Question

(a) Discuss the effect of conjugation and steric hindrance
on the position of absorption bands in UV spectra.
(8)​

Answer 1

Answer:  The effect of increasing conjugation is to shift the spectrum toward longer wavelength (lower frequency, lower energy) absorptions. Figure 2.15. Ultraviolet absorption spectrum of 1,3-butadiene.

Explanation:  By extending conjugation, the wavelength of absorption is shifted to higher value. The position and intensity is greatly affected by the polarity of solvent. The temperature, concentration and pH of the sample solution affect the position and shape of UV-Vis absorption bands.