For which class of compounds does the lack of free rotation around carbon-carbon bonds result in the existence of cis-trans isomerism?

Question

Quizplus · Accepted Answer

The lack of free rotation around carbon-carbon double bonds in alkenes leads to the existence of cis-trans isomerism. In the cis form, the two largest substituents are on the same side of the double bond, while in the trans form, they are on opposite sides. Alkanes, alkynes, and arenes do not have double bonds and therefore have free rotation around carbon-carbon bonds.

For Which Class of Compounds Does the Lack of Free