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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: kimi85 on July 16, 2007, 08:21:55 PM

Title: calculating Ksp
Post by: kimi85 on July 16, 2007, 08:21:55 PM

A saturated solution of silver benzoate AgOCOC₆H₅, has a pH of 8.63. Ka for benzoic acid is 6.5 x 10^-5.  Estimate the value of Ksp for silver benzoate.  The correct answer is 1.44 x 10^-2 but I can't get to that..

Title: Re: calculating Ksp
Post by: kimi85 on July 16, 2007, 09:01:33 PM

I got it. My answer is just close enough. It's 1.40 x 10^-2.
This is what I did: I calculate the molar concentration of OH- from the given pH. Then I input it in the ICE table which is

C6H5COO- + H2O -->        C6H5COOH +       OH-
x - 4.26 x 10^-6 +4.26 x 10^-6    + 4.26 x 10^-6

Then, I calculate x. x squared is the Ksp.