What is the solubility (in $mol \ L^{-1}$) of $AgCl$ $(K_{sp} = 1.0 \times 10^{-10})$ in a $0.1 \ M \ Cl^-$ solution?

Among different types of sparingly soluble salts having nearly the same solubility product constants $(K_{sp})$,the least soluble salt is that which:

Using the Gibbs energy change,$\Delta G^{o} = +63.3 \ kJ \ mol^{-1}$,for the following reaction in water at $25 \ ^{\circ}C$,calculate the solubility product constant $(K_{sp})$:
$Ag_{2}CO_{3(s)} \rightleftharpoons 2Ag^{+}_{(aq)} + C{O_{3}}^{2-}_{(aq)}$
$(R = 8.314 \ J \ K^{-1} \ mol^{-1})$

The solubility product of $AgCl$ at $25 \, ^\circ C$ is $5 \times 10^{-13}$. Its solubility is = .......

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

Assign $A, B, C, D$ from the given type of reaction.
$ZnS(s) + 2HCl(aq) \longrightarrow ZnCl_2(aq) + H_2S(g)$