NH3 or CH4 (I think it is NH3 because of hydrogen bonds.)

CO2 or NO2 (I think it is NO2 because it is polar.)

CS2 or CO2 (I think this one is the same but I am not sure.)

I would just like to know if I am correct in my answers and my methods to determining the highest boiling point.

I under stand the first one.

The second one I think is NO2 because it is slightly more polar and weighs more.

I think the CS2 has a higher boiling point than the CO2 because the CS2 weighs more.

Is my method to determining the highest boiling point correct?