1. What is Percent Dissociation?

Percent dissociation (α) represents the fraction of acid molecules that dissociate into ions in solution. It's a crucial parameter for understanding the strength and behavior of weak acids in aqueous solutions.

2. How Does the Calculator Work?

The calculator uses the percent dissociation formula:

Where:

• \( \alpha \) — Degree of dissociation (decimal)
• \( K_a \) — Acid dissociation constant
• \( C \) — Initial concentration of acid (M)

Explanation: This formula applies to weak acids where the degree of dissociation is small (α < 0.05). The percent dissociation is calculated by multiplying α by 100%.

3. Importance of Percent Dissociation

Details: Percent dissociation helps determine acid strength, predict solution pH, understand buffer capacity, and is essential in analytical chemistry and biochemical applications.

4. Using the Calculator

Tips: Enter the acid dissociation constant (Ka) and the initial concentration in molarity (M). Both values must be positive numbers. The calculator returns both decimal and percentage values.

5. Frequently Asked Questions (FAQ)

Q1: When is this formula valid?
A: This approximation is valid for weak acids where α < 0.05 (5% dissociation). For stronger dissociation, the exact quadratic equation should be used.

Q2: What are typical Ka values?
A: Strong acids have Ka > 1, weak acids have Ka between 10^-2 and 10^-10, and very weak acids have Ka < 10^-10.

Q3: How does concentration affect dissociation?
A: As concentration decreases, percent dissociation increases (dilution effect). This is why weak acids behave more like strong acids at very low concentrations.

Q4: What's the relationship between Ka and pKa?
A: pKa = -log(Ka). Lower pKa values indicate stronger acids, while higher pKa values indicate weaker acids.

Q5: Can this be used for bases?
A: For weak bases, a similar formula exists using Kb: α = √(Kb/C), where Kb is the base dissociation constant.