Question

Why are high heats of vaporization usually associated with high boiling temperature?

Answer 1

Well, let's consider what it really means to have a high "heat of vaporization".

Literally, it means you need a lot of heat to vaporize something (a liquid is the easiest starting point here).

Next, a "boiling temperature" (i.e. a boiling point) is literally the temperature at which something boils. (You know, like the `100^@ "C"` boiling point for pure water.)

You know that you need heat to increase the temperature.

The higher the boiling temperature, the more heat you had to have applied to get to that temperature.

Thus, a high heat of vaporization is normally required to get to a high boiling point, i.e. a high boiling temperature.