A chemist compares two constitutional isomers sharing the molecular formula C2H6O: ethanol (CH3CH2OH) and dimethyl ether (CH3OCH3). Under standard atmospheric pressure, pure ethanol boils at 78 °C, whereas pure dimethyl ether boils at -24 °C despite having identical molar masses. Based on their molecular structures and intermolecular forces, which statement correctly explains this difference in boiling points?
- A) Ethanol molecules experience substantially stronger London dispersion forces because ethanol possesses a larger total number of electrons than dimethyl ether.
- B) Ethanol molecules form intermolecular hydrogen bonds via their O–H groups, demanding much more thermal energy to separate than the dipole–dipole attractions in dimethyl ether.
- C) Dimethyl ether cannot participate in hydrogen bonding because its central oxygen atom lacks non-bonding valence electron pairs.
- D) The intramolecular covalent bonds within ethanol are much stronger than those within dimethyl ether, requiring higher temperatures to break during boiling.
