Question 1

Which of the following statements best describes a chiral molecule?

Accepted Answer

A molecule that is not superimposable on its mirror image.

Question 2

Which of the following is a necessary condition for a carbon atom to be a chirality center?

Accepted Answer

It must be bonded to four different groups.

Question 3

A sample contains 6.0 g of $$(+)-2-$$butanol and 4.0 g of $$(-)-2-$$butanol. If the specific rotation of pure $$(+)-2-$$butanol is $$+13.5^\circ$$, what is the enantiomeric excess (ee) of the sample?

Accepted Answer

$$ee = 40\%$$

Question 4

Which of the following best describes a racemic mixture?

Accepted Answer

A mixture containing equal amounts of both enantiomers.

Question 5

Which property is identical for a pair of pure enantiomers?

Accepted Answer

Their boiling points.

Question 6

A molecule has two chirality centers but is achiral. What is this type of compound called?

Accepted Answer

Meso compound

Question 7

Which of the following is NOT a method for distinguishing between enantiomers?

Accepted Answer

Measuring their boiling points.

Question 8

According to the Cahn–Ingold–Prelog rules, which group has the highest priority when assigning R/S configuration to a chirality center?

Accepted Answer

$$-Br$$

Question 9

Which of the following statements about optical activity is correct?

Accepted Answer

A sample with enantiomeric excess will rotate plane-polarized light.

Question 10

Which of the following best describes the relationship between cis- and trans-1,3-dimethylcyclopentane?

Accepted Answer

They are diastereomers.

Question 11

A molecule has a plane of symmetry. Which of the following is true?

Accepted Answer

The molecule is achiral.

Question 12

Which of the following is a correct statement about Fischer projections?

Accepted Answer

Horizontal bonds point toward the viewer.

Question 13

Which of the following is true about the R/S system for assigning configuration?

Accepted Answer

A counterclockwise sequence from 1 to 3 gives the S configuration.

Question 14

Which of the following is a real-world example of chirality affecting biological function?

Accepted Answer

The smell of enantiomers to olfactory receptors.

Question 15

Which of the following statements about amines is correct?

Accepted Answer

Amines rapidly interconvert between enantiomers at room temperature.

Question 16

How many stereoisomers are possible for a molecule with three chirality centers, assuming no symmetry?

Accepted Answer

$$8$$

Question 17

Which of the following best describes the process of resolution in stereochemistry?

Accepted Answer

Separating enantiomers using a chiral substance to form diastereomers.

Question 18

Which of the following is true about meso compounds?

Accepted Answer

They contain chirality centers but are achiral due to symmetry.

Question 19

Which of the following is NOT a configurational isomer?

Accepted Answer

Conformer

Question 20

Which of the following is a correct formula for calculating enantiomeric excess (ee)?

Accepted Answer

$$ee = \frac{	ext{amount of one enantiomer} - 	ext{amount of the other}}{	ext{total amount}} 	imes 100$$

Chirality and Stereochemistry: An Introduction to Enantiomers and Stereoisomers

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