The `K_(sp)` of `Ag_(2)CrO_(4),AgCl,AgBr` and AgI are respectively, `1.1xx10^(-12),1.8xx10^(-10),5.0xx10^(-13),8.3xx10^(-17)`. Which one of the following salts will precipitate last if `AgNO_(3)` solution is added to the solution containing equal moles of NaCl,NaBr,NaI and `Na_(2)CrO_(4)` ?

Options

A. AgCl
B. AgBr
C. `Ag_(2)CrO_(4)`
D. Agl

Answer

C

Explanation

`K_(sp) " of " Ag_(2)CrO_(4) = 1.1 xx 10^(-12)`
`K_(sp) " of " AgCl = 1.8 xx 10^(-10)`
`K_(sp) " of " AgBr = 5.0 xx 10^(-13)`
`K_(sp) " of Agl" = 8.3 xx 10^(-17)`
`[Ag^(+)]^(2)[C] = 1.1 xx 10^(-12)`
`[Ag^(+)] =sqrt((1.1xx10^(-12))/([C]))`
If we take [C] = 1 then the maximum requirement of `[Ag^(+)]` will be in case of `"Ag"_(2)CrO_(4)`