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Homework Help: Question about getting the pH

  1. Apr 24, 2009 #1
    1. The problem statement, all variables and given/known data
    What will be the final pH of the solution if a drop (approximately equal to 1/20 mL) of 1.0M HCl is added to a 10mL 0.1 M CH3COOH sol'n?

    2. Relevant equations
    pH = -log [H+]

    3. The attempt at a solution
    I first determined the number of moles of H+ from the partial ionization of CH3COOH (CH3COOH <--> CH3COO- + H+) using the ICE table. The number of moles H+ from my computation is 4.024922359 x 10^-5.

    Then I also determined the number of moles of H+ from HCl--> H+ + Cl-. What I got is 5 x 10^-5 moles.

    I added the two values to get the total number of moles H+.

    The pH I got is 2.52.

    Is my answer correct?
    I'm not quite sure about how I solved it.
    Need help. Thanks. :smile:
  2. jcsd
  3. Apr 24, 2009 #2
    How do I apply the common-ion effect for this problem?
  4. Apr 25, 2009 #3


    User Avatar

    Staff: Mentor

    Do an ICE table for acetic acid treating H+ from HCl as initial concentration.
  5. Apr 25, 2009 #4
    Thanks much. I'll do that.
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