What happens to the concentration of hydrogen ions in a solution when a base is added?

When a base is added to a solution, the concentration of hydrogen ions decreases. This is because bases, by definition, are substances that can accept hydrogen ions (H⁺). When a base is introduced to a solution, it reacts with the hydrogen ions present, effectively reducing their concentration.

In solutions, pH is a measure of hydrogen ion concentration; as the concentration of hydrogen ions decreases, the pH of the solution increases, indicating a more basic or alkaline environment. This fundamental relationship between acids, bases, and hydrogen ion concentration is crucial in understanding the chemistry of solutions and their properties.