Nessler's reagent is

$X_2S_n + H_2O \to X(OH)_n \downarrow + Y \uparrow (Gas) \xrightarrow{Pb(CH_3COO)_2} Z \downarrow (Black \ ppt.)$
Then $(X)$ cation can not be

$A$ nitrate when mixed with common salt gives a white precipitate which is soluble in dilute $NH_4OH$. It is the nitrate of

In a solution containing $Hg^{2+}, Cd^{2+}, Sr^{2+}, Fe^{2+},$ and $Cu^{2+}$ ions in $0.3 \, M \, HCl$,which ions will precipitate upon the addition of $H_2S$?

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

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