Arrange the following in decreasing order of their boiling point:

Choose the correct options from the following

I > II > III

The correct answer is 1.      I > II > III.

The boiling points of the three substances are as follows:

As you can see, ethanol has the highest boiling point, followed by diethyl ether, and then propane. This is because ethanol has the strongest intermolecular forces, due to hydrogen bonding. Diethyl ether has weaker intermolecular forces due to dipole-dipole interactions, and propane has the weakest intermolecular forces due to London dispersion forces.