Potassium Nitrate - KNO3

What is Potassium Nitrate (KNO3)?

KNO3 is a chemical compound with chemical name Potassium Nitrate.

Potassium nitrate also called saltpeter or niter, a white solid soluble in water formed by fractional crystallization of sodium nitrate and potassium chloride solutions. It occurs naturally as niter in rocks in India, South Africa and Brazil. When heated it decomposes to give the nitrite and oxygen. Unlike sodium nitrate it is non-deliquescent. Potassium nitrate is used in gunpowder, fertilizers and in the laboratory preparation of nitric acid.

Synthesis of Potassium Nitrate (KNO3)

Potassium nitrate is a salt. It is prepared by neutralizing an acid. When potassium hydroxide neutralises nitric acid potassium nitrate is formed.

KOH + HNO3 → KNO3 + H2O

Neutralizing nitric acid always makes “nitrate” salts. Other acids make other types of salts.

Potassium nitrate contains potassium (a soft, light, and silver metal), oxygen, and nitrogen (a colourless and odourless gas). It is an alkali metal nitrate because it is an ionic salt of potassium ions K+ ions and nitrate ions NO3. It is solid white in colour or sometimes white to dirty grey in colour. Potassium nitrate is soluble in hot water. This compound releases oxygen when heated or decomposed. It is a strong oxidizing agent It is widely used in the removal of the stump, fireworks, fertilizers, etc. It is a major constituent of black powder and food preservation techniques.

Properties of Potassium Nitrate – KNO3

KNO3 Potassium Nitrate
Molecular Weight/ Molar Mass 101.1032 g/mol
Density 2.109 g/cm3
Boiling Point 400 °C
Melting Point 334 °C

Potassium Nitrate structure (KNO3 Structure)

Potassium Nitrate - KNO3

Potassium Nitrate Structure

Potassium Nitrate (KNO3 ) Uses

  • It is used as a form of fertilizer as it contains all the macronutrients needed for the plants to grow.
  • It is used as gunpowder in explosives such as bombs, grenades, etc.
  • Used in the manufacturing and production of cigarettes.
  • It is used extensively used in the preservation of hides
  • It has medicinal applications such as a diuretic in medicine
  • Used in toothpaste to make the teeth less sensitive to pain
  • Used in the food industry to preserve meat against microbial agents


1. Is potassium nitrate harmful to humans?
Ans: A number of health hazards can present potassium nitrate. It can trigger breathing issues when inhaled, including coughing and shortness of breath. Contact with the skin or eye can lead to discomforts such as redness, itching, and pain

2. What contains potassium nitrate?
Ans: Potassium nitrate is a nitric acid crystalline potassium salt. Many products in households, agriculture, and industry use potassium nitrate. For solar power plants, there are examples of toothpaste, fertilizers, fireworks, pesticides and molten salt.

3. Is potassium nitrate safe in toothpaste?
Ans: There is often confusion between nitrates and nitrites. The FDA recognizes nitrates used in potassium nitrate as secure and efficient for use in anti-sensitive dental products. Additionally, temporary pain relief is provided by delicate toothpaste.

4. What are the dangers of potassium nitrate?
Ans: Contact can trigger irritation of the eyes and skin. Potassium nitrate respiration may irritate the nose and throat causing sneezing and coughing. High concentrations may interfere with the blood’s capacity to carry oxygen that causes headache, tiredness, dizziness, and blue skin and lips

5. What is potassium nitrite used for?
Ans: In the production of heat transfer salts, potassium nitrite is used. Potassium nitrite as a food additive E249 is a sodium nitrite-like preservative and is approved for use in the EU, USA, Australia and New Zealand

Learn more about the Structure, physical and chemical properties of KNO3 from the experts at BYJU’S.

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