Acid Dissociation Constant
Acid Dissociation Constant - Related Videos
03:02
Acid/Base Strengths and Dissociation Constants
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2025
The relative strength of an acid or base is the extent to which it ionizes when dissolved in water. If the ionization reaction is essentially complete, the acid or base is termed strong; if relatively little ionization occurs, the acid or base is weak. There are many more weak acids and bases than strong ones. The most common strong acids and bases are listed below: Strong Acids Strong Bases HClO4 LiOH HCl NaOH HBr KOH HI Ca(OH)2
12:38
Titration ELISA as a Method to Determine the Dissociation Constant of Receptor Ligand Interaction
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Cited by 29 •
2018
A detailed protocol to perform a titration ELISA is described. Moreover, a novel algorithm is presented to evaluate titration ELISAs and to obtain a dissociation constant of binding of a soluble ligand to a microtiter plate-immobilized receptor.
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The Equilibrium Binding Constant and Binding Strength
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2020
The equilibrium binding constant (Kb) quantifies the strength of a protein-ligand interaction. Kb can be calculated as follows when the reaction is at equilibrium: where P and L are the unbound protein and ligand, respectively, and PL is the protein-ligand complex. As the amount of bound ligand is also related to the rate of ligand binding, experiments can also determine Kb by examining the rates of protein-ligand association (kon) and dissociation (koff) using the following ratio: Thus,...
03:02
Constant Pressure Calorimetry
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2020
Calorimetry is a technique used to measure the amount of heat involved in a chemical or physical process or to measure the heat transferred to or from a substance. The heat is exchanged with a calibrated and insulated device called the calorimeter. Calorimetry experiments are based on the assumption that there is no heat exchange between the insulated calorimeter and the external environment. The well-insulated calorimeters prevent the transfer of heat between the calorimeter and its external...
09:03
Spectrophotometric Determination of an Equilibrium Constant
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2023
Source: Laboratory of Dr. Michael Evans — Georgia Institute of Technology The equilibrium constant, K, for a chemical system is the ratio of product concentrations to reactant concentrations at equilibrium, each raised to the power of their respective stoichiometric coefficients. Measurement of K involves determination of these concentrations for systems in chemical equilibrium. Reaction systems containing a single colored component can be studied spectrophotometrically. The relation between...
FAQs
The pKa scale converts Ka values into a more convenient logarithmic form, making differences in acid strength easier to compare across compounds. A larger Ka corresponds to a smaller pKa and indicates greater proton donation at equilibrium. This ranking helps chemists select acids, conjugate bases, and reaction conditions when relative proton-transfer tendencies matter.
For a weak acid, Ka relates the equilibrium concentrations of hydronium, the conjugate base, and the undissociated acid. The ratio indicates how the acid population is distributed after proton transfer reaches equilibrium. Comparing these concentrations shows whether the solution contains mostly HA or relatively more dissociated species, which affects acidity and chemical behavior.
The conjugate base is the species remaining after an acid donates a proton, so its equilibrium concentration helps reveal the extent of dissociation. A stronger acid produces a greater proportion of conjugate base relative to undissociated acid under comparable conditions. This relationship is central to analyzing proton transfer and identifying predominant chemical forms.
Ka characterizes an acid’s dissociation equilibrium, whereas pH describes the acidity of a particular solution through its hydronium concentration. A Ka value can therefore help predict pH, but the two quantities are not interchangeable. Distinguishing them allows chemists to separate an acid’s dissociation tendency from the solution conditions that determine its observed acidity.
Ka values provide the equilibrium relationship needed to assess hydronium concentration after an acid is placed in solution. Combining the constant with the relevant concentration information indicates how much acid dissociates and therefore supports pH prediction. This approach is especially useful when comparing weak acids or evaluating how solution composition changes acidity.
Buffer design uses acid dissociation behavior to select an acid and its conjugate base that can participate in proton transfer while maintaining a desired solution condition. Ka and pKa help compare candidate acid systems and anticipate their behavior as conditions change. These values therefore guide practical choices in analytical chemistry and related laboratory work.
In titration analysis, Ka and pKa help interpret acid-base behavior and support determination of solution characteristics. In pharmaceutical research, they help explain how molecular ionization changes with conditions, which can influence solubility and reactivity. The same information supports reaction planning and understanding why a compound may appear in different predominant forms.