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most acidic

Discussion in 'DAT Discussions' started by sciencegod, Dec 29, 2008.

  1. sciencegod

    sciencegod Super Member
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    guys what's more acidic phenol or c6h5NH3+ with a no2 attached to para posiiton.
     
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  3. Sublimation

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    Draw them both out. And the one with the most resonance structures possible is the more acidic one :)
     
  4. sciencegod

    sciencegod Super Member
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    the nh3+ on ring has no resoannce structures yet kaplan says its mpre acidic.
     
  5. montag925

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    by rule of thumb, and for the simplicity of any question asked on the DAT:
    the more electron withdrawing a group on a benzene ring is, the more acidic it will be...on the contrary, the more electron donating, the more basic.
    to break it down even down farther, H+ groups (such as those in NH3) are elctron withdrawing, as compared to -OH which is electron withdrawing, but not to the same extent.
     
  6. joonkimdds

    joonkimdds Senior Member
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    shouldn't answer be phenol since NO2 from the other one is electron donating and that's counteracting against electron withdrawing to make it less acidic?

    By the way, how do we know which electron withdrawing is more electron withdrawing (more acidic) than the other?
    do we have to memorize strongly, moderately, weakly activating/deactivating or is there an easy way to understand the concept:?
     
  7. sciencegod

    sciencegod Super Member
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    don't think your right. electron donating and withdrawing have nothing ti do with the acidit.y all it could do is if its a secong substituent on a ring it would stabilize the anion but not if its the only substituemt. that would have nothing to do with acititudy or basicity.
     
  8. nhpham2

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  9. sciencegod

    sciencegod Super Member
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    you people seem to not be understanding something. when an acidic gorup has also a withdrawing group on the benzene it makes it more acidic. understood. myh question was in terms of the acidic group itself. that has nothing at all to do with whethere it is electron donating or withdrawing imo.

    doesnt anyone understand what im saying.:eek:
     
  10. nhpham2

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    c6h5NH3+ would be more acidic. And c6h5NH3+ actually has 3 resonance structure if you push the carbocation onto the benzene ring.

     
  11. sciencegod

    sciencegod Super Member
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    there's no carbocation . were talking about what is most stable after it loses the H. (if it were very stable in its current form with + it would not be acidic at all bec wouldn lose H).
     
  12. nhpham2

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    Well judging by pka alone. The anilinium would still be more acidic with a pka of 4.6 and the phenol is at 10. The NO2 group would just make it more acidic.

     
  13. joonkimdds

    joonkimdds Senior Member
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    if e- withdrawing is what makes the ring more acidic, and e- donating does the oppsite, shouldn't phenol be more acidic since the other one has e- donating but phenol doesn';t have.
     
  14. gentile1225

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    any electron withdrawing group on the ring increases the acidity as already stated above. no2 is very deactivating and highly electron withdrawing. also, whenever you have a meta director in the o,p position you highly increase the acidity. draw out the resonance forms.

    hope this helps.
     

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