Which among the following salts turns blue litmus red in its aqueous solution?

The solubility product of the sparingly soluble salt $\mathrm{AB}_2$ is $2.56 \times 10^{-10}$ at 298 K . Calculate its solubility in $\mathrm{mol} \mathrm{dm}^{-3}$ at the same temperature?

Calculate the value of dissociation constant of weak acid, which dissociates to $0.01 \%$ in its 0.1 M solution?

The pH of monoacidic base is 10 . Calculate its percentage dissociation in 0.01 M solution at 298 K ?