Bases are defined by their ability to accept protons (H+) or donate pairs of valence electrons. In terms of pH, which is a measure of the acidity or basicity of a solution, bases typically have a pH greater than 7. This is due to the ionization of a base in solution, which leads to an increase in hydroxide ions (OH-). The more hydroxide ions present, the higher the pH, indicating a more basic solution.
The pH scale ranges from 0 to 14, where values below 7 indicate acidic solutions, values exactly at 7 are neutral (such as pure water), and values above 7 represent basic (alkaline) solutions. Therefore, when identifying the common characteristic of bases, it is accurate to conclude that they are characterized by a pH greater than 7.