Which of the following compounds absorbs the longest wavelength of UV-visible light?
A) (E)-but-2-ene
B) (Z)-but-2-ene
C) hex-1-ene
D) (Z)-1,3-hexadiene
E) (E)-1,3,5-hexatriene

Question

Quizplus · Accepted Answer

The compound with the longest conjugated system will absorb light at the longest wavelength. (E)-1,3,5-hexatriene has the longest conjugated system out of all the options, so it will absorb light at the longest wavelength.

Which of the Following Compounds Absorbs the Longest Wavelength of UV-Visible