Answer:
In general terms, because (1) the carbon-oxygen and hydrogen-oxygen bonds in ethanol are much more polar than any of the bonds in propane; (2) the oxygen atom in ethanol can form hydrogen bonds with the hydrogen atoms in water, but there is not such possibility with propane; and (3) propane contains more carbon atoms per molecule than ethanol.
Step-by-step explanation:
In general terms, because (1) the carbon-oxygen and hydrogen-oxygen bonds in ethanol are much more polar than any of the bonds in propane; (2) the oxygen atom in ethanol can form hydrogen bonds with the hydrogen atoms in water, but there is not such possibility with propane; and (3) propane contains more carbon atoms per molecule than ethanol.