Question

Assertion `:` `2,3-`dimethyl but`-2-`ene is more stable than but`-2-`ene.
Reason `:` `2,3-`dimethyl but`-2-` ene possesses `12 alpha-` hydrogen atoms whereas but `-2-`ene possesses only `6 alph-`hydrogen atms and therefore former shows more pronounced hyperconjugation.
A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Answer 1

Correct 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 electron due to delocalization of `sigma-` and `pi-` bond. It is more pronounced as `alph-H` atoms are more in number . Thus, stability of alkenes has been explained in terms of hyperconjugation.