Properties of chlorine

Chlorine is relatively inexpensive because it is a coproduct of a major industry-production of chlorine and caustic (NaOH). Railroad tank cars carry liquid chlorine all over the U.S. This very dangerous chemical was used in combat in World War I; it is much heavier than air and collected in trenches to maim and kill. Dry chlorine attacks metals slowly, but moist chlorine is highly corrosive. It is moderately soluble in water: 7.3 g/L at 20 C and 1 atm.