1. What is Henderson's Equation for Acidic Buffers?

Definition: Henderson's equation relates the pH of an acidic buffer solution to the concentrations of the weak acid and its conjugate base (salt).

Purpose: It helps chemists and biochemists calculate the required salt concentration to achieve a specific pH in a buffer solution.

2. How Does the Calculator Work?

The calculator uses Henderson's equation:

Where:

• \( C_{salt} \) — Concentration of salt (mol/m³)
• \( C_{acid} \) — Concentration of acid (mol/m³)
• \( pH \) — Negative log of hydronium ion concentration
• \( pK_a \) — Negative log of acid ionization constant

Explanation: The equation shows how the ratio of salt to acid concentrations determines the pH of a buffer solution.

3. Importance of Buffer Calculations

Details: Accurate buffer preparation is crucial in biological systems, chemical experiments, and industrial processes where maintaining stable pH is essential.

4. Using the Calculator

Tips: Enter the acid concentration (mol/m³), desired pH, and the pK_a of the acid. All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a buffer solution?
A: A solution that resists pH change when small amounts of acid or base are added, typically containing a weak acid and its conjugate base.

Q2: How do I find the pK_a of an acid?
A: pK_a values are tabulated in chemistry references or can be calculated from the acid's ionization constant (K_a).

Q3: What units should I use for concentration?
A: The calculator uses mol/m³, but you can convert from mol/L (M) by multiplying by 1000 (1 M = 1000 mol/m³).

Q4: Does this work for all pH values?
A: Henderson's equation is most accurate when pH is within ±1 unit of the pK_a (effective buffer range).

Q5: Can I use this for basic buffers?
A: No, this calculator is specifically for acidic buffers. Basic buffers require a different form of Henderson's equation.