How is a single substitution reaction typically represented?

In a single substitution reaction, one element replaces another element in a compound. This type of reaction can be represented with a general formula that shows the reactants and products involved. The correct representation for a single substitution reaction shows a single element, A, reacting with a compound, BC. In this reaction, A displaces the element B from the compound, resulting in the formation of a new compound AC and the free element B.

Thus, the representation B reflects this process accurately: A interacts with BC to yield AC and B as products, illustrating the core concept of a single substitution reaction where one atom is swapped out for another.

In contrast, the other options depict different types of reactions. For example, the first option represents a double substitution reaction, the third option illustrates a formation reaction where two elements combine to form a compound, and the last option again denotes a double replacement reaction where two compounds react to form two new compounds. Each of these scenarios involves different mechanisms than what occurred in a single substitution reaction.