Aqueous solution of $FeSO_4$ does not produce a precipitate with:

$Pb^{2+}$,$Cu^{2+}$,$Zn^{2+}$,and $Ni^{2+}$ ions are present in a given acidic solution. On passing hydrogen sulphide gas through this solution,the precipitate formed will contain:

Which compound is used to distinguish between $Fe^{2+}$ and $Fe^{3+}$ ions?

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

When $H_2S$ is passed through a solution in $Group-II$ analysis,it sometimes becomes milky. This indicates the presence of:

When $H_2S$ gas is passed through the $HCl$ containing aqueous solutions of $CuCl_2$,$HgCl_2$,$BiCl_3$ and $CoCl_2$,which does not precipitate out?