Identify $A$,$B$ and $C$ in the given reaction sequence.

The reagent used in the qualitative analysis of the $IV^{th}$ group basic radicals is:

On addition of aqueous $NaOH$ to a salt solution,a white gelatinous precipitate is formed,which dissolves in excess alkali. The salt solution contains

Which of these reactions is correct?

Which of the following is an incorrect match for the precipitate (ppt) and its color?

$A$ mixture of two salts is used to prepare a solution $S$,which gives the following results:
White precipitate$(s)$ $\xleftarrow{\text{Dilute } NaOH(aq.) \text{ at Room temperature}}$ $S$ (aq. solution of the salts) $\xrightarrow{\text{Dilute } HCl(aq.) \text{ at Room temperature}}$ White precipitate$(s)$ only
The correct option$(s)$ for the salt mixture is(are):
$A$. $Pb(NO_3)_2$ and $Zn(NO_3)_2$
$B$. $Pb(NO_3)_2$ and $Bi(NO_3)_3$
$C$. $AgNO_3$ and $Bi(NO_3)_3$
$D$. $Pb(NO_3)_2$ and $Hg(NO_3)_2$