Which of the following is soluble in yellow ammonium sulphide?

Which radicals are precipitated by $(NH_4)_2CO_3$ in the presence of $NH_4OH$ (alkali)?

In the group analysis of cations, $Ba^{2+}$ and $Ca^{2+}$ are precipitated respectively as

$A$ 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 $Hg(NO_3)_2$

Which of the following ions form precipitates when $H_2S$ gas is passed through an acidic mixture containing $Cu^{2+}, Ni^{2+},$ and $Zn^{2+}$?

Nessler's reagent is used to detect