Hydrogen Ion Concentration Calculator
Convert between pH, pOH, hydrogen ion concentration [H⁺], and hydroxide ion concentration [OH⁻]
Calculate Ion Concentrations
pH scale from 0 (acidic) to 14 (basic)
Temperature affects ion product of water (Kw)
Note: Calculations assume 25°C where Kw = 1.0 × 10⁻¹⁴
Calculation Results
Calculation Details
Formula: [H⁺] = 10^(-pH)
Calculation: [H⁺] = 10^(-pH) = 10^(-0) = 1.000e+0 M
Relationship: pH + pOH = 14 (at 25°C)
Water equilibrium: [H⁺] × [OH⁻] = Kw = 1.0 × 10⁻¹⁴
Solution type:
Solution Analysis
Example Calculation
Acidic Solution Example
Question: What is the hydrogen ion concentration of a solution with pH 3.5?
Given: pH = 3.5
Find: [H⁺] concentration
Temperature: 25°C
Step-by-Step Solution
Step 1: Apply formula: [H⁺] = 10^(-pH)
Step 2: Calculate: [H⁺] = 10^(-3.5) = 3.16 × 10⁻⁴ M
Step 3: Find pOH: pOH = 14 - pH = 14 - 3.5 = 10.5
Step 4: Find [OH⁻]: [OH⁻] = Kw / [H⁺] = 1.0 × 10⁻¹⁴ / 3.16 × 10⁻⁴ = 3.16 × 10⁻¹¹ M
Answer: [H⁺] = 3.16 × 10⁻⁴ M, solution is acidic (strong acid)
pH Scale
Key Formulas
pH Formula
pH = -log([H⁺])
Negative log of H⁺ concentration
pOH Formula
pOH = -log([OH⁻])
Negative log of OH⁻ concentration
Relationship
pH + pOH = 14
At 25°C (298 K)
Water Equilibrium
[H⁺][OH⁻] = Kw
Kw = 1.0 × 10⁻¹⁴ at 25°C
Common Solutions
Understanding Hydrogen Ion Concentration
What are Hydrogen Ions?
Hydrogen ions (H⁺) are protons released when acids dissolve in water. They're also represented as hydronium ions (H₃O⁺) when combined with water molecules. The concentration of these ions determines the acidity or basicity of a solution.
Why is this Important?
- •Determines solution's acidic or basic nature
- •Critical for biological processes and enzyme function
- •Essential for water treatment and environmental monitoring
- •Important in industrial processes and quality control
Water Equilibrium
Water Autoionization
H₂O ⇌ H⁺ + OH⁻
Water molecules dissociate into ions
Ion Product
Kw = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴
At 25°C, constant for all aqueous solutions
Logarithmic Scale
pH scale compresses large concentration ranges
Each pH unit = 10× concentration change