Use the Henderson–Hasselbalch equation to calculate the pH of each solution in Problem 29.

Verified step by step guidance

1. Identify the components of the buffer solution: the weak acid (HA) and its conjugate base (A^-).
2. Determine the concentrations of the weak acid [HA] and its conjugate base [A^-] in the solution.
3. Find the pKa of the weak acid. This is typically provided in a table or can be calculated from the Ka value using the formula: \( \text{pKa} = -\log(\text{Ka}) \).
4. Apply the Henderson–Hasselbalch equation: \( \text{pH} = \text{pKa} + \log\left(\frac{[A^-]}{[HA]}\right) \).
5. Substitute the values of pKa, [A^-], and [HA] into the equation to calculate the pH of the solution.

Key Concepts

Henderson-Hasselbalch Equation

The Henderson-Hasselbalch equation is a mathematical formula used to calculate the pH of a buffer solution. It relates the pH of the solution to the pKa (the negative logarithm of the acid dissociation constant) and the ratio of the concentrations of the conjugate base to the weak acid. The equation is expressed as pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the base and [HA] is the concentration of the acid.

Buffer Solutions

Buffer solutions are mixtures that can resist changes in pH upon the addition of small amounts of acid or base. They typically consist of a weak acid and its conjugate base or a weak base and its conjugate acid. Buffers are crucial in biological and chemical systems where maintaining a stable pH is essential for proper function and reactions.

pKa and Acid-Base Equilibrium

pKa is a measure of the strength of an acid in solution, representing the pH at which half of the acid is dissociated into its conjugate base. It is derived from the acid dissociation constant (Ka) and is crucial for understanding acid-base equilibria. A lower pKa value indicates a stronger acid, which is more likely to donate protons, influencing the pH of the solution and the effectiveness of buffers.