Calculate the solubility product of `Co_(2)[Fe(CN)_(6)]` in water at `25^(@)C`.
Given, conductivity of saturated solutions of `Co_(2)[Fe(CN)_(6)]` is `2.06 xx 10^(-6) Omega^(-1)cm^(-1)` and that of water used is `4.1 xx 10^(-7) Omega^(-1)cm^(-1)`. The ionic molar conductivities of `Co^(2+)` and `[Fe(CN)_(6)]^(4)` are `86.0 Omega cm^(2)mol^(-1)` and `444.0 Omega^(-1) cm^(2)mol^(-1)`, respectivly.

Options

A. `7.87xx10^(-7)`
B. `7.87xx10^(-6)`
C. `7.87xx10^(-8)`
D. `7.87xx10^(-9)`

Answer

a

Explanation

`k_(Co_(2)[Fe(CN)_(6)])=2.06xx10^(-6)=0.41xx10^(-6)=1.65xx10^(-6)`
`wedge_(mCo_(2)[Fe(CN)_(6)])=2wedge_(m)Co^(2+)+wedge_(m)[Fe(CN)_(6)]^(4-)`
`implieswedge_(m)=1000(k)/(c)impliesc=2.7xx10^(-6)M`
`implies K_(spCo_(2)[Fe(CN)_(6)])=4c^(3)=7.87xx10^(-17)M^(3)`