# Can the normal boiling points of alkanes versus alcohols be related to their structural properties?

Jun 1, 2017

Compare the normal boiling point of methanol, $64.7$ ""^@C, and that of ethanol, $78.2$ ""^@C, WITH THAT of methane, $- 164$ ""^@C, and ethane, $- 89$ ""^@C.
The difference in volatility may be attributed to intermolecular hydrogen bonding. Hydrogen is bound to a strongly electronegative element, i.e. to give $R - \stackrel{\delta -}{O} - \stackrel{\delta +}{H}$, and in solution, the dipoles line up to give a strong attractive between molecules. As the hydrocarbyl chain grows, the importance of hydrogen bonding becomes less dominant. Ethanol and methanol are each infinitely miscible in water, which also possesses strong hydrogen bonding.