ACS Review Stereochemistry - Practice Questions - Stereochemistry

Sep 21, 2026

ACS Review Stereochemistry provides a structured set of multiple-choice practice problems focused on stereochemistry and chirality. The questions cover identifying chiral molecules, determining stereogenic centers, assigning R/S configurations in general structures and Fischer projections, and applying the Cahn–Ingold–Prelog priority rules. Additional topics include enantiomer vs diastereomer relationships, optical activity and specific rotation calculations, meso stereoisomer identification, and stereochemical outcomes of reactions such as bromination, HBr addition, epoxidation, and hydrogenation.

LanguageEnglish

CategoryExam

FormatPDF

Pages15

Reading Time38 min

AccessFree to download

Stereochemistry Practice Questions

Chirality and Stereogenic Centers

R/S Configuration and Priority Rules

Stereoisomer Relationships and Optical Activity

Reaction Stereochemical Outcomes

ACS Review Stereochemistry 1. Which of the molecules below are chiral? A. only II B. only III C. I and III D. II and III 2. Which of the molecules below are chiral? A. only I B. I and III C. II and III D. I, II, and III 3. Identify the chiral compound(s) below. A. only II B. II and III C. III and IV D. I, II, and IV 4. Which of the following molecules are chiral? A. only II B. only III C. II and III D. I, II, and III 5. How many stereogenic centers are there in the following molecule? A. only 1 B. two C. three D. four 6. How many stereogenic centers are there in the following molecule? A. only 1 B. two C. three D. four 7. Give the configurations, respectively, of the following two molecules. A. R and R B. R and S C. S and S D. S and R 8. Give the configurations, respectively, of the following two molecules. A. R and R B. R and S C. S and S D. S and R 9. Which one of the following groups has the highest rank as assigned by the Cahn-Ingold-Prelog system for stereogenic carbons? A. -CH=CH2 B. -CH2OH C. -CH=O D. -CH2 SH 10. Give the configurations of carbons 1 and 2, respectively, in the structure shown below. A. R and R B. R and S C. S and S D. S and R 11. What is the IUPAC name of the following compound. A. (2S, 3S)-2,3-dibromopentane B. (2S, 3R)-2,3-dibromopentane C. (2R, 3S)-2,3-dibromopentane D. (2R, 3R)-2,3-dibromopentane 12. Which of the following statements are true. I. Ifa molecule has a plane of symmetry it is achiral. II. Ifa molecule has a center of symmetry it is achiral. III. Ifa molecule has one stereogenic center it is chiral. A. I and II B. I and III C. II and III D. I, II, and III 13. What is the relationship between the following two molecules? A. identical B. enantiomers C. diastereomers D. constitutional isomers 14. What are the configurations of carbons 2 and 3 in the Fischer projection below. A. 2R, 3R B. 2R, 3S C. 2S, 3R D. 2S, 3S 15. Compound X, C5H 10O, is optically active. The compound consumes one equivalent of hydrogen to give C5H 12O. The hydrogenation product is also optically active. Which compound below matches the information? A. A B. B C. C D. D 16. A pure sample of (S)-phenylalanine has a specific rotation of +70°. A mixture of the two enantiomers of phenylalanine has a specific rotation of +7.0°. What are the percentages ofthe S and R enantiomers in the mixture? A. 95% S, 5% R B. 90% S, 10% R C. 55% S, 45% R D. 52. 5% S, 47. 5% R 17. How many stereoisomers are there for the compound shown below? A. two B. four C. six D. eight 18. Give the total number of stereoisomers of 2,3-dibromobutane. A. none, only a single structure B. two C. three D. four 19. What is the relationship between the following two compounds? A. identical B. enantiomers C. diastereomers D. constitutional isomers 20. What is the relationship between the following two compounds? A. different conformations ofthe same compound B. enantiomers C. diastereomers D. constitutional isomers 21. (+)-Tartaric acid has a specific rotation of +12.0°. What is the specific rotation of a mixture of 75%(+) -tartaric acid and 25%(-)-tartaric acid? A. B. C. D. ° +4.0 ° +6.0 ° +8.0 ° +9.0 22. The addition of bromine, Br2 , to trans-2-butene gives: A. (2R,3R)-2,3-dibromobutane B. (2S,3S)-2,3-dibromobutane C. a racemic mixture of (2R,3R) and (2S,3S)-2,3-dibromobutane D. meso-2,3-dibromobutane 23. What is the relationship between the following two compounds? A. identical B. enantiomers C. diastereomers D. constitutional isomers 24. In terms of stereochemistry, the following reaction gives: A. a single enantiomer B. a racemic pair of enantiomers C. a nonracemic pair of enantiomers D. two diastereomers 25. Which of the following has a meso stereoisomer? I. 2,4-dichloropentane II. 1,3-dimeth

FAQs

How can you determine whether a molecule is chiral from the options given?

Use symmetry considerations and stereocenter/shape properties to select the option that contains chiral structures. The problems explicitly ask for which numbered molecules are chiral or identify chiral compounds among several candidates.

What methods are used to assign R/S configurations in these questions?

The set uses Cahn–Ingold–Prelog ranking for stereogenic carbons and asks for configurations either from drawn structures or from Fischer projections. Several questions require “respectively” assignments of two carbons.

How do the problems distinguish enantiomers, diastereomers, and constitutional isomers?

Each related-pairs question asks for the correct relationship among two compounds: identical, enantiomers, diastereomers, or constitutional isomers. The correct choice depends on whether mirror-image stereochemistry, relative configurations, or connectivity differs.

Sep 21, 2026

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