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Homework Help: Acid base titration problem. Need Help!

  1. Nov 15, 2005 #1
    How many moles of H3O+ must be added to one liter of a solution to adjust the pH from 7.17 to 5.85?

    Correct answer 1.34E-6 (1.34 * 10-6)

    The correct answer is given, however I would like to know how to do this problem.
  2. jcsd
  3. Nov 15, 2005 #2


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    Staff Emeritus
    Science Advisor

    See definition of pH - http://www.chembuddy.com/?left=pH-calculation&right=pH-definition

    The pH is related to the molar concentration.

    pH = 7.17 yields a molar concentration of 10-7.17 = 6.76 x 10-8 M, or moles/liter

    Now try to find the number of moles in one liter for pH = 5.85.

    Take the difference which gives the number of moles of H+ or H3O+ one needs to add to one liter.
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