Which of the following describes a property of hydroxide ions?

Hydroxide ions (OH-) are known for their role in affecting the pH of a solution. They are considered to be basic species which can react with acids to neutralize them, thereby resulting in an increase in the pH of the solution. The presence of hydroxide ions means that the solution has fewer hydrogen ions (H+), which directly correlates to a higher pH since pH is a measure of the concentration of hydrogen ions in a solution.

When hydroxide ions are added to water, they can accept protons, thus reducing the concentration of hydrogen ions. This shift towards a higher pH indicates a more basic or less acidic solution. Therefore, the characteristic of hydroxide ions that they increase the pH of solutions is accurate and highlights their fundamental role in acid-base chemistry.