Question

Both s-cis and s-trans conformers of 1,3-butadiene have a continuous conjugated π system, which of the following statements is true about the s-cis conformer?

The s-cis conformer is lower in energy than the s-trans conformer
The s-cis conformer is higher in energy than the s-trans conformer.
The s-cis conformer has equal energy as the s-trans conformer.
None of these.

Answer 1

second option (B)

Step-by-step explanation:

The s-cis conformer is higher in energy than the s-trans conformer. The most stable conformer has bent-inward geometry which favors the π bond interaction with methyl/methylene hydrogen/carbon atom hence more crowding with consequent higher energy, this is also responsible for the higher boiling point of the s-cis conformer.