MCQs – Electrophilic Reactions (20 Practice Questions)
Q1. Electrophilic addition is generally observed in?
Answer: A. Electrophilic addition is typical for π-bond containing compounds like alkenes and alkynes.
Q2. In the first step of electrophilic addition, the electrophile attacks?
Answer: A. The electrophile attacks the electron-rich π-bond to form a carbocation intermediate.
Q3. Which is a common example of electrophilic substitution reaction?
Answer: A. Nitration, halogenation, sulphonation of benzene are classic electrophilic substitution reactions.
Q4. In Markovnikov’s rule, the electrophile attaches to the carbon having?
Answer: A. According to Markovnikov’s rule, the electrophile attaches to the carbon with more hydrogens, stabilizing the carbocation.
Q5. Anti-Markovnikov addition occurs in the presence of?
Answer: B. Peroxides cause free-radical mechanism leading to anti-Markovnikov addition (Kharasch effect).
Q6. Which intermediate is formed in most electrophilic addition reactions?
Answer: A. Carbocations are key intermediates in electrophilic addition.
Q7. Which of the following is an electrophile?
Answer: A. H⁺ ion is electron-deficient and acts as an electrophile.
Q8. Which reaction is an example of electrophilic substitution?
Answer: A. Bromination of benzene involves electrophilic substitution.
Q9. Which of the following stabilizes a carbocation formed in electrophilic addition?
Answer: A. Hyperconjugation stabilizes carbocations.
Q10. In the nitration of benzene, the attacking electrophile is?
Answer: A. The nitronium ion (NO₂⁺) is the actual electrophile.
Q11. Which condition favors electrophilic aromatic substitution?
Answer: A. Electron donating groups activate the benzene ring.
Q12. Which is NOT an electrophilic substitution reaction?
Answer: C. Aldol condensation is nucleophilic in nature.
Q13. The catalyst used in Friedel-Crafts alkylation is?
Answer: A. AlCl₃ is used as a Lewis acid catalyst.
Q14. Which species attacks in the sulphonation of benzene?
Answer: A. SO₃ acts as the electrophile.
Q15. Electrophilic addition to alkynes gives mostly?
Answer: A. Alkynes react with electrophiles giving vinyl carbocations.
Q16. In halogenation of benzene, the role of FeCl₃ is?
Answer: A. FeCl₃ helps generate Cl⁺ electrophile.
Q17. Which intermediate is common in EAS reactions?
Answer: A. Arenium ion (sigma complex) is the intermediate.
Q18. Which of the following is an electron donating group in benzene?
Answer: A. -OH donates electron by resonance, activating the ring.
Q19. Which of the following undergoes electrophilic substitution fastest?
Answer: A. Phenol is highly activated towards EAS due to -OH group.
Q20. Which directing group is meta-directing in EAS?
Answer: A. -NO₂ is electron-withdrawing and meta-directing.
