Which of the following compounds will not dissolve in a hot mixture of $NaOH$ and $H_2O$?

Assign $A, B, C, D$ from the given type of reaction.
$ZnS(s) + 2HCl(aq) \longrightarrow ZnCl_2(aq) + H_2S(g)$

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$CaSO_3 \downarrow + SO_2 + H_2O \longrightarrow Ca(HSO_3)_2$

If the solubility product of $CaSO_4$ is $2.5 \times 10^{-5}$,then its solubility will be .......

$A$ solution is saturated with $SrCO_3$ and $SrF_2$. The $[CO_3^{2-}]$ is found to be $1.2 \times 10^{-3} \ M$. The concentration of $F^{-}$ in the solution would be:
Given: $K_{sp}(SrCO_3) = 7.0 \times 10^{-10}$, $K_{sp}(SrF_2) = 7.9 \times 10^{-10}$

Which of the following has the maximum solubility? ($K_{sp}$ values are given in parentheses.)