Here's why:
* Acids donate protons (H⁺) when dissolved in water. These protons immediately react with water molecules to form hydronium ions (H₃O⁺).
* Bases accept protons, which effectively reduces the concentration of H₃O⁺ ions in solution.
Therefore, the higher the [H₃O⁺] concentration, the more acidic the solution. The lower the [H₃O⁺] concentration, the more basic (alkaline) the solution.
Key Points:
* pH scale: The pH scale is a logarithmic scale that measures the [H₃O⁺] concentration. A lower pH indicates a higher [H₃O⁺] concentration and a more acidic solution.
* pOH scale: The pOH scale measures the [OH⁻] concentration, which is inversely related to [H₃O⁺] concentration. A higher pOH indicates a lower [H₃O⁺] concentration and a more basic solution.
Example:
A solution with a [H₃O⁺] concentration of 1 x 10⁻⁵ M would have a pH of 5, indicating a weakly acidic solution.
