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Homework Help: Making a buffer

  1. Oct 11, 2005 #1
    I need help solving this problem

    Acetic acid has a pka of 4.8. If you are making up a concentrated stock solution of 1M Sodium acetate buffer at pH 4.8, starting with acetic acid, how many ml of 10N NaOH will you have to add?

    first 10N NaOH is the same thing as 10M right, I never learned those units and dont know what they are.

    This is the equation that I came up with for the reaction
    CH3COOH + NaOH --> CH3COO- + H2O

    I really dont know how to go about doing this problem, I am thinking that i need to use the Henderson-Hasselbalch equation which will tell me the concentration of the acetic acid. Can some one point me in the right direction because i really dont know what to do after that.

  2. jcsd
  3. Oct 12, 2005 #2


    User Avatar

    Staff: Mentor

    Read about normality.

    Yes, you have to use H-H equation. Calculate ratio of CH3COO- and CH3COOH. Then assume that all CH3COO- are from neutralized acetic acid - and calculate amount of NaOH needed for this neutralization.
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