Potassium nitrate (KNO3) is a white crystalline salt often used in fertilizers, food preservation, and fireworks. It’s also a key ingredient in some toothpaste for sensitive teeth.
| IUPAC Name | Potassium nitrate |
| Molecular Formula | KNO3 |
| CAS Number | 7757-79-1 |
| Synonyms | saltpeter; nitrate of potash; niter; saltpetre; E252; Chinese saltpetre; nitric acid, potassium salt; Kalii nitras |
| InChI | InChI=1S/K.NO3/c;2-1(3)4/q+1;-1 |
Potassium Nitrate Properties
Potassium Nitrate Formula
The chemical formula for potassium nitrate is KNO3. This formula shows that the compound is made up of one potassium ion, one nitrate ion, and three oxygen ions. The formula is useful for calculating the amount of potassium nitrate needed in a reaction, as well as for identifying the elements and ions present in the compound.
Potassium Nitrate Molar Mass
KNO3 has a molar mass of 101.1 g/mol. The molar mass is the mass of one mole of a substance and is calculated by summing the atomic masses of all the atoms in the compound. In the case of KNO3, the molar mass is calculated by adding the atomic mass of one potassium atom, one nitrogen atom, and three oxygen atoms. This value is useful for determining the amount of KNO3 needed in a reaction and for calculating other properties such as concentration.
Potassium Nitrate Boiling Point
KNO3 has a relatively high boiling point of 1,336 °C (2,437 °F). This means that it requires a lot of energy to break the bonds between the atoms in the compound and convert it from a liquid to a gas. This property makes KNO3 useful in applications that require high-temperature reactions, such as in the manufacturing of fireworks.
Potassium Nitrate Melting Point
KNO3 has a melting point of 334 °C (633 °F). This means that at temperatures above 334 °C, KNO3 will transition from a solid to a liquid. This property makes KNO3 useful in applications such as the manufacturing of glass, where it is used as a flux to lower the melting point of the silica.
Potassium Nitrate Density g/mL
The density of KNO3 is 2.109 g/mL at room temperature. Density is a measure of the mass per unit volume of a substance. The density of KNO3 is important in applications such as fertilizer production, where it is used as a source of nitrogen and potassium. The density is also useful for determining the amount of KNO3 needed in a given volume of solution.
Potassium Nitrate Molecular Weight
The molecular weight of KNO3 is 101.1 g/mol. This value is calculated by summing the atomic weights of all the atoms in the compound. The molecular weight is useful for calculating other properties of KNO3, such as the amount of KNO3 needed in a reaction or the concentration of a solution.
Potassium Nitrate Structure
KNO3 has a crystalline structure that consists of ions of potassium, nitrate, and oxygen. The potassium ions are surrounded by six nitrate ions, while the nitrate ions are surrounded by six potassium ions. This structure gives KNO3 its characteristic properties such as solubility, melting point, and density.
| Appearance | White crystalline powder |
| Specific Gravity | 2.109 g/cm³ at 20°C |
| Color | White |
| Odor | Odorless |
| Molar Mass | 101.1032 g/mol |
| Density | 2.109 g/cm³ |
| Melting Point | 334°C (633°F) |
| Boiling Point | 400°C (752°F) |
| Flash Point | Not applicable |
| Water Solubility | 133 g/L at 20°C |
| Solubility | Soluble in glycerol, ammonia, and water |
| Vapour Pressure | Negligible |
| Vapour Density | Not applicable |
| pKa | 4.75 |
| pH | 6.9 – 7.3 |
Potassium Nitrate Safety and Hazards
KNO3 is relatively safe when handled properly, but it can pose hazards if mishandled. It is classified as an oxidizer, meaning it can enhance the combustion of other materials. KNO3 can also irritate the eyes, skin, and respiratory tract, and it can be toxic if ingested or inhaled in large amounts. It is important to wear protective equipment such as gloves, goggles, and a respirator when handling KNO3, and to store it in a cool, dry place away from flammable materials. Proper disposal methods should also be followed to avoid environmental contamination.
| Hazard Symbols | O, Xn |
| Safety Description | Keep away from heat/sparks/open flames/hot surfaces. Wear protective gloves/eye protection/face protection. IF SWALLOWED: Call a POISON CENTER/doctor if you feel unwell. Rinse mouth. DO NOT induce vomiting. IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing. Call a POISON CENTER/doctor. |
| UN IDs | 1486 |
| HS Code | 2834.21.00 |
| Hazard Class | 5.1 |
| Packing Group | III |
| Toxicity | May cause respiratory irritation, coughing, and shortness of breath if inhaled. May cause eye and skin irritation. Ingestion may cause abdominal pain, nausea, vomiting, and diarrhea. Can be toxic if ingested or inhaled in large amounts. |
Potassium Nitrate Synthesis Methods
Several methods can synthesize KNO3.
One common method is the reaction between potassium hydroxide and nitric acid. The reaction vessel mixes the two substances and heats them to a high temperature, typically around 80°C. After that, the mixture cools down, and the filtration process collects the solid KNO3.
Another method is the reaction between potassium chloride and sodium nitrate. A person mixes the two substances in a reaction vessel and heats them to a high temperature, usually around 600°C.
The resulting mixture melts and then solidifies, forming KNO3 crystals.
A third method involves the oxidation of ammonia by nitric acid in the presence of a catalyst. This method is more complex and typically used on an industrial scale.
One can extract KNO3 from natural sources, such as caves and deposits in the earth. However, this method is less common due to the low yields and impurities in the extracted KNO3.
Potassium Nitrate Uses
KNO3 has a wide range of uses in various industries due to its chemical properties. Here are some common uses of KNO3:
- Fertilizer – Used as a fertilizer due to its high nitrogen and potassium content. It is particularly useful for crops that require high potassium levels, such as fruits, vegetables, and tobacco.
- Food preservation – Also used as a food preservative, particularly in cured meats. It inhibits the growth of bacteria and prevents spoilage, extending the shelf life of the product.
- Pyrotechnics – It is a key component in the manufacture of fireworks and other pyrotechnic devices. It acts as an oxidizer, producing oxygen to fuel the combustion of other materials.
- Toothpaste – Added to some toothpastes to reduce tooth sensitivity. It works by blocking the transmission of pain signals from the tooth nerve to the brain.
- Medicinal uses – Used in medicine for its diuretic and expectorant properties. It also treats angina and hypertension.
- Industrial applications – Also used in various industrial applications, such as in the production of glass, ceramics, and dyes.
Questions:
Q: Is potassium nitrate soluble in water?
A: Yes, KNO3 is highly soluble in water. At room temperature, 100 grams of water can dissolve approximately 37 grams of KNO3.
Q: What is potassium nitrate used for?
A: KNO3 is used for a variety of purposes, including as a fertilizer, food preservative, pyrotechnic oxidizer, toothpaste ingredient, and as a component in the production of glass, ceramics, and dyes.
Q: What is potassium nitrate?
A: Potassium nitrate, also known as saltpeter, is a chemical compound with the formula KNO3. It is an ionic salt consisting of potassium ions (K+) and nitrate ions (NO3-).
Q: What counteracts potassium nitrate?
A: Calcium and magnesium ions can counteract the harmful effects of excessive KNO3 intake in plants. In humans, there is no known antidote for KNO3 poisoning, and treatment is supportive.
Q: Is kno3 soluble in water?
A: Yes, KNO3 is highly soluble in water.
Q: Which is a product of the electrolysis of water containing a low concentration of kno3?
A: The products of electrolysis of water containing a low concentration of KNO3 are hydrogen gas (H2) and oxygen gas (O2).
Q: What is kno3?
A: KNO3 is the chemical formula for potassium nitrate, also known as saltpeter.
Q: What is the oxidation state of an individual nitrogen atom in kno3?
A: In KNO3, the oxidation state of the individual nitrogen atom is +5.
Q: Is kno3 an acid or base?
A: KNO3 is neither an acid nor a base. It is a salt, composed of a cation (K+) and an anion (NO3-).