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Aug 14, 2020 · Key Equations. Acid ionization constant: \[K_a=\dfrac{[H_3O^+][A^−]}{[HA]} onumber \] Base ionization constant: \[K_b= \dfrac{[BH^+][OH^−]}{[B]} onumber \] Relationship between \(K_a\) and \(K_b\) of a conjugate acid–base pair: \[K_aK_b = K_w onumber \]
It is the equilibrium constant for a chemical reaction. known as dissociation in the context of acid–base reactions. The chemical species HA is an acid that dissociates into A−, called the conjugate base of the acid, and a hydrogen ion, H+.
About. Transcript. One way to determine the pH of a buffer is by using the Henderson–Hasselbalch equation, which is pH = pKₐ + log ( [A⁻]/ [HA]). In this equation, [HA] and [A⁻] refer to the equilibrium concentrations of the conjugate acid–base pair used to create the buffer solution.
- 8 min
- Jay
- What Is The Henderson-Hasselbalch equation?
- Table of Contents
- Equation of Henderson-Hasselbalch
- Derivation of The Henderson-Hasselbalch Equation
- Important Points to Remember
- Limitations of The Henderson-Hasselbalch Equation
- Solved Example
The Henderson-Hasselbalch equation provides a relationship between the pH of acids (in aqueous solutions) and their pKa(acid dissociation constant). The pH of a buffer solution can be estimated with the help of this equation when the concentration of the acid and its conjugate base, or the base and the corresponding conjugate acid, are known.
The Henderson-Hasselbalch equation can be written as: pH = pKa + log10 ([A–]/[HA]) Where [A–] denotes the molar concentration of the conjugate base (of the acid) and [HA] denotes the molar concentration of the weak acid. Therefore, the Henderson-Hasselbalch equation can also be written as: An equation that could calculate the pH value of a given bu...
The ionization constants of strong acids and strong bases can be easily calculated with the help of direct methods. However, the same methods cannot be used with weak acids and bases since the extent of ionization of these acids and basesis very low (weak acids and bases hardly ionize). Therefore, in order to approximate the pH of these types of so...
When exactly half of the acid undergoes dissociation, the value of [A]/[HA] becomes 1, implying that the pKa of the acid is equal to the pH of the solution at this point. (pH = pKa + log10(1) = pKa).For every unit change in the pH to pKa ratio, a tenfold change occurs in the ratio of the associated acid to the dissociated acid. For example, when the pKa of the acid is 7 and the pH of the solut...The value of [A–]/[HA] is dependent on the value of the pH and pKa. When pH < pKa; [A–]/[HA] < 1. When pH > pKa; [A–]/[HA] > 1.The Henderson-Hasselbalch equation fails to predict accurate values for the strong acids and strong bases because it assumes that the concentration of the acid and its conjugate base at chemical equilibriumwill remain the same as the formal concentration (the binding of protons to the base is neglected). Since the Henderson-Hasselbalch equation doe...
A buffer solution is made from 0.4M CH3COOH and 0.6M CH3COO–. If the acid dissociation constant of CH3COOH is 1.8*10-5, what is the pH of the buffer solution? As per the Henderson-Hasselbalch equation, pH = pKa + log([CH3COO–]/[CH3COOH]) Here, Ka = 1.8*10-5 ⇒ pKa= -log(1.8*10-5) = 4.7 (approx.). Substituting the values, we get: pH = 4.7 + log(0.6M ...
Mar 25, 2023 · Ka = [H+] [A-]/ [HA] Taking the negative logarithm of both sides gives the following equation: -log (Ka) = -log ( [H+] [A-]/ [HA]) By definition: pKa = -log (Ka) and pH = -log ( [H+]) Substitute these expressions into the equation: pKa = pH + log ( [HA]/ [A-]) Rearranging the equation gives the Henderson-Hasselbalch equation for weak acids:
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Feb 28, 2022 · Page ID. Gamini Gunawardena. Utah Valley University. The following equation, which relates the pH of an aqueous solution of an acid to the acid dissociation constant of the acid, is known as the Henderson-Hasselbach equation. pH = pkA +log10 [conjugate base] [weak acid] (1) (1) p H = p k A + log 10.
Jan 30, 2023 · Surface tension is the energy, or work, required to increase the surface area of a liquid due to intermolecular forces. Since these intermolecular forces vary depending on the nature of the liquid (e.…
