Question

`Pb(IO_(3))_(2)` is a sparingly soluble salt `(K_(sp) = 2.6 xx 10^(-13))`. To `35mL` of `0.15M Pb(NO_(3))_(2)` solution, `15mL` of `0.8M KIO_(3)` solution is added, and a precipiatte of `Pb(IO_(3))_(2)` is formed.
What will be molarity of `Pb^(2+)` ions in the solution after completion of the reactions?
A. `8.4 xx 10^(-10)`
B. `1.6 xx 10^(-10)`
C. `2.8 xx 10^(-10)`
D. `6.1 xx 10^(-10)`

Answer 1

Correct Answer - C
Due to common ion `(IO_(3)^(Theta))` left in the solution, the solubility `Pb(IO_(3))_(2)` decreases
`S = (K_(sp))/((0.03)^(2)) = (2.6xx10^(-13)xx10^(4))/(9)`
`= 0.28 xx 10^(-9) = 2.8 xx 10^(-10)`