Buffers

Question 1

What is a “Buffer”?

Answer 1

A weak acid (HA) and its conjugated base pair (A-) or a weak base (B) and its conjugated acid pair (B+)

Question 2

What is the “Buffer range”?

Answer 2

pKa-1 < < pKa+1

Question 3

What is the “Buffer capacity”?

Answer 3

(The amount of acid of base the buffer can react with before giving a significant
pH change. Buffer capacity depends on the total concentration of the weak acid and its conjugate base in the solution)

1. Acid capacity: moles of H+ added to 1L buffer, causing a change in pH by -1
2. Base capacity: moles of OH- added to 1L buffer, causing a change in pH by +1

Question 4

What is the comparison of “acid and base capacity”?

Answer 4

1. Buffer capacity depends on the concentration and the ratio of the
   components
2. At 1:1 ratio, acid and base capacities are equal
   - (If the concentrations of the components are different, the acid and base capacity are not equal!)
3. If more salt is present (pH is above pKa), acid capacity is larger (the salt will react with the H+)
4. If more acid is present, (pH is blow pKa), base capacity is larger (the acid will react with the OH-)

Question 5

What is the pH of buffers: “The Henderson-Hasselbalch equation”?

Answer 5

pH = pKa + log [A-]/[HA]

Question 6

What is “Bicarbonate/carbonic acid”?

Answer 6

2. Extracellular
3. CO2 + H2O􏰀H2CO3
4. H2CO3 􏰀 HCO3- + H+
5. CO2 􏰀 HCO3- + H+
6. pH = pKa1 + log [HCO3-]/[CO2]

Question 7

What is the “effect of ventilation”?

Answer 7

1. Acidosis: hyperventilation

2. Alkalosis: hypoventilation

Question 8

What is the “Phosphate buffer” and the importance of it?

Answer 8

1. The most important intracellular buffer system
2. pH = 7.2 + log [HPO42-]/[H2PO4-]
3. on ATP, on the intracellular sugars, and their catabolic products

Importance: Buffering of blood pH is very important to stabilize it around 7.4
&
Small changes in pH can cause metabolic implications in human body like acidosis and alkalosis