04-BS-12
Worked solutions to 14 past sittings (2013–2019), 134 questions. Pick a sitting, or start from a topic below.
- December 2019
- December 2018
- May 2018
- December 2017
- May 2017
- December 2016
- May 2016
- December 2015
- May 2015
- December 2014
- May 2014
- December 2013
- May 2013
- Undated paper
Topics across the sittings
Topics that come up in more than one sitting, taken from the headings of our worked solutions. A topic counts once per sitting.
- Carbon Classification (4 sittings): December 2015 Q5 · December 2014 Q4 · May 2014 Q1 · December 2013 Q1
- Acidity (3 sittings): December 2019 Q12 · May 2018 Q12 · May 2017 Q1
- Alkene Stability (3 sittings): May 2015 Q3 · May 2014 Q4 · May 2013 Q4
- Cocaine (3 sittings): December 2019 Q1 · December 2018 Q1 · May 2018 Q1
- Mass Spectrometry (3 sittings): December 2019 Q10 · December 2018 Q13 · May 2018 Q10
- NMR Structure Elucidation (3 sittings): December 2019 Q10 · December 2018 Q13 · May 2018 Q10
- Stereochemistry (3 sittings): December 2018 Q10 · December 2017 Q4 · December 2016 Q4
- Alkane/Haloalkane Nomenclature (2 sittings): December 2015 Q2 · December 2014 Q2
- Anti-Markovnikov HBr Addition (2 sittings): December 2017 Q10 · December 2016 Q10
- Antioxidant Activity (2 sittings): December 2019 Q12 · May 2018 Q12
- Arene Oxide (2 sittings): December 2019 Q3 · May 2018 Q3
- Ascorbate Radical (2 sittings): December 2018 Q9 · May 2017 Q11
- Benzene Metabolism (2 sittings): December 2019 Q3 · May 2018 Q3
- Cocaine Hydrochloride (2 sittings): December 2019 Q1 · May 2018 Q1
- Colour (2 sittings): December 2019 Q12 · May 2018 Q12
Questions by sitting
December 2019
- Question 1: Cocaine vs. Cocaine Hydrochloride
- Question 2: Cholic Acid and Bile Salt Amphiphilicity
- Question 3: Benzene Metabolism — Arene Oxide and Phenol
- Question 4: Stereochemistry of the Dimethylcyclopropanes
- Question 5: Reaction-Energy Diagrams
- Question 6: Intermolecular vs. Intramolecular Esterification Equilibrium
- Question 7: S N 2 Stereochemistry at a Single Stereocentre
- Question 8: Propranolol Total Synthesis
- Question 9: Five Syntheses from Cyclohexene
- Question 10: Mass Spectrometry, IR, and NMR Structure Elucidation
- Question 11: Addition Polymer Monomers
- Question 12: Curcumin Tautomerism, Acidity, Colour, and Antioxidant Activity
- Question 13: Step-Growth Polymers — Polyesters and Polyamides
December 2018
- Question 1: Acid–Base Sites in Ibuprofen and Cocaine
- Question 2: S N 1 vs. S N 2 — Four Substitution Reactions
- Question 3: Two Routes to Each Ether
- Question 4: Stereochemistry of Substitution Products
- Question 5: Cholic Acid → Bile Salt Amphiphilicity
- Question 6: Propranolol Synthesis
- Question 7: Melting Points of Elaidic, Oleic, and Stearic Acids
- Question 8: Reagents for the Cyclopentene Reaction Web
- Question 9: The Ascorbate (Vitamin C) Radical
- Question 10: Diels–Alder Products and Stereochemistry
- Question 11: Brevicomin — Structure and Synthesis
- Question 12: Arene Oxide Metabolism
- Question 13: Mass Spectrometry, IR, and NMR Structure Elucidation
May 2018
- Question 1: Cocaine vs. Cocaine Hydrochloride — Boiling Point and Solubility
- Question 2: Cholic Acid → Bile Salt — Amphiphilic Lipid Transport
- Question 3: Benzene Metabolism — Arene Oxide and Phenol
- Question 4: Four Isomeric Dimethylcyclopropanes — Isomerism, Chirality, Physical Properties
- Question 5: Reaction-Energy Diagrams
- Question 6: Intermolecular vs. Intramolecular Esterification — Why K eq Differs
- Question 7: Stereochemistry Across Three Reaction Branches from One Alcohol
- Question 8: Stepwise Synthesis of Propranolol
- Question 9: Five Syntheses from Cyclohexene
- Question 10: Mass Spectrometry, IR, and NMR Structure Elucidation
- Question 11: Polymer Monomer Identification
- Question 12: Curcumin — Keto–Enol Tautomerism, Acidity, Colour, Antioxidant Activity
- Question 13: Polyester/Polyamide Monomer–Polymer Identification
December 2017
- Question 1: Bronsted–Lowry Acidity/Basicity of Drug Molecules
- Question 2: Pharmacokinetics — THC vs. Ethanol Detection Windows
- Question 3: Penicillin G — Differential Amide Reactivity
- Question 4: S N 2 Reactions — Products and Stereochemistry
- Question 5: Stepwise Synthesis of Propranolol
- Question 6: Retrosynthesis — Acetylide + Alkyl Halide
- Question 7: Synthesis from Acetylene (≤C 2 Fragments)
- Question 8: IR Spectrum Matching
- Question 9: Structure Elucidation from MS/IR/NMR
- Question 10: Markovnikov vs. Anti-Markovnikov HBr Addition
- Question 11: Synthesis from Benzene (Seven Targets)
- Question 12: Explaining Relative Acidities (pK a )
- Question 13: Poly(ester amide) Monomer Identification
May 2017
- Question 1: Acidity — Ether vs. Alcohol; Doubly-Allylic vs. Ordinary C–H
- Question 2: Nonionic (Neutral) Surfactants — How They Clean Without a Charge
- Question 3: Penicillin G — Why the β-Lactam Amide Is the Reactive One
- Question 4: Amygdalin & Mandelic Acid — Stereocentres, Enantiomers, Optical Rotation
- Question 5: Propranolol — Two Successive Nucleophilic Substitutions
- Question 6: Intramolecular vs. Intermolecular Esterification — Why K eq Differs
- Question 7: Mechanisms (S N 1 Solvolysis; Exhaustive Methylation) & a Slow-Reacting Hexachlorocyclohexane
- Question 8: Halohydrin → Epoxide Ring Closure — Conformational Control
- Question 9: Matching Six Compounds to Their IR Spectra
- Question 10: Identifying Two Esters from Formula + 1 H NMR
- Question 11: Vitamin C — Ascorbate Radical and Why That H Is So Easily Removed
- Question 12: Seven Multi-Step Syntheses from Benzene
- Question 13: Identifying the Four Monomers of a Poly(ester amide)
December 2016
- Question 1: Acid/Base Sites in Drug Molecules
- Question 2: Pharmacokinetics: Lipophilic vs. Water-Soluble Drugs
- Question 3: Differential Amide Reactivity in Penicillin G
- Question 4: S N 2 Products and Stereochemistry
- Question 5: Two-Step Nucleophilic Synthesis of Propranolol
- Question 6: Retrosynthesis of Internal Alkynes via Acetylide Alkylation
- Question 7: Multi-Step Synthesis from Acetylene (≤2-Carbon Building Blocks)
- Question 8: IR-Spectrum Matching for Six Isomeric/Related C–H, O, and Functional Classes
- Question 9: Structure Elucidation: Regiochemistry of Ketone Enolate Alkylation
- Question 10: Markovnikov vs. Anti-Markovnikov HBr Addition: Rearrangement vs. Radical Mechanism
- Question 11: Multi-Step Aromatic Synthesis Design from Benzene
- Question 12: Substituent Effects on Phenol and Carboxylic Acid Acidity
- Question 13: Identifying the Four Monomers of a Poly(ester amide) Drug-Delivery Copolymer
May 2016
- Question 1: Structure Elucidation from IR/ 13 C NMR (C 4 H 6 O 2 )
- Question 2: Cysteine — pK a Assignment and Ionisation States
- Question 3: Two Routes to an Amino Alcohol — Which Succeeds?
- Question 4: Doxazosin Synthesis — Reagents and Rationale
- Question 5: Solvent Effects on Three Reactions (Hughes–Ingold Rules)
- Question 6: Diastereomers of a Trisubstituted Cyclopentane
- Question 7: S N 1 or S N 2? Four Cases
- Question 8: Chair or Boat — Six Bridged/Caged Systems
- Question 9: Position of the Double Bond After Dehydration/Hydrolysis — Enantiopurity
- Question 10: Acid-Catalysed α-Bromination of a Ketone
- Question 11: Total Synthesis of Proparacaine
- Question 12: Why 2-/4-Chloropyridine React with Nucleophiles but 3-Chloropyridine Does Not
- Question 13: Proposed Syntheses of Two Amines
December 2015
- Question 1: Functional-Group Feasibility, Dehydration & Hydration
- Question 2: Alkane/Haloalkane Nomenclature & Hydrogenation
- Question 3: Ester & Disulfide Isomers; Acid-Catalysed Transesterification
- Question 4: Hydrogenation, Markovnikov Addition, Nitration & Double Benzylic Oxidation
- Question 5: Hydrogenation, Multi-Step Synthesis & Carbon Classification
May 2015
- Question 1: Functional-Group Structural Isomers
- Question 2: Electrophilic Addition to Alkenes
- Question 3: Alkene Stability & Markovnikov Mechanism
- Question 4: Multi-Step Aromatic Synthesis & Alkene Stability
- Question 5: Electrophilic Aromatic Substitution Mechanisms & Combustion
December 2014
- Question 1: Functional-Group Feasibility & Alkene/Arene Hydration
- Question 2: Alkane/Haloalkane Nomenclature & Catalytic Hydrogenation
- Question 3: Alkene Isomers, Friedel–Crafts Acylation Mechanism & Combustion
- Question 4: Carbon Classification, Hydrogenation, Markovnikov Addition & Nitration
- Question 5: Multi-Step Synthesis, Enantiomers & Double Benzylic Oxidation
May 2014
- Question 1: Carbon Classification & Alkene Stability Ranking
- Question 2: Benzylic Oxidation & Alkene Addition Reactions
- Question 3: Multi-Step Synthesis from Benzene & Cycloalkane Combustion
- Question 4: Friedel–Crafts Acylation Mechanism & Alkene Stability
- Question 5: Constitutional Isomers of C6H14 & Reaction Classification
December 2013
- Question 1: Iso-octane Structure, Carbon Classification & Family Identification
- Question 2: Isomers of C6H14, Cyclohexane Combustion & Propane Chlorination
- Question 3: Markovnikov Addition of HBr, Amine/Ether Structures & Methanol→Ethanol Synthesis
- Question 4: Pentyne-2 Addition Reactions & Butanol Isomer Differentiation
- Question 5: Ester/Alcohol Reactions, Dehydration & Hydrogenation of Butene Isomers
May 2013
- Question 1: Family Identification of Four Organic Compounds
- Question 2: Predicting the Products of Five Organic Reactions
- Question 3: Structures from Molecular Formulas; Combustion of a Substituted Cyclohexane
- Question 4: Alkene Geometric Isomers, a Friedel–Crafts Mechanism, and Alkene Stability
- Question 5: Constitutional Isomers of C 7 H 16 ; Classifying Three Alkene Reactions