Multi-Component Equilibrium

Determine the speciation of a triprotic system (e.g., Phosphoric Acid, Citric Acid) at a specific pH.

System pH

pKa₁

pKa₂

pKa₃

α₀ [H₃A]

0.0%

α₁ [H₂A⁻]

0.0%

α₂ [HA²⁻]

0.0%

α₃ [A³⁻]

0.0%

Calculations (where h = [H⁺]):
Denominator (D) = h³ + h²K₁ + hK₁K₂ + K₁K₂K₃
α₀ = h³ / D
α₁ = h²K₁ / D
α₂ = hK₁K₂ / D
α₃ = K₁K₂K₃ / D