What is the Difference Between Sodium Phosphate Monobasic and Dibasic?

The main difference between sodium phosphate monobasic and dibasic lies in their chemical structures and basicity in water.

• Sodium Phosphate Monobasic (NaH2PO4): This compound has the chemical formula NaH2PO4 and is also known as monosodium phosphate. It is extremely hygroscopic and soluble in water.
• Sodium Phosphate Dibasic (Na2HPO4): This compound has the chemical formula Na2HPO4 and is used to make buffer solutions in biochemistry and chromatography.

When sodium phosphate dibasic dissolves in water, the basicity in the medium is higher than when sodium phosphate monobasic dissolves in water. Both compounds are important in biological systems as buffers and are medically used as saline laxatives to treat constipation.

Comparative Table: Sodium Phosphate Monobasic vs Dibasic

The main difference between sodium phosphate monobasic and dibasic is the number of sodium ions and water molecules in their respective structures. Here is a comparison table highlighting the differences:

Sodium phosphate monobasic, also known as monosodium phosphate, has a molecular formula of NaH2PO4 and a molar mass of 120 g/mol. It contains one sodium ion, one phosphate anion (H2PO4⁻), and one water molecule. On the other hand, sodium phosphate dibasic, also known as disodium phosphate, has a molecular formula of Na2HPO4 and a molar mass of 142 g/mol. It contains two sodium ions, two phosphate anions (HPO4²⁻), and no water molecules.