Organic chemistry is one of the most challenging subjects for college and university students, especially if you are preparing for medical or STEM careers. In fact, studies show that over 58% of students rate organic chemistry as their most difficult science course.
If you have ever felt overwhelmed by complex mechanisms, multi-step synthesis routes, or endless reaction lists, you are not alone.
Success in organic chemistry does not come from memorizing reactions. It comes from active practice by solving exam-style problems, understanding step-by-step solutions, and gaining confidence with every topic.
This post brings you must-know organic chemistry practice problems, including synthesis, mechanisms, and reactions, along with detailed answers.
By practicing these problems and reviewing the solutions, you will be well on your way to mastering organic chemistry for your exams.
Why Practice Tests Matter in Organic Chemistry
Many students approach organic chemistry by simply reading textbooks or rewatching lectures. Yet, true progress comes when you put your understanding to the test with real problems.
Active learning by using practice tests can help you build confidence and decode complex material into understandable and applicable content.
Here is why practice problems are so important:
- Train your brain: You start to spot patterns, anticipate exam questions, and work through tricky mechanisms.
- Identify weak spots: Practice reveals which concepts need more review so you can focus where it counts.
- Develop critical thinking: Solving different types of questions helps you think like a chemist, not just memorize facts.
- Build exam skills: The more you practice, the faster and more accurate answers you can attempt on test day.
Top Practice Questions with Answers
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Synthesis Problems in Organic Chemistry
Tackling organic chemistry synthesis problems is crucial for exams. Below are key organic chemistry synthesis practice problems that reflect the kinds of questions you will see:
- Convert benzene to p-bromoaniline using any required reagents.
- Outline a synthesis of 2-butanol starting from ethyne (acetylene).
- Devise a multi-step synthesis for converting cyclohexene to cyclohexanone.
- Propose a synthesis for phenol from chlorobenzene.
- Which of the following is a synthesis reaction?
- A. Ethene + Br₂ → 1,2-dibromoethane
- B. 1-butanol → 1-butanal
- C. 2-bromopropane + NaOH → propan-2-ol
- D. Benzene + HNO₃ → Nitrobenzene
- Synthesize ethyl acetate starting from ethanol and acetic acid.
- Suggest a method to prepare tert-butyl alcohol from isobutylene.
- Prepare acetophenone from benzene in two steps.
- How would you synthesize aniline from nitrobenzene?
- Synthesize methyl tert-butyl ether (MTBE) from methanol and isobutylene.
Answer Key:
| No. | Question Summary | Answer |
| 1 | Benzene to p-bromoaniline | Benzene → bromobenzene (Br₂/FeBr₃), then nitration, reduction, bromination, diazotization, and reduction to p-bromoaniline.
1. NaNH₂, EtBr 2. NaNH₂, MeBr 3. H₂O/H₂SO₄, HgSO₄ 4. NaBH₄ Ethyne ────────────────► 1-Butyne ──────────────► 2-Butyne ──────────────► 2-Butanone ──────────► 2-Butanol (Alkylation) (Alkylation) (Hydration) (Reduction) |
| 2 | Ethyne to 2-butanol | Ethyne → 2-butyne (alkylation), then hydration to 2-butanol. |
| 3 | Cyclohexene to cyclohexanone | Cyclohexene → cyclohexanol (epoxidation + hydrolysis), then oxidation to cyclohexanone. |
| 4 | Chlorobenzene to phenol | Chlorobenzene (NaOH, high temp/pressure), then acid workup to yield phenol. |
| 5 | Synthesis reaction identification | A (Ethene + Br₂ → 1,2-dibromoethane), D (Benzene + HNO₃ → Nitrobenzene) are synthesis reactions. |
| 6 | Ethanol + acetic acid → ethyl acetate | Ethanol + acetic acid (H₂SO₄ catalyst) → ethyl acetate (Fischer esterification). |
| 7 | Isobutylene to tert-butyl alcohol | Isobutylene + water (acid catalyst) → tert-butyl alcohol. |
| 8 | Benzene to acetophenone (2 steps) | Benzene → acetophenone via Friedel–Crafts acylation (acetyl chloride/AlCl₃). |
| 9 | Nitrobenzene to aniline | Nitrobenzene (Sn/HCl or Fe/HCl reduction) → aniline. |
| 10 | Methanol + isobutylene → MTBE | Methanol + isobutylene (acid catalyst) → methyl tert-butyl ether (MTBE). |
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Mechanisms in Organic Chemistry
Understanding mechanisms is the backbone of organic chemistry. Here are essential organic chemistry mechanisms practice questions to sharpen your skills:
- Draw the complete mechanism for the addition of HBr to propene (show intermediates).
- Show the SN2 mechanism for the reaction of 1-bromopropane with NaCN.
- Provide the E2 elimination mechanism for 2-bromobutane with sodium ethoxide.
- Outline the steps of the aldol condensation between acetaldehyde molecules.
- Write the stepwise mechanism for the acid-catalyzed hydration of ethene.
- Show the nucleophilic aromatic substitution (SNAr) mechanism for chlorobenzene with NaOH.
- Draw the full mechanism for the Fischer esterification of acetic acid with ethanol.
- Illustrate the steps in the bromination of benzene (electrophilic aromatic substitution).
- Detail the mechanism for the hydroboration-oxidation of 1-hexene.
- Explain the Claisen rearrangement mechanism for allyl phenyl ether.
Answer Key:
| No. | Question Summary | Answer |
| 1 | HBr addition to propene | Markovnikov addition via carbocation intermediate. |
| 2 | SN2: 1-bromopropane with NaCN | Backside attack (inversion of configuration). |
| 3 | E2: 2-bromobutane with NaOEt | Anti-periplanar elimination forms alkene (double bond). |
| 4 | Aldol condensation (acetaldehyde) | Enolate formation, nucleophilic addition, dehydration. |
| 5 | Acid-catalyzed hydration of ethene | Protonation, carbocation, nucleophilic attack by water, deprotonation. |
| 6 | SNAr: chlorobenzene with NaOH | Addition-elimination on aromatic ring (benzyne intermediate). |
| 7 | Fischer esterification (acetic acid + ethanol) | Acid catalysis, nucleophilic attack, loss of water, ester formation. |
| 8 | Bromination of benzene | Electrophilic aromatic substitution: benzene attacks Br⁺, forms sigma complex, then rearomatization. |
| 9 | Hydroboration-oxidation of 1-hexene | Syn addition of borane, followed by oxidation (H₂O₂/NaOH) to alcohol. |
| 10 | Claisen rearrangement of allyl phenyl ether | [3,3]-sigmatropic rearrangement, migration of allyl group. |
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Reactions in Organic Chemistry
Exam success often depends on your reaction prediction skills. Practice these organic chemistry reactions practice questions:
- Predict the product for the reaction of 2-methyl-2-butene with Br₂ in CCl₄.
- What is the major product of cyclohexene with cold KMnO₄?
- Give the product(s) for benzaldehyde reacting with LiAlH₄.
- What is the outcome of reacting 1-butyne with excess HBr?
- What forms when methyl bromide is treated with magnesium in dry ether?
- Predict the product of phenol with Br₂ (water).
- What is produced when toluene is oxidized with KMnO₄?
- What is the product when ethyl acetoacetate is hydrolyzed and heated?
- What product forms from the ozonolysis of 1-butene?
- What do you obtain when propene is reacted with OsO₄?
Answer Key:
| No. | Question Summary | Answer |
| 1 | 2-methyl-2-butene + Br₂ in CCl₄ | 2,3-dibromo-2-methylbutane. |
| 2 | Cyclohexene + cold KMnO₄ | cis-1,2-cyclohexanediol. |
| 3 | Benzaldehyde + LiAlH₄ | Benzyl alcohol. |
| 4 | 1-butyne + excess HBr | 2,2-dibromobutane. |
| 5 | Methyl bromide + Mg (dry ether) | Methyl magnesium bromide (Grignard reagent). |
| 6 | Phenol + Br₂ (water) | 2,4,6-tribromophenol. |
| 7 | Toluene + KMnO₄ | Benzoic acid. |
| 8 | Ethyl acetoacetate (hydrolyzed, heated) | Acetic acid. |
| 9 | Ozonolysis of 1-butene | Butanal and formaldehyde. |
| 10 | Propene + OsO₄ | Propane-1,2-diol (syn diol). |
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Conclusion
Mastering organic chemistry demands real understanding, practice, and the confidence to tackle any exam question. When you work through targeted organic chemistry practice problems, you start building real exam skills.
By challenging yourself with synthesis, mechanisms, and reaction-based questions, you get ready for every scenario you might see on test day.
Orango’s clarity-driven approach, complete with step-by-step solutions and tutor support, transforms your study time into meaningful progress.
Choose the smart path to success—make practice a habit, use quality resources, and let Orango guide you toward mastery in organic chemistry.
