Concentrated aqueous sodium hydroxide can separate a mixture of

In the analysis of basic radicals,the group reagent $H_2S$ gas is generally used in which groups?

Which of the following statement$(s)$ is(are) correct with reference to the ferrous and ferric ions?

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

An inorganic compound $X$ on treatment with concentrated $H_{2}SO_{4}$ produces brown fumes and gives a dark brown ring with $FeSO_{4}$ in the presence of concentrated $H_{2}SO_{4}$. Also,compound $X$ gives a precipitate $Y$ when its solution in dilute $HCl$ is treated with $H_{2}S$ gas. The precipitate $Y$ on treatment with concentrated $HNO_{3}$ followed by excess of $NH_{4}OH$ further gives a deep blue coloured solution. Compound $X$ is:

On saturating an aqueous solution of $Cu(II)$,$Pb(II)$,and $Zn(II)$ ions with $H_2S$,which of the following will precipitate?