What is Chlorine gas?
Chlorine is a green yellow gas with a very pungent odour that is twice as dense as air. It is a chemical element belongs to the halogen group with the symbol Cl. It was discovered in 1770’s and soon became useful as a commercial agent.It is found easily in natural state. It should be handled carefully because it is poisonous at low concentrations. Chlorine is very harmful and been used as chemical weapons throughout history.
Other name – Molecular chlorine
|Molecular Weight/ Molar Mass||35.453 u|
|Boiling Point||-34.04 °C|
|Melting Point||-101.5 °C|
Chlorine gas Structure – Cl2
Physical Properties of Chlorine gas – Cl2
|Odour||Odour of bleach|
|Appearance||Yellow green gas|
|Vapour Pressure||85.3 psig|
|Solubility||Slightly soluble in water|
Chemical Properties of Chlorine gas – Cl2
- Chlorine reacts with organic compounds and ammonia to form chloro-organics or chloramines. Chloramines are part of the group of chlorine compounds that have disinfectant properties and show up as part of chlorine residue test.
- It acts as a reducing agent present in wastewater. These reactions are called chlorine demand. The reaction is as below.H2O + Cl2 → HCl + HClO
Uses of Chlorine gas – Cl2
- Chlorine gas was used by the Germans as a chemical weapon against the allied troops during the First World War.
- The most common use of chlorine in wastewater treatment is for disinfection.
- Used in odor control and in the control of filamentous organisms in the activated sludge process.
- Despite of all these it is used for preventing the spread of waterborne disease and the most common means of disinfection in use.