Chlorine gas is a yellow-green gas with a strong, pungent odor. It is a chemical element with the symbol Cl and atomic number 17. Chlorine is commonly used in water treatment to kill bacteria and other harmful microorganisms, making it essential for maintaining safe drinking water. It is also used in the production of various household cleaning products and disinfectants. In its natural state, chlorine is highly reactive and can form compounds with many elements. It is important to handle chlorine gas with care, as it can be toxic and cause respiratory issues if inhaled. Proper safety measures are necessary when working with this chemical.