The main difference between hypochlorite and hypochlorous acid is that hypochlorite is the anionic form of chlorine with a negative charge (ClO−), while hypochlorous acid is the weak acid form of chlorine (HOCl) that is more effective as a disinfectant due to its ability to penetrate cell walls.
Both hypochlorite and hypochlorous acid are composed of chlorine (Cl) atoms combined with oxygen (O) and hydrogen (H) atoms. Both forms are effective disinfectants.
Key Areas Covered
1. What is Hypochlorite (ClO−)
– Definition, Properties
2. What is Hypochlorous Acid (HOCl)
– Definition, Properties
3. Similarities Between Hypochlorite and Hypochlorous Acid
– Outline of Common Features
4. Difference Between Hypochlorite and Hypochlorous Acid
– Comparison of Key Differences
ClO−, HOCl, Hypochlorite, Hypochlorous Acid
What is Hypochlorite
Hypochlorite refers to the anionic (negatively charged) form of chlorine, often represented as ClO−. It is a chemical compound that contains chlorine and oxygen atoms. Hypochlorite compounds are commonly used as disinfectants, bleaching agents, and sanitizers due to their antimicrobial properties. They are often found in household bleach and various cleaning products.
One well-known example of a hypochlorite compound is sodium hypochlorite (NaClO), which is a key component of household bleach. Sodium hypochlorite solutions are used for disinfecting surfaces, cleaning, and whitening fabrics. Another example is calcium hypochlorite (Ca(ClO)2), which is used as a disinfectant and water treatment agent, especially for swimming pools and drinking water.
Hypochlorite compounds release hypochlorous acid (HOCl) when mixed with water, and this acid contributes to their disinfecting and antimicrobial properties. However, it’s important to handle hypochlorite compounds with care, as they can be irritating to the skin and eyes, and their use should be in accordance with recommended guidelines and precautions.
What is Hypochlorous Acid
Hypochlorous acid (HOCl) is a weak acid that arises from the reaction between chlorine (Cl₂) and water (H₂O). This reaction is reversible, symbolized by the equilibrium equation:
Cl₂ + H₂O ⇌ HOCl + HCl
Here, chlorine gas combines with water to yield hypochlorous acid and hydrochloric acid. HOCl exists in equilibrium with its conjugate base, the hypochlorite ion (ClO⁻):
HOCl ⇌ ClO⁻ + H⁺
The balance between hypochlorous acid and hypochlorite ions depends on the solution’s pH level. At lower pH values, hypochlorous acid dominates, while higher pH levels favor the hypochlorite ion. This pH-dependent equilibrium is pivotal in understanding hypochlorous acid’s disinfectant properties.
Hypochlorous acid’s potent disinfection capabilities have made it essential in various industries and contexts. It is extensively used in healthcare for disinfecting surfaces, wound care, and sterilizing medical equipment. In the food sector, it ensures safety by eliminating pathogens on surfaces and produce. Hypochlorous acid is a cornerstone of water treatment, effectively purifying drinking water and maintaining pool and wastewater hygiene.
Hypochlorite and Hypochlorous Acid
- Both hypochlorite and hypochlorous acid are composed of chlorine (Cl) atoms combined with oxygen (O) and hydrogen (H) atoms.
- In both compounds, chlorine is present in the +1 oxidation state.
- Both compounds have oxidizing properties, meaning they can donate oxygen atoms or accept electrons during chemical reactions. This property is why they are effective at killing microorganisms and breaking down organic matter.
- They are effective disinfectants. They are used to kill bacteria, viruses, and other pathogens by disrupting their cellular structures and functions.
Difference Between Hypochlorite and Hypochlorous Acid
Hypochlorite is an anionic form of chlorine represented as ClO− while hypochlorous acid is a weak acid with the chemical formula HOCl.
While hypochlorite exists as an anion, giving it an alkaline nature, hypochlorous acid is a weak acid, leading to a slightly acidic character.
Hypochlorite’s antimicrobial action is relatively slower, and it is more effective at higher pH levels. However, hypochlorous acid exhibits rapid and effective antimicrobial action, even at lower pH levels.
Use in Disinfection
Moreover, hypochlorite is used in some disinfecting products, bleach, and pool sanitation, whereas hypochlorous acid finds extensive use in medical applications, food safety, water treatment, and surface disinfection.
Hypochlorite can potentially cause more irritation and harmful effects due to its high pH nature. However, hypochlorous acid generally has lower toxicity and is less prone to causing irritation.
Hypochlorite is less stable in storage and tends to lose potency over time, whereas hypochlorous acid is more stable and less prone to losing potency, making it more suitable for storage.
While hypochlorite solutions have a strong and distinctive odor, hypochlorous acid solutions have a milder and less pungent odor.
The main difference between hypochlorite and hypochlorous acid is that hypochlorite is the anionic form of chlorine with a negative charge (ClO−), while hypochlorous acid is the weak acid form of chlorine (HOCl) that is more effective as a disinfectant due to its ability to penetrate cell walls. Hypochlorite is commonly used in disinfecting products and pool sanitation, while hypochlorous acid finds broader applications in medical settings, food safety, water treatment, and surface disinfection.
1. “Hypochlorit-Ion” By NEUROtiker ⇌ – Own work (Public Domain) via Commons Wikimedia
2. “Hypochlorous Acid as a Potential Wound Care Agent” By Wang L, Bassiri M, Najafi R – Journal of Burns and Wounds. 2007;6:e5. (CC BY 4.0) via Commons Wikimedia