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Homework Help: Ionization Problem

  1. Feb 16, 2009 #1
    1. The problem statement, all variables and given/known data

    A 0.085 M aqueous solution of a weak base is known to be 1.6 percent ionized. Calculate the pH of the solution.



    2. Relevant equations

    %Ionization= ([OH-] derived from base/ initial [base]) x 100%
    pOH=-log[OH-}


    3. The attempt at a solution

    %Ionization= ([OH-] derived from base/ initial [base]) x 100%
    1.6%=[OH]/0.085M
    [OH]=0.136M

    pOH=-log[OH-]
    pOH=-log(o.136M)
    pOH=0.866
    pH+pOH=14, 14-0.866=13.134...

    I normally do these without a problem, so I'm assuming it's a stupid mistake. The problem clearly says weak base...Where am I going wrong?

    Regards,
    Fragment
     
  2. jcsd
  3. Feb 17, 2009 #2

    Borek

    User Avatar

    Staff: Mentor

    Check your math. You are right - it is a stupid mistake. Not that uncommon though.
     
  4. Feb 17, 2009 #3
    Hahaha, I even double checked it the other night. How lame. Thanks:redface:
     
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