Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook