Final answer:
Polar bonds occur in molecules like HCl, CH2O, NH3, CHCl3, BCl3, CCl4, PF5, and SF6 due to differing electronegativities. HCl, CH2O, NH3, and CHCl3 are polar molecules because they have a net dipole moment from their asymmetric shapes. BCl3, CCl4, PF5, and SF6, despite having polar bonds, are nonpolar molecules as their symmetrical geometry leads to the cancellation of dipole moments.
Step-by-step explanation:
To determine whether a molecule has polar bonds and if the molecule itself is polar, one must consider the electronegativity differences between atoms and the molecule's geometry. Molecules with polar bonds include HCl, CH2O, NH3, and CHCl3 because they have atoms with different electronegativities. However, whether the molecule is polar or nonpolar depends on whether these bond dipole moments cancel out. This is influenced by the molecule's shape or geometry.
Molecules like BCl3, CCl4, PF5, and SF6 also have polar bonds due to differences in electronegativity, but they are nonpolar molecules since their symmetrical geometry allows the bond dipoles to cancel each other out. In contrast, HCl, CH2O, NH3, and CHCl3 do not have symmetrical shapes, resulting in a net dipole moment and making them polar molecules.