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What is the ionized and unionized form?

  1. Aug 25, 2012 #1
    So I'm doing a henderson hasselbach type problem.


    I learned in biochemistry that the uncharged form is the conjugate base [A-] and the charged form is the acid [HA]. However, I looked up on google about the henderson hasselbach equation and found that the unionized form is [HA], while the ionized form is [A-]. I got it from this: http://www2.umt.edu/medchem/teaching/Lecture1-Pharmaceutics.pdf [Broken]


    Does uncharged and unionized mean the same thing? I thought it did, but now I'm a bit confused.
     
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Aug 25, 2012 #2
    Ions are atoms/molecules where the total number of electrons does not equal the total number of protons. If you have more electrons than protons, one has an anion - a negatively charged ion. If you have more protons than electrons, one has a cation - a positively charged ion. And then you can also have zwitterions.

    Remember, amino acids can be zwitterions. They have both a carboxylic acid functional group and an amine functional group. The protonation state for the two groups will vary as a function of pH. This, it seems, is the source of the confusion, based on what you've written.
     
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