Question

The higher stabilities of tert-butyl cation over isopropyl cation and trans-2- butene over propene, respectively, are due to orbital interactions involving

• A. $\sigma \to \pi$ and $\sigma \to {\pi }^{\ast }$
• B. $\sigma \to$ vacant $p$ and $\sigma \to \pi$
• C. $\sigma \to {\sigma }^{\ast }$ and $\sigma \to \pi$
• D. $\sigma \to$ vacant $p$ and $\sigma \to {\pi }^{\ast }$

Answer 1

Answer: (D)

Tert-butyl cation is more stable than isopropyl cation, because of better hyper conjugation between a-vacant and p-orbital.

whereas, trans-2-butene is more stable than propene because of hyper conjugation $\sigma -\pi$ * -orbitals.