# Buffer solution concept questions and answers

1. What is a buffer solution?

A buffer solution is a solution that resists changes in pH when small amounts of an acid or a base are added. It maintains its pH nearly constant.

2. How do buffer solutions work?

Buffer solutions work by having a balance of a weak acid and its conjugate base (or a weak base and its conjugate acid). When additional acid or base is added to the solution, the buffer system can neutralize it, limiting changes to the pH.

3. What is the pH of a buffer solution made from a weak acid and its conjugate base?

The pH of a buffer solution made from a weak acid and its conjugate base can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A⁻]/[HA]), where [A⁻] is the concentration of the base and [HA] is the concentration of the acid.

4. What is the pKa of an acid?

The pKa of an acid is the negative logarithm of its acid dissociation constant (Ka). It indicates the acidity of the substance. The lower the pKa, the stronger the acid.

5. What is the purpose of a buffer solution in a biochemical system?

In biochemical systems, buffer solutions are used to maintain a stable pH environment. This is critical as biochemical reactions and processes are often pH-dependent.

6. What makes a good buffer solution?

A good buffer solution is one that has a capacity to resist changes in pH. This is usually achieved by having equal amounts of a weak acid and its conjugate base, or a weak base and its conjugate acid.

7. What is buffer capacity?

Buffer capacity is a measure of the efficiency of a buffer in resisting changes in pH. It is defined as the amount of an acid or a base that can be added to a volume of a buffer solution before its pH changes significantly (usually by one unit).

8. What happens to the pH of a buffer solution when you add water?

Adding water to a buffer solution does not change its pH. This is because the concentrations of the weak acid and its conjugate base (or the weak base and its conjugate acid) change proportionally, maintaining the ratio used in the Henderson-Hasselbalch equation.

9. How can you prepare a buffer solution?

A buffer solution can be prepared by mixing a weak acid with a salt of its conjugate base, or a weak base with a salt of its conjugate acid. Alternatively, a buffer can be made by partially neutralizing a weak acid with a strong base, or a weak base with a strong acid.

10. What is an acidic buffer?

An acidic buffer is a buffer solution made from a weak acid and its conjugate base. It has a pH less than 7.

1. What is a basic buffer?

A basic buffer is a buffer solution made from a weak base and its conjugate acid. It has a pH greater than 7.

1. What is the difference between a buffer solution and a neutral solution?

A buffer solution is a solution that resists changes in pH, due to the presence of a weak acid and its conjugate base or a weak base and its conjugate acid. A neutral solution, on the other hand, is simply a solution with a pH of 7, but it does not necessarily have the ability to resist changes in pH.

1. Can a strong acid or base be part of a buffer solution?

A strong acid or base is not typically part of a buffer solution because they completely dissociate in solution and do not contribute to the buffer’s ability to resist pH changes.

1. What are some examples of buffer solutions?

Examples of buffer solutions include blood (which contains a bicarbonate buffer system that maintains pH between 7.35 and 7.45), acetic acid and sodium acetate (an acidic buffer), and ammonia and ammonium chloride (a basic buffer).

1. What is the role of a buffer solution in a titration experiment?

In a titration experiment, a buffer solution can be used to maintain the pH at a nearly constant value. This is particularly useful in acid-base titrations where the pH changes can be abrupt.

1. What happens when a strong acid is added to a buffer solution?

When a strong acid is added to a buffer solution, the acid reacts with the weak base present in the buffer, producing its conjugate acid and water. This helps maintain the pH of the buffer.

1. What happens when a strong base is added to a buffer solution?

When a strong base is added to a buffer solution, the base reacts with the weak acid present in the buffer, producing its conjugate base and water. This helps maintain the pH of the buffer.

1. What happens to the buffer capacity as the amount of acid and base are equal?

The buffer capacity is highest when the concentrations of the weak acid and its conjugate base (or weak base and its conjugate acid) are equal. This is because the buffer has the maximum ability to neutralize added acid or base.

1. Why is a buffer solution important in the human body?

Buffer solutions are critical in the human body to maintain a constant pH. Many biological processes are sensitive to pH and work best at specific pH values. For example, blood is buffered to maintain a pH around 7.4.

1. Can a buffer solution have a pH of 7?

Yes, a buffer solution can have a pH of 7. This occurs when the concentrations of the weak acid and its conjugate base are equal, and the pKa of the weak acid is 7.