The pH scale is a logarithmic scale used to measure the acidity or basicity of an aqueous solution. It ranges from 0 to 14, with 0 being the most acidic, 7 being neutral, and 14 being the most basic.

An alkaline solution is a solution that has a pH value greater than 7. This means that the solution has a higher concentration of hydroxide ions (OH-) than hydrogen ions (H+). The more alkaline the solution, the higher the pH value.

Therefore, alkaline solutions cannot have pH values below 7.