Rotation about the C=C bond in trans-but-2-ene (CH₃CH=CHCH₃) is restricted primarily…
CHEMISTRY · Single correct · A Level · Chemistry · Alkenes · Alkenes
Problem
Rotation about the C=C bond in trans-but-2-ene (CH₃CH=CHCH₃) is restricted primarily for which reason?
(a) Rotation would force the two methyl groups into an eclipsed conformation, and the resulting steric/torsional strain locks the bond.
(b) Breaking the π component of the C=C double bond would be required, which demands significantly more energy than torsional strain.
(c) Hyperconjugation between the methyl groups and the double bond delocalizes electrons and freezes the bond.
(d) The σ component of the C=C double bond is oriented side-on between p orbitals, so it cannot rotate freely.