1. What is Dissociation Constant Calculator?

Definition: This calculator determines the dissociation constant (Kₐ) of a weak acid based on its initial concentration and degree of dissociation.

Purpose: It helps chemists and students quantify acid strength and understand acid-base equilibrium in solutions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( K_a \) — Acid dissociation constant (mol/m³)
• \( C_0 \) — Initial concentration of acid (mol/m³)
• \( \alpha \) — Degree of dissociation (0 to 1)

Explanation: The dissociation constant is calculated by multiplying the initial concentration by the square of the degree of dissociation.

3. Importance of Dissociation Constant

Details: The Kₐ value indicates acid strength - smaller values mean weaker acids that dissociate less in solution.

4. Using the Calculator

Tips: Enter the initial acid concentration and degree of dissociation (between 0 and 1). Both values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is degree of dissociation?
A: It's the fraction of acid molecules that dissociate into ions in solution (0 = no dissociation, 1 = complete dissociation).

Q2: What's a typical Kₐ value for weak acids?
A: Weak acids typically have Kₐ values between 10⁻² and 10⁻¹⁰ mol/m³.

Q3: Why do we square the degree of dissociation?
A: The square accounts for the equilibrium concentrations of both the hydrogen ion and conjugate base in the dissociation reaction.

Q4: Can I use molarity (mol/L) instead of mol/m³?
A: Yes, but be consistent with units. 1 M = 1000 mol/m³. The calculator will give Kₐ in the same units as C₀.

Q5: What if my degree of dissociation is very small?
A: For very small α values (less than 0.05), you can use the approximation Kₐ ≈ C₀ × α² without significant error.