Predict Boiling Points of Molecules: CH_{3}F, C_{2}H_{6}, CH_{3}OH, C_{2}H_{4}

[temaire]

Homework Statement

For the following molecules, predict the order of their boiling points from highest to lowest.

1. CH_{3}F
2. C_{2}H_{6}
3. CH_{3}OH
4. C_{2}H_{4}

The Attempt at a Solution

I think the answer is 3 4 2 1. I put 3 first because it is an alcohol and has hydrogen bonding. I put 4 second because it has a double bond. I put 2 third because although it has the same amount of electrons as CH_{3}F it is a larger molecule. Am I correct?

 

[war485]

I agree that methanol has the highest boiling point. As for the other 3 choices, rethink them. Why else (besides the extra small weight) makes the alkene have a higher boiling point? Compare that to electronegativity. Which factor's more important?