15.2 Exercise 6

Sometimes equilibria for complex ions are described in terms of dissociation constants, K_d. For the complex ion $\text{AlF}_{6} ^{\text{3}−}$ the dissociation reaction is:

$\text{AlF}_{6} ^{\text{3}−} \rightleftharpoons \text{Al}^{\text{3}+} + 6 \text{F}^{−}$ and $K_{\text{d}} = \frac{\left[\text{Al}^{\text{3}+}\right] \left[\text{F}^{−}\right]^{6}}{\left[\text{AlF}_{6} ^{\text{3}−}\right]} = 2 \times 10^{- 24}$

Calculate the value of the formation constant, K_f, for $\text{AlF}_{\text{6}} ^{\text{3}−} .$