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

The solubility product of $AgCl$ is $1 \times 10^{-6}$ at $298 \, K$. Its solubility in $mol \, L^{-1}$ would be:

The solubility of salt $BA_2$ is $4 \times 10^{-4} \ mol \ dm^{-3}$. What is the solubility product of the salt?

The solubility product of $M(OH)_2$ is $10^{-14}$. What will be the concentration of $M^{+2}$ in a $0.1 \, M$ solution of $NH_4OH$,if $NH_4OH$ is $10\%$ ionized?

At $25\,^{\circ}C$,the solubility product of $Mg(OH)_2$ is $1.0 \times 10^{-11}$. At which $pH$ will $Mg^{2+}$ ions start precipitating in the form of $Mg(OH)_2$ from a solution of $0.001\, M\, Mg^{2+}$ ions?

$A$ $2.901 \ L$ saturated solution is formed by $0.08 \ g$ of $CaF_2$ at $298 \ K$. Calculate the $K_{sp}$ of $CaF_2$. (Molar mass of $CaF_2$ is $78 \ g \ mol^{-1}$)