Sciencemadness Discussion Board

Formation of Caro's acid from oxone

furan88 - 4-4-2013 at 19:30

Caro's acid: H2SO5

Oxone: 2KHSO5·KHSO4·K2SO4 Would potassium persulfate ionize in solution from this "triple salt"?

KHSO5 + H2SO4 =(?)= KHSO4 + H2SO5

[Edited on 5-4-2013 by furan88]

Metacelsus - 5-4-2013 at 06:45

Yes, some Caro's acid will be formed, just by virtue of the HSO5- existing at very low pH. However, you won't be able to separate it out from the mixture.

Vargouille - 5-4-2013 at 06:55

First off, Caro's acid is H2SO5. The only way to know whether or not Caro's acid would form, rather than simple hydrogen peroxymonosulfate, is based on the Ka value of Caro's acid. I found one source which claims that the "pK2" of Caro's acid is about 9.4, which is quite weakly acidic. I'm not sure if they mean "pKa" or "pKa2", mind you, but if it is the case that the pKa is 9.4, then bisulfate (pKa= 1.99) will protonate it.