Hydrogen Peroxide

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The main ingredient in hair bleach, it bleaches hair by breaking down melanin when it oxidizes. Always do a patch test when using hair color containing it, as it can cause chemical burns and/or allergic reactions.

Hydrogen Peroxide (Wikipedia)
Hydrogen peroxide
Structural formula of hydrogen peroxide
Ball-and-stick model of the hydrogen peroxide molecule
IUPAC name
hydrogen peroxide
Other names
7722-84-1 YesY
ChEBI CHEBI:16240 YesY
ChemSpider 763 YesY
EC Number 231-765-0
Jmol 3D image Interactive graph
KEGG D00008 YesY
PubChem 784
RTECS number MX0900000 (>90% soln.)
MX0887000 (>30% soln.)
UN number 2015 (>60% soln.)
2014 (20–60% soln.)
2984 (8–20% soln.)
Molar mass 34.0147 g/mol
Appearance Very light blue color; colorless in solution
Odor slightly sharp
Density 1.11 g/cm3 (20 °C, 30% (w/w) solution )
1.450 g/cm3 (20 °C, pure)
Melting point −0.43 °C (31.23 °F; 272.72 K)
Boiling point 150.2 °C (302.4 °F; 423.3 K) (decomposes)
Solubility soluble in ether, alcohol
insoluble in petroleum ether
Vapor pressure 5 mmHg (30 °C)
Acidity (pKa) 11.75
Viscosity 1.245 cP (20 °C)
2.26 D
1.267 J/(g·K) (gas)
2.619 J/(g·K) (liquid)
−187.80 kJ/mol
A01AB02 (WHO) D08AX01, S02AA06
Safety data sheet ICSC 0164 (>60% soln.)
Hazard O.svgOxidant (O)
Hazard C.svgCorrosive (C)
Hazard X.svgHarmful (Xn)
R-phrases R5, R8, R20/22, R35
S-phrases (S1/2), S17, S26, S28, S36/37/39, S45
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gasReactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorusSpecial hazard OX: Oxidizer. E.g., potassium perchlorateNFPA 704 four-colored diamond
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
1518 mg/kg[citation needed]
2000 mg/kg (oral, mouse)
1418 ppm (rat, 4 hr)
227 ppm (mouse)
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 1 ppm (1.4 mg/m3)
REL (Recommended)
TWA 1 ppm (1.4 mg/m3)
IDLH (Immediate danger)
75 ppm
Related compounds
Related compounds
Hydrogen disulfide
Dioxygen difluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Hydrogen peroxide is a chemical compound with the formula H
. In its pure form, it is a colourless liquid, slightly more viscous than water; however, for safety reasons it is normally used as an aqueous solution. Hydrogen peroxide is the simplest peroxide (a compound with an oxygen–oxygen single bond) and finds use as a strong oxidizer, bleaching agent and disinfectant. Concentrated hydrogen peroxide, or "high-test peroxide", is a reactive oxygen species and has been used as a propellant in rocketry.

Hydrogen peroxide is often described as being "water but with one more oxygen atom", a description that can give the incorrect impression of significant chemical similarity between the two compounds. While they have a similar melting point and appearance, pure hydrogen peroxide will explode if heated to boiling, will cause serious contact burns to the skin and can set materials alight on contact. For these reasons it is usually handled as a dilute solution (household grades are typically 3–6% in the U.S. and somewhat higher in Europe). Its chemistry is dominated by the nature of its unstable peroxide bond.

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