Solubility product of a salt of AB is `1 xx 10^(-8) M ^(2)` in a solution in which the concentration of `A^(+)` ions is `10^(-3)M`. The salt will precipitate when the concentration of `B^(-)` ions is kept

Options

A. `10^(-6)M`
B. `10^(-5)M`
C. `10^(-4)M`
D. `10^(-7)M`

Answer

B

Explanation

`K_(sp)=1 xx 10^(-8)`
`=[A^(+)][B^(-)]=[10^(-3)][B^(-)]`
The salt will be precipitated if
Ionic product `gt K_(sp)`
`10^(-3) [B^(-)]gt 1 xx 10^(-8)`
`[B^(-)]gt (10^(-8))/(10^(-3)) i.e., [B^(-)] gt 10^(-5) M`.