The short answer to this question is that while hydrogen peroxide is a type of bleach, not all bleach products have hydrogen peroxide as the active ingredient. For example, the bleach you use for laundry can be classified into two categories: a chlorine-based bleach and an oxygen-based (peroxide-based) bleach. Both remove stains and kill microorganisms through oxidation-reduction reactions. However, oxygen-based bleach products such as hydrogen peroxide are not as strong as the chlorine-based bleach products, making them gentler to fabrics. Cottons and wool fabrics can weaken and eventually be damaged by chlorine-based bleach products. Continue reading to find out more about the difference between hydrogen peroxide and bleach.What is hydrogen peroxide?Hydrogen peroxide (H2O2) is a chemical compound that’s widely used as a weak oxidising acid and as a component in cleaning products. It’s an inorganic peroxide that consists of two hydroxy groups. These groups are connected by a covalent oxygen-oxygen single bond. Hydrogen peroxide is mostly a clear and colourless liquid, although it can appear pale blue in its pure form.Chemical composition and propertiesHydrogen peroxide is a relatively unstable compound. It readily decomposes to water and oxygen when exposed to air or when poured on rough surfaces. Chemically, a molecule of hydrogen peroxide is made up of two hydrogen and two oxygen atoms. The single oxygen-oxygen bond is weak, which makes the compound unstable. When hydrogen peroxide decomposes, it releases heat energy.Uses of hydrogen peroxideHydrogen peroxide has a wide range of uses:Household applications as a cleaning agent for surfaces like chopping boardsMedical-dental uses such as wound disinfectant and as a mouthwashBeauty industry in hair dyesIndustrial uses such as being a bleaching agent for pulp and fabricsBleach is used in the industrial manufacture of paperWhat is bleach?A bleach is any substance capable of chemically removing colours and killing microorganisms through oxidation-reduction reactions. In the case of removing colours or stains, bleach breaks the molecular bonds of chromophores (molecules that absorb and emit light at specific wavelengths). In the process, the specific wavelengths of light are not anymore absorbed or emitted in certain ways. Bleach kills microorganisms by stripping away the electrons of their protective membranes, which results in water and other internal components leaking.Chemical composition and propertiesThe chemical compositions of bleach products vary depending on their active ingredient, which can either be chlorine-based or oxygen or peroxide-based compounds. Examples of chlorine-based bleaches include sodium hypochlorite (NaClO), while examples of peroxide-based bleaches include hydrogen peroxide itself (H2O2) and sodium percarbonate (Na2H3CO6). Regardless of the type of bleach, it works in the same principle of oxidation–reduction reaction. The bleach acts as an oxidising agent.Uses of bleachBleach is widely used as a laundry cleaner, removing stains from fabrics. Bleaches also have important applications in medicine, particularly in disinfecting medical instruments and surfaces in hospitals and in clinics. The industrial applications of bleaches are also numerous, such as in paper manufacturing and textile manufacturing.Is hydrogen peroxide the same as bleach? As we mentioned earlier, hydrogen peroxide is a type of bleach, but not all bleaches have hydrogen peroxide as the active ingredient. In fact, hydrogen peroxide is just among the many other examples of peroxide-based bleaches.Chemical differencesSodium hypochlorite is the most common active ingredient used in bleach products. This is a chlorine-based type of bleach that typically releases either chlorate or oxygen depending on the conditions.If the sodium hypochlorite solution is subjected to high temperatures, it may release oxygen. See the balanced equation below:2 NaOCl(aq) → 2 NaCl(aq) + O2(g)Meanwhile, sodium hypochlorite solution may also auto oxidise into chloride and chlorate at room temperature. See the ionic equation below. When this happens, the chlorate acts as the oxidising agent.3 ClO−+ H+ → HClO3 + 2 Cl−On the other hand, hydrogen peroxide is the most common example of peroxide-based bleach. It simply decomposes into water and oxygen.2 H2O2 → 2 H2O + O2Effectiveness in cleaning and disinfectionChlorine-based bleaches are typically more effective than peroxide-based bleaches in terms of cleaning effectiveness and disinfection. The main reason for this is the fact that chlorine has a higher reduction potential (the capacity to gain electrons) than oxygen. While a substance such as chromophore is being oxidised or stripped away of electrons, the oxidising agent is being reduced. Hence, it’s called oxidation-reduction reaction, or redox. What are the safety guidelines for using these chemicals?Bleaches are toxic and can damage your skin as well as your mucus membrane. The fumes can irritate the air passage and lungs. You must read the safety labels to familiarise yourself with proper first aid and safety measures to take in the event you have an accident while handling bleach.Proper handling and storageAlways wear protective gear when you’re handling noxious chemicals such as sodium hypochlorite. For example, you should at least wear rubber gloves when using it as a cleaning agent. While we wouldn’t advise it, you might be okay to handle hydrogen peroxide without gloves – just make sure that you don’t get any of it on your eyes. These types of chemicals must always be stored in sealed containers and away from the reach of children and animals.Personal protective equipment (PPE)Basic PPE for handling noxious and toxic bleaches should include rubber gloves, face mask or respirator, goggles, and protective apron. The type of PPE will largely depend on the type and concentration of bleach you are handling.If you’re handling bleach in the workplace, make sure you follow the health and safety guidelines on the chemical’s Safety Data Sheet.Emergency procedures for exposureIf you’re exposed to bleach, immediately wash the affected area. Remove clothing if necessary. If ingested, follow relevant first aid procedures and call paramedics.ConclusionHydrogen peroxide is a type of bleach. However, not all bleaches have hydrogen peroxide as the active ingredient. There are other classes and specific examples of bleaches. Hydrogen peroxide has a wide range of applications, which include household, medical, dental, cosmetic, and industrial applications.
