Hydrogen peroxide
A reactive oxygen species used as an oxidizer and antiseptic.
Hydrogen peroxide is a chemical compound with the formula H2O2. In its pure form, it is a very pale blue liquid, though at lower concentrations it appears colorless. It is used as an oxidizer, bleaching agent, and antiseptic, and in higher concentrations as a rocket propellant.
- formula
- H2O2
- melting_point
- -0.43 °C (pure)
- density
- 1.45 g/cm³ (pure)
- solubility
- Miscible in water
- common_uses
- Oxidizer, bleaching agent, antiseptic
Lore & Background
An improved version of Thénard's process used hydrochloric acid and sulfuric acid to precipitate barium sulfate. The anthraquinone process, developed during the 1930s by IG Farben, remains the dominant manufacturing method.
Reader's Guide
Hydrogen peroxide is significant as the simplest peroxide and a reactive oxygen species. It decomposes slowly into water and oxygen when exposed to light, and rapidly in the presence of organic compounds. Its strong hydrogen bonding gives it higher viscosity than water. In rocketry, concentrated hydrogen peroxide has been used as both a monopropellant and an oxidizer. The molecule is chiral, being the smallest and simplest molecule to exhibit enantiomerism, which has been proposed as a factor in the origin of homochirality in an RNA world.
Did You Know?
- Hydrogen peroxide is the smallest and simplest molecule to exhibit enantiomerism.
- Its boiling point is approximately 50 °C higher than that of water, but it can undergo explosive thermal decomposition if heated to that temperature.
- Sea water contains 0.5 to 14 μg/L of hydrogen peroxide, and freshwater contains 1 to 30 μg/L.
Frequently Asked Questions
What are Hydrogen peroxide's powers and role?
It acts as a versatile oxidizing agent, a bleaching chemical, and a topical antiseptic for minor wounds. At higher concentrations it also serves as a rocket propellant, releasing a large burst of energy when it breaks down.
How does Hydrogen peroxide's story end?
Its natural fate is decomposition: it slowly (or rapidly, with a catalyst) splits into ordinary water and molecular oxygen gas. This breakdown is actually what makes it useful as a propellant and what causes the familiar fizzing on a scraped knee.
Why is Hydrogen peroxide important?
It bridges everyday medicine (wound cleaning, hair bleaching) and high-performance engineering (rocketry, industrial oxidation), making it one of the most broadly applied reactive oxygen species. Its ability to donate an oxygen atom to other molecules underpins a huge range of chemical and biological processes.
More in Chemistry 25-37
Elsewhere in the Chemistry universe
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record