UV-VIS Spectrum:

i) An absorption in the UV-VIS region of the spectrum, that is the UV-VIS spectrum of a molecule indicates the presence of certain functional groups that have characteristic n → π *, π → π * transitions. These transitions are so characteristic that the absence of a UV-VIS spectrum for a molecule eliminates the presence of a number of functional groups in the molecule.

ii) The λ _max and the intensity of the absorption bands are indicative of the extent of conjugation in the molecule; larger the wavelength, greater the conjugation.