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simple question about acidity

Discussion in 'MCAT: Medical College Admissions Test' started by 134317, Mar 6, 2007.

  1. 134317

    134317 Guest

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    What's more acidic? An ether, or an aldehyde?

    e.g. CH3-O-CH3 vs. CH3CHO


    Thanks!
     
  2. QofQuimica

    QofQuimica Seriously, dude, I think you're overreacting....
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    The aldehyde is more acidic. And the acidic proton is NOT the aldehyde one (i.e., the one attached directly to the carbonyl). It's the methyl group protons that are acidic.
     
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  3. OP
    OP
    134317

    134317 Guest

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    Sweet. Makes sense. Thanks a lot.
     
  4. Critical Mass

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    :thumbup: It has to do with the electron pull away from the methyl by the carbonyl/aldehyde or something like that. It leaves one of the methyl protons feeling less welcome.
     
  5. al3ck

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    Keto enol for?
     
  6. gujuDoc

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    Q,

    Just a curious question, but the acidity of an ether and aldehyde and other organic groups can also be explained in terms of their electron withdrawing and electron donating capacities right???
     
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  7. HelpingHand

    HelpingHand Where's my white coat?
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    Ethers are not very acidic at all. Remember that acids are supposed to be good at donating protons.

    I've always wondered, is there a general acidity spectrum of organic compounds?

    (Most acidic) Carboxlylic acids > Aldehydes > Alcohols > Esters > Ketones > Ethers > Alkanes (Least acidic)

    Something like this?? :confused:
     
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  8. QofQuimica

    QofQuimica Seriously, dude, I think you're overreacting....
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    Yes. A carbonyl is electron withdrawing, while an alkoxy group is donating. So you could explain their relative acidities in terms of whether they stablize or destabilize the conjugate base's negative charge.
     
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  9. QofQuimica

    QofQuimica Seriously, dude, I think you're overreacting....
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    Yes, except that alcohols are usually more acidic than aldehydes, and the acidities of carbonyl compounds overlap with one another. Also, don't forget about alkynes; they're fairly acidic as far as hydrocarbons go. So I would make your list like this:

    (most acidic) carboxylic acids > alcohols > alpha protons of carbonyls (esters, aldehydes, and ketones) > alkynes > ethers > alkanes (least acidic)
     
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  10. Nikki2002

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  11. J ROD

    J ROD Watch my TAN walk!!
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    Don't forget to add in phenol!

    You know you have to put in the aromatic factor too.

    More fun!!
     
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  12. QofQuimica

    QofQuimica Seriously, dude, I think you're overreacting....
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    You did NOT just post in this thread to make faces. I expect more from you. :mad: :p
     
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  13. Nikki2002

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  14. Nikki2002

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    my one o-chem prof was HOT!! omg omg OMG!!!!!!!!!!!!




    hi Q =)
     

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