Titration Calculator
Calculate titration endpoints and pH curves. Determine unknown concentrations from titration data.
Calculate pH at Volume
Key Points
25 mL
Equivalence Volume
8.73
pH at Equivalence
2.88
Initial pH
4.76
pH at Half-Eq. (= pKa)
Titration Curve

Buffer region: 2.5 - 22.5 mL (shaded green)

Indicator Recommendation

Phenolphthalein

pH range: 8.2 - 10

Color change: Colorless → Pink

All Indicators:

Methyl Orange(3.1-4.4)
Methyl Red(4.4-6.2)
Bromothymol Blue(6-7.6)
Phenol Red(6.8-8.4)
Phenolphthalein(8.2-10)
Thymol Blue(8-9.6)

Key Concepts

Equivalence: moles acid = moles base
Strong-Strong: pH = 7 at equivalence
Weak-Strong: pH > 7 at equivalence
Henderson-Hasselbalch: pH = pKa + log([A-]/[HA])
Half-equivalence: pH = pKa

Tips:

  • The buffer region is where pH changes slowly (green shaded area)
  • At half-equivalence, [HA] = [A-], so pH = pKa
  • Choose an indicator whose color change occurs near the equivalence pH

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