Final answer:
The boiling points of dimethyl ether, ethanol, and propane increase with the strength of their intermolecular forces: propane with only dispersion forces has the lowest boiling point, followed by dimethyl ether with dipole-dipole interactions, and ethanol with hydrogen bonding has the highest.
Step-by-step explanation:
When considering molecular geometry and intermolecular forces (IMFs), the boiling points of dimethyl ether (CH3OCH3), ethanol (CH3CH2OH), and propane (CH3CH2CH3) can be explained. All three molecules have similar molar masses and shapes, so their dispersion forces are comparable. However, the type and strength of additional IMFs present in each compound significantly impact their boiling points.
Propane is nonpolar and exhibits only dispersion forces, leading to the lowest boiling point among the three. Dimethyl ether, while polar, has both dispersion forces and dipole-dipole interactions, resulting in a higher boiling point than propane. Ethanol features an -OH group, allowing it to engage in hydrogen bonding, the strongest type of IMF among the three compounds, leading to the highest boiling point.
The correct order of increasing boiling points for these compounds is propane < dimethyl ether < ethanol, corresponding to the strengths of their respective IMFs.
The boiling points of compounds can be determined by considering their intermolecular forces (IMFs). In this case, we need to compare dimethyl ether (CH3OCH3), ethanol (CH3CH2OH), and propane (CH3CH2CH3) in terms of increasing boiling points.
The VSEPR-predicted shapes of these compounds are similar, as are their molar masses. Therefore, they will exhibit similar dispersion forces. Propane, being nonpolar, only exhibits dispersion forces. Dimethyl ether is polar, so it experiences both dispersion forces and dipole-dipole attractions. Ethanol has an -OH group, which allows it to experience the stronger dipole-dipole attraction known as hydrogen bonding.
Based on the strength of their IMFs, the order of increasing boiling points is: propane < dimethyl ether < ethanol.