Question 1

Which of the following statements best explains why meso-tartaric acid is optically inactive, despite having chiral centers?

Accepted Answer

It contains a plane of symmetry, making the molecule achiral and thus optically inactive.

Question 2

How many stereoisomers are possible for a molecule with three chiral centers and no plane of symmetry?

Accepted Answer

$$2^3 = 8$

Question 3

Which of the following best describes the relationship between (2R,3S)-3-chloro-4-methylhexane and (2S,3R)-3-chloro-4-methylhexane?

Accepted Answer

They are enantiomers.

Question 4

A compound has the following Fischer projection:

$$\begin{array}{c} COOH \ | \ H-C-OH \ | \ HO-C-H \ | \ COOH \end{array}$$

Which form of tartaric acid does this represent?

Accepted Answer

meso-tartaric acid

Question 5

Which of the following is true about the S enantiomer of naproxen (Aleve)?

Accepted Answer

It is the active anti-inflammatory agent and is sold as the single enantiomer.

Question 6

Ibuprofen is sold as a racemic mixture. What happens to the R enantiomer in the human body?

Accepted Answer

It is converted to the S enantiomer, which is the active form.

Question 7

Which of the following best describes a meso compound?

Accepted Answer

A compound with chiral centers that is achiral due to a plane of symmetry.

Question 8

Which of the following is NOT a type of stereoisomerism described in the provided materials?

Accepted Answer

Structural isomerism

Question 9

A molecule has two chiral centers and a plane of symmetry. How many stereoisomers does it have?

Accepted Answer

3

Question 10

Which of the following statements about Fischer projections is correct?

Accepted Answer

The most oxidized carbon is placed at the top, and the configuration at the lowest chiral center determines D or L.

Question 11

Which of the following best describes the process of resolving a racemic mixture using a chiral compound?

Accepted Answer

It forms diastereomers with different physical properties, allowing separation.

Question 12

Which of the following is true about the relationship between (R)-ephedrine and (S)-ephedrine?

Accepted Answer

They are enantiomers.

Question 13

What is the maximum number of stereoisomers for a molecule with $$n$$ chiral centers?

Accepted Answer

$$2^n$$

Question 14

Which of the following is a correct statement about diastereomers?

Accepted Answer

They are stereoisomers that are not mirror images of each other.

Question 15

Which of the following best describes the difference between conformational and configurational isomers?

Accepted Answer

Conformational isomers can interconvert by rotation around single bonds, while configurational isomers require bond breaking to interconvert.

Question 16

Which of the following is a real-world example of the importance of stereochemistry in pharmaceuticals?

Accepted Answer

The S enantiomer of naproxen is active, while the R enantiomer is inactive and not sold.

Question 17

Which of the following statements about enantiomers is correct?

Accepted Answer

They have identical physical properties except for the direction in which they rotate plane-polarized light.

Question 18

Which of the following is true about the optical activity of a racemic mixture?

Accepted Answer

It is optically inactive because the rotations of the two enantiomers cancel each other.

Question 19

Which of the following best describes an epimer?

Accepted Answer

A diastereomer that differs in configuration at only one chiral center.

Question 20

Which of the following is a correct statement about the D and L notation in carbohydrates?

Accepted Answer

It refers to the configuration at the chiral center farthest from the carbonyl group.

Stereochemistry: Concepts, Isomerism, and Applications

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