Which of the following sulphides is yellow in colour?

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

If $Pb^{2+}, Cu^{2+}, Al^{3+}, Cd^{2+}, Zn^{2+}$ radicals are present in an aqueous solution,and it reacts with $H^{+}/H_2S$,a precipitate is produced. The solution $(X)$ obtained after the removal of the precipitate is treated with excess $NaOH$. What is the result?

The ion that can be precipitated by $HCl$ as well as $H_2S$ is

The reagent used for the identification of $Ni^{2+}$ ions is .....

An aqueous solution contains the ions as $Hg_2^{2+}$,$Hg^{2+}$,$Pb^{2+}$,and $Cd^{2+}$. The addition of dilute $HCl$ $(6 \ N)$ precipitates: