All Flashcards
What is the effect of adding a strong acid to a buffer solution?
The conjugate base in the buffer reacts with the added acid, neutralizing it and minimizing the change in pH.
What is the effect of adding a strong base to a buffer solution?
The weak acid in the buffer reacts with the added base, neutralizing it and minimizing the change in pH.
What is the effect of diluting a buffer solution?
The pH of the buffer remains relatively constant, as the ratio of [A-]/[HA] does not change significantly.
What happens when [A-] = [HA]?
The log term in the Henderson-Hasselbalch equation becomes zero, and pH = pKa, resulting in the strongest buffer action.
What happens when the concentrations of the acid or base exceed the buffer capacity?
The buffer's ability to resist pH changes is overwhelmed, and the pH changes significantly.
Define a buffer solution.
A solution that resists changes in pH, consisting of a weak acid and its conjugate base (or a weak base and its conjugate acid).
Define pH.
A measure of acidity, calculated as -log[H+].
Define pKa.
-log(Ka), which indicates the acid's strength. A lower pKa means a stronger acid.
Define Ka.
The acid dissociation constant, a measure of the strength of an acid in solution.
What is the conjugate base?
The species formed when an acid donates a proton (H+).
Steps to find pH of a buffer (directly stated).
- Calculate pKa. 2. Apply the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]).
Steps to find pH during a titration using the Henderson-Hasselbalch equation.
- Write the net ionic equation. 2. Use stoichiometry to determine the amounts of acid and conjugate base after the reaction. 3. Apply the Henderson-Hasselbalch equation.
How to calculate pKa from Ka?
pKa = -log(Ka)
How to determine the concentrations of acid and conjugate base after the addition of a base in a titration?
Use stoichiometry based on the balanced net ionic equation to determine the remaining moles of acid and the moles of conjugate base formed.
Steps to determine pH using ICE table.
- Set up an ICE (Initial, Change, Equilibrium) table. 2. Write the Ka expression. 3. Solve for [H+]. 4. Calculate pH = -log[H+].