It's not entirely accurate to say that pH cannot be below 1. While it's true that the pH scale is typically defined from 0 to 14, there are circumstances where solutions can have a pH below 1. Here's why:

* The pH scale is logarithmic: This means that each whole number change in pH represents a tenfold change in hydrogen ion concentration. So, a pH of 0 has ten times the hydrogen ion concentration of a pH of 1.

* Strong acids: Solutions of very strong acids can have pH values below 1. For example, concentrated hydrochloric acid (HCl) can have a pH close to -1.

* Superacids: These are acids even stronger than strong mineral acids. They can have negative pH values far below 1, with some reaching values around -30 or lower.

The limit of the pH scale:

While technically there's no real limit on how low the pH can go, the standard pH scale (0-14) is based on the assumption that the concentration of hydrogen ions is between 10^-14 M and 1 M.

In summary:

While most common solutions will have a pH between 0 and 14, extremely concentrated acids and superacids can have pH values significantly below 1. The pH scale is a logarithmic scale, and the limit of the scale is more a matter of practical limitations in the context of typical chemical reactions.