Chlorine Gas

Brief Overview

Chlorine is a pale yellow-green gas which has atomic number 17. It is used in household products and generally used in industry. Chlorine is a reactive and also strong oxidizing agent. It has various properties, such as pungent, irritating odor, non-flammable, but will react explosively with other chemicals like ammonia and turpentine. In water treatment, chlorine is generally used as a disinfectant to kill harmful bacteria.

Manufacturing Process

Chlorine can be produced by the Chloralkali process which is the electrolysis of a sodium chloride solution. The co-products of the reaction are caustic soda (sodium hydroxide) and hydrogen gas (H2). Chlorine can also be produced by electrolyzing a potassium chloride solution, which produces hydrogen and caustic potash as co-products (potassium hydroxide). There are three industrial methods for extracting chlorine from chloride solutions using electrolysis, all of which follow the equations below:
For cathode: 2 H+ (aq) + 2 e− → H2 (g)
For anode: 2 Cl− (aq) → Cl2 (g) + 2 e−
The overall process can be written below:
 2 NaCl + 2 H2O → Cl2 + H2 + 2 NaOH 

Chemical Industry Chlorine gas is used in various chemical industries, including as an intermediate in the synthesis of various chemicals, including polyvinylchloride (PVC), pesticides, household cleaning products, and paper and textile bleach.

Water Treatment Chlorine compounds are commonly used for disinfecting drinking water, swimming pools, and in sewage treatment plants.

Other Uses Chlorine dioxide gas is used as a disinfectant for laboratory and manufacturing equipment and clean rooms.