Question

The hyperconjugative stabilities of tert-butylcation and 2-butene, respectively are due to:

• A. $\sigma -$ p(empty) and $\sigma -{\pi }^{\ast }$ electron delocalizations
• B. $\sigma \to {\sigma }^{\ast }$ and $\sigma \to \pi$ electron delocalizations
• C. $\sigma \to p$ (filled) and $\sigma \to \pi$ electron delocalizations
• D. p (filled) $\to {\sigma }^{\ast }$ and $\sigma \to {\pi }^{\ast }$ electron delocalizations

Answer 1

The correct option is A $\sigma -$ p(empty) and $\sigma -{\pi }^{\ast }$ electron delocalizations

Hyperconjugation in carbocation is the delocalisation of sigma bond to the empty $\pi$ orbital of the carbocation.
Hyperconjugation in alkene is the delocalisation of sigma bond to the ${\pi }^{\ast }$ orbital of the double bond.