Bases are substances that can accept hydrogen ions (H+) in a solution. This ability to accept protons (H+) characterizes a base in the context of the Brønsted-Lowry acid-base theory. When a base is dissolved in water, it often dissociates to release hydroxide ions (OH–), which can then react with hydrogen ions to form water.
For example, consider sodium hydroxide (NaOH). When it is dissolved in water, it dissociates into sodium ions (Na+) and hydroxide ions (OH–). The hydroxide ions can accept hydrogen ions from acidic solutions, thereby decreasing the concentration of H+ in that solution and increasing the pH, making the solution less acidic.
In summary, bases play a crucial role in chemical reactions by facilitating the acceptance of hydrogen ions, which can lead to a variety of important chemical processes, including neutralization reactions where acids and bases interact to form water and salts.