Question

Question #bc002

Answer 1

Carboanions are generally stabilized via resonance (and other factors that stabilize negative charges, such as induction) and carbocations are generally stabilized via hyperconjugation.

In the former case consider,

Toluene has far less resonance than the other molecule when deprotonated. Thus, the second molecule is probably far more stable with the negative charge.

In the latter case consider,

The positive charge is stabilized as a function of adjacent `C-H` bonds inductively donating electron density to the resultant empty p-orbital on the carbocation.

Three, two, and one `C-H` bonds donate electron density above. Hence, these are called tertiary, secondary, and primary carbocations, respectively.

This is also demonstrated in radicals.