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:
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First Dissociation:
H₃PO₄ → H⁺ + H₂PO₄⁻
Vocabulary: H₂PO₄⁻ is called the dihydrogen phosphate ion.
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Second Dissociation:
H₂PO₄⁻ → H⁺ + HPO₄²⁻
Vocabulary: HPO₄²⁻ is known as the hydrogen phosphate ion.
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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.
