1. What is pH?

pH is a logarithmic measure of the hydrogen ion concentration in a solution. It indicates the acidity or basicity of an aqueous solution, with values ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral.

2. How Does the Calculator Work?

The calculator uses the pH equation:

Where:

• \( [H^+] \) — Hydrogen ion concentration in moles per liter (M)
• \( \log \) — Base-10 logarithm

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

3. Importance of pH Calculation

Details: pH is critical in many chemical and biological processes. It affects enzyme activity, chemical solubility, and biological functions. Maintaining proper pH is essential in medicine, agriculture, environmental science, and industrial processes.

4. Using the Calculator

Tips: Enter hydrogen ion concentration in molarity (M). The value must be greater than 0. For very small concentrations, scientific notation may be needed (e.g., 1e-7 for neutral water).

5. Frequently Asked Questions (FAQ)

Q1: What is the pH of pure water?
A: At 25°C, pure water has a pH of 7 (neutral), with [H+] = 1×10⁻⁷ M.

Q2: Can pH be negative or greater than 14?
A: Yes, for very strong acids (pH < 0) or very strong bases (pH > 14), though these are rare in normal conditions.

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: What's the relationship between pH and pOH?
A: pH + pOH = 14 at 25°C. pOH measures hydroxide ion concentration similarly to how pH measures hydrogen ion concentration.

Q5: Why is pH important in biological systems?
A: Most enzymes function within narrow pH ranges. Blood pH is tightly regulated between 7.35-7.45; deviations can be life-threatening.