Development of the Modern Freezer. Bacteria are usually the cause of food decay, but they can't grow as well or at all in freezing temperatures, which are at 32 degrees Fahrenheit (0 degrees Celsius) or lower.
HF- polar molecule: dipole-dipole forces. There are also dispersion forces and H bond between HF. BF3- nonpolar: dispersion forces. Ar- Dispersion forces between Ar atoms.
HF is the only molecule that contains an H-F bond. There are many molecules that contain H-O or H-N bonds. It is not just the H-O and H-N bonds that make these molecules polar. The unbonded pairs of electrons on the nitrogen or oxygen atoms also contribute to the polarity of the molecules.