Answer:
increasing the number of hydrogen ions.
Step-by-step explanation:
- pH is a measure of the acidity or alkalinity of a solution.
pH = -log[H⁺].
- The presence of H⁺ is the responsible of the acidity of the solution.
- As the concentration of H⁺ increases, the acidity of the solution increases and so, pH decreases.
- So, the right choice is: increasing the number of hydrogen ions.