Buffer Solutions and Equations

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Questions and Answers

Which of the following mixtures would NOT form a buffer solution?

Acetic acid (CH3COOH) and sodium acetate (CH3COONa)
Ammonia (NH3) and ammonium chloride (NH4Cl)
Hydrochloric acid (HCl) and sodium chloride (NaCl) (correct)
Formic acid (HCOOH) and sodium formate (HCOONa)

What is the pH of a buffer solution prepared by mixing 0.1 M acetic acid (CH3COOH) and 0.1 M sodium acetate (CH3COONa)? The pKa of acetic acid is 4.74.

6.74
3.74
5.74
4.74 (correct)

What is the purpose of a buffer solution?

To decrease the pH of a solution
To maintain the pH of a solution relatively constant (correct)
To increase the pH of a solution
To accelerate the rate of a chemical reaction

A buffer solution with a higher concentration of the weak acid compared to its conjugate base will be more effective at:

Neutralizing a strong base (A) Signup and view all the answers

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

The volume of the solution (B) Signup and view all the answers

A buffer solution is prepared by mixing a weak acid and its conjugate base. What happens to the pH of the buffer if you add a small amount of strong acid?

The pH will remain relatively constant. (C) Signup and view all the answers

A buffer solution is prepared with a weak acid and its conjugate base. Which of the following statements accurately describes the relationship between the pH of the buffer and the pKa of the weak acid?

The pH of the buffer is determined by the ratio of the conjugate base to the weak acid, and it can be equal to, higher than, or lower than the pKa, depending on this ratio. (C) Signup and view all the answers

A buffer solution containing a weak acid and its conjugate base is prepared. How does the buffer capacity change if the concentration of both the weak acid and the conjugate base are doubled?

The buffer capacity increases. (D) Signup and view all the answers

Two buffer solutions are prepared, both containing the same weak acid but at different concentrations. One buffer has a high concentration of the weak acid and its conjugate base, while the other has a low concentration. Which of these statements is true regarding the buffer capacity of these solutions?

The buffer with the higher concentration will have a higher buffer capacity. (D) Signup and view all the answers

Which of the following examples is NOT a characteristic of a buffer solution?

Adding a strong acid to a buffer solution will result in a significant increase in pH. (A) Signup and view all the answers

Match the following buffer solution components with their corresponding roles in maintaining pH:

Weak acid = Donates protons (H+) when the pH rises Conjugate base = Accepts protons (H+) when the pH falls Buffer capacity = The ability to resist pH changes Henderson-Hasselbalch equation = Calculates the pH of a buffer Signup and view all the answers

Match the following factors with their impact on buffer capacity:

Concentration of buffer components = Higher concentration enhances capacity Ratio of conjugate acid/base = Determines effectiveness towards acids or bases Dilution of buffer = Reduces capacity pKa of the weak acid = Affects the pH range where the buffer is effective Signup and view all the answers

Match the following terms with their corresponding definitions:

Buffer solution = A mixture of a weak acid and its conjugate base or a weak base and its conjugate acid pH = A measure of the acidity or basicity of a solution pKa = The negative logarithm of the acid dissociation constant (Ka) of a weak acid Conjugate acid-base pair = A pair of chemical species that differ by a single proton (H+) Signup and view all the answers

Match the following applications with their corresponding reasons for using buffer solutions:

Blood pH regulation = Maintains a stable environment for biological processes Enzyme reactions = Provides optimal pH for enzyme activity Chemical analysis = Provides a stable pH for precise measurements Drug delivery = Maintains pH stability for drug effectiveness Signup and view all the answers

Match the following scenarios with their corresponding impact on a buffer solution:

Adding a strong acid = The conjugate base of the buffer reacts with the acid, consuming it and minimizing pH change Adding a strong base = The weak acid of the buffer reacts with the base, consuming it and minimizing pH change Increasing the concentration of the weak acid = Increases the buffer's effectiveness towards absorbing base Decreasing the concentration of the conjugate base = Decreases the buffer's effectiveness towards absorbing acid Signup and view all the answers

Flashcards

Buffer Solution

A mixture of a weak acid and its conjugate base or a weak base and its conjugate acid that resists pH changes.

Henderson-Hasselbalch Equation

An equation to calculate pH of a buffer: pH = pKa + log([conjugate base]/[weak acid]).

pKa

The negative logarithm of the acid dissociation constant (Ka); indicates strength of the acid.

Buffer Capacity

The ability of a buffer to neutralize acids or bases without significant pH change, dependent on component concentrations.