I am trying to find a pKb value for potassium carbonate, I have looked all over the “entar web”, and I cannot find a dissociation constant table of more than 15-30 entries. I must be doing it all wrong™.

Can someone point me to an online resource that will give me acid and base dissociation constants for, like, everything?

Thanks for the response, let me clarify and ask a question:

Mainly I was looking for a comprehensive database of dissociation constants, if anybody knows one.

Your answer suggests that knowing the pKa of carbonic acid is sufficient… does that imply that the basicity of potassium carbonate is the same as sodium carbonate is the same as calcium carbonate?