Chloramine, also known as monochloramine, is a compound formed by the reaction of chlorine with ammonia in water. It is a type of disinfectant commonly used in water treatment to kill or control the growth of harmful microorganisms. Chloramine is typically used as an alternative to free chlorine because it produces fewer disinfection byproducts, such as trihalomethanes (THMs), which can be harmful to health.

The chemical formula for chloramine is NH2Cl, representing the combination of one ammonia molecule (NH3) and one chlorine atom (Cl).

Formation of Chloramine: Chloramine is formed when chlorine gas (Cl2) or hypochlorite (in the form of sodium hypochlorite or calcium hypochlorite) is added to water containing ammonia (NH3). The reaction is as follows:

Cl2 + NH3 → NH2Cl + HCl

Uses of Chloramine: Chloramine is primarily used in water treatment to disinfect drinking water and to control the growth of harmful microorganisms in water distribution systems. It provides a longer-lasting residual disinfectant compared to free chlorine, which helps maintain water quality as it moves through the distribution network.

Chloramine is also used in some swimming pools as a disinfectant, but it has some drawbacks in pool applications, such as reduced effectiveness against certain pathogens and potential eye and skin irritation.

Safety Considerations: Chloramine is generally considered safer than free chlorine, but it still requires careful handling. It can irritate the eyes, skin, and respiratory system, so proper precautions should be taken when working with or using chloramine solutions.

It’s important to note that chloramine can have adverse effects on some aquatic organisms, particularly fish and other aquatic life. Some cities that use chloramine as a disinfectant may provide guidance on handling tap water for aquariums and fish tanks.

As with any chemical used for water treatment, the concentration of chloramine in drinking water is carefully controlled to ensure it remains within safe limits for human consumption.