Relationship Between pKa and pKb in Acid-Base Equilibrium
For a weak acid HA in equilibrium with its conjugate base A⁻, and the corresponding conjugate acid-base reaction of A⁻ with water, the acid dissociation constant (Ka) and base dissociation constant (Kb) are related through the autoionization constant of water (Kw): Ka × Kb = Kw. Since Kw = 1.0 × 10⁻¹⁴ in aqueous solution at 25°C, taking the negative logarithm of both sides yields pKa + pKb = 14. This relationship belongs to acid-base chemical equilibrium theory, connecting the equilibrium constants of a conjugate acid-base pair to the self-ionization equilibrium of the solvent (water).
Relationship Between pKa and pKb in Acid-Base Equilibrium
For a weak acid HA in equilibrium with its conjugate base A⁻, and the corresponding conjugate acid-base reaction of A⁻ with water, the acid dissociation constant (Ka) and base dissociation constant (…