Equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate are mixed together. Will it lead to precipitation of copper iodate? (For cupric iodate Ksp = 7.4 × 10–8).
Given:
Ksp of cupric iodate = 7.4 × 10–8
Equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate are mixed together.
Ionization of sodium iodate:
2NaIO3 + CuCrO4 Na2CrO4 + Cu(IO3)2
After mixing, [NaIO3] = [IO3-] = = 10-3M
[CuCrO4] = [Cu2+] = = 10-3M
For cupric iodate, the ionization is:
Cu(IO3)2 ↔ [Cu2+][IO3-]
As we know that,
Ksp = [A+] [B-]
Where A and B are the ions dissolved
In the above reaction,
⇒[A+] = [Cu2+]
⇒[B-] = [IO3-]
∴ Ksp = [Cu2+][IO3-]
⇒Ksp = (10-3)(10-3)
⇒Ksp = 10-9
As we know that precipitation only occur when Ksp < [A+][B-]
As ionic product 10-9 is less than the Ksp (7.4 × 10–8), hence no precipitation will occur.