Question

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!

Answer 1

`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.