Ionic Strength Calculator: Electrolyte Solutions
Calculate the ionic strength of electrolyte solutions. Understand how ionic strength affects activity coefficients, electrode potentials, and biological processes.
What is Ionic Strength?
Ionic strength (I) measures the total concentration of ions in a solution, weighted by the square of their charges. It affects how ions interact with each other and with charged surfaces. High ionic strength reduces electrostatic interactions and is critical in biochemistry (protein folding), electrochemistry, and analytical chemistry.
🧪 Ionic Strength Calculator
Use our free calculator for instant, accurate results.
📐 Formula
I = ½ × Σ(cᵢ × zᵢ²)
cᵢ = molar concentration of ion i (mol/L), zᵢ = charge of ion i. Sum over all ionic species in solution.
📝 Worked Example
0.1 M NaCl (Na⁺ and Cl⁻, both z=1):
I = ½ × (0.1×1² + 0.1×1²) = ½ × 0.2 = 0.1 M
0.1 M MgSO₄ (Mg²⁺ z=2, SO₄²⁻ z=2):
I = ½ × (0.1×4 + 0.1×4) = 0.4 M
📝 How to Use the Calculator
❓ FAQ
Why do divalent ions contribute more to ionic strength?
Because I ∝ z². A Ca²⁺ ion (z=2) contributes 4× more than Na⁺ (z=1) at the same concentration.
Why is ionic strength important in biological buffers?
Physiological ionic strength (~0.15 M) affects enzyme activity, protein structure, and membrane potential. Deviations can disrupt cellular function.
Veer Kumavat
Founder & AuthorVeer is a 14-year-old student from Nashik, Maharashtra, who built SciFi Calculators to help students worldwide master STEM subjects. He is passionate about making complex science and math problems accessible through intuitive digital tools.