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

$K_{sp}$ for $CaSO_4$ is $9 \times 10^{-6}$. The minimum volume of water needed to dissolve $1 \ g$ of $CaSO_4$ at $298 \ K$ temperature is ...... (in $L$)

If the solubility product of $CuS$ is $6 \times 10^{-16}$,calculate the maximum molarity of $CuS$ in aqueous solution.

$A$ sparingly soluble salt having general formula $A_{x}B_{y}$ and molar solubility $S$ is in equilibrium with its saturated solution. Derive a relationship between solubility and the solubility product for such salt.

Solubility of $AgCl$ in $0.2 \, M \, NaCl$ is $x$ and that in $0.1 \, M \, AgNO_3$ is $y$. Then which of the following is correct?

At $298 \ K$,the solubility of silver chloride in water is $1.434 \times 10^{-3} \ g \ L^{-1}$. The value of $-\log K_{sp}$ for silver chloride is $........$ (Given: molar mass of $Ag = 107.9 \ g \ mol^{-1}$ and $Cl = 35.5 \ g \ mol^{-1}$)