Activity Coefficient Calculator
Calculate activity coefficients for ionic solutions using Debye-Hückel theory and ionic strength.
Enter Solution Data
Å
Common values: H⁺ (9), Na⁺ (4), K⁺ (3), Cl⁻ (3), OH⁻ (3.5)
Ion Concentrations
Results
Enter solution data to calculate activity coefficient
Activity Coefficient Theory
Debye-Hückel Equation
log γ = -A z² √I / (1 + B å √I)
- • γ = Activity coefficient
- • A = Debye-Hückel constant
- • z = Ion charge
- • I = Ionic strength
- • B = Constant
- • å = Ion size parameter
Applications
- • Electrochemistry
- • Solubility calculations
- • pH measurements
- • Buffer solutions
- • Ion exchange
- • Colligative properties
Common Ion Size Parameters
Cations
- • H⁺: 9.0 Å
- • Li⁺: 6.0 Å
- • Na⁺: 4.0 Å
- • K⁺: 3.0 Å
- • NH₄⁺: 2.5 Å
- • Mg²⁺: 8.0 Å
- • Ca²⁺: 6.0 Å
Anions
- • F⁻: 3.5 Å
- • Cl⁻: 3.0 Å
- • Br⁻: 3.0 Å
- • I⁻: 3.0 Å
- • OH⁻: 3.5 Å
- • NO₃⁻: 3.0 Å
- • SO₄²⁻: 4.0 Å
Typical Values
- • γ ≈ 1.0: Very dilute solutions
- • γ ≈ 0.8: I = 0.01 M
- • γ ≈ 0.6: I = 0.1 M
- • γ ≈ 0.4: I = 0.5 M
- • γ ≈ 0.2: I = 1.0 M