The correct option is C 3.1×10−10M
The Ksp values of Ag2CrO4 and AgIO3 reveals that CrO2−4 and IO−3
will be precipitated on addition of AgNO3 as:
[Ag+][IO−3]=10−13
[Ag+]needed=10−13(0.005)=2×10−11M
[Ag+]2[CrO2−4]=10−8
∴ [Ag+]needed=√10−80.1=3.16×10−4M
Thus AgIO3 will be precipiated first.
Now in order to precipitate AgIO3, one can slow.
AgNO30.010.005+NaIO30.0050⟶AgIO300.005+NaNO300.005
The left mole of AgNO3 are now used to precipitate Ag2CrO4
2AgNO30.0050+Na2CrO40.10.0975⟶AgIO300.0025+2NaNO300.005
Thus [CrO2−4] left in solution =0.0975
Now solution has precipitates of AgIO3(s) (0.005mole)+Ag2CrO4(s)(0.0025mole) and CrO2−4 ions (0.0975)
Thus,[Ag+]left=
⎷KspAg2CrO4[CrO2−4]=√10−80.0975=3.2×10−4M
[IO−3]left=KspAgIO3[Ag+]=10−133.2×10−4=3.1×10−10M