Which type of reaction involves the transfer of electrons?

The type of reaction that involves the transfer of electrons is known as a redox reaction. In these reactions, there is a concurrent process of oxidation and reduction; one species loses electrons (oxidation), while another gains those electrons (reduction). This transfer of electrons can lead to changes in the oxidation states of the reacting species, fundamentally altering their chemical identity and behavior.

For example, in a reaction where metal reacts with a nonmetal, such as the oxidation of iron in rust formation, iron loses electrons and becomes oxidized, while oxygen gains electrons and is reduced. Such electron transfer is crucial to various biochemical processes as well as industrial applications like battery function.

The other types of reactions listed—synthesis, decomposition, and double displacement—do not inherently involve the transfer of electrons in the same way that redox reactions do. Synthesis reactions involve combining two or more substances to form a new compound, decomposition reactions break a compound down into simpler substances, and double displacement reactions involve the exchange of ions between two compounds without transferring electrons.