Question

Statement 1: $ 2,3$-dimethyl but-$2$-ene is more stable than but-$2$-ene.
Statement 2: $2,3$-dimethyl but-$2$-ene possesses $12 \alpha$-hydrogen atoms whereas but-$2$-ene possesses only $6 \,\alpha$-hydrogen atoms and therefore former shows more pronounced hyperconjugation.

• A. If both Statement $1$ and Statement $2$ are true and the statement $2$ is the correct explanation of the statement $1$
• B. If both Statement $1$ and Statement $2$ are true but statement $2$ is not the correct explanation of the statement $1$
• C. If Statement $1$ is true but Statement $2$ is false
• D. If Statement $1$ is false but Statement $2$ is true

Answer 1

Answer: (A)

The phenomenon of displacement of electrons by conjugative mechanism involving $\sigma$- and $\pi$-electron is called hyperconjugation. It happens when alkyl groups having at least one of the $\alpha$-carbon atoms attached to an unsaturated carbon atom is able to release electrons due to delocalization of $\sigma$- and $\pi$-bond. It is more pronounced as $\alpha-H$ atoms are more in number. Thus, stability of alkenes has been explained in terms of hyperconjugation.