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Calculating equilibrium constant

  1. May 13, 2008 #1
    1. The problem statement, all variables and given/known data

    Find the eq. constant for the reaction

    CH3COOH (aq) + NO2- (aq) = CH3COO- (aq) + HNO2 (aq)

    3. The attempt at a solution

    I find Ka for the reaction CH3COOH = CH3COO- + H+ and Kb for the reaction NO2- + H+ = HNO2

    But what are the rules then? I try multiplying the constants, but this does not give the correct answer.
     
  2. jcsd
  3. May 13, 2008 #2
    write the K expression for this equilibrium

    then compare it to the Ka expressions for both CH3CO2H AND HNO2
     
  4. May 13, 2008 #3
    I managed to find the correct solution by multiplying Ka1 and the 1/Ka2. Is 1/Ka2 the same av Kb?
     
  5. May 14, 2008 #4

    Borek

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    Staff: Mentor

  6. May 14, 2008 #5
    Did you just happen to work out the numbers and find the right answer or did you see that rearranging the Ka expressions for the acids gave Ka(CH3CO2)/Ka(HNO2) which was equal to the K expression for the original equilibrium?
     
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