Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$HgS \downarrow + HNO_3 \text{ (Conc.)} \longrightarrow \text{No dissolution}$

Solid $Ba(NO_3)_2$ is gradually dissolved in $1.0 \times 10^{-4} \, M \, Na_2CO_3$ solution. At which concentration of $Ba^{2+}$ will the precipitation begin? $(K_{sp} \, BaCO_3 = 5.1 \times 10^{-9})$

Calculate solubility $(mol \ dm^{-3})$ of a sparingly soluble electrolyte $AB$ at $298 \ K$ if its solubility product is $1.6 \times 10^{-5}$?

Solubility products $(K_{sp})$ of the salts of types $MX, MX_2$ and $M_3X$ at temperature $T$ are $4.0 \times 10^{-8}, 3.2 \times 10^{-14}$ and $2.7 \times 10^{-15}$ respectively. Solubilities (in $mol \text{ dm}^{-3}$) of the salts at temperature $T$ are in the order:

For the precipitation reaction of $Ag^{\oplus}$ ions with $NaCl,$ which of the following statements is true?

$25.0 \ mL$ of $0.050 \ M \ Ba(NO_3)_2$ is mixed with $25.0 \ mL$ of $0.020 \ M \ NaF$. The $K_{sp}$ of $BaF_2$ is $0.5 \times 10^{-6}$ at $298 \ K$. The ratio of $[Ba^{2+}][F^{-}]^2$ to $K_{sp}$ is $.......$. (Nearest integer)