bottle says it contains potassium permanganate.
Potassium permanganate
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Potassium permanganate
General
Other names Potassium manganate(VII)
Molecular formula KMnO4
Molar mass 158.04 g/mol
Appearance purple solid
CAS number [7722-64-7]
Properties
Density and phase 2.703 g/cm3, solid
Solubility in water 6.38 g/100 ml (20 ‹C)
Melting point 270 ‹C decomp.
Thermodynamic data
Standard enthalpy
of formation Æ'¢fH‹solid −813.4 kJ/mol
Standard molar entropy
S‹solid 171.7 J.K−1.mol−1
Hazards
EU classification Oxidant (O)
Harmful (Xn)
Dangerous for
the environment (N)
NFPA 704
R-phrases R8, R22, R50/53
S-phrases S2, S60, S61
Supplementary data page
Structure and
properties n, Æ'Ãr, etc.
Thermodynamic
data Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Regulatory data Flash point,
RTECS number, etc.
Related compounds
Other anions Potassium perrhenate
Other cations Sodium permanganate
Related compounds Potassium manganite
Potassium manganate
Manganese heptoxide
Except where noted otherwise, data are given for
materials in their standard state (at 25 ‹C, 100 kPa)
Infobox disclaimer and references
Potassium permanganate (KMnO4) is an inorganic chemical compound composed of potassium (K+) and permanganate (MnO4−) ions. Its IUPAC name is potassium manganate(VII) because its manganese (Mn) atom is in the +7 oxidation state. It is also known as "permanganate of potash", "Potassium Salt" and "Condy's crystals". The permanganate acts as a strong oxidizing agent. As a solid, it forms deep purple prisms. It is purple when dissolved in an aqueous solution. It has a sweet taste and is odorless.
Contents [hide]
1 History
2 Uses
2.1 The intriguing story of ozone and permanganate
3 Cautions
4 Common Usage
5 References
6 External links
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History
Potassium permanganate was discovered in 1659.
Early photographers used it as a component of flash powder.
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Uses
Potassium permanganate is used as an oxidizing agent in many different kinds of chemical reactions in a laboratory and in industry.[1] It is also used as a disinfectant and in deodorizers. It is used to treat some parasitic diseases of fish, and used in treatment of drinking water, as well as an antidote in phosphorus poisoning. In Africa many people have used it to soak vegetables and lettuce to neutralize any bacteria that may be present. It can be used as a reagent for the synthesis of many different kinds of chemical compounds. For example, a dilute solution of KMnO4 can convert an organic compound with a carbon-carbon double bond into a diol (glycol) compound. Stronger permanganate solutions can oxidize a methyl group on an aromatic ring to a carboxyl group. In analytical chemistry, a standardized aqueous solution of KMnO4 is sometimes used as an oxidizing titrant for redox titrations due to its deep purple color.
Deep purple-colored permanganate can be reduced to the faintly pink Mn+2 cation in an acidic solution, where Mn is in a +2 oxidation state. In an neutral solution, permanganate is only reduced to MnO2, a brown precipitate in which Mn is in a +4 oxidation state. In an alkaline solution, it is reduced to +6 oxidation state, giving K2MnO4.
KMnO4 can be used in an oxidative reaction with pseudoephedrine hydrochloride to produce methcathinone, a Schedule I drug in the United States. Consequently the DEA has restricted its use and sale by classifying it as a List I controlled precursor. Potassium permanganate is listed as a Table I precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances(Red list).
Dilute solutions are used as a mouthwash (0.25%), disinfectant for the hands (about 1%) and treatment for mild pompholyx dermatitis or fungal infections of the hands or feet.
In aqueous solution was used as together with T-Stoff (i.e. 80 % hydrogen peroxide) as propellant for the rocket plane Messerschmitt Me 163. In this usage, it is known as Z-Stoff. This combination of propellants is still used in torpedoes.
It is used as a reagent to determine the Kappa number of wood pulp.
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The intriguing story of ozone and permanganate
A curious reaction is observed when one adds concentrated sulfuric acid to potassium permanganate. Although no reaction may be apparent, the vapor over the mixture will ignite paper impregnated with alcohol. In principle (although not recommended!), this reaction could be used to produce rapid fire in a laboratory, requiring no matches or other ignition sources. Potassium permanganate and sulfuric acid react to produce some ozone, which has a high oxidising power and rapidly oxidises the alcohol, causing it to combust. An approximate equation for the ozone formation is shown below.
6 KMnO4 + 9 H2SO4 ¨ 6 MnSO4 + 3 K2SO4 + 9 H2O + 5 O3
The H2SO4/KMnO4 reaction can also produce the oily Mn2O7, which is unstable and can decompose explosively.
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Cautions
Solid KMnO4 is a very strong oxidizer, which when mixed with pure glycerine, will cause a highly exothermic chemical reaction to take place. Thermite is sometimes ignited using this reaction between KMnO4 and glycerin. This reaction would turn red hot as a spontaneous "combustion" which would melt a glass or other container holding the reacting contents and could ignite anything flammable nearby. A reaction of this sort could take place when solid KMnO4 is mixed with many kinds of organic materials. Aqueous solutions of KMnO4 are much less dangerous, especially when diluted. Mixing solid KMnO4 with concentrated sulfuric acid forms Mn2O7 which causes an explosion.[2] Also, it should never be left near petrol (gasoline) or any such readily oxidisible substance.
Potassium permanganate mixtures are very sensitive to moisture. For example, relatively pure powdered potassium permanganate + powdered sugar will ignite (but not explode) a few seconds after a drop of water is added.
Potassium permanganate stains the hand and clothing (as it is reduced to MnO2) and should be handled with care. Clothing stains may be washed away using acetic acid. Skin stains disappear within 48 hours. In addition, mixing solid KMnO4 with concentrated hydrochloric acid generates dangerous chlorine gas. [3]
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Common Usage
Potassium permanganate is often included in survival kits along with either glycerine or a glucose tablet for the purposes of making fire. The glucose tablet can be ground up, mixed with the potassium permanganate and caused to combust by applying friction. It can also be mixed with anti-freeze from a vehicle to produce flame, although this can be dangerous and should be done in a controlled manner ie dipping some paper into the anti-freeze and then adding a small amount of potassium permanganate. The ability to sterilise water and wounds is also advantageous and another reason for inclusion in a survival kit
