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. For pure water at 25°C, pH = -log(10⁻⁷) = 7.

2. How Does the Calculator Work?

The calculator uses the pH formula:

Where:

• \( [H^+] \) — Hydrogen ion concentration (mol/L)

Explanation: The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, while values above 7 indicate alkalinity.

3. Importance of pH Measurement

Details: pH measurement is crucial in various fields including chemistry, biology, environmental science, and water treatment. It helps determine the chemical behavior of substances and their suitability for different applications.

4. Using the Calculator

Tips: Enter hydrogen ion concentration in mol/L. The value must be greater than 0. For pure water at 25°C, the hydrogen ion concentration is 10⁻⁷ mol/L.

5. Frequently Asked Questions (FAQ)

Q1: What is the pH of pure water?
A: The pH of pure water at 25°C is 7, which is neutral on the pH scale.

Q2: How does temperature affect pH?
A: The pH of pure water decreases with increasing temperature due to changes in the ion product of water (Kw).

Q3: What is the relationship between pH and pOH?
A: pH + pOH = 14 at 25°C. This relationship comes from the ion product of water: Kw = [H⁺][OH⁻] = 10⁻¹⁴.

Q4: Can pH be negative or greater than 14?
A: Yes, for very concentrated strong acids, pH can be negative, and for very concentrated strong bases, pH can exceed 14.

Q5: Why is pH important in biological systems?
A: Most biological processes are pH-dependent. Enzymes, cellular functions, and metabolic processes operate within specific pH ranges.