Hydrogen chloride is colorless, with a melting point of -114.2 degrees and a boiling point of -85 degrees. It does not burn in the air and is thermally stable. It decomposes only at about 1500 C. It has a choking odor, has a strong irritation to the upper respiratory tract, and is corrosive to the eyes, skin and mucous membranes. Its density is greater than air. Its aqueous solution is hydrochloric acid. Concentrated hydrochloric acid is volatile. Hydrogen chloride is a corrosive, non-combustible gas that does not react with water but is easily soluble in water. The air often exists in the form of hydrochloric acid smoke. Soluble in ethanol and ether, as well as various other organics; soluble in water, at 25 C and 1 atmosphere, 1 volume of water can dissolve 503 volumes of hydrogen chloride gas.