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 hydronium ion concentration [H₃O⁺]. 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:

• \( pH \) — pH value (dimensionless)
• \( [H_3O^+] \) — Hydronium ion concentration (mol/L)

Explanation: The formula calculates the negative base-10 logarithm of the hydronium ion concentration to determine the pH of a solution.

3. Importance of pH Calculation

Details: pH measurement is crucial in various fields including chemistry, biology, medicine, environmental science, and many industrial processes. It helps determine the acidity or alkalinity of solutions which affects chemical reactions, biological functions, and environmental conditions.

4. Using the Calculator

Tips: Enter the hydronium ion concentration in mol/L. The value must be greater than 0. The calculator will compute the corresponding pH value.

5. Frequently Asked Questions (FAQ)

Q1: What is the relationship between pH and [H₃O⁺]?
A: pH and [H₃O⁺] have an inverse logarithmic relationship. As [H₃O⁺] increases, pH decreases, indicating higher acidity.

Q2: What is considered a neutral pH?
A: A pH of 7 is considered neutral at 25°C, which corresponds to [H₃O⁺] = 1.0 × 10⁻⁷ mol/L.

Q3: How does temperature affect pH?
A: The pH of neutral water changes with temperature due to the temperature dependence of the water ionization constant (Kw).

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: What's the difference between [H⁺] and [H₃O⁺]?
A: In aqueous solutions, protons (H⁺) immediately associate with water molecules to form hydronium ions (H₃O⁺). For practical purposes in pH calculations, they are often used interchangeably.