[Cu(NH3)4] 2+ solutions exhibit a deep blue-violet color. How can you use spectrophotometry to confirm that this reaction has occurred and that the product formed is in fact tetraamminecopper(lI)sulfate. Would you expect the wavelength of maximum absorbance (λmax) for Cu(NH3)4 2+ to be greater than or less than λ max for Cu(H2O)6 2+? Explain.
In the lab, you will obtain and record the UV-Visible absorption spectrum of the solution and compare it with the standard spectrum of [Cu(NH3)4]2+. If both spectras match then it is confirmed that the ideal product is obtained.
The wavelength of Cu(NH3)4 2+ is less than lamda max for Cu(H2O)6 2+. Thus it absorbs the shorter wavelength yellow light, this is why it has a
deep blue color.