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14: Equilibrio de ácido-base

  • Page ID
    1909
    • Contributed by

    Este capítulo ilustra la química de las reacciones ácido-base y los equilibrios, y le dará las herramientas necesarias para cuantificar las concentraciones de los ácidos y los bases en las soluciones.

    • 14.1: Los ácidos y bases de Brønsted-Lowry
      Los compuestos que donan un protón (ion de hidrógeno) se llaman ácidos Brønsted-Lowry. El compuesto que acepta el protón se llama la base Brønsted-Lowry. La especie que ha perdido un protón es la base conjugada del ácido. La especie formada cuando una base Brønsted-Lowry gana un protón es el ácido conjugado de la base. Las especies anfibróticas pueden actuar como donantes de protones y aceptores de protones. El agua es la especie anfibrótica más importante.
    • 14.2: pH y pOH
      La concentración de los iones de hidronio en una solución de un ácido en el agua es mayor que 1.0×10−7 M a 25 °C. La concentración de ion de hidróxido en una solución de una base en el agua es mayor que 1.0×10−7 M a 25 °C. La concentración de H3O+ en una solución se puede expresar como el pH de la solución; pH=−logH3O+. La concentración de OH− se puede expresar como el pOH de la solución: pOH=−log[OH−]. En el agua pura, pH = 7 y pOH = 7.
    • 14.3: Relative Strengths of Acids and Bases
      The strengths of Brønsted-Lowry acids and bases in aqueous solutions can be determined by their acid or base ionization constants. Stronger acids form weaker conjugate bases, and weaker acids form stronger conjugate bases. Thus strong acids are completely ionized in aqueous solution because their conjugate bases are weaker bases than water. Weak acids are only partially ionized because their conjugate bases are compete successfully with water for possession of protons.
    • 14.4: Hydrolysis of Salt Solutions
      The characteristic properties of aqueous solutions of Brønsted-Lowry acids are due to the presence of hydronium ions; those of aqueous solutions of Brønsted-Lowry bases are due to the presence of hydroxide ions. The neutralization that occurs when aqueous solutions of acids and bases are combined results from the reaction of the hydronium and hydroxide ions to form water. Some salts formed in neutralization reactions may make the product solutions slightly acidic or slightly basic.
    • 14.5: Polyprotic Acids
      An acid that contains more than one ionizable proton is a polyprotic acid. The protons of these acids ionize in steps. The differences in the acid ionization constants for the successive ionizations of the protons in a polyprotic acid usually vary by roughly five orders of magnitude. As long as the difference between the successive values of Ka of the acid is greater than about a factor of 20, it is appropriate to break down the calculations of the concentrations sequentially.
    • 14.6: Buffers
      A solution containing a mixture of an acid and its conjugate base, or of a base and its conjugate acid, is called a buffer solution. Unlike in the case of an acid, base, or salt solution, the hydronium ion concentration of a buffer solution does not change greatly when a small amount of acid or base is added to the buffer solution. The base (or acid) in the buffer reacts with the added acid (or base).
    • 14.7: Acid-Base Titrations
      A titration curve is a graph that relates the change in pH of an acidic or basic solution to the volume of added titrant. The characteristics of the titration curve are dependent on the specific solutions being titrated. The pH of the solution at the equivalence point may be greater than, equal to, or less than 7.00. The choice of an indicator for a given titration depends on the expected pH at the equivalence point of the titration, and the range of the color change of the indicator.
    • 14.8: Acid-Base Equilibria (Exercises)
      These are homework exercises to accompany the Textmap created for "Chemistry" by OpenStax.

    Contribuyentes

    • Paul Flowers (Universidad de Carolina del Norte - Pembroke), Klaus Theopold (Universidad de Delaware) y Richard Langley (Stephen F. Austin Universidad del Estado) con autores contribuyentes. Contenido del libro de texto producido por la Universidad de OpenStax tiene licencia de Atribución de Creative Commons Licencia 4.0 licencia. Descarge gratis en http://cnx.org/contents/85abf193-2bd...a7ac8df6@9.110)."

    • Ana Martinez (amartinez02@saintmarys.edu) contribuyó a la traducción de este texto.