AFOQT Practice Test

Which type of reaction involves one element replacing another in a compound?

1. Synthesis Reaction

2. Decomposition Reaction

3. Single-Displacement Reaction

4. Combustion Reaction

The correct answer is: Single-Displacement Reaction

The correct choice highlights the nature of a single-displacement reaction, which occurs when one element replaces another in a compound. This type of reaction can be represented by the general formula A + BC → AC + B, where A displaces B in the compound BC, forming a new compound AC and releasing B as a separate entity. In contrast, synthesis reactions involve the combination of two or more substances to form a single compound, which is a different process altogether. Decomposition reactions break down a compound into simpler substances or elements, which does not involve any replacement of elements. Combustion reactions typically involve a fuel reacting with oxygen to produce heat and light, often forming products like carbon dioxide and water, but do not exhibit the displacement characteristic essential to the correct answer.