How to calculate buffer solution concentration from ph?
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pKa: A quantitative measure of the strength of an acid in solution; a weak acid has a pKa value in the approximate range −2 to 12 in water and a strong acid has a pKa value of less than about −2.
Buffers
A buffer is an aqueous solution containing a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer’s pH changes very little when a small amount of strong acid or base is added to it. It is used to prevent any change in the pH of a solution, regardless of solute. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. For example, blood in the human body is a buffer solution.
Buffer solutions are resistant to pH change because of the presence of an equilibrium between the acid (HA) and its conjugate base (A–). The balanced equation for this reaction is:
HA
⇌
H
+
+
A
−
HA⇌H++A−
When some strong acid (more H+) is added to an equilibrium mixture of the weak acid and its conjugate base, the equilibrium is shifted to the left, in accordance with Le Chatelier’s principle. This causes the hydrogen ion (H+) concentration to increase by less than the amount expected for the quantity of strong acid added. Similarly, if a strong base is added to the mixture, the hydrogen ion concentration decreases by less than the amount expected for the quantity of base added. This is because the reaction shifts to the right to accommodate for the loss of H+ in the reaction with the base.
Buffers
A buffer is an aqueous solution containing a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer’s pH changes very little when a small amount of strong acid or base is added to it. It is used to prevent any change in the pH of a solution, regardless of solute. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. For example, blood in the human body is a buffer solution.
Buffer solutions are resistant to pH change because of the presence of an equilibrium between the acid (HA) and its conjugate base (A–). The balanced equation for this reaction is:
HA
⇌
H
+
+
A
−
HA⇌H++A−
When some strong acid (more H+) is added to an equilibrium mixture of the weak acid and its conjugate base, the equilibrium is shifted to the left, in accordance with Le Chatelier’s principle. This causes the hydrogen ion (H+) concentration to increase by less than the amount expected for the quantity of strong acid added. Similarly, if a strong base is added to the mixture, the hydrogen ion concentration decreases by less than the amount expected for the quantity of base added. This is because the reaction shifts to the right to accommodate for the loss of H+ in the reaction with the base.
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