The solubility of $PbCl_2$ is given by:

Assign $A, B, C, D$ from the given type of reaction.
$CaCl_2 + Na_2C_2O_4 \longrightarrow CaC_2O_4\downarrow + 2NaCl$

Explain the relationship between solubility $(S)$ and solubility product constant $(K_{sp})$.

If the solubility product of $PbS$ is $8 \times 10^{-28}$,then the solubility of $PbS$ in pure water at $298 \ K$ is $x \times 10^{-16} \ mol \ L^{-1}$. The value of $x$ is $\dots$.
[Given $\sqrt{2} = 1.41$]

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

Find the concentration of the ion which is first precipitated at the point when the third ion starts precipitating,if $AgNO_3$ is added gradually to a solution that contains $0.1 \ M \ Cl^{-}$,$0.1 \ M \ Br^{-}$,and $0.1 \ M \ I^{-}$.
Given that:

Salt	$K_{sp}$
$AgCl$	$2 \times 10^{-10}$
$AgBr$	$5 \times 10^{-13}$
$AgI$	$9 \times 10^{-17}$