Stereochemistry: Understanding Molecular 3D Structure and Interactions

Question 1

Which of the following properties is a characteristic of a chiral molecule?

Accepted Answer

It exhibits optical activity

Answer

It has a plane of symmetry

Answer

Its mirror images are superimposable

Question 2

Which of the following is NOT a type of isomerism found in organic compounds?

Accepted Answer

Metamerism

Answer

Structural isomerism

Answer

Stereoisomerism

Answer

Geometric isomerism

Question 3

Which of the following molecules is chiral?

Accepted Answer

CH3CH2OH

Answer

H2O

Answer

CO2

Answer

CH2Cl2

Question 4

What is the relationship between a pair of enantiomers?

Accepted Answer

They are mirror images of each other.

Answer

They have the same physical properties.

Answer

They have opposite optical activities.

Answer

They have the same chemical properties.

Question 5

Which of the following techniques can be used to separate a pair of enantiomers?

Accepted Answer

Chromatography

Answer

Distillation

Answer

Crystallization

Answer

Extraction

Question 6

What is the hybridization of the carbon atom in a tetrahedral chiral center?

Accepted Answer

sp3

Answer

sp

Answer

sp2

Answer

sp3d

Question 7

Which of the following molecules has a plane of symmetry?

Accepted Answer

CCl4

Answer

CH3Cl

Answer

CH2Cl2

Answer

CHCl3

Question 8

Which of the following is NOT a type of stereoisomerism?

Accepted Answer

Constitutional isomers

Answer

Enantiomers

Answer

Diastereomers

Answer

Meso compounds

Question 9

Which of the following functional groups is not a stereogenic center?

Accepted Answer

Aldehyde

Answer

Amine

Answer

Alcohol

Answer

Ketone

Question 10

The optical activity of a chiral compound is primarily determined by the:

Accepted Answer

Relative configuration of stereogenic centers

Answer

Number of stereogenic centers

Answer

Hybridization of stereogenic centers

Answer

Molecular weight of the compound

Question 11

Which of the following techniques is commonly used to separate enantiomers?

Accepted Answer

Chromatography

Answer

Recrystallization

Answer

Distillation

Answer

Extraction

Question 12

The Cahn-Ingold-Prelog (CIP) system is primarily used to:

Accepted Answer

Assign priority to substituents on a stereogenic center

Answer

Determine the absolute configuration of a chiral compound

Answer

Predict the optical activity of a chiral compound

Answer

Calculate the molecular weight of a chiral compound

Question 13

Enantiomers of a chiral compound have:

Accepted Answer

Different physical properties except optical rotation

Answer

Identical physical properties

Answer

Identical chemical properties

Answer

Different chemical properties

Question 14

Determine the absolute configuration (R/S) of the chiral molecule: CH3CH(OH)CH2Br

Accepted Answer

R

Answer

S

Answer

Cannot be determined

Answer

Racemic mixture

Question 15

Define a racemic mixture. Describe its optical properties and how it differs from a pure enantiomer.

Accepted Answer

A racemic mixture is an equal-parts combination of two enantiomers, resulting in zero optical activity.

Answer

A racemic mixture comprises equal parts of two diastereomers, exhibiting non-zero optical activity.

Answer

A racemic mixture is a combination of one enantiomer and one achiral molecule, resulting in non-zero optical activity.

Answer

A racemic mixture is a combination of two enantiomers in unequal amounts, exhibiting zero optical activity.

Question 16

Which of the following molecules is chiral?

Accepted Answer

2-butanol

Answer

methane

Answer

carbon dioxide

Answer

ethanoic acid

Question 17

Identify the optically active molecule:

Accepted Answer

(R)-2-butanol

Answer

2-methylpropane

Answer

meso-2,3-butanediol

Question 18

According to the Cahn-Ingold-Prelog (CIP) sequencing rules, which of the following groups has the highest priority?

Accepted Answer

COOH

Answer

OH

Answer

CH3

Answer

H

Question 19

Which of the following molecules is a stereoisomer of 2-butene?

Accepted Answer

cis-2-butene

Answer

butyne

Answer

2-methylpropene

Answer

1-butene

Question 20

Which of the following molecules is a meso compound?

Accepted Answer

2,3-pentanediol

Answer

2-chlorobutane

Answer

1,2-dibromoethane

Answer

2-butanol

Question 21

Which of the following molecules lacks a chiral center and is therefore achiral?

Accepted Answer

Ethane (CH3CH3)

Answer

2,3-Dibromobutane

Answer

1-Chloro-2-methylpropane

Answer

2-Butanol

Question 22

Which of the following reaction mechanisms is known to proceed with inversion of configuration at a chiral center?

Accepted Answer

SN2

Answer

E1

Answer

SN1

Answer

E2

Question 23

Which of the following statements is TRUE about diastereomers?

Accepted Answer

They are not mirror images of each other.

Answer

They have the same chemical properties.

Answer

They have the same physical properties.

Answer

They are always chiral.

Question 24

Which of the following techniques can be used to separate enantiomers, exploiting their subtle differences in interactions with a chiral stationary phase?

Accepted Answer

Chromatography

Answer

Extraction

Answer

Crystallization

Answer

Distillation