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Homework Help: Hidrogen bonds question

  1. Dec 17, 2009 #1
    1. NH3 ,NH3
    2. H2O , NH3
    3. CH4 ,NH3
    4. CH4 ,CH4
    5. CH3OH ,CH3OH
    6. H2O ,CH3OH
    7. CH3OCH3 ,H2O
    8. CH3OCH3 ,CH3OCH3
    9. CH3OH ,CH3OCH3

    which one of those pair molecules could make hydrogen bonds?
    i know i law
    that H bonds with N O F
    so its 1 2 3 5 6 7 8 9 pairs

    but the book says 1 2 5 6 7 9

    why??
     
  2. jcsd
  3. Dec 17, 2009 #2
    3. CH4 ,NH3 CH4 is non polar unable to react with the polar NH3.
    4. CH4 CH4 definity no polarity here and no functional groups so I can not see the H bonds anywhere and they are same molecule thus I think there is no reaction
    8. CH3OCH3 ,CH3OCH3 same as 4

    1. NH3 ,NH3 Very polar molecule thus H bonds from N to H due the extremely electronegative N. Note this is not a bond but merely a intermolecular force.
    2. H2O , NH3 -H of H20 to N of NH3 and O of H20 to H of NH3 because both O and N are extremely electronegative thus creating polarity and thus in turn results in H bonds
    5. CH3OH ,CH3OH - Hydroxy functional group (-OH) of ethanol are extremely polar thus electronegative thus they are able to form H bonds
    6. H2O ,CH3OH - Hydroxy functional group(-OH).....
    7. CH3OCH3 ,H2O - Hydroxy functional group(-OH),.....
    9. CH3OH ,CH3OCH3 Hydroxy functional group(-OH)....

    I think it is because of they are all non-polar molecules thus unable to react N O F to produce H bonds. Because non polar molecules can not react with polar molecules and since N O F have extremely high electronegativity they are almost always polar molecules.
    Erhh.. better ask someone better im just a student at high school learnt this stuff like couple months ago. I tried best sorry for any mistakes. =]
     
    Last edited: Dec 17, 2009
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