Which of the following pH values indicates an acidic solution?

A pH value less than 7 indicates an acidic solution because the pH scale ranges from 0 to 14. A pH of 7 is considered neutral, representing a balance between acidity and alkalinity, which is the case for pure water at 25°C (77°F). When the pH drops below 7, it indicates an increase in hydrogen ion concentration, thus making the solution acidic. Conversely, a pH greater than 7 signals a basic or alkaline solution, where the concentration of hydroxide ions exceeds that of hydrogen ions. Values like 10 reflect this basic nature rather than acidity. Therefore, a pH value of less than 7 clearly signifies an acidic environment.