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.
Hydrogen fluoride is a chemical compound with the chemical formula HF. This colorless gas or liquid is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers (e.g. Teflon).F is widely used in the petrochemical industry and is a component of many superacids. Hydrogen fluoride boils near room temperature, while other hydrogen halides evaporate at much lower temperatures. Unlike other hydrogen halides, HF is lighter than air and diffuses relatively quickly through porous substances.