Có 4 dung dịch muối riêng biệt: CuCl2, ZnCl2, FeCl3, AlCl3

1. CuCl₂

$$\begin{gathered} KOH + CuC{l}_2 \to Cu(OH{)}_2 + 2KCl \\ Cu(OH{)}_2 + 4N{H}_3 \to [ Cu(N{H}_3{)}_{4 }\left]\right(OH{)}_2 \end{gathered}$$  

2. ZnCl₂

 $$\begin{gathered} KOH + ZnC{l}_2 \to Zn(OH{)}_2 + 2KCl \\ Zn(OH{)}_2 + 4N{H}_3 \to \left[Zn\right(N{H}_3{)}_4\left]\right(OH{)}_2 \end{gathered}$$ 

3. FeCl₃

$KOH + FeC{l}_3 \to Fe(OH{)}_3\downarrow + 3KCl$ 

4. AlCl₃

$$\begin{gathered} KOH + AlC{l}_3\to Al(OH{)}_3\downarrow + 3KCl \\ KOH + Al(OH{)}_3 \to KAl{O}_{2 }+ 2H_{2}O \end{gathered}$$