* Brønsted-Lowry Definition: A base is a substance that accepts hydrogen ions (H+). When a base is added to a solution, it reacts with H+ ions, removing them from the solution.
* pH Scale: The pH scale measures the acidity or basicity of a solution. Lower pH values indicate higher H+ concentration (acidic), while higher pH values indicate lower H+ concentration (basic).
* Hydroxide Ions (OH-): Many bases produce hydroxide ions (OH-) in solution. Hydroxide ions react with hydrogen ions to form water (H2O), further decreasing the H+ concentration.
Example:
Consider adding sodium hydroxide (NaOH) to water. NaOH is a strong base and dissociates completely in water to form sodium ions (Na+) and hydroxide ions (OH-):
NaOH(aq) → Na+(aq) + OH-(aq)
The hydroxide ions react with hydrogen ions already present in the water:
H+(aq) + OH-(aq) → H2O(l)
This reaction removes H+ ions from the solution, increasing the pH and making the solution less acidic (more basic).
