Which of the following precipitates does not dissolve even in a large excess of $NH_4OH$?

Which of the following is insoluble in water?

What is the molar solubility of $Mn(OH)_2$ $(K_{sp} = 4.5 \times 10^{-14})$ in a buffer solution containing equal moles of $NH_4^+$ and $NH_3$ $(K_b = 1.8 \times 10^{-5})$?

The solubility of $CaF_2$ in water is $1.7 \times 10^{-3} \ g/100 \ mL$ at $298 \ K$. Calculate the solubility product $(K_{sp})$ of $CaF_2$. (Molar mass of $CaF_2 = 78 \ g/mol$)

The $K_{sp}$ of $PbI_2$ is $1.4 \times 10^{-8}$. The molar mass of $PbI_2$ is $461 \ g \ mol^{-1}$. The molar mass of $Pb(NO_3)_2$ is $331.9 \ g \ mol^{-1}$. Find the solubility of $PbI_2$ in: $(a)$ $500 \ mL$ of water,$(b)$ $500 \ mL$ of $0.10 \ M \ KI$ solution,$(c)$ What is the weight of $PbI_2$ soluble in $500 \ mL$ of solution containing $1.33 \ g$ of $Pb(NO_3)_2$?

The solubility of $PbCl_2$ is