$$\begin{array}{c} \mathrm{CH_3$} \\ | \\ \mathrm{HO}-\mathrm{C^*}-\mathrm{CH_2CH_3} \\ | \\ \mathrm{H} \end{array}$$

Question 1

Which statement best describes constitutional (structural) isomers?

Accepted Answer

Molecules with the same chemical formula but different connectivity of atoms.

Question 2

How many constitutional isomers are possible for the alkane with the formula $$\mathrm{C_5H_{12}}$$?

Accepted Answer

3

Question 3

Which of the following molecules contains a chiral carbon atom?

Accepted Answer

2-butanol

Question 4

Optical isomerism arises when a molecule has:

Accepted Answer

Four different groups attached to a tetrahedral carbon atom

Question 5

Which of the following is true about enantiomers?

Accepted Answer

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

Question 6

What is the general formula for alkanes?

Accepted Answer

$$\mathrm{C_nH_{2n+2}}$$

Question 7

Which of the following is a correct statement about the number of constitutional isomers for alkanes as the number of carbon atoms increases?

Accepted Answer

The number of isomers increases rapidly.

Question 8

Which of the following is NOT a stereoisomer?

Accepted Answer

Constitutional isomer

Question 9

A molecule with two stereogenic centers can have a maximum of how many stereoisomers?

Accepted Answer

4

Question 10

Which of the following best describes a meso compound?

Accepted Answer

A compound with a plane of symmetry and is optically inactive.

Question 11

Which of the following is a correct application of the Cahn-Ingold-Prelog (R,S) nomenclature system?

Accepted Answer

Assign priorities based on atomic number, with the lowest priority group pointing away from the viewer.

Question 12

Which of the following is a correct statement about the physical properties of constitutional isomers?

Accepted Answer

They have different boiling and melting points.

Question 13

Which of the following is a correct example of a pair of constitutional isomers?

Accepted Answer

n-butane and 2-methylpropane

Question 14

Which of the following molecules will NOT exhibit optical activity?

Accepted Answer

A molecule with a plane of symmetry

Question 15

Which of the following is the correct Fischer projection for 2-butanol?

Accepted Answer

$$\begin{array}{c} \mathrm{CH_3$} \ | \ \mathrm{HO}-\mathrm{C^*}-\mathrm{CH_2CH_3} \ | \ \mathrm{H} \end{array}$$

Question 16

Which of the following is the correct IUPAC name for the alkene with the structure $$\mathrm{CH_3CH=CHCH_2CH_3}$$?

Accepted Answer

2-pentene

Question 17

Which of the following is a correct statement about the staggered conformation of butane?

Accepted Answer

It is more stable than the eclipsed conformation.

Question 18

Which of the following is a correct example of a geometric (cis-trans) isomer?

Accepted Answer

cis-1-bromo-2-chlorocyclopropane and trans-1-bromo-2-chlorocyclopropane

Question 19

Which of the following statements about diastereomers is correct?

Accepted Answer

They differ in physical properties such as melting point and solubility.

Isomerism in Organic Chemistry: Structural and Optical Isomers

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