Acid Dissociation of Phosphoric Acid
Acid Dissociation of Phosphoric Acid
Phosphoric acid is a triprotic acid, meaning it can donate three protons in solution. When phosphoric acid is dissolved in water, it undergoes dissociation to form hydronium ion and dihydrogen phosphate.
Equation for Dissociation of Phosphoric Acid
The chemical equation for the dissociation of phosphoric acid in water can be written as follows:
H₃PO₄ + H₂O ⇌ H₃O⁺ + H₂PO₄⁻
Acid Dissociation Expression (Ka)
The acid dissociation constant (Ka) for phosphoric acid is a measure of its ability to donate protons in solution. The expression for Ka for phosphoric acid is given by:
Ka = [H₃O⁺][H₂PO₄⁻] / [H₃PO₄]
Where [H₃O⁺] represents the concentration of hydronium ions, [H₂PO₄⁻] represents the concentration of dihydrogen phosphate ions, and [H₃PO₄] represents the concentration of phosphoric acid.
Overall, the dissociation of phosphoric acid results in the formation of hydronium ion and dihydrogen phosphate, with a Ka value of 7.5 x 10⁻³.