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Learn everything about Monobasic Sodium Phosphate (NaH₂PO₄) and Dibasic Sodium Phosphate (Na₂HPO₄) in one place. Discover their chemical properties, pH levels, medical and food uses, and how they form phosphate buffer solutions.
Introduction
Sodium phosphate refers to a group of sodium salts derived from phosphoric acid (H₃PO₄). Among them, Monobasic Sodium Phosphate (NaH₂PO₄) and Dibasic Sodium Phosphate (Na₂HPO₄) are the most commonly used in medicine, food, water treatment, and laboratories. In this article, we will explore their chemical properties, key applications, differences, and importance so that you won’t need to search anywhere else.
Monobasic Sodium Phosphate (NaH₂PO₄)
Chemical Profile
Formula: NaH₂PO₄
Other Name: Sodium Dihydrogen Phosphate
Nature: Acidic salt (contains two replaceable hydrogens)
Appearance: White crystalline powder, highly soluble in water
pH (solution): 4.5 – 6.0 (acidic)
Uses
1. Medical Applications:
Works as a laxative for constipation relief
Used as a urinary acidifier
2. Food Industry:
Functions as an emulsifier
Helps in pH regulation
Acts as a thickener in processed foods
3. Other Applications:
Utilized in water treatment
Found in detergent formulations
Dibasic Sodium Phosphate (Na₂HPO₄)
Chemical Profile
Formula: Na₂HPO₄
Other Name: Disodium Hydrogen Phosphate
Nature: Alkaline salt (contains one replaceable hydrogen)
Appearance: White crystalline or powdered solid, soluble in water
pH (solution): 8.0 – 11.0 (alkaline)
Uses
1. Medical & Laboratory Applications:
Acts as a buffering agent to stabilize pH
Combined with monobasic sodium phosphate in laxative preparations
2. Food Industry:
Works as an emulsifier and stabilizer
Used as a leavening agent in bakery products
3. Other Applications:
Important in water purification
Used in cleaning products and detergents
Key Differences
Property Monobasic Sodium Phosphate (NaH₂PO₄) Dibasic Sodium Phosphate (Na₂HPO₄)
Sodium atoms 1 2
Hydrogen atoms 2 1
Nature Acidic salt Alkaline salt
pH Range 4.5 – 6.0 (acidic) 8.0 – 11.0 (alkaline)
Common Uses Laxatives, urinary acidifier, food thickener Buffering agent, emulsifier, water treatment
Phosphate Buffer Solution
One of the most important uses of these compounds is in phosphate buffer preparation.
By mixing Monobasic Sodium Phosphate (acidic) and Dibasic Sodium Phosphate (alkaline), a stable buffer solution is formed.
This buffer is widely used in biology, medicine, and chemistry to maintain a constant pH.
Example: In pharmaceutical formulations and biochemical research, phosphate buffers are essential for stability and accuracy.
Conclusion
Both Monobasic Sodium Phosphate and Dibasic Sodium Phosphate are essential in medicine, food processing, laboratories, and industrial uses.
The monobasic form (NaH₂PO₄) is acidic, with one sodium atom and two hydrogens.
The dibasic form (Na₂HPO₄) is alkaline, with two sodium atoms and one hydrogen.
Together, they play a crucial role in buffer formation, ensuring stable pH levels in numerous applications. Their versatility makes them indispensable in healthcare, science, and industry.


