The molecules propanol and ethyl methyl ether $($below$)$ have the same molecular

formula but different normal boiling points, as shown. Why is this?

Both molecules are only able to undergo London dispersion forces, but propanol is

longer.

Ethyl methyl ether can undergo hydrogen bonding while propanol cannot. The

strongest intermolecular interactions that propanol can undergo are dipole$-$dipole

forces.

Propanol is able to undergo hydrogen bonding while ethyl methyl ether cannot.

The strongest intermolecular interactions that ethyl methyl ether can undergo are

dipole$-$dipole forces.

While both molecules are polar, ethyl methyl ether is more polar.