AP Chemistry Flashcards: Acid-Base Reactions and Buffers
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 11 cards to help you master important concepts.
How does the reaction of a weak acid with a weak base differ from reactions involving at least one strong species?
A weak acid-weak base reaction does not run to completion; instead, it proceeds to an equilibrium state.
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How does the reaction of a weak acid with a weak base differ from reactions involving at least one strong species?
A weak acid-weak base reaction does not run to completion; instead, it proceeds to an equilibrium state.
What is the major species outcome if a weak base is in excess when reacting with a strong acid?
If the weak base is in excess, the resulting solution is a buffer, containing both the remaining weak base (B) and its newly formed conjugate acid (HB+).
Describe the reaction between a weak acid (HA) and a strong base (OH-).
The reaction, HA(aq) + OH−(aq) ⇌ A−(aq) + H2O(l), runs to completion, consuming the limiting reactant.
What is the net ionic equation for a strong acid-strong base reaction?
The net ionic equation is H+(aq) + OH−(aq) → H2O(l), as these reactions run to completion.
When is a buffer solution formed from a weak acid and strong base reaction?
A buffer is formed when the weak acid is in excess, resulting in a solution containing significant amounts of both the weak acid (HA) and its conjugate base (A−).
Describe the reaction between a weak base (B) and a strong acid (H3O+).
The reaction, B(aq) + H3O+(aq) ⇌ HB+(aq) + H2O(l), runs to completion, consuming the limiting reactant.
What determines the final pH of a solution after a strong acid and strong base reaction?
The final pH is determined by the concentration of the excess reactant (either H+ or OH−) after the neutralization reaction runs to completion.
Why is the solution at the equivalence point of a weak base-strong acid titration slightly acidic?
At the equivalence point, the solution contains the conjugate acid (HB+), which hydrolyzes water to produce H3O+, making the solution slightly acidic.
Write the general equilibrium equation for the reaction between a weak acid (HA) and a weak base (B).
The reaction between a weak acid and a weak base reaches an equilibrium represented by: HA(aq) + B(aq) ⇌ A−(aq) + HB+(aq).
Under what condition is the resulting solution acidic when a weak base is titrated with a strong acid?
The solution is acidic if the strong acid is the excess reactant, as its concentration will primarily determine the final pH.
Why is the solution at the equivalence point of a weak acid-strong base titration slightly basic?
At the equivalence point, the solution contains the conjugate base (A-), which hydrolyzes water to produce OH-, making the solution slightly basic.