Buffers: Understanding Buffer Solutions and Their Importance

Question 1

Which of the following is not a characteristic of a buffer solution?

Accepted Answer

Can completely neutralize strong acids or bases

Answer

Stable pH despite small additions of acid or base

Answer

Made up of a weak acid and its conjugate base or a weak base and its conjugate acid

Answer

Resists pH changes

Question 2

What is the primary purpose of the Henderson-Hasselbalch equation?

Accepted Answer

Calculating the pH of a buffer solution

Answer

Determining the concentration of a weak acid or base

Answer

Predicting the buffer capacity of a solution

Answer

Identifying the conjugate acid-base pair in a buffer solution

Question 3

A buffer solution with a pH of 5 contains a 0.1 M concentration of a weak acid. What is the approximate concentration of its conjugate base?

Accepted Answer

0.01 M

Answer

0.1 M

Answer

0.001 M

Answer

1 M

Question 4

What is the primary role of a buffer in a chemical reaction?

Accepted Answer

Stabilizing the pH of the solution

Answer

Preventing the formation of a precipitate

Answer

Acting as a catalyst

Answer

Absorbing heat

Question 5

What is the purpose of the Henderson-Hasselbalch equation?

Accepted Answer

To calculate the pH of buffer solutions

Answer

To determine the concentration of a weak acid

Answer

To predict the direction of a chemical reaction

Answer

To measure the strength of a buffer

Question 6

A buffer solution with a pH of 7 contains equal concentrations of which of the following?

Accepted Answer

Weak acid and its conjugate base

Answer

Strong acid and strong base

Answer

Weak base and its conjugate acid

Answer

Salt and water

Question 7

Which of the following is NOT a common buffer system?

Accepted Answer

Hydroxide buffer

Answer

Acetate buffer

Answer

Phosphate buffer

Answer

Carbonate buffer

Question 8

How does the addition of a strong acid to a buffer solution affect its pH?

Accepted Answer

Decreases pH

Answer

Increases pH

Answer

No change in pH

Answer

Depends on the concentration of the strong acid

Question 9

What is the primary purpose of the Henderson-Hasselbalch equation?

Accepted Answer

To calculate the pH of buffer solutions using the concentrations of the weak acid and its conjugate base

Answer

To predict the reaction between an acid and a base

Answer

To determine the buffer capacity of a particular buffer system

Answer

To measure the amount of acid or base added to a buffer solution

Question 10

Which of the following factors does NOT affect the buffer capacity of a solution?

Accepted Answer

Volume of the solution

Answer

Concentrations of the weak acid and its conjugate base

Answer

Temperature

Answer

Strength of the weak acid

Question 11

Which of the following will cause a decrease in the pH of a buffer solution?

Accepted Answer

Adding more conjugate acid

Answer

Adding more conjugate base

Answer

Diluting the buffer

Answer

Increasing the temperature

Question 12

What is the limiting reactant in a reaction between 20.0 mL of 0.20 M acetic acid and 25.0 mL of 0.25 M sodium acetate?

Accepted Answer

Acetic acid

Answer

Sodium acetate

Answer

Neither (reaction goes to completion)

Answer

Cannot be determined without an equilibrium constant

Question 13

Which of the following is a suitable weak base for creating a buffer solution with a pH around 8?

Accepted Answer

Ammonia

Answer

Sodium hydroxide

Answer

Acetic acid

Answer

Nitric acid

Question 14

Which of the following is a defining characteristic of a buffer solution?

Accepted Answer

Resists changes in pH when small amounts of acid or base are added

Answer

Has a high concentration of acid and a low concentration of base

Answer

Has a low concentration of acid and a high concentration of base

Answer

Is formed when a strong acid is added to a weak base

Question 15

What is the relationship between the pKₐ of a weak acid and the pH of a buffer solution made from that acid and its conjugate base?

Accepted Answer

The pH of the buffer solution is equal to pKₐ + log[conjugate base]/[weak acid]

Answer

The pKₐ is equal to the pH of the buffer solution

Answer

The pH of the buffer solution is equal to the pKₐ

Answer

The pH of the buffer solution is equal to pKₐ - log[conjugate base]/[weak acid]

Question 16

What is the primary purpose of using a buffer in a chemical reaction?

Accepted Answer

To prevent significant changes in pH

Answer

To increase the reaction rate

Answer

To decrease the reaction rate

Answer

To catalyze the reaction

Question 17

What is the conjugate base of acetic acid?

Accepted Answer

Acetate ion

Answer

A strong acid

Answer

A strong base

Answer

A neutral compound

Question 18

What is buffer capacity, and how does it contribute to maintaining the pH stability of a buffer solution when small amounts of acid or base are added?

Accepted Answer

Buffer capacity is the ability of a buffer solution to resist significant pH changes upon the addition of small amounts of acid or base.

Answer

Buffer capacity is the pH of a buffer solution at a specific temperature.

Answer

Buffer capacity is the same for all buffer solutions.

Answer

Buffer capacity has no impact on the pH of a buffer solution.

Question 19

Describe the crucial role of buffers in preserving pH stability within biological systems. Provide specific examples of how buffers are employed to maintain optimal cellular functions.

Accepted Answer

Buffers stabilize pH in the bloodstream, protecting enzymes and proteins from potentially harmful pH changes.

Accepted Answer

Buffers help maintain proper pH levels in the stomach, aiding in the efficient digestion of food.

Accepted Answer

Buffers regulate pH in the lungs, facilitating efficient gas exchange during respiration.

Question 20

Which of the following is a defining characteristic of a buffer solution?

Accepted Answer

Resists changes in pH

Answer

Contains a weak base and its conjugate acid

Answer

Has a low buffering capacity

Answer

Can neutralize large amounts of added acid or base

Question 21

The Henderson-Hasselbalch equation is primarily used to calculate the:

Accepted Answer

pH of a buffer solution

Answer

Buffer capacity

Answer

Equilibrium constant of a buffer solution

Answer

Solubility product of a precipitate

Question 22

Which of the following is a common weak acid used in the preparation of buffer solutions?

Accepted Answer

Acetic acid

Answer

Hydrochloric acid

Answer

Sulfuric acid

Answer

Nitric acid

Question 23

Which of the following is an example of a biological buffer system?

Accepted Answer

Carbonic acid-bicarbonate buffer system

Answer

Phosphate buffer system

Answer

Acetate buffer system

Answer

Ammonia buffer system

Question 24

The primary purpose of using a buffer solution in a laboratory setting is to:

Accepted Answer

Maintain a relatively constant pH

Answer

Neutralize acids or bases

Answer

Calibrate pH meters

Answer

Extract organic compounds

Question 25

In a buffer solution with a pH of 4.5, which of the following species is present in the highest concentration?

Accepted Answer

CH3COO-

Answer

H+

Answer

OH-

Answer

CH3COOH

Question 26

Which component is NOT present in a buffer solution?

Accepted Answer

Strong acid

Answer

Weak acid

Answer

Weak base

Answer

Salt

Question 27

What is the primary function of a buffer solution?

Accepted Answer

To stabilize pH

Answer

To donate protons

Answer

To act as a strong electrolyte

Answer

To neutralize acids or bases

Question 28

Which component is NOT found in a buffer solution?

Accepted Answer

Strong acid or strong base

Answer

Weak acid or weak base

Answer

Salt of the weak acid or weak base

Question 29

Which of the following is NOT a defining characteristic of buffers?

Accepted Answer

They are highly concentrated solutions.

Answer

They resist changes in pH.

Answer

They contain a weak acid and its conjugate base.

Answer

They have a finite capacity to buffer an excess of acid or base.

Question 30

What is the primary purpose of the Henderson-Hasselbalch equation?

Accepted Answer

To calculate the pH of a buffer solution.

Answer

To determine the concentration of a strong acid.

Answer

To determine the equilibrium constant of a reaction.

Answer

To predict the direction of a chemical reaction.

Question 31

What is the primary role of a weak acid in a buffer system?

Accepted Answer

To neutralize added strong base.

Answer

To decrease the pH of the solution.

Answer

To increase the pH of the solution.

Question 32

Which of the following solutions has the highest buffer capacity?

Accepted Answer

A solution with approximately equal concentrations of weak acid and its conjugate base.

Answer

A solution with a high concentration of conjugate base.

Answer

A solution with a high concentration of weak acid.

Question 33

What is the expected change in pH of a buffer solution when a small amount of strong acid is added?

Accepted Answer

It decreases.

Answer

It increases.

Answer

It remains the same.

Answer

It becomes unpredictable.

Question 34

What is the expected change in pH of a buffer solution when a small amount of strong base is added?

Accepted Answer

It increases.

Answer

It decreases.

Answer

It remains the same.

Answer

It becomes unpredictable.

Question 35

What is the conjugate base of H2CO3?

Accepted Answer

HCO3-

Answer

CO2

Answer

H3O+

Answer

CO32-

Question 36

Which of the following solutions would have the highest buffer capacity?

Accepted Answer

0.5 M CH3COOH / 0.5 M CH3COONa

Answer

0.1 M CH3COOH / 0.1 M CH3COONa

Answer

1.0 M HCl / 1.0 M NaCl

Answer

0.1 M NH3 / 0.1 M NH4Cl

Question 37

Which of the following factors does NOT affect the pH of a buffer solution?

Accepted Answer

Temperature

Answer

Concentration of the weak acid

Answer

Concentration of the conjugate base

Question 38

What is the name of the equation used to calculate the pH of a buffer solution?

Accepted Answer

Henderson-Hasselbalch equation

Answer

Bronsted-Lowry equation

Answer

Debye-Hückel equation

Answer

Arrhenius equation

Question 39

Which of the following is a property of buffers?

Accepted Answer

Maintain a relatively constant pH

Answer

Can undergo redox reactions

Answer

Exhibit low conductivity

Answer

React completely with strong acids or bases

Question 40

What is the primary purpose of the Henderson-Hasselbalch equation?

Accepted Answer

To calculate the pH of a buffer solution

Answer

To determine the concentration of a strong acid

Answer

To measure the buffer capacity

Answer

To predict the reaction of a buffer with a weak acid

Question 41

Which of the following factors primarily affects the buffer capacity of a solution?

Accepted Answer

Concentrations of the weak acid and its conjugate base

Answer

Temperature

Answer

Pressure

Question 42

Which of the following actions will increase the pH of a buffer solution?

Accepted Answer

Adding a strong base

Answer

Increasing the temperature

Answer

Adding a strong acid

Answer

Adding water

Question 43

What is the general relationship between the pKa of a weak acid and the pH of its buffer solution?

Accepted Answer

The pH is approximately equal to the pKa

Answer

The pH is always higher than the pKa

Answer

The pH is always lower than the pKa

Question 44

Which of the following actions DOES NOT describe a function of a buffer solution?

Accepted Answer

Drastically change the pH

Answer

Act as an electrolyte

Answer

Resist changes in pH

Answer

Maintain a specific pH range

Question 45

What is the formula used to calculate the pH of a buffer solution?

Accepted Answer

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

Answer

Kb = [OH-][BH+][B]

Answer

pH = [H+][OH-]

Answer

Ka = [H+][A-]/[HA]

Question 46

A buffer solution contains 0.10 M acetic acid (pKa = 4.76) and 0.15 M sodium acetate. What is its pH?

Accepted Answer

4.90

Answer

5.50

Answer

4.60

Answer

5.20

Question 47

What is the conjugate base of a weak acid?

Accepted Answer

The ion formed when the weak acid loses a proton (H+)

Answer

The weak acid itself

Answer

The ion formed when the weak acid gains a proton (H+)

Answer

Water

Question 48

Which of the following is considered a buffer solution?

Accepted Answer

A mixture of a weak acid and its salt

Answer

A solution of a strong base

Answer

Pure water

Answer

A solution of a strong acid

Question 49

To create a buffer solution with a specific pH, what's the most effective approach?

Accepted Answer

Use the Henderson-Hasselbalch equation to determine the correct ratio of weak acid to conjugate base

Answer

Add an equal amount of weak acid and conjugate base

Question 50

What is the main function of a buffer solution within a biological system?

Accepted Answer

To maintain a stable pH

Answer

To transport molecules across cell membranes

Answer

To regulate gene expression

Answer

To provide energy for cellular processes

Question 51

What is a limitation of buffer solutions?

Accepted Answer

They are effective only against small changes in pH

Answer

They are expensive to prepare

Answer

They are not stable over time

Answer

They can be toxic to cells