Why does benzene undergo electrophilic aromatic substitution rather than electrophilic addition across its double bonds?
Answer and explanation
Correct answer: D. Substitution preserves the exceptionally high resonance stabilization energy of the aromatic ring
Benzene has ~150 kJ/mol of resonance energy. Addition would permanently destroy the cyclic conjugated aromatic sextet. Substitution restores the aromatic ring in the second step (deprotonation of arenium ion), preserving resonance stabilization.
Practise more Hydrocarbons and Functional Groups.
Free questions with an explanation for every one, and full timed Medical University Entrance Examination (Bulgaria) mock tests.
More Hydrocarbons and Functional Groups questions
- What is the IUPAC name of the branched alkane with structural formula (CH3)2CH-CH2-CH(CH3)2?
- What type of isomerism is demonstrated by butane and 2-methylpropane (isobutane)?
- What is the most stable conformation of cyclohexane at room temperature due to minimized torsional and steric strain?
- Which step in the free-radical chlorination of methane generates chlorine radicals by homolytic cleavage of Cl2?
- According to Markovnikov's rule, what major product is formed when propene reacts with hydrogen bromide (HBr)?
- Why does addition of hydrogen bromide to propene in the presence of benzoyl peroxide yield 1-bromopropane as the major product?