Which of the following pH levels indicates a higher concentration of hydrogen ions?

The correct answer is pH 3, as it indicates a higher concentration of hydrogen ions compared to the other options. The pH scale ranges from 0 to 14, where lower pH values signify higher acidity and consequently a greater concentration of hydrogen ions (H⁺).

In this scale, a pH of 0 is highly acidic, while a pH of 14 is very basic. A pH of 7 is considered neutral, meaning that the concentration of hydrogen ions is equal to the concentration of hydroxide ions (OH⁻). As the pH decreases from 7 to 0, the concentration of hydrogen ions increases exponentially. Thus, with pH levels of 5 and 3 being more acidic than 7, they both have higher concentrations of hydrogen ions than neutral solutions. However, pH 3 is significantly more acidic than pH 5, resulting in a greater hydrogen ion concentration.

On the other hand, pH 8 indicates a basic solution, which means it has a much lower concentration of hydrogen ions compared to the acidic pH values. Therefore, among the given choices, pH 3 indeed represents the highest concentration of hydrogen ions.