VIAS Encyclopedia: Hydrogen Peroxide

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Home Chemistry Inorganic Compounds Hydrogen Peroxide	Index



Hydrogen Peroxide Hydrogen peroxide (H₂O₂) is a viscous liquid (mp.: -0.89°C, bp.: 152.1°C, density: 1.448 g/cm³ at 20°C) that has strong oxidizing properties. It is commonly used (in concentrations typically around 5%) to bleach human hair, hence the phrases "peroxide blonde" and "bottle blonde". It burns the skin upon contact in sufficient concentration. In lower concentrations (3%), it is used medically for cleaning wounds and removing dead tissue. However, recent studies have indicated that hydrogen peroxide is toxic to new cells and is therefore not recommended for wound care. The same solution is often used by medical professionals to clean blood from cloth and equipment. H₂O₂ is produced by a combination of electrolysis of sulfuric acid and subsequent hydrolysis of the resulting peroxo-disulfuric acid: 2 H₂SO₄ H₂S₂O₈ + H₂ H₂S₂O₈ + 2 H₂O H₂O₂ 2 H₂SO₄ 2 H₂O H₂O₂ + H₂ Hydrogen peroxide decomposes exothermically into water and oxygen gas (46.87 kcal/mol). However, at room temperature the rate of decomposition is very low, so that pure H₂O₂ is stable (metastable). Catalysts (like pulverized silver, gold, platinum, manganese dioxed, iron and copper salts, alkali salts, dust, activated carbon, etc.) dramatically increase the rate of decomposition. High concentrations of H₂O₂ may lead to explosions when it comes into contact with catalysts. H₂O₂ may be stabilized by adding phosphoric acid, sodium diphosphate, uric acid, or barbituric acid. Pure H₂O₂ without any stabilizers can only be stored in glass bottles which are coated with paraffin way, or in pure aluminum (better than 99.9 %) bottles.
Home Chemistry Inorganic Compounds Hydrogen Peroxide

Last Update: 2004-11-27