Talk:Piranha solution

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isn't "Peroxymonosulfuric acid" the same thing?

I don't think so, primarily for this reason (thanks to rw): piranha solution ages and becomes less effective over time, presumably due to the formation of peroxymonosulfuric acid. I'll try to add a bit about that later (but anyone else? feel free!) --Terry Bollinger 03:39, 27 July 2006 (UTC)

It is chemically identical. H2SO5 is the product in both reactions. Caro's acid, piranha solution, or peroxymonosulfuric acid decomposes rapidly and is therefore only produced in situ and immediately prior to use.SuperFluid 21:49, 6 July 2007 (UTC)

"One must always add the peroxide to the acid, not the other way around."
Shouldn't that be the other way around? i.e. First rule of chemistry class is NEVER mix anything into an acid.

I agree with the poster above. I often use piranha solution to clean glassware and I always pour the sulfuric acid onto the hydrogen peroxide solution. The idea being that because sulfuric acid has a sizeable enthalpy of mixing, i.e. it heats up when diluted. So when you add something, your small amount of water heats up and will boil and splash and if you do it the other way round you have more water to absorb the heat so you will diminish splashing. Another useful thing to know is to use a big enough beaker, at least twice the volume of the piranha solution you want to make. 134.58.253.113 15:56, 15 February 2007 (UTC)

I have mixed it using both methods and have never experienced any sort of problems with boiling over or splashing, as long as the addition is done slowly and at RT. For simplicity, I instruct people to follow the "AAA" rule--always add acid (when diluting acids). This is simply for consistency and so that you do not initially make a very concentrated solution of acid by adding a small amount of diluent.SuperFluid 21:58, 6 July 2007 (UTC)

I believe the "Chemistry" section needs attention. To my knowledge, the equation is wrong and should be written to reflect the formation of H2SO5, not elemental oxygen. The NASA reference to atomic oxygen does not have bearing in aqueous chemistry. Strong acids (and bases) are known to clean organic residues from glass and other surfaces. H2SO5 is a very strong acid. There is no reference (that I have seen) for the formation of atomic oxygen in aqueous solution.SuperFluid 22:20, 6 July 2007 (UTC)

The chemistry does look bizarre and the NASA reference is irrelevant (removed). Expert tag added. 84.92.241.186 20:08, 19 October 2007 (UTC)