Which of the following pairs of ions would be expected to form a precipitate when their dilute solutions are mixed?

$A$ solution which is $10^{-3} \ M$ each in $Mn^{2+}, Fe^{2+}, Zn^{2+},$ and $Hg^{2+}$ is treated with $10^{-16} \ M$ sulphide ion. If $K_{sp}$ of $MnS, FeS, ZnS,$ and $HgS$ are $10^{-15}, 10^{-23}, 10^{-20},$ and $10^{-54}$ respectively,which one will precipitate first?

Which of the following salts is insoluble in water?

If the solubility product of $Zr_3(PO_4)_4$ is denoted by $K_{SP}$ and its molar solubility is denoted by $S$,then which of the following relations between $S$ and $K_{SP}$ is correct?

The solubility product of $PbI_2$ is $1.08 \times 10^{-7}$. Calculate its solubility in $mol \ dm^{-3}$ at $298 \ K$?

What is the solubility of calcium fluoride $(CaF_2)$ in a saturated solution,if its solubility product $(K_{sp})$ is $3.2 \times 10^{-11}$?