Answer:
Analyzing the wavelength of maximum absorbance
Explanation:
Using spectrophotometry during the course of the reaction can confirm that the reaction took place.
The complex [Cu(NH₃)₄]²⁺ has a characteristic wavelength of maximum absorbance ( [tex]λ_{max}[/tex] ), which can be looked up in literature. This characteristic λmax is different from the characteristic λmax of the reagents, as [Cu(NH₃)₄]²⁺ absorbs red-orange light and thus appears with a deep blue-violet color.
