What do oxidation-reduction (redox) reactions involve?

Oxidation-reduction (redox) reactions are characterized by the transfer of electrons between substances. In these reactions, one species loses electrons (oxidation) while another gains electrons (reduction). This transfer of electrons is what fundamentally drives the changes in oxidation states of the reactants involved.

Understanding redox reactions requires recognizing that the flow of electrons is crucial for energy transfer and transformation in chemical processes. For instance, in cellular respiration, glucose undergoes oxidation, whereas oxygen is reduced, illustrating this principle in biological systems.

The other choices—transfer of protons, transfer of neutrons, and formation of covalent bonds—do not accurately describe the key process in redox reactions. Oxidation involves changes in electron count rather than proton or neutron transfer, and covalent bond formation is a different type of chemical interaction that does not inherently involve electron transfer as seen in redox reactions.