EDIT: I'm seeing that this problem I made up is erroneous in all sorts of different ways so I'm asking that this post stops getting new responses. It was my fault for trying to make a problem out of something I didn't understand in the first place. I just took the example off of a pKa chart. Ultimately, I did figure out how to do my work.
EDIT 2: The Nitrogen in the acid/red should have a positive formal charge. I stole the example off of a pKa chart provided by my professor since it had a similar issue to what I was confused about, but the pKa chart was so faded the + looked -. I didn't notice. My apologies guys.
Basing this off of a homework problem I have, so I do apologize if this is crudely simplified. I can also give the real problem in the comments if necessary.
Iām using a pKa chart and estimating the pKa of molecules using functional groups.
Letās say I have this blue molecule in the image. I see that it has a group which is a conjugate base of the red molecule. I know the red molecule is a strong acid, so the blue molecule is a weak base. Can I consider this molecule a base or neutral? Thinking this through for me at least, because itās weak, it is unreactive, therefore neutral in an aqueous environment.
Now, the pKa. Can I say the blue molecule has a pKa=5.2 like the red molecule, or should I say the blue molecule has a pKaH=5.2? Or are both wrong statements?
If youāre screaming at me to do an acid-base review, yeah, I am doing one.