Mechanism of the reaction means the sequence of elementary steps involved in a chemical reaction, leading to the overall stoichiometry of the reaction. In fact, such mechanisms provide us the information regarding what each molecule is doing to the other during the course of the reaction.
A mechanism cannot be “proven” but becomes accepted if it is the only one that fits all known experimental facts.
By the mechanism of a chemical reaction is the actual series of discrete paths or steps encountered when reactants ultimately convert into final products in the course of a chemical reaction. A complex reaction involves a number of elementary steps. The mechanism of a reaction includes the sequence of elementary steps by which the reactant molecules are converted into products.