1. What is Equivalence Point pH?

The equivalence point in a titration is the point where the amount of titrant added is exactly stoichiometrically equivalent to the amount of analyte present. The pH at this point depends on the nature of the acid and base being titrated.

2. How Does the Calculator Work?

The calculator uses different formulas based on titration type:

Where:

• \( pK_w \) — Water dissociation constant (14.00 at 25°C)
• \( pK_a \) — Acid dissociation constant of the weak acid

Explanation: For strong acid-strong base titrations, the salt formed is neutral. For weak acid-strong base titrations, the salt hydrolyzes to give a basic solution.

3. Importance of Equivalence Point pH

Details: Knowing the equivalence point pH is crucial for selecting appropriate indicators in acid-base titrations and understanding the nature of the titration curve.

4. Using the Calculator

Tips: Select the titration type and provide the pKa value if calculating for a weak acid-strong base titration. The calculator will automatically show/hide the appropriate input fields.

5. Frequently Asked Questions (FAQ)

Q1: What about weak base-strong acid titrations?
A: For weak base-strong acid titrations, pH = ½ pKw - ½ pKb at equivalence point.

Q2: Does temperature affect these calculations?
A: Yes, pKw changes with temperature. The standard value of 14.00 is for 25°C.

Q3: What if both acid and base are weak?
A: The equivalence point pH depends on the relative strengths of both and requires more complex calculation.

Q4: Are there exceptions to these rules?
A: Very concentrated solutions or non-aqueous solvents may require different calculations.

Q5: How accurate are these approximations?
A: They provide good estimates for most educational and practical purposes, though exact calculations may consider activity coefficients.