Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$BaSO_3 \downarrow + SO_2 + H_2O \longrightarrow Ba(HSO_3)_2$

$A$ solution which is $10^{-3} \ M$ each in $Mn^{2+}, Fe^{2+}, Zn^{2+},$ and $Hg^{2+}$ is treated with $10^{-16} \ M$ sulphide ion. If $K_{sp}$ of $MnS, FeS, ZnS,$ and $HgS$ are $10^{-15}, 10^{-23}, 10^{-20},$ and $10^{-54}$ respectively,which one will precipitate first?

The solubility of $AgCl_{(s)}$ with solubility product $1.6 \times 10^{-10}$ in $0.1 \ M \ NaCl$ solution would be

In a qualitative analysis, $Bi^{3+}$ is detected by the appearance of a precipitate of $BiO(OH)(s)$. Calculate the $pH$ when the following equilibrium exists at $298 \text{ K}$:
$BiO(OH)(s) \rightleftharpoons BiO^{+}(aq) + OH^{-}(aq)$,
$K = 4 \times 10^{-10}$
(Given: $\log 2 = 0.3010$)

The molar solubility of $Zn(OH)_{2}$ in $0.1 \, M \, NaOH$ solution is $x \times 10^{-18} \, M$. The value of $x$ is ...... . (Nearest integer)
(Given : The solubility product of $Zn(OH)_{2}$ is $2 \times 10^{-20}$)

If the solubility of salts $M_2X$,$QY_2$,and $PZ_2$ is the same,what is the relationship between their $K_{sp}$ values?