How many s bond orbitals are available for overlap with the vacant p orbital in the methyl cation? b. which is more stable: a methyl cation or an ethyl cation? why? problem 3 ♦ a. how many s bond orbitals are available for overlap with the vacant p orbital in 1. the isobutyl cation? 2. the n-butyl cation? 3. the sec-butyl cation? b. which of the carbocations in part a is most stable? problem 4 ♦ rank the following carbocations in each set from most stable to least stable: