Buffers Henderson-Hasselbalch Equation with One Equation One Unknown

The video tutorial explains the Henderson-Hasselbalch equation, focusing on calculating pH in a buffer system. It discusses the relationship between pKa and pH, especially when the concentrations of conjugate acid and base differ. The tutorial uses lactic acid as an example, illustrating the titration curve and how pH changes with the addition of sodium hydroxide. The video concludes with a calculation showing the pH is higher than the pKa due to the higher concentration of the conjugate base.

What happens to the pH when the concentrations of conjugate acid and base are not equal?

• The pH becomes zero.

• The pH becomes negative.

• The pH changes and is not equal to the pKa.

• The pH equals the pKa.

In the given problem, what is the pKa value of lactic acid?

• 1.00

• 5.00

• 4.56

• 3.86

What is the simpler type of Henderson-Hasselbalch problem discussed?

• Identifying the chemical structure.

• Determining the molecular weight.

• Calculating pH from given concentrations.

• Finding the pKa from pH.

What does the blue dot on the titration curve represent?

• The point where pH equals pKa.

• The initial state with no added sodium hydroxide.

• The maximum pH value.

• The endpoint of the titration.

What is the predominant species on the left side of the vertical line on the titration curve?

• Water

• Sodium hydroxide

• Lactate (A-)

• Lactic acid (HA)

What is the final calculated pH in the problem?

• 5.00

• 3.86

• 4.56

• 1.00

Why is the pH above the pKa in this problem?

• Because there is more conjugate acid.

• Because there is more conjugate base.

• Because the solution is neutral.

• Because the pKa is very high.