Answer: Cyclobutadiene.
- A Benzene
- B Cyclobutadiene
- C Cyclopropenyl cation
- D Naphthalene
Correct answer: B. Cyclobutadiene
Explanation: Cyclobutadiene contains 4 pi electrons and is antiaromatic.
Geometric (cis-trans) isomers of 1,2-dichloroethene differ only in the relative arrangement of groups across the rigid C=C double bond.
Concept context
General Organic Chemistry covers the rules behind all organic reactions. Covers inductive effect, resonance, hyperconjugation, types of reactions (substitution, addition, elimination), and isomerism including optical and geometric forms.
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