. Ksp for Fe(IO3)3 is 10-14. Two solutions, one being iron(III) nitrate and the other being sodium iodate, were mixed. At the instant of mixing, [Fe3+] = 10-4M and [IO3-] = 10-5M. What happens?

My answer is that a precipitate forms because Qsp > Ksp.

Would you agree?

Chemistry(Please check) - DrBob222, Sunday, April 8, 2012 at 5:02pm
No. Calculate Qsp again. And don't forget to cube IO3^- this time.

How do you calculate Qsp again? Would it be the concentration of Fe^3+ divided by IO3^-^?

1 answer

You calculate Qsp the same way you do Ksp; you just didn't cube the IO3^-.
Fe(IO3)3 ==> Fe^3+ + 3IO3^-
Ksp = (Fe^3+)(IO3^-)^3 or
Qsp = (Fe^3+)(IO3^-)^3 = [1*10^-4][1*10^-5]^3 = 1E-19