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Homework Help: Diverse Ion effect and Activity coefficients problem

  1. Oct 12, 2007 #1
    The question:

    How many grams of Ba(IO3)2 can be dissolved in 700mL of a 0.100M KIO3 solution at 25C? use activity coefficients for this. (Ksp of Ba(IO3)2 =1.57E-9)

    my answer:

    I used this equation: Ksp = (concentration) * (activity coefficient)

    well i found out that my ionic strength of KIO3 is 0.100M and from a chart, i found the respective activity coeff for Ba2+ and IO3-.
    Ba2+ ---> 0.38
    IO3^- ----> 0.775

    Ba(IO3)2 <----> Ba2+ + 2IO3^-
    I 0 x 0.100M
    C +x +2x
    E x 0.100M+2x

    using the equation above,
    Ksp = [Ba2+]*(activity coeff of Ba) * [IO3^-]^2 * (activity coeff of IO3^-)^2
    1.57E-9 = (x)(0.38) * (0.100+2x)^2 * (0.775)^2

    so i solve for X and that would be the concentration of Ba(IO3)2 in mol/L

    BUT, to solve for X, i found it complicated because there would be 3 solutions for X aren't there?? since it's X^3...... so i am confused on what to do.

    help appreciated, Thanks.
  2. jcsd
  3. Oct 12, 2007 #2
    there above numbers below the balanced equation is supposed to be an ICE table
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