Chapter 15, Problem 15.30P

Interpretation Introduction

Interpretation:

Naturally occurring carotene primarily exists in two different forms, called $\text{α-Carotene}$ and $\text{β-Carotene}$. Which form has the longer-wavelength is to be explained.

Concept introduction:

${\lambda }_{\max }$ depends heavily on the extent of conjugation. In a molecule that contains only one sigma bond and does not absorb UV or visible regions- the ${\lambda }_{\max }$ is too much smaller. On the other hand, a molecule that contains at least one pi bond and has greater ${\lambda }_{\max }$ than about nearly $\text{160 nm}$, the value of the longest-wavelength ${\lambda }_{\max }$ increases as the extent of conjugation increases.