PHARMD • MEDICINAL CHEMISTRY • ORIGINAL PRACTICE RESOURCE
PharmD Medicinal Chemistry
2026–2027 Practice Examination & Review
110 original multiple-choice items • 55 foundational medicinal-chemistry concepts assessed through
direct recall and applied scenarios • Answer rationales and distractor explanations • Consolidated
answer key
Educational disclaimer: Not an official university examination or proprietary test bank. Clinical
application requires current references and professional judgment. All scenarios are hypothetical.
Exam Instructions
Choose the single best answer (A–D). Each item includes an answer and teaching explanation for
self-study. The second half revisits the same 55 concepts in application-oriented scenarios, rather
than representing 110 independent topics.
Part I — Foundational Knowledge (Questions 1–55)
1. [Acid–base chemistry] Which group is typically ionized as an anion at physiological pH?
A. Amide
B. Carboxylic acid
C. Ester
D. Ketone
Correct answer: B. Carboxylic acid
Detailed rationale: Carboxylic acids commonly have pKa near 4–5 and are mostly
deprotonated at pH 7.4.
Why the other options are incorrect: A (Amide) does not satisfy the specified feature or
mechanism; C (Ester) does not satisfy the specified feature or mechanism; D (Ketone) does not
satisfy the specified feature or mechanism;
2. [Acid–base chemistry] Which functional group is commonly a weak base that can
become protonated?
A. Nitrile
B. Tertiary amine
C. Ester
D. Carboxylic acid
Correct answer: B. Tertiary amine
Detailed rationale: A tertiary amine has a nitrogen lone pair and can accept a proton; extent
depends on pKa.
Why the other options are incorrect: A (Nitrile) does not satisfy the specified feature or
mechanism; C (Ester) does not satisfy the specified feature or mechanism; D (Carboxylic acid)
does not satisfy the specified feature or mechanism;
3. [Acid–base chemistry] At pH below the pKa of a weak acid, which form predominates?
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A. Zwitterion necessarily
B. Doubly charged cation
C. Deprotonated anion
D. Protonated neutral acid
Correct answer: D. Protonated neutral acid
Detailed rationale: Henderson–Hasselbalch predicts HA predominates when pH is below pKa.
Why the other options are incorrect: A (Zwitterion necessarily) does not satisfy the specified
feature or mechanism; B (Doubly charged cation) does not satisfy the specified feature or
mechanism; C (Deprotonated anion) does not satisfy the specified feature or mechanism;
4. [Acid–base chemistry] At pH below the pKa of a weak base’s conjugate acid, which form
predominates?
A. Protonated cation
B. Uncharged free base
C. Carboxylate anion
D. Covalent hydrate
Correct answer: A. Protonated cation
Detailed rationale: For BH+ ⇌ B + H+, pH below pKa favors BH+.
Why the other options are incorrect: B (Uncharged free base) does not satisfy the specified
feature or mechanism; C (Carboxylate anion) does not satisfy the specified feature or
mechanism; D (Covalent hydrate) does not satisfy the specified feature or mechanism;
5. [Lipophilicity] What does a larger logP generally indicate for a neutral molecule?
A. Higher aqueous solubility always
B. Greater octanol affinity
C. Higher molecular mass necessarily
D. Greater ionization
Correct answer: B. Greater octanol affinity
Detailed rationale: logP measures partitioning of the neutral form between octanol and water;
higher values generally reflect greater lipophilicity.
Why the other options are incorrect: A (Higher aqueous solubility always) does not satisfy the
specified feature or mechanism; C (Higher molecular mass necessarily) does not satisfy the
specified feature or mechanism; D (Greater ionization) does not satisfy the specified feature or
mechanism;
6. [Lipophilicity] Which descriptor includes ionization at a specified pH?
A. logP only
B. logD
C. Polarizability only
D. Melting point
Correct answer: B. logD
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Detailed rationale: logD is the distribution coefficient at a specified pH and reflects all
ionization states.
Why the other options are incorrect: A (logP only) does not satisfy the specified feature or
mechanism; C (Polarizability only) does not satisfy the specified feature or mechanism; D
(Melting point) does not satisfy the specified feature or mechanism;
7. [Solubility] Which change often improves aqueous solubility of a basic drug?
A. Increasing aromatic ring count
B. Adding multiple nonpolar alkyl groups
C. Removal of all heteroatoms
D. Formation of an appropriate acid-addition salt
Correct answer: D. Formation of an appropriate acid-addition salt
Detailed rationale: Protonating a basic center and preparing a suitable salt can improve
dissolution, though solid-state factors matter.
Why the other options are incorrect: A (Increasing aromatic ring count) does not satisfy the
specified feature or mechanism; B (Adding multiple nonpolar alkyl groups) does not satisfy
the specified feature or mechanism; C (Removal of all heteroatoms) does not satisfy the
specified feature or mechanism;
8. [Solubility] What is a common risk of excessive lipophilicity in a drug candidate?
A. Poor aqueous solubility
B. Complete avoidance of metabolism
C. Guaranteed high oral bioavailability
D. Zero plasma protein binding
Correct answer: A. Poor aqueous solubility
Detailed rationale: Highly lipophilic compounds often have solubility and nonspecific-binding
liabilities.
Why the other options are incorrect: B (Complete avoidance of metabolism) does not satisfy
the specified feature or mechanism; C (Guaranteed high oral bioavailability) does not satisfy
the specified feature or mechanism; D (Zero plasma protein binding) does not satisfy the
specified feature or mechanism;
9. [Stereochemistry] What are enantiomers?
A. Constitutional isomers
B. Identical conformers
C. Nonsuperimposable mirror-image stereoisomers
D. Diastereomers by definition
Correct answer: C. Nonsuperimposable mirror-image stereoisomers
Detailed rationale: Enantiomers are mirror images that cannot be superimposed; biological
targets may distinguish them.
Why the other options are incorrect: A (Constitutional isomers) does not satisfy the specified
feature or mechanism; B (Identical conformers) does not satisfy the specified feature or
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mechanism; D (Diastereomers by definition) does not satisfy the specified feature or
mechanism;
10. [Stereochemistry] What distinguishes diastereomers from enantiomers?
A. They are stereoisomers not related as mirror images
B. They differ only in molecular formula
C. They have no stereocenters ever
D. They always have identical physical properties
Correct answer: A. They are stereoisomers not related as mirror images
Detailed rationale: Diastereomers are stereoisomers that are not mirror images and can have
different physical properties.
Why the other options are incorrect: B (They differ only in molecular formula) does not satisfy
the specified feature or mechanism; C (They have no stereocenters ever) does not satisfy the
specified feature or mechanism; D (They always have identical physical properties) does not
satisfy the specified feature or mechanism;
11. [Stereochemistry] Which property can differ between two enantiomers in a chiral
biological system?
A. Elemental composition
B. Number of covalent bonds
C. Molecular formula
D. Receptor affinity
Correct answer: D. Receptor affinity
Detailed rationale: Chiral proteins can bind enantiomers differently, leading to different
potency or toxicity.
Why the other options are incorrect: A (Elemental composition) does not satisfy the specified
feature or mechanism; B (Number of covalent bonds) does not satisfy the specified feature or
mechanism; C (Molecular formula) does not satisfy the specified feature or mechanism;
12. [Stereochemistry] What does a racemic mixture contain?
A. One pure stereoisomer
B. Equal amounts of all diastereomers
C. Equal amounts of two enantiomers
D. Only achiral compounds
Correct answer: C. Equal amounts of two enantiomers
Detailed rationale: A racemate is a 1:1 mixture of an enantiomeric pair.
Why the other options are incorrect: A (One pure stereoisomer) does not satisfy the specified
feature or mechanism; B (Equal amounts of all diastereomers) does not satisfy the specified
feature or mechanism; D (Only achiral compounds) does not satisfy the specified feature or
mechanism;
13. [Isomerism] Which isomerism results from rotation about single bonds?
A. Conformational isomerism
Independent educational material | 2026–2027 | 4
PharmD Medicinal Chemistry
2026–2027 Practice Examination & Review
110 original multiple-choice items • 55 foundational medicinal-chemistry concepts assessed through
direct recall and applied scenarios • Answer rationales and distractor explanations • Consolidated
answer key
Educational disclaimer: Not an official university examination or proprietary test bank. Clinical
application requires current references and professional judgment. All scenarios are hypothetical.
Exam Instructions
Choose the single best answer (A–D). Each item includes an answer and teaching explanation for
self-study. The second half revisits the same 55 concepts in application-oriented scenarios, rather
than representing 110 independent topics.
Part I — Foundational Knowledge (Questions 1–55)
1. [Acid–base chemistry] Which group is typically ionized as an anion at physiological pH?
A. Amide
B. Carboxylic acid
C. Ester
D. Ketone
Correct answer: B. Carboxylic acid
Detailed rationale: Carboxylic acids commonly have pKa near 4–5 and are mostly
deprotonated at pH 7.4.
Why the other options are incorrect: A (Amide) does not satisfy the specified feature or
mechanism; C (Ester) does not satisfy the specified feature or mechanism; D (Ketone) does not
satisfy the specified feature or mechanism;
2. [Acid–base chemistry] Which functional group is commonly a weak base that can
become protonated?
A. Nitrile
B. Tertiary amine
C. Ester
D. Carboxylic acid
Correct answer: B. Tertiary amine
Detailed rationale: A tertiary amine has a nitrogen lone pair and can accept a proton; extent
depends on pKa.
Why the other options are incorrect: A (Nitrile) does not satisfy the specified feature or
mechanism; C (Ester) does not satisfy the specified feature or mechanism; D (Carboxylic acid)
does not satisfy the specified feature or mechanism;
3. [Acid–base chemistry] At pH below the pKa of a weak acid, which form predominates?
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A. Zwitterion necessarily
B. Doubly charged cation
C. Deprotonated anion
D. Protonated neutral acid
Correct answer: D. Protonated neutral acid
Detailed rationale: Henderson–Hasselbalch predicts HA predominates when pH is below pKa.
Why the other options are incorrect: A (Zwitterion necessarily) does not satisfy the specified
feature or mechanism; B (Doubly charged cation) does not satisfy the specified feature or
mechanism; C (Deprotonated anion) does not satisfy the specified feature or mechanism;
4. [Acid–base chemistry] At pH below the pKa of a weak base’s conjugate acid, which form
predominates?
A. Protonated cation
B. Uncharged free base
C. Carboxylate anion
D. Covalent hydrate
Correct answer: A. Protonated cation
Detailed rationale: For BH+ ⇌ B + H+, pH below pKa favors BH+.
Why the other options are incorrect: B (Uncharged free base) does not satisfy the specified
feature or mechanism; C (Carboxylate anion) does not satisfy the specified feature or
mechanism; D (Covalent hydrate) does not satisfy the specified feature or mechanism;
5. [Lipophilicity] What does a larger logP generally indicate for a neutral molecule?
A. Higher aqueous solubility always
B. Greater octanol affinity
C. Higher molecular mass necessarily
D. Greater ionization
Correct answer: B. Greater octanol affinity
Detailed rationale: logP measures partitioning of the neutral form between octanol and water;
higher values generally reflect greater lipophilicity.
Why the other options are incorrect: A (Higher aqueous solubility always) does not satisfy the
specified feature or mechanism; C (Higher molecular mass necessarily) does not satisfy the
specified feature or mechanism; D (Greater ionization) does not satisfy the specified feature or
mechanism;
6. [Lipophilicity] Which descriptor includes ionization at a specified pH?
A. logP only
B. logD
C. Polarizability only
D. Melting point
Correct answer: B. logD
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Detailed rationale: logD is the distribution coefficient at a specified pH and reflects all
ionization states.
Why the other options are incorrect: A (logP only) does not satisfy the specified feature or
mechanism; C (Polarizability only) does not satisfy the specified feature or mechanism; D
(Melting point) does not satisfy the specified feature or mechanism;
7. [Solubility] Which change often improves aqueous solubility of a basic drug?
A. Increasing aromatic ring count
B. Adding multiple nonpolar alkyl groups
C. Removal of all heteroatoms
D. Formation of an appropriate acid-addition salt
Correct answer: D. Formation of an appropriate acid-addition salt
Detailed rationale: Protonating a basic center and preparing a suitable salt can improve
dissolution, though solid-state factors matter.
Why the other options are incorrect: A (Increasing aromatic ring count) does not satisfy the
specified feature or mechanism; B (Adding multiple nonpolar alkyl groups) does not satisfy
the specified feature or mechanism; C (Removal of all heteroatoms) does not satisfy the
specified feature or mechanism;
8. [Solubility] What is a common risk of excessive lipophilicity in a drug candidate?
A. Poor aqueous solubility
B. Complete avoidance of metabolism
C. Guaranteed high oral bioavailability
D. Zero plasma protein binding
Correct answer: A. Poor aqueous solubility
Detailed rationale: Highly lipophilic compounds often have solubility and nonspecific-binding
liabilities.
Why the other options are incorrect: B (Complete avoidance of metabolism) does not satisfy
the specified feature or mechanism; C (Guaranteed high oral bioavailability) does not satisfy
the specified feature or mechanism; D (Zero plasma protein binding) does not satisfy the
specified feature or mechanism;
9. [Stereochemistry] What are enantiomers?
A. Constitutional isomers
B. Identical conformers
C. Nonsuperimposable mirror-image stereoisomers
D. Diastereomers by definition
Correct answer: C. Nonsuperimposable mirror-image stereoisomers
Detailed rationale: Enantiomers are mirror images that cannot be superimposed; biological
targets may distinguish them.
Why the other options are incorrect: A (Constitutional isomers) does not satisfy the specified
feature or mechanism; B (Identical conformers) does not satisfy the specified feature or
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mechanism; D (Diastereomers by definition) does not satisfy the specified feature or
mechanism;
10. [Stereochemistry] What distinguishes diastereomers from enantiomers?
A. They are stereoisomers not related as mirror images
B. They differ only in molecular formula
C. They have no stereocenters ever
D. They always have identical physical properties
Correct answer: A. They are stereoisomers not related as mirror images
Detailed rationale: Diastereomers are stereoisomers that are not mirror images and can have
different physical properties.
Why the other options are incorrect: B (They differ only in molecular formula) does not satisfy
the specified feature or mechanism; C (They have no stereocenters ever) does not satisfy the
specified feature or mechanism; D (They always have identical physical properties) does not
satisfy the specified feature or mechanism;
11. [Stereochemistry] Which property can differ between two enantiomers in a chiral
biological system?
A. Elemental composition
B. Number of covalent bonds
C. Molecular formula
D. Receptor affinity
Correct answer: D. Receptor affinity
Detailed rationale: Chiral proteins can bind enantiomers differently, leading to different
potency or toxicity.
Why the other options are incorrect: A (Elemental composition) does not satisfy the specified
feature or mechanism; B (Number of covalent bonds) does not satisfy the specified feature or
mechanism; C (Molecular formula) does not satisfy the specified feature or mechanism;
12. [Stereochemistry] What does a racemic mixture contain?
A. One pure stereoisomer
B. Equal amounts of all diastereomers
C. Equal amounts of two enantiomers
D. Only achiral compounds
Correct answer: C. Equal amounts of two enantiomers
Detailed rationale: A racemate is a 1:1 mixture of an enantiomeric pair.
Why the other options are incorrect: A (One pure stereoisomer) does not satisfy the specified
feature or mechanism; B (Equal amounts of all diastereomers) does not satisfy the specified
feature or mechanism; D (Only achiral compounds) does not satisfy the specified feature or
mechanism;
13. [Isomerism] Which isomerism results from rotation about single bonds?
A. Conformational isomerism
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