3.1.12.4 Buffer Solutions

• What is a buffer solution?

  Aqueous solution resists pH changes
• The purpose of buffer solutions is to maintain a stable pH.

  True
• The Henderson-Hasselbalch equation is used to calculate the pH of a buffer solution.

  True
• Steps to calculate the pH of a buffer solution using the Henderson-Hasselbalch equation:

  1️⃣ Determine the pKa of the weak acid

  2️⃣ Identify the concentrations of the weak acid and its conjugate base

  3️⃣ Substitute the values into the Henderson-Hasselbalch equation

  4️⃣ Calculate the pH
• Buffer solutions resist changes in pH
• A buffer solution can contain a weak base and its conjugate acid
• Acetic acid reacts with added base to form acetate, while acetate reacts with added acid to form acetic acid.


  True
• Match the term with its description:

  pH ↔️ Hydrogen ion concentration

  pKa ↔️ Negative logarithm of Ka

  [Conjugate Base] ↔️ Molar concentration of the conjugate base

  [Weak Acid] ↔️ Molar concentration of the weak acid
• Match the buffer system with its components:

  Acetic acid/Acetate ↔️ Acetic acid (CH₃COOH) and Acetate (CH₃COO^-)

  Ammonia/Ammonium ↔️ Ammonia (NH₃) and Ammonium (NH₄⁺)

  Carbonic acid/Bicarbonate ↔️ Carbonic acid (H₂CO₃) and Bicarbonate (HCO₃^-)
• The conjugate base of acetic acid is acetate
• A buffer solution resists changes in pH when small amounts of acid or base are added.

  True
• A weak acid in a buffer solution neutralizes excess OH^- ions.


  True
• What is the purpose of the Henderson-Hasselbalch equation?

  Calculate the pH
• What does the pKa term in the Henderson-Hasselbalch equation represent?

  -log₁₀(Ka)
• Steps to calculate the pH of a buffer solution using the Henderson-Hasselbalch equation

  1️⃣ Identify the pKa of the buffer system

  2️⃣ Determine the concentrations of the conjugate base and weak acid

  3️⃣ Plug the values into the Henderson-Hasselbalch equation

  4️⃣ Calculate the pH
• The composition of a buffer solution includes a weak acid and its conjugate base
• The pH of a buffer solution is typically close to the pKa
• The Henderson-Hasselbalch equation is given by pH = pKa + log₁₀([Conjugate Base] / [Weak Acid])
• What is the role of a weak acid in a buffer solution?

  Neutralize excess OH^- ions
• The pH of a buffer solution is typically close to the pKa of the weak acid or base.


  True
• What is an example of a weak acid used in a buffer solution?

  Acetic acid
• What is the Henderson-Hasselbalch equation used to calculate?

  pH of a buffer solution
• By adjusting the ratio of conjugate base to weak acid, the pH of a buffer solution can be maintained close to the pKa value.
• The carbonic acid/bicarbonate buffer system uses carbonic acid and bicarbonate ions.
• What is the conjugate acid of ammonia?

  Ammonium
• The pH range of a buffer solution is close to the pKa
• The Henderson-Hasselbalch equation is used to calculate the pH
• The Henderson-Hasselbalch equation is expressed as pH = pKa + log₁₀([Conjugate Base]/[Weak Acid]).
• The pH in the Henderson-Hasselbalch equation is the hydrogen ion concentration in the solution.
• What happens to the pH of a buffer solution when the ratio of conjugate base to weak acid is adjusted?

  It changes
• Match the buffer system with its weak acid/base and conjugate pair:

  Acetic acid/Acetate ↔️ CH₃COOH/CH₃COO^-

  Ammonia/Ammonium ↔️ NH₃/NH₄⁺

  Carbonic acid/Bicarbonate ↔️ H₂CO₃/HCO₃^-

  Phosphoric acid/Phosphate ↔️ H₃PO₄/PO₄^3-
• In the acetic acid/acetate buffer system, sodium acetate is an example of the conjugate base.


  True
• Buffer solutions are used in the food and beverage industry to ensure consistent taste and texture.


  True
• What is the pH range of a buffer solution typically close to?

  pKa
• Match the buffer component with its example:

  Weak Acid ↔️ Acetic acid (CH₃COOH)

  Conjugate Base ↔️ Sodium acetate (CH₃COONa)

  Weak Base ↔️ Ammonia (NH₃)

  Conjugate Acid ↔️ Ammonium chloride (NH₄Cl)
• What does pKa represent in the Henderson-Hasselbalch equation?

  -log₁₀(Ka)
• What is the role of a weak base in a buffer solution?

  Neutralize excess H⁺ ions
• A buffer solution can contain a weak acid and its conjugate base
• What is an example of a conjugate base used in a buffer solution?

  Sodium acetate
• The Henderson-Hasselbalch equation is $pH =$$pKa +$$\log_{10} \left( \frac{[\text{Conjugate Base}]}{[\text{Weak Acid}]} \right)$, where pKa is the negative logarithm of the acid dissociation constant.