Question 1

Which of the following statements best explains why alkanes are generally unreactive under normal laboratory conditions?

Accepted Answer

Alkanes have strong and non-polar C–C and C–H bonds, making them resistant to most chemical reactions.

Question 2

How many constitutional isomers are possible for the molecular formula $C_6H_{14}$?

Accepted Answer

$5$

Question 3

Which of the following compounds is a secondary alcohol?

Accepted Answer

$R_2CH-OH$

Question 4

Which type of intermolecular force is primarily responsible for the high boiling point of ethanol compared to propane?

Accepted Answer

Hydrogen bonding

Question 5

Which of the following statements about constitutional isomers is correct?

Accepted Answer

They have the same molecular formula but different atom connectivity.

Question 6

Which of the following best describes a tertiary amine?

Accepted Answer

$R_3N$

Question 7

Why does pentane ($C_5H_{12}$) have a higher boiling point than 2,2-dimethylpropane ($C_5H_{12}$)?

Accepted Answer

Pentane has a larger surface area, leading to stronger van der Waals forces.

Question 8

Which of the following is true about the chair conformation of cyclohexane?

Accepted Answer

It is the most stable conformation due to minimal angle and torsional strain.

Question 9

A compound has the formula $C_4H_{10}$. Which of the following statements is correct?

Accepted Answer

It can exist as two constitutional isomers: butane and isobutane.

Question 10

Which of the following best explains why cyclopropane is highly strained?

Accepted Answer

Its bond angles are much less than the ideal tetrahedral angle, causing angle strain.

Question 11

Which of the following statements about cis-trans isomerism in cycloalkanes is correct?

Accepted Answer

Cis and trans isomers have the same molecular formula and connectivity but different spatial arrangements.

Question 12

Which of the following is the most stable conformation for trans-1,4-dimethylcyclohexane?

Accepted Answer

Both methyl groups in equatorial positions.

Question 13

Which of the following best describes the effect of a ring flip in cyclohexane?

Accepted Answer

Axial substituents become equatorial and vice versa.

Question 14

Which of the following is a primary alkyl halide?

Accepted Answer

$R-CH_2-Br$

Question 15

Which of the following compounds would you expect to have the highest boiling point?

Accepted Answer

Ethanol ($CH_3CH_2OH$)

Question 16

Which of the following best explains why tertiary amines have lower boiling points than primary amines of similar molecular mass?

Accepted Answer

Tertiary amines cannot form intermolecular hydrogen bonds.

Question 17

Which of the following statements about van der Waals forces is correct?

Accepted Answer

They increase with increasing molecular surface area.

Question 18

Which of the following best describes the difference between a constitutional isomer and a conformer?

Accepted Answer

Constitutional isomers have different atom connectivity, while conformers differ by rotation around single bonds.

Question 19

Which of the following best explains why large substituents prefer the equatorial position in cyclohexane chair conformations?

Accepted Answer

The equatorial position is less crowded, minimizing steric strain.

Question 20

Which of the following best describes the structure of cholesterol and other steroids?

Accepted Answer

They consist of four fused rings in a trans configuration, making the molecule relatively flat.

Introduction to Organic Compounds: Structure, Classification, and Properties

Study Guide - Practice Questions