CBSE Class 12-science Answered
Dear Student,
Carbocations always constitute a intermediate stage.If a carbocation is more stable then other then probability of formation of that carbocation will be more in comparision to unstable carbocation.Thus probability of reaction taking the path which involves formation of that carbocation will be very high .
Now consider a separate scenario.Consider that somehow the carbocations have been made.In this case obviously unstable carbocation will react faster to acheive a stable state.
So for the whole reaction one is faster which involves formation of stable carbocation(usually always) but sometimes the case may be opposite depending on the free energy value of reaction.