial Acetic Acid is fairly weak, but get some on you, and within a day or two your skin will harden and crack off rather painfully–worse damage than a short exposure to many much stronger acids.
(I used to keep a saturated bicarbonate solution in a beaker on my bench for plunging my hand into after spilling acid all over myself. I used it frequently)