1. What is pH and [H⁺]?

pH is a logarithmic measure of the hydrogen ion concentration in a solution. [H⁺] represents the molar concentration of hydrogen ions (protons) in solution, which determines the acidity.

2. How Does the Calculator Work?

The calculator uses the fundamental pH equation:

Where:

• \( [H^+] \) — Hydrogen ion concentration (mol/L)
• \( pH \) — pH value (dimensionless, range 0-14)

Explanation: The pH scale is logarithmic, so each whole pH value below 7 is ten times more acidic than the next higher value.

3. Importance of [H⁺] Calculation

Details: Knowing the hydrogen ion concentration is crucial in chemistry, biology, medicine, and environmental science as it affects chemical reactions, enzyme activity, and biological systems.

4. Using the Calculator

Tips: Enter a pH value between 0 (very acidic) and 14 (very basic). The calculator will provide the corresponding hydrogen ion concentration in both decimal and scientific notation.

5. Frequently Asked Questions (FAQ)

Q1: What is the [H⁺] of pure water?
A: Pure water at 25°C has pH = 7, so [H⁺] = 10⁻⁷ = 0.0000001 mol/L.

Q2: How does pH relate to pOH?
A: In aqueous solutions at 25°C, pH + pOH = 14. pOH = -log[OH⁻].

Q3: What is the [H⁺] of stomach acid?
A: Stomach acid typically has pH ≈ 1.5-3.5, corresponding to [H⁺] ≈ 0.03-0.003 mol/L.

Q4: Can pH be negative or >14?
A: Yes, for very concentrated acids (pH < 0) or bases (pH > 14), though these are rare in biological systems.

Q5: Why is the pH scale logarithmic?
A: The logarithmic scale conveniently compresses the wide range of hydrogen ion concentrations (10⁰ to 10⁻¹⁴ mol/L) into a manageable 0-14 scale.