Which compound gives a black color with $NH_4OH$?

Match List-$I$ with List-$II$:

List-$I$ ($Test$/$reagent$)	List-$II$ ($Radical$ $identified$)
$A$. Lake Test	$I$. $NO_3^{-}$
$B$. Nessler's Reagent	$II$. $Fe^{3+}$
$C$. Potassium thiocyanate	$III$. $Al^{3+}$
$D$. Brown Ring Test	$IV$. $NH_4^{+}$

Choose the correct answer from the options given below:

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

Which reagent can be used to identify nickel ion $(Ni^{2+})$?

Which ion will form a precipitate with both $HCl$ and $H_2S$?

$(Yellow\,ppt)\,T \xleftarrow{{{K_2}Cr{O_4}}} X$ $\xrightarrow{{dil.\,HCl}} Y(Yellow\,ppt) + Z \uparrow (pungent\,smelling\,gas)$. If $X$ gives green flame test,then $X$ is: