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Effect of ph on uv absorbance of benzoic acid

  1. Jan 4, 2010 #1
    i was recently reading about uv absorbance, and i understand why species such as the phenoxide ion and aniline absorb uv radiation at longer radiation and with more efficiency than their protonated counterparts.
    i have spent long hours, however, trying to figure out why a benzoate ion might absorb at a shorter wavelength, and with less efficiency, than benzoic acid.
    i have attached the source which suggests that this is true; there is a graph on page 5. my last resort is to say that the source is wrong but i want to make sure... can anyone help?

    Attached Files:

  2. jcsd
  3. Jan 4, 2010 #2


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    How might dimers of benzoic acid be different at high pH vs. low pH?

    http://pubs.acs.org/doi/abs/10.1021/ja00503a016" [Broken]
    Last edited by a moderator: May 4, 2017
  4. Jan 7, 2010 #3
    of course!!

    ...much appreciated, thank you.
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