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

please help thank you

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.

The difference in boiling points between ammonia (NH3) and methane (CH4) can be attributed to a concept called hydrogen bonding. While both ammonia and methane are covalent compounds, ammonia molecules have stronger intermolecular forces due to the presence of hydrogen bonding, which results in a higher boiling point.

To understand why ammonia has a higher boiling point than methane, we need to consider the molecular structure and the nature of intermolecular forces. Both ammonia and methane consist of molecular units, with ammonia having one nitrogen atom (N) bonded to three hydrogen atoms (H), and methane having one carbon atom (C) bonded to four hydrogen atoms (H).

In methane, the carbon atom is bonded to hydrogen atoms through covalent bonds, resulting in a nonpolar molecule. The intermolecular forces in methane are relatively weak London dispersion forces, which arise due to temporary fluctuations in electron distribution, causing temporary polarization of the molecule.

In ammonia, however, the nitrogen atom forms a polar covalent bond with each hydrogen atom, creating a bent molecular structure. The nitrogen atom has a lone pair of electrons, which creates an area of partial negative charge. This partial negative charge on nitrogen can interact with the partial positive charges on hydrogen atoms of neighboring ammonia molecules, forming hydrogen bonds.

Hydrogen bonding is a stronger intermolecular force compared to London dispersion forces, as it involves the attraction between the positive hydrogen atom and the electronegative atom (in this case, nitrogen). This extra hydrogen bonding in ammonia contributes to the higher boiling point.

The strength of intermolecular forces affects the energy required to separate the molecules and change from a liquid to a gas phase. Ammonia's higher boiling point indicates that more energy is needed to overcome the hydrogen bonding between its molecules compared to methane's weaker London dispersion forces.

In summary, while both ammonia and methane are covalent compounds, ammonia has a higher boiling point due to the presence of stronger intermolecular hydrogen bonding forces between its polar molecules.