Question 1

Which of the following best describes the difference between cis and trans isomers in alkenes?

Accepted Answer

Cis isomers have identical groups on the same side of the double bond, while trans isomers have them on opposite sides.

Question 2

Which statement about E/Z isomerism is correct?

Accepted Answer

The Z isomer has the highest priority groups on the same side of the double bond.

Question 3

Which of the following molecules is chiral?

Accepted Answer

A molecule with four different groups attached to a central carbon atom.

Question 4

How many stereoisomers are possible for a molecule with two asymmetric centers and no E/Z double bonds?

Accepted Answer

$$4$$

Question 5

Which of the following best describes enantiomers?

Accepted Answer

They are non-superimposable mirror images.

Question 6

A molecule has the following substituents on a double bond: Br, Cl, CH$$_3$$, and H. According to the Cahn-Ingold-Prelog rules, which group has the highest priority?

Accepted Answer

Br

Question 7

Which of the following statements about chirality in pharmaceuticals is correct?

Accepted Answer

The S-enantiomer of naproxen is anti-inflammatory, while the R-enantiomer is a liver toxin.

Question 8

Which of the following is NOT a stereoisomeric relationship?

Accepted Answer

Structural (constitutional) isomers

Question 9

Which of the following is true regarding the assignment of R/S configuration to an asymmetric center?

Accepted Answer

If the lowest priority group is on a wedge, assign the configuration as usual and then reverse it.

Question 10

Which of the following pairs of molecules are conformers?

Accepted Answer

Molecules that can be interconverted by rotation about a single bond.

Question 11

A compound has two stereogenic elements: one asymmetric center and one E/Z double bond. What is the maximum number of stereoisomers possible?

Accepted Answer

$$4$$

Question 12

Which of the following best describes a diastereomer?

Accepted Answer

A stereoisomer that is not a mirror image of another stereoisomer.

Question 13

Which of the following is NOT a criterion for a molecule to be chiral?

Accepted Answer

It must be superimposable on its mirror image.

Question 14

Which of the following statements about geometric (cis/trans) isomerism is correct?

Accepted Answer

Cis/trans isomerism is a type of configurational isomerism.

Question 15

Which of the following best describes a structural (constitutional) isomer?

Accepted Answer

Molecules with the same molecular formula but different connectivity of atoms.

Question 16

Which of the following is a correct application of the Cahn-Ingold-Prelog priority rules?

Accepted Answer

Assign higher priority to the group with the highest atomic number.

Question 17

Which of the following statements about conformational isomers is correct?

Accepted Answer

They can be interconverted by rotation about a single bond.

Question 18

Which of the following is NOT a stereogenic element?

Accepted Answer

A methyl group attached to a benzene ring

Question 19

Which of the following best describes the relationship between (R)-thalidomide and (S)-thalidomide?

Accepted Answer

They are enantiomers.

Question 20

Which of the following is true about the maximum number of stereoisomers for a molecule with $$n$$ asymmetric centers and no other stereogenic elements?

Accepted Answer

The maximum number is $$2^n.$$

Isomerism and Chirality in Organic Chemistry: Structured Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards