What happens to the pH of a solution when hydrogen ions increase?

When hydrogen ions increase in a solution, the pH of that solution decreases. pH is a measure of the acidity or basicity of a solution, and it is defined on a logarithmic scale. This means that for every unit of pH change, there is a tenfold change in hydrogen ion concentration.

As the concentration of hydrogen ions increases, it signifies that the solution is becoming more acidic. Since pH is inversely related to hydrogen ion concentration, as the number of hydrogen ions rises, the pH value drops. For instance, a solution with a pH of 7 is neutral; a pH less than 7 indicates an acidic solution with a higher concentration of hydrogen ions, while a pH greater than 7 indicates a basic solution with fewer hydrogen ions.

In summary, an increase in hydrogen ions leads to a decrease in pH, making the answer correct. Understanding this relationship is crucial in many scientific fields, including chemistry, biology, and skincare formulations.