Chlorine reacts with water to produce a mixture of two acids: hydrochloric acid (HCl) and hypochlorous acid (HClO). This reaction is fundamental in many applications, particularly in water purification.
The Chemical Process
When chlorine gas (Cl₂) dissolves in water (H₂O), it undergoes a disproportionation reaction. This means that the chlorine atoms are both oxidized and reduced. The reaction can be represented by the following equilibrium equation:
Cl₂(g) + H₂O(l) ⇌ HCl(aq) + HClO(aq)
- Reactants:
- Chlorine gas (Cl₂)
- Water (H₂O)
- Products:
- Hydrochloric acid (HCl)
- Chloric acid (HClO), also known as hypochlorous acid
According to the reference, When chlorine reacts with water, it forms a mixture of hydrochloric acid, HCl, and chloric acid, HClO. The reference further clarifies that Chloric acid is also known as hypochlorous acid.
Understanding the Products
Let's look at the two acids formed:
- Hydrochloric Acid (HCl): A strong acid that dissociates into hydrogen ions (H⁺) and chloride ions (Cl⁻) in water. It contributes to the acidity of the solution.
- Hypochlorous Acid (HClO): A weak acid that is the primary active agent in many chlorine-based disinfectants.
The Significance of Hypochlorous Acid (HClO)
Hypochlorous acid is the key player in the disinfecting properties of chlorinated water. As stated in the reference, It is a powerful oxidising agent that kills all sorts of bacteria and viruses, from common colds to cholera.
Here's why HClO is effective:
- Oxidizing Power: It disrupts the cell walls and internal structures of microorganisms through oxidation.
- Penetration: Being a neutral molecule, HClO can easily penetrate the cell membranes of bacteria and viruses.
- Disinfection: Its ability to kill a wide range of pathogens makes chlorine a common and effective method for disinfecting drinking water, swimming pools, and wastewater.
| Component | Chemical Formula | Description | Primary Role in Solution |
|---|---|---|---|
| Chlorine Gas | Cl₂ | The starting reactant. | Dissolves and reacts with water. |
| Water | H₂O | The solvent and reactant. | Medium for the reaction. |
| Hydrochloric Acid | HCl | A strong acid product. | Contributes to acidity. |
| Hypochlorous Acid | HClO | A weak acid product, also called Chloric acid (per the reference). | Powerful Oxidising Agent, Disinfectant. |
The reaction between chlorine and water is crucial for public health, providing a simple yet effective way to ensure water safety by leveraging the powerful oxidizing action of hypochlorous acid.
