What is a characteristic of weak bases when dissolved in water?

Weak bases, when dissolved in water, exhibit the characteristic of partial ionization. This means they do not completely dissociate into ions. Instead, weak bases react with water to form hydroxide ions (OH⁻) through a reversible reaction. As a result, only a portion of the base molecules will react with water, leading to a lower concentration of hydroxide ions compared to strong bases, which completely dissociate.

The presence of these hydroxide ions contributes to an increase in the solution's pH, albeit not as significantly as strong bases would, since weak bases only partially react. This behavior is typical of weak bases, making the option of them reacting partially to form hydroxide ions the correct choice. Understanding this concept is crucial, as it highlights the differences between weak and strong bases in terms of their behavior in aqueous solutions.