Which of the following compounds is sparingly soluble in ammonia?

The $K_{sp}$ values of $Al(OH)_3$ and $Zn(OH)_2$ are $8.5 \times 10^{-23}$ and $1.8 \times 10^{-14}$ respectively. If $NH_4OH$ is added to a solution containing $Al^{3+}$ and $Zn^{2+}$ ions,which will precipitate earlier?

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.

If $[S^{2-}] = 0.6 \times 10^{-2} \ mol \ m^{-3}$ and $[Hg^{2+}] = [Mn^{2+}] = [Fe^{2+}] = [Zn^{2+}] = 1 \times 10^{-16} \ mol \ m^{-3}$,which of the following will precipitate first in an aqueous solution?

$PbCl_2$ has a maximum concentration of $1.0 \times 10^{-3} \ M$ in its saturated aqueous solution at $25 \ ^oC$. Its solubility in a $0.1 \ M \ NaCl$ solution will be:

If the solubility of $Mg(OH)_2$ is $x \ mol/L$,then its solubility product $(K_{sp})$ is equal to .....