The electrophile E+ attacks the benzene ring to generate the intermediate σ-complex. Of the following, which σ-complex is of lowest energy?
The treatment of CH3MgX with CH3C ≡ C — H produces
CH3 — CH ≡ CH2
CH3 — C ≡ C —CH3
CH4
Which cycloalkane has the lowest heat of combustion per CH2 group?
