Answer:
A conjugated system can solely consist of two alkenes: Incorrect
B. A cumulated diene is not as stable as an isolated diene.
Incorrect
Explanation:
A. A conjugated system has greater stability compared to an unconjugated system.: Correct
Owing to resonance, a conjugated system exhibits increased stability.
B. The s-trans form is preferred over the s-cis form.: Correct
Because of repulsion in the s-cis form, they are less stable.
C. A conjugated system has multiple resonance forms.Correct
This contributes to their stability.
D. A conjugated system can only comprise two alkenes: Incorrect
A conjugated system may consist of alternating double and triple bonds.
2) A trans alkene liberates less heat during hydrogenation compared to a cis alkene.
Correct
Trans alkenes are more stable than their cis counterparts, resulting in a lower heat of hydrogenation for trans alkenes.
B. A cumulated diene is less stable than an isolated diene.
Incorrect
C. Numerous products can potentially form when a conjugated diene reacts with HBr. Correct
This can result in either 1,2 or 1,4 addition.
D. Conjugated systems occur only between sp2-hybridized atoms.
Correct
Conjugation enables resonance, which is feasible in sp2 systems.
E. Conjugated double bonds rely on unhybridized p-orbitals that align with one another.
Correct
The double bond forms as a pi bond due to the lateral overlap of unhybridized p orbitals.
