# Buffer problems and solutions

1. What is a buffer solution? Solution: A buffer solution is a solution that resists changes in pH when small quantities of an acid or a base are added.

2. How does a buffer solution work? Solution: A buffer solution works by using the equilibrium between an acid and its conjugate base (or a base and its conjugate acid). When an acid (or base) is added, it reacts with the conjugate base (or acid) to prevent a significant pH change.
3. What is the Henderson-Hasselbalch equation? Solution: The Henderson-Hasselbalch equation is pH = pKa + log([A⁻]/[HA]), where [A⁻] is the concentration of the base and [HA] is the concentration of the acid. It is used to calculate the pH of a buffer solution.
4. What are the components of a buffer solution? Solution: A buffer solution is made up of a weak acid and its conjugate base, or a weak base and its conjugate acid.
5. How can you prepare a buffer solution? Solution: A buffer solution can be prepared by mixing a weak acid with a salt of its conjugate base, or by mixing a weak base with a salt of its conjugate acid.
6. What is a common example of a buffer solution? Solution: An example of a buffer solution is acetic acid and sodium acetate.
7. What is the buffering capacity? Solution: Buffering capacity is a measure of the efficiency of a buffer in resisting changes in pH. It is greater when the concentrations of the acid and base are high and roughly equal.
8. What is the difference between an acidic buffer and a basic buffer? Solution: An acidic buffer has a pH less than 7 and is made from a weak acid and its conjugate base, while a basic buffer has a pH greater than 7 and is made from a weak base and its conjugate acid.
9. How does temperature affect a buffer solution? Solution: Temperature can affect the pH of a buffer solution as it can alter the equilibrium constant, Ka, for the weak acid or base.
10. How does a buffer solution maintain the pH of blood? Solution: The bicarbonate buffer system in blood, which involves the equilibrium between carbonic acid (H₂CO₃) and bicarbonate ion (HCO₃⁻), helps maintain a constant pH of around 7.4.
11. Why is the buffer capacity usually highest when pH=pKa? Solution: The buffer capacity is usually highest when pH=pKa because at this point the concentrations of the acid and its conjugate base are equal, which allows for optimal buffering.
12. What happens to the pH of a buffer solution when you add water? Solution: Adding water to a buffer solution should not change the pH because it does not alter the ratio of acid to base.
13. What happens when a strong acid is added to a buffer solution? Solution: When a strong acid is added to a buffer solution, it will react with the conjugate base present in the solution, leading to a small change in pH.
14. What happens when a strong base is added to a buffer solution? Solution: When a strong base is added to a buffer solution, it will react with the weak acid present in the solution, leading to a small change in pH.
15. How is buffer capacity related to concentration? Solution: The buffer capacity is directly related to the concentration of the buffer components. Higher concentrations of buffer components lead to higher buffer capacity.
16. What does pKa represent? Solution: pKa is the negative log of the acid dissociation constant (Ka). It is used to express the acidity of a solution.
17. What is the role of buffer solutions in biological systems? Solution: Buffer solutions in biological systems maintain a constant pH, which is crucial for many biological processes and the functioning of enzymes.
18. Can a buffer solution be made with a strong acid or base? Solution: A buffer solution cannot be made with a strong acid or base because they completely ionize in water, and do not establish the necessary equilibrium.
19. What is the isoelectric point? Solution: The isoelectric point (pI) is the pH at which a molecule carries no net electrical charge. For amino acids, the pI is typically determined by the average of the pKa values for the two ionizable groups.
20. What is an example of a physiological buffer? Solution: An example of a physiological buffer is the bicarbonate buffer system in blood, which maintains the blood pH close to 7.4.