# How do you calculate Ksp if given molar solubility?

Jun 27, 2016

I wil give you an example with regard to ${K}_{s p}$ of $\text{silver bromide}$.

#### Explanation:

Write the solubility expression:

$A g B r r i g h t \le f t h a r p \infty n s A {g}^{+} + B {r}^{-}$

Now the solubility of $A g B r$ under standard conditions is reported as $5.71 \times {10}^{-} 7$ $m o l \cdot {L}^{-} 1$.

Given the solubility, $\left[A g B r\right] = \left[A {g}^{+}\right] = \left[B {r}^{-}\right]$

And ${K}_{s p}$ is simply the equilibrium expression, $\left[A {g}^{+}\right] \left[B {r}^{-}\right]$ $=$ ${\left(5.71 \times {10}^{-} 7\right)}^{2}$ $=$ ??