1. What is the pH Formula?

The pH formula calculates the acidity or alkalinity of a solution from the hydrogen ion concentration. pH is defined as the negative logarithm (base 10) of the hydrogen ion activity in a solution.

2. How Does the Calculator Work?

The calculator uses the pH formula:

Where:

• \( [H^+] \) — Hydrogen ion concentration in moles per liter (M)

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

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 stability.

4. Using the Calculator

Tips: Enter hydrogen ion concentration in mol/L (M). The value must be positive. 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: What pH values are acidic and basic?
A: pH < 7 is acidic, pH = 7 is neutral, pH > 7 is basic (alkaline).

Q3: How is pH measured experimentally?
A: Typically using a pH meter with a glass electrode or pH indicator papers.

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

Q5: Does temperature affect pH?
A: Yes, the pH of neutral water changes with temperature (e.g., pH 7.47 at 0°C, 6.14 at 100°C).