Which acid is stronger?

Discussion in 'General Science' started by boks, Nov 19, 2008.

  1. boks

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    Oct 10, 2008
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    1. The problem statement, all variables and given/known data

    [​IMG]

    2. The attempt at a solution

    Not I or V because here there's no increase in resonance stabilization.
     
  2. jpanhalt

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    Image did not come through on my computer.

    John
     
  3. boks

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  4. bertus

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    Last edited: Nov 20, 2008
  5. studiot

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    Well I make the compounds
    1) cyclohexanol
    2) phenol
    3) 4methylphenol or p-cresol
    4) dichlorophenol
    5) trichlorocyclohexanol

    Items 1 and 5 are cyclic alcohols which are generally less acidic than the 2,3,4 which are phenols. Ionisation is promoted in phenols compared to cyclo-alkanes/alcohols by the availability of resonance structures in phenols, which stabilise the ionised forms.

    Item 5 has three chlorine atoms which stabilise the ionised form, by induction, over the simpler item1

    But the phenols 2,3 and 4 will all be stronger.

    Of the phenols 3 is slightly weaker than 2 because the methyl group supplies electrons to the ring whilst 4 will be stronger because the two chlorines withdraw electrons.

    So 4 (3,4 dichlorophenol) is the strongest acid.

    You will have to look up the pKa values for yourself.

    Talking of resonance, I hope viewers do not confuse chemical resonance with mechanical/electrical resonance as discussed in other threads here. They are very different animals and bear no relation to each other.
     
    Last edited: Nov 20, 2008
  6. jpanhalt

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    "Congratualations. You are the 1,000,000 visitor. Click here to win"

    I don't see any chemistry question there, and I don't want to click through a bunch of advertising to get to one.

    John
     
  7. studiot

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    I captured the original.
     
  8. Wendy

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  9. mabsj2

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    can't see anything
     
  10. gregdevid

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    hi,
    I can't see and read some parts of your post.
     
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