How is a base defined in chemistry?

A base in chemistry is correctly defined as a substance that accepts protons or produces hydroxide ions in an aqueous solution. This definition is grounded in the Brønsted-Lowry theory, which describes bases as proton acceptors. This theory expands the understanding of basicity beyond just traditional definitions associated with pH levels.

When a base accepts a proton (H+), it can neutralize acids and participate in various chemical reactions, contributing to the concept of acidity and basicity in solution. Additionally, many bases, especially in the sense of the Arrhenius definition, increase the concentration of hydroxide ions (OH-) in water, further demonstrating their basic nature.

Understanding this definition is crucial for grasping broader chemical concepts, such as pH levels and acid-base equilibrium, as it frames how different substances interact chemically in solutions.