AIIMS2001ChemistryChemical Bonding and Molecular Structure
Assertion : CH ₃ OCH ₃ and C ₂ H ₅ OH has comparable molecular weight but boiling point of C ₂ H ₅ OH is more than dimethyl ether. Reason : C ₂ H ₅ OH forms intermolecular Hbonding while CH ₃ OCH ₃ forms intramolecular H -bonding.
Options
- AIf both Assertion and Reason are true and Reason is the correct explanation of Assertion.
- BIf both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
- CIf Assertion is true but Reason is false.
- DIf Assertion is false but Reason is true.
Correct answer
C. If Assertion is true but Reason is false.
Step-by-step solution
Due to the presence of hydroxyl group (- OH ) , there is extensive hydrogen bonding between the ethanol molecules ( C ₂ H ₅ OH ) . But there is no such hydrogen bonding in dimethyl ether (due to absence of -OH group). So boiling point of dimethyl ether is much lower than ethanol.