When chlorine gas (Cl2) reacts with water (H2O), it undergoes a chemical reaction known as hydrolysis. The reaction between chlorine and water produces two main products: hypochlorous acid (HOCl) and hydrochloric acid (HCl).
The reaction can be represented by the following equation:
Cl2 + H2O → HOCl + HCl
In this reaction, chlorine gas dissolves in water, and the following chemical changes occur:
Formation of Hypochlorous Acid (HOCl): Chlorine gas reacts with water to form hypochlorous acid, which is a weak acid and a powerful disinfectant. Hypochlorous acid is responsible for the bactericidal properties of chlorine compounds.
Formation of Hydrochloric Acid (HCl): Chlorine gas also reacts with water to produce hydrochloric acid, a strong acid. Hydrochloric acid dissociates into hydrogen ions (H+) and chloride ions (Cl-) in water, contributing to the overall acidity of the solution.
The hydrolysis of chlorine gas in water is an important reaction in the context of water treatment and disinfection. Chlorine is commonly used as a disinfectant in the form of chlorine gas or chlorine compounds (such as sodium hypochlorite or calcium hypochlorite) to treat drinking water, swimming pools, and wastewater. The reaction with water allows chlorine to form hypochlorous acid, which effectively kills bacteria, viruses, and other pathogens, helping to ensure water safety and public health.