Question 1

Which of the following statements best describes a stereoisomer?

Accepted Answer

Molecules with the same composition but different spatial 3D arrangement of atoms.

Question 2

Which property is shared by malic acid and fumaric acid, as shown in the study material?

Accepted Answer

They are stereoisomers.

Question 3

A chiral center in a molecule is defined as:

Accepted Answer

A carbon atom bonded to four distinct chemical groups.

Question 4

Which of the following best describes resonance in organic molecules?

Accepted Answer

The delocalization of electrons within a molecule, leading to a stabilizing effect.

Question 5

Given the Fischer projection below, determine the configuration (R or S) of the chiral center:

$$\begin{array}{c}
\mathrm{COOH} \
\mathrm{H} - \mathrm{C} - \mathrm{CH}_3 \
\mathrm{NH}_2}
\end{array}$$

Accepted Answer

S

Question 6

Which statement about enantiomers is correct?

Accepted Answer

Enantiomers are nonsuperimposable mirror images that differ in chiral configuration.

Question 7

Which of the following is true about Fischer projections?

Accepted Answer

Horizontal bonds are popping out of the page as wedges.

Question 8

Consider the following molecule:

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

How many chiral centers does this molecule have?

Accepted Answer

1

Question 9

Which configuration describes the staggered conformation of ethane?

Accepted Answer

Hydrogens are as far apart as possible in 3D space.

Question 10

Which of the following is NOT a characteristic of a chiral molecule?

Accepted Answer

It is superimposable on its mirror image.

Question 11

Which of the following best explains why resonance structures are used in organic chemistry?

Accepted Answer

They provide a better representation of electron delocalization than a single Lewis structure.

Question 12

Which of the following is a correct statement about conformations?

Accepted Answer

Conformations are potentially flexible arrangements that can change by rotation around single bonds.

Question 13

A molecule with two chiral centers can have how many possible stereoisomers?

Accepted Answer

4

Question 14

Which of the following is the correct definition of a configuration in stereochemistry?

Accepted Answer

A fixed 3D arrangement only changed by breaking and reforming bonds.

Question 15

Which of the following molecules would NOT have a chiral center?

Accepted Answer

$$\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_3$$

Question 16

Which of the following is true about the R/S system for chiral centers?

Accepted Answer

R and S describe the absolute configuration of chiral centers based on priority rules.

Question 17

Which of the following is a real-world consequence of chirality in pharmaceuticals, as illustrated by thalidomide?

Accepted Answer

One enantiomer can be therapeutic while the other can be harmful.

Question 18

Which of the following best describes the difference between a configuration and a conformation?

Accepted Answer

Configuration is fixed and only changes by breaking bonds; conformation is flexible and changes by rotation around single bonds.

Question 19

Which of the following is the best representation of electron delocalization in a carboxylate ion?

Accepted Answer

A resonance hybrid showing delocalized electrons over both oxygens.

Question 20

Which of the following statements about Fischer projections is correct?

Accepted Answer

Vertical bonds are going into the page as dashes.

Stereochemistry, Resonance, and Fischer Projections in Organic Chemistry

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