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Homework Help: Organic chemistry butene

  1. Aug 29, 2012 #1
    1. The problem statement, all variables and given/known data
    But-2-ene reacts with bromine in the presence of concentrated aqueous sodium nitrate to give the following compound

    Which of the following statement is correct.
    a.the electrophile is NO2+
    b.Only 2,3-dibromobutane is formed.
    c.Resultant solution shows optical activity.
    d.Mechanism involves an initial electrophilic attack followed by nucleophilic attack
    2. Relevant equations

    3. The attempt at a solution
    I know that B is out cause you can have -Br and -OH instead of just 2-Br.
    C is also out because the compound can be attacked from both side(Trigonal planar)
    A or D is correct.D makes sense to me but isnt NO2+ a electrophile. In this case i would presume NO2+ is somehow formed which attacks OH group....If not what is the case???
  2. jcsd
  3. Aug 30, 2012 #2


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    See, the halide molecule also polarize and form halide electrophile, in this case, Br+ can form. NaNO3 cannot give NO2+ ion, as it is obtained by "protonation" of nitric acid, which is not a simple task, considering nitric acid itself is very strong acid. That's what I feel.
  4. Aug 30, 2012 #3


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    Name these ions... NO3- and NO2+

    Which one is present in your proposed mixture?
  5. Aug 30, 2012 #4


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    Care to elaborate, as chemisttree asked?

    UPDATE: I have formed on paper the compound H3C-CH(ONO2)-CHBr-CH3, considering Nitrate group, albeit I am afraid I may have have bent some rules (which looks like the case, forming acid out of aqueous nitrate ions) And I have reached to following answers: C, D.
    Last edited: Aug 30, 2012
  6. Sep 3, 2012 #5
    The answer was given to be D only.
    The carbon is directly bonded to oxygen,and the oxygen directly bonded to NO2.So it seems to be O- and NO2+???And i presume the O- to be created from a alcohol group and the H+ is removed....
    Answer is not C as the compound is trigonal planar and can be attacked from both sides,hence a racemic mixture..
    But i don't understand how C(O)(NO2) is formed as it seems impossible to form NO2+ from this reaction....
  7. Sep 3, 2012 #6


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    Esterification I guess.
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