Polyprotic Acid
What is Polyprotic Acid?
A polyprotic acid is an acid that can donate more than one proton (H⁺) per molecule in successive ionisation steps. Diprotic acids (H₂SO₄, H₂CO₃) can donate two protons; triprotic acids (H₃PO₄) can donate three. Each successive ionisation is characterised by a progressively smaller dissociation constant (Ka₁ > Ka₂ > Ka₃), as it becomes harder to remove a proton from an increasingly negative ion.
Key Facts
Frequently Asked Questions
A polyprotic acid is an acid that can donate more than one proton (H⁺) per molecule in successive ionisation steps. Diprotic acids (H₂SO₄, H₂CO₃) can donate two protons; triprotic acids (H₃PO₄) can donate three. Each successive ionisation is characterised by a progressively smaller dissociation constant (Ka₁ > Ka₂ > Ka₃), as it becomes harder to remove a proton from an increasingly negative ion.