Potassium permanganate (KMnO4) is a purple crystal compound used for various purposes, such as disinfecting water, treating skin conditions, and as a laboratory reagent. It can also be used as a powerful oxidizing agent.
| IUPAC Name | Potassium permanganate |
| Molecular Formula | KMnO4 |
| CAS Number | 7722-64-7 |
| Synonyms | Permanganate of potash, Condy’s crystals, Chameleon mineral, Hypermangan, Kalium hypermanganicum |
| InChI | InChI=1S/K.Mn.4O/q+1;;;;-1 |
Potassium Permanganate Properties
Potassium Permanganate Formula
The chemical formula of potassium permanganate is KMnO4. It consists of one potassium ion (K+), one manganese ion (MnO4^-), and four oxygen atoms (O). The formula indicates the type and number of atoms that make up the compound. It is used to write chemical equations and to calculate the mass and number of atoms present in a given amount of the substance.
Potassium Permanganate Molar Mass
KMnO4 has a molar mass of 158.034 g/mol. This means that one mole of KMnO4, which is equivalent to 6.022 x 10^23 molecules, has a mass of 158.034 grams. The molar mass of a compound is calculated by adding up the atomic masses of all the elements present in the compound. In the case of KMnO4, the molar mass is calculated by adding up the atomic masses of potassium, manganese, and oxygen.
Potassium Permanganate Boiling Point
KMnO4 does not have a definite boiling point as it decomposes before it reaches its boiling point. At atmospheric pressure, KMnO4 starts to decompose at around 240°C. When heated, it first releases oxygen and forms potassium manganate, which then further decomposes to potassium oxide and manganese oxide.
Potassium Permanganate Melting Point
KMnO4 has a high melting point of 240°C. This means that at temperatures below 240°C, KMnO4 will exist in a solid state. When heated, KMnO4 undergoes a series of chemical changes, including the release of oxygen and the formation of different manganese oxides.
Potassium Permanganate Density g/ml
The density of KMnO4 is 2.703 g/mL at room temperature. This means that one milliliter of KMnO4 weighs 2.703 grams. The density of a substance is the ratio of its mass to its volume. In the case of KMnO4, its high density makes it useful for separating it from other substances by filtration.
Potassium Permanganate Molecular Weight
The molecular weight of KMnO4 is 158.034 g/mol. This value represents the average mass of one molecule of KMnO4. It is calculated by adding up the atomic masses of potassium, manganese, and oxygen that make up the compound.
Potassium Permanganate Structure
KMnO4 has a crystalline structure with a monoclinic crystal system. Its crystals are purple in color and have a prismatic shape. The compound has an octahedral coordination geometry, with six oxygen atoms surrounding the central manganese atom. The potassium ions are located between the layers of the manganese and oxygen atoms.
| Appearance | Dark purple crystalline solid |
| Specific Gravity | 2.703 g/cm³ |
| Color | Dark purple |
| Odor | Odorless |
| Molar Mass | 158.034 g/mol |
| Density | 2.703 g/cm³ |
| Melting Point | 240°C |
| Boiling Point | Decomposes before boiling |
| Flash Point | Not applicable |
| Water Solubility | 6.38 g/L at 20°C |
| Solubility | Soluble in water, ethanol, acetone |
| Vapour Pressure | Not applicable |
| Vapour Density | Not applicable |
| pKa | 2.17 |
| pH | 7.2 – 8.9 (1% solution) |
Potassium Permanganate Safety And Hazards
KMnO4 can be hazardous if not handled properly. It is a strong oxidizing agent and can react violently with reducing agents, organic compounds, and other chemicals. It may cause skin and eye irritation and can be harmful if ingested or inhaled. The compound can also stain skin and clothing. Proper safety precautions should be taken when handling KMnO4, including wearing protective clothing, goggles, and gloves. It should be stored in a cool, dry, well-ventilated area away from incompatible materials. In case of exposure or ingestion, seek medical attention immediately.
| Hazard Symbols | O, Xn |
| Safety Description | S22, S26, S36/37/39, S45 |
| UN IDs | UN 1490 |
| HS Code | 28416100 |
| Hazard Class | 5.1 |
| Packing Group | II |
| Toxicity | Toxic if ingested or inhaled. Can cause skin and eye irritation. |
Potassium Permanganate Synthesis Methods
Various methods can synthesize KMnO4.
One method involves reacting manganese dioxide with potassium hydroxide and an oxidizing agent, such as chlorine or hydrogen peroxide.
Another method involves reacting potassium manganate with chlorine gas.
Yet another method involves reacting potassium hydroxide with manganese dioxide and then oxidizing the resulting mixture with an oxidizing agent.
The synthesis process usually involves heating the reactants to a specific temperature and maintaining the temperature for a certain period of time. The process involves filtering the resulting mixture and obtaining KMnO4 through crystallization.
Potassium Permanganate Uses
KMnO4 has a variety of uses across multiple industries due to its strong oxidizing properties. Here are some common uses of KMnO4:
- Water treatment: Used to treat water for both municipal and industrial purposes, as it can remove impurities and eliminate unpleasant odors.
- Medical applications: Used topically to treat skin conditions (eczema, dermatitis, and fungal infections).
- Laboratory use: Used as an oxidizing agent in various laboratory experiments and as a stain in biology to highlight cells and tissues.
- Agriculture: Used as a fungicide and bactericide to protect crops from harmful pests and diseases.
- Chemistry: Used in analytical chemistry to determine the concentration of certain chemicals and in organic chemistry as a reagent in chemical reactions.
- Firefighting: Used as a flame retardant and to extinguish certain types of fires.
- Industrial applications: Used in the production of chemicals, textiles, and batteries.
Questions:
Q: What gas is released when potassium permanganate is decomposed?
A: When KMnO4 is decomposed, oxygen gas (O2) is released.
Q: What is potassium permanganate?
A: Potassium permanganate is a strong oxidizing agent with the chemical formula KMnO4.
Q: What is the chemical formula for potassium permanganate?
A: The chemical formula for potassium permanganate is KMnO4.
Q: Where to buy potassium permanganate crystals?
A: KMnO4 crystals can be purchased from chemical suppliers, laboratory supply companies, and online retailers.
Q: What is KMnO4?
A: KMnO4 is the chemical formula for potassium permanganate.
Q: What is the oxidation number of manganese in KMnO4?
A: The oxidation number of manganese in KMnO4 is +7.
Q: What is the oxidation number of oxygen in KMnO4?
A: The oxidation number of oxygen in KMnO4 is -2.
Q: How many moles are in 25.0 grams of KMnO4?
A: To calculate the number of moles in 25.0 grams of KMnO4, we need to divide the given mass by the molar mass of KMnO4. The molar mass of KMnO4 is 158.034 g/mol. Therefore, there are approximately 0.158 moles of KMnO4 in 25.0 grams.