# What intermolecular forces are present in CH_3OH?

Jun 23, 2018

Well, you got hydrogen bound to the VERY ELECTRONEGATIVE oxygen atom....

#### Explanation:

And in such a scenario where hydrogen is bound to a strongly electronegative element, hydrogen bonding is known to occur….a special case of bond polarity...

We could represent the dipoles as...

${H}_{3} C - \stackrel{{\delta}^{+}}{O} - \stackrel{{\delta}^{-}}{H}$

And in bulk solution, the molecular dipoles line up...and this is a SPECIAL case of dipole-dipole interaction, $\text{intermolecular hydrogen bonding}$, the which constitutes a POTENT intermolecular force, which elevates the melting and boiling points of the molecule.

And so we got normal boiling points of...

$C {H}_{4}$ ;-164 ""^@C.

${H}_{3} C - C {H}_{3}$ ;-89 ""^@C.

${H}_{3} C - O H$ ;+64.7 ""^@C.

${H}_{3} C - C {H}_{2} O H$ ;+78.5 ""^@C.

$H - O - H$ ;+100.0 ""^@C.

Of course, dispersion forces operate between all molecules...but these are not the same magnitude as intermolecular hydrogen bonding....