$A \xrightarrow{ K_4[Fe(CN)_6] } \text{Blue-white precipitate}$. Which ion is $A$?

The pair$(s)$ of ions where $BOTH$ the ions are precipitated upon passing $H_2S$ gas in the presence of dilute $HCl$,is(are):
$(A) Ba^{2+}, Zn^{2+}$
$(B) Bi^{3+}, Fe^{3+}$
$(C) Cu^{2+}, Pb^{2+}$
$(D) Hg^{2+}, Bi^{3+}$

$A$ precipitate of ....... would be obtained on adding $HCl$ to a solution of $(Sb_2S_3)$ in yellow ammonium sulphide.

Which of the following compounds can produce Rinmann's green with $Co(NO_3)_2$ solution?

$A$ salt on treatment with dil. $HCl$ gives a pungent smelling gas and a yellow precipitate. The salt gives a green flame when tested. The salt solution gives a yellow precipitate with potassium chromate. The salt is:

Which of the following cations does not give a precipitate with $H_2S$ in a neutral medium?