Assertion-Reason:
Assertion (A): Butan-1-ol has a higher boiling point than ethoxyethane.
Reason (R): Extensive hydrogen bonding leads to stronger association of molecules.
Both A and R are true, but R is not the correct explanation of A.
Both A and R are true, and R is the correct explanation of A.
A is false, but R is true.
A is true, but R is false.
Correct answer:B
Standard Method
Given: Assertion: Butan-1-ol has a higher boiling point than ethoxyethane.
Find: Whether the assertion and reason are true, and whether the reason correctly explains the assertion.
Butan-1-ol contains an -OH group, allowing it to form hydrogen bonds, which increase intermolecular forces and raise the boiling point.
Ethoxyethane (ether) cannot form hydrogen bonds due to the lack of an -OH group, resulting in weaker intermolecular forces and a lower boiling point.
Hydrogen bonding is the primary reason for the stronger association of molecules in butan-1-ol compared to ethoxyethane.
Thus, both A and R are true, and R is the correct explanation of A. Therefore, the correct option is B.
Assuming ethers and alcohols have similar boiling points just because both contain oxygen is incorrect. The key difference is that alcohols with an -OH group can form intermolecular hydrogen bonding, whereas ethers cannot do so among their own molecules. Compare intermolecular forces, not only molecular formula or presence of oxygen.
Confusing hydrogen bond acceptance with hydrogen bond donation is a common mistake. Ethoxyethane can act as a hydrogen bond acceptor, but it lacks an O-H bond and therefore cannot form the same extensive intermolecular hydrogen bonding as butan-1-ol. Check whether the molecule has a hydrogen directly bonded to oxygen.
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