Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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?

    Thanks.
     
  2. jcsd
  3. Mar 6, 2007 #2

    chemisttree

    User Avatar
    Science Advisor
    Homework Helper
    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

    Borek

    User Avatar

    Staff: Mentor

    And assume this protonation is stoichiometric.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook