1. What is pH at Equivalence Point?

The equivalence point in a titration is the point at which the amount of titrant added is exactly sufficient to completely neutralize the analyte solution. The pH at this point depends on the nature of the acid and base involved in the titration.

2. How Does the Calculator Work?

The calculator uses different formulas based on the acid-base combination:

Where:

• \( pKw \) — Negative logarithm of water ion product (typically 14.00)
• \( pKb \) — Negative logarithm of base dissociation constant
• \( C \) — Concentration of the salt formed at equivalence point (mol/L)

Explanation: For weak base-strong acid titrations, the equivalence point pH is acidic due to hydrolysis of the conjugate acid formed.

3. Importance of pH Calculation

Details: Accurate pH calculation at equivalence point is crucial for selecting appropriate indicators, understanding titration curves, and determining the endpoint of acid-base titrations.

4. Using the Calculator

Tips: Select the acid-base combination type. For weak base-strong acid titrations, provide pKw (typically 14.00), pKb of the weak base, and concentration of the resulting salt solution.

5. Frequently Asked Questions (FAQ)

Q1: Why is pH = 7 for strong acid-strong base titrations?
A: The salt formed from strong acid and strong base doesn't hydrolyze, resulting in a neutral solution with pH = 7.

Q2: What is the typical value of pKw?
A: pKw is typically 14.00 at 25°C, but it varies slightly with temperature.

Q3: How do I find the pKb value for a weak base?
A: pKb values are available in chemical reference tables or can be calculated from pKa of the conjugate acid (pKb = 14 - pKa).

Q4: Why is the equivalence point acidic for weak base-strong acid titrations?
A: The salt formed hydrolyzes to produce H⁺ ions, making the solution acidic at equivalence point.

Q5: Can this calculator be used for weak acid-strong base titrations?
A: No, this calculator specifically handles strong acid-strong base and weak base-strong acid combinations.