The Four Types
| Titration | Start pH | Equiv. Pt pH | Sharp Jump? |
|---|---|---|---|
| SA+SB | ~1 | = 7 | Very sharp |
| WA+SB | ~3 | > 7 | Moderate |
| SA+WB | ~1 | < 7 | Moderate |
| WA+WB | ~3 | ≈ 7 | Gradual |
pH Curves (Adding Base to Acid)
Half-Equivalence Point
At half-equivalence, [HA] = [A⁻], so pH = pKa. This can be read from the buffer region of WA+SB curves.
📋 Exam Tip
The buffer region is the flat section before equivalence in WA+SB curves. The WA+WB curve has no sharp equivalence jump, making it unsuitable for indicator use.