Final answer:
The branching step in a chain reaction involves the generation of additional products using reaction products as reactants. The synthesis of water from H₂ and O₂ serves as an example of this. The reaction involves breaking and forming chemical bonds to produce H₂O.
Step-by-step explanation:
The branching step in a chain reaction refers to the process where a reaction product acts as a reactant, generating additional products and continuing the reaction. In the case of the mixing of H₂ and O₂, the synthesis of water serves as an example. The reaction involves the breaking of chemical bonds between oxygen atoms in O₂ and hydrogen atoms in H₂, and the formation of new bonds between hydrogen and oxygen to produce H₂O.