pH Calculator

How to Calculate pH

The pH scale is used to measure the acidity or basicity of a solution. It ranges from 0 to 14, with 7 being neutral, below 7 acidic, and above 7 basic.

What is the Formula?

The formula for calculating pH is:

\[ \text{pH} = -\log_{10}[\text{H}^+] \]

Where:

• [H⁺] is the concentration of hydrogen ions in mol/L

What are the calculation steps?

1. Determine the concentration of H⁺ ions in the solution
2. Take the negative logarithm (base 10) of this concentration
3. The result is the pH of the solution

Example Calculation

Let's calculate the pH of a 0.01 M HCl solution:

Given:

• HCl concentration = 0.01 M
• HCl is a strong acid, so it dissociates completely in water

Step 1: Determine [H⁺]

[H⁺] = 0.01 M (equal to HCl concentration)

Step 2: Apply the formula

pH = -log[H⁺] = -log(0.01)

Step 3: Calculate the result

pH = 2

Therefore, the pH of a 0.01 M HCl solution is 2, which is acidic.

pH Scale Diagram

This diagram illustrates the pH scale:

The pH scale ranges from 0 (most acidic) to 14 (most basic), with 7 being neutral. Each unit represents a tenfold change in H⁺ concentration.