Buffers and titrations
What students will learn
Identify the species left after reacting amounts, then explain buffer response and titration curves with the model appropriate to each region.
Before this topic
- Moles, limiting amounts and final solution volume
- Conjugate-pair equilibria, pH and pKa
- Titration equivalence versus endpoint
Read and connect
Supporting reading: Introduction to Titration →
Revisit delivered volume, reacting proportions and endpoint bias before reading a pH titration curve.
Read: Acid-Base Reactions and Buffers →
React amounts first, identify major remaining species, and then select an equilibrium or excess-ion model.
Read: Properties of Buffers →
Explain how both weak conjugate forms consume small additions and why buffering has finite limits.
Read: Henderson-Hasselbalch Equation →
Calculate the current pH of an established buffer from a justified base/acid ratio.
Read: Buffer Capacity →
Separate ratio-controlled pH from total and directional capacity; compare controlled equal-volume samples.
Read: Acid-Base Titrations →
Interpret weak/strong and resolved polyprotic titration regions through stoichiometry, major species and half-step pKa.
Supporting reading: pH and pKa →
Apply dominant-form reasoning to indicator choice in the steep titration region.
Supporting reading: Introduction to Solubility Equilibria →
Later solubility connection: review the free-ion quotient before coupling an imposed pH to dissolution.
Before this connection: Chemical equilibrium: dissolution equations, Q versus K, and molar solubility.
Supporting reading: Common-Ion Effect →
Contrast buffer proton-transfer effects with an explicit common-ion source.
Before this connection: Chemical equilibrium: dissolution equations, Q versus K, and molar solubility.
Supporting reading: pH and Solubility →
Connect a buffered pH environment to free-ion removal and conditional total solubility.
Before this connection: Chemical equilibrium: dissolution equations, Q versus K, and molar solubility.
Check understanding
Use the complete prompt to make student reasoning visible, then consult the separate worked reasoning and criteria. A reading completion tick records reading history.
Interpret a weak-acid titration and compare equivalence species →
Find initial concentration and pKa, identify major species, explain basic weak-acid equivalence and a delivery-tip bubble bias; then compare weak-base and strong/strong equivalence.
Complete supplied titration data and assumptions are in the prompt. The accompanying model supports interpretation; it does not establish a completed laboratory investigation.
Explain how a buffer responds to added acid and base →
Choose an effective weak conjugate pair, write both proton-transfer reactions and explain a finite rather than perfectly fixed pH response.
The response is qualitative; this does not add an excluded numerical buffer pH-change calculation.
Compare buffer capacity at equal starting pH →
Separate pair ratio from reservoir amounts, identify directional capacity and trace accidental dilution through a controlled comparison.
Capacity reasoning uses supplied component amounts; the fixed-concentration interactive model does not establish capacity scaling.
Standards and earlier reading lists
These topic placements organize reading. Edition-qualified Standards mappings and the existing complete unit task sets retain their reviewed scope.