What does a pH below 7 indicate about a solution?

A pH below 7 indicates that a solution is acidic. The pH scale ranges from 0 to 14, where 7 is considered neutral, such as pure water. Values lower than 7 represent increasing acidity, with 0 being the most acidic. For instance, common acidic substances include vinegar and lemon juice, both of which have a pH lower than 7.

When discussing solutions, understanding pH is crucial, as it affects chemical reactions, the behavior of molecules, and the overall environment of various processes, including those in hair coloring and treatments. An acidic environment can contribute to the effectiveness of certain hair color processes and can help in the maintenance of hair health.