Talk:Superacid

Nitric acid
The "strong acid" page ranks nitric acid as being "stronger" than sulfuric acid (without specifying what "stronger" means). If this means that anhydrous nitric acid (if it exists) is stronger than anhydrous sulfuric acid, nitric acid should be noted on this page. If not, should this perhaps be clarified on the "strong acid" page? 63.225.174.209 03:59, 4 July 2006 (UTC)


 * Strong acid isn't a great article, but it does explain that acid strength is measured by the acid dissociation constant. The anhydrides have nothing to do with it. —Keenan Pepper 04:51, 4 July 2006 (UTC)kjgvvjk


 * Yes, acid strength is only determined by the extent of the molecule to be broken apart by the attractions of the poles in water, or whatever it is that the acid was placed in. Which incidently is what allows for the the formation of superacids, the fact that water is not used. Helgers7 06:56, 17 March 2007 (UTC)

Up-Close Working
Has anyone ever had up-close working contact with fluoroantimonic acid, apparently the strongest known super-acid system?
 * Answer -

How quickly did it dissolve different substances that you had placed in it, candle wax for example, metals, etc.?
 * Answer -

What did it look like as they were dissolving?
 * Answer -

I found a page that references a stronger known strongest super acid, a mixture of antimony pentafluoride, fluosulfonic acid, and sulfur trioxide. Reference has a vas Deferens(sp?)

It mentions the Hammett acidity function, and lists various strongest super-acids in a small list:
 * 11.0 for sulfuric acid (H2SO4)
 * 12.6 for fluosulfonic acid (HSO3F)
 * 15.2 for fluoantimonic acid (2 HF + SbF5 -- probably H2F(+)SbF6(-) )
 * more than 16 for fluosulfonic acid plus sulfur trioxide plus antimony

pentafluoride.

The text it references for this mixture is Greenwood & Earnshaw, Chemistry of the Elements, pages 57 and 664, 1989 edition.

Is there any truth to this book reference? Comments? Observations? Other things you want to mention?
 * Answer - The Hammett acidity function of fluoroantimonic acid is supposed to be -31, so it is probably stronger than the superacid you mentioned. The page does say that the strongest superacids are combinations of a very strong Lewis acid and a very strong Bronsted acid. Supposedly SbF5 is the strongest Lewis acid known, so adding different super-Bronsted acids will result in very strong superacids. Noting that adding SO3 to H2SO4 increases its strength substantially, the same effect would apply to fluorosulfonic acid. So that solution would probably be the second strongest superacid solution known (unless HF in some Lewis acid other than SbF5 is stronger). Bbi5291 21:23, 31 July 2007 (UTC)

—The preceding unsigned comment was added by TAz69x (talk • contribs).

Incorrect Information
"Fluoroantimonic acid is 2×1019 times stronger than 100% sulfuric acid."

The page for fluroantimonic acid lists it as only 2000 times stronger. Which is correct? —The preceding unsigned comment was added by Icedemon (talk • contribs).

But the page for fluroantimonic acid says it is 2 times 10 to the 19 times stronger, and this page says it is only 10 to the 16 times stronger. They conflict! Mathwhiz90601 02:55, 4 February 2007 (UTC)

The figure SHOULD be 2*10^19 times stronger than 100% sulfuric acid. —The preceding unsigned comment was added by 65.173.91.49 (talk • contribs).


 * Both of you really need to read WP:V and WP:CITE. —Keenan Pepper 02:03, 17 October 2006 (UTC)


 * You really need to learn to criticize less harshly, and probably in a private message. Icedemon 01:47, 24 October 2006 (UTC)

I recommend you read the acid dissociation constant page, and understand what pKa means. From there, pKa of fluoroantimonic acid is -25.00, while the first ionization constant of sulfuric acid is -3.00. So the concentration of protons is roughly 10^(-3-(-25))=10^22 moles higher per liter in fluoroantimonic acid than in sulfuric acid. HA -> H+ + A-, Ka=[H+]*[A-]/[HA] = [H+]^2 / ([HA]initial-[H+]) because [A-]=[H+], and [HA]final=[HA]-initial minus the dissociated moles. It's quadratic equation (ax^2+bx+c=0) in [H+], have to solve it for actual numbers. I'm at the library now. Bracket means concentration in moles per liter of what's between the brackets, i.e. [H+] is moles of proton per liter, [A-] is moles of anion/counterion per liter, [HA] means equilibrium concentration of undissociated, nonionized acid per liter. Sillybilly 23:46, 5 February 2007 (UTC)


 * I'm so stupid. Most basic of basic chemistry mixup. The pKa has nothing to do with the proton concentration, it's not directly related, other than through the pKa equation. So 10^22 or 10^25 has nothing to do with the concentration of protons, you cannot substract pKa or pK values like that, especially when the equilibrium formula has exponents such as cubes, which end up with pk constants of 10^300 or so, even though the actual equilibrium concentrations are on the order of 10^-6. I don't know what possessed me, I must have remembered looking at pH tables of acid and seeing pH of -25 or so, instead of pKa of -25 or so. With pH the values are directly related to concentration, to proton concentration, pH=-log [H+], that's where the confusion was. Is this a good excuse? I woke up the next morning feeling so stupid. Sillybilly 22:10, 7 February 2007 (UTC)

100% sulfuric acid
I had the notion (from my Dad and his chemistry books, both of which are from quite some time ago) that anhydrous hydrogen sulfate is not considered an acid at all; it's supposed to need at least a little bit of water to enable dissociation. I thought that's precisely why the books refer to it as "hydrogen sulfate" rather than "sulfuric acid".

If that's correct, then the comparisons with "100% sulfuric acid" need some sort of explanation. If it's incorrect, could someone explain to me in what way it's incorrect? --Trovatore 22:45, 14 May 2007 (UTC)
 * Read the article sulfuric acid. Sulfuric acid has actually better autodissociation than water. --Vuo 11:49, 3 August 2007 (UTC)

Unbalanced equation
The last equation is not balanced correctly. There are too many hydrogen atoms on the reactants side. This is making question how the acid really works. Is it the number of hydrogen atoms thats incorrect or is it the incorrect organic isomer. I drew ever isomer for that can arise from reacting a methyl cation with three moles of methane and they all get that same molecular formula so it must be the wrong number of hydrogen product. —Preceding unsigned comment added by 216.159.75.118 (talk) 09:42, 2 December 2007 (UTC)

Are you sure it is unbalanced? Dogposter (talk) 22:04, 27 July 2009 (UTC)


 * Maybe not balanced back in 2007 but certainly balanced in 2009 V8rik (talk) 20:06, 28 July 2009 (UTC)

Naked protons?
No. See. Protons hop from anion to anion in superacids via the Grotthuss mechanism, just as they do in water. This accounts for ionic conductance in liquid fluoroantimonic acid, without having to postulate H+ ions of the sort one finds in hydrogen plasmas. S B Harris 00:46, 27 February 2011 (UTC)

difference between strong acids and superacids
The question about nitric acid in the first section on this talk page was only partially answered although the strong acid article's incorrect claim of nitric acid being stronger than sulfuric acid has been corrected.

But neither that nor this article explain what the difference is between strong acids and superacids, and that article confusingly puts hydrochloric and other acids in the list of strong acids that are superacids according to the definition given in both articles. What a mess.

And if they are apples and oranges, that should be explained. In any case, this article on superacids should also mention that hydroiodic, hydrobromic, perchloric, and hydrochloric acids are superacids and not only talk about the most powerful ones.

--Espoo (talk) 21:03, 4 December 2014 (UTC)

Wiki Education assignment: 4A Wikipedia Assignment
— Assignment last updated by Kmijares (talk) 22:40, 15 November 2023 (UTC)