imagine replacing one H atom of a methane molecule, ch4, with another atom or group of atoms. Account for the order in the normal boiling points of the resulting compounds:CH4(-161 celsius); CH3Br(3.59 celsius); CH3F(-78 CELSIUS); CH3OH(65 CELSIUS).

Answer 1

CH4 is symmetrical and nonpolar, and as a result has low intramolecular attraction, and boils easily (i.e. at low temperature)

The other compounds are polar to varying degrees. The heaviness of
CH3Br molecules makes them harder to boil than CH3F.

I have no explanation for the high boiling point of CH3OH. There could be some intramolecular hydrogen bonding, as is the case with with water.