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Why do H+ ions not react with the atoms/molecules they're originally bonded to?

  1. Jun 22, 2005 #1
    If you dissolve HCl in solution, the why do the H+ and the Cl- not react with one another? The H+ will react with any metal, will react with OH-, will react with your skin for sure, along with many other things, but why does it seem to just ignore a perfectly good negative ion that is in the exact same concentration as it is.
  2. jcsd
  3. Jun 22, 2005 #2
    But it DOES. You have to remember this is hydrogen chloride gas IN solution, which allows Dissociation of the HCl molecule due to Hydration.
  4. Jun 23, 2005 #3


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    Science Advisor

    Yeah, better to think of it as the HCl molecule reacts with water to dissociate the two.
  5. Jun 23, 2005 #4


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    Staff: Mentor

    Hydrogen chloride dissociates in water

    [tex]HCl \leftrightarrow H^+ + Cl^-[/tex]

    dissociation constant for this reaction is

    [tex]K_a = \frac {[H^+][Cl^-]} {[HCl]}[/tex]

    pKa = -4 (see pKa tables at ChemBuddy).

    So in every solution of hydrochloric acid you may expect minute amounts of undissociated HCl - but as the Ka constant is large, these will be VERY minute.
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