What type of chemical reaction is represented by the equation AB + CD = AD + CB?

The given equation AB + CD = AD + CB represents an exchange reaction, also known as a double displacement reaction. In this type of reaction, the components of two compounds (AB and CD) exchange partners, resulting in the formation of two new compounds (AD and CB).

In the context of this reaction, A and C come together to form a new compound (AD), while B and D do the same to form another compound (CB). This exchange is a hallmark of double displacement, where ions or elements switch places between the reactants.

Understanding exchange reactions is important because they are common in various chemical processes, including those in biological systems and industrial applications. For example, they can occur in neutralization reactions where an acid reacts with a base.

The other types of reactions mentioned do not involve the exchange of components in the same manner. Synthesis reactions involve combining two or more reactants to form a single product, decomposition reactions involve breaking down a compound into simpler substances, and combustion reactions typically involve a substance reacting with oxygen, producing heat and light.