Question

Assertion (A): The boiling point of ethanol is higher than that of methoxymethane.
Reason (R): There is intramolecular hydrogen bonding in ethanol.

• A. Assertion (A) is true, but Reason (R) is false.
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Hydrogen bonding increases the boiling point of compounds as it requires more energy to break these bonds.

Answer 1

The Correct Option is A

To address this question, we will examine the provided assertion and reason.

Assertion (A):
The boiling point of ethanol surpasses that of methoxymethane.

Reason (R):
Ethanol demonstrates intramolecular hydrogen bonding.

1. Boiling Points of Ethanol and Methoxymethane:
Ethanol (C₂H₅OH) exhibits a higher boiling point than methoxymethane (CH₃OCH₃). This discrepancy is primarily attributable to the presence of hydrogen bonding in ethanol.

2. Hydrogen Bonding in Ethanol:
Ethanol forms intermolecular hydrogen bonds between the -OH group of one molecule and a hydrogen atom of another. These robust intermolecular forces necessitate greater energy input for breakage, leading to ethanol's elevated boiling point relative to methoxymethane.

3. Evaluation of Assertion (A):
The assertion that ethanol possesses a higher boiling point than methoxymethane is accurate. Methoxymethane, a simple ether, lacks hydrogen bonding capabilities, consequently exhibiting a lower boiling point than ethanol.

4. Evaluation of Reason (R):
The stated reason is not entirely accurate. While ethanol does engage in hydrogen bonding, it is intermolecular hydrogen bonding, not intramolecular, that influences its boiling point. Thus, the reason is incorrect.

5. Conclusion:
The assertion is correct, whereas the reason is incorrect. Ethanol's higher boiling point is a consequence of intermolecular hydrogen bonding, not intramolecular hydrogen bonding.

Final Answer:
The correct determination is that the assertion is true, but the reason is false.