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Homework Help: Analytical Chemistry involving buffer

  1. Mar 6, 2007 #1
    1. The problem statement, all variables and given/known data

    What volume of 0.200M HCl must be added to 250.0ml of 0.300M sodium mandelate to produce a buffer solution with a pH of 3.37?

    2. Relevant equations
    3. The attempt at a solution

    For 2 and 3, can I use the equation pH = pKa + log [A-/HA]? but for HCl isn't that 100% disassociation? How can we use that if the Ka is not a given value for HCl?

  2. jcsd
  3. Mar 6, 2007 #2


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    Science Advisor
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    Gold Member

    You are correct... Think of the HCl being used only to protonate a portion of the sodium mandelate.
  4. Mar 10, 2007 #3


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    Staff: Mentor

    And assume this protonation is stoichiometric.
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