炭酸
35 {\displaystyle {\mbox{p}}K_{a1}^{*}=6.35\,}
HCO 3 − ( aq ) ↽ − − ⇀ H + ( aq ) + CO 3 2 − ( aq ) {\displaystyle {\ce {HCO_3^{-}(aq) <=> H^+(aq) + CO_3^{2-}(aq)}}} , p K a 2 = 10.33 {\displaystyle {\mbox{p}}K_{a2}=10.33\,}
K a 1 ∗ = [ H + ] [ HCO 3 − ] [ H 2 CO 3 ] + [ CO 2 ] = 4.45 × 10 − 7 {\displaystyle K_{a1}^{*}={\frac {[{\mbox{H}}^{+}][{\mbox{HCO}}_{3}^{-}]}{[{\mbox{H}}_{2}{\mbox{CO}}_{3}]+[{\mbox{CO}}_{2}]}}=4.45\times 10^{-7}}
K a 2 = [ H + ] [ CO 3 2 − ] [ HCO 3 − ] = 4.7 × 10 − 11 {\displaystyle K_{a2}={\frac {[{\mbox{H}}^{+}][{\mbox{CO}}_{3}^{2-}]}{[{\mbox{HCO}}_{3}^{-}]}}=4.7\times 10^{-11}}