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Homework Help: Buffer Solutions adding acid or base

  1. Feb 10, 2008 #1
    1. The problem statement, all variables and given/known data
    A buffer is prepared by dissolving 1.00 mole HLac (with a ka=8.0x10-3) and 1.00 mole of sodium lactate (NaLac) in enough water to form one (1) liter of solution. Calculate the [H+] and the pH of the buffer.
    36 minutes ago - 3 days left to answer.
    Additional Details
    12 minutes ago

    There is another part to this and it says
    Using the information from that problem: supposed we add a strong acid or base to the buffer; calculate the following:
    a. [HLac], [Lac], [H+] and the pH after adding 1L of 0.15 M-HCl
    b. [HLac], [Lac], [H+], and the pH after adding 1L of 0.15M-NaOH

    2. Relevant equations


    3. The attempt at a solution

    I know the answer to the first part is found to be pH=2.1 I just have no idea how to find the part a and b for the second half.
  2. jcsd
  3. Feb 11, 2008 #2
    you can always try writing the equilibrium equation then solve for them using the first principles:

    A + B <-> C
    1 1 0
    1-x 1-x x
    K = x/(1-x)^2 etc
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