Which statement best describes a base in the context of the Brønsted-Lowry theory?

In the context of the Brønsted-Lowry theory, a base is defined as a substance that accepts protons (H+). This theory, developed by Johannes Nicolaus Brønsted and Thomas Lowry, fundamentally characterizes acids as proton donors and bases as proton acceptors. When a base accepts a proton, it can form a conjugate acid, indicating a direct interaction where it captures the proton from an acid, thus facilitating a chemical reaction.

For instance, when ammonia (NH₃) interacts with water, it accepts a proton from the water molecule, forming the ammonium ion (NH₄⁺) and hydroxide ions (OH⁻). This process exemplifies how a base operates under the Brønsted-Lowry theory by accepting protons from acids.

While the other statements contain elements that relate to some behaviors of bases, they do not capture the definition as precisely. There isn't a need to focus on other choices, as they do not define a base in the Brønsted-Lowry framework. Rather, the definition emphasizes the proton-accepting characteristic that is central to this theory.