1. What is pH?

pH is a measure of the acidity or basicity of an aqueous solution. It is defined as the negative logarithm (base 10) of the hydrogen ion concentration. The pH scale typically ranges from 0 to 14, with 7 being neutral.

2. How Does the Calculator Work?

The calculator uses the pH formula:

Where:

• \( [H^+] \) — Hydrogen ion concentration (mol/L)
• \( \log_{10} \) — Logarithm base 10

Explanation: The pH value is inversely related to the hydrogen ion concentration - as [H+] increases, pH decreases.

3. Importance of pH Calculation

Details: pH measurement is crucial in chemistry, biology, medicine, environmental science, and many industrial processes. It affects chemical reactions, biological functions, and material properties.

4. Using the Calculator

Tips: Enter hydrogen ion concentration in mol/L. The value must be positive (concentration > 0). The result is dimensionless.

5. Frequently Asked Questions (FAQ)

Q1: What is the pH of pure water?
A: Pure water at 25°C has a pH of 7 (neutral), with [H+] = 1.0 × 10⁻⁷ mol/L.

Q2: What pH values are considered acidic and basic?
A: pH < 7 is acidic, pH > 7 is basic (alkaline), and pH = 7 is neutral.

Q3: How does temperature affect pH?
A: The pH of neutral water changes with temperature (e.g., pH ≈ 6.81 at 50°C) because water's self-ionization changes with temperature.

Q4: Can pH be negative or greater than 14?
A: Yes, for very strong acids ([H+] > 1 mol/L) pH can be negative, and for very strong bases pH can exceed 14.

Q5: What's the relationship between pH and pOH?
A: pH + pOH = 14 at 25°C. pOH is calculated similarly using hydroxide ion concentration.