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Revisions

Organic Reaction Mechanisms

Grade

13

Level 1 — Basic Recall (1–10)

  1. What is a reaction mechanism?

  2. Define a nucleophile.

  3. Define an electrophile.

  4. What is an intermediate?

  5. Name the mechanism: CH₃Br + OH⁻ → CH₃OH + Br⁻.

  6. Name the mechanism: CH₂=CH₂ + HBr → CH₃–CH₂Br.

  7. What is a carbocation?

  8. What is a free radical?

  9. Define homolytic fission.

  10. Define heterolytic fission.



Level 2 — Understanding (11–20)

  1. Explain why SN2 reactions are concerted.

  2. Why do SN1 reactions form carbocations?

  3. Why are tertiary halides more likely to undergo SN1?

  4. Why do primary halides favour SN2 mechanisms?

  5. Describe Markovnikov’s rule.

  6. What is the role of catalysts in electrophilic aromatic substitution?

  7. Why do alkenes undergo electrophilic addition?

  8. Explain why benzene undergoes substitution instead of addition.

  9. What is meant by stereospecificity in SN2 reactions?

  10. Compare E1 and E2 eliminations.



Level 3 — Application (21–30)

  1. Predict whether bromoethane reacts with OH⁻ via SN1 or SN2.

  2. Draw the mechanism for SN2 reaction of CH₃Br with OH⁻.

  3. Identify the intermediate in an E1 elimination reaction.

  4. Predict the major product for 2-bromopropane + alcoholic KOH.

  5. Explain why addition of HBr to propene gives 2-bromopropane (Markovnikov).

  6. Predict the product of electrophilic addition of Br₂ to ethene.

  7. Explain why phenol undergoes substitution more readily than benzene.

  8. Predict the product(s) for nitration of toluene.

  9. Identify the type of mechanism in the chlorination of methane.

  10. Predict the major elimination product using Zaitsev’s rule.



Level 4 — Analysis (31–40)

  1. Analyse why SN1 reactions give racemic mixtures.

  2. Explain the effect of bulky nucleophiles on SN2 reactions.

  3. Compare the energy profiles of SN1 and SN2 reactions.

  4. Analyse how the stability of carbocations affects reaction pathways.

  5. Explain regioselectivity in Markovnikov vs anti-Markovnikov addition.

  6. Discuss why E2 mechanisms require a strong base.

  7. Predict the influence of solvent polarity on SN1 vs SN2.

  8. Analyse electrophilic substitution directing groups (activating vs deactivating).

  9. Explain why halogens are deactivating but ortho/para-directing.

  10. Compare radical stability using hyperconjugation and resonance.



Level 5 — Exam/Challenge (41–50)

  1. Provide a complete mechanism for hydration of ethene using acid catalysis.

  2. Predict the product distribution for addition of HBr to 1,3-butadiene (1,2- vs 1,4-addition).

  3. Explain energy profiles for E1 vs E2, identifying all intermediates.

  4. Evaluate stereochemical outcomes of SN2 reactions using Newman projections.

  5. Predict products of an electrophilic aromatic substitution with meta-directing groups.

  6. Compare stability of carbocations using resonance (e.g., benzyl vs allyl vs tert-C⁺).

  7. Provide mechanistic explanation for formation of rearranged products in carbocation reactions.

  8. Explain orbital interactions in pericyclic reactions (if in syllabus; otherwise qualitative).

  9. Derive the Hammond postulate and apply it to SN1 or electrophilic addition transition states.

  10. Analyse the mechanism of free radical polymerization (initiation, propagation, termination).

වියාචනය (Disclaimer)

Idasara Academy ඉගෙනුම් සම්පත් නිර්මාණය කර ඇත්තේ සිසුන්ට මගපෙන්වීම, පුහුණුව සහ අධ්‍යයන උපායමාර්ග ලබාදී සහයෝගය දැක්වීමටය.

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ජාතික විභාග සඳහා අන්තර්ගතයේ නිල බලය ලත් මූලාශ්‍රය වනුයේ රජය විසින් නිකුත් කරනු ලබන මෙම ප්‍රකාශනයි.

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