Buffers

Question 1

What is a buffer solution?

Answer 1

A solution that contains components that resist the change in pH of a solution after a acid or base is added to it.

Question 2

What are the uses of buffers?

Answer 2

1. Physiological:
   * Enzymes function only at optimum pH levels, their structure gets denatured when the pH fluctuates.
   * Blood is a natural buffer with a pH of 7.8. This is the ideal pH for transportation of oxygen.
2. Chemical:
   * Used in chemical laboratories to maintain optimum pH levels for chemical reactions.
3. Industrial:
   * Fermentation
   * Setting optimum conditions for dyes in coloring fabrics.
   * Commercial products require optimum conditions to maintain product behavior.

Question 3

What are the buffering agents in blood?

Answer 3

H2CO3 and HCO3-

Question 4

What is acid dissociation constant?

Answer 4

It measures how strong or weak the acid is.

Question 5

True or False: Larger the pKa, stronger the acid.

Answer 5

False.

Question 6

State Le Chatelier’s principle.

Answer 6

An equilibrium system in stress will shift its equilibrium position to undo the stress.

Question 7

What is the composition of a buffer?

Answer 7

1. Weak acid and its conjugate base.
2. Weak base and its conjugate acid.

Question 8

What is the basis of working of a buffer?

Answer 8

• The equilibrium established between a weak acid and its conjugate base or a weak base and its conjugate acid.
• Buffers act as neutralizing agents because they contain both positive and negative ions.

Question 9

What is the Henderson-Hasselbalch equation used for?

Answer 9

Determining the pH of a buffer solution.

Question 10

What is buffer capacity?

Answer 10

The minimum amount of acid or base that must be added to 1L of the solution to change its pH by 1 unit.

Question 11

What determines the buffer capacity of a solution?

Answer 11

1. The concentration of weak acid determines the buffer capacity against a base.
2. The concentration of conjugate base determines the buffer capacity against an acid.

Question 12

When is the buffer capacity maximum?

Answer 12

The buffer capacity is maximum when pH= pKa.
When the concentration of weak acid= conjugate base.
This is because the buffer can resist acid and base equally.

Question 13

What are the criteria for the creation of a buffer solution?

Answer 13

1. Sufficient concentration- Concentration has to be between 0-200 mM.
2. pH of the solution must be within one unit of the pKa of the acid.