Question 1

Which of the following statements best describes a pair of structural (constitutional) isomers?

Accepted Answer

They have the same molecular formula but different connectivity.

Question 2

Which type of isomerism is illustrated by the difference between cis-2-butene and trans-2-butene?

Accepted Answer

Geometric (cis/trans) isomerism

Question 3

Which of the following pairs of molecules are mirror images but cannot be superimposed on each other?

Accepted Answer

Optical stereoisomers

Question 4

Given the molecular formula $$C_4H_{10}$$, which of the following is a constitutional isomer of butane?

Accepted Answer

2-methylpropane

Question 5

Which statement correctly distinguishes stereoisomers from structural isomers?

Accepted Answer

Stereoisomers have the same molecular formula and connectivity but different spatial orientation.

Question 6

Which of the following best describes a geometric stereoisomer?

Accepted Answer

Molecules with different spatial arrangements around a double bond.

Question 7

A student is given two molecules with the formula $$C_2H_6O. $$One is ethanol and the other is dimethyl ether. What type of isomers are these?

Accepted Answer

Structural (constitutional) isomers

Question 8

Which of the following is true about optical stereoisomers?

Accepted Answer

They are non-superimposable mirror images of each other.

Question 9

Which of the following molecules can exhibit cis-trans isomerism?

Accepted Answer

2-butene ($$CH_3CH=$$CHCH_3$$)

Question 10

Which of the following is NOT a requirement for a molecule to exhibit optical isomerism?

Accepted Answer

Presence of a double bond

Question 11

A compound has the formula $$C_3H_8O. $$Which of the following is a possible structural isomer?

Accepted Answer

2-propanol

Question 12

Which of the following best describes the difference between cis and trans isomers?

Accepted Answer

Cis isomers have substituents on the same side of a double bond, trans isomers have them on opposite sides.

Question 13

Which of the following is true about isomers?

Accepted Answer

Isomers have the same molecular formula but different connectivity or spatial orientation.

Question 14

Which of the following molecules is an example of a stereoisomer but NOT a structural isomer?

Accepted Answer

cis-2-butene and trans-2-butene

Question 15

Which of the following statements is correct regarding the relationship between enantiomers?

Accepted Answer

Enantiomers are non-superimposable mirror images.

Question 16

A molecule has a chiral center. Which type of isomerism can it exhibit?

Accepted Answer

Optical isomerism

Question 17

Which of the following is NOT a type of stereoisomer?

Accepted Answer

Structural isomer

Question 18

Which of the following best describes the relationship between 1-butene and 2-butene?

Accepted Answer

They are structural (constitutional) isomers.

Question 19

Which of the following is a requirement for a molecule to have geometric (cis/trans) isomers?

Accepted Answer

Presence of a double bond with different groups attached to each carbon.

Question 20

Which of the following pairs of molecules are identical?

Accepted Answer

Ethanol and ethanol

Isomerism in Organic Chemistry: Types and Examples

Study Guide - Practice Questions