Given Ksp, how can I calculate solubility?

I'm told the Ksp of CdF_2 is 6.44\times10^-3 and asked to determine the solubility. How would I go about doing this?

Thanks!

1 Answer
Mar 10, 2018

K_"sp" is a quantitative measure of a solid's solubility in solution.

Consider,

CdF_2(s) rightleftharpoons Cd^(2+)(aq) + 2F^(-)(aq)

where, K_"sp" = [Cd^(2+)][F^-]^2 = 6.44*10^-3

Moreover, consider that for every portion of cadmium ions that dissolve, two portions of fluoride ions will dissolve, such that at equilibrium,

K_"sp" = x * (2x)^2 = 6.44*10^-3

Hence,

therefore x approx 0.117M

is the approximate solubility of cadmium (II) fluoride give your data.