6.12: Constante de ionización ácido-base
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Constante de ionización ácido-base
John Moore, Jia Zhou y Etienne Garand
Constantes de ionización para ácidos selectos (a continuación se muestra una tabla para bases)
K a determinado a 25 °C.
| Ácido | Fórmula y Ecuación de Ionización | K a | p K a |
|---|---|---|---|
| Acético | CH3COOH + H₂O H3O+ + CH3COO - | 1.8 × 10-⁵ | 4.74 |
| Arsénico | H3AsO⁴ + H₂O H3O+ + H₂AsO⁴ − | K¹ = 6.17 × 10-³ | 2.210 |
| H₂AsO⁴ − + H₂O H3O₂ + HASO₂²− | K₂ = 1,17 × 10-6.7 | 6.932 | |
| HASO⁴ ²− + H₂O H3O+ + ASo₂³ − | K₃ = 3.09 × 10-¹² | 11.523 | |
| benzoico | C6H5COOH + H₂O H3O+ + C6H5COO - | 1.2 × 10-⁴ | 3.92 |
| Boric | B (OH) ₃ (H₂O) + H₂O H3O+ B (OH) ⁴ − | 5.8 × 10-¹⁰ | 9.24 |
| Butírico | CH3CH₂CH₂COOH + H₂O H3O3+ + CH3CH₂CH₂COO - | 1.5 × 10-⁵ | 4.82 |
| Carbónico | H₂CO₃ + H₂O H3O3+ + HCO₃ − | K¹= 4.3 × 10-7.3 | 6.37 |
| HCO₃ − + H₂O H3O3+ + CO3²− | K₂ = 4.7 × 10-¹¹ | 10.33 | |
| Cítrico | H₃ C6H5O7 + H₂O H3O+ + H₂C6H5O7 - | K¹= 1.4 × 10-³ | 2.85 |
| H₂C6H5O7 − + H₂O H3O₂ + HC6H5O7²− | K₂ = 4.5 × 10-⁵ | 4.35 | |
| HC6H5O7²− + H₂O H3O₂ + C6H5O7³ − | K₃ = 1.5 × 10-s6 | 5.82 | |
| Cloroacético | CH₂ClCOOH + H₂O H3O3+ + CH₂ClCoO - | 1.4 × 10 -3 | 2.85 |
| 4-clorobutírico | CH₂ClCH₂CH₂COOH + H₂O H3O3+ + CH₂ClCH₂CH₂COO - | 3.0 × 10 -5 | 4.53 |
| Ácido 3-clorobutírico | CH3CHClCH₂COOH + H₂O H3O3+ + CH3CHClCH₂CoO - | 8.9 × 10 -5 | 4.05 |
| Ácido 2-clorobutírico | CH3CH₂CHClCOOH + H₂O H3O3+ + CH3CH₂CHClCoO - | 1.3 × 10 -3 | 2.89 |
| Cloroso | HClO₂ + H₂O H3O3+ + ClO₂ − | 1.1 × 10-² | 1.96 |
| Dicloroacético | CHCl 2 COOH + H₂O H3O+ + CHCl 2 COO - | 4.5 × 10 -2 | 1.35 |
| fórmico | HCOOH + H₂O H3O+ + HCOO - | 1.8 × 10-⁴ | 3.75 |
| Hidrazoico | HN₃ + H₂O H3O3+ + N₃ − | 1.0 × 10-⁵ | 5.00 |
| Clorhídrico | HCl + H₂O H3O+ + Cl - | 1.2 × 10 6 | -6.1 |
| Hidrociánico | HCN + H₂O H3O+ + CN − | 3.3 × 10-¹⁰ | 9.48 |
| Hidrofluórico | HF + H₂O H3O+ + F − | 6.8 × 10-⁴ | 3.17 |
| Peróxido de hidrógeno | H₂O₂ + H₂O H3O3+ + HO₂ − | 2.1 × 10−¹² | 11.68 |
| Hidrosulfúrico† | H₂S + H₂O H3O3+ + HS − | K¹= 1 × 10-7 | 7.0 |
| HS - + H₂O H3O3+ + S²− | K₂ = 1 × 10-¹19 | 19.0 | |
| Hipobromo | HOBr + H₂O H3O+ + OBr - | 3 × 10 -9 | 8.5 |
| Hipocloroso | HOCl + H₂O H3O+ + OCl − | 6.8 × 10-8 | 7.17 |
| Hipoyodoso | HOI + H₂O H3O+ + OI - | 3 × 10 -11 | 10.5 |
| Nítrico | HNO₃ + H₂O H3O+ + NO₃ - | 27 | -1.43 |
| Nitroso | HNO₂ + H₂O H3O3+ + NO₂ − | 7.41 × 10-⁴ | 3.130 |
| Oxálico | H₂C₂O⁴ + H₂O H3O3+ + HC₂O⁴ − | K¹= 5.5 × 10-² | 1.26 |
| HC₂O⁴ − + H₂O H3O3+ + C₂O₂²− | K₂ = 1.4 × 10-⁴ | 3.85 | |
| Fenol | HC6H5O + H₂O H3O3+ + C6H5O - | 1.7 × 10-¹⁰ | 9.77 |
| Fosfórico | H3PO4 + H₂O H3O3+ + H₂PO4 − | K¹ = 7.2 × 10-³ | 2.14 |
| H₂PO4 − + H₂O H3O₂ + HPO4²− | K₂ = 6,3 × 10-8 | 7.20 | |
| HPO4²− + H₂O H3O3+ + PO4³− | K₃ = 4.6 × 10-¹³ | 12.34 | |
| Fósforo | H3PO₃ + H₂O H3O3+ + H₂PO₃ − | K¹ = 2.4 × 10-² | 1.62 |
| H₂PO₃ − + H₂O H3O₂ + HPO3²− | K₂ = 2.9 × 10-6.7 | 6.54 | |
| Propanoico | CH3CH₂COOH + H₂O H3O+ + CH3CH₂COO - | 1.33 × 10-⁵ | 4.85 |
| Selenic | H₂SeO⁴ + H₂O H3O+ + HSeO⁴ − | K¹= muy grande | — |
| HSeO⁴ − + H₂O H3O₂ + SeO₂²− | K₂ = 2.2 × 10-² | 1.66 | |
| Selenoso | H₂SeO₃ + H₂O H3O+ + HSeO₃ − | K¹ = 2.5 × 10-³ | 2.60 |
| HSeO₃ − + H₂O H3O+ + SeO³²− | K₂ = 1,6 × 10-9 | 8.80 | |
| Sulfúrico | H₂SO⁴ + H₂O H3O3+ + HSO⁴ − | K¹= 4,0 × 10 3 | -3.6 |
| HSO⁴ − + H₂O H3O3+ + SO4²− | K₂ = 1.1 × 10-² | 1.96 | |
| sulfuroso | H₂SO₃ + H₂O H3O3+ + HSO₃ − | K¹ = 1.7 × 10-² | 1.77 |
| HSO₃ − + H₂O H3O3+ + SO3²− | K₂ = 6,3 × 10-8 | 7.2 | |
| Teluroso | H₂TeO₃ + H₂O H3O+ HTeO₃ − | K¹ = 7,1 × 10-7 | 6.15 |
| HTeO₃ − + H₂O H3O+ + TeO³²− | K₂ = 4,0 × 10-9 | 8.40 | |
| Tricloroacético | CCl 3 COOH + H₂O H3O+ + CCl 3 COO - | 0.17 | 0.77 |
| Trifluoacético | CF 3 COOH + H₂O H3O+ + CF 3 COO - | 0.30 | 0.52 |
Tomado de Hogfeldt, E. y Perrin, D. D., Constantes de Estabilidad de complejos Metal-Ion, 1a ed. Oxford: Nueva York: Pérgamo, 1979-1982. Unión Internacional de Química Pura y Aplicada Comisión de Datos de Equilibrio.
También de Serjeant, E. P. y Dempsey, B. (eds.), “Constantes de ionización de ácidos orgánicos en solución acuosa”, IUPAC Chemical Data Series No. 23, Pergamon Press, Oxford, 1979.
† De Myers, R., Revista de Educación Química, Vol. 63, 1986, pp. 687-690.
Constantes de ionización para bases selectas
K b determinado a 25 °C.
| Base | Fórmula y Ecuación de Ionización | K b | p K b |
|---|---|---|---|
| Acetilida | C₂H - + H₂O OH - + C₂H₂ | 1 × 10 11 | -11 |
| Amida | NH₂ - + H₂O OH - + NH₃ | 1 × 10 20 | -20 |
| Amoníaco ‡ | NH₃ + H₂O NH4+ + OH - | 1.77 × 10-⁵ | 4.752 |
| Anilina § | C6H5NH₂ + H₂O C6H5NH3+ OH - | 3.9 × 10-¹⁰ | 9.41 |
| Dimetilamina § | (CH₃) ₂NH + H₂O (CH₃) ₂NH₂+ OH - | 5.8 × 10-⁴ | 3.24 |
| etóxido | CH3CH₂O - + H₂O OH - + CH₃ CH₂OH | 1 × 10 2 | -2 |
| Etilendiamina | (CH₂) ₂ (NH₂) ₂ + H₂O (CH₂) ₂ (NH₂) ₂H+ OH - | K¹ = 7,8 × 10-⁵ | 4.11 |
| (CH₂) ₂ (NH₂) ₂H + H₂O (CH₂) ₂ (NH₂) ₂H₂ ²+ OH - | K₂ = 2.1 × 10-8 | 7.68 | |
| Hidrazina | N₂H⁴ + H₂O N₂H5 + + OH - | K¹ = 1.2 × 10-6.2 | 5.92 |
| N₂H5 + + H₂O N₂H6²+ OH - | K₂ = 1.3 × 10 -15 | 14.89 | |
| Hidruro | H - + H₂O OH - + H₂ | 1 × 10 21 | -21 |
| Hidroxilamina | NH₂OH + H₂O NH3OH + + OH - | 9.3 × 10-5.9 | 8.03 |
| Metilamina | CH3NH₂ + H₂O CH3NH₃ + OH - | 5.0 × 10-⁴ | 3.30 |
| Piridina | C5H5N + H₂O C5H5NH + OH - | 1.6 × 10-9 | 8.80 |
| Trimetilamina § | (CH₃) ₃ N + H₂O (CH₃) 3NH + OH - | 6.2 × 10-⁵ | 4.21 |
Tomado de Hogfeldt, E. y Perrin, D. D., Constantes de Estabilidad de complejos Metal-Ion, 1a ed. Oxford: Nueva York: Pérgamo, 1979-1982. Unión Internacional de Química Pura y Aplicada Comisión de Datos de Equilibrio.
También de Serjeant, E. P. y Dempsey, B. (eds.), “Constantes de ionización de ácidos orgánicos en solución acuosa”, IUPAC Chemical Data Series No. 23, Pergamon Press, Oxford, 1979.
‡ De Read, A. J., Journal of Solution Chemistry, Vol. 11, No. 9, 1982, pp. 649-664.
§ De Meites, L., Ed. Manual de Química Analítica, 1a ed. Nueva York: McGraw-Hill, 1963.