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Why must a proposed reaction mechanism account for all observed products?

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dissociation of E–N — reaction mechanism Possible energy diagram for the dissociation of a covalent molecule, E–N, into its ions E⁺ and N⁻ (see text).

A proposed reaction mechanism must account for all observed products because the identification of these substances is fundamental to defining the reaction course. In chemistry, the mechanism serves as a detailed description of the process by which starting materials are transformed into final products, including the specific changes in bonding patterns and molecular structures.12

Because the mechanism must accurately reflect the actual path taken from reactants to products, any valid proposal must be consistent with the experimental evidence of what is formed. If a mechanism fails to account for the observed products, it cannot be considered a correct representation of the reaction. Furthermore, identifying all products—including those that may be transient or formed in small amounts—is essential for distinguishing between different potential pathways, such as those under kinetic versus thermodynamic control. By ensuring that the mechanism explains the formation of all observed substances, chemists can better understand the reaction's nature and predict the outcomes of similar, untried chemical systems.12