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Homework Help: HCl with Ca(OH)2

  1. Aug 19, 2012 #1
    1. The problem statement, all variables and given/known data

    I'm trying to understand what happens, chronologically, when 2mol HCl is mixed with 1mol Ca(OH)2 in aqueous solution. Also, is the resulting solution acidic or alkaline.

    2. Relevant equations

    [tex]2HCl + Ca(OH)_2 = 2H^+ + 2Cl^- + Ca^{2+} + 2(OH)^- = ?[/tex]

    3. The attempt at a solution

    I think the H ion will combine with the OH's to make water, but I don't know what happens to the Cl and Ca ions. If they remain unbonded and just float around in the water, then I don't know what effect this has on pH. They don't donate H, obviously, but they don't covalently bond with it either.
  2. jcsd
  3. Aug 20, 2012 #2


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    Staff: Mentor

    You are right - CaCl2 stays dissociated and doesn't affect pH (well, to some extent it does, but that's most likely not important here). Think just in terms of excess reagent.
  4. Aug 20, 2012 #3


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    Gold Member

    Calcium and Chloride ions are present in aqueous solution (Corrected). Chloride Ions are neutral, so are Calcium ions.

    We can also see it as a strong acid HCl reacting with Ca(OH)2, which is also quite strong, so the resultant salt is quite neutral.
    Last edited: Aug 21, 2012
  5. Aug 21, 2012 #4


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    Staff: Mentor

    Please elaborate, what you wrote doesn't make much sense to me. Calcium chloride is quite soluble, tens of grams in 100 mL of water (even more than NaCl).
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