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Homework Help: PH of a mixed solution: is this right?

  1. Dec 15, 2006 #1
    1. The problem statement, all variables and given/known data

    What is the final pH of a solution obtained by mixing 200 ml of 0.400 M NH3 with 300 ml of 0.100 M HCl? (Kb = 1.8 x 10^-5)

    2. Relevant equations

    3. The attempt at a solution

    I used an ICE table and came up with 9.68. Is that correct?

    Should I have used two ICE tables instead of one? The first in the one direction and the second going back in the other direction?
     
    Last edited: Dec 15, 2006
  2. jcsd
  3. Dec 16, 2006 #2

    GCT

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    hint: the first reactions is that with NH3 and HCl, if you have excess HCl, then you can simply use the pH equation (pH= -log[H3O+]) to find the resulting pH, if the base is the excess, then the Kb equation is going to be used to determine the [OH-] concentration, and eventually the pH.
     
  4. Dec 16, 2006 #3
    Thank you.
     
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