Question

What is the pH of a solution with a concentration of 1.3 × 10-3 molar H3O+? Show, or explain, the work used to solve this problem.

Answer 1

When an acid is added to water, the hydrogen ions released bind to the water molecules to form hydronium ions (H₃O⁺). Each hydrogen ion binds to one molecule of water, so the concentration of hydronium ions formed is equivalent to the hydrogen ions present. Therefore,
[H⁺] = 1.3 x 10⁻³

Next,
pH = -log[H⁺]
pH = -log(1.3 x 10⁻³)
pH = 2.89

The pH of the solution will be 2.89