# Carbocation

• Ans: a
Why opt a is the answer? Why not b? What is the meaning of half life of carbocation?

• @anag
The lifetime of a carbocation is nothing but the reciprocal of the rate coefficient (ks) for its disappearance in a given solvent, possibly by solvation.
I'm guessing half life is when half concentration of the carbocations disappear.

As for the answer, all options given are 3° so we gotta check which of the compounds attached are very stable.
A is a 3° cation in attachment with CMC. Very stable. Second only to benzylic carbocation, but since we don't have bezylic, we consider it most stabel as of yet.
B is benzylic attached to only one.
C is 3° cation in attachment to cyclohexane.
D is 3° cation

@anag
The lifetime of a carbocation is nothing but the reciprocal of the rate coefficient (ks) for its disappearance in a given solvent, possibly by solvation.
I'm guessing half life is when half concentration of the carbocations disappear.

As for the answer, all options given are 3° so we gotta check which of the compounds attached are very stable.
A is a 3° cation in attachment with CMC. Very stable. Second only to benzylic carbocation, but since we don't have bezylic, we consider it most stabel as of yet.
B is benzylic attached to only one.
C is 3° cation in attachment to cyclohexane.
D is 3° cation

Here all options are not 3° since opt b (benzylic carbocation). Why can't option b be the answer?

What is the meaning of CMC? Why is a 3-membered ring (opt a) more stable than a 6-membered ring (opt c) ? Please explain.

• @anag Here all options are not 3° since opt b (benzylic carbocation).

What is the meaning of CMC? Please explain.

Why is a 3-membered ring (opt a) more stable than a 6-membered ring (opt c) ?

Does it mean that dancing resonance is more stable than ordinary resonance? Please explain.

• @pranay-singh here there is no carbanion in the options. Only carbocation is present.

Can you please explain the doubts written above?