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A buffer is an aqueous solution made up of a weak acid and its salt (acid buffer) or a weak base and its salt (base buffer) (basic buffer).
When a tiny amount of strong acid or base is given to it, its pH varies very little, and it is thus used to keep a solution’s pH stable.
Buffer solutions are utilised in a variety of chemical processes. In nature, a buffer solution can be found in the form of blood.
The pH of human blood is 7.4 in its normal state. Many people suffer from extreme anxiety as well as alkalosis.
Alkalosis is a condition in which the blood pH is abnormally high. Acidosis is a condition in which the pH of the blood is greater than 7.4.
Some chemical reactions can only take place at a specific pH. Other household and consumer items, such as shampoo, must check their pH values to battle the soap’s alkalinity to avoid inflammation, baby lotion must maintain a pH of around 6 to prevent bacteria multiplication, washing powder, eye drops, fizzy lemonade, and so on.
Definition of the Buffer Solution
Buffers are solutions that have a steady concentration of hydrogen ions and hence have a pH that is almost independent of dilution and changes very little with minor additions of a strong acid or alkali.
A buffer solution, or simply a buffer, is a solution that avoids any pH change when a little amount of a strong acid or a strong base is applied to it. Acidity and alkalinity are balanced in both buffers.
When a tiny amount of a strong acid or a strong base is given to any substance, such as ammonium acetate, it tends to resist any change in its hydronium ion concentration or pH.
Buffer solutions are typically made up of a weak acid and salt with a strong base, such as CH3COOH and CH3COONa, or a weak base with a strong acid, such as NH4OH and NH4Cl, as well as salt.
Buffer Solution Preparation
To make a buffer solution with a varied pH, there are a few options. In the first way, make a solution with acid and its conjugate base by dissolving the acid component of the buffer in about 60% of the water used to make the final volume of solution.
Instead, check the pH of the solution with a pH detector. The pH can be altered to the appropriate value by using a strong base such as NaOH.
If a base and its conjugate acid are used to form the buffer, a strong acid, such as HCl, can be used to change the pH.
Once the pH is correct, dilute the solution to the final needed volume. You should also make solutions for both the acid type and the base form of the solution.
The amount of buffer in both solutions must be the same as in the final solution. To make the final buffer, add one solution to the other while keeping track of the pH.
Types of Buffer Solution
Buffer for Acid
An acid buffer is a buffer solution that contains high amounts of a weak acid and its salt with a strong base.
Such buffer solutions have a pH of less than 7 at 298 K, indicating that they are acidic. The pH of an acid buffer is determined by the equation.
pKa + ln = pH (Salt) Where Ka is the weak acid’s acid dissociation constant.
Buffer (Basic)
A simple buffer is a buffer solution that contains relatively large amounts of a weak base and its salt with a strong acid. These buffers have a pH of greater than 7 at 298 K, indicating that they are alkaline. NH4OH and NH4Cl, for example.
The equation pOH = pKb + ln determines the pH of an acceptable buffer (Salt)
Where Acid is the acid, and Kb is the base dissociation constant. Henderson equations are the name for these equations.
Acid Buffer Preparation
Using the Henderson-Hasselbalch Equation
Consider a weak acid (HA) and its salt (KA) in an acid buffer solution with a strong base (KOH). The weak acid HA ionises, and the equilibrium is as follows:
H+ + A ⇔HA + H2O
Ka = [H+] = acid dissociation constant [A–]/HA
Taking the RHS and LHS negative logs:
pKa + ([salt]/[acid]) = pH of acid buffer
The Henderson-Hasselbalch equation, sometimes known as the Henderson equation, is the equation in question.
Base Buffer Preparation
Consider a basic buffer solution with a strong acid and a weak base (B) and its salt (BA).
pOH can be calculated in the same way as before.
A basic buffer’s pOH is equal to pKb + log ([salt]/[acid]).
pKa – log ([salt]/[acid]) = pH of a basic buffer
The Henderson Equation’s Importance
The Henderson Equation can be applied to the following situations:
To Calculate the pH of the buffer made from a salt and a weak acid/base mixture.
To Determine the pKa value.
To Make a buffer solution with the required pH.
Henderson-Hasselbalch Equation Limitations
For strong acids and bases, the Henderson – Hasselbalch equation cannot be employed.
Capacity for Buffering
The buffer capacity is the number of millimoles of acid or base that must be supplied to a litre of buffer solution to adjust the pH by one unit.
(pH) B = millimoles
Conclusion
A buffer is an aqueous solution made up of a weak acid and its salt (acid buffer) or a weak base and its salt (base buffer) (basic buffer).
When a tiny amount of strong acid or base is given to it, its pH varies very little, and it is thus used to keep a solution’s pH stable.
Buffer solutions are utilised in a variety of chemical processes. In nature, a buffer solution can be found in the form of blood.
The pH of human blood is 7.4 in its normal state. Many people suffer from extreme anxiety as well as alkalosis.
Alkalosis is a condition in which the blood pH is abnormally high. Acidosis is a condition in which the pH of the blood is greater than 7.4.
