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Solution stoichometry, attempted ANSWER IS WRONG, can anyone fix answer

  1. May 14, 2010 #1
    A 15.0 mL sample of an unknown H3PO4 solution requires 110 mL of 0.120 M KOH to completely react with the H3PO4 according the following reaction.

    H3PO4 + 3KOH --------> 3H20 + K3PO4

    What was the concentration of the unknown H3PO4 solution?


    This SEEMED correct way to start problem, as it turns out this is not how to set up the problem, (attempt at doing the problem) : 15mL converted that to L , got 0.015 L, then multiplied that by .12 moles of the solute KOH divided by 1 Liter of the solution H3PO4, used the mole to mole conversion 3 moles of KOH to every 1 mole of H3PO4 and got the wrong answer. It's supposed to be
    .293 Molarity.

  2. jcsd
  3. May 14, 2010 #2
    You have to do the three dissociation reactions separately.
  4. May 15, 2010 #3


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    Staff: Mentor

    15 mL is the volume of acid, not base.

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