Which of the following is most soluble in water?

The $K_{sp}$ of $Mg(OH)_2$ is $1.2 \times 10^{-11}$. Calculate its solubility in pure water.

On adding $0.1 \ M$ solution each of $[Ag^+]$,$[Ba^{2+}]$,and $[Ca^{2+}]$ to a $Na_2SO_4$ solution,which species precipitates first? Given: $K_{sp}(BaSO_4) = 10^{-11}$,$K_{sp}(CaSO_4) = 10^{-6}$,$K_{sp}(Ag_2SO_4) = 10^{-5}$.

At $298 \ K$ temperature,the $K_{sp}$ of $Mg(OH)_2$ is $1.8 \times 10^{-11}$. If $0.1 \ M$ $NaOH$ solution is added to it,what is the concentration of $Mg^{2+}$ ions? Calculate its solubility in water.

For $AgCl$,$K_{sp} = 1.2 \times 10^{-10}$ and for $AgBr$,$K_{sp} = 3.5 \times 10^{-13}$. What is the relationship between their solubilities $(S)$?

Concentration of the $Ag^{+}$ ions in a saturated solution of $Ag_2C_2O_4$ is $2.2 \times 10^{-4} \ mol \ L^{-1}.$ Solubility product of $Ag_2C_2O_4$ is