$A$ precipitate is formed when:

If the concentration of $[Ag^{+}]$ in a solution is $1 \times 10^{-6} \ M$,what is the concentration of $[Br^{-}]$? Given that the $K_{sp}$ for $AgBr$ is $4.0 \times 10^{-13}$.

The solubility of a sparingly soluble salt $AB_2$ is $1 \times 10^{-6} \text{ mol/dm}^3$. Calculate its solubility product.

The solubility of $PbF_2$ (formula weight $= 245$) is $0.46 \ g/L$. What is the solubility product?

Concentration of $H_2SO_4$ and $Na_2SO_4$ in a solution is $1 \ M$ and $1.8 \times 10^{-2} \ M$,respectively. Molar solubility of $PbSO_4$ in the same solution is $X \times 10^{-Y} \ M$ (expressed in scientific notation). The value of $Y$ is. . . .
[Given: Solubility product of $PbSO_4$ $(K_{sp})=1.6 \times 10^{-8}$. For $H_2SO_4$,$K_{a1}$ is very large and $K_{a2}=1.2 \times 10^{-2}$]

The solubility product of $Mg(OH)_2$ is $9 \times 10^{-12}$. If the concentration of $Mg^{+2}$ is $0.01 \ M$,then the concentration of $OH^{-}$ is = .....