In qualitative analysis, the metals of Group-I can be separated from other ions by precipitating them as chloride salts. A solution initially contains `Ag^+` and `Pb^(2+)` at a concentration of 0.10 M. Aqueous HCl is added to this solution until the `Cl^-` concentration is 0.10 M. What will the concentrations of `Ag^+` and `Pb^(2+)` be at equilibrium ? (`K_(sp)` for AgCl = `1.8xx10^(-10)` , `K_(sp)` for `PbCl_2=1.7xx10^(-5)` )

Options

A. `[Ag^+]=1.8xx10^(-7) M , [Pb^(+2)]=1.7xx10^(-6)` M
B. `[Ag^+]=1.8xx10^(-11) M , [Pb^(+2)]=8.5xx10^(-5)` M
C. `[Ag^+] = 1.8xx10^(-9)M , [Pb^(+2)]=1.7xx10^(-3)` M
D. `[Ag^+]=1.8xx10^(-11) M, [Pb^(+2)]=8.5xx10^(-4)` M

Answer

C

Explanation

`K_(sp)=[Ag^+][Cl^-]`
`1.8xx10^(-10)= [Ag^+][0.1]`
`[Ag^+]= 1.8xx10^(-9)` M
`K_(sp)=[Pb^(+2)][Cl^-]^2`
`1.7xx10^(-5) = [Pb^(+2)][0.1]^2`
`[Pb^(+2)]=1.7xx10^(-3)` M