Question

In comparison to molecules that interact by London dispersion forces only, the melting point of similar-sized molecules forming hydrogen bonds would most likely be
about the same.
unpredictable.
lower.
higher.

Answer 1

The answer is higher.

You should know that the London dispersion force is the weakest intermolercular attractive force while the hydrogen bonds form a high attractive intermolecular force, so you have to expect that in molecules forming hydrogen bonds the molecules will be more attached to each other than in similar-sized molecules that interact by London dispersion forces only, which takes you to conclude that the melting point of the molecules forming hydrogen bonds will be higher.