Stepwise Dissociation of Phosphoric Acid

The page details the dysocjacja jonowa kwasów process for phosphoric acid (H₃PO₄), a triprotic acid that undergoes stepwise dissociation. This process is crucial in understanding acid-base chemistry and ion formation in aqueous solutions.

Definition: Dysocjacja jonowa kwasów refers to the process by which acids break down in water to produce hydrogen ions (H⁺) and their corresponding anions.

The dissociation of phosphoric acid occurs in three distinct steps:

1. First Dissociation: H₃PO₄ → H⁺ + H₂PO₄⁻

   Vocabulary: H₂PO₄⁻ is called the dihydrogen phosphate ion.

2. Second Dissociation: H₂PO₄⁻ → H⁺ + HPO₄²⁻

   Vocabulary: HPO₄²⁻ is known as the hydrogen phosphate ion.

3. Third Dissociation: HPO₄²⁻ → H⁺ + PO₄³⁻

   Vocabulary: PO₄³⁻ is the phosphate ion.

Highlight: Each step of the dissociation produces a hydrogen ion (H⁺) and an increasingly negative phosphate species.

The page also notes that the concentration of PO₄³⁻ ions is much lower than that of HPO₄²⁻ and H₂PO₄⁻ ions. This information is crucial for understanding the relative strengths of each dissociation step and the predominant species present in phosphoric acid solutions at different pH levels.

Example: In a solution of phosphoric acid, you would find H⁺, H₂PO₄⁻, HPO₄²⁻, and PO₄³⁻ ions, but in different concentrations depending on the pH of the solution.

Understanding this stepwise dysocjacja jonowa kwasów process is essential for predicting acid-base behavior, calculating pH, and determining buffer capacities in biochemical and environmental systems where phosphates play a crucial role.