Boiling point and intermolecular forces?

Question

I am trying to understand intermolecular forces a bit better and how they are related to boiling points. Which of the following should have the highest boiling point and why?
- CF4
- CCl 4
- CBr4
- Cl4
- CH4
Thanks!

Answer 1

The main deteminant in a boiling point is the intermolecular forces. In simple terms, how hard do you have to pull the molecules apart to turn a liquid into a gas. The harder to pull, the higher the boiling point.

Hydrogen bonding is the strongest of the intermolecular forces, but none of your examples have that type of bond (water does). All of your molecules are symmetrical, so even dipole forces do not have a role here.

So the next best analysis is that the highest molecular mass will have the highest boiling point. CI4 has the highest mass and should have the highest BP of the group.