Which of the following is not precipitated as sulphide by passing $H_2S$ in the presence of concentrated $HCl$?

Reagents used for the qualitative estimation of $Ni^{+2}$ and $Cu^{+2}$ respectively are:

Nessler's reagent is used to detect

What is formed when calomel $(Hg_2Cl_2)$ reacts with $NH_4OH$?

$A$ (Orange color compound) $\xrightarrow{(B) + \text{conc. } H_2SO_4}$ $C$ (Red gas) $\xrightarrow{NaOH + AgNO_3}$ $D$ (Red ppt.) $\xrightarrow{\text{NH}_3 \text{ solution}}$ Yellow solution.
$B$ $\xrightarrow[\Delta]{NaOH}$ $F \uparrow$ (Gives white fumes with $HCl$).
Identify $B$ and $F$ respectively :-

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