Final answer:
Oxidation is the loss of electrons or increase in oxidation state, while reduction is the gain of electrons or decrease in oxidation state. These processes are part of redox reactions, where the substance that loses electrons is the reducing agent, and the substance that gains electrons is the oxidizing agent.
Step-by-step explanation:
Oxidation and reduction are chemical processes that involve the transfer of electrons between atoms, which are collectively known as redox reactions. Oxidation refers to the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.
Conversely, reduction refers to the gain of electrons or a decrease in oxidation state. These processes occur together; when one substance undergoes oxidation, another undergoes reduction. For instance, in the reaction of zinc metal with hydrogen ions, zinc gets oxidized by losing electrons and becomes zinc ions, while hydrogen ions gain electrons and are reduced to hydrogen gas. In this context, zinc acts as the reducing agent because it provides electrons, and hydrogen ions act as the oxidizing agent because they accept electrons.