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Two hydroxides doesn't matter in this problem

  1. Jan 27, 2008 #1
    I'm having trouble understanding why the fact that there are two hydroxides doesn't matter in this problem.

    What volume of 0.150-molar HCl is required to neutralize 25.0 milliliters of 0.120-molar Ba(OH)2?

    I thought the setup would look like this simple enough:

    (25.0 mL)(.120 M)(2) = (.150 M)(V)

    and the volume came out to be 40.0 mL. I assumed that the neutralization reaction looked like this:

    2HCl + Ba(OH)2 --> 2H2O + BaCl2

    so for each mole of Ba(OH)2 there would be two moles of HCl. However, I was told the answer was 20.0 mL. Why is the presence of two hydroxides negligible, or is the answer I was given incorrect?
  2. jcsd
  3. Jan 28, 2008 #2
    First of all, work out the reaction, what is the stoichiometric ratio of this reaction.

    Secondly, work out the number of moles in both substances
    then it should be basic plugging and chugging.
  4. Jan 28, 2008 #3
    I see nothing wrong with this. For each mole of Ba(OH)2 you need
    2 moles of HCl to neutralize it. V=40 mL.
  5. Jan 28, 2008 #4
    Thanks for the replies. I had it confirmed with my teacher today and he simply made a mistake when grading the test. ;)
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