Practice problem

What Is pH? — Definition & Overview

The pH of a solution can be figured out using litmus paper, which is also called pH paper.

Image Source: By Kanesskong (Own work) CC BY-SA 4.0, via Wikimedia Commons

The pH paper in the picture above turns blue when the concentration of OH $^-$ ions is greater than the H $^+$ ions. It turns red when the solution has more H $^+$ ions. Based on this information, which of the following statements about the pH of the solution is true?