Propanol has higher boiling point than propane Because of hydrogen bonding. The alcohol ends in a Hydrogen atom which can form a weak bond with the Oxygen atom on another alcohol molecule. These bonds make it harder for the molecules to separate in order for them to enter the gas phase. This raises the boiling point.

Introduction:

Propanol and propane are both organic compounds belonging to the alcohol and alkane functional groups, respectively. Despite having a similar molecular formula (C3H8O), propanol has a higher boiling point compared to propane. This difference in boiling points can be attributed to several factors, including intermolecular forces and molecular structure.

Intermolecular forces:

Intermolecular forces are attractive forces that exist between molecules. They play a crucial role in determining the physical properties of substances, such as boiling points. In the case of propanol and propane, the difference in boiling points can be primarily explained by the differences in the types and strengths of intermolecular forces present.

Hydrogen bonding:

Propanol contains a hydroxyl group (-OH), which allows for the formation of hydrogen bonds between propanol molecules. Hydrogen bonding is a particularly strong intermolecular force that occurs when a hydrogen atom is bonded to a highly electronegative atom (such as oxygen or nitrogen) and is attracted to a lone pair of electrons on another molecule. The presence of hydrogen bonding in propanol significantly increases its boiling point.

London dispersion forces:

On the other hand, propane lacks a hydroxyl group and does not have the ability to form hydrogen bonds. However, it still experiences London dispersion forces, which are relatively weak intermolecular forces that arise from temporary fluctuations in electron distribution within molecules. London dispersion forces increase with the size and shape of the molecules. Propanol has a larger and more complex molecular structure compared to propane, leading to stronger London dispersion forces.

Overall comparison:

Considering the intermolecular forces at play, propanol has both hydrogen bonding and London dispersion forces, while propane only has London dispersion forces. Since hydrogen bonding is stronger than London dispersion forces, propanol exhibits stronger intermolecular attractions, requiring more energy to break these forces and transition from the liquid to the gaseous phase.

Conclusion:

In summary, propanol has a higher boiling point than propane due to the presence of hydrogen bonding in addition to London dispersion forces. The ability of propanol to form hydrogen bonds significantly increases the strength of intermolecular attractions, requiring more energy to overcome these forces and vaporize the substance.