What does a pH lower than 7 indicate about a solution?

A pH lower than 7 indicates that a solution is acidic. The pH scale ranges from 0 to 14, where a pH of 7 is considered neutral, meaning the solution is neither acidic nor alkaline. As you move below 7, the concentration of hydrogen ions (H⁺) in the solution increases, which is characteristic of an acidic solution. This increase in hydrogen ions is what causes the pH value to drop, distinguishing acidic solutions from neutral and alkaline (or basic) solutions, which have a pH above 7. Understanding the behavior of acids, bases, and their pH levels is essential in many biological and chemical processes, making this concept fundamental in biology and other sciences.