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Sn2 rxn

  1. Dec 13, 2009 #1
    1. The problem statement, all variables and given/known data
    Which would be the stronger nucleophile in a polar aprotic solvent?
    a) H2O or H2S
    b) (CH3)3P or (CH3)3N

    2. Relevant equations

    3. The attempt at a solution
    I'm really confused because in my book, it says that in protic solvents, the larger atoms (I-) are stronger nucleophiles than smaller ones (F-). Then it says that it is opposite for when it is an aprotic solvent (e.g. F- is more nucleophilic than I-)
    In this case, the answer to b) is H2S and c) is (CH3)3P, but shouldn't it be the opposite??
  2. jcsd
  3. Dec 13, 2009 #2
    The answers given for the question is correct and the concept given is wrong.consider protic solvent it consists of H+ ions since bonds between similar sized atoms is strong,the bond between smaller atoms will be stronger if F- is in polar protic solvent,it forms HF molecule which will be more stable than other halogen hydrides
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