Question 1

Which of the following statements best describes a chiral center in an organic molecule?

Accepted Answer

A carbon atom bonded to four different substituents.

Question 2

Which of the following molecules is chiral?

Accepted Answer

CH$$_3CH(OH)$$COOH

Question 3

A molecule that is not superimposable on its mirror image is called:

Accepted Answer

Chiral

Question 4

Which of the following best explains why lactic acid is optically active?

Accepted Answer

It has a chiral center with four different groups attached.

Question 5

What is the relationship between D-glucose and L-glucose?

Accepted Answer

They are enantiomers.

Question 6

Which of the following is true about a racemic mixture?

Accepted Answer

It does not rotate plane-polarized light.

Question 7

Which of the following compounds would be expected to have a plane of symmetry?

Accepted Answer

Methylcyclohexane

Question 8

Which of the following best describes the Cahn-Ingold-Prelog sequence rule for assigning priorities?

Accepted Answer

Assign priorities based on atomic number; higher atomic number gets higher priority.

Question 9

A solution of (+)-sucrose rotates plane-polarized light to the:

Accepted Answer

Right (clockwise)

Question 10

Which of the following is NOT a property of enantiomers?

Accepted Answer

They are superimposable on each other.

Question 11

Which of the following best describes an achiral molecule?

Accepted Answer

A molecule that is identical to its mirror image.

Question 12

Which of the following is a correct statement about optical activity?

Accepted Answer

Molecules that rotate plane-polarized light are said to be optically active.

Question 13

Which of the following is the correct order of priority for the following substituents attached to a chiral center: Br, Cl, S, O?

Accepted Answer

$$\mathrm{Br} \u003e \mathrm{S} \u003e \mathrm{Cl} \u003e \mathrm{O}$$

Question 14

Which of the following best describes the difference between absolute and relative configuration?

Accepted Answer

Absolute configuration is the actual spatial arrangement of atoms, while relative configuration is described relative to another chiral center or standard.

Question 15

Which of the following is a correct application of the Cahn-Ingold-Prelog rules when two substituents have the same first atom?

Accepted Answer

Compare the atomic numbers of the next set of atoms along the chain until a difference is found.

Question 16

Which of the following best explains why a racemic mixture is optically inactive?

Accepted Answer

The optical rotations of the two enantiomers cancel each other out.

Question 17

Which of the following is an example of a real-world consequence of molecular handedness?

Accepted Answer

Enzymes can distinguish between enantiomers, leading to different biological effects.

Question 18

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

Accepted Answer

2-methylpropane

Question 19

Which of the following best describes the effect of a molecule with a plane of symmetry?

Accepted Answer

It is achiral and superimposable on its mirror image.

Question 20

Which of the following is the correct application of Rule 3 of the Cahn-Ingold-Prelog sequence rules?

Accepted Answer

A carbon doubly bonded to oxygen is equivalent to a carbon singly bonded to two oxygens.

Stereochemistry & Chirality: Foundations and Applications

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