HSC Chemistry — Module 6
Buffers — Flashcards & Quiz
Buffer solutions resist pH change when small amounts of acid or base are added, and HSC Chemistry Module 6 uses them to test your conjugate-pair fluency. A buffer is a weak acid + its conjugate base (or vice versa). You need to apply the Henderson-Hasselbalch equation, identify effective buffer ranges, and link the concept to biological systems such as the bicarbonate buffer in blood plasma — a favourite exam context.
Sample Flashcards
Q1: What is a buffer solution and how does it work?
A buffer resists pH changes when small amounts of acid or base are added. It consists of a weak acid and its conjugate base (or weak base and conjugate acid). If H⁺ is added, the conjugate base neutralises it. If OH⁻ is added, the weak acid neutralises it.
Q2: Give an example of a biologically important buffer.
Blood uses the carbonate buffer system: H₂CO₃ ⇌ H⁺ + HCO₃⁻. It maintains blood pH at ~7.4. If H⁺ increases: HCO₃⁻ (base) neutralises it. If H⁺ decreases: H₂CO₃ (acid) releases more H⁺. This prevents dangerous pH swings that would denature enzymes.
Sample Quiz Questions
Q1: A buffer solution is made from a strong acid and its conjugate base.
Answer: FALSE
A buffer is made from a WEAK acid and its conjugate base (or a weak base and its conjugate acid). Strong acids fully dissociate and cannot form buffers.
Q2: The blood bicarbonate buffer system maintains blood pH at approximately 7.4.
Answer: TRUE
The H₂CO₃/HCO₃⁻ buffer system in blood absorbs excess H⁺ or OH⁻ to maintain the narrow pH range of 7.35-7.45 essential for enzyme function.
Related Concepts
Last updated: March 2026 · 2 flashcards · 2 quiz questions