Question

Calculate the concentration of IO3– in a 9.23 mM Pb(NO3)2 solution saturated with Pb(IO3)2. The Ksp of Pb(IO3)2 is 2.5 × 10-13. Assume that Pb(IO3)2 is a negligible source of Pb2 compared to Pb(NO3)2.

Answer 1

Pb(NO3)2 => Pb2+ + 2 NO3-
[Pb2+] = [Pb(NO3)2] = 7.77 mM = 7.77 x 10-3 M

Pb(IO3)2 <=> Pb2+ + 2 IO3-
Ksp = [Pb2+][IO3-]2 = 2.5 x 10-13
7.77 x 10-3 x [IO3-]2 = 2.5 x 10-13
[IO3-] = 5.67 x 10-6 M ˜ 5.7 x 10-6 M

Answer 2

replace the 7.77 with 9.23
answer in end in 5.20 x 10^-6

Answer 3

I agree with the last answer.