Which type of substance releases OH⁻ ions in water?

Bases are substances that, when dissolved in water, increase the concentration of hydroxide ions (OH⁻). This property is a key characteristic of bases. For instance, when sodium hydroxide (NaOH) is dissolved in water, it dissociates to release sodium ions (Na⁺) and hydroxide ions (OH⁻), resulting in an increase in the OH⁻ concentration of the solution.

In contrast, acids release hydrogen ions (H⁺) in solution, which can lead to a decrease in pH, while neutral solutions contain a balanced concentration of H⁺ and OH⁻ ions, resulting in a pH of 7. Organic compounds may not necessarily produce OH⁻ when dissolved in water and often serve different roles in biological systems. This makes bases the correct answer to the question regarding substances that release OH⁻ ions in water.