Question 1

Which of the following best describes the relationship between the two hands shown in the second image?

Accepted Answer

They are nonsuperimposable mirror images and thus chiral.

Question 2

Which of the following statements about enantiomers is correct?

Accepted Answer

Enantiomers have identical physical properties except for their interaction with plane-polarized light.

Question 3

A molecule with the formula $$C_4H_{10}$$ can exist as which type of isomers?

Accepted Answer

Only constitutional isomers

Question 4

Which of the following molecules is chiral?

Accepted Answer

A molecule with a tetrahedral carbon bonded to four different groups

Question 5

Refer to the fourth image (labeled I and II). What is the relationship between molecules I and II?

Accepted Answer

They are enantiomers.

Question 6

Which of the following is true about a racemic mixture?

Accepted Answer

It causes no net rotation of plane-polarized light.

Question 7

How many stereoisomers are possible for a molecule with three chirality centers?

Accepted Answer

$$2^3 = 8$

Question 8

Which of the following best describes a meso compound?

Accepted Answer

An achiral compound with stereocenters and a plane of symmetry

Question 9

A sample of (S)-(+)-2-butanol has a specific rotation of $$+13.52. If a $$mixture of the two enantiomers shows a specific rotation of $$+6.76$$, what is the enantiomeric excess (ee) of (S)-(+)-2-butanol?

Accepted Answer

$$50\%$$

Question 10

Which of the following is a correct application of the Cahn-Ingold-Prelog priority rules for assigning R/S configuration?

Accepted Answer

If two atoms directly attached to the stereocenter are the same, the next set of atoms is examined.

Question 11

Which of the following statements about diastereomers is correct?

Accepted Answer

Diastereomers are stereoisomers that are not mirror images.

Question 12

Which of the following best explains why enantiomers have different effects in biological systems?

Accepted Answer

Biological systems are chiral and can distinguish between enantiomers.

Question 13

Which of the following is NOT a property of enantiomers?

Accepted Answer

They have different solubilities in achiral solvents.

Question 14

Which of the following molecules, as shown in the fifth image, is achiral?

Accepted Answer

The molecule with two identical methyl groups attached to the central carbon.

Question 15

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

Accepted Answer

It is a meso compound and achiral.

Question 16

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

Accepted Answer

$$ee = \frac{	ext{observed rotation}}{	ext{rotation of pure enantiomer}} 	imes 100\%$$

Question 17

Which of the following best describes the difference between constitutional isomers and stereoisomers?

Accepted Answer

Constitutional isomers have different connectivity, while stereoisomers have the same connectivity but differ in spatial arrangement.

Question 18

Which of the following is a correct statement about the maximum number of stereoisomers for a molecule with $$n$$ stereocenters?

Accepted Answer

The maximum number is $$2^n.$$

Question 19

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

Accepted Answer

One enantiomer of a drug can be therapeutic, while the other can be harmful.

Stereochemistry and Chirality: Chiral Molecules and Isomerism

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