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 equivalence point depends on the nature of the acid and base involved in the titration.

2. How Does the Calculator Work?

The calculator uses different equations based on titration type:

Where:

• \( C \) — Concentration of the solution (mol/L)
• \( K_a \) — Acid dissociation constant
• \( K_b \) — Base dissociation constant
• \( pK_a = -\log K_a \)
• \( pK_b = -\log K_b \)

3. Importance of pH Calculation

Details: Accurate pH calculation at equivalence point is crucial for determining the endpoint in titrations, selecting appropriate indicators, and understanding the neutralization process in acid-base reactions.

4. Using the Calculator

Tips: Select the titration type, enter concentration in mol/L, and provide Kₐ or Kᵦ values for weak acid/base titrations. Concentration must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is pH = 7 for strong acid-strong base titration?
A: Because the salt formed undergoes neither hydrolysis nor dissociation, resulting in a neutral solution.

Q2: How does concentration affect pH at equivalence point?
A: For weak acid/base titrations, pH depends on concentration. Higher concentration leads to slightly different pH values due to the logarithmic relationship.

Q3: What are typical Kₐ values for common weak acids?
A: Acetic acid: 1.8×10⁻⁵, Formic acid: 1.8×10⁻⁴, Hydrocyanic acid: 4.9×10⁻¹⁰

Q4: Are there limitations to these calculations?
A: These are approximate calculations that assume ideal behavior and neglect activity coefficients and temperature effects.

Q5: How to select an appropriate indicator?
A: Choose an indicator whose pH range brackets the calculated equivalence point pH for accurate endpoint detection.