Buffer Capacity and pH

This video tutorial discusses buffer capacity, explaining how buffers maintain a stable pH within a certain range. It covers the ideal conditions for buffer capacity, emphasizing the importance of the conjugate acid and base concentrations being within a factor of 10. The video also explains how to choose the right weak acid for a buffer by ensuring the pKa is within one unit of the desired pH. The Henderson-Hasselbalch equation is introduced to calculate the ratio of base to acid, and an example problem is solved to demonstrate the process.

What happens when a buffer's capacity is exceeded?

• The buffer becomes more concentrated.

• There is a significant change in pH.

• The buffer solution evaporates.

• The pH remains constant.

What is the ideal condition for a buffer's capacity?

• When the acid concentration is double the base concentration.

• When the buffer is diluted.

• When the conjugate acid and base concentrations are equal.

• When the base concentration is ten times the acid concentration.

How should the pH of a buffer compare to the pKa of a weak acid?

• The pH should be within one unit of the pKa.

• The pH should be unrelated to the pKa.

• The pH should be exactly double the pKa.

• The pH should be half of the pKa.

What is the first step in creating a buffer with a specific pH?

• Select a weak acid with a pKa within one unit of the desired pH.

• Mix equal parts of acid and base.

• Choose a strong acid.

• Calculate the buffer's capacity.

In the example problem, what is the target pH for the buffer?

• pH of 6

• pH of 3

• pH of 5

• pH of 4

How is the Ka value calculated if the pKa is known?

• By adding 10 to the pKa.

• By raising 10 to the power of negative pKa.

• By multiplying the pKa by 10.

• By dividing the pKa by 10.

Which acid was chosen in the example problem for a buffer with a pH of 4?

• Acetic acid

• Hydrochloric acid

• Citric acid

• Sulfuric acid

What is the calculated ratio of base to acid in the example problem?

• 4:1

• 2:1

• 3.5:1

• 1:1

What equation is used to solve for the ratio of base to acid?

• Boyle's law

• Henderson-Hasselbalch equation

• Avogadro's law

• Arrhenius equation

What is the significance of the base to acid ratio in buffer solutions?

• It has no effect on the buffer's properties.

• It determines the color of the solution.

• It changes the temperature of the solution.

• It affects the buffer's ability to maintain pH.