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please help me understand the soution to a gchem question from destroyer

Discussion in 'DAT Discussions' started by skim1988, Aug 6, 2011.

  1. skim1988

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    In H2O, which of the following is the weakest base?

    a)HClO4
    b)NH3
    c)NH2-
    d)OH-
    e)ClO4-

    the answer is E but shouldn't the answer be A? I understand that ClO4- is a weak base because its conjugate acid is a strong acid but A is a strong acid therefore the weakest base isn't it? what am i missing here?
     
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  3. FROGGBUSTER

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    I thought the same when I came across this problem. I think it's a mistake.
     
  4. PooyaH

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    HClO4 is not a base! It's a weak acid.
     
  5. yappy

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    Perchloric acid is a strong acid. Therefore, its conjugate base would be a very very very weak base; because in theory it never accepts an H+.

    I think including both the acid and base form is kinda cheap. Base is a function not a classification. To be clear, OH- (a "base") can accept an "H+" or in some conditions donate a proton forming O-- acting as an acid.

    EDIT: now that I think about it... Hclo4 functions as an acid not a base. So might as well go with the conjugate base of the known strong acid. E) CL04-.

     
    #4 yappy, Aug 7, 2011
    Last edited: Aug 7, 2011
  6. PooyaH

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    Jesus, yeah HClO4 is a strong acid. My bad. It's been a long day!
     
  7. PooyaH

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    Yeah, the reason why it can't be HClO4 is because it's not a base at all.
     
  8. LetsGo2DSchool

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    :laugh: You need a brewski.
     
  9. skim1988

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    oh ok got it! thanks a lot guys.
     
  10. PooyaH

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    At this point I need keg.
     

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