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Homework Help: Which substance exhibits the most hydrogen bonding?

  1. Mar 13, 2012 #1
    1. The problem statement, all variables and given/known data

    Which of the following substances exhibits significant hydrogen bonding in the liquid state?

    A) [itex] CH_{2}F_{2} [/itex]
    B) [itex] N_{2}H_{4} [/itex]
    C) [itex] CH_{3}OCH_{3} [/itex]
    D) [itex] C_{2}H_{4} [/itex]
    E) [itex] C_{2}H_{2}[/itex]

    2. Relevant equations

    3. The attempt at a solution

    I know that hydrogen bonding generally only works with hydrogen being attracted to a nonbonding pair on a very electronegative atom (N,F,O and Cl). So only A,B, and C can be the answer. The answer turns out to be B, but I really thought it would be A since flourine is the most electronegative.

    I also don't understand whether being in the liquid state has any bearing on the problem.

    Advice? Thanks for your time!

  2. jcsd
  3. Mar 13, 2012 #2


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    Science Advisor
    2017 Award

    In a hydrogen bond, you must have a hydrogen bond donor and a hydrogen bond acceptor. The donor requires a hydrogen covalently bound to either a fluorine, nitrogen or oxygen. The hydrogen bond acceptor requires a lone pair on a fluorine, nitrogen or oxygen.

    Compound A is capable of acting as a hydrogen bond acceptor, but because the hydrogens are bound to the carbon, it is incapable of acting as a hydrogen bond donor.
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