Question

Several factors can affect alkene stability. Explain why alkene A is more stable than alkene B even though both contain disubstituted carbon-carbon double bonds.

Short answer

Alkene A is more stable since the double bond is present in a 6-membered ring where the alkene suffers less angular strain.

Step-by-step solution

Alkene

Alkene is one of the unsaturated hydrocarbons in which double bonds are present. The general formula to represent alkenes is ${\mathbf{\text{C}}}_{\mathbf{\text{n}}}{\mathbf{\text{H}}}_{\mathbf{\text{2n}}}$.

Where n is the carbon count.

Classification based on substitution

Both the structures are disubstituted and are marked as black, but the double bond is marked as blue.

Representation of the substituents across the double bond

Stability based on angle strain

Angle strain is caused when the bond angles deviate from their ideal value. The observed strain energy is found to be much higher in a four-membered ring as compared to a six-membered ring.

Hence, alkene A is more stable since the double bond is present in a six-membered ring where the alkene suffers less angular strain.