Question

Explain why `(CH_3)_3C^(oplus)` is more stable than `CH_3 overset (oplus) C H_2` and `overset (oplus) C H_3` is less stable.

Answer 1

Hyperconjugation interaction in `(CH_3)_3 C^(oplus) (I)` is greater than that of `C` in `CH_3 overset (oplus) CH_2 (II)`, as `(I)` has nine `(C - H)` bonds and `(II)` has three `(C - H)` bonds.
In `overset (oplus) CH_3`, the vacant `p` orbital is perpendicular to the plane in which `(C- H)` bonds lies , hence cannot overlap with it.
Thus, `overset (oplus) CH_3` lacks hyperconjugative stability.