Explain the change in color observed in arylamines like aniline upon storage and the reason behind it.

Arylamines like aniline often undergo discoloration upon exposure to air and light during storage. This color change, from a colorless or pale yellow to a darker color, is attributed to the oxidation of the amine. Aniline is particularly susceptible to air oxidation, forming colored products such as azobenzene derivatives. This reaction involves the formation of highly conjugated systems, leading to the observed color change. To prevent this discoloration, arylamines are often stored in dark containers or under inert gas to minimize exposure to oxygen and light, preserving their original color and chemical integrity.