Final answer:
The reaction AB → A + B is a decomposition reaction, where a single compound breaks down into simpler substances or elements.
Step-by-step explanation:
The general form AB → A + B characterizes a decomposition reaction. In a decomposition reaction, a single compound breaks down into two or more elements or simpler compounds. This type of reaction is the opposite of a combination or synthesis reaction, where two or more substances combine to form a single new substance, represented as A + B → AB. Decomposition reactions are integral in chemistry because they break down complex molecules into simpler ones, providing a way to understand and study the basic components of a substance.