The colour of copper sulphide is

The qualitative distinction of $ZnSO_4$ and $Al_2(SO_4)_3$ can be done by using the reagent

Which of the following can be used instead of $NH_4Cl$ in the analysis of group $III$ radicals?

Identify $A$,$B$ and $C$ in the given reaction sequence.

Given below are certain cations. Using inorganic qualitative analysis,arrange them in increasing group number from $0$ to $VI$.
$A. Al^{3+}$ $B. Cu^{2+}$
$C. Ba^{2+}$ $D. Co^{2+}$
$E. Mg^{2+}$
Choose the correct answer from the options given below:

When $H_2S$ is passed through a mixture containing $Cu^{2+}$,$Ni^{2+}$,and $Zn^{2+}$ in an acidic solution,which ion will precipitate?