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

Ka of PBS

  1. Apr 26, 2007 #1
    Anyone know the Ka for Phosphate Buffered Saline (pH 7.4). I have heard that it is 6.2E-8, but the formula says .008M Na2HPO4, .002M KH2PO4. Using Henderson Haselbalch, [H+] = Ka[KH2PO4]/[Na2HPO4] using pH of 7.4, Ka = 1.59E-7. Which one is correct?
  2. jcsd
  3. Apr 26, 2007 #2


    User Avatar

    Staff: Mentor

    pKas - 2.148, 7.199, 12.35. You should take solution ionic strength into account before calculations.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook