Solubility of $AgCl$ is $7.2 \times 10^{-7} \ mol \ dm^{-3}$. What is its solubility product?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Ag_2CO_3 \downarrow + 2HCl \longrightarrow 2AgCl \downarrow + CO_2 \uparrow + H_2O$

In which of the following solvents will $AgBr$ have the highest solubility?

The values of $K_{sp}$ of two sparingly soluble salts $Ni(OH)_2$ and $AgCN$ are $2.0 \times 10^{-15}$ and $6 \times 10^{-17}$ respectively. Which salt is more soluble? Explain.

Why only $As^{3+}$ gets precipitated as $As_2S_3$ and not $Zn^{2+}$ as $ZnS$ when $H_2S$ is passed through an acidic solution containing $As^{3+}$ and $Zn^{2+}$?

If the concentration of $OH^{-}$ ions in the reaction $Fe(OH)_{3(s)} \rightleftharpoons Fe^{3+}_{(aq)} + 3OH^{-}_{(aq)}$ is decreased by $1/4$ times,then the equilibrium concentration of $Fe^{3+}$ will increase by $......$ times.