Potassium nitrate is a chemical compound. It has the chemical formula KNO3. It is an ionic salt of potassium ions K+ and nitrate ions NO3−, and is, therefore, an alkali metal nitrate. It contains potassium and nitrate ions. It is often called saltpeter. It occurs in nature as a mineral, niter. It’s commonly used as a fertilizer for high-value crops that benefit from nitrate nutrition and a source of potassium free of chloride.
Potassium nitrate is a colorless solid. It dissolves in water. It is one of several nitrogen-containing compounds collectively referred to as saltpeter or saltpeter. It is a common source of the nitrate ion. It is a common active ingredient in toothpaste, exerting an anti-sensitivity action. Potassium nitrate is a strong oxidizer. It decomposes to potassium nitrite and oxygen when heated. Its pH is almost neutral. It burns with a lilac flame.
It can be made by reacting ammonium nitrate with potassium hydroxide. It can also be made by reacting potassium chloride with ammonium nitrate. It might be made by reacting potassium hydroxide or potassium carbonate with nitric acid.
Saltpeter is a mineral form of potassium nitrate. It is only found in very dry areas. It is one of the few minerals that have nitrogen in them.
- Major uses of potassium nitrate are in fertilizers, tree stump removal, rocket propellants, and fireworks.
- It is used in explosives. Oxygen from the air is the most common chemical that is used for oxidation, which is how most fires and explosions happen.
- It is one of the major constituents of gunpowder (black powder). In processed meats, potassium nitrate reacts with hemoglobin and generates a pink color.
- It is also used in rocket fuel for the same reason as in explosives, except that the goal is to let the fuel burn longer, not faster.
- It is used as a fertilizer, to help plants grow faster and grow in more places where it might be hard for them to grow otherwise. It can also be used to decay tree stumps.
Potassium nitrate is a poison and will cause permanent injury when improperly handled. It also can start fires and explosions easily.