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Reactivity of N2 and H2

  1. Jun 9, 2013 #1
    Why would N2 be less reactive than H2?
    I found out that N2 has a three link bond, which partly explains it. But, what else could I add? Unfortunately, nitrogen is more electronegative than hydrogen so I cannot add that as an explanation...
    Could I say that hydrogen needs to lose or gain 1 electron instead of 3 for nitrogen? Could that really describe reactivity? Anything else?
     
  2. jcsd
  3. Jun 9, 2013 #2
    You're on the right track.

    H2 consists of one sigma bond (overlapping s-orbitals). N2 consists of a triple bond composed of one sigma bond and two pi-bonds (overlapping p-orbitals). This triple bond, and the fact that N2 has a full valance shell, means N2 just doesn't want to break apart easily relative to the single bond of H2.

    Quantitatively, H2 has bond dissolution energy of about 436 kJ/mol, and N2 has bond dissolution energy of about 946 kJ/mol. It takes much more energy to break N2 bonds than H2 bonds.
     
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