Which compound does not dissolve in acetic acid?

At $20\,^oC$,the concentration of $Ag^{+}$ in a saturated solution of $Ag_2CrO_4$ is $1.5 \times 10^{-4}\,mol\,L^{-1}$. The solubility product of $Ag_2CrO_4$ at $20\,^oC$ is .......

Assign $A, B, C, D$ from the given type of reaction.
$AlCl_3 + 3NaOH \longrightarrow Al(OH)_3 \downarrow + 3NaCl$

$A$ precipitate of $AgCl$ is formed when equal volumes of the following are mixed. [$K_{sp}$ for $AgCl = 10^{-10}$]

What would be the concentration of $H_2SO_4$ necessary to precipitate $BaSO_4$ from a solution of $0.01 \ M \ Ba^{2+}$ ions $(K_{sp} = 1.0 \times 10^{-9})$?

When equal volumes of the following solutions are mixed,precipitation of $AgCl$ will occur in - ($K_{sp}$ of $AgCl = 1.8 \times 10^{-10}$)