Question

Which of the following represents the increasing order of boiling points of (1), (2), and (3)?

(1) CH₃ - CH₂ - CH₂ - CH₂ - OH

(2) (CH₃)₂CHOCH₃

(3) (CH₃)₃COH

Options

• (1) < (2) < (3)

• (2) < (1) < (3)

• (3) < (2) < (1)

• (2) < (3) < (1)

Answer 1

(2) < (3) < (1)

Explanation:

The boiling point of a compound is determined by its intermolecular forces. The stronger the intermolecular forces, the higher the boiling point. In this case, we can compare the compounds based on the strength of their intermolecular forces.

(1) CH₃ - CH₂ - CH₂ - CH₂ - OH is an alcohol, with the hydroxyl group (OH) capable of forming hydrogen bonds.

(2) (CH₃)₂CHOCH₃ is a ketone, which can form dipole-dipole interactions.

(3) (CH₃)₃COH is a tertiary alcohol, also capable of forming hydrogen bonds.

Since hydrogen bonding is stronger than dipole-dipole interactions and tertiary alcohols have more steric hindrance, we can conclude that the increasing order of boiling points is (2) < (3) < (1).