Liquid nitrogen is one of the most widely used gases in the industrial, medical, and scientific worlds, and is used in many processes and applications due to its unique properties at very low temperatures.
In its liquid state, this gas appears bright blue. This color is due to the absorption of certain wavelengths of light by its molecules. At ordinary temperatures and pressures, oxygen is naturally colorless and odorless.
Carbon dioxide is a colorless gas or a colorless, cryogenic liquid. At low concentrations, the gas is odorless. At higher concentrations, it has a pungent, acidic odor. It will act as an asphyxiant and irritant. Carbon dioxide is a potent brain relaxant.
Argon is inert in both its gaseous and liquid states, and no actual compounds containing argon have been identified. Since argon gas absorbs a significant amount of heat when it evaporates, it is an excellent refrigerant.
