Which of the following reactions with $H_2S$ does not produce metallic sulphide?

For a sparingly soluble salt $A_pB_q$,what is the relationship between its solubility $(S)$ and solubility product $(K_{sp})$?

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

Solubility product $(K_{sp})$ of salts of type $MX$,$MX_2$,and $M_3X$ at temperature $T$ are $4 \times 10^{-8}$,$3.2 \times 10^{-14}$,and $2.7 \times 10^{-15}$ respectively. The solubility of the salts at temperature $T$ are in the order:

Solubility of an $MX_2$ type electrolyte is $0.5 \times 10^{-4} \ mol/L$,then $K_{sp}$ of electrolyte is

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$AgCl \downarrow + 2KCN \longrightarrow K[Ag(CN)_2] + KCl$