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Bases are proton acceptors; a base will receive a hydrogen ion from water, H 2 O, and the remaining H + concentration in the solution determines pH. A weak base will have a higher H + concentration than a stronger base because it is less completely protonated than a stronger base and, therefore, more hydrogen ions remain in its solution.
C A is the analytical concentration of the acid and C H is the concentration the hydrogen ion that has been added to the solution. The self-dissociation of water is ignored. A quantity in square brackets, [X], represents the concentration of the chemical substance X. It is understood that the symbol H + stands for the hydrated hydronium ion.
When some strong acid is added to an equilibrium mixture of the weak acid and its conjugate base, hydrogen ions (H +) are added, and the equilibrium is shifted to the left, in accordance with Le Chatelier's principle. Because of this, the hydrogen ion concentration increases by less than the amount expected for the quantity of strong acid added.
Bases and acids are seen as chemical opposites because the effect of an acid is to increase the hydronium (H 3 O +) concentration in water, whereas bases reduce this concentration. A reaction between aqueous solutions of an acid and a base is called neutralization , producing a solution of water and a salt in which the salt separates into its ...
Water itself is a weak acid and a weak base, so its dissociation must be taken into account at high pH and low solute concentration (see Amphoterism). It dissociates according to the equilibrium 2 H 2 O ⇌ H 3 O + (aq) + OH − (aq)
The Henderson–Hasselbalch equation assumes that the autoionization of water is negligible and that the dissociation or hydrolysis of the acid and the base in solution are negligible (in other words, that the formal concentration is the same as the equilibrium concentration). For an acid-base equilibrium such as HA ⇌ H + + A −, the Charlot ...
With weak bases addition of acid is not quantitative because a solution of a weak base is a buffer solution. A solution of a weak acid is also a buffer solution. When a weak acid reacts with a weak base an equilibrium mixture is produced. For example, adenine, written as AH, can react with a hydrogen phosphate ion, HPO 2− 4.
Outside the transition range the concentration of acid or conjugate base is less than 10 % and the colour of the major species dominates. Species concentrations calculated with the program HySS for a 10 mM solution of citric acid. pK a1 = 3.13, pK a2 = 4.76, pK a3 = 6.40. A weak acid may be defined as an acid with pK a greater than