Question

For each of the following pairs of molecular substances, predict which member of the pair would have the lower boiling point.

O2
O3

SO2
O3

CH4
NH3

NH3
NF3

I'm not sure how exactly you do this, so any help would be great!

Answer 1

to predict boiling point intermolecular forces are required.
In the 1st pair O3 has higher molecular mass. So it has high attractive force. So high energy is needed to break bonds. therefore O3 has higher boiling point

2nd lower boiling point - O3

3rd one - NH3 has Hydrogen bonds. Hydrogen bonds are stronger than other inter molecular forces. So has High boiling points

4th - Both has hydrogen bonds.Main factor affecting hydrogen bond is the difference between electronegativity.
F has high electronegativity. So NF3 has high difference.So H bond is stronger. So NF3 has high boiling point.