The key difference between potassium nitrate and potassium sulphate is that when using them as fertilizers, potassium nitrate is more suitable for acidic soils, whereas potassium sulphate is more suitable for alkaline soils.
Both potassium nitrate and potassium sulphate are useful mainly as fertilizers. These compounds provide the soil with potassium ions, nitrate ions, and sulfur.
CONTENTS
1. Overview and Key Difference
2. What is Potassium Nitrate
3. What is Potassium Sulphate
4. Potassium Nitrate vs Potassium Sulphate in Tabular Form
5. Summary – Potassium Nitrate vs Potassium Sulphate
What is Potassium Nitrate?
Potassium nitrate is an inorganic compound having the chemical formula KNO3. It is a potassium salt known as Indian Saltpetre. This compound is an ionic salt of potassium ions and nitrate ions. Therefore, we can name it an alkali metal nitrate. This compound exists as a mineral named niter. This compound is important as a source of nitrogen.
There are many different uses of potassium nitrate, including fertilizer production, tree stump removal, rocket propellants, and fireworks. Moreover, it can be found as a major component of gunpowder. Further, processed meat has potassium nitrate, which reacts with hemoglobin and myoglobin and generates a red color.
The chemical formula of potassium nitrate is KNO3, and its molar mass is 101.102 g/mol. It is a white solid that is odorless. The density of this compound is 2.10 g/cm3, and the melting point is 334 degrees Celsius while the boiling point is 400 degrees Celsius, at which it tends to decompose. However, potassium nitrate has moderate solubility in water and is slightly soluble in ethanol. It is soluble in glycerol and ammonia. The crystal structure of this mineral is orthorhombic.
What is Potassium Sulphate?
Potassium sulphate is an inorganic compound having the chemical formula K2SO4. It is also known as sulphate of potash, arcanite, potash of sulfur, etc. It is a white, water-soluble solid that is commonly used in fertilizers to provide both potassium and sulfur.
The molar mass of this compound is 174.259 g/mol. It is odorless, and the density is 2.66 g/cm3. The melting point of this compound is 1069 degrees Celsius, and the boiling point is 1689 degrees Celsius. It is moderately soluble in water and slightly soluble in glycerol while insoluble in acetone, alcohol, and CS2.
Predominantly, potassium sulphate is used as a fertilizer, and it does not contain chloride ions that can be harmful to some plants. Potassium sulphate is favorable for many fruit and vegetable plant species. Moreover, the crude salt of this compound is used as an alternative for blast media that is similar to soda in soda blasting because it is harder and shows water solubility as well. In addition, we can use potassium sulphate in pyrotechnics in combination with potassium nitrate, which gives a purple flame.
What is the Difference Between Potassium Nitrate and Potassium Sulphate?
There are different types of fertilizers that are in use at present. However, potassium nitrate and potassium sulphate are the major components in most fertilizers. The key difference between potassium nitrate and potassium sulphate is that when using them as fertilizers, potassium nitrate is preferred for acidic soils, whereas potassium sulphate is preferred for alkaline soils.
The below infographic presents the differences between potassium nitrate and potassium sulphate in tabular form for side-by-side comparison.
Summary – Potassium Nitrate vs Potassium Sulphate
Potassium nitrate is an inorganic compound having the chemical formula KNO3, while potassium sulphate is an inorganic compound having the chemical formula K2SO4. The key difference between potassium nitrate and potassium sulphate is that potassium nitrate is preferred for acidic soils, whereas potassium sulphate is preferred for alkaline soils.
Reference:
1. “Potassium Nitrate.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine.
Image Courtesy:
1. “Potassium nitrate” By w:User:Walkerma (Public Domain) via Commons Wikimedia
2. “Arcanite” By Andrew Silver – (Public Domain) via Commons Wikimedia