If $S$ and $K_{sp}$ are respectively solubility and solubility product of a sparingly soluble binary electrolyte,then

What is the $pH$ at which $Mg(OH)_2$ starts to precipitate from a solution containing $0.1 \ M \ Mg^{2+}$ ions? (Given $K_{sp}$ for $Mg(OH)_2 = 1.0 \times 10^{-11}$)

Equal volumes of $0.002 \, M$ solutions of sodium iodate and cupric chlorate are mixed together. Will it lead to precipitation of copper iodate?
(For cupric iodate $K_{sp} = 7.4 \times 10^{-8}$)

The solubility of $PbI_2$ at $25 \, ^\circ C$ is $0.7 \, g \, L^{-1}$. What is the solubility product $(K_{sp})$ of $PbI_2$ at this temperature? (Molar mass of $PbI_2 = 461.2 \, g \, mol^{-1}$)

The solubility product of silver bromide is $5.0 \times 10^{-13}$. The quantity of potassium bromide (molar mass taken as $120 \ g \ mol^{-1}$) to be added to $1 \ L$ of $0.05 \ M$ solution of silver nitrate to start the precipitation of $AgBr$ is

$K_{sp}$ of a salt $Ni(OH)_2$ is $2 \times 10^{-15}$,then molar solubility of $Ni(OH)_2$ in $0.01 \ M \ NaOH$ is $:-$