Question 1

Which of the following statements best describes constitutional isomers?

Accepted Answer

They have the same molecular formula but a different bonding sequence.

Question 2

Which of the following compounds is chiral?

Accepted Answer

2-Butanol

Question 3

A molecule that has a plane of symmetry is most likely:

Accepted Answer

Achiral

Question 4

Which of the following best describes enantiomers?

Accepted Answer

They are nonsuperimposable mirror images.

Question 5

Given the following Fischer projection, assign the configuration at the chiral center using the Cahn-Ingold-Prelog rules:

$$\begin{array}{c}
\mathrm{Br} \
| \
\mathrm{C}^* \
/ \ \mathrm{Cl} \quad \mathrm{CH}_3 \
\end{array}$$

with H in the back. What is the configuration?

Accepted Answer

$$S$$

Question 6

Which of the following is NOT a requirement for a carbon atom to be considered an asymmetric center?

Accepted Answer

It must be part of a ring structure.

Question 7

Which of the following pairs are stereoisomers but NOT enantiomers?

Accepted Answer

cis-2-butene and trans-2-butene

Question 8

A compound has two asymmetric carbons. Which of the following statements is TRUE?

Accepted Answer

It may or may not be chiral, depending on the presence of a plane of symmetry.

Question 9

Which of the following best describes the relationship between (R)-2-butanol and (S)-2-butanol?

Accepted Answer

They are enantiomers.

Question 10

Which of the following statements about enantiomers is FALSE?

Accepted Answer

They can be separated by distillation.

Question 11

A student is asked to determine if a molecule is chiral. Which of the following is the best first step?

Accepted Answer

Check for the presence of a plane of symmetry.

Question 12

Which of the following molecules is achiral?

Accepted Answer

2,3-dibromobutane (meso form)

Question 13

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 atom of higher atomic number directly attached to the chiral center.

Question 14

Which of the following best describes a meso compound?

Accepted Answer

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

Question 15

If a molecule has the following structure:

$$\mathrm{CH}_3-\mathrm{CH}(\mathrm{OH})-\mathrm{CH}_2-\mathrm{CH}_3$$

How many asymmetric centers does it have?

Accepted Answer

1

Question 16

Which of the following is true about the mirror images of chiral molecules?

Accepted Answer

They are always nonsuperimposable.

Question 17

Which of the following is an example of a real-world application of chirality?

Accepted Answer

The different smells of enantiomers of limonene (orange vs. lemon scent).

Question 18

A compound has the following structure:

$$\mathrm{CH}_3-\mathrm{CHBr}-\mathrm{CHCl}-\mathrm{CH}_3$$

How many stereocenters are present?

Accepted Answer

2

Question 19

Which of the following statements about stereoisomers is correct?

Accepted Answer

They have the same molecular formula and the same connectivity but differ in the spatial arrangement of atoms.

Stereochemistry: Isomers, Chirality, and Asymmetric Centers (Wade 9e, Chapter 5 Outline)

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