pH Chemistry Example 1

Follow the full solution, then compare it with the other examples linked below.

Example 1

easy
Calculate the pH of a solution with [H+]=1.0×10−4 M[\text{H}^+] = 1.0 \times 10^{-4}\,\text{M}.

Solution

  1. 1
    Recall the pH formula: pH=−log⁡[H+]\text{pH} = -\log[\text{H}^+], where [H+][\text{H}^+] is the hydrogen ion concentration in mol/L.
  2. 2
    Identify the given value: [H+]=1.0×10−4 mol/L[\text{H}^+] = 1.0 \times 10^{-4}\,\text{mol/L}.
  3. 3
    Apply the formula: pH=−log⁡(1.0×10−4)=−(−4)=4\text{pH} = -\log(1.0 \times 10^{-4}) = -(-4) = 4

Answer

pH=4\text{pH} = 4
The pH scale is logarithmic — each unit change in pH represents a tenfold change in hydrogen ion concentration. A pH of 4 means the solution is acidic.

About pH

A logarithmic scale ranging from 0 to 14 that quantifies the hydrogen ion concentration [H+][\text{H}^+] in an aqueous solution, where values below 7 indicate acidic.

Learn more about pH →

More pH Examples

Example 2 medium

A solution has pH = 9. Calculate [formula] and [formula].

Example 3 medium

What is the pH of a [formula] HCl solution? (HCl is a strong acid.)

Example 4 medium

Compare a solution with pH 2 and a solution with pH 5. How many times greater is the hydrogen-ion co

← All pH Examples pH Concept