Which chemical reaction type involves an element taking the place of another in a compound?

The type of chemical reaction in which an element takes the place of another element in a compound is known as a Single Replacement Reaction. In this reaction, one element reacts with a compound and displaces another element from that compound, forming a new compound and a free element.

For example, if zinc reacts with hydrochloric acid, zinc displaces the hydrogen in the acid, resulting in the formation of zinc chloride and hydrogen gas. This clearly illustrates how one element replaces another within the compound.

The other types of reactions listed do not involve this specific displacement mechanism. In a Double Replacement Reaction, two compounds exchange parts, but no single element displaces another; rather, both compounds rearrange. A Synthesis Reaction involves two or more substances combining to form a new compound, and a Decomposition Reaction involves a compound breaking down into simpler substances. Both of these types do not reflect the process of one element taking the place of another in a compound, which is the hallmark of a Single Replacement Reaction.