The chemical formula for potassium hydrogen phosphate is K₂HPO₄.
Potassium hydrogen phosphate, also widely known as dipotassium phosphate, is an inorganic compound with diverse applications in food, agriculture, and chemical industries. This salt is formed from potassium ions and the hydrogen phosphate anion.
Understanding Potassium Hydrogen Phosphate (K₂HPO₄)
Potassium hydrogen phosphate is a crucial compound in many biological and industrial processes. Its formula indicates the presence of two potassium atoms (K), one hydrogen atom (H), and one phosphate group (PO₄).
Chemical Composition
To understand the formula K₂HPO₄, let's break down its constituent ions:
- Potassium Ion (K⁺): Potassium is an alkali metal that typically forms a univalent cation (loses one electron).
- Hydrogen Phosphate Ion (HPO₄²⁻): This is an anion derived from phosphoric acid (H₃PO₄). When two of the three acidic hydrogen atoms are removed, the remaining ion is HPO₄²⁻, carrying a -2 charge.
For the compound to be electrically neutral, two potassium ions (each with a +1 charge) are needed to balance the -2 charge of one hydrogen phosphate ion.
K⁺ + K⁺ + HPO₄²⁻ → K₂HPO₄
Alternative Names and Synonyms
This compound is commonly known by several names, reflecting its composition:
- Dipotassium Phosphate (DKP): This name highlights the presence of two potassium atoms. It is often used interchangeably with potassium hydrogen phosphate.
- Dipotassium Hydrogen Phosphate: A more descriptive name that explicitly mentions both potassium and hydrogen.
- Potassium Phosphate Dibasic: Another name that refers to the two hydrogen atoms that can be removed from phosphoric acid to form the hydrogen phosphate ion.
For example, the compound with the formula K₂HPO₄ is recognized as Dipotassium phosphate, as detailed by sources like PubChem.
Key Information for Potassium Hydrogen Phosphate
| Property | Value |
|---|---|
| Chemical Formula | K₂HPO₄ |
| Common Name(s) | Dipotassium Phosphate, DKP |
| Ionic Components | Potassium (K⁺), Hydrogen Phosphate (HPO₄²⁻) |
| Charge Balance | 2(K⁺) + 1(HPO₄²⁻) |
| Molar Mass | ~174.18 g/mol |
| Appearance | White, hygroscopic powder |
Common Applications of K₂HPO₄
Potassium hydrogen phosphate finds extensive use across various sectors due to its properties as a buffering agent, nutrient source, and sequestrant.
- Food Additive:
- Used as a food thickener, stabilizer, and emulsifier in dairy products, non-dairy creamers, and powdered beverages.
- Acts as a buffering agent to regulate pH in processed foods.
- Serves as a nutrient source for yeast in baking and brewing.
- Fertilizers:
- A significant source of both potassium and phosphorus, essential macronutrients for plant growth.
- Often included in hydroponic solutions and foliar sprays.
- Laboratory and Pharmaceutical:
- Used in biological buffers (e.g., in cell culture media, electrophoresis buffers) due to its pKa values near physiological pH.
- Component in some laxatives and dietary supplements.
- Chemical Industry:
- Employing its properties as a corrosion inhibitor and sequestrant.
Related Compounds
It's important to distinguish potassium hydrogen phosphate from other potassium phosphates:
- Monopotassium Phosphate (KH₂PO₄): Also known as potassium dihydrogen phosphate or potassium phosphate monobasic. Here, only one hydrogen atom has been removed from phosphoric acid, resulting in the dihydrogen phosphate ion (H₂PO₄⁻). The formula is KH₂PO₄.
- Tripotassium Phosphate (K₃PO₄): Also known as potassium phosphate tribasic. In this compound, all three hydrogen atoms have been removed from phosphoric acid, leaving the phosphate ion (PO₄³⁻). The formula is K₃PO₄.
These variations highlight how the number of hydrogen atoms associated with the phosphate group and the corresponding charge influence the number of potassium ions required to form a neutral compound.
Safety and Handling
Like many chemical compounds, potassium hydrogen phosphate should be handled with care. While generally recognized as safe (GRAS) for food use in appropriate quantities, concentrated forms can be irritating. Always refer to Material Safety Data Sheets (MSDS) for specific handling and safety guidelines.
