ionic componuds tend to have higher boiling points than covalent compounds . both ammonia NH3 and methane CH4 are covalent compounds but yet the boiling point of ammonia 130C is higher than methane. what might account for this difference

Question

please help thank you

Answer 1

CH4 is a symmetrical molecule and has no dipole moment. NH3 is not so it does have a dipole moment caused by the difference in electronegativity between H and N. As a result, NH3 molecules are attracted to each other with dipole-dipole intermolecular forces (actually hydrogen bonds but H bonding is a special case of dipole-dipole attraction); thus, it takes more energy to vaporize NH3 than it does CH4.