Potassium permanganate is soluble in acetone, water, pyridine, methanol and acetic acid. It is also readily soluble in inorganic solvents. It has a rich purple colour in concentrated solution and pink colour in diluted solution. Concentrated and dilute solutions of potassium permanganate. It is not combustible but supports combustion of other substances. Under normal conditions it is a highly stable compound but decomposes upon heating to form MnO 2 and liberates oxygen.
It is a strong oxidizing agent a compound that can easily transfer its oxygen to other substances forming a dark brown colored manganese dioxide MnO 2 which stains anything that is organic. It can readily accept electrons from other substances. It reacts violently with sulphuric acid resulting in an explosion. It reacts immediately with glycerol and simple alcohols producing flame and smoke.
In permanganate anion MnO 4 - the manganese atom is bonded with four oxygen atoms through three double bonds and one single bond. Its structure can be written as below. The crystal structure of solid KMnO 4 is orthorhombic. Each MnO 4 - structure is present in tetrahedral geometry. Most of the reactions with Potassium permanganate are redox reactions a chemical reaction in which one substance is oxidized and another is reduced.
KMnO 4 can oxidize many inorganic compounds. The medium of solution plays an important role in determining the products of reaction. In a neutral medium, MnO 2 forms a brown deposit. In the alkaline medium, MnO 4 2- is reduced.
On heating, permanganate crystals decompose to release oxygen. On diluting permanganate crystals in the presence of direct sunlight, oxygen is liberated. Other reactions of potassium permanganate are as follows:. With sulphuric acid:.
With hydrogen peroxide:. It can also oxidize carbon atoms that have double bonds in weak alkaline or neutral medium. It can oxidize aldehydes to form carboxylic acids. It oxidizes alcohols to form carbonyls.
It can also oxidize carbon atoms that have triple bonds to form diones. It oxidizes sugar to acids by breaking the carbon skeleton at double bonds.
Medical uses. Potassium permanganate acts as a disinfectant- Because of its oxidizing property, it can act as a disinfectant to treat skin infections such as dermatitis, canker sores, ulcers, eczema and fungal infections.
When applied to small wounds, it attacks the outer cell membrane of the microorganism thereby oxidizing it and destroying its structure. In some cases of large wounds, doctors advise potassium permanganate water baths with dilute solutions. Care must be taken as overuse of this chemical may cause irritation and burns. It can be used to clean wounds. Wet wounds like ulcers and abscesses can be cleaned with potassium permanganate solution.
This treatment kills the microbes and prevents secondary infection. It also helps in drying out the blisters. The oxidizing action of permanganate solution kills the fungus thereby relieving the symptoms such as itching and burning sensation. It can also be used to treat allergies due to reaction of commercial hair dyes.
Dyes contain an oxidizer which breaks down the melanin pigment in hair and allows for dye to penetrate. Due to incomplete action of dye and oxidizer sometimes there is an allergic reaction which causes discomfort and itchiness.
Permanganate solution is applied in such a case as a compress to relieve the symptoms and to completely oxidize the dye. Water treatment. When titrating a chemical you can determine its concentration by adding it to a known amount of another chemical until a color change happens.
Once the exact concentration has been determined, the solution is said to be standardized and you can then add exact amounts of the KMnO4 to a chemical reaction.
This compound is a strong oxidizing agent because elements become more electronegative as the oxidation states of their atoms increase. The permanganate in potassium permanganate has the anion MnO4- that is the reason for its strong oxidizing properties. The oxalic acid acts as a reducing agent, and the KMnO 4 acts as an oxidizing agent. KMnO4 acts as an indicator of where the permanganate ions are a deep purple colour. KMnO4 is a very strong oxidizing agent and it can oxidize HCl to liberate chlorine gas, therefore HCl cannot be used to acidify potassium permanganate solution in volumetric analysis.
Why KMnO4 is Coloured? Potassium permanganate KMnO4 is colored because it absorbs light in the visible range of the electromagnetic spectrum. The permanganate ion is the source of the color, as a ligand-to-metal charge transfer takes place between the oxygen's p orbitals and the empty d-orbitals on the metal. Why h2so4 is added in KMnO4 titration? Why KMnO4 is a self indicator? So once all the permanganate ions are used up in the reaction, the solution loses its pink colour.
This indicates the end of the reaction and hence potassium permanganate is called a self indicator as it acts as an indicator apart from being one of the reactants. What is KMnO4 used for? Medical uses Potassium permanganate is used for a number of skin conditions. This includes fungal infections of the foot, impetigo, pemphigus, superficial wounds, dermatitis, and tropical ulcers. Why h2so4 is added in redox titration? Therefore, sulfuric acid is added to make the solution acidic.
Why is k2cr2o7 not a self indicator? Potassium dichromate acts as oxidizing agent in acidic medium only. Thus an indicator is must in this titration. What is end point in titration? End Point. Why is standardization of NaOH important?
First of all, solid NaOH absorbs water from the air, so accurately weighing a sample during the preparation of a solution is impossible. Once the NaOH solution has been standardized and its concentration is well-known, it can be used to titrate other acid solutions such as HCl.
Why is standardization important in titration?
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