Hello all,
Something I have wondered for a while is why is there such variation in the reported values of the pKas for strong acids? For example, in one of my organic books, it is reported that the pKa of HI in water is -10. In another book, it is reported as -7, and in yet another it is -11. I have found the same thing for HCl and HBr in various books. For a weak acid such as acetic, though, the value listed is nearly always the same to a couple of decimals. So why is there such variation? If I had to guess, I would say because it is a strong acid, the amount that remains in the unionized form is so small that experimental error has a significant effect on the result.
In many cases its not like it would matter, since it is so strong to begin with. Just curious....
Thanks all,
Eric