Question

Why is methanol a liquid and propane a gas at 298K?

a. Methanol has stronger intermolecular forces.
b. Methanol has a higher molecular weight.
c. Propane has stronger intermolecular forces.
d. Propane has a lower boiling point.

Answer 1

Methanol is a liquid and propane is a gas at 298K because methanol can participate in hydrogen bonding due to its hydroxyl group, resulting in a higher boiling point compared to propane, which only displays London dispersion forces.

Step-by-step explanation:

The reason methanol is a liquid and propane is a gas at 298K is due to the different intermolecular forces that act upon them. Methanol has the ability to engage in hydrogen bonding, a type of strong dipole-dipole interaction, due to the presence of its -OH (hydroxyl) group.

This bonding greatly increases the boiling point of methanol compared to propane, which can only exhibit relatively weak London dispersion forces because it is a nonpolar molecule. The boiling point of methanol (65 °C) is much higher than that of propane (-42.1 °C), indicating that more energy is needed to turn methanol into a gas, which is why it is a liquid at room temperature.