[dmajor27]

Based on experimentally determined data, I'm supposed to identify whether the organic acid is mono-, di-, or triprotic.  Then, based on the pKa(s) and molecular weight, determine which specific acid it is.

I know, based on feedback from my professor, that it is diprotic and that all my data is correct.  However, I can't find an acid that better fits my data.

My data is:  pKa1 = 3.36 and pKa2 = 11.81 with a molecular weight of 132.5 g/mol
I chose salicylic acid.
Which, according to the table in the assigned textbook, has a pKa1 of 2.972 and pKa2 of 13.7 with a molecular weight of 138.12 g/mol.


I've flipped through this table countless times now, and I still can't find a better candidate acid.  Apparently, however, there is an acid that fits better both in terms of pKas and molecular weight - based on my professors comments.  So, I don't know if she is basing it off a different table - or if I'm just blind.

[Borek]

Hard to say anything not seeing the table...

[dmajor27]

Well, the table is in my textbook - - I just assumed some here would look up an acid dissociation table online or in some textbook they already owned . . . I'm not asking for it to match up exactly with my textbook, really.  Mainly just looking for suggestions, that way I could look it up in the table I have and see if it was simply an acid I had overlooked.

[matw2]

I don't have a table of PKa values, but you should look up Glutaric acid, it is diprotic with a mass of 135.1.