`HgCrO_(4)` just begins to peripitate when equal volumes of `4 xx 10^(-4)M Hg_(2)(NO_(3))_(2)` and `2 xx 10^(-5)M K_(2)CrO_(4)` are combind. What is the approximate `K_(sp)` value of `Hg_(2)CrO_(4)`?

Options

A. `1 xx 10^(-18) mol L^(-1)`
B. `8 xx 10^(-9)mol L^(-1)`
C. `2xx 10^(-9) mol L^(-1)`
D. `4 xx 10^(-9) mol L^(-1)`

Answer

B

Explanation

`Hg_(2)CrO_(4)hArr Hg_(2)^(2+) +CrO_(4)^(2-)`
`[Hg_(2)^(2+)]= 4 xx 10^(-4)M, [CrO_(4)^(2-)] = 2xx 10^(-5)`
`K_(sp) = (4 xx 10^(-4)) (2xx 10^(-5)) = 8 xx 10^(-9)`