Which of the following best describes an oxidant?

An oxidant is best described as a substance that readily accepts electrons during a chemical reaction. This characteristic is central to the role of oxidants in oxidation-reduction (redox) reactions, where oxidation involves the loss of electrons, and reduction entails the gain of electrons. When an oxidant accepts electrons, it facilitates the oxidation of another substance, which loses those electrons.

This definition highlights the fundamental nature of oxidants in various chemical and biological processes, such as cellular respiration, combustion, and various water treatment methods. The ability of an oxidant to accept electrons is what classifies it as such, playing a critical role in maintaining redox balance and affecting the reactivity of different compounds in a solution.

Conversely, describing a substance that provides heat, always exists as a gas, or reduces other compounds does not accurately capture the essence of what an oxidant does in the realm of chemistry. Each of these alternatives lacks the core characteristic that distinguishes oxidants in chemical processes.