What is `[Ag^(+) ]` in a solution made by dissolving both `Ag_2 CrO_4 and Ag_2C_2O_4` until saturation is reached with respect to both salts ? ` [K_(sp) (Ag_2C_2O_4) =2xx 10 ^(-11) , K_(sp) (Ag_2CrO_4) - 2xx10 ^(-12))]`

Options

A. ` 2.80 xx 10^(-4)`
B. ` 7. 6 xx 10^(-5) `
C. ` 6.63 xx 10^(-6)`
D. ` 3 .52 xx 10 ^(-4) `

Answer

D

Explanation

` Ag_2CrO_4 hArr 2Ag^(+) +CrO_4^(_2) `
` " " 2x+2y" " x`
` Ag_2 C_2O_4hArr 2Ag^(+) C_2O_4^(-2)`
` " " 2y+2x" " y`
` (K_(s_(p1)))/(K_(s_(p2)))=(x)/(y) =(2xx 10^(-12))/(2xx 10^(-11)) =0.1`
` 2xx 10 ^(-11) =(2x + 2y)^(2) .y`
` 2 xx 10^(-11) =4.89 y^(3) `
` " " y= 1.6 xx 10^(4) rArr x= 0.16 xx 10^(-14) `
Total ` [Ag^(+) ]=2x +2y =3.52 xx 10 ^(-4)`