Question

Why are trans alkenes more stable than cis alkenes?

Answer 1

Hint: Alkenes are unsaturated hydrocarbons consisting of one or more double bonded carbon atoms. The alkenes can exist two different stereo isomers which are known as cis isomer and trans isomer. Trans isomers have the same groups attached to the opposite side of the double bond which will have less steric hinderance compared to cis isomer.

Complete answer:
The compounds with the same molecular formula but different structure or arrangements are known as isomers and the phenomenon is known as isomerism.
The compounds with the same molecular formula but different arrangement are known as stereoisomers. Geometrical isomerism is the subcategory of stereoisomerism. Geometrical isomerism is given by cis and trans isomers.
Cis isomer is the compound with same groups attached on one side of double bond or triple bond. Trans isomer is the compound with same groups attached on the opposite side of double bond or triple bond.
Alkenes exhibit cis and trans isomerism in which trans isomerism has same groups on opposite side leads to less steric hinderance. The compounds with less steric hindrance are more stable. Whereas cis alkenes have less high steric hinderance. Thus, trans alkenes are more stable than cis alkenes.

Note:
Not only alkenes, alkynes and cycloalkenes exhibit cis and trans isomerism. Trans alkenes are thermodynamically more stable than cis alkenes due to the less steric hinderance only. E and z nomenclature can be written to alkenes when alkenes contain four different groups.