Find the compound $A$ from the following reaction sequences:
$A$ $\xrightarrow{\text{aqua-regia}} B$ $\xrightarrow[(2) CH_3COOH]{(1) KNO_2 \mid NH_4OH} \text{yellow ppt}$

Consider the following reaction scheme: $D(\text{White ppt}) \xleftarrow{Na_2CO_3} A \xrightarrow[\text{in acetic acid}]{K_2CrO_4} B(\text{Yellow ppt})$ and $A \xrightarrow{dil.\ H_2SO_4} C(\text{White ppt})$. If $A$ is a metallic salt,then the white precipitate $D$ must be:

Which of the following radicals will not be precipitated by passing $H_2S$ in a concentrated acid solution?

When $H_2S$ gas is passed through a solution,it reacts to form a white precipitate. Which ion is present in the solution?

Among $PbS$,$CuS$,$HgS$,$MnS$,$Ag_2S$,$NiS$,$CoS$,$Bi_2S_3$,and $SnS_2$,the total number of black coloured sulphides is

Sometimes yellow turbidity appears on passing $H_2S$ gas even in the absence of the second group radicals. This happens because